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    PESTICIDE RESIDUES IN FOOD - 1984


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1984




    The monographs



    Data and recommendations of the joint meeting
    of the FAO Panel of Experts on Pesticide Residues
    in Food and the Environment and the
    WHO Expert Group on Pesticide Residues
    Rome, 24 September - 3 October 1984

    Food and Agriculture Organization of the United Nations
    Rome 1985

    PROPAMOCARB

    IDENTITY

    Chemical Name (IUPAC and C.A.): Propyl 3-(dimethylaminopropyl)=
                          carbamate C.A. Registry No. [67338-67-4]

    Synonyms:             PREVICURRN, PREVEX, FILEX, BANOL, DYNONE N
                          Schering Code Nos. SN 66752 and ZK 66752

    Structural Formula:   CH3                     O
                              \                   "
                                N - (CH2)3 - NH - C - O - C3H7
                              /
                          CH3

    Molecular formula:    C9H20N2O2

    Information on identity and properties of the hydrochloride salt,

                          C9H21C1N2O2

    Molecular weight:     224.7

    State:                The technical hydrochloride salt is a
                          colourless, very hygroscopic crystalline solid
                          with a faint aromatic odour.

    Melting point:        45-55°C

    Vapour pressure:      6 × 10-6 Torr at 25°C

    Dissociation
    constant (pKa):       9.1

    Octanol/water
    partition
    coefficient:          2.5 × 10-3

    Solubility (at 25° C) >700 g/l in water; >500 g/l in methanol;
                          >430 g/l in methylene chloride; >300 g/l in
                          isopropanol; 23 g/l in ethyl acetate; <0.1 g/l
                          in toluene and hexane.

    Stability:            Propamocarb hydrochloride is very stable to
                          hydrolysis. Even at pH 14 the half-life is 5
                          days. At pH 9 the half-life was calculated to be
                          1.3 × 103 years, increasing at pH 5 to 1.3 ×
                          107 years. The product is stable at 55°C for
                          over 2 years, and to light, even on the addition
                          of acetone.

    Technical material and impurities

         The technical material has a purity in excess of 95% of the
    hydrochloride salt.

         The main impurities are as follows:

         N,N-dimethyl-1,3-diaminopropane dihydrochloride     max. 5%
         N,N-bis(3-dimethylaminopropyl)urea dihydrochloride  max. 2%

         Solvents                                            max. 1%

    Formulation: "PREVICUR N" is an aqueous solution containing 722 g/l
                   propamocarb hydrochloride a.i.

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         Propamocarb is available only as the hydrochloride. It is a
    systematic fungicide especially active against Oomycetes fungi of the
    genera Pythium, Aphanomyces, Phytophtera, Peronospora,
    Pseudoperonospora and Bremia causing damping-off, root and stem rot,
    leaf blight, fruit rot and downy mildew. It is applied as a preventive
    soil drench or by soil incorporation, seed dressing, dipping of bulbs
    and roots or foliar spraying.

         The meeting was informed that propamocarb as hydrochloride is
    registered and sold in more than 30 countries (Table 1).

    Pre-harvest treatments

         Propamocarb is formulated only as 72.2% hydrochloride in aqueous
    solution. This formulation is used for foliar application as well as
    for seed dressing, soil drenching and soil incorporation.

    Post-harvest treatments

         No recommendations have been reported for post-harvest uses of
    propamocarb.

    Other uses

         Propamocarb is approved for use on ornamentals in many countries
    and also for use on tobacco and turf.


        Table 1.  Registrations and approved uses of propamocarb

                                                                                                                                 
                                       Approved application rate
    Country             Commodity                                                   Applications                  Pre-harvest
                                       formulation containing 72.2%                                               interval
                                       propamocarb hydrochloride a.i.
                                                                                                                                 

    Austria 1           Vegetables     0.15-0.25%:5 l/m2        5.4-9.0 g/m2        Seedbed drench                na

                        Cucumbers      0.25%:3 l/m2             5.4 g/m2            Post-seeding drench           cucumbers-
                                       0.15%:0.2 l/plant        0.22 g/plant        Post-plant drench             2 weeks
                                                                                    (repeat after 4 weeks)

                        Lettuce 2      2 l/ha                   1.44 kg/ha          Several sprays beginning      lettuce -
                                                                                    10 days after planting        3 weeks
                                                                                    (10-14 day intervals)

                        Strawberries   0.2%                     144 g/hl            Pre-plant dip
                                       0.5 ml/plant             0.36 g/plant        Two sprays after
                                                                                    planting                      ns
                                                                                    (4 week intervals)

    Bulgaria            Peppers        0.15-0.2%                4.3-5.8 g/m2        Post-seeding drench           na
                                       0.15-0.2%                0.27 g/plant        Post-plant drench             ns

    Chile               Sugar beet     40 ml/kg                 28.8 g/kg           Seed treatment                na

    Colombia            Soybeans       0.5-2 ml/kg              0.36-1.44 g/kg      Seed treatment                na

    Czechoslovakia 1    Vegetables     0.15%                    108 g/hl            Seedbed drench                na
                        Cucumbers  )
                        Tomatoes   )   0.15%:100 ml/plant       0.22 g/plant        Drench                        ns

    France 1            Vegetables  )  14 ml/m2                 10.1 g/m2           Drench                        ns
                        Strawberries)  300 ml/m3                217 g/m3            Soil incorporation
                                                                                                                                 

    Table 1.  (continued)

                                                                                                                                 
                                       Approved application rate
    Country             Commodity                                                   Applications                  Pre-harvest
                                       formulation containing 72.2%                                               interval
                                       propamocarb hydrochloride a.i.
                                                                                                                                 

    German              Tomatoes       0.15%:4 l/m2             4.3 g/m2            Pre-plant drench              ns
    Democratic 1                       0.15%:0.2 l/plant        0.22 g/plant        Post-plant drench
    Republic

    German              Lettuce 3      1.5 l/ha                 1.1 kg/ha           Spray (max 3                  lettuce -
    Federal                                                                         applications                  3 weeks
    Republic1           Cucurbits )    0.15%:6 l/m2             6.5 g/m2            Pre-plant drench
                        Tomatoes  )    0.15%:0.2 l/plant        0.22 g/plant        Post-plant drench             ns

    Greece 1            Vegetables     0.15%-0.25%              108-180 g/hl        Seedbed drench
                                       0.15%:100-300            0.22-0.66 g/plant   Drench                        ns
                        Cotton         20-40 ml/kg ml/plant     14.4-28.8 g/kg      Seed treatment

    Hungary 1           Sugar beet     20 ml/kg                 14.4 g/kg           Seed treatment                na
                        Vegetables     0.3-0.4 l/m3             217-289 g/m3        Soil incorporation            vegetables -
                                       0.15-0.25%               108-180 g/hl        Drench                        60 days

    Israel 1            Cucumbers      0.15%                    108 g/hl            Drench                        ns

    Italy 1             Vegetables     10-40 ml/kg              7-29 g/kg           Seed treatment                vegetables -
                                       8-12 ml/m2               5.7-8.7 g/m2        Pre-plant drench              20 days
                                       0.2%:0.1-0.2 l/plant     0.14-0.29 g/plant   Post-plant drench
                                       1.5-3 l/ha               1.1-2.2 kg/ha       Foliar spray

    Jordan 1            Vegetables 4   0.15%                    108 g/hl            Pre- and post-plant           ns
                                                                                    drench

    Malaysia 1          Vegetables 5   0.16%                    116 g/hl            Seedling root soak
                                       0.16%:2 l/m2             2.3 g/m3            Post-plant drench
                                       0.16%                    116 g/hl            Spray (at 5-7 day             ns
                                                                                    intervals)
                                                                                                                                 

    Table 1.  (continued)

                                                                                                                                 
                                       Approved application rate
    Country             Commodity                                                   Applications                  Pre-harvest
                                       formulation containing 72.2%                                               interval
                                       propamocarb hydrochloride a.i.
                                                                                                                                 

    Netherlands 1       Cucumbers)     0.1%:5 l/m2              3.6 g/m2            Pre-plant drench              na
                        Tomatoes )     0.1%:0.25-0.5 l/plant    0.2-0.4 g/plant     Post-plant drench             ns

                        Cauliflower    0.5 l/1000 m2            0.36 g/1000 m2      Seedbed spray

    Peru 1              Vegetables     0.25%:2-4 l/m2           3.6-7.2 g/m2        Seedbed drench
                                       0.15%:6-10 l/m2          6.5-10.8 g/m2       Pre-plant drench              na
                                       0.15-0.2%:6-8 l/m2       6.5-11.6 g/m2       Post-plant drench             ns


    Rumania             Sugar beet )   20 ml/kg                 14.4 g/kg           Seed dressing                 na
                        Cucumbers  )

                        Peppers    )
                        Tomatoes   )   0.15-0.25%               108-180 g/hl        Post-plant drench             ns
                        Cucumbers  )

                        Onions     )   0.15%                    108 g/hl            Spray                         ns
                        Cucumbers  )

    Spain1              Cucumbers      250-300 ml/m3            181-217 g/m2        Soil incorporation            cucumbers
                                       0.25%:6 l/m2             10.8 g/m2           Post-seeding drench           3 weeks
                                       5-7.5 ml/m2              3.6-5.4 g/m2        Seedbed drench
                                       0.15%:100 ml/plant       0.11 g/plant        Post-plant drench

                        Strawberries   0.3-0.5%                 216-360 g/hl        Preplant dip                  strawberries -
                                       0.15%:100 ml/plant       0.11 g/plant        Post-plant drench             6 weeks

    Switzerland 1       Vegetables     2-20 ml/kg               1.44-14.4 g/kg      seed treatment                na
                                       0.25%:2-4 l/m3           3.6-7.2 g/m2        Post-seeding drench
                                       0.15%:5-10 l/m2          5.4-10.8 g/m2       Post-pricking-out drench
                                                                                                                                 

    Table 1.  (continued)

                                                                                                                                 
                                       Approved application rate
    Country             Commodity                                                   Applications                  Pre-harvest
                                       formulation containing 72.2%                                               interval
                                       propamocarb hydrochloride a.i.
                                                                                                                                 

                        Lettuce        0.15%:3-6 l/m2           3.2-6.5 g/m2        Post-pricking-out drench
                                       0.15%:5-10 l/m2          3.2-6.5 g/m2        Pre-plant drench
                                       1.5-2 l/ha (0.15%)       1.08-1.44 kg/ha     Spray, 2 weeks after          lettuce -
                                                                                    planting                      3 weeks
                                                                                    (at 2 week intervals)

    Thailand            Tomatoes )
                        onions   )     0.15-0.25%               108-180 g/hl        Seedbed drench                na

    United 1            Edible         10 ml/m2                 7.2 g/m2            Seedbed drench
    Kingdom             crops 6        0.4 l/m3                 289 g/m3            Compost incorporation         edible crops -
                                       0.15-0.2%:0.1 l/plant    0.11-0.14 g/plant   Drench                        14 days

                                                                                                                                 

    Notes:  na = not applicable
            ns = not specified

    1   Approval for ornamentals not included
    2   Approval includes use in greenhouses
    3   Not approved under glass
    4   Cucumbers, tomatoes and watermelons
    5   Tomatoes, cabbage, cucumbers, lettuce and watermelons
    6   Brassicas, celery, cucumbers, leek, marrow, melons, onions, peppers, spinach, strawberries and tomatoes
    
    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Residues of propamocarb have been determined in a variety of
    plant products following soil incorporation, soil drench, seed
    dressing and foliar treatments. Trials have been carried out by
    Schering AG in many countries representing different climatic
    conditions on a wide range of food crops. All residues in the
    supervised trials are expressed as propamocarb hydrochloride.

         Detailed lists of the residues resulting from supervised trials
    are presented in Tables 2 to 6. The commodities analysed are grouped
    according to the classification adopted by the CCPR.

         Results from trials are underlined when they are in accordance or
    approximately in accordance with approved uses and (when applicable)
    with the recommended withholding periods in the country in which the
    trial was performed.

    Root and tuber vegetables, A01.0100 (Table 2)

    Red and sugar beets.  Mature red and sugar beet roots were analysed
    for residues of propamocarb after seed treatment at 10.89 g/kg seed.
    Red beets were treated additionally with a 0.18% drench immediately
    after seeding. Residues at harvest were below the limit of
    determination (<0.2 mg/kg and <0.05 mg/kg for red and sugar beets
    respectively.

    Radishes.  Radishes grown as second crop following tulip cultivation
    under glass in soils treated with 5.2 g/m2 and 11.2 g/m2 a.i. showed
    residues of 0.8 and <0.05 mg/kg after 86 and 99 days, respectively.
    Radishes treated first with a seed dressing (7.2 g/kg seed) and later
    with two drench treatments at high dosage rates (2 × 36.1 kg/ha or
    2 × 54.2 kg/ha) resulted in relatively high residues of 9.1 and
    7.6 mg/kg after 9 - 14 days and 3.7 and 6.6 mg/kg after 18 - 21 days.
    When the drench treatments were at lower rates (0.65 or 0.72 kg/ha) or
    the radishes were sprayed at 0.72 kg/ha, the residues ranged from 3.4
    to 0.2 mg/kg after 9 - 14 days and from 2.8 to <0.2 mg/kg after
    18 - 21 days.

    Bulb vegetables, A01.0200 (Table 2)

    Leeks  Leeks were sprayed after transplanting with 0.11%
    propamocarb. The residue level 25 days after treatment was 4.1 mg/kg.

    Leafy vegetables (except brassica vegetables), A01.0300 (Table 3)

    Endive.  Following spray application with 0.11% propamocarb
    hydrochloride, residues in endive ranged from 0.4 mg/kg to 2.3 mg/kg
    after 15 days, and from 0.5 to 0.6 mg/kg after 25 days.



        Table 2.  Supervised residue trials with propamocarb on root, tuber and bulb vegetables

                                                                                                                                            
                                      Application method and rate (a.i.)             Residues (mg/kg) / Days after final application
                                                                                                                                            
    Commodity    Country       Year   Seed     Soil in- Drench    Spray
                                      dressing corp.    %         %           0     9-14  18-21  25-30  39-40  50   80-90   90-100   > 100
                                      g/kg     g/m2     (kg/ha)   (kg/ha)
                                                                                                                                            

    Red Beet     Switzerland   1979   10.8                                                                                           <0.2
                                                        0.18                                                                         <0.2

    Sugar Beet   Finland       1979   10.8                                                                                           <0.05

    Radish       German        1976             5.2                                                                 0.8
                 Federal                       11.2                                                                         <0.05
                 Republic

                               1979   7.2               (2x36.1)              61    9.1   3.7
                                                        (0.65)                            2.8                  0.4
                                                        (2x0.65)                                        1.1
                                      7.2               (0.72)                 1.8  0.2

                               1980   7.2               (2x54.2)               3.7  0.4  <0.2
                                      7.2               (2x54.2)              39    7.6   6.6
                                      7.2                         (0.72)      25    3.4   0.2
                                      7.2                         (0.72)      48    0.3          <0.2

    Leek         Italy         1981                                0.11                           4.1
                                                                                                                                            

    Table 3  Supervised residue trials with propamocarb on leafy vegetables (except brassica)

                                                                                                                                              
                                     Application method and rate (a.i)                   Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity  Country       Year    Soil            Drench  Spray
                                     incorporation                           0    4-7  14-15  17-21  24-33  47-50   60-63  70     80-83   > 100
                                     g/m     (g/m2)  g/m2    % (kg/ha)
                                                                                                                                              

    Endive     Italy         1981                            0.11                      0.4           0.6
                                                             0.11                      2.3           0.5

    Lettuce    German        1976    ( 5.2)                                                                                             <0.05
               Federal               ( 7.5)                                                                                              0.5
               Republic              (11.2)                                                                                              0.05
               (GFR)

               Netherlands   1977                            2x0.04 (0.36)                           4.0
                                                             0.07+0.04                               0.2

               France        1977                            2x0.04                    4.0           2.8
                                                             0.07+0.04                 5.4           4.1
               Belgium       1977                            2x0.04                                  0.3
                                                             0.07+0.04                               0.2

               France        1977    180                                                                                         2.5
                                     180                     0.12 (1.16)                                    1.5
                                                             2x0.12 (1.16)                                          0.15
                                                             3x0.12 (1.16)                                  0.05

               GFR           1977                    2.2                                                    0.5
                                                     2.2                                                    0.05
                                                             3x0.07 (0.87)                     0.75
                                                     5.4                                                                   0.05
                                                     5.4     2x0.07 (0.87)                           0.1

               Austria       1977                    7.2*    (3x1.81+1x0.65)*                 13
                                                             (3x0.43)*                         1.2
                                                             (4x0.43)*            54
                                                                                                                                              

    Table 3 (continued)

                                                                                                                                              
                                Application method and rate (a.i)                    Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity  Country   Year   Soil            Drench   Spray
                                incorporation                                0    4-7  14-15  17-21  24-33  47-50   60-63  70   80-83 > 100
                                g/m    (g/m2)   g/m2     % (kg/ha)
                                                                                                                                              

               GFR       1977                            (3x1.44)            26    6.8  4.8    1

    Lettuce    GFR       1977                            3x0.04(0.36-0.54)              7      4.5    2.5
                                                         3x0.07(0.72-1.08)             17      8.5    4
                                                         3x0.11(1.08-1.62)              9.5    5.5    2
                                                         3x0.14(1.44-2.17)             30     17      6

               GFR       1977                            3x0.07 (1.44)                 23     7.2
               GFR       1978                            3x0.07 (1.08)*      62   43   11.1   2.5

               Austria   1978                   7.2*     (1x1.44)*                            8
                                                7.2*     (2x1.44)*                                    6
                                                7.2*     (3x1.44)*                 6          3
                                                7.2*     (4x1.44)*                13                 13
                                                         (2x1.44)*                            3
                                                         (3x1.44)*                            7
                                                         (2x1.44)*                            2
                                                                                                                                              

    Table 3 (continued)

                                                                                                                                              
                                   Application method and rate (a.i)                    Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country   Year     Soil      Drench    Spray
                                   incorporation                               0       4-7     9-15    17-23    24-34   39-40   78-83   90-93
                                   (g/m3)    g/m2      % (kg/ha)
                                                                                                                                              

    Lettuce     GFR       1978                         (3 x 1.08)*             45.4    21.7    19.7    2.6      6.1
                                                       (3 x 1.08)*             30.9    14.5     6.8    4.9      1.3
                                                       (3 x 1.08)*             49.2    20.8     5.3    1.5

                GFR       1978                         (3 x 1.08)              66.2    10.7     1.1    0.4      0.4
                                                       (3 x 1.08)              35.3     6.3     2.3    0.4

                GFR       1978                         (3 x 1.08)              44.3    10.4     7.7    1.6
                                                       (1x0.72+3x1.08)         43.3     6.3     0.9    0.4
                UK        1978               6.25                                                                       8.6
                                                       4x0.07                                                    1.1

                France    1977     108                                                                                          2.2
                                   144                                                                                          3.2
                                   180                                                                                          3.1


                GFR       1978                         (3 x 1.08)*                     11.3    7.5      8.7      1.5

                Denmark   1978               7.2*                                                                6.3
                                                       0.07 (1.81)*                                             <0.1
                                                       0.07 (1.81)                                               1.1
                                             7.2*                                                                       2.6
                                                       1x0.07 (1.81)*                                            0.5
                                                       2x0.07 (1.81)*                                            2.6
                                                       3x0.07 (1.81)*                                  15
                                                                                                                                              

    Table 3 (continued)

                                                                                                                                              
                                   Application method and rate (a.i)                    Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country   Year     Soil      Drench    Spray
                                   incorporation                               0       4-7     9-15    17-23    24-34   39-40   78-83   90-93
                                   (g/m3)    g/m2      % (kg/ha)
                                                                                                                                              

                France    1978     180*                                                                                         0.6
                                   217*                                                                                         0.1-0.2
                                   253*                                                                                         0.3
                          1979     217*                                                                                         0.6     0.1

                GFR       1978                         (3 x 1.08)*             62      43      38      19
                          1979                         (3 x 1.08)*             50              18       7.4      7.3
                                                       (3 x 1.08)*             38              12       6.7      2.7
                                                       (3 x 1.08)*             58      25      17      11
                                                       (3 x 1.08)*             49              39      25       14
                                                       (1x0.72+3x1.08)         70      42      18      13
                                                                                                                                              

    Table 3 (continued)

                                                                                                                                              
                                 Application method and rate (a.i)                   Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country   Year   Soil     Drench      Spray
                                 incorp.  g/m2                        4-8    9-15  17-23 24-35  37-40  42-50  55-63  70    73-83  90-93  >100
                                 g/m3     (g/plant)   % (kg/ha)
                                                                                                                                              

    Lettuce     Austria   1979            9+(0.2)*                                                     1.8
                                          9+(2x0.2)*                                1.7
                                                      (1x1.44)*              15    11    1.6
                                                      (1x1.44)*              55    30    3
                                          0.15*       (3x1.44)*       18      9.7
                                                      (3x1.5)*               12     7.2
                                                      (3x1.5)*                8.3   4.4
                                          5.4*        (3x1.5)*               36    27
                                          5.4*        (3x1.5)*               28    21
                                                      (3x1.44)*              20    11
                                                      (2x1.44)*              18
                                                      (3x1.44)*       21            8

                Italy     1980            10.8                                                  3.9                  5

                Denmark   1980            7.2*                               1.4   6.3   5.1
                                          7.2*                               4.3   4.6   3.5
                                          7.2*                               3.1   3.3   2.3
                                          7.2*                                     5.3   2.3

                UK        1981   210                                                                                       0.4
                                 280                                                                                       0.1-0.5
                                 420                                                                                       1
                                 560                                                                                       1
                                 210                                                                                                      1.6
                                 210                                                                                                      0.7
                                 280                                                                                                      0.7

    Lettuce     France    1981   182                                                                                       0.1
                                 217                                                                   0.1
                                                                                                                                              

    Table 3 (continued)

                                                                                                                                              
                                 Application method and rate (a.i)                   Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country   Year   Soil     Drench      Spray
                                 incorp.  g/m2                        4-8    9-15  17-23 24-35  37-40  42-50  55-63  70    73-83  90-93  >100
                                 g/m3     (g/plant)   % (kg/ha)
                                                                                                                                              

                GFR       1981   217                                                             0.3   <0.1   <0.1
                                 217                                                     0.1           <0.1   <0.1
                                          7.2         (1x1.08)               15    2.2   0.1    <0.1
                                 217                                                                          <0.1         <0.1   <0.1

                Denmark   1979                        (1x1.4)*               11
                                 1.4*                                                    0.2
                                                      (2x1.4)*                9.3
                                                      (1x1.4)*                      2
                                 1.4*                                                    0.2     0.3   <0.1
                                                      (1x1.4)*               34    14
                                                                                                                                              
                                            Application method and rate (a.i.)      Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity      Country       Year       Seed           Spray
                                            dressing                                0         7         10-11     14        21-22     28-30
                                            g/kg           kg/ha
                                                                                                                                              

    Spinach        German        1978       14.4           2 x 0.72                 19        2.2                 3.1        2.3
                   Federal
                   Republic      1979       14.4           2 x 0.72                 33                   9.7                 6.9       3.7
                                            14.4           2 x 0.72                 71                  16                   3.8       2.0
                                            14.4           2 x 0.72                 42                  22                   6.5       6.0
                                 1980       14.4           2 x 0.72                 36                   1.5                <0.2      <0.2
                                                                                                                                              

    *  Application in greenhouses

    Table 4.  Supervised residue trials with propamocarb on brassica leafy and stem vegetables

                                                                                                                                                
                                         Application method and rate (a.i.)        Residues (mg/kg) / Days after final application
                                                                                                                                                
    Commodity       Country     Year     Soil           Drench     Spray
                                         incorporation             %               12-40     56-76    88-98   118-147    170-174    196-231
                                         g/m3           mg/plant   (kg/ha)
                                                                                                                                                

    Brussels        UK          1978                      108                                                                        <0.2
    sprouts                                               217                                                                         0.8
                                                          866                                                                         0.6

                    1979                                  108                                                                        <0.05
                                                          217                                                                        <0.05
                                                          108                                                                         0.13
                                                          217                                                                         0.05
                                                          108                                                                        <0.05
                                                          217                                                                        <0.05
                                                                   2 x 0.11        2.2

                                                          144                                                 <0.05
                                                          144                                                 <0.05                  <0.05
                                                          144                                                            <0.05
                                                          144                                                            <0.05

    Cabbage         UK          1978                      181                                                 <0.05

                                1979                      108                               <0.02
                                                          217                               <0.02
                                                          108                                                  0.02
                                                          217                                                  0.06

    Cauliflower     UK          1978     217                                       0.05

                                1979                  2 x 108                               <0.05
                                                      1 x 108                               <0.05
                                                      2 x 217                               <0.05
                                                      1 x 217                               <0.05
                                                                                                                                                

    Table 4.  (continued)

                                                                                                                                                
                                         Application method and rate (a.i.)        Residues (mg/kg) / Days after final application
                                                                                                                                                
    Commodity       Country     Year     Soil           Drench     Spray
                                         incorporation             %               12-40     56-76    88-98   118-147    170-174    196-231
                                         g/m3           mg/plant   (kg/ha)
                                                                                                                                                

                                                      2 x 108                               <0.05
                                                      1 x 108                               <0.05
                                                      2 x 217                               <0.05
                                                      1 x 217                               <0.05
                    Netherlands 1982                               (2 x 1.08)     <0.1
                                                                   (2 x 2.17)      0.1

                                1983                               (1-3x2.17)     <0.1
                                                                   (1 x 3.61)     <0.1
                                                                   (2 x 3.61)      0.17
                                                                   (3 x 3.61)      0.14

    Celery          UK          1978                  2 x 250                                         1.1
                                                      3 x 250                                         0.1
                                                      3 x 250                                         0.2

                    Italy       1981                               0.11            2.7
                                                                                                                                                

    Table 5.  Supervised residue trials with propamocarb on fruiting vegetables - edible peel

                                                                                                                                              
                                   Application method and rate (a.i.)          Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country     Year   Soil            Drench          Spray
                                   incorporation   mg/plant        %           0-3      4-7    9-14  19-21  26-38 40-62  68-79  82-97  140
                                   g/m3            (g/m2)          (kg/ha)
                                                                                                                                              

    Cucumbers   Sweden      1977                   542                                                      1.4
                                                   361                                                      1.5
                                                   181                                                      1.1

                Spain       1978                   361                                                             0.3
                                                   2 x 181                                                         0.3
                                                   2 x 361                                                         0.8
                                                   722+361                                                        <0.1
                                                   181                                                                   <0.1
                                                   181+361                                                        <0.1
                                                   2 x 361                                                        <0.1

                Sweden      1978                   2 x 361                              2.0    0.9   0.6    0.7

                Denmark     1978                   5 x 181                                     1.3          0.8    0.4

                GFR         1979                   (4.3+0.2)                                                0.4   <0.1
                                                   (6.5+0.2)                                               <0.1   <0.1

                                                   (8.7+0.3)                                               <0.1   <0.1

                Israel      1979                   361                                                                                <0.05

                Austria     1979                   (9)+217                                                         1.8
                                                   (9)+2x217                                   1.7

                Switzerland 1981                   (2x9)+361+722                                     0.6
                                                   (2x9)+361+2x722             0.8      0.4    0.4   0.2
                                                   (2x9)+361+144   0.07        1.4      1.2    0.5   0.5
                                                                                                                                              

    Table 5.  (continued)

                                                                                                                                              
                                   Application method and rate (a.i.)          Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country     Year   Soil            Drench          Spray
                                   incorporation   mg/plant        %           0-3      4-7    9-14  19-21  26-38 40-62  68-79  82-97  140
                                   g/m3            (g/m2)          (kg/ha)
                                                                                                                                              

                Greece      1981                                   3x0.14      1.7             1.0

                Netherlands 1983                   90 DI*                      0.1-0.8  0.8    0.3   0.1
                                                   180 DI                      0.5-0.8  1.9    0.7   0.1
                                                   720 DI                      0.1-3.3  3.5    1.1   0.1

    Cucumbers   GFR         1983                                   (8x2.17)    0.9-1.5  0.6    0.5
                                                                   (8x2.17)    0.8-1.2  0.9    0.8

    Peppers     GFR         1977                   32+108                                                          0.1
                                                   65+217                                                          0.2
                                                   130+433                                                         0.25

                France      1978   181             4x217-1083      0.22(dip)                                      <0.2
                                                   4x217-1083      0.22(dip)                                      <0.2
                                                   5x217-1083                                                     <0.2

                Italy       1980                   (10.8)                                                                             <0.05

                Netherlands 1983                   108NFT**                   <0.02    <0.01   0.1   0.2
                                                   217NFT                     <0.01     0.2    0.4   0.9
                                                   866 NFT                     0.2-0.5  0.3    0.5   1.7
                                                                                                                                              

    Table 5.  (continued)

                                                                                                                                              
                                   Application method and rate (a.i)           Residues (mg/kg) / Days after final application
                                                                                                                                              
    Commodity   Country       Year              Drench
                                                mg/plant                 0-3       4-7    10-14   19-21  26-38   40-62   68-79   82-97  101-119
                                                (g/m2)
                                                                                                                                              
    Tomatoes    GFR           1978              (3.25)                                                                                   <0.05
                                                (2x3.25)                                                                <0.05
                                                (2x3.25)+217                                                            <0.05

                              1979              (4.33)+144                                                       0.10    0.08    0.06
                                                (6.50+0.54)                                                     <0.05   <0.05   <0.05

                Denmark       1979              108                                                              0.09    0.05

                GFR           1979              (8.66+0.90)                                             <0.05    0.26    0.17


                Italy         1980              722                                                                             <0.1      0.23
                                                1444                                                                             0.29    <0.1
                                                (10.8)                                                                  <0.1              1.9
                                                (10.8)                                                                   0.57            <0.1

                Netherlands   1983              90 DI*                   0.05     <0.05  <0.05   <0.05
                                                180 DI                   0.06     <0.05   0.06   <0.05
                                                720 DI                   0.05-0.4  0.2    0.2     0.4

                                                108 NFT**               <0.05     <0.05  <0.05    0.05
                                                217 NFT                 <0.05      0.06   0.3     0.3
                                                866 NFT                 <0.05      0.8    0.5     0.6
                                                                                                                                              

    Notes:      * DI = Drip Irrigation
                * NFT = Nutrient Film Technique

    Table 6.  Supervised residue trials with propamocarb on miscellaneous crops

                                                                                                                                              
                                    Application method and rate (a..i)                 Residues (mg/ks) / Days after final application
                                                                                                                                              
    Commodity      Country   Year   Soil       Seed      Drench   Spray
                                    treatment  treatment mg/plant mg/plant  36-39   60    70-78   101-105  126-132  230-272  278-305  328-370
                                    g/m2       g/kg      (%)
                                                                                                                                              

    Melons         Italy     1980                          722              <0.05
                                                          1444              <0.05

    Pumpkins       Italy     1980                          722               0.08
                                                          1444               0.21
                                    10.8                                                  <0.05   <0.05

    Apples         Italy     1981   2x8.7                                                 <0.05            <0.05

    Strawberries   GFR       1977/78                              722                                                        <0.05
                                                                  2x361                                             <0.05
                                                                  722+361                                           <0.05

                   GFR       1977/78                              940                                                        <0.05
                                                                  2x940                                             <0.05
                                                                  2x470                                             <0.05
                                                                  722                                                                  0.1
                                                                  2x361                                                               <0.05
                                                                  2x722                                                               <0.05

                   Belgium   1979/80                       722                                    <0.01     0.02
                                                           722                                                      <0.01    <0.01
                                                           722                                                      <0.01    <0.01

                   Italy     1980                          722                      0.43
                                                          1444                      1.3

                   UK        1978-80                  (2x0.14)                                                      <0.02
                                                      (2x0.29)                                                      <0.02
                                                                                                                                              

    Table 6.  (continued)

                                                                                                                                              
                                    Application method and rate (a..i)                 Residues (mg/ks) / Days after final application
                                                                                                                                              
    Commodity      Country   Year   Soil       Seed      Drench   Spray
                                    treatment  treatment mg/plant mg/plant  36-39   60    70-78   101-105  126-132  230-272  278-305  328-370
                                    g/m2       g/kg      (%)
                                                                                                                                              

    Rapeseed       GFR       1980/81           7.2                                                                  <0.05    <0.05
                                               7.2                                                                  <0.05    <0.05
                                               7.2                                                                  <0.05    <0.05    <0.05
                                                                                                                                              
    
    Lettuce.  A number of different application methods are used in
    lettuce cultivation with spray applications always giving the highest
    residue levels. Multiple sprayings of propamocarb in the field at
    1.1 kg/ha (the approved rate for the Federal Republic of Germany,
    except in greenhouses) resulted in residue levels after 21 days (the
    recommended withholding period) ranging from 0.4 mg/kg to 13 mg/kg.
    When spray applications were conducted under glass, residues 21 days
    after final application increased up to 25 mg/kg following 3 sprays at
    a rate of 1.1 kg/ha and up to 11 mg/kg at a rate of 1.44 kg/ha (the
    approved rate in Austria).

         Soil incorporation of propamocarb HC1 gave considerably lower
    residues, up to 3.2 mg/kg after 80 days.

         Soil drench applications also resulted in lower residues than
    spray treatments, up to 6.3 mg/kg 18 days after drenching.

    Spinach.  Combined seed dressing (14.4 g/kg seed) and spray
    applications (2 × 0.72 kg/ha) to spinach gave residues on day 0 after
    final application of 19-71 mg/kg; days 10-11, 1.5-22 mg/kg; days
    21/22, <0.2-6.9 mg/kg and days 28/30, <0.2-6.0 mg/kg.

    Brassica (cole) leafy vegetables, A01.0400 (Table 4)

    Brussels sprouts.  Drench application to Brussels sprouts at rates
    up to 866 mg/plant gave residues ranging from <0.05 mg/kg to
    0.8 mg/kg, 196 - 231 days after treatment.

         Two spray treatments with 0.11% propamocarb hydrochloride
    resulted in a residue of 2.2 mg/kg, 28 days after the final
    application.

    Cabbage.  In cabbage treated with 108 - 217 mg/plant by drench, only
    minimal residues (<0.02 mg/kg to 0.06 mg/kg) could be found 65 - 118
    days after application.

    Cauliflower.  Soil incorporation or drench treatments of
    cauliflowers resulted in residues near or below the limit of
    determination (0.05 mg/kg) at harvest. Multiple spray applications up
    to 3.6 kg/ha gave a maximum residue of 0.17 mg/kg, 26 days after the
    final application.

    Stem vegetables, A01.0500 (Table 4)

    Celery.  Multiple drench applications to celery at 250 mg/plant
    resulted in a maximum residue of 1.1 mg/kg, 98 days after the last
    treatment.

         A single spray application at 0.11% propamocarb hydrochloride
    resulted in a residue of 2.7 mg/kg, 25 days after treatment.

    Fruiting vegetables - edible peel, A01.0700 (Table 5)

    Cucumbers.  Multiple drench applications to cucumbers at rates up to
    722 mg/plant or 8.7 g/m2 gave the following maximum residue levels:
    0-3 days, 1.4 mg/kg; 4-7 days, 2.0 mg/kg; 9-14 days, 1.7 mg/kg;
    19-21 days, 0.6 mg/kg; 26-38 days, 1.5 mg/kg and 40-62 days,
    1.8 mg/kg.

         Multiple spray treatments with 0.14% propamocarb hydrochloride
    resulted in a residue of 1.7 mg/kg three days after the final
    application and 1.0 mg/kg 10 days after the last spraying. Eight
    sprayings with 2.17 kg a.i./ha gave the following residue levels:
    0-3 days, 0.8-1.5 mg/kg; 4-7 days, 0.6-0.9 mg/kg; 9-14 days,
    0.5-0.8 mg/kg.

         Drip irrigation at 90 mg/plant (the highest rate recommended for
    disease control) gave residues of 0.1-0.8 mg/kg at 3 days, 0.8 mg/kg
    at 7 days, 0.3 mg/kg at 14 days and 0.1 mg/kg at 21 days after
    application.

    Peppers.  Multiple drench treatments of peppers up to 1083 mg/plant
    results in low residue levels of 0.1-0.25 mg/kg, 40-62 days after
    application. In peppers treated with propamocarb using the nutrient
    film technique at 108 mg/plant (the highest rate recommended for
    disease control) residues were <0.01-0.2 mg/kg.

    Tomatoes.  Multiple drench applications to tomatoes at rates up to
    10.8 g/m2 or 1444 mg/plant gave residues of <0.05-0.57 mg/kg at
    68-79 days after the final application and <0.05-1.9 mg/kg at
    101-119 days.

         Residues observed in trials using 90 mg/plant as a drip
    irrigation or 108 mg/plant in the nutrient film technique (the highest
    rates recommended for disease control) did not exceed 0.05 mg/kg
    during the 21 day pre-harvest interval.

    Fruiting vegetables - inedible peel, A01.0800 (Table 6)

    Melons.  Residues in melons treated by drenching with 722 or
    1444 mg/plant were below the limit of determination (<0.05 mg/kg),
    36 days later at harvest.

    Pumpkins.  Soil treatment of pumpkins with 10.8 g/m2 gave no
    detectable residues (>0.05 mg/kg), 70 days after application.

         Drenching with 1444 mg/plant resulted in a residue of 0.21 mg/kg
    39 days later at harvest.

    Pome fruit, A02.1000 (Table 6)

    Apples.  In apples treated twice with 8.7 g/m2, residues could not
    be determined (<0.05 mg/kg) 78 days after application.

    Small fruits and berries, A02.1200 (Table 6)

    Strawberries.  Spray applications to strawberries at rates up to
    2 × 940 mg/plant did not lead to residues exceeding 0.1 mg/kg after
    230-370 days.

         Drench treatments with 722 and 1444 mg/plant resulted in residues
    of 0.43 and 1.3 mg/kg, respectively, 60 days after application. In
    another trial (UK, 1978-1980) no residues (<0.02 mg/kg) could be
    determined 271 days after drench application.

    Oilseed, A05.2000 (Table 6)

    Rapeseed.  Seed treatment of rapeseed with 7.2 g/kg propamocarb
    hydrochloride did not give any detectable residues (<0.05 mg/kg) at
    harvest.

    FATE OF RESIDUES

    General

         Studies have been carried out on lettuce and tobacco, soil and
    water. For discussions on the metabolic fate of propamocarb in the
    rat, see "Biochemical aspects" in the evaluation for ADI. No feeding
    studies have been performed on cattle or poultry as no uses of
    propamocarb on crops used for animal feedingstuffs have been approved.
    Studies have also been made on bioaccumulation in fish.

    In soil

         The behaviour of propamocarb hydrochloride in soils was
    investigated by studies of leaching, tested by column leaching and
    adsorption/desorption experiments; dissipation and degradation in a
    variety of soil types and under different conditions in the laboratory
    and field; the effect on soil microorganisms; uptake by rotational
    crops.

    Leaching.  Studies show that the leaching of propamocarb
    hydrochloride is very dependent on the soil type. The migration of
    propamocarb hydrochloride residues to deeper soil layers was tested by
    column leaching and adsorption/desorption experiments on the following
    German standard soils:

                        pH             organic carbon    clay + silt (%)
                                       (%)               (<0.02 mm)
                                                                         

    2.1 loamy sand      5.5-7.5        0.25-0.75         <10

    2.2 loamy sand      5.5-7.5        2-3               10-20

    2.3 sandy loam      5.5-7.5        0.5-1.5           20-30

         No propamocarb or degradation products were found in the
    leachates from columns filled with standard soils 2.1, 2.2 or 2.3
    after irrigation with 200 mm of artificial rain water. Examination of
    some columns, however, revealed that the fungicide was not entirely
    immobile, since the bulk of the material had moved to a depth of
    8 - 20 cm in standard soils 2.1 and 2.2. This is consistent with the
    Freundlich adsorption constants determined for standard soil 2.2
    (5.83) and a river bottom sediment (1.26). (Ottnad, 1978a; Brühl,
    1979d; Brühl and Celorio, 1979a).

         Leaching tests on 4 different soils including German standard
    soils 2.1 and 2.2, conducted according to EPA guidelines, showed that
    even extended irrigation with 600 mm of water over a period of about 6
    days did not cause penetration of most soil columns used except those
    consisting of standard soil 2.1, from which 50 to 60% of the applied
    ingredient was found in the leachate (Brühl, 1978a).

         After aging for 30 days in standard soil 2.2, most of the applied
    propamocarb hydrochloride had been mineralized. Upon irrigation with
    12.5 mm water for 45 days, only 10-15% of the original material was
    recovered, the main part being absorbed by the first 5 cm of the
    columns. Less than 2% of the fungicide was found in the leachate.
    Under the same conditions the behaviour of propamocarb hydrochloride
    in standard soil 2.3 was quite different. Only about 20% of the parent
    compound was eventually mineralized, 38 to 48% appeared in the
    leachate and the rest was evenly distributed over the entire soil
    column. This is somewhat surprising since another soil (California
    loamy sand), similar in organic carbon content and texture, exhibited
    a much greater adsorption capacity. It seems therefore that besides
    distribution between soil solution and organic matter, other
    mechanisms such as ion exchange exert an important influence on the
    leaching behaviour of propamocarb hydrochloride (Brühl, 1978a; Brühl
    and Celorio, 1979b; Meallier et al., 1983)

    Metabolism.  Laboratory tests under aerobic conditions to determine
    rates of dissipation and metabolic pathways have been performed with a
    variety of soil types. Depending on the microbiological activity of
    the soil samples, adaptation phases of 5 days to 8 weeks were
    necessary before breakdown of propamocarb commenced. After such lag-
    periods, however, dissipation was rapid with half-lives ranging from
    10 to 27 days. This process, which usually followed biphasic first-
    order kinetics, was always accompanied by fast mineralization of the
    molecule as indicated by the high rates of 14CO2-evolution which
    reached as much as 90% after 45 days. (Brühl, 1979b; Brühl and
    Celorio, 1978 and 1980b; Ottnad, 1977c and 1978b). Lowering of the
    ambient temperature from 25° to 15° had no significant effect upon the
    degradation rates (Brühl and Celorio, 1980a).

         Field studies conducted in Germany (Berlin-Frohnau) and the
    United States (Wonder Lake, Illinois; Cantonment, Florida; Blackstone,
    Virginia and Tifton, Georgia) have shown that the laboratory tests
    reflect field behaviour; in all cases the estimated half-lives were in
    the range of 2 to 3 weeks (excluding adaptation phases) (Jenny, 1980a
    and 1980b; Ottnad, 1977a, b).

         Intermediate metabolic products were observed in all tests
    carried out with 14C-labelled material. These compounds occurred in
    small quantities (less than 3% of originally incubated 14C-label),
    indicating that their decomposition was at least as fast as that of
    the parent molecule. Identification of the intermediates was not
    feasible (Brühl, 1979b; Brühl and Celorio, 1978, 1980a, b).

         Studies with sterilized and non-sterilized soil as well as mixed
    populations of soil microorganisms have confirmed that, under aerobic
    conditions, the observed breakdown of propamocarb is brought about by
    microbial action (Iwan, 1979 and 1980).

         Simultaneous application of propamocarb hydrochloride and other
    pesticides to soil had inhibitory as well as stimulating effects on
    aerobic microbial degradation (Fournier et al, 1981).

         Laboratory tests under anaerobic conditions were conducted with
    German standard soil 2.2 and with river bottom sediment. In standard
    soil 2.2, dissipation was very slow with a half-life (calculated
    according to first-order kinetics) of 459 days (Brühl, 1979c).

         A biphasic dissipation process following zero-order kinetics
    (both phases) was observed with river bottom sediment. The half-life
    of propamocarb under these conditions was 55 days. Substantial
    14CO2-evolution, measured up to the 60th days of the experiment,
    indicated that oxidative degradation mechanisms must still have been
    operative during the first phase of decomposition. Intermediate
    metabolic products again occurred in small quantities (up to 4
    compounds, each less than 5% of the originally incubated 14C-label)
    but could not be identified (Brühl and Celorio, 1980c).

    Effect on soil microorganisms.  Studies conducted with freshly
    collected silty clay and sandy loam soils showed that propamocarb
    hydrochloride concentrations of 3 and 30 mg/kg had no significant
    effect on carbon turnover or nitrogen fixation. Sulphur oxidation was
    slightly stimulated at both levels. For protein deamination and
    nitrification, a minor short-lived depression (less than 14 days) was
    noted at 30 mg/kg (Hughes, 1981).

    Uptake by rotational crops.  In a rotational crop study loamy sand
    soil was treated with 14C-labelled propamocarb hydrochloride (3 mg/kg
    dry weight). After aging periods of 30 and 120 days soybeans, sugar
    beets and oats were sown. Crops were harvested at quarter, half and
    full maturity and leaves, stems, roots and fruiting parts were
    analysed separately. In all aerial parts of all crops (both ageing
    periods) residues were less than 0.3 mg/kg. Residues in sugar beets

    were always below the detection limit (0.04 mg/kg). Residues in
    soybeans and oats grown in soil after 30 days ageing appeared somewhat
    higher (up to 0.3 mg/kg) than those in crops grown after an ageing
    period of 120 days. Because the residues were so low no identification
    was possible.

         Analysis of soil samples taken at the same intervals as the crops
    showed rapid degradation of the extractable residues. After 169 days
    in the 30-day-experiment and 245 days in the 120-day-experiment about
    10% remained in the soil as non-extractable material.

         In view of the rapid degradation of propamocarb hydrochloride in
    the soil and the low or undetectable residues in all crops at normal
    harvest, virtually no residues are to be expected in rotational crops
    grown under field conditions in practice (Brühl, 1979a).

    In Plants

         The metabolism of propamocarb hydrochloride in plants was
    investigated in lettuce after spraying and in tobacco treated by
    drenching.

    Metabolism in lettuce.  Studies were conducted to determine the
    nature of the residues after spraying with propamocarb hydrochloride
    with a 3-dimethylamino-[1-14C]-propyl label. Three to nine percent of
    the total residues remained as non-extractable material. Residues in
    the extracts were determined by one- and two-dimensional TLC. 60-85%
    consisted of unchanged parent compound up to 36 days after the last
    application. Up to 17% consisted of five degradation products which
    were not identified. Four of these were more polar and the fifth less
    polar than the parent compound. Further investigations have shown that
    they included artefacts formed during the analysis at the extraction
    stage. It was later shown that the artefacts varied between 3 and 56%
    of the total recovered radiolabelled compounds when no precautions
    were taken. When special care was taken the proportion was 5-17%. It
    was concluded that under optimized analytical conditions only 10-15%
    of the total residue would escape detection because of artificial
    breakdown and formation of non-extractable material. The residue
    analysis of lettuce therefore need only be for the unchanged parent
    compound (Brühl, 1980, 1981a, b).

    Metabolism in tobacco.  Tobacco plants, treated at the 6-8 leaf
    stage by drenching with 300 ml of radiolabelled 0.3% aqueous
    propamocarb hydrochloride solution, took up considerable quantities of
    the fungicide via the root system. Much of this material was
    translocated acropetally to the extent that radioactivity was detected
    in the uppermost leaves and flowers. With respect to distribution, a
    propamocarb hydrochloride concentration gradient of the order of 100:1
    (from bottom to top) was observed, i.e. the residue levels in the
    oldest tobacco leaves were 50 - 200 times higher than those in the
    youngest leaves and the flowers. The meeting was informed that in
    later experiments, TLC and GC/MS analysis of the plant extracts showed

    that all residues consisted of the unchanged parent compound. Curing
    of the tobacco leaves had no effect on the residue composition. Only
    about 1% or less of the radioactivity in the tobacco plants was 
    non-extractable by the methods employed (Brühl, 1978b).

         The distribution of propamocarb in tobacco plants after uptake
    via the roots indicates that the fungicide is partly systemic.

         A possible explanation for the lack of metabolic conversion in
    the plant species investigated may be that phase-I reactions
    (detoxifying processes) are not needed, since propamocarb has little
    phytotoxic effect. Phase-II reactions (conjugation), usually aimed at
    enhanced water solubility of xenobiotics and thus better storage in
    cell vacuoles, appear equally unnecessary in view of the virtually
    unlimited water solubility of the compound.

    In animals

         No feeding studies have been performed on cattle or poultry as no
    uses of propamocarb on crops used for feeding of animals have been
    approved.

    In fish

         Bluegill fish (Lepomis macrochirus) were exposed to 0.1 mg/l of
    [14C]-propamocarb hydrochloride in a flow-through system for 28 days
    followed by a 14-day depuration period. [14C]-propamocarb
    hydrochloride equivalents in fillet tissue ranged from less than
    0.5 mg/kg at 10 days to a maximum of 1.70 mg/kg at 14 days. In offal
    tissue, residues ranged from 1.83 mg/kg at day 1 to 3.42 mg/kg at day
    7.

         Channel catfish (Ictaluras punctatus) were exposed to water
    containing soil, into which had been incorporated [14C]-propamocarb
    hydrochloride at 3.0 mg/kg, in a static system for 28 days followed by
    a 14-day depuration period. The level of radio-carbon in the hydrosoil
    decreased from 2.60 mg/kg after one day to 1.28 mg/kg after 28 days,
    whilst levels in the water ranged from 0.013 mg/l at day 1 to
    0.029 mg/l at day 28. [14C]-propamocarb hydrochloride equivalents in
    fillet tissue ranged from 0.098 mg/kg at day 1 to 1.16 mg/kg at day
    28, and in offal tissue from 0.16 mg/kg at day 1 to 1.08 mg/kg at day
    28.

         In both species, radioactivity was rapidly lost from tissues when
    the fish were transferred to untreated water or water/soil systems.
    Bioconcentration factors for fillet and offal tissues were 1.5 and 3.0
    for bluegill and 39.9 and 43.0 for channel catfish, respectively. The
    biological half-life of radioactive residues was less than seven days
    in all cases (Gray and Knowles, 1980).

         Both bluegills and channel catfish received intraperitoneal
    injections of [14C]-propamocarb hydrochloride at a level of
    2.25 mg/kg. Elimination of radioactivity was rapid in both species
    with more than 77% of the dose present in the water within 24 hours.
    Compounds from this water were separated by TLC. Besides unchanged
    propamocarb, which was the main compound, they included three unknown
    metabolites. Residues in the fish 24 hours after administration were
    highest in the bile in both species. In both fillets and offals
    unchanged propamocarb was the main compound and three metabolites were
    also present. Small amounts of a compound which co-chromatographed
    with 3-dimethylaminopropylamine were also observed (Gray and Knowles,
    1981).

    In water

    Hydrolysis.  Hydrolytic breakdown of propamocarb hydrochloride is a
    base-catalyzed process which proceeds at extraordinarily low rates.
    Even at pH 14 at 25°C, a half-life of about 5 days was measured. The
    temperature dependence of the rate constant strictly followed the
    Arrhenius equation with the activation energy EA amounting to
    17.57 kcal/mol. Assuming pure base catalysis, the rate constants and
    half-lives shown in Table 7 were obtained by extrapolation to pH 9, 7
    and 5 at 25°C.

    Table 7.  Rate constants and half-lives of propamocarb in water

                                                                

    pH             k1 (min-1)                  t1/2 (years)
                                                                

    9              1.05 x 10-9                 1.26 x 103

    7              1.05 x 10-11                1.26 x 105

    5              1.05 x 10-13                1.26 x 107
                                                                


    Propamocarb hydrochloride is stable in acid aqueous solution. No
    indication of hydrolysis was detected after exposure to pH 1 at 70°C
    for 3 days (Repenthin, 1976).

    Photolysis.  Following 92 hours of irradiation at wavelengths above
    290 nm and a light intensity of 2250 Jm-2 sec-1, the decrease of the
    initial propamocarb hydrochloride concentration in aqueous solution
    was no greater than in corresponding non-irradiated controls. This is
    to be expected, since the compound does not absorb light energy from
    the environmentally relevant part of the spectrum. The addition of
    acetone did not produce any measurable photosensitising effect (Klehr,
    1978). Additional studies have shown that the observed decrease of the
    propamocarb hydrochloride concentration in irradiated as well as 
    non-irradiated solutions was due to microbial activity (Klehr, 1980).

    Biological decomposition.  In mineral salt solutions containing
    acetate as a carbon source and spiked with a few drops of original
    lake water, propamocarb hydrochloride was rapidly degraded after a
    lag-phase of two weeks. On the 35th day of the test, more than 30% of
    the originally incubated fungicide was mineralized and the amount of
    parent compound had dropped to 3%. Several metabolic products were
    detected in the culture medium. However, as these compounds did not
    accumulate, and therefore occurred only in low quantities (usually
    less than 5%), they could not be identified. In samples lacking an
    additional carbon source, virtually no decomposition of propamocarb
    hydrochloride took place. The most prominent genus amongst the
    microorganisms identified in the culture medium was Pseudomonas
    (Iwan, 1983).

    METHODS OF RESIDUE ANALYSIS

         Analytical methods to detect and quantify propamocarb residues in
    plants, soil and water are designed to determine the unchanged parent
    compound only, because only very small amounts of metabolites have
    been observed in these materials. Residues of propamocarb in plant and
    soil samples are determined by GLC using a thermionic detector
    operating in the nitrogen-specific mode.

         The compound is extracted with 0.1 N-hydrochloric acid, and
    cleaned up by partitioning with chloroform and di-isopropyl ether. The
    free base is quantified by GLC. As the compound is very polar a column
    of carbowax 20M + 0.5% KOH on chromosorb 750 may be used. The limit of
    determination is 0.1 mg/kg in most crops (König and Ottnad, 1977;
    Noach, 1978; Jenny, 1979; Scheuermann, 1983).

         Residues in water are extracted with di-isopropyl ether after the
    addition of sodium hydroxide and measured without further clean-up
    (König and Ottnad, 1977a).

    NATIONAL MAXIMUM RESIDUE LIMITS

         National maximum residue limits from a number of countries were
    reported: (Table 8).

        Table 8.  NATIONAL MAXIMUM RESIDUE LIMITS

                                                                                              

    Country                  Commodity               MRL         Pre-harvest interval
                                                     (mg/kg)     (days)
                                                                                              

    France                   Lettuce                  5.0

                             Cucurbit                 1.5

                             Tomato, pepper,
                             strawberry               0.5

    Federal Republic
    of Germany               Lettuce                 15            21

                             Cucurbit, tomato         0.5

    Hungary                  Vegetables               0.5          60
                                                                   (soil drenching)

    Italy                    Vegetables              10            20

    Netherlands              Fruiting vegetables
                             cauliflower              0.1

    Switzerland              Cucurbits                1.5

                             Lettuce                 10            21
                                                                                              
    
    APPRAISAL

         Propamocarb is a systemic fungicide especially active against
    Oomycetes fungi causing damping-off, root and stem rot, leaf blight,
    fruit rot and downy mildew. It is registered and used in more than 30
    countries.

         Propamocarb is formulated only as 72.2% hydrochloride in aqueous
    solution and all experimental data and application rates are quoted in
    terms of propamocarb hydrochloride. It is used in concentrations
    ranging from 0.1-0.25% for preventive soil drenching or incorporation,
    seed dressing, dipping of bulbs and roots and foliar application.

         When used as a foliage-applied fungicide on fruit and vegetables
    the dosage rates are 1.1-2.2 kg a.i./ha. For soil drenching,
    propamocarb is used at 3.2-11.6 g/sq m or 0.11-0.66 g/plant and for
    soil incorporation at 18.1-28.9 g/cubic m. Used as a seed dressing the
    dosage range is from 0.36 g/kg (soybeans) to 28.8 g/kg (sugar beets).

         Residues in crops are very dependent on the treatment. Residues
    after drenching, soil incorporation or seed treatment are generally
    low, while residues from foliar application are considerably higher.

         As an example, residues in lettuce, on which propamocarb is
    widely used, after spray application ranged from 0.4 mg/kg to 13 mg/kg
    (25 mg/kg in glass-houses) (3 weeks pre-harvest interval), while soil
    drench applications resulted in residues up to 6.3 mg/kg and soil
    incorporation gave residues of 3.2 mg/kg or lower.

         The meeting noted that residues resulting from spray applications
    are high and, taking the TADS into consideration, it was unable to
    recommend a TMRL for lettuce until more information on GAP and the
    potential intake of propamocarb was available.

         Residues in spinach and leeks after spray applications were of
    the order of 5 mg/kg, while residues in other vegetables, such as
    cauliflower, cucumber and tomato, and also in strawberries after spray
    applications or soil treatments were below 1 mg/kg with few
    exceptions. As the trials on spinach and leeks were not in accordance
    with approved uses, which were available to the meeting, no residue
    limits could be estimated for these crops.

         Metabolism studies have been carried out for propamocarb on
    lettuce and tobacco, in soil and in water, but as propamocarb has not
    been approved for use on crops used as animal feedingstuffs no feeding
    studies have been carried out.

         Laboratory as well as field experiments on the metabolism of
    propamocarb in soil have shown that propamocarb is metabolized under
    aerobic conditions with an estimated half-life of the order of 2-3
    weeks, but the breakdown only commences after lag phases from 5 days
    to 8 weeks depending on the micro-biological activity of the soil.

         Intermediate metabolites were observed only in low quantities
    indicating that their decomposition was at least as fast as that of
    the parent compound. Identification of the intermediates was not
    feasible.

         In laboratory tests the dissipation of propamocarb in soil under
    anaerobic conditions was very slow, with an estimated half-life of
    more than one year.

         Leaching studies have been made on different soil types. Leaching
    was observed to some extent in soil types containing up to 20% of clay
    and silt (0.2 mm). After 30 days ageing most of the applied
    propamocarb was mineralized in all soils except in one type in one
    experiment, in which a soil with a higher content of clay and silt was
    used. Only 20% of the propamocarb was mineralized, and a considerable
    proportion of it appeared in the leachate. The leaching behaviour of
    propamocarb seems therefore to be influenced by other factors besides
    particle size and organic matter content.

         The metabolism of propamocarb was investigated after spraying the
    14C-labelled compound on lettuce. Less than 10% remained as 
    non-extractable material 36 days after treatment and 60-85% or more
    consisted of unchanged parent compound. Up to 17% of the extractable
    fraction consisted of degradation products, which were later shown to
    be mainly formed at the extractions stage during the analysis.

         Tobacco plants treated by soil drenching took up propamocarb via
    the root system. The distribution in the plant was such that the
    concentration gradient from bottom to top was of the order of 100:1,
    i.e. residue levels in the oldest leaves were 50-200 times higher than
    in the youngest leaves and flowers.

         Bluegill and channel catfish were exposed to propamocarb either
    by adding 14C-labelled compound to the water or by intraperitonal
    injection. Propamocarb was taken up from the water into the tissues,
    but in all experiments the compound disappeared when the fish were
    transferred to untreated water. Water from the experiments in which
    14C-labelled propamocarb was injected into the fish, contained
    propamocarb, metabolites which were not identified, and one compound
    which co-chromatographed with 3-dimethylaminopropylamine by TLC.

         Propamocarb is very stable to hydrolysis in acid as well as basic
    aqueous solutions. Irridiation at wavelengths above 290 nm had no
    effect on the degradation of propamocarb dissolved in water. When a
    mineral salt solution was added together with acetate, as a carbon
    source, and a few drops of lake water, propamocarb was degraded very
    rapidly after a lag phase of two weeks.

         Residues of propamocarb in plants, soil and water can be
    determined by gas chromatography using a thermionic detector operating
    in the nitrogen-specific mode. The compound is extracted with 0.1 N
    HC1, and cleaned up by partitioning between aqueous and organic
    phases. The compound is determined as propamocarb base. The limit of
    determination is 0.05-0.1 mg/kg, depending on the material analysed.
    As only very small amounts of metabolites have been observed in
    plants, soil and water, the method has been developed for
    determination of the parent compound only.

    RECOMMENDATIONS

         The following levels are recommended as temporary MRLs which need
    not to be exceeded when propamocarb is used according to good
    agricultural practice. The limits refer to the parent compound only,
    determined and expressed as propamocarb base.

                                                                

    Commodity      TMRL      Pre-harvest intervals on which
                             recommendations are based
                                                                

    Beets          0.2       drenching or seed dressing
    Cauliflower    0.2       12-40 days
    Cucumber       2         drenching or drip irrigation
    Tomato         1         drenching
    Peppers        0.2       drenching
    Strawberries   0.1       drenching or spraying after planting
                                                                


    FURTHER WORK OR INFORMATION

    Desirable

         Information on good agricultural practices, including pre-harvest
    intervals, in the use of propamocarb on fruit and vegetables.

    REFERENCES

    The Schering reports mentioned in the list are all unpublished.

    Brühl, R.           Mobility of Propamocarb Hydrochloride in Four
    June 1978a          Soils. Schering Report PA 66 752.71/6.

    Brühl, R.           Uptake of 14C-SN 66 752 by Tobacco Plants.
    September 1978b     Schering Report PA 66 752.62/6.

    Brühl, R.           Rationel Plant Uptake Study with Radioactive
    January 1979a       Propamocarb. Report of Progress I.
                        Schering Report PF-E/R+S 1/79 - PA 66 752.72/6.

    Brühl, R.           Degradation of Propamocarb Hydrochloride in a
    May 1979b           Californian Loamy Sand. Schering Report R+S 29/79
                        - PA 66 752.71/6.

    Brühl, R.           Degradation of SN 66 752 in a Loamy Sand under
    June 1979c          Anaerobic Conditions. Schering Report R+S 31/79 -
                        PA 66 572.71/6.

    Brühl, R.           Adsorption-Desorption of Propamocarb Hydrochloride
    November 1979d      in Soil and Sediment. Schering Report R+S 63/79 -
                        PA 66 752.71/6.

    Brühl, R.           Terminal Residues of Propamocarb Hydrochloride in
    February 1980       Lettuce. Report of Progress I. Schering Report R+S
                        10/80 - PA 66 752.81/6.

    Brühl, R.           Determination of Target Compounds for Residue
    May 1981a           Analysis in Propamocarb Hydrochloride Treated
                        Lettuce. Schering Report R+S 25/81 - PA 66
                        752.81/6.

    Brühl, R.           Formation of Artificial Breakdown Products During
    October 1981b       the Extraction Process of Propamocarb
                        Hydrochloride from Lettuce Tissue. Schering Report
                        R+S 38/81 - PA 66 752.81/6.

    Brühl, R. and Celorio, J.     Degradation of SN 66 752 in a Loamy
    October 1978        Sand. Schering Report PA 66 752.71/6.

    Brühl, R. and Celorio, J.     Mobility of SN 66 752 in Two Standard
    December 1979a      Soils. Schering Report R+S 68/79 - PA 66 752.71/6.

    Brühl, R. and Celorio, J.     Mobility of SN 66 752 in Two Soils After
    May 1979b           Ageing. Schering Report R+S 28/79 - PA 66
                        752.71/6.

    Brühl, R. and Celorio, J.     Degradation of Propamocarb Hydrochloride
    November 1980a      in German Standard Soils 2.2 and 2.3 at 15°C.
                        Schering Report R+S 58/80 - PA 66 752.71/6.

    Brühl, R. and Celorio, J.     Degradation of Propamocarb Hydrochloride
    December 1980b      in a Loamy Sand. Schering Report R+S 71/80 - PA 66
                        752.71/6.

    Brühl, R. and Celorio, J. Anaerobic Degradation of Propamocarb
    November 1980       Hydrochloride in River Sediment.
                        Schering Report R+S 60/80 - PA 66 752.71/6.

    Fournier, J.-C., Massenot, D. and Drogoul, C.     Effect of Various
    1981                Pesticides on the Degradation of 2,4-D,
                        Isoproturon and Propamocarb. Importance of some
                        Experimental Conditions. Proc. EWRS Symp. Theory
                        and Practice of the Use of Soil Applied
                        Herbicides, 103-110.

    Gray, C. and Knowles, C.O.    Uptake of Propamocarb Fungicide by
    1980                Bluegills and Channel Catfish. Chemosphere, 9,
                        329-333.

    Gray, C. and Knowles, C.O.    Metabolic Fate and Tissue Residues of
    1981                Propamocarb in Bluegills and Channel Catfish.
                        Chemosphere, 10, (5), 469-478.

    Hughes, L.B.        The Effects of Propamocarb Hydrochloride on
    July 1981           Symbiotic Dinitrogen Fixation, Sulfur Oxidation in
                        Soil, Carbon Turnover in Soils and Nitrogen
                        Turnover in Soil. Univ. Missouri-Columbia and
                        Schering Report.

    Iwan, J.            Metabolism of Propamocarb Hydrochloride by Soil
    July 1979           Microorganisms. Report of Progress No. 1.
                        Schering Report R+S 38/79 - PA 66 752.73/2.

    Iwan, J.            Metabolism of Propamocarb Hydrochloride by Soil
    September 1980      Microorganisms. Behaviour in Sterilized and Non-
                        Sterilized German Standard Soil 2.2 Report of
                        Progress No. 2. Schering Report R+S 48/60 - PA 66
                        752.73/2.

    Iwan, J.            Microbial Degradation of Propamocarb Hydrochloride
    February 1983       in Water. Schering Report R+S 13/83 - PA 66
                        752.73/2.

    Jenny, N.A.         Determination of SN 66752 Residues in Green and
    April 1979          Cured Tobacco (Shortened Method). Schering Report
                        66 752/NA 15.

    Jenny, N.A.         Dissipation of Propamocarb in United States Soils.
    January 1980a       Schering Report 66 752/NA 46.

    Jenny, N.A.         Dissipation of Propamocarb in United States Soils.
    February 1980b      Schering Report 66 752/NA 47.

    Klehr, M.           Photolysis of Propamocarb. HC1 (SN 66 752) in
    February 1978       Aqueous Solution. Schering Report APC 06/78.

    Klehr, M.           Photolysis Experiments with Propamocarb. HC1 (SN
    June 1980           66 752) in Heat Sterilized Aqueous Solution.
                        Schering Report.

    König, B. and Ottnad, M. Residue Determination of SN 66 752 in Water.
    July 1977a          Schering Report 66 752/1 - PA 752.51/5.

    König, B. and Ottnad, M. Specific Determination of Residues of SN
    October 1977b       66752 in Lettuce and Soil (66 752/2). Schering
                        Report PA 66 752.51/5.

    Meallier, P., Pouyet, B., Calvet, R., Fournier, J.C., Soulas, G.,
    1983                Gauvrit, C., Calmon, J.P., Mitjavila, S., Tissut,
                        M., Narbonne, J.F., Coste, C., Viallet, P. and
                        Varagnat, J. Pesticides et Environnement.
                        Groupement d'Intérét Scientifique (GIS),
                        Université Claude-Bernard Lyon I.

    Noack, S.           Determination of Residues of SN 66 752 in Green
    October 1978        and Cured Tobacco (66 752/3). Schering Report PA
                        66 752.51/8.

    Ottnad, M.          Dissipation of SN 66 752 from a Treated Soil in
    June 1977a          Frohnau (Field Study). First Report. Schering
                        Report PA 66 752.71/5.

    Ottnad, M.          Dissipation of SN 66 752 from a Treated Soil in
    July 1977b          Frohnau (Field Study). Second Report. Schering
                        Report PA 66 752.71/5.

    Ottnad, M.          Dissipation of Propamocarb Hydrochloride (SN 66
    December 1977c      752) from two German Standard Soils. First Report.
                        Schering Report PA 66 752.71/5.

    Ottnad, M.          Leaching of Propamocarb Hydrochloride in three
    January 1978a       German Standard Soils. Schering Report PA 66
                        752.71/5.

    Ottnad, M.          Dissipation of Propamocarb Hydrochloride (SN 66
    January 1978b       752) from two German Standard Soils. Second
                        Report. Schering Report PA 66 752.71/5.

    Repenthin, W.       Determination of Rates of Hydrolysis of
    June 1976           Propamocarb Base (SN 39 744) at pH 5, 7 and 9 at
                        25°C. Schering Report APC 26/76.

    Scheuermann, H.J.   Analytical Method for the Determination of
    November 1983       Residues of Propamocarb-Hydrochloride (SN 66 752)
                        by Gas Chromatography in Crops, Soil and Water (66
                        752/4). Schering Report R+S 45/83 - PA 66
                        752.51/11.


    See Also:
       Toxicological Abbreviations
       Propamocarb (Pesticide residues in food: 1984 evaluations)
       Propamocarb (Pesticide residues in food: 1986 evaluations Part II Toxicology)
       Propamocarb (JMPR Evaluations 2005 Part II Toxicological)