FAO, PL:CP/15 WHO/Food Add./67.32 EVALUATION OF SOME PESTICIDE RESIDUES IN FOOD The content of this document is the result of the deliberations of the Joint Meeting of the FAO Working Party and the WHO Expert Committee on Pesticide Residues, which met in Geneva, 14-21 November 1966.1 1 Report of a Joint Meeting of the FAO Working Party and the WHO Expert Committee on Pesticide Residues, FAO Agricultural Studies, in press; Wld Hlth Org. techn. Rep. Ser., 1967, in press ALDRIN IDENTITY Synonyms HHDN, Octalene(R) Explanation Aldrin is a technical product containing at least 95 per cent of HHDN of which the composition is as follows: 1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-endo-1,4-exo-5,8- dimethanonaphthalene; 1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-exo-1,4-endo-5,8- dimethanonaphthalene. FormulaDATA AND TOXICOLOGICAL EVALUATION Biochemical aspects When 14C-aldrin was applied to growing cultures of Aspergillus and Penicillium species, dieldrin and more hydrophilic metabolites were found in the culture medium and in the mycelium. Mosquito larvae (Aedes aegypti) cultivated in an aqueous medium to which 14C-aldrin is added, can convert this compound to hydrophilic metabolites (Ludwig et al., 1966). Following the feeding of aldrin to animals it is stored in the tissues, especially in the fat (Bann et al., 1966; Ivey et al., 1961; Lehman, 1956; Street et al., 1957; Treon & Cleveland, 1955). At low levels of intake (1 ppm) the storage ratio is large (about 60 times) but this ratio decreases rapidly to less than one with an intake of 50 ppm (Lehman, 1956). The aldrin content of the blood plasma of men occupationally exposed for 259-6044 hours over a period of eight years ranged between 0.0007 and 0.0023 ppm and was directly proportional to the duration of exposure. Aldrin added to human serum could be only partially recovered, probably because of in vitro interaction or binding with some constituent of serum such as lipoproteins. The plasma of an adult male about 18 hours after ingestion of aldrin and 10 hours after the last convulsion contained 0.036 ppm aldrin and 0.279 dieldrin. Twenty days later these concentrations were 0.0018 and 0.090 ppm respectively (Dale et al., 1966). Aldrin is largely and readily converted in the animal body, especially in the liver, to dieldrin (Bann et al., 1956; Ivey et al., 1961; Treon & Cleveland, 1955). The rate of change has not been fully established, and is independent of the site of entrance into the body. The dieldrin is stored without further change and may be recovered as such from animal products and tissues, including the eggs of fowls and the milk of dairy cows within 24 hours after ingestion (Bann et al., 1956). Fifteen minutes after an intravenous injection of 14C-aldrin, aldrin and its metabolites were found in the bile (Mörsdorf et al., 1963). In vitro epoxidation by rat liver microsomes was found to be about 10 times greater in males than in females (Wong & Terriere, 1965). Rats were fed 1 and 25 ppm of aldrin for 120 days; two metabolites were found in the urine, one of which was much more abundant in males than in females (Datta et al., 1965). Experiments with rats showed that 14C-aldrin given intravenously was converted in 24 hours mainly into hydrophilic metabolites. After 48 hours the presence of these metabolites could be demonstrated in most organs and tissues. In the urine of rabbits given 14C-aldrin intravenously, the main metabolite could be identified as one of the two enantiomorphs of 6,7-trans-dihydroxy-dihydroaldrin. The oral LD50 of this compound in mice is 1250 mg/kg bodyweight, and the intravenous LD50 is 51 mg/kg body-weight. It was found that after intravenous injection of labelled aldrin in rats, radioactive products could be demonstrated in the bile within one hour. In 4 hours, 16.2 per cent of the radioactivity was excreted in the bile. Most of the radioactivity was in the form of hydrophilic products. Perfusion tests on rat livers showed conversion of aldrin into dieldrin. From these results it was concluded that the conversion of the insecticide does in fact take place in the animal organism (Ludwig et al., 1966). Studies in rats with 14C-aldrin have shown that with daily administration of a constant dose of aldrin (4.3 µg per animal, calculated to be equivalent to 0.2 ppm in the diet) a saturation equilibrium is reached after a certain time (in male rats after about 50 days; whereas in females this saturation equilibrium is reached after as long as 200 days). After discontinuation of the daily oral administration, the compound had a biological half-life period of 10-11 days in male rats and 100 days in female rats. In faeces and urine, 70 and 95 per cent respectively of the radioactivity was in the form of hydrophilic metabolites. The conversion and excretion rate in female rats was lower at the same dose levels than in the male rats. The radioactivity found in the tissues of female animals was about double that found in male rats. Remarkable differences in the concentration of metabolites in lung, liver, spleen and kidney were found; in the female rats, the content of hydrophilic metabolites was lower and the dieldrin content higher than in the males (Ludwig et al., 1966). Acute toxicity Animal Route LD50 Reference mg/kg body-weight Mouse Oral 44 Borgmann et al., 1952 Rat, male Oral 38-54 Borgmann et al., 1952 Gaines, 1960 Lehman, 1951 Treon & Cleveland, 1955 Rat, female Oral 46-67 Borgmann et al., 1952 Gaines, 1960 Lehman, 1951 Treon & Cleveland, 1955 Rat, female Intravenous 18 Barnes, J. M., 1957 Guinea-pig Oral 33 Borgmann et al., 1952 Rabbit Oral 50-80 Borgmann et al., 1952 Treon & Cleveland, 1955 Dog Oral 65-95 Borgmann et al., 1952 Man A 25-year-old man intentionally ingested a quantity of aldrin equivalent to 25.6 mg per kg of body-weight. The following symptoms were noticed: generalized convulsions, E.E.G. changes, haematuria and albuminuria. Recovery was complete (Spiotta, 1951). Short-term studies Rat. Groups of 12 rats (6 male and 6 female) were fed diets containing 0.5, 2.5, 75 and 150 ppm aldrin for 90 days. The liver weight was increased at the two higher dosages. The mortality rate was increased at the 150 ppm level (Borgmann et al., 1952). In a feeding study lasting from 6 to 7 months, dosage levels of 5, 10 and 25 ppm aldrin were used with groups of 5 females. No enlargement of the liver or other gross change was noted. Histological data are not described. In a 9-month feeding experiment, with 20 female rats per group, the dosage levels were 5, 15, 25 and 45 ppm of aldrin. There was an increase in the liver/body-weight ratio at 45 ppm (Borgmann et al., 1952). Groups of 5 animals of each sex were given 2.5, 5, 25, 75 or 300 ppm of purified or technical aldrin in the diet for 26 weeks. Two rats of each group were killed before the end of the treatment, and the last three were killed before the thirty-seventh week. All the animals receiving 300 ppm died in 2 weeks. At 75 ppm the survival rate was good. Liver/body-weight ratio in males at 25 ppm and in both sexes at 75 and 300 ppm. Swelling of centrolobular liver cells with peripheral distribution of the cytoplasmic granules were often seen. At 2.5 and 5 ppm these changes were seen with the same frequency as in the controls. They were markedly obvious at 25 ppm and over, but regressed after the end of the treatment (Treon et al., 1951). Quail and pheasants. These animals died following concentrations of 5 ppm in the diet (Dewitt, 1955). Dog When dogs were fed, for 5 or 6 days per week, diets containing 10 to 30 ppm of aldrin, death occurred after periods of feeding ranging from a few days to about 7 months, Three groups of suckling puppies (11 days old), 3 each group comprising 2 males and 1 female were given 1.5, 3.0 and 4.5 mg/kg per day respectively, on 5 days per week. All the animals died within 38 days. A 2-month-old male and a female survived about 6 to 7 months when given 0.9 to 1.8 mg/kg body-weight per day for 6 days per week (Treon & Cleveland, 1955). When 3 groups of 3 dogs (both sexes) were given orally 0.2, 0.6 and 2.0 mg of recrystallized aldrin per kg of body-weight daily for one year, 5 of them produced litters but the pups died early, probably because of high quantities of aldrin or dieldrin in the milk of the dams. Histological liver changes were found in the dogs (Kitselman, 1953). Groups of 4 dogs (2 male and 2 female) were given 1 and 3 ppm of aldrin in their diet for 68 weeks. Liver damage occurred in 3 animals on the 3 ppm dosage level. There were significant increases in liver/body-weight ratios in the dogs on 3 ppm of aldrin. Kidney damage occurred in the female at the 1 ppm dosage level. An average concentration of aldrin of 0.3 ppm remained in the adipose tissue in the animals fed 3 ppm and 0.18 ppm remained at 1 ppm. Dieldrin occurred at a concentration of 25.4 ppm in the fat of a dog fed 1 ppm of aldrin (Treon & Cleveland, 1955; Treon et al., 1955). A group of 12 dogs was given aldrin orally for 2 years at the following daily doses - 0.2 mg/kg (2 dogs), 0.5 mg/kg (4 dogs), 1, 2 and 5 mg/kg (2 dogs each). The animals at 5 mg/kg and one of those given 2 mg/kg died within 24 days. The other animal at 2 mg/kg and the 2 given 1 mg/kg died in 1 year. All the others survived until the end of the experiment but for a dog at 0.5 mg/kg which died in a few days. Fatty changes in the liver and kidney, associated with "mild bone marrow changes" were observed at the highest doses. At 0.5 mg/kg one animal showed convulsions. No effects were seen at 0.2 mg/kg (Fitzhugh et al., 1964). Sheep and cattle. Heifers given 0.5-1 mg/kg/day for 64 days and cattle given 1.9 mg/kg/day for 10 days were not affected, whereas sheep given 6 mg/kg/day died within 28 days (Kitselman et al., 1950). Long-term studies Mouse. Groups of approximately 200 young C3HeB/Fe mice, equally divided by sex, were fed a diet containing 10 ppm of aldrin for their life-span (maximum 2 years). The aldrin shortened their average life-span by 2 months, as compared with an equal number of controls, and significantly increased the incidence of hepatic tumours (Davis & Fitzhugh, 1962). Rat. Groups of 25 female rats were fed diets containing 5, 10 and 20 ppm of recrystallized aldrin for 64 weeks. The group on 20 ppm showed an increase in weight over the controls which was correlated with an increased food intake. At the 10 ppm and 20 ppm levels the oestrus cycle was disturbed (Ball et al., 1953). In a 2-year feeding experiment, groups of 20 rats (10 male and 10 female) were given 5, 10, 50, 100 and 150 ppm of aldrin. The concentrations of 100 and 150 ppm increased the mortality rate and those of 10, 100 and 150 ppm produced microscopic changes in the liver. A single rat on 10 ppm of aldrin had specific liver changes; the rats on 5 ppm of aldrin had no noticeable liver changes. Aldrin was stored in the tissues at all dosage levels (Borgmann et al., 1952). In a second 2-year feeding experiment a group of 80 rats (40 male and 40 female) was given 2.5, 12.5 and 25 ppm of recrystallized aldrin. There was a questionable increase in mortality rate at the 25 ppm level in females. Significant increase in the liver/body-weight ratio occurred in males at all levels and at 12.5 and 25 ppm in females. Histological liver changes characteristic of organic chlorine compounds occurred at all dosage levels of aldrin (Treon & Cleveland, 1955). In a third 2-year feeding experiment, groups of 24 rats (12 male and 12 female) were given 0.5, 2, 10, 50, 100 and 150 ppm of aldrin. Concentrations of 50 ppm and above in the diet increased the mortality rate in a dose-response relationship. Liver/body-weight ratio increased at all levels of feeding. Characteristic microscopic lesions occurred in the liver at all levels; these were minimal at 0.5 ppm but increased in severity with dosage. There was an increase in tumour incidence among treated animals at all feeding levels and particularly at lower levels, but no single type of tumour predominated (Fitzhugh & Nelson, 1963). Aldrin was fed to groups of 16 female rats at 2.5, 12.5 and 25 ppm for three generations; at 12.5 and 25 ppm the number of pregnancies was reduced. The incorporation of aldrin into the diets of lactating females has a "slight to moderate" effect on mortality among the offspring at 2.5 ppm. It was severe at higher doses (Treon & Cleveland, 1955). Comments The primary site of action of aldrin is the central nervous system. CNS stimulation is the cause of death in acute poisoning. Signs of CNS stimulation are also seen after repeated high doses. Repeated doses at lower levels give rise to liver damage and, in this respect, young dogs are more susceptible than older dogs. In one long-term feeding experiment in rats there was a general increase in tumour production in the experimental animals at the lower dosage levels an compared to the controls, but the liver was not particularly affected. Liver tumours were, however, significantly increased at a dose level of 10 ppm in one strain of mice susceptible to the development of these tumours. TOXICOLOGICAL EVALUATION Levels causing no toxicological effect Dog: Questionable effects were seen at 1 ppm in the diet, equivalent to 0.025 mg/kg. Rat: Minimal changes were produced at 0.5 ppm in the diet, equivalent to 0.025 mg/kg/day. Estimate of acceptable daily intake for man 0-0.0001 mg/kg body-weight* Further work required Elucidation of the significance of the finding that aldrin is one of the compounds which affect liver cellular metabolism (p. 3). Development of methods of toxicological investigation aimed at defining and clarifying the various biological changes seen in the reported studies of this compound, with a view to removing doubts which may remain as to its safety in use. RESIDUES IN FOOD AND THEIR EVALUATION See the monograph on Dieldrin. * Sum of aldrin and dieldrin by weight. REFERENCES PERTINENT TO BIOLOGICAL DATA Ball, W. L., Kay, K. & Sinclair, J. W. (1953) Arch. industr. Hyg., 7, 292 Bann, J. M., DeCino, T. J., Earle, N. W. & Sun, Y. P. (1956) J. Agr. Food Chem. 4, 937 Barnes, J. M. (1957) Unpublished report. Borgmann, A. R., Kitselman, C. H., Dahm, P. A. & Pankaskie, J. E. (1952) Unpublished report from Kettering Laboratory, University of Cincinnati Dale, W. E., Curley, A. & Cueto, C., jr (1966) Life Sciences, 5, 47 Datta, P. R., Laug, E. P., Watts, J. O., Klein, A. K. & Nelson, M. J. (1965) Nature, 208, 289 Davis, K. J. & Fitzhugh, O. G. (1962) Toxicol. Appl. Pharmacol., 4, 187 Dewitt, J. B. (1955) J. Agr. Food Chem., 3, 672 Fitzhugh, O. G. & Nelson, A. A. (1963) Unpublished data from the United States Food and Drug Administration Fitzhugh, O. G., Nelson, A. A. & Quaife, M. L. (1964) Food Cosmet. Toxicol., 9, 551 Gaines, T. B. (1960) Toxicol. Appl. Pharmacol., 2, 88 Ivey, M. C., Claborn, H. V., Mann, H. D., Radeleff, R. D. & Woodard, G. T. (1961), J. Agr. Food Chem., 9, 374 Kitselman, C. H. (1953) J. Amer. vet. med. Ass., 123, 28 Kitselman, C. H., Dahm, P. A. & Borgmann, A. R. (1950) Amer. J. vet. Res., 41, Lehman, A. J. (1951) Quart. Bull. Assoc. Food and Drug Officials U.S., 15, 122 Lehman, A. J. (1956) Quart. Bull. Assoc. Food and Drug Officials U.S., 20, 95 Ludwig, G., Arent, H., Kochen, W., Poonawalla, N., Rechmeier, G., Stiasni, M., Vogel, J. & Korte, F. (1966) Paper presented at the Scientific Plant Protection Conference, Budapest, Hungary Mörsdorf K., Ludwig, G., Vogel, J. & Korte, F. (1963) Med. Exp., 8, 90 Spiotta, E. J. (1951) Arch. industr. Hyg., 4, 560 Street, J. C., Butcher, J. E., Raleigh, R. J. & Clanton, D. C. (1957) Proc. West. Sec. Amer. Soc. Anim. Prod., 46 (1) Treon, J. F. & Cleveland, F. P. (1955) J. Agr. Food Chem., 3, 402 Treon, J. F., Dutra, F. R., Shaffer, F. R., Cleveland, F. P., Wagner, W. & Gahegan, R. (1951) Unpublished report from Kettering Laboratory, University of Cincinnati Treon, J. F. (1955) Unpublished report from Kettering Laboratory, University of Cincinnati Wong, D. T. & Terriere, L. C. (1965) Biochem. Pharmacol., 14, 375
See Also: Toxicological Abbreviations Aldrin (ICSC) Aldrin (PIM 573) Aldrin (FAO Meeting Report PL/1965/10/1) Aldrin (FAO/PL:1967/M/11/1) Aldrin (IARC Summary & Evaluation, Supplement7, 1987) Aldrin (IARC Summary & Evaluation, Volume 5, 1974)