IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
Health and Safety Guide No. 11
TETRADIFON
HEALTH AND SAFETY GUIDE
UNITED NATIONS ENVIRONMENT PROGRAMME
INTERNATIONAL LABOUR ORGANISATION
WORLD HEALTH ORGANIZATION
WORLD HEALTH ORGANIZATION, GENEVA 1987
This is a companion volume to Environmental Health Criteria 67:
Environmental Health Criteria 67: Tetradifon
Published by the World Health Organization for the International
Programme on Chemical Safety (a collaborative programme of the United
Nations Environment Programme, the International Labour Organisation,
and the World Health Organization)
This report contains the collective views of an international group of
experts and does not necessarily represent the decisions or the stated
policy of the United Nations Environment Programme, the International
Labour Organisation, or the World Health Organization
ISBN 92 4 154367 1
ISSN 0259-7268
The World Health Organization welcomes requests for permission to
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(c) World Health Organization 1987
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that are not mentioned. Errors and omissions excepted, the names of
proprietary products are distinguished by initial capital letters.
CONTENTS
IPCS
HEALTH AND SAFETY GUIDE FOR TETRADIFON
INTRODUCTION
HOW TO USE THE GUIDE
1. PRODUCT IDENTITY AND USES
1.1. Identity
1.2. Physical and chemical properties
1.3. Composition
1.4. Uses
2. SUMMARY AND EVALUATION
2.1. Exposure to tetradifon
2.2. Effects on the environment
2.3. Uptake, metabolism, and excretion
2.4. Effects on animals
2.5. Effects on human beings
3. CONCLUSIONS AND RECOMMENDATIONS
4. HEALTH HAZARDS FOR MAN, PREVENTION AND PROTECTION, EMERGENCY
ACTION
4.1. Main hazards for man, prevention and protection, first aid
4.1.1. Prevention and protection
4.1.2. First aid
4.2. Advice to physicians
4.3. Explosion and fire hazards
4.3.1. Fire-extinguishing agents
4.4. Storage and transport
4.5. Spillage and disposal
5. INTERNATIONAL CHEMICAL SAFETY CARD
6. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
7.1. Exposure limit values
7.2. Specific restrictions
7.3. Transport and labelling
INTRODUCTION
The International Programme on Chemical Safety is responsible for the
publication of a series of Environmental Health Criteria documents,
each of which assesses the existing information on the relationship
between exposure to a specific chemical, mixture of chemicals, or
combination of chemicals and physical and biological agents, and man's
health and the integrity of the environment. The documents provide
guidelines for setting exposure limits consistent with the protection
of human health and the environment.
To facilitate the application of these guidelines in national chemical
safety programmes, "Health and Safety Guides" are being prepared,
highlighting the information contained in the documents for those who
need to know the health and environmental issues involved, but not the
scientific details. The Guides include advice on preventive and
protective measures and emergency action.
Review and revision of the information in this Health and Safety Guide
will take place in due course, and the eventual aim is to use
standardized terminology. We should be grateful if you would help by
telling us of any difficulties encountered in using the information in
this guide.
Comments please, addressed to:
The Manager
International Programme on Chemical Safety
Division of Environmental Health
World Health Organization
1211 Geneva 27
Switzerland
HOW TO USE THE GUIDE
All people in the work-place environment should be given the relevant
written information in this book, supplemented by a clear, personal
explanation to ensure that they are fully aware of the dangers and the
current courses of protective and emergency action.
The International Chemical Safety Card should be displayed as directed
and its contents clearly explained to all working personnel. Medical
staff should be fully conversant with the medical information to
ensure they can act rapidly and efficiently in an emergency. Posters
should be used to give impact to basic safety measures.
* * *
Further copies of the Health and Safety Guide and, for those requiring
more detailed scientific information, the relevant Environmental
Health Criteria publication, are available to order.
THE INFORMATION IN THIS GUIDE SHOULD BE CONSIDERED AS A STARTING POINT
TO A COMPREHENSIVE HEALTH AND SAFETY PROGRAMME
1. PRODUCT IDENTITY AND USES
1.1 Identity
Chemical formula: C12H6Cl4O2S
Chemical structure:
Common trade names: Akaritox, Aredion, Duphar 23737,
ENT 23737, FMC 5488, Mition,
NIA 5488, Polacaritox, Roztoczol,
Roztozol, Tedion V18, Tetradichlone
(a complete list of trade names is
available from IRPTC)
CAS chemical name: 1,2,4-trichloro-5-[(4-chlorophenyl)-
sulfonyl]-benzene
Synonyms: 4-chlorophenyl-2,4,5-trichlorophenyl
sulfone, 2,4,4',5-tetrachlorodiphenyl
sulfone
CAS registry number: 116-29-0
1.2 Physical and Chemical Properties
Technical tetradifon is a white crystalline solid, the solubility of
which, at room temperature in different organic solvents, varies from
10 g/litre (in kerosene and methanol) to 255 g/litre (in chloroform).
Tetradifon is resistant to hydrolysis by acid and alkali and is
non-corrosive. Particle size has a strong influence on its biological
effectiveness in that small particles show a better rain resistance
than larger ones. For details of the physical and chemical properties
of tetradifon, see the Sample International Chemical Safety Card.
1.3 Composition
Technical tetradifon is more than 94% pure. Trace amounts of
2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and highly-chlorinated
dibenzodioxins but not 2,3,7,8-TCDD have been reported as impurities
of tetradifon. However, information on specific isomers is lacking.
The contribution of these chemicals and of other compounds, such as
2,4,5-T, to the toxicity of the parent compound is not known at
present. The formulated product may be more toxic, depending on the
other compounds present in the formulation. The toxicity may also vary
with the purity of the product.
1.4 Uses
Tetradifon is used as a non-systemic acaricide, which is toxic for the
eggs and all non-adult stages of a wide range of phytophagous mites.
It is used in horticulture, including domestic greenhouses, mainly on
top-fruit, vegetables, ornamentals, hops, cotton, and sugarcane. It is
also used in forestry.
2. SUMMARY AND EVALUATION
2.1 Exposure to Tetradifon
The general population is mainly exposed to tetradifon through food,
but market-basket studies have shown that, at normal application rates
as an acaricide, residues are virtually absent from food.
2.2 Effects on the Environment
Although tetradifon is widely used as an acaricide, there are no
indications, at present, that it causes an environmental pollution
problem. Tetradifon is persistent and only slightly mobile in soils.
The compound degrades more rapidly under aerobic conditions. Both the
parent compound and its initial break-down product in the soil are
adsorbed on soil particles and resist leaching.
Tetradifon did not produce any toxic effects on cultures of Chlorella
pyrenoidova or when sprayed on the leaves of papaya plants. The
short-term toxicity of the compound is low for birds, moderate for
fish, and moderate to high for aquatic crustacea. Tetradifon is
relatively nontoxic for honey bees, and its toxicity is low for other
insects. However, it may synergize with insecticides to increase their
insecticidal potency. It does not bioaccumulate significantly in fish.
No long-term toxicity data are available and, therefore, more subtle
hazards cannot be adequately evaluated. On the basis of the data
available, tetradifon does not present a short-term threat for the
environment.
2.3 Uptake, Metabolism, and Excretion
In the rat, most orally administered tetradifon is excreted via the
bile in the faeces (70% within 48 h). Part of the remainder is
distributed in all organs and tissues. On continued dosing, tetradifon
was detected in the adipose tissue of beef cattle. It is not known
whether tetradifon is excreted in milk.
2.4 Effects on Animals
The oral LD50 for tetradifon in rats ranges from 5 000 to
14 700 mg/kg body weight. WHO (1984) categorized tetradifon as a
technical product that is unlikely to present any acute hazards, if
used as recommended. In a 90-day study on rats, 50 mg/kg diet was a
no-observed-adverse-effect level. At higher dose levels and also with
long-term administration (2 years), induction of microsomal liver
enzymes occurred, with increased liver weight. Histological changes in
the thyroid were also seen.
No effects on reproduction were found in a 2-generation study on rats
administered tetradifon in the diet. In a 90-day study on the F2b
generation, the only effects on the offspring included a reduction in
body weight gain and an increased dose-related incidence of dilated
renal pelvis.
Enlarged livers were seen in dogs at a dietary concentration of
5 000 mg/ kg. Kidney damage in the form of small infarct-like spots in
the outer cortical layer was reported at a dietary level of
5 000 mg/kg and in one of 4 dogs at 1000 mg/kg diet. The no-observed-
adverse-effect level was roughly equivalent to a daily intake of
12.5-25 mg/kg body weight.
Tetradifon was negative in short-term in vitro tests for genetic
activity. Negative results were obtained in a screening test for
carcinogenicity in mice. However, the screening test was considered to
be inadequate for the evaluation of the carcinogenicity of this
compound.
2.5 Effects on Human Beings
No adverse health effects from exposure to tetradifon have been
reported in man.
3. CONCLUSIONS AND RECOMMENDATIONS
In spite of the fact that the information available for the evaluation
of the toxic effects of tetradifon is incomplete and not always up to
present-day standards, there are no indications, at present, that its
use as an acaricide, at recommended levels, causes any health or
safety hazards for the general population, exposed workers, or the
environment.
The following recommendations were made by the Task Group:
1. More information is needed on metabolism, on the effects on
reproduction, and on long-term toxicity including
carcinogenicity.
2. The purity of the products registered and used should be
ascertained, since the contamination of the product by some
chlorinated compounds may increase its toxicity.
From: Environmental Health Criteria 67: Tetradifon
4. HEALTH HAZARDS FOR MAN, PREVENTION AND PROTECTION, EMERGENCY
ACTION
4.1 Main Hazards for Man, Prevention and Protection, First Aid
The toxicity of technical tetradifon for man is thought to be low, and
no adverse health effects from exposure to tetradifon have been
reported. The toxicity and hazard of a formulation may largely depend
on the vehicle used.
4.1.1 Prevention and protection
In spite of the low toxicity and hazard of tetradifon, the following
precautions should be observed during handling and use, in order to
reduce the risk of accidental contamination:
(a) Avoid contact with the skin and eyes. If eyes become
contaminated, flush with water. If irritation persists, obtain
medical attention.
(b) Do not smoke, drink, or eat in the work-place. Wash hands and any
exposed skin before eating, drinking, smoking, and after work.
(c) Avoid raising a dust cloud when handling wettable powder
formulations.
(d) Avoid breathing dust from powder products.
(e) When unloading and handling containers, wear protective PVC or
neoprene gloves.
(f) When handling leaking containers or when dealing with leaks and
spills, wear overalls and PVC or neoprene gloves and boots. If
overalls become contaminated, change and wash them thoroughly
before re-use.
(g) Store products in original containers out of reach of children
and away from food and feeding stuffs.
4.1.2 First aid
Poisoning by tetradifon is unlikely unless there has been gross
(negligent) exposure or intentional ingestion. In cases of
overexposure, apply routine first aid measures.
If material has been spilled on the skin, immediately remove the
patient from the source of contamination, remove all contaminated
clothing, and wash affected areas with soap and running water.
If material is in the eyes, flush with clean water for at least 15
minutes.
Keep patient prone and quiet. Start artificial respiration
immediately, if patient is not breathing.
Never give anything by mouth to an unconscious person.
In serious cases, medical attention should be sought.
4.2 Advice to Physicians
The human toxicity of tetradifon is believed to be low. There is no
specific antidote. Treat symptomatically when required. In cases of
ingestion, gastric lavage may be indicated.
4.3 Explosion and Fire Hazards
Technical tetradifon is not explosive and is not highly flammable, but
liquid formulations may be, depending on the solvent used.
4.3.1 Fire-extinguishing agents
Fight small fires with carbon dioxide, dry powder, or alcohol-
resistant Foam. Confine the use of water sprays to the cooling of
unaffected stock only, thus avoiding the accumulation of polluted run-
off from the site. Fire service personnel should be advised that self-
contained breathing apparatus may be required, because noxious fumes
may be generated through a fire.
4.4 Storage and Transport
All products should be stored in secure buildings, out of reach of
children and animals, and local transport regulations should be
complied with. Containers should be sound and well labelled.
4.5 Spillage and Disposal
Keep spectators away from any leakage. Prevent contamination of other
goods or cargo, or nearby vegetation and waterways.
Absorb spillage of liquid products with sawdust or sand, sweep up and
place in separate container.
Empty any product remaining in damaged or leaking containers into a
clean empty container, which should be suitably labelled.
Sweep up any split powder with damp sawdust taking care not to raise a
dust cloud. Place in separate container for subsequent disposal.
Contaminated absorbents, used containers, surplus product, etc.,
should be burnt in an incinerator designed for pesticide disposal.
When no incinerator is available, bury in an approved dump or in an
area where there is no risk of contamination of ground or surface
water. Comply with any local legislation applying to waste disposal.
5. INTERNATIONAL CHEMICAL SAFETY CARD
This card should be easily available to all health workers concerned
with, and users of tetradifon. It should be displayed at, or near,
entrances to areas where there is potential exposure to tetradifon,
and on processing equipment and containers. The card should be
translated into the appropriate language(s).
All persons potentially exposed to the chemical should also have the
instructions on the chemical safety card clearly explained.
TETRADIFON (technical)
(2,4,4',5-tetrachlorodiphenylsulfone; C12H6Cl4O2S)
PHYSICAL PROPERTIES OTHER CHARACTERISTICS
Relative molecular mass 356.04 Slightly yellow crystalline solid; very stable,
Melting point (°C) 148-149 non-corrosive substance; may emit toxic fumes
Water solubility (20°C) 0.08 mg/litre when heated to decomposition
Density (20°C) 1.515
Octanol/water partition coefficient 4.61
Vapour pressure (20°C) 0.32 x 10-10kPa
HAZARDS/SYMPTOMS PREVENTION AND FIRST AID
PROTECTION
SKIN: Mild irritation Wear neoprene gloves, Remove contaminated clothing; wash with plenty
face shield of water
EYES: Marginal irritant Wear safety goggles, face shield Flush with clean water for a least 15 minutes
INHALATION: Irritation of upper Local exhaust ventilation; Fresh air
respiratory tract wear a dust mask
INGESTION: Not observed Unlikely professional hazard Gastric lavage may be indicated
SPILLAGE STORAGE FIRE AND EXPLOSION
Collect spillage in closed container Cool and dry storage in original Not flammable or explosive under normal conditions;
or dust bin bag; in the case of liquid, packaging fire extinguishing agents include foam, CO2,
first use absorbant material: clean up and dry chemical
with water
(cont'd)
WASTE DISPOSAL
Should be burnt in an incinerator National Occupational Exposure
designed for pesticide disposal Limit:
National Poison Control Centre:
6. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
No effects on the environment have been reported for tetradifon.
However, contamination of ponds, waterways, and ditches with the
product or used containers should be avoided. Empty containers should
be punctured to prevent re-use.
7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
The information given in this section has been extracted from the
International Register of Potentially Toxic Chemicals (IRPTC) legal
file.
The reader should be aware that regulatory decisions about chemicals
taken in a certain country can only be fully understood in the
framework of the legislation of that country. A full reference to the
original national document from which the information was extracted
can be obtained from the IRPTC.a
When no effective date appears in the IRPTC legal file, the
publication year of the national document from which the data are
taken is mentioned; where appropriate, this is indicated by (r).
7.1 Exposure Limit Values
Some exposure limit values are given in the following table.
7.2 Specific Restrictions
In Czechoslovakia (effective date: 1981) and the United Kingdom
(1983 (r)), the substance is approved as a pesticide or acaricide, and
specified uses, limitations, and safety precautions are listed. In the
USSR, the substance is approved as an insecticide for agricultural use
and application; dose, mode, and treatment frequency are specified
(effective date: 1982).
In Sweden, the substance is an active ingredient in pesticide
formulations that are registered at the products control board and
therefore may be marketed and used. The formulations may be sold only
to persons authorized to use such formulations (1984 (r)).
a International Register of Potentially Toxic Chemicals, Palais des
Nations, 1211 Geneva 10, Switzerland (Telephone No. 988400 - 985850).
7.3 Transport and Labelling
The United Nations Committee of Experts on the Transport of Dangerous
Goods classifies tetradifon as a poisonous substance (Class 6.1)
presenting minor danger for packing purposes when the active
ingredient constitutes 25 - 100% of the formulation (1982 (r)).
The recommended label is:
SOME EXPOSURE LIMIT VALUES
MEDIUM SPECIFICATION COUNTRY EXPOSURE LIMIT DESCRIPTION VALUE EFFECTIVE
(mg/kg) DATE
FOOD Plant Argentina Maximum limit 1-5 1969
Meat, milk 0 1969
Mint 100 1969
Hops 30 1969
Dried hops 120 1969
FOOD Plant products Brazil Acceptable limit 1-5 1984 (r)
(specified) (security interval: 2-14 days)
FOOD Plant (specified) Germany, Federal Republic of Maximum residue limit 1.5 1984
Plant products Maximum residue limit 0.05 1984
(specified)
FOOD Food products Kenya Maximum limit 1-100 1978 (r)
(specified)
FOOD Fruits, vegetables Sweden Maximum acceptable concentration 2 1985
FOOD Food products USA Residue tolerance 8-120 1981 (r)
(specified)
Raw agricultural Acceptable residue limit 0-100 1981 (r)
products (specified)
FOOD Food products USSR Maximum residue limit 0.1-0.7 1983
(specified)