IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
Health and Safety Guide No. 23
QUINTOZENE
HEALTH AND SAFETY GUIDE
UNITED NATIONS ENVIRONMENT PROGRAMME
INTERNATIONAL LABOUR ORGANISATION
WORLD HEALTH ORGANIZATION
WORLD HEALTH ORGANIZATION, GENEVA
This is a companion volume to Environmental Health Criteria 41:
Quintozene
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)
ISBN 92 4 154335 3
ISSN 0259 - 7268
(c) World Health Organization 1989
Publications of the World Health Organization enjoy copyright
protection in accordance with the provisions of Protocol 2 of the
Universal Copyright Convention. For rights of reproduction or
translation of WHO publications, in part or in toto, application
should be made to the Office of Publications, World Health
Organization, Geneva, Switzerland. The World Health Organization
welcomes such applications.
The designations employed and the presentation of the material in this
publication do not imply the expression of any opinion whatsoever on
the part of the Secretariat of the World Health Organization
concerning the legal status of any country, territory, city or area or
of its authorities, or concerning the delimitation of its frontiers or
boundaries.
The mention of specific companies or of certain manufacturers'
products does not imply that they are endorsed or recommended by the
World Health Organization in preference to others of a similar nature
that are not mentioned. Errors and omissions excepted, the names of
proprietary products are distinguished by initial capital letters.
CONTENTS
INTRODUCTION
1. PRODUCT IDENTITY AND USES
1.1. Identity
1.2. Physical and chemical properties
1.3. Analytical methods
1.4. Production and uses
2. SUMMARY AND EVALUATION
2.1. Quintozene toxicity
2.2. Human exposure to quintozene
2.3. Evaluation of health risks for man
2.4. Evaluation of effects on the environment
3. CONCLUSIONS AND RECOMMENDATIONS
3.1. Conclusions
3.2. Recommendations
4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
4.1. Main human health hazards, prevention and protection,
first aid
4.1.1. Advice to physicians
4.1.2. Health surveillance advice
4.2. Explosion and fire hazards
4.2.1. Explosion hazards
4.2.2. Fire hazards
4.3. Storage
4.3.1. Leaking containers in store
4.4. Transport
4.5. Spillage and disposal
4.5.1. Spillage
4.5.1.1 Solid products
4.5.1.2 Liquid products
4.5.1.3 All products
4.5.2. Disposal
5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
6. INTERNATIONAL CHEMICAL SAFETY CARD
7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
7.1. Previous evaluations by international bodies
7.2. Exposure limit values
7.3. Specific restrictions
7.4. Labelling, packaging, and transport
7.5. Waste disposal
BIBLIOGRAPHY
INTRODUCTION
The Environmental Health Criteria (EHC) documents produced by the
International Programme on Chemical Safety include an assessment of
the effects on the environment and on human health of exposure to a
chemical or combination of chemicals, or physical or biological
agents. They also provide guidelines for setting exposure limits.
The purpose of a Health and Safety Guide is to facilitate the
application of these guidelines in national chemical safety
programmes. The first three sections of a Health and Safety Guide
highlight the relevant technical information in the corresponding EHC.
Section 4 includes advice on preventive and protective measures and
emergency action; health workers should be thoroughly familiar with
the medical information to ensure that they can act efficiently in an
emergency. Within the Guide is an International Chemical Safety Card
which should be readily available, and should be clearly explained, to
all who could come into contact with the chemical. The section on
regulatory information has been extracted from the legal file of the
International Register of Potentially Toxic Chemicals (IRPTC) and from
other United Nations sources.
The target readership includes occupational health services, those in
ministries, governmental agencies, industry, and trade unions who are
involved in the safe use of chemicals and the avoidance of
environmental health hazards, and those wanting more information on
this topic. An attempt has been made to use only terms that will be
familiar to the intended user. However, sections 1 and 2 inevitably
contain some technical terms. A bibliography has been included for
readers who require further background information.
Revision of the information in this Guide will take place in due
course, and the eventual aim is to use standardized terminology.
Comments on any difficulties encountered in using the Guide would be
very helpful and should be addressed to:
The Manager
International Programme on Chemical Safety
Division of Environmental Health
World Health Organization
1211 Geneva 27
Switzerland
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
Common name: Quintozene
Chemical formula: C6Cl5NO2
Chemical structure:
Common trade names: Avicol, Botrilex, Brassicol, Earthcide,
Fartox, Folosan, Fomac 2, Fungiclor, GC
3944-3-4, Kobu, Kobutol, KP 2,
NCI-C00419, Olpisan, PCNB, Pentagen,
Terraclor, Terrafum, Tilcarex, Tritisan
(a complete list of trade names is
available from IRPTC (1983)
CAS chemical name: pentachloronitrobenzene
CAS registry number: 82-68-8
Relative molecular mass: 295.36
Hexachlorobenzene is often found as a contaminant in quintozene and
levels can range up to 3% (in the past, levels as high as 30% were
found, but regulations have been introduced in many countries to
restrict these levels).
1.2 Physical and Chemical Properties
Quintozene is a pale yellow-to-white (depending on the purity) solid
with a musty odour and a melting point of 142-146°C. It is soluble in
carbon disulfide, benzene, chloroform, ketones, and aromatic and
chlorinated hydrocarbons, but is practically insoluble in water.
It is quite stable in soil, but eventually degrades to
pentachloroaniline (PCA).
1.3 Analytical Methods
Gas chromatography combined with electron capture detection is used
for the analytical determination of quintozene.
1.4 Production and Uses
Quintozene has been used as a soil fungicide and as a seed dressing
since the 1930s. It is available as a wettable powder, dust,
emulsifiable concentrate, granules, or in combination products.
2. SUMMARY AND EVALUATION
2.1 Quintozene Toxicity
On the basis of the oral LD50 in the rat of 12 000 mg/kg, WHO (1986)
classified quintozene in the category of technical products unlikely
to present an acute hazard in normal use.
No-observed-adverse-effect levels in long-term studies on the rat and
the dog were 1.25 and 0.75 mg/kg body weight (25 and 30 mg/kg diet),
respectively. In long-term studies on rats and at higher dosages
(63 mg/kg diet), quintozene gave rise to liver hypertrophy with some
histopathological changes; dogs administered 5000 mg quintozene/kg
diet exhibited more severe liver damage with fibrosis. In short-term
studies on female rats, quintozene caused induction of mixed-function
oxidases.
Quintozene is partly metabolized and partly excreted unchanged and
does not accumulate in tissues.
Purified quintozene is not considered to be teratogenic.
Quintozene is generally negative in short-term tests for genetic
activity.
Equivocal or negative findings have been reported in carcinogenicity
studies on rats and mice.a Hexachlorobenzene, an impurity in
technical quintozene, is carcinogenic for mice, rats, and hamsters.
Quintozene is a weak skin sensitizer, but not an irritant.
With the exception of a single case of conjunctivitis in an
occupational setting, no other cases of poisoning or adverse effects
have been reported in man.
2.2 Human Exposure to Quintozene
The general population can be exposed through residues in food,
especially in oils and fats. Information on exposure from other
sources is lacking. No cases of accidental or occupational
overexposure have been reported.
a In a recent (1986) NTP study on purified PCNB in mice, no
evidence of carcinogenicity was found at high dose levels.
2.3 Evaluation of Health Risks for Man
With the exception of some data on residues in food, no human exposure
data are available for quintozene. It is therefore difficult to
evaluate the hazard for man of present exposures to this substance.
Nevertheless, the low toxicity of quintozene that has been
demonstrated in short-term and long-term animal studies indicates a
low degree of concern in relation to human health effects.
2.4 Evaluation of Effects on the Environment
Quintozene persists in soil with a half-life within the range of 4-10
months. Part of it is lost from the soil by volatilization.
Biodegradation, mainly to pentachloroaniline, is an important route of
conversion. Photodegradation is not important.
The only significant adverse effect reported for quintozene is on
earthworms. In laboratory tests, quintozene applied as a soil
fungicide, at recommended doses, appeared to have long-term toxic
effects on the earthworm. Unfortunately, no observations of the
effects on earthworms of quintozene alone, during field use, are
available.
There is no evidence that quintozene represents a threat to non-target
organisms. It has a very low acute toxicity for fish and Daphnia.
Its bioaccumulation by fish is low, and no effects have been reported
on terrestrial plants, birds, or microorganisms.
3. CONCLUSIONS AND RECOMMENDATIONS
3.1 Conclusions
(a) The general population does not appear to be at risk from
residues of quintozene in food.
(b) Exposure of the general population via air and drinking-water
could not be evaluated because of lack of data.
(c) Occupational exposure has not been reported to cause any adverse
effects.
(d) There is limited information on the effects of quintozene in the
general environment. It has been shown to be toxic for
earthworms in laboratory tests. Data on other organisms suggest
that quintozene does not pose a problem in the general
environment.
(e) Quintozene does not biomagnify.
(f) The major toxicological concern with quintozene is the presence
of hexachlorobenzene as an impurity.
3.2 Recommendations
Levels of impurities in quintozene, especially hexachlorobenzene,
should be kept to a minimum.
4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
4.1 Main Human Health Hazards, Prevention and Protection, First Aid
Quintozene is a practically non-toxic organochlorine fungicide.
Nevertheless, the correct precautions should be observed in its
handling and use.
For details see the International Chemical Safety Card on pages 18-21.
4.1.1 Advice to physicians
Poisoning is unlikely to occur unless a massive overdose is swallowed.
In this case, it is not necessary to induce vomiting. If gastric
lavage is undertaken, a cuffed endotracheal tube should be used.
Otherwise, a clear airway should be maintained and respiration should
be safeguarded.
4.1.2 Health surveillance advice
No routine medical supervision is required.
4.2 Explosion and Fire Hazards
4.2.1 Explosion hazards
The explosion hazard will depend on the solvent used in the
formulation or on the characteristics of the dust.
4.2.2 Fire hazards
Liquid formulations containing organic solvents may be flammable.
Extinguish fires with alcohol-resistant foam, carbon dioxide, or
powder. With sufficient burning or external heat, quintozene will
decompose, emitting toxic fumes. Fire-fighters should be equipped
with self-contained breathing apparatus, eye protection, and full
protective clothing.
The use of water spray should be confined to the cooling of unaffected
stock, thus avoiding the accumulation of polluted run-off from the
site.
4.3 Storage
Products should be stored in locked buildings, preferably dedicated to
pesticides, and kept out of reach of children and unauthorized
personnel. They should not be stored near foodstuffs or animal feed.
4.3.1 Leaking containers in store
Take precautions and use appropriate personal protection (see the
International Chemical Safety Card on pages 18-21). Empty any product
remaining in the damaged/leaking containers into a clean empty drum,
which should then be tightly closed and suitably labelled.
Sweep up spillage with sawdust, sand, or earth (moisten for powders),
and dispose of safely (section 4.5.2).
After emptying, leaking containers should be rinsed with at least
1 litre of water per 20-litre drum. Swirl round to rinse the walls,
empty, and add the rinsings to the sawdust or earth. Puncture the
container to prevent re-use.
4.4 Transport
Local requirements regarding movements of hazardous goods should be
complied with. The product should not be transported in the same
compartment as foodstuffs. Containers should be checked before
despatch to ensure that they are sound and that the labels are
undamaged.
4.5 Spillage and Disposal
4.5.1 Spillage
Before dealing with any spillage, the necessary precautions should be
taken and appropriate personal protection should be used (see the
International Chemical Safety Card on pages 18-21).
4.5.1.1 Solid products
The remaining spilled product should be absorbed on moist sawdust,
sand, or earth, swept up, and transferred in a suitable container to a
safe place for disposal (section 4.5.2).
4.5.1.2 Liquid products
The liquid can be prevented from spreading or contaminating other
cargo, vegetation, or waterways, by making a barrier of the most
suitable material available, e.g., earth or sand.
Spilled liquid should be absorbed on sawdust, sand, or earth, swept up
and placed in a closeable container for later transfer to a safe place
for disposal (section 4.5.2).
4.5.1.3 All products
As soon as possible after the spillage and before re-use, all
contaminated areas should be covered with damp sawdust, sand, or
earth. This should be swept up and placed in a closeable container
for later transfer to a safe place for disposal. Care should be taken
to avoid run-off into water courses.
4.5.2 Disposal
Surplus product, contaminated absorbents, and containers should be
disposed of in an appropriate way. Waste material should be burned in
a proper incinerator designed for organochlorine waste disposal
(1000°C and 30 min residence time with effluent gas scrubbing). If
this is not possible, it should be buried in an approved dump or
landfill where there is no risk of contamination of surface or ground
water. Local legislation regarding disposal of toxic wastes should be
complied with. Containers must be punctured to prevent re-use.
5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION
Although there is limited information on the effects of quintozene in
the general environment, it has been shown to be toxic for earthworms.
Data on other organisms suggest that quintozene is not a problem in
the general environment. Its bioaccumulation by fish is low. It does
not biomagnify.
Discharges arising from the manufacture, formulation, and use of
quintozene should not be allowed to pollute the environment and should
be treated properly.
6. INTERNATIONAL CHEMICAL SAFETY CARD
This card should be easily available to all health workers concerned
with, and users of, quintozene. It should be displayed at, or near,
entrances to areas where there is potential exposure to quintozene,
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.
Space is available on the card for insertion of the National
Occupational Exposure Limit, the address and telephone number of the
National Poison Control Centre, and for local trade names.
QUINTOZENE
C6Cl5NO2
CAS chemical name: pentachloronitrobenzene
CAS registry number: 82-68-8
PHYSICAL PROPERTIES OTHER CHARACTERISTICS
Melting point (°C) 142 - 146 Pale yellow-to-white solid with a musty odour; technical
Density (25°C) 1.718 grade may contain hexachlorobenzene as a contaminant;
Vapour pressure (kPa at 20°C) 10-8 x 667 it is rather stable in soil; it is used as a fungicide
Relative molecular mass 295.36 in agriculture, horticulture, and in soil and seed
Solubility in: treatment
water (20°C) 0.44 mg/litre
(practically insoluble)
ethanol (25°C) 2%
most other organic solvents soluble
HAZARDS/SYMPTOMS PREVENTION AND PROTECTION FIRST AID
SKIN: Repeated contamination may Avoid skin contact, wear Remove contaminated clothing; wash
cause sensitization clean overalls and protective skin with water and soap
gloves; launder contaminated
clothing before re-use
EYES: May cause irritation, Avoid working in a dusty Flush with clean water for 15 minutes;
redness atmosphere if irritation persists, seek medical
attention
INHALATION: Dust may irritate Avoid working in a dusty atmosphere
INGESTION: Unlikely occupational Do not eat, drink, or smoke
hazard during work; wash hands before
eating, drinking, or smoking
Massive accidental or intentional Obtain medical attention; do not induce
ingestion may cause poisoning vomiting
REPEATED EXPOSURE - SKIN, Same as above; take shower In case of poisoning, same as above
INHALATION, INGESTION: and put on clean clothing after
unlikely to cause adverse effects, work
unless massive exposure; may,
however, cause skin sensitization
ENVIRONMENT: Toxic for Do not pollute the environment with
earthworms waste material or discharges
SPILLAGE STORAGE FIRE AND EXPLOSION
Take appropriate personal Products should be stored in Liquid formulations containing organic
precautions; prevent liquid locked buildings preferably solvents may be flammable; emulsifiable
from spreading or contaminating dedicated to insecticides; keep concentrates are miscible with water;
other cargo, vegetation, or products out of reach of children extinguish fires with alcohol-resistant
waterways, with a barrier of the and unauthorized personnel; do foam, CO2, or powder; with sufficient
most suitable material available, not store near foodstuffs or animal burning or external heat, quintozene will
e.g., earth or sand feed decompose, emitting toxic fumes; the
smoke and fumes could be injurious
Absorb spilled liquid with through inhalation, or absorption through
sawdust, sand, or earth; sweep up the skin; therefore, protective clothing and
and place it in a closeable container self-contained breathing apparatus should
for later safe disposal be worn; the use of water spray should
be confined to the cooling of unaffected
stock, thus avoiding the accumulation of
polluted run-off from the site
WASTE DISPOSAL NATIONAL INFORMATION
Waste material should be burned in National Occupational Exposure
a proper incinerator designed for Limit:
organochlorine waste disposal;
if this is not possible, bury in
an approved dump or landfill where National Poison Control Centre:
there is no risk of contamination
of surface or ground water; comply
with any local legislation Local Trade Names:
regarding disposal of toxic wastes
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 and other UN sources. The intention is to give the reader a
representative, but non-exhaustive, overview of current regulations,
guidelines, and standards.
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
7.1 Previous Evaluations by International Bodies
The FAO/WHO Joint Meeting on Pesticide Residues (JMPR) reviewed
residue and toxicity data on quintozene in 1969, 1973, 1974, 1975, and
1977. The conclusion in 1977 was that 25 mg/kg diet, equivalent to
1.25 mg/kg body weight was a no-observed-adverse-effect-level in the
rat and 30 mg/kg diet, equivalent to 0.75 mg/kg body weight, in
the dog. On the basis of these data, the estimate of an
acceptable daily intake (ADI) for man was 0-0.007 mg/kg body weight.
IARC (1974) did not come to a conclusion on the carcinogenicity of
quintozene, because of lack of data at the time. FAO/WHO (1978)
concluded that there were no indications that administration of
quintozene resulted in carcinogenic activity.
In the WHO recommended classification of pesticides by hazard and
guidelines to classification (WHO, 1986), quintozene is classified in
the category of technical products unlikely to present an acute hazard
in normal use.
7.2 Exposure Limit Values
Some exposure limit values are given in the table on pages 23-25.
When no effective date appears in the IRPTC legal file, the year of
the reference from which the data were taken is indicated by (r)
a The regulations and guidelines of all countries are subject to
change and should always be verified with the appropriate
regulatory authorities before application.
EXPOSURE LIMIT VALUES
Medium Specification Country/ Exposure limit description Value Effective
organization date
AIR Work-place Bulgaria Maximum permissible concentration (MPC) 0.5 mg/m3
USSR Maximum allowable concentration (MAC) 1977
- Ceiling value for vapour, aerosol 0.5 mg/m3
AIR Ambient USSR Maximum allowable concentration (MAC)
- 1 × /day 0.01 mg/m3
- Average per day 0.006 mg/m3
FOOD Intake from FAO/WHO Acceptable daily intake (ADI) 0.007 mg/kg 1977
body weight
USSR Acceptable daily intake (ADI) 0.007 mg/kg 1983
FOOD Plant Brazil Acceptable limit 0.01-5 mg/kg
Czechoslovakia Maximum residue limit (MRL) 0.01-0.1 mg/kg 1978
FAO/WHO Maximum residue level 0.01-5 mg/kg
Finland Maximum residue limit 0.2-0.3 mg/kg 1987
Germany, Maximum residue limit (MRL) 0.01-0.3 mg/kg 1984
Federal
Republic of
Kenya Maximum limit 0.02-10 mg/kg
Netherlands Maximum residue limit (MRL) 1987
- Certain foodstuffs 0.02-3 mg/kg
Medium Specification Country/ Exposure limit description Value Effective
organization date
Sweden Maximum tolerable concentration 0.2-1 mg/kg
USA Acceptable residue limit 0.1-1 mg/kg
(interim tolerance limit)
FOOD Animal Germany, Maximum residue limit (MRL) 0.01-0.2 mg/kg 1984
Federal
Republic of
Sweden Maximum tolerable concentration 0.005-0.1 mg/kg 1983
FEED Argentina Maximum limit 0 mg/kg 1969
USSR Prohibition 0 mg/kg 1981
GOODS Argentina Maximum limit 1971
- Tobacco 0 mg/kg
Germany, Maximum residue limit (MRL) 0.2 mg/kg 1984
Federal
Republic of
7.3 Specific Restrictions
The use of quintozene is permitted with certain restrictions in, among
other countries, the Federal Republic of Germany, Finland, Japan, the
Netherlands, the United Kingdom, the USA, and the USSR. In the USA,
the hexachlorobenzene level must be reduced to less than 0.1% in
technical products. In the Netherlands, the technical material used
in the formulation may not contain more than 1 g hexachlorobenzene and
10 g pentachlorobenzene per kg. The use of quintozene was prohibited
in Italy in 1973.
7.4 Labelling, Packaging, and Transport
No specific guidelines found.
7.5 Waste Disposal
In the USA, any non-domestic waste containing quintozene must be
treated as hazardous waste. Specific instructions are given for
incineration. Under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) of 1980, as amended, unless
in compliance with a specified permit or procedure, owners/operators
of vessels or onshore or offshore facilities must notify the USA
government of any release of pentachloronitrobenzene (quintozene), in
or on navigable waters, adjoining shorelines, the contiguous zone, or
beyond the contiguous zone, or to any other environmental media (air,
land, or ground water) in an amount equal to or greater than one pound
(0.454 kilogram). The United States Environmental Protection Agency,
on March 16 1987, proposed raising this reportable quantity to
100 pounds (45.4 kilograms), but has not yet done so.
In Finland, any waste containing quintozene is classified as hazardous
waste and must be treated according to specific instructions.
BIBLIOGRAPHY
FAO (1985a) Guidelines for the packaging and storage of pesticides.
Rome, Food and Agriculture Organization of the United Nations.
FAO (1985b) Guidelines for the disposal of waste pesticides and
pesticide containers on the farm. Rome, Food and Agriculture
Organization of the United Nations.
FAO (1985c) Guidelines on good labelling practice for pesticides.
Rome, Food and Agriculture Organization of the United Nations.
GIFAP (1982) Guidelines for the safe handling of pesticides during
their formulation, packing, storage and transport. Brussels,
Groupement International des Associations Nationales des Fabricants de
Produits Agrochimiques.
GIFAP (1983) Guidelines for the safe and effective use of
pesticides. Brussels, Groupement International des Associations
Nationales des Fabricants de Produits Agrochimiques.
GIFAP (1984) Guidelines for emergency measures in cases of pesticide
poisoning. Brussels, Groupement International des Associations
Nationales des Fabricants de Produits Agrochimiques.
GIFAP (1987) Guidelines for safe transport of pesticides.
Brussels, Groupement International des Associations Nationales des
Fabricants de Produits Agrochimiques.
IARC (1972-present) IARC monographs on the evaluation of
carcinogenic risk of chemicals to man. Lyons, International Agency
for Research on Cancer.
IRPTC (1983) IRPTC legal file 1983. Geneva, International Register
of Potentially Toxic Chemicals, United Nations Environment Programme.
IRPTC (1985) IRPTC file on treatment and disposal methods for waste
chemicals. Geneva, International Register of Potentially Toxic
Chemicals, United Nations Environment Programme.
PLESTINA, R. (1984) Prevention, diagnosis, and treatment of
insecticide poisoning. Geneva, World Health Organization
(Unpublished WHO document VBC/84.889).
SAX, N.I. (1984) Dangerous properties of industrial materials. New
York, Van Nostrand Reinhold Company, Inc.
UNITED NATIONS (1986) Recommendations on the transport of dangerous
goods. 4th ed. New York, United Nations.
US NIOSH/OSHA (1981) Occupational health guidelines for chemical
hazards, 3 Vol. Washington DC, US Department of Health and Human
Services, US Department of Labor (Publication No. DHHS(NIOSH) 01-123).
WHO (1984) EHC No. 41: Quintozene. Geneva, World Health
Organization, 38 pp.
WHO (1986) The WHO recommended classification of pesticides by
hazard and guidelines to classification 1986-87. Geneva, World
Health Organization (Unpublished document VBC/86.1).
WHO/FAO (1975-87) Data sheets on pesticides. Geneva, World Health
Organization (Unpublished documents).
WORTHING, C.R. & WALKER, S.B. (1983) The pesticide manual. 7th
ed. Lavenham, Lavenham Press Limited, British Crop Protection Council.