Parathion

Protective measures that have been applied concerning the chemical
Annex 1 - further information on the substance
Annex 2 - details on reported control actions
Annex 3 - list of designated national authorities
Annex 4 - References

Published: June 97

Common Name	Parathion
Other names/ Synonyms	Ethyl parathion, parathion ethyl
CAS-No.	56-38-2
Use	Agricultural chemical, insecticide
Trade Names	Alkron, Aileron, Aphamite, Bladan, Corothion, Etilon, Folidol, E-605, Fostox E, Geofos,
	Kriss, Niram, Orthophos, Panthion, Paramar, Paraphos, Parathene, Parawet,
	Penncap-E, Phoskil, Rhodiatox, SNP, Soprathion, Stathion, thiophos, Vitrex
Formulation Types	Aerosols, capsule suspension (CS), dustable powder (DP), emulsifiable concentrate(EC), granules (GR) and wettable powders (WP). Formulations range from a 1% dust to an 83.5 concentrate. The technical grade material is 98 % pure.
Basic Manufacturers	Cheminova (Denmark)

Reasons for Inclusion In the PIC Procedure

All formulations of this substance (except capsule suspensions) are included because of their acute hazard classification and concern as to their impact on human health under conditions of use in developing countries.

The 3^rd Joint Expert Group Meeting decided to include all formulations of parathion in the PIC procedure except capsule suspensions (CS). The principal reason for actions regarding parathion and its inclusion in the PIC procedure relate to its high acute toxicity. The active ingredient and its most typical formulations fall into the WHO classification by hazard 1a or 1b. The draft WHO health and safety guide noted "there are more reported cases of poisoning with parathion than with any other pesticide currently in use". (IPCS, 1991)

Registrars need to carefully consider the formulations actually used in each country when determining the risks of continued use of this pesticide. The toxicity of the active ingredient is high, but some formulations may fall into a much lower category of hazard.

Hazard Classification by International Organisms
WHO (WHO, 1996)	Technical product.: la (extremely hazardous), classification based on oral toxicity
	Classification of formulations
		oral toxicity		dermal toxicity
		LD50: 2 mg/kg bw (see Ann. 1)		LD50: 50 mg/kg bw (see Ann. 1)
	formulation	a.i.(%)	hazard class	a.i. (%)	hazard class
	liquid	>20	la	>15	Ib
		>1	Ib	>1	II
	solid	>50	la	>45	Ib
		>5	Ib	>3	II
EPA	Category 1 (highly toxic) Group C (possible human carcinogen)
EU	T+ (very Toxic)
IARC	Group 3; not classifiable as to their carcinogenicity to humans

Protective measures that have been applied concerning the chemical

Measures to Reduce Exposures

Personal	WHO recommends that for the health and welfare of workers and the general population, the handling and application of parathion should be entrusted only to competently supervised and well-trained applicators, who must follow adequate safety measures and use the chemical according to good application practices. Regularly exposed workers should receive appropriate monitoring and health evaluation. (IPCS, 1991)
	Use in the USA of formulations containing parathion as a pesticide must be carried out by or under the direct supervision of a certified applicator, and no worker is allowed to enter a field treated with parathion less than 48 hours after the treatment. (US-EPA, 1991; FAO, 1995; IPCS, 1991; IARC, 1979; US-EPA, 1986; US-EPA, 1992; US-EPA, 1991)
Protection	Protective clothing as indicated in the FAO Guidelines for Personal Protection when Working with Pesticides in Tropical Climates (FAO, 1990) is required; a respirator should also be worn by mixers and when spraying tall crops. The use of flaggers should be avoided; if used, they need full protective clothing including a respirator. All equipment and protective clothing should be washed thoroughly after use; clothing should be laundered separately from family clothing.
	Unprotected workers should be kept out of treated areas for 48 hours. (FAO, 1990)
Application	The manufacture, formulation, agricultural use and disposal of parathion should be carefully managed to minimize contamination of the environment. To minimize risks for all individuals, a 48-hour interval between spraying and re-entry into any sprayed area is recommended.
	Pre-harvest intervals have been set in many countries. These are generally in the range of 7-15 days, but for greenhouse use they may be twice as long and, for certain fruits, may last up to 5 weeks.
	In view of the high toxicity of parathion, this agent should not be considered in hand-applied ULV spraying practices. (IPCS, 1991)
	In 1991 the use of Parathion was restricted by US-EPA. In order to reduce exposure, remaining uses are restricted: i) for aerial application by commercial applicators when wind speeds do not exceed 10 mph; ii) closed-system transfer must be used; iii) a 100-foot buffer zone must be maintained around water, roads and public buildings; iv) all treated crops must be harvested mechanically; v) early re-entry into fields is permitted only for scouting and irrigation and is limited to one hour in any 24-hour period; and vi) any exposure incidents involving workers, spray drift or wildlife deaths must be reported. Unprotected field workers should be kept out of treated areas for at least 1-2 days. (US-EPA; 1991,1992)

Regulatory measures

Although the chemical has been included in the PIC procedure because it is a highly toxic pesticide that is likely to cause problems under conditions of storage, transportation and use in developing countries, some countries have reported control actions that may be of interest when considering its use as a pesticide (see below).

Actions to ban or severely restrict parathion have been reported by several countries. (Annex 2). Twelve countries have imposed a total ban on the use of parathion; in the USA, use is restricted to some applications and in New Zealand the substance was voluntarily withdrawn by the registrant.

Not all of the reports have been determined to be of control actions which conform with the FAO/UNEP definition of banned or severely restricted for health or environmental reasons. However, all reports are provided here since the FAO/UNEP Joint Expert Group on Prior Informed Consent decided that the substance should be included in the PIC procedure due to its potential to cause problems under conditions of use in developing countries regardless of the number of qualifying actions.

For further information on the control actions provided in Annex 2, contact the Designated National Authorities (Annex 3) in the country reporting the control action.

Alternatives

Alternatives were reported by three countries. India indicated fenitrothion and methyl parathion. The latter substances was also cited by Thailand. Sri Lanka reported the use of IPM strategies in rice to substitute the pesticide. Alternatives have been reported in literature. (Gips, 1990)

It is essential that before a country considers substituting any of the reported alternatives, it ensures that the use is relevant to their national needs. A first step may be to contact the DNA in the country where the alternative has been reported (see addresses of DNAs in Annex 3). It will then be necessary to determine the compatibility with national crop protection practices,

Packaging and Labelling

Follow FAO Revised Guidelines on Good Labelling Practice for Pesticides (FAO, 1995).

The United Nations Committee of Experts on the Transportation of Dangerous Goods classifies the chemical in:

Hazard Class 6.1	poisonous substance
Packing Group 1:	substances and preparations presenting a very severe risk of poisoning (formulations containing 40-100 % active ingredient)
Packing Group 2:	substances and preparations presenting a serious risk of poisoning (formulations containing 4-40 % active ingredient)
Packing Group 3:	harmful substances and preparations presenting a relatively low risk of poisoning (solid formulations containing 1-4% active ingredient and liquid formulations containing 0.4-4 % active ingredient)

Waste Disposal

See FAO Guidelines on Prevention of Accumulation of Obsolete Pesticide Stocks and The Pesticide Storage and Stock Control Manual. (FAO, 1996)

It should be noted that the methods recommended in literature are often not suitable in a specific country. High temperature incinerators or secure landfills may not be available.

Exposure Limits
	Type of limit	Value
Food	MRLs (Maximum residue limits in mg/kg) in specified products (Codex Alimentarius, 1996)	0.05-2
	JMPR_ADI (acceptable daily intake) in mg/kg diet (Codex Alimentarius, 1995)	0.004
Workplace	USA (NIOSH) TLV-TWA (Threshold Limit Value, Time-weighted average in mg/m3)	0.1

First Aid

Early symptoms of poisoning may include excessive sweating, headache, weakness, giddiness, nausea, vomiting, hypersalivation, stomach pains, blurred vision and slurred speech. If these symptoms occur, the person should remove contaminated clothes, wash the affected skin with soap and water and flush with large quantities of water. If in the event of collapse artificial resuscitation is used, vomit may contain toxic amounts of the substance. In case of ingestion, the stomach should be emptied as soon as possible by careful gastric lavage. Do not induce vomiting if the formulation contained hydrocarbon solvents.

Persons who have been poisoned (accidentally or otherwise) must be transported immediately to a hospital and put under the surveillance of properly trained medical staff.

Antidotes are atropine sulphate and pralidoxime chloride.

General surveillance and cardiac monitoring must be maintained for at least 14 days. (IPCS, 1986)

Annex 1 - further information on the substance

1. Chemical and Physical Properties
1.1	Identity	Pure parathion is a pale yellow liquid.
		The technical grade material is a dark brown colour with a garlic-like odour.
1.2	Formula	C10H14NO5PS
	Chemical Name	O,O-diethyl O-4-nitrophenyl phosphorothioate (IUPAC); O,O-diethyl O-(4-nitrophenyl) phosphorothioate (CAS)
	Chemical Type	Organophosphate
1.3	Solubility	Slightly soluble in water (20-25 mg/l), miscible in most organic solvents, slightly soluble in petroleum oils
	logPow	3.1-3.9
1.4	Vapour Pressure	5.0 mPa (20°C)
1.5	Melting Point	6.1 °C
		Further information in (Tomlin, 1994;, IPCS; 1991, FAO, 1971)
2. Toxicity
2.1 General
2.1.1	Mode of action	Non-systemic insecticide and acaricide with contact, stomach, and some respiratory action. Cholinesterase inhibitor.
2.1.2	Uptake	Parathion is easily absorbed through the skin, as well as by inhalation and via the gastrointestinal tract. (IPCS, 1991)
2.1.3	Metabolism	Parathion is oxidised to paraoxon, a strong inhibitor of acetylcholinesterase. Product of degradation is p-nitrophenol.
2.2 Known Effects on Human Health
2.2.1	Acute Toxicity
	Symptoms of poisoning	Parathion is highly toxic and extremely hazardous. In man, an oral dose of 3- 5 mg/kg b.w. is usually fatal. Signs and symptoms of poisoning develop after a latent period and may continue to increase after exposure has been discontinued.
		Signs and symptoms may include a feeling of exhaustion, headache, blurred vision weakness, and confusion. Vomiting, abdominal pain, excessive sweating and salivating may develop. The pupils are constricted. Difficulty in breathing may be experienced, due to congestion of the lungs and weakness of the respiratory muscles. Arrhytmias and cardiac failure have been reported. In cases of severe poisoning, there will be muscle spasms, unconsciousness, and convulsions. Breathing may stop, followed by death. (IPCS, 1991; IARC, 1979; Hayes, 1991)
2.2.2	Short and long term exposure	Some organophosphates may cause delayed symptoms beginning 1 to 4 weeks after an acute exposure that may or may not have produced immediate symptoms. In such cases, numbness, tingling, weakness and cramping may appear in the lower limbs and progress to incoordination and paralysis. Improvement may occur over months or years, but some residual impairment will remain.
2.2.3	Epidemiological studies	No human data
2.3 Toxicity studies with laboratory animals and in vitro systems
2.3.1	Acute Toxicity
	oral	LD50 (a.i; mg/kg b.w.): 2-12; in different test species. (Tomlin, 1994)
	dermal	LD50 (a.i.; mg/kg b.w.): 50; rat. (Tomlin, 1994)
	inhalation	LC50 (mg/m3 air- exposure 4 hrs): 50; rats (Tomlin, 1994)
	irritation	Not irritating to skin and eyes (rabbits) (Tomlin, 1994)
2.3.2	Short-term exposure	Rats: up to 16 weeks duration showed cholinesterase inhibition at and above 5 mg/kg in the diet, no effect at 1 ppm (0.05 mg/kg b.w./day). (IPCS, 1991) Dogs: at 1,2 and 5 ppm for 24 weeks, slight but significant plasma cholinesterase inhibition observed at the 1 ppm dose (0.021 mg/kg b.w./day).
2.3.3	Effects on reproduction	Parathion produced embryocidal effects and foetal growth retardation, but not malformations, in mice and rats at doses that were generally below the level that was toxic for the mother. (IPCS, 1991)
2.3.4	Mutagenicity	No evidence has been found that parathion is mutagenic.
2.3.5	Carcinogenicity	IARC: Long-term feeding studies in mice and rats have been determined to be inadequate for evaluation of carcinogenicity mainly because of the short treatment duration or inadequate numbers of animals in each dose group. IARC concluded that the data were insufficient to evaluate potential carcinogenicity in humans.
		NTP: The U.S. National Toxicology Program cites "equivocal evidence" of carcinogenicity in rats.
		USA: EPA classifies parathion as a Class C carcinogen (possible human carcinogen). (US-EPA, 1991)
3 Exposure
3.1	Food	Residues are normally well below Codex MRLs (ranging from 0.5-1.0 mg/kg for fruit and vegetables). Extensive monitoring data from several countries indicate that the residues are infrequently found. However, there have been reports of residues in cabbage and mustard greens in Indonesia and frequently detected residues in vegetables in Mexico as well as intoxication and deaths from gross contamination of foodstuffs during transportation with parathion. (IPCS, 1991, US-EPA, 1996)
		A trial on lemons in Portugal reported residues of 0.22 mg/kg 21 days after spraying. Trials in Portugal suggest that when parathion is used according to Good Agricultural Practices, residues in olives should not exceed 0.5 mg/kg.
		Parathion residues in crude olive oil were on average 4.5 times the levels in the olives. Supervised trials in the USA on sorghum suggest a maximum residue level of 5 mg/kg. Paraoxon was detected in every sample. Parathion residues in cottonseed ranged up to 0.97 mg/kg in supervised USA trials. (JMPR, 1993)
3.2	Occupational	Skin contact, inhalation and ingestion are sources of exposure. Applicators and field workers handling recently treated crops are particularly at risk. Use by untrained and poorly equipped applicators can result in poisoning.
		Parathion is the only pesticide for which US EPA has received reports of death resulting from workers re-entering treated fields or wearing contaminated clothing despite laundering. It has accounted for a significant percentage of crop worker poisonings in the USA.
		During mixing operations, levels of up to 5.5 mg/m3, that is higher than the TLV, have been reported.
		EPA's analysis of reports issued by the California Department of Food and Agriculture shows that from 1980-1986 parathion ranked among the highest in reported rate of systemic agricultural poisonings among 45 selected pesticides likely to be used on the same crops. Poisoning from parathion continues to occur even though California requires the most stringent protective measures in the country. (US-EPA, 1991; US-EPA, 1996)
3.3	Environment	Environmental concentrations of parathion are generally low and will be no hazard to human health. In Germany concentrations up to 320 ng/l have been detected in rainwater. (BBA, 1996)
3.4	Accidental Poisoning	Numerous cases of poisoning have been reported involving applicators, field workers re-entering treated areas and grossly contaminated food. (IPCS, 1991) In Parana State, Brazil, pesticides causing more than 10 incidents were analysed in 1990; parathion caused 92 of 412 reported incidents.
4. Effects on the Environment
4.1 Fate
4.1.1	Persistence	Parathion rapidly hydrolyses in alkaline conditions (pH>10) and is hydrolytically stable under sterile conditions at pH 4 - 9.
		Parathion is degraded in soils, plants and other substrates at a moderate rate, though such conversion may be initially to the more toxic metabolite paraoxon. Such conversion is especially true under dry, hot conditions. (IPCS, 1991)
		Parathion has little or no potential to contaminate ground water. (Tomlin, 1994)
4.1.2	Bioconcentration	Parathion does not bioconcentrate.
4.2 Ecotoxicity
4.2.1	Fish	LC50 0.05-27 m g/L EPA, 1991
4.2.2	Aquatic invertebrates	0.04-15m g/L (EPA, 1991)
4.2.3	Birds	LD50 2-30 mg/kg b.w. in various species (EPA, 1991)
4.2.4	Bees	Highly toxic to bees (EPA, 1991)

Annex 2 - details on reported control actions

ANGOLA

Effective
Control Action	Parathion is banned for use.
Uses still allowed
Reasons	Parathion is banned because of its high toxicity.

BELIZE

Effective	1985
Control Action	The substance is banned for use.
Uses still allowed	No remaining uses are allowed.
Reasons	Extremely and acutely toxic; use not warranted.

COLOMBIA

Effective	1991
Control Action	The substance is severely restricted for use. Only the use on cotton is allowed.
Uses still allowed	Use on cotton from aeroplanes.
Reasons	Incorrect utilization of the substance on tobacco, soya, potato and tomato cultures.

INDIA

Effective	1974
Control Action	Banned.
Uses still allowed
Reasons	Due to toxicity.

INDONESIA

Effective
Control Action	Prohibited for all uses.
Uses still allowed	No.
Reasons	Extremely toxic to human and warm blooded animals through inhalation, skin absorption and ingestion. Lts toxicity is enhanced by metabolic oxidation to diethyl 4-nitrophenyl phosphate.

JAPAN

Effective	1955
Control Action	Uses other than those specified by Cabinet Order are prohibited. No use has been designated.
Uses still allowed	Scientific research by authorized researcher.
Reasons	Very strong toxicity.

KUWAIT

Effective	1980
Control Action	Banned for use as a pesticide.
Uses still allowed	No remaining uses allowed
Reasons	Health and environmental reasons.

NEW ZEALAND

Effective	1987
Control Action	Voluntary withdrawal of all products, registrations cancelled.
Uses still allowed	No uses allowed.
Reasons	Human health reasons (acute toxicity).

PORTUGAL

Effective	1994
Control Action	Banned.
Uses still allowed
Reasons	Human health.

SRI LANKA

Effective	1984
Control Action	Banned for use as a pesticide.
Uses still allowed	No remaining uses allowed.
Reasons	Fatal and non-fatal poisoning of farmers.

SWEDEN

Effective	1971
Control Action	Banned for use as a pesticide. The substance is suspended because of its high acute toxicity.
Uses still allowed
Reasons	Because of its high acute toxicity.

TANZANIA, UNITED REPUBLIC OF

Effective	1986
Control Action	Total ban.
Uses still allowed
Reasons	Highly toxic chemicals.

THAILAND

Effective	1988
Control Action	Banned: All agricultural uses. Decision from the Toxic Substance Controlling Board.
Uses still allowed
Reasons	Highly toxic to users.

Annex 3 - list of designated national authorities

ANGOLA

 

P	Phone
Le Coordinateur	Fax
Ministère de l'Agriculture / Cabinet technique Programme	Telex
national de la protection des plantes	e-mail
Avenida Cdt. Gika
Luanda

BELIZE

C	Phone	501-92-2640/92-3772
Sanitation Engineer	Fax	501-92-3772
Ministry of Health Public Health Bureau,	Telex	102 Foreign Bz
Belize City	e-mail
P	Phone
The Secretary	Fax
Pesticides Control Board Department of Agriculture, Mr Mario	Telex
Central Farm Cayo	e-mail

COLOMBIA

P	Phone	57 1 285 5520
Ministerio de Agricultura Instituto Colombiano Agropecuario (ICA),	Fax	57 1 285 4351
Calle 37 No. 8-43 Piso 4 y 5	Telex
Bogotá Apartado aéreo 6984	e-mail
CP	Phone	57 1 245 9228
Jefe	Fax	57 1 282 0003
Ministerio de Salud División Sustancias Potencialmente Tóxicas,	Telex	MINSALUDBOGOTA
Calle 55 No. 10-32 - Bloque B piso 3
Bogotá	e-mail
P	Phone	571 284 2427
Director General	Fax	571 285 9987
Ministerio de Agricultura Instituto Nacional de los Recursos Naturales Renovables,	Telex	44428 INDE
Carrera 10 No. 20-30 Of. 204
Bogotá Apt. aéreo 13458	e-mail

INDIA

C	Phone	91 (11) 3385131
Joint Secretary	Fax	91 (11) 3382176
Ministry of Chemicals and Fertilizers Department of Chemicals and Petrochemicals, Mr. P.C. Rawal	Telex
Rajendra Prasaid Road Shastri Bhavan
110001 New Delhi	e-mail
P	Phone
The Director/Deputy Secretary	Fax
Department of Agriculture and Co-operation Plant Protection Division	Telex
Room No. 244-A
Krishi Bhavan, New Delhi	e-mail

INDONESIA

P
Chairman	Phone	62 (21) 7805652 /7806213
Direktorat Bina Perlindungan Tanaman Pesticide Committee,	Fax	62 (21) 7805652
Jln. AUP. Pasar Minggu	Telex
12520 Jakarta	e-mail
CP	Phone	021 583918
Bapedal Offices , Ms. Masnellyarti Hilman	Fax	021 5703365
Arthaloka Building, 11th Floor, Jl. Jend Sudirman No. 2	Telex	6221583918
Jakarta Pusat	e-mail

JAMAICA

P	Phone
The Registrar	Fax
Ministry of Health Pesticides Control Authority, Mr. Paul Whylie	Telex
10 Caledonia avenue
Kingston P.O. Box 472	e-mail

KUWAIT

P	Phone	(965) 2427161
Public Authority for Agriculture Affairs & Fish Resources Plant Wealth Department	Fax
Safat	Telex
13075 Kuwait P. 0. Box 21422	e-mail
CP	Phone	(965) 2452790 -
The Secretary General		2456835/36
Environment Protection Council	Fax	(965) 2421993
Safat	Telex	46408 EP CNCL KT
13104 Kuwait P. 0. Box 24395	e-mail

NEW ZEALAND

CP	Phone	064 4 528 6089
The Chief Scientist (Pesticides)	Fax	064 4 528 4675
Ministry of Agriculture and Fisheries Agricultural Compounds	Telex
Unit, Mr D.W. Lunn
Upper Hutt P. 0. Box 40-063	e-mail

PORTUGAL

P	Phone	(1) 4412822
Director	Fax	(1) 4420616
Centro Nacional de Protecçao da Produçao Agrícola	Telex	16732 DGPPA
Quinta do Marques
2780 Oeiras	e-mail

SRI LANKA

C	Phone	94 (1) 549455
The Director-General	Fax
Central Environmental Authority	Telex	22775 NHDA
Maligawatte New Town
10 Colombo	e-mail
P	Phone	94 (08) 88135
Registrar of Pesticides
Pesticides Registration Office	Fax	94 (08) 88206
Getambe	Telex
Peradeniya P.O. BOX 49	e-mail

SWEDEN

CP	Phone	46 8 730 6004
The National Chemicals Inspectorate (Keml), Mr. Ule	Fax	46 8 735 7698
Johansson	Telex	10460 AMS S
S-171 27 Solna P. 0. Box 1384	e-mail

TANZANIA, UNITED REPUBLIC OF

CP	Phone	0578813/4/5
Registrar of Pesticides	Fax	0578217
Tropical Pesticides Research Institute	Telex	42002 TPRI TZ
Arusha P.O. Box 3024	e-mail
P	Phone	0578813/4/5
The Registrar of Pesticides	Fax	0578217
Tropical Pesticide Research Institute , Mr. H.A. Lyatuu	Telex	42002 TPRI TZ
Arusha 3024	e-mail
C	Phone	255 51 29406,25021/2
The Chief Government Chemist	Fax	255 51 39951
Government Chemical Laboratory , Ms. Mpore	Telex
Dar-es-Salaam P.O. Box 164	e-mail

THAILAND

P	Phone	66 (2)5790586,
Director-General		579 9636
Ministry of Agriculture and Co-operatives Department of Agriculture,	Fax Telex
Rajadamnern Ave.	e-mail
10200 Bangkok
CP	Phone	66 (2) 6192296
Director	Fax	66 (2) 6192297
Pollution Control Department Hazardous Substances and Waste Management Division	Telex
404 Phahon Yothin Center Bldg., Phahon Yothin Rd. Sam Sen	e-mail
Nai
10400 Bangkok

C	Industrial and consumer product chemicals
CP	Pesticides
P	Pesticides, industrial and consumer product chemicals

Annex 4 - References

The information on parathion given in this DGD is mainly based on documents published by WHO, FAO and the International Programme on Chemical Safety (IPCS). If important information from other sources has been used, these references are noted in the text. The following list also includes other publications containing useful information.

Codex Alimentarius Commission 1996. Codex Alimentarius, Volume 2 B, Pesticide residues in food - Maximum residue limits Joint FAO/WHO Food Standards Programme, Rome.

Dinham, Barbara, 1993. The Pesticide Hazard: A Global Health and Environmental Audit Zed Books, London and New Jersey.

FAO, 1995. Guidelines on Prevention of Accumulation of Obsolete Pesticides in Developing Countries. Food and Agriculture Organization, Rome.

FAO, 1996. Pesticide storage and stock control manual. Food and Agriculture Organization, Rome.

FAO, 1996. Technical guidelines on disposal of bulk quantities of obsolete pesticides in developing countries. Food and Agriculture Organization, Rome.

FAO, 1995. Revised guidelines on good labelling practices for pesticides. Food and Agriculture Organization, Rome.

FAO, 1990. Guidelines for personal protection when working with pesticides in tropical countries. Food and Agriculture Organization, Rome.

FAO, 1971. Specifications for plant protection products: parathion. AGP:CP/32, Food and Agriculture Organization, Rome.

FAO/WHO, 1975. Data sheets on pesticides No. 6: parathion. Food and Agriculture Organization/World Health Organization, Rome, Geneva.

FAO/WHO, 1969. Pesticide Residues in Food - 1969; The Monographs. Joint Meeting on Pesticide Residues (JMPR); WHO, Geneva, Rome.

FAO/WHO, 1993. Pesticide Residues in Food - Evaluations. Methamidophos. Joint Meeting on Pesticide Residues (JMPR), Geneva, Rome.

Farm Chemicals Handbook 1994. Meister Publishing, Willoughby, Ohio, USA.

Forget, G., Goodman J. and A. de Villiers, 1990. Impact of Pesticide Use on Health in Developing Countries. International Developing Research Center.

Gips, T., 1990. Breaking the pesticide habit: alternatives to 12 hazardous pesticides. IASA/IOCU, Malaysia.

Hayes, W.J. and E.R. Laws (ed.), 1990. Handbook of Pesticide Toxicology, Vol. 3, Classes of Pesticides. Academic Press, Inc., NY.

Howard, P.H. (ed.), 1989. Handbook of Environmental Fate and Exposure Data for Organic Chemicals, Vol. III. Pesticides. Lewis Publishers, Chelsea, M.

IARC, 1979. The IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans. Occupational Exposures in Insecticide Application and Some Pesticides. International Agency for Research on Cancer. Vol 20, Lyon, France.

IPCS, 1986. Environmental health criteria No. 63: Organophosphorous insecticides: a general introduction. International Programme on Chemical Safety, IPCS/ World Health Organization, Geneva.

IPCS, 1991. Health and safety guide: parathion. Draft World. International Programme on Chemical Safety, IPCS/ World Health Organization, Geneva.

Tomlin, Clive 1994. The Pesticide Manual: A World Compendium. (10th ed.), British Crop Protection Council, Surrey, (United Kingdom)

US-EPA 1991. Ethyl parathion, Receipt of Requests for Cancellation Federal Register, Vol. 56, No 240. US Environmental Protection Agency. USEPA, Washington, DC, USA.

US-EPA, 1992. Ethyl parathion, Amendment of Cancellation Order. Federal Register Col 57, No 19.

US-EPA, 1996. Literature Survey on Poisoning Cases Due to Parathion Internal report. US Environmental Protection Agency. USEPA, Washington, DC, USA.

US-EPA, 1991. Settlement Agreement for parathion: Voluntary cancellation of most uses: remaining field crop uses severely restricted.

US-EPA, 1986. Pesticide Fact Sheet, no. 116: parathion. US Environmental Protection Agency. USEPA, Washington, DC, USA.

WHO, 1996. Recommended classification of pesticides by hazard and guidelines to classification 1996-1997. WHO/PCS/96.3. World Health Organization, IPCS, Geneva.