Parathion-ethyl (Ref: OMS 19)	Last updated: 25/02/2021
(Also known as: parathion; thiophos; ethyl parathion; BAY 9491; ENT 15108; AC 3422)

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GENERAL INFORMATION

Description	A broad-spectrum insecticide and acaricide used to control sucking and chewing insects and mites
Example pests controlled	Aphids; Mealybugs; Codling moth; Scale, Leafhoppers
Example applications	Alfalfa; Barley; Rapseed; Cotton; Sorghum; Soybeans; Sunflowers; Wheat; Broccoli; Brussel sprouts
Efficacy & activity	-
Availability status	Obsolete. Banned in many countries.
Introduction & key dates	circa 1950

UK regulatory status

UK COPR regulatory status	Not approved
Date COPR inclusion expires	Expired
UK LERAP status	No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status	Not approved
Dossier rapporteur/co-rapporteur	Italy
Date EC 1107/2009 inclusion expires	Expired
EU Candidate for substitution (CfS)	Not applicable
Listed in EU database	Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States	ATAustria BEBelgium BGBulgaria CYCyprus CZCzech Republic DEGermany DKDenmark EEEstonia ELGreece                   ESSpain FIFinland FRFrance HRCroatia HUHungary IEIreland ITItaly LTLithuania LULuxembourg                   LVLatvia MTMalta NLNetherlands PLPoland PTPortugal RORomania SESweden SISlovenia SKSlovakia

Also used in

Also used in	-

Chemical structure

Isomerism	None
Chemical formula	C₁₀H₁₄NO₅PS
Canonical SMILES	CCOP(=S)(OCC)OC1=CC=C(C=C1)[N+](=O)[O-]
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	LCCNCVORNKJIRZ-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C10H14NO5PS/c1-3-14-17(18,15-4-2)16-10-7-5-9(6-8-10)11(12)13/h5-8H,3-4H2,1-2H3
2D structure diagram/image available?	Yes

General status

Pesticide type	Insecticide, Acaricide
Substance group	Organophosphate
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Non-systemic with contact, stomach and some respiratory action. Acetylcholinesterase (AChE) inhibitor.
CAS RN	56-38-2
EC number	200-271-7
CIPAC number	10
US EPA chemical code	057501
PubChem CID	991
Molecular mass	291.27
PIN (Preferred Identification Name)	O,O-diethyl-O-4-nitrophenyl phosphorothioate
IUPAC name	O,O-diethyl O-4-nitrophenyl phosphorothioate
CAS name	O,O-diethyl O-(4-nitrophenyl) phosphorothioate
Other status information	PIC Annex III; Potential groundwater contaminant; Marine Pollutant; Rotterdam Convention (Class Ia)
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	Not applicable
Herbicide Resistance Classification (WSSA)	Not applicable
Insecticide Resistance Classification (IRAC)	1B
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	Adoxophyes orana, Aedes dorsalis, Aedes melanimon, Aedes nigromaculis, Amblyseius potentillae, Bemisia tabaci, many others
Physical state	White crystalline solid with foul odour when pure. technical substance may be a pale yellow liquid
Related substances & organisms	parathion-methyl

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Folidol E Niran Woprophos Fighter Co-thion Alkron Vitrex
Example products using this active	Bayer Crop Protection Monsanto Cheminova King Tech Fujian Sannong Group Co. Ltd.
Formulation and application details	Available in a variety of formulations including dusts, emulsion concentrates, granules, ULV liquids and wettable powders

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		12.4	G4 G = Extension Toxicology network database EXTOXNET (click here ) 4 = Verified data	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		200000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Dichloromethane	-
		200000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Toluene	-
		75000	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source Hexane	-
		200000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Isopropanol	-
Melting point (°C)		6.1	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Boiling point (°C)		375	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		174	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Octanol-water partition coefficient at pH 7, 20 °C	P	6.76 X 1003	Calculated	-
	Log P	3.83	G4 G = Extension Toxicology network database EXTOXNET (click here ) 4 = Verified data	High
Bulk density (g ml⁻¹)		1.26	AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here ) 4 = Verified data	-
Dissociation constant pKa) at 25 °C		-	-	-
		-
Vapour pressure at 20 °C (mPa)		0.89	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		3.02 X 10-02	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Non-volatile
Maximum UV-vis absorption L mol⁻¹ cm⁻¹		-	-	-
Surface tension (mN m⁻¹)		-	-	-

Degradation

Property		Value	Source; quality score; and other information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT₅₀ (typical)	49	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Moderately persistent
	DT₅₀ (lab at 20 °C)	14	F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source	Non-persistent
	DT₅₀ (field)	17	AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here ) 4 = Verified data	Non-persistent
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	ICULID datasheet DT₅₀ lab studies 3-32 days, field studies DT₅₀ range 2-58 days; Other sources: 7DT₅₀ -10 days (R3)
Dissipation rate RL₅₀ on plant matrix	Value	3.8	R4 R = Peer reviewed scientific publications 4 = Verified data	-
	Note	Published literature RL₅₀ range 0.2-19.6 days, wide range of field grown crops and wide range of matrics, n=30
Dissipation rate RL₅₀ on and in plant matrix	Value	5.1	-	-
	Note	Published literature RL₅₀ range 0.7-31.1 days, wide range of field grown crops and wide range of matrics, n=32
Aqueous photolysis DT₅₀ (days) at pH 7	Value	30	AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here ) 4 = Verified data	Stable
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	260	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Persistent
	Note	pH sensitive: DT₅₀ 272 days at pH 4, 130 days at pH 9, all at 22 °C
Water-sediment DT₅₀ (days)		4.3	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Fast
Water phase only DT₅₀ (days)		3.5	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Moderately fast

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	H3 H = The US ARS pesticide properties database (click here ) 3 = Unverified data of known source	Non-mobile
	Koc	7660
	Notes and range	Other sources: 316.2-15849 mL g⁻¹ (R3)
Freundlich	Kf	17	R4 R = Peer reviewed scientific publications 4 = Verified data	Slightly mobile
	Kfoc	580
	1/n	0.95
	Notes and range	Kf range 13.0-21.0 (229 for peat) mL g⁻¹, Kfoc range 491-636 (355 for peat) mL g⁻¹, 1/n - no data, Soils=4
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		1.52	Calculated	Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	3.32 X 10-02	Calculated	-
	Note	-
Potential for particle bound transport index		Medium	Calculated	-
Potential for loss via drain flow		Non-mobile	Calculated	-

ECOTOXICOLOGY

Property		Value	Source; quality score; and other information	Interpretation
Bio-concentration factor	BCF (l kg⁻¹)	40	P4 P = Other governments and regulators 4 = Verified data (Other literature values Log BCF range 1.1-1.9 (R3))	Low potential
	CT₅₀ (days)	<0.5		-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		2	G4 G = Extension Toxicology network database EXTOXNET (click here ) 4 = Verified data Rat	High
Mammals - Short term dietary NOEL	(mg kg⁻¹)	-	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source Rat 2 year	-
	(ppm diet)	2		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		2.1	G4 G = Extension Toxicology network database EXTOXNET (click here ) 4 = Verified data Anas platyrhynchos	High
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		1.5	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Oncorhynchus mykiss	Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)		> 0.098	P3 P = Other governments and regulators 3 = Unverified data of known source Danio rerio	Moderate
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		0.0025	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Daphnia magna	High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		0.0001	P3 P = Other governments and regulators 3 = Unverified data of known source Daphnia magna	High
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)		0.00011	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Americamysis bahia	High
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)		0.14	F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source Chironomus riparius 1 day	Moderate
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)		-	-	-
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		10.0	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Scenedemus subspicatus	Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		-	-	-
Honeybees (Apis spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	> 0.21	R4 R = Peer reviewed scientific publications 4 = Verified data	High
	Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	> 0.175	F2 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 2 = Unverified data of unknown source Apis mellifera	High
Bumblebees (Bombus spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
Mason bees (Osmia spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
Other pollinators (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other pollinators (2)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		> 267	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Eisenia foetida	Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)		-	-	-
Other soil macro-organisms	Acute LC₅₀ (mg kg⁻¹)	-	-	-
	Chronic NOEC (mg kg⁻¹)	-	-	-
Other arthropod (1)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	Harmful	AB1 AB = SELECTV Database 1 = Estimated data with little or no verification Typhlodromus pyri	-
Other arthropod (2)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	-	-	-
Soil micro-organisms		-	-	-
Mesocosm study data	NOEAEC mg l⁻¹	-	-	-
	NOEAEC mg l⁻¹	-	-	-

HUMAN HEALTH AND PROTECTION

General

Property		Value	Source; quality score; and other information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		2	G4 G = Extension Toxicology network database EXTOXNET (click here ) 4 = Verified data Rat	High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		71.0	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		0.03	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat (aerosol)	-
Other Mammal toxicity endpoints		-	-	-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)		0.0006	A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes	-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)		0.005	A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)		-	-	-
Dermal penetration studies (%)		-	-	-
Dangerous Substances Directive 76/464		List I; List II	-	-
Exposure Routes	Public	-
	Occupational	-
MRLs	European	EU MRL pesticide database
	Notes	-
Drinking Water Standards		EU Drinking Water standards: A1 waters: 0.001 mg l⁻¹, A2 waters 0.0025 mg l⁻¹, A3 waters: 0.005 mg l⁻¹ EU Directive for the protection of shelfish intended for human consumption: 100 µg l⁻¹	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes UK EA QS database 2018	-
Drinking Water MAC (μg l⁻¹)		-	-	-

Health issues

Specific human health issues		Carcinogen Genotoxic Endocrine disruptor ?Possibly, status not identified A0 A = Chromosome aberration (EFSA database) 0 = No data ; B0 B = DNA damage/repair (EFSA database) 0 = No data ; C0 C = Gene mutation (EFSA database) 0 = No data ; D0 D = Genome mutation (EFSA database) 0 = No data ; E1 E = Unspecified genotoxicity type (miscellaneous data source) 1 = Positive ?Possibly, status not identified Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant ✓Yes, known to cause a problem No data found XNo, known not to cause a problem Respiratory tract irritant Skin irritant Skin sensitiser ✓Yes, known to cause a problem ✓Yes, known to cause a problem XNo, known not to cause a problem Eye irritant Phototoxicant   ✓Yes, known to cause a problem No data found
General human health issues		Highly toxic Possible brain toxicant USEPA - possible human carcinogen

Handling issues

Property	Value and interpretation
General	IMDG Transport Code is usually 6.1
CLP classification 2013	Health: H300, H311, H330, H372 Environment: H400, H410
EC Risk Classification	T+ - Very toxic: R26/28 T - Toxic: R24, R48/25 N - Dangerous for the environment: R50, R53
EC Safety Classification	S1/2, S28, S36/37, S45, S60, S61
WHO Classification	Ia (Extremely hazardous)
UN Number	3018
Waste disposal & packaging	Packaging Group I (great danger)

TRANSLATIONS

Language	Name
English	parathion-ethyl
French	parathion
German	Parathion
Danish	parathion
Italian	paration
Spanish	paratión
Greek	parathion
Polish	paration
Swedish	-
Hungarian	-
Dutch	parathion

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Record last updated:	25/02/2021
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242