(Also known as: parathion; thiophos; ethyl parathion; BAY 9491; ENT 15108; AC 3422)
SUMMARY
Data alerts
The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.
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
CLP index number
015-034-00-1
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
Potential groundwater contaminant; Marine Pollutant; Rotterdam Convention (Class Ia) - subject to PIC regulations Annex III; Subject to the provisions of the UK Poisons Act 1972
Example manufacturers & suppliers of products using this active now or historically
Bayer Crop Protection
Monsanto
Cheminova
King Tech
Fujian Sannong Group Co. Ltd.
Example products using this active
Folidol E
Niran
Woprophos
Fighter
Co-thion
Alkron
Vitrex
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. Available online but no longer updated. (click here ) 4 = Verified data
Moderate
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. Available online but no longer updated. (click here ) 4 = Verified data
High
Fat solubility of residues
Solubility
Soluble
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
-
Data type
Regulatory data - observed in metabolism and farm animal feeding studies
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
-
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. If applied directly to plants, drift is a concern & mitigation is advisable
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
Volatilisation as max % of applied dose lost
From plant surface
-
-
-
From soil surface
-
-
-
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; these datasets no longer available). Norman Ecotoxicology database. (click here ) 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 / FAO data, IPCS INCHEM data (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 (days) 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 (days) 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; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data
Fast
Water phase only DT₅₀ (days)
3.5
K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data
Moderately fast
Sediment phase only DT₅₀ (days)
-
-
-
Air degradation
As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.
Decay in stored produce DT₅₀
-
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
-
H3 H = The US ARS pesticide properties database. Dataset is no longer available. 3 = Unverified data of known source
Non-mobile
Koc (mL g⁻¹)
7660
Notes and range
Other sources: 316.2-15849 mL g⁻¹ (R3)
Freundlich
Kf (mL g⁻¹)
17
R4 R = Peer reviewed scientific publications 4 = Verified data
Slightly mobile
Kfoc (mL g⁻¹)
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
Low
Calculated
-
Potential for loss via drain flow
Non-mobile
Calculated
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
-
-
-
Bio-concentration factor
BCF (l kg⁻¹)
40
P4 P = Other non-EU, UK or US Governments and Regulators 4 = Verified data
(Other literature values Log BCF range 1.1-1.9 (R3))
Low potential
CT₅₀ (days)
<0.5
-
Known metabolites
None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
13
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source
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 yr
-
(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. Available online but no longer updated. (click here ) 4 = Verified data
Anas platyrhynchos
High
Birds - Short term dietary (LC₅₀/LD₅₀)
-
-
-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
-
-
-
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)
-
-
-
Soil micro-organisms
-
-
-
Collembola
Acute LC₅₀ (mg kg⁻¹)
-
-
-
Chronic NOEC (mg kg⁻¹)
-
-
-
Non-target plants
-
-
-
-
-
-
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
Apis mellifera
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 / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) 2 = Unverified data of unknown source
Apis mellifera
High
Chronic
-
-
-
Notes
[The residual time to 25% mortality (RT25) value for honeybees is 24 hrs - USEPA data]
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 bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
-
-
-
Mode of exposure
-
Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
-
-
-
Mode of exposure
-
Beneficial insects (Ladybirds)
-
-
-
Beneficial insects (Lacewings)
-
-
-
Beneficial insects (Parasitic wasps)
-
-
-
Beneficial insects (Predatory mites)
Harmful
Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source
Typhlodromus pyri
-
Beneficial insects (Ground beetles)
-
-
-
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater 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
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
> 0.098
P3 P = Other non-EU, UK or US Governments and Regulators 3 = Unverified data of known source
Danio rerio
Moderate
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (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)
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source
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
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; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here ) 5 = Verified data used for regulatory purposes
UK EA QS database 2018
-
Drinking Water MAC (μg l⁻¹)
-
-
-
Mammalian dose elimination route and rate
-
-
-
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 US EPA - Group C carcinogen, possible human carcinogen
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
Environmental fate
Ecotoxicity
