(Also known as: chlorthiofos; CM S-2957; celathion; OMS 1342; S 2597)
SUMMARY
Chlorthiophos is an obsolete organophosphate insecticide used mainly for the control of ants and mites. The substance has not been extensively studied and so very little data is available. Chlorthiophos is non-volatile and considered to be non-mobile. It is highly toxic to mammals, is a cholinesterase inhibitor and a neurotoxin.
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.
reaction mixture of the three isomers: (i) O-[2,4-dichloro-5-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate; (ii) O-[2,5-dichloro-4-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate (major component); and (iii) O-[4,5-dichloro-2-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate
IUPAC name
mix of (i) O-2,4-dichlorophenyl-5-methylthiophenyl O,O-diethyl phosphorothioate; (ii) O-2,5-dichlorophenyl-4-methylthiophenyl O,O-diethyl phosphorothioate (major component); and (iii) O-4,5-dichlorophenyl-2-methylthiophenyl O,O-diethyl phosphorothioate
Example manufacturers & suppliers of products using this active now or historically
Shell Agrar
Celamerck
Example products using this active
Celathion
Formulation and application details
Was available in a wide variety of formulations including emulsifiable concentrates, dry powders, granules and wettable powders
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
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Solubility - In organic solvents at 20 °C (mg l⁻¹)
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Melting point (°C)
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Boiling point (°C)
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Degradation point (°C)
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Flashpoint (°C)
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Octanol-water partition coefficient at pH 7, 20 °C
P
2.19 X 1004
Calculated
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Log P
4.34
Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source
High
Fat solubility of residues
Solubility
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Data type
-
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Density (g ml⁻¹)
1.46
Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source
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Dissociation constant pKa) at 25 °C
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Vapour pressure at 20 °C (mPa)
0.122
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 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)
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Volatilisation as max % of applied dose lost
From plant surface
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From soil surface
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Maximum UV-vis absorption L mol⁻¹ cm⁻¹
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Surface tension (mN m⁻¹)
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Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
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Soil degradation (days) (aerobic)
DT₅₀ (typical)
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DT₅₀ (lab at 20 °C)
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DT₅₀ (field)
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DT₉₀ (lab at 20 °C)
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DT₉₀ (field)
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DT₅₀ modelling endpoint
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Note
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Dissipation rate RL₅₀ (days) on plant matrix
Value
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Note
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Dissipation rate RL₅₀ (days) on and in plant matrix
Value
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Note
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Aqueous photolysis DT₅₀ (days) at pH 7
Value
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Note
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Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
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Note
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Water-sediment DT₅₀ (days)
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Water phase only DT₅₀ (days)
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Sediment phase only DT₅₀ (days)
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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
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Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
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Q1 Q = Miscellaneous data from online sources 1 = Estimated data with little or no verification
Non-mobile
Koc (mL g⁻¹)
5461
Notes and range
Estimated
Freundlich
Kf (mL g⁻¹)
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Kfoc (mL g⁻¹)
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1/n
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Notes and range
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pH sensitivity
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Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
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SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
Cannot be calculated
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Note
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Potential for particle bound transport index
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Potential for loss via drain flow
Non-mobile
Calculated
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Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
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Bio-concentration factor
BCF (l kg⁻¹)
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CT₅₀ (days)
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Known metabolites
None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
7.8
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Rat
High
Mammals - Short term dietary NOEL
(mg kg⁻¹)
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(ppm diet)
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Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
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Birds - Acute LD₅₀ (mg kg⁻¹)
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Birds - Short term dietary (LC₅₀/LD₅₀)
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Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
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Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
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Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
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Soil micro-organisms
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Collembola
Acute LC₅₀ (mg kg⁻¹)
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Chronic NOEC (mg kg⁻¹)
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Non-target plants
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Honeybees (Apis spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Chronic
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Notes
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Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Mason bees (Osmia spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
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Other bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
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Mode of exposure
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Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
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Mode of exposure
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Beneficial insects (Ladybirds)
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Beneficial insects (Lacewings)
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Beneficial insects (Parasitic wasps)
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Beneficial insects (Predatory mites)
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Beneficial insects (Ground beetles)
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Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
1.3
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Lepomis macrochirus
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
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Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
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
Warning:
Ecotoxicity
Human health
