Chlormephos is an organophosphorus insecticide. It has a moderate aqueous solubility and is not volatile. based on its chemical properties it would not normally be expected to leach to groundwater. It is not normally persistent in soil systems. It is highly toxic to mammals if ingested, inhaled or absorbed through skin , a cholinesterase inhibitor and a neurotoxicant. Ecotoxicology data is sparse but chlormephos is highly toxic to honeybees and moderately toxic to birds, fish and earthworms.
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.
Environmental fate
Ecotoxicity
Human health
Environmental fate Moderate alert: Drainflow: Slightly mobile; Potential for particle bound transport: Medium
Warning: Significant data are missing
Ecotoxicity High alert: Bees acute unknown ecotoxicity: High
Warning: Significant data are missing
Human health High alert: Mammals acute toxicity: High; Acetyl cholinesterase inhibitor; Neurotoxicant
Warning: Significant data are missing
GENERAL INFORMATION
Description
An insecticide used to control a wide range of foliage and soil dwelling pests
Non-systemic with contact and stomach action. Acetylcholine esterase inhibitor.
CAS RN
24934-91-6
EC number
246-538-1
CIPAC number
337
US EPA chemical code
295300
PubChem CID
32739
CLP index number
015-114-00-6
Molecular mass
234.70
PIN (Preferred Identification Name)
S-(chloromethyl) O,O-diethyl phosphorodithioate
IUPAC name
S-chloromethyl O,O-diethyl phosphorodithioate
CAS name
S-(chloromethyl) O,O-diethyl phosphorodithioate
Other status information
Marine Pollutant; Chemical subject to PIC regulations
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Class (HRAC MoA class)
Not applicable
Herbicide Resistance Class (WSSA MoA class)
Not applicable
Insecticide Resistance Class (IRAC MoA class)
1B
Fungicide Resistance Class (FRAC MOA class)
Not applicable
Examples of recorded resistance
None identified
Physical state
Colourless liquid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
Bayer CropScience
Rhone Poulenc
Murphy
Example products using this active
Dotan
Formulation and application details
Usually supplied in a granular formulations
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
60
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 2 = Unverified data of unknown source
Acetone
-
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 2 = Unverified data of unknown source
Methanol
-
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 2 = Unverified data of unknown source
Ethanole
-
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 2 = Unverified data of unknown source
Xylene
-
Melting point (°C)
-
-
-
Boiling point (°C)
-
-
-
Degradation point (°C)
-
-
-
Flashpoint (°C)
-
-
-
Octanol-water partition coefficient at pH 7, 20 °C
P
1.10 X 1003
Calculated
-
Log P
3.04
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
High
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
1.26
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
-
-
-
-
Vapour pressure at 20 °C (mPa)
0.0076
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)
2.97 X 1001
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Moderately 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)
20
W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available. 4 = Verified data
Non-persistent
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
Other sources: DT₅₀ 28 days, sandy soil (R4)
Dissipation rate RL₅₀ (days) on plant matrix
Value
-
-
-
Note
-
Dissipation rate RL₅₀ (days) on and in plant matrix
Value
-
-
-
Note
-
Aqueous photolysis DT₅₀ (days) at pH 7
Value
-
-
-
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
-
-
-
Note
-
Water-sediment DT₅₀ (days)
-
-
-
Water phase only DT₅₀ (days)
-
-
-
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)
-
V1 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 1 = Estimated data with little or no verification
Slightly mobile
Koc (mL g⁻¹)
1100
Notes and range
Estimated
Freundlich
Kf (mL g⁻¹)
-
-
-
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
1.25
Calculated
Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
2.49 X 10-02
Calculated
-
Note
-
Potential for particle bound transport index
Medium
Calculated
-
Potential for loss via drain flow
Slightly mobile
Calculated
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
-
-
-
Bio-concentration factor
BCF (l kg⁻¹)
120
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
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)
-
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Rat
-
(ppm diet)
> 0.39
-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Birds - Acute LD₅₀ (mg kg⁻¹)
260
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Coturnix japonica
Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)
-
-
-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
-
-
-
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
> 1.0
R4 R = Peer reviewed scientific publications 4 = Verified data
Eisenia andrei LOEC
Moderate
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)
-
-
-
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 0.9
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
High
Chronic
-
-
-
Notes
-
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)
-
-
-
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)
2.5
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
Rasbora heteromorpha
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
-
-
-
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
