(Also known as: M 74; ethylhiometon; thiodemeton; dithiodemeton; dithiosystox)
SUMMARY
Disulfoton is an organothiophosphate insecticide and acaricide that is not approved for use in the EU. It has a low aqueous solubility, is moderately volatile and, based on its chemical properties it would not normally be expected to leach to groundwater. It can be persistent in some soil systems but would not normally be persistent in water bodies. It is highly toxic to mammals, a cholinesterase inhibitor, a neurotoxicant and there are some concerns regarding its carcinogenicity. It is moderately or highly toxic to most fauna.
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
Ecotoxicity High alert: Birds acute ecotoxicity: High; Fish acute ecotoxicity: High; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High; Bees acute contact ecotoxicity: High
Human health High alert: Mammals acute toxicity: High; Acetyl cholinesterase inhibitor; Neurotoxicant
GENERAL INFORMATION
Description
An organophosphate aphicide and insecticide used to sucking insects on agricultural crops
Solubility - In organic solvents at 20 °C (mg l⁻¹)
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
n-Hexane
-
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Dichloromethane
-
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Isopropanol
-
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Toluene
-
Melting point (°C)
-25
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Boiling point (°C)
-
-
-
Degradation point (°C)
-
-
-
Flashpoint (°C)
133
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
8.91 X 1003
Calculated
-
Log P
3.95
H4 H = The US ARS pesticide properties database. Dataset is no longer available. 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
H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data
Moderately volatile. If applied directly to plants or soil, drift is a concern & mitigation is advisable
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
1.60 X 10-01
H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data
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)
30
M4 M = GLEAMS Model database (Groundwater Loading Effects of Agricultural Management Systems). Dataset no longer available. 4 = Verified data
Moderately persistent
DT₅₀ (lab at 20 °C)
2
M4 M = GLEAMS Model database (Groundwater Loading Effects of Agricultural Management Systems). Dataset no longer available. 4 = Verified data
Non-persistent
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
Best available data
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
4
P2 P = Other non-EU, UK or US Governments and Regulators 2 = Unverified data of unknown source
Moderately fast
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
300
P3 P = Other non-EU, UK or US Governments and Regulators 3 = Unverified data of known source
Persistent
Note
-
Water-sediment DT₅₀ (days)
15
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
Fast
Water phase only DT₅₀ (days)
15
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
Slow
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
[Milled, toasted maize flour (gofio): 33 days @ dark, ambient conditions; Field study], [Milled, toasted wheat flour (gofio): 24 days @ dark, ambient conditions; Field study]
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
Slightly mobile
Koc (mL g⁻¹)
1345
Notes and range
Other sources: 600 mL g⁻¹ (DW3)
Freundlich
Kf (mL g⁻¹)
39.5
Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source
-
Kfoc (mL g⁻¹)
-
1/n
1.09
Notes and range
General literature data: Kf range 15.5-24.3 mL g⁻¹, mean of 8 values for 2 loam soils.
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
0.26
Calculated
Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
6.29 X 10-04
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
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
4.1
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
Apis mellifera
Moderate
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
Chronic
-
-
-
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 1.0
R3 R = Peer reviewed scientific publications 3 = Unverified data of known source
Bombus spp.
Moderate
Literature values range 1.0-6.0 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)
0.039
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Lepomis macrochirus
High
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
0.22
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
Oncorhynchus mykiss 35 day LOEC
Moderate
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 100
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
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
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
-
-
-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
0.036
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
Unknown species
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
0.01
Q1 Q = Miscellaneous data from online sources 1 = Estimated data with little or no verification
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