(Also known as: R(+)-cysteine; thioserine; R-cysteine; free cycteine)
Hazard alerts
The following Pesticide Hazard Tricolour (PHT) 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. The alerts for Highly Hazardous Pesticides (HHPs) are based on applying the FAO/WHO (Type 1) and the PAN (Type II) criteria to PPDB data. Further details on the HHP indicators are given in the tables below. Neither the PHT nor the HHP hazard alerts take account of usage patterns or exposure, thus they do not represent risk.
PHT: Environmental fate
PHT: Ecotoxicity
PHT: Human health
Highly Hazardous Pesticide
Human health Moderate alert: Mammals acute toxicity: Moderate
GENERAL INFORMATION
Description
L-cysteine is a non-essential amino acid which can be used for the control of leaf cutting ants
Example pests/issues controlled
Leaf cutting ants
Example applications
Crop production; Forestry
Efficacy & activity
-
Appearance and life cycle
-
Taxonomic classification
-
GB regulatory status
GB COPR regulatory status
Approved
Date COPR inclusion expires
Open ended
GB LERAP status
None
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Approved
Dossier rapporteur/co-rapporteur
-
Date EC 1107/2009 inclusion expires
Open ended
EU Candidate for substitution (CfS)
No
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
✓
✓
✓
✓
✓
✓
✓
✓
✓
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries
Example manufacturers & suppliers of products using this active now or historically
Wacker Chemie AG
Greenchem Biotech
Example products using this active
Formulation and application details
Used as a mixture with matrix (wheat flour, food grade)
Commercial production
L-cysteine is commercially produced through several methods, with microbial fermentation now being the most widely adopted approach. In this process, genetically engineered bacteria such as Escherichia coli or Corynebacterium glutamicum are cultivated in bioreactors under controlled conditions using inexpensive carbon sources like glucose and nitrogen sources such as ammonium salts. These microbes are optimised to overexpress key enzymes and suppress degradation pathways, enhancing L-cysteine yield. After fermentation, the broth undergoes downstream processing including filtration, ion-exchange chromatography, and crystallisation to isolate and purify the amino acid. Historically, L-cysteine was extracted from animal sources like hair or feathers via acid hydrolysis, but concerns over safety, ethics, and consistency have shifted the industry toward biotechnological production.
Impact on climate of production and use
As microbial-based products tend to use fermentation-based production processes rather than chemical synthesis, they typically have a lower fossil fuel input in formulation and active ingredient creation, and also have reduced downstream emissions due to biodegradability and minimal soil disruption, their life-cycle GHG emissions are expected to be low. Whilst hard and precise data is not available, broad estimates suggest that typically emissions are likely to be below 5 kg CO₂e/kg.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C at pH 7 (mg l⁻¹)
280000
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
as HCl variant
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
-
-
-
Melting point (°C)
174.1
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
as HCl variant
-
Boiling point (°C)
Decomposes before boiling
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
as HCl variant
-
Degradation point (°C)
260
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
as HCl variant
-
Flashpoint (°C)
-
-
-
Octanol-water partition coefficient at pH 7, 20 °C
P
3.24 X 10-03
Calculated
-
Log P
-2.49
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
as HCl variant
Low
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
-
-
-
Dissociation constant pKa) at 25 °C
-
-
-
-
Vapour pressure at 20 °C (mPa)
-
-
-
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
-
-
-
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
Rapidly biodegradable
Soil degradation (days)
DT₅₀ (typical)
-
-
-
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
-
Soil mineralisation
Aerobic (at 20 °C)
-
-
-
Anaerobic (at 20 °C)
-
-
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)
-
-
-
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
-
-
-
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Known metabolites
None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 1800
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
Rat
Moderate
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)
Note: These RTLs have been calculated using the regulatory approach used in the European Union and based on ecotoxocity values in the PPDB.
Species group
RTL
Notes
Mammals
180
Worst case of acute and chronic mammals
Birds
No data
No data for acute and chronic birds
Soil organisms
No data
No data for acute and chronic earthworms
Terrestrial plants
No data
No data for non-target plants vegetative vigour and seedling emergence
Pollinators
No data
No data for contact and oral honeybees
Arthropods
No data
No data for parasitic wasps and predatory mites
Fish
No data
No data for temperate acute and chronic fish
Aquatic invertebrates
No data
No data for temperate acute and chronic aquatic invertebrates
Aquatic plants
No data
No data for free-floating plants, rooted plants, acute and chronic algae
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
Low (class I)
-
-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 1800
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
Rat
Moderate
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
-
-
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
-
-
-
Other Mammal toxicity endpoints
-
-
-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
None allocated
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)
None allocated
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
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
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
-
Dermal penetration studies (%)
-
-
-
Dangerous Substances Directive 76/464
-
-
-
Exposure Routes
Public
No risks identified
Occupational
No risks identified
Mammalian dose elimination route and rate
-
-
-
Health issues
Specific human health issues (hazard-based)
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source) 0 = No data
XNo, known not to cause a problem
Reproduction / development effects
Acetyl cholinesterase inhibitor
Neurotoxicant
XNo, known not to cause a problem
XNo, known not to cause a problem
XNo, known not to cause a problem
Respiratory tract irritant
Skin irritant
Skin sensitiser
XNo, known not to cause a problem
XNo, known not to cause a problem
XNo, known not to cause a problem
Eye irritant
Phototoxicant
✓Yes, known to cause a problem
XNo, known not to cause a problem
General human health issues
Serious eye irritant
Handling issues
Property
Value and interpretation
General
When heated to decomposition it emits toxic gases of sulphur and nitrogen oxides
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
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Human health
