(Also known as: alpha-HCH; alpha-benzenehexachloride; alpha-BHC; alpha-lindane)
SUMMARY
Alpha-hexachlorocyclohexane is an insecticide that is not generally approved for use in the developed world. It is moderately toxic to mammals and is likely to be carcinogenic. Alpha-hexachlorocyclohexane has a low aqueous solubility and is highly volatile. It is moderately persistent is soil and slightly mobile. It is moderately toxic to birds and aquatic organisms.
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 High alert: Potential for particle bound transport: High
Human health Moderate alert: Mammals acute toxicity: Moderate; Possible Carcinogen; Neurotoxicant
GENERAL INFORMATION
Description
Historically an insecticide and a component of the mixed isomer product but now only produced as a byproduct of lindane production. It is also a lindane impurity that has some insecticidal properties
Example pests controlled
Soil-dwelling and plant eating insects
Example applications
Fruit and vegetable crops; Forestry; Public health applications
Efficacy & activity
-
Availability status
-
Introduction & key dates
-
GB regulatory status
GB COPR regulatory status
Not approved
Date COPR inclusion expires
Not applicable
GB LERAP status
No UK approval for use as a plant protection agent
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Not applicable
EU Candidate for substitution (CfS)
Not applicable
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
ISIceland
NONorway
Additional information
Also used in
-
Chemical structure
Isomerism
There are nine stereoisomers of HCH (eight diastereomers, one of which has two enantiomers).
Example manufacturers & suppliers of products using this active now or historically
-
Example products using this active
-
Formulation and application details
-
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
2.0
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
18000
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Ether
-
Melting point (°C)
159
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
-
Boiling point (°C)
288
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
-
Degradation point (°C)
-
-
-
Flashpoint (°C)
-
-
-
Octanol-water partition coefficient at pH 7, 20 °C
P
6.61 X 1003
Calculated
-
Log P
3.82
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
High
Fat solubility of residues
Solubility
Likely to be soluble
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
-
Data type
Based on chemical group
Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source
-
Density (g ml⁻¹)
1.87
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
-
-
-
-
Vapour pressure at 20 °C (mPa)
5.99
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
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)
-
-
-
Volatilisation as max % of applied dose lost
From plant surface
-
-
-
From soil surface
-
-
-
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
No absorption > 290nm
E3 E = Manufacturers safety data sheets 3 = Unverified data of known source
-
Surface tension (mN m⁻¹)
-
-
-
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
175
R3 R = Peer reviewed scientific publications 3 = Unverified data of known source
Persistent
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
DT₅₀ sandy loam 55 days in subtropical conditions (R2), temperate climate data suggests 150-200 days (R3)
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
Not thought to be a major degradation route
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)
-
R3 R = Peer reviewed scientific publications 3 = Unverified data of known source
Slightly mobile
Koc (mL g⁻¹)
1888
Notes and range
Literature gives Koc range 1780-1995 mL g⁻¹
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
1.62
Calculated
Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
4.93 X 10-02
Calculated
-
Note
-
Potential for particle bound transport index
High
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)
-
-
-
CT₅₀ (days)
-
-
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
pentachlorocyclohexane
-
-
-
tetrachlorobenzene
-
-
-
trichlorobenzene
-
-
-
dichlorobenzene
-
-
-
Known groundwater metabolites
None
Other known metabolites
None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
177
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Rat
Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
-
-
(ppm diet)
-
-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Birds - Acute LD₅₀ (mg kg⁻¹)
-
-
-
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)
-
-
-
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)
-
-
-
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)
1.05
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 48 hr EC₅₀
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
-
-
-
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
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
?Possibly, status not identified
Respiratory tract irritant
Skin irritant
Skin sensitiser
?Possibly, status not identified
?Possibly, status not identified
No data found
Eye irritant
Phototoxicant
?Possibly, status not identified
No data found
General human health issues
Exposure may cause dyspnoea, anorexia, tremors, convulsions and cramps Liver, kidney and heart toxicant Induces a carcinogenic response in rodents via aberrant cell proliferation; CLP data - suspected carcinogen; US NTP - suspected carcinogen; OSHA - anticipated 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
Warning:
Ecotoxicity
