Alpha-hexachlorocyclohexane (Ref: ENT 9232)	Last updated: 16/12/2020
(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 considered 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 organisims.

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	Unknown
Introduction & key dates	-

UK regulatory status

UK COPR regulatory status	Not approved
Date COPR inclusion expires	Not applicable
UK LERAP status	No UK approval for use

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

Also used in

Also used in	-

Chemical structure

Isomerism	There are nine stereoisomers (eight diastereomers, one of which has two enantiomers).
Chemical formula	C₆H₆Cl₆
Canonical SMILES	-
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	JLYXXMFPNIAWKQ-LKPKBOIGSA-N
International Chemical Identifier (InChI)	InChI=1S/C6H6Cl6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h1-6H/t1-,2-,3-,4-,5+,6+/m0/s1
2D structure diagram/image available?	Yes

General status

Pesticide type	Insecticide, Other substance
Other constituent type	Impurity
Substance group	Organochlorine
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Not applicable
CAS RN	319-84-6
EC number	206-270-8
CIPAC number	-
US EPA chemical code	-
PubChem CID	727
Molecular mass	290.83
PIN (Preferred Identification Name)	-
IUPAC name	-
CAS name	α-hexachlorocyclohexane
Other status information	POP; Water pollutant; Marine pollutant; Pan Bad Actor Chemical; PIC; Possible groundwater pollutant
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	Not applicable
Herbicide Resistance Classification (WSSA)	Not applicable
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	-
Physical state	White to beige coloured crystalline powder
Related substances & organisms	lindane

Formulations

Property	Value
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 / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		18000	CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 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
Bulk 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
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		-	-	-
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 on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL₅₀ 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)		-	-	-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source	Slightly mobile
	Koc	1888
	Notes and range	Literature gives Koc range 1780-1995 mL g⁻¹
Freundlich	Kf	-	-	-
	Kfoc	-
	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	-

Other known metabolites

Metabolite name and reference	Aliases	Formation medium / Rate	Estimated maximum occurrence fraction	Metabolising enzymes
pentachlorocyclohexane	-	Soil (Aerobic)	-	-
tetrachlorobenzene	-	Soil (Aerobic)	-	-
trichlorobenzene	-	Soil (Aerobic)	-	-
dichlorobenzene	-	Soil (Aerobic)	-	-

ECOTOXICOLOGY

Property		Value	Source; quality score; and other information	Interpretation
Bio-concentration factor	BCF (l kg⁻¹)	-	-	-
	CT₅₀ (days)	-		-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		177	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 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)		-	-	-
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		> 0.820	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Danio rerio	Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		0.370	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Daphnia magna	Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		0.1	P2 P = Other governments and regulators 2 = Unverified data of unknown source Daphnia magna 25 day EC₅₀	Moderate
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)		-	-	-
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		> 10	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Chlorella pyrenoidosa	Low
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		-	-	-
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)	-	-	-
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 pollinators (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other pollinators (2)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		-	-	-
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)		-	-	-
Other soil macro-organisms	Acute LC₅₀ (mg kg⁻¹)	-	-	-
	Chronic NOEC (mg kg⁻¹)	-	-	-
Other arthropod (1)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	-	-	-
Other arthropod (2)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	-	-	-
Soil micro-organisms		-	-	-
Mesocosm study data	NOEAEC mg l⁻¹	-	-	-
	NOEAEC mg l⁻¹	-	-	-

HUMAN HEALTH AND PROTECTION

General

Property		Value	Source; quality score; and other information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		177	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source Rat	Moderate
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)		-	-	-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)		-	-	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)		-	-	-
Dermal penetration studies (%)		-	-	-
Dangerous Substances Directive 76/464		List I	-	-
Exposure Routes	Public	May be absorbed through the skin
	Occupational	May be absorbed through the skin
MRLs	European	EU MRL pesticide database
	Notes	-
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l⁻¹)		-	-	-

Health issues

Specific human health issues		Carcinogen Genotoxic Endocrine disruptor ✓Yes, known 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 ?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

Handling issues

Property	Value and interpretation
General	Flammable
CLP classification 2013	-
EC Risk Classification	Carcinogen category 3: R40 T - Toxic: R52, Xn - Harmful: R25 N - Dangerous for the environment: R50/53
EC Safety Classification	S22, S36/37, S45, S60, S61
WHO Classification	NL (Not listed)
UN Number	1230
Waste disposal & packaging	Packaging Group II (medium danger)

TRANSLATIONS

Language	Name
English	alpha-hexachlorocyclohexane
French	-
German	alpha-Hexachlorocyclohexan
Danish	-
Italian	-
Spanish	-
Greek	-
Polish	-
Swedish	-
Hungarian	-
Dutch	-

---

Record last updated:	16/12/2020
Contact:	aeru@herts.ac.uk
Please cite as:	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