Endrin	Last updated: 16/01/2023
(Also known as: nendrin; OMS 197; aldrin epoxide; Experimental Insecticide 269)

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SUMMARY

Endrin is an obsolete, multi-use organochlorine insecticide. It has a low aqueous solubility and is non-volatile. Based on its chemical properties it is not expected to leach to groundwater. Endrin tends to be persistent in soil systems. It is highly toxic to mammals and is a neurotoxin. It is also highly toxic to birds, honeybees and most aquatic organisms but slightly less so to 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 High alert: Potential for particle bound transport: High Warning: Significant data are missing	Ecotoxicity High alert: Birds acute ecotoxicity: High; Fish acute ecotoxicity: High; Fish chronic ecotoxicity: High; Daphnia acute ecotoxicity: High; Bees acute contact ecotoxicity: High	Human health High alert: Mammals acute toxicity: High; Endocrine distrupter; Neurotoxicant

GENERAL INFORMATION

Description	A multi-use but now obsolete pesticide used to control insects, rodents, and birds.
Example pests controlled	Aphids; Lygus bugs; Grasshoppers; Small mammals including mice, voles
Example applications	Field crops; Cotton; Grains; Rice; Sugarcane
Efficacy & activity	-
Availability status	Considered obsolete but may be available in some countries; Banned in many countries
Introduction & key dates	1950s

UK regulatory status

UK COPR regulatory status	Not approved
Date COPR inclusion expires	Expired
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	-
Date EC 1107/2009 inclusion expires	Expired
EU Candidate for substitution (CfS)	-
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

Additional information

Also used in	-

Chemical structure

Isomerism	Isomeric
Chemical formula	C₁₂H₈Cl₆O
Canonical SMILES	C1C2C3C(C1C4C2O4)C5(C(=C(C3(C5(Cl)Cl)Cl)Cl)Cl)Cl
Isomeric SMILES	C1[C@@H]2[C@@H]3[C@H]([C@H]1[C@H]4[C@@H]2O4)[C@@]5(C(=C([C@]3(C5(Cl)Cl)Cl)Cl)Cl)Cl
International Chemical Identifier key (InChIKey)	DFBKLUNHFCTMDC-GKRDHZSOSA-N
International Chemical Identifier (InChI)	InChI=1S/C12H8Cl6O/c13-8-9(14)11(16)5-3-1-2(6-7(3)19-6)4(5)10(8,15)12(11,17)18/h2-7H,1H2/t2-,3-,4?,5?,6?,7?,10-,11-/m0/s1
2D structure diagram/image available?	Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
endrin	Unstated isomer

General status

Pesticide type	Insecticide, Avicide, Rodenticide
Substance groups	Organochloride insecticide; Cyclodiene insecticide
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Broad-spectrum, with contact and stomach action. Is a chloride channel-blocking agent.
CAS RN	72-20-8
EC number	200-775-7
CIPAC number	28
US EPA chemical code	041601
PubChem CID	12358480
CLP index number	602-051-00-X
Molecular mass	380.91
PIN (Preferred Identification Name)	(1aR,2R,2aR,3R,6S,6aS,7S,7aS)-3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphth[2,3-b]oxirene
IUPAC name	1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-exo-1,4-exo-5,8-dimethanonaphthalene
CAS name	(1aR,2R,2aR,3R,6S,6aS,7S,7aS)-rel-3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphth(2,3-b)oxirene
Other status information	WFD priority substance; POP - regulated by Stockholm Convention; LRTAP Annex I; PAN Dirty Dozen; OSPAR soc; Severe Marine Pollutant; Subject to the provisions of the UK Poisons Act 1972
Relevant Environmental Water Quality Standards	EU Directive 2008/105/EC EQS for the sum of all cyclodiene pesticides in: inland surface waters: 0.01 µg l⁻¹; Other surface waters; 0.005 µg l⁻¹ as annual average
Herbicide Resistance Classification (HRAC)	Not applicable
Herbicide Resistance Classification (WSSA)	Not applicable
Insecticide Resistance Classification (IRAC)	2A
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	Many recorded cases, Aphis gossypii, Culex pipiens pipiens, Empoasca biguttula, Leptocorisa oratorius, Spodoptera littoralis, many others
Physical state	White crystals

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Shell Chemical Company Velsicol
Example products using this active	Endrex Mendrin Nendrin Hexadrin
Formulation and application details	Available in a variety of formulations including wettable powders and emulsifiable concentrates

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		0.24	H4 H = The US ARS pesticide properties database (click here ) 4 = Verified data	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		-	-	-
Melting point (°C)		200	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source	-
Boiling point (°C)		-	-	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	1.58 X 1003	Calculated	-
	Log P	3.2	H4 H = The US ARS pesticide properties database (click here ) 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	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	-
Density (g ml⁻¹)		1.84	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source	-
Dissociation constant pKa) at 25 °C		-	-	-
		-
Vapour pressure at 20 °C (mPa)		2.0 X 10-07	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	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		1.48 X 10-01	H4 H = The US ARS pesticide properties database (click here ) 4 = Verified data	Moderately volatile
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)	4300	M4 M = GLEAMS Model database (Groundwater Loading Effects of Agricultural Management Systems) (click here ) 4 = Verified data	Very persistent
	DT₅₀ (lab at 20 °C)	-	-	-
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	Other sources: DT₅₀ up to 12 years (R3); FAO state DT₅₀ 4-14 days
Dissipation rate RL₅₀ on plant matrix	Value	3.3	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source	-
	Note	Birdsfoot trefoil leaves, n=1
Dissipation rate RL₅₀ on and in plant matrix	Value	4.0	R4 R = Peer reviewed scientific publications 4 = Verified data	-
	Note	Published literature RL₅₀ range 1.0-7.0 days, 2 field crops, various matrices, n=2
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)		-	-	-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	H3 H = The US ARS pesticide properties database (click here ) 3 = Unverified data of known source	Non-mobile
	Koc	10000
	Notes and range	Other sources: 31623 mL g⁻¹ (R3)
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		0.00	Calculated	Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	5.35 X 10-03	Calculated	-
	Note	Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW
Potential for particle bound transport index		High	Calculated	-
Potential for loss via drain flow		Non-mobile	Calculated	-
Bio-concentration factor	BCF (l kg⁻¹)	3970	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Whole body (Literature values log BCF range 2.2-3.4 ( R3 R = Peer reviewed scientific publications 3 = Unverified data of known source ))	Threshold for concern
	CT₅₀ (days)	Not available		-

Known soil metabolites

Metabolite	Major/Minor fraction	Estimated maximum occurrence fraction	Notes
endrin aldehyde	-	-	-

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)		> 7.5	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Rat	High
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)		5.6	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Anas platyrhynchos	High
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		> 66	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 Lumbricus terrestris	Moderate
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)	> 0.46	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	High
	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	-	-	-
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	-
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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		0.00073	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 Oncorhynchus mykiss	High
Fish - Chronic 21 day NOEC (mg l⁻¹)		0.00012	P3 P = Other governments and regulators 3 = Unverified data of known source Cyprinodon variegatus	High
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		0.0042	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	High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
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)		4.22	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Cironomus dilutus as 10d LC₅₀	Moderate
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		-	-	-
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		-	-	-
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)		> 7.5	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Rat	High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		5.0	R3 R = Peer reviewed scientific publications 3 = Unverified data of known source Rat	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		-	-	-
Other Mammal toxicity endpoints		-	-	-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)		0.0002	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)		-	-	-
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; List II	-	-
Exposure Routes	Public	-
	Occupational	-
MRLs	European	EU MRL pesticide database
	Great Britain	GB MRL Register
	Notes	-
Drinking Water Standards		Non-statutory WHO drinking water guideline 0.0006 mg l⁻¹	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes UK EA QS database 2018	-
Drinking Water MAC (μg l⁻¹)		-	-	-
Mammalian dose elimination route and rate		-	-	-

Health issues

Specific human health issues		Carcinogen Genotoxic Endocrine disruptor ?Possibly, status not identified 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 ✓Yes, known to cause a problem Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant ?Possibly, status not identified XNo, known not to cause a problem ✓Yes, known 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 No data found Eye irritant Phototoxicant   XNo, known not to cause a problem No data found
General human health issues		Highly toxic Endocrine issues - Competitive binding to androgen receptors

Handling issues

Property	Value and interpretation
General	No information available
CLP classification 2013	Health: H300, H311 Environment: H400, H410
WHO Classification	O (Obsolete substance)
UN Number	2761
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	endrin
French	endrine
German	Endrin
Danish	endrin
Italian	endrin
Spanish	endrin
Greek	endrin
Polish	endryna
Swedish	-
Hungarian	-
Dutch	endrine

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Record last updated:	16/01/2023
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