Dichlorprop (Ref: RD 406)	Last updated: 01/09/2023
(Also known as: 2,4-DP)

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SUMMARY

Dichlorprop is a post-emergence, selective herbicide. It has a moderate aqueous solubility and is volatile. Its data suggests it is not persistent in soils but may persist in some water systems. It is moderately toxic to. Dichlorprop has a moderate to low toxicity to most 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: Drainflow: Mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health Moderate alert: Mammals acute toxicity: Moderate; Reproduction/development effects Warning: Significant data are missing

GENERAL INFORMATION

Description	A herbicide for post-emergence control of annual and perennial broad-leaved weeds and some brush species
Example pests controlled	Canada thistle; Cocklebur; Ragweeds; Pigweed; Shepherd's purse; Stinkweed; Lambsquarter; Goosefoot; Wild mustard
Example applications	Cereals including wheat, barley; Non-crop situations including right-of-way, commercial and industrial sites
Efficacy & activity	-
Availability status	Current
Introduction & key dates	1961

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	Not applicable
Date EC 1107/2009 inclusion expires	Expired
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	Chiral with S- and R- enantiomers. Substance is racemic.
Chemical formula	C₉H₈Cl₂O₃
Canonical SMILES	CC(C(=O)O)OC1=C(C=C(C=C1)Cl)Cl
Isomeric SMILES	Clc1cc(Cl)ccc1OC(C(=O)O)C
International Chemical Identifier key (InChIKey)	MZHCENGPTKEIGP-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C9H8Cl2O3/c1-5(9(12)13)14-8-3-2-6(10)4-7(8)11/h2-5H,1H3,(H,12,13)
2D structure diagram/image available?	Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
dichlorprop	-

General status

Pesticide type	Herbicide, Plant Growth Regulator
Substance groups	Aryloxyalkanoic acid herbicide; Phenoxypropionic herbicde; Auxin PGR
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Selective, systemic, absorbed through leaves and translocates to roots. Synthetic auxin causing stem and leaf malformations leading to death.
CAS RN	120-36-5
Alternative/old CAS RN	7547-66-2
EC number	204-390-5
CIPAC number	84
US EPA chemical code	031401
PubChem CID	8427
CLP index number	607-045-00-0
Molecular mass	235.06
PIN (Preferred Identification Name)	rac-(2R)-2-(2,4-dichlorophenoxy)propanoic acid
IUPAC name	(RS)-2-(2,4-dichlorophenoxy)propionic acid
CAS name	2-(2,4-dichlorophenoxy)propanoic acid
Other status information	Potential groundwater contaminant
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Class (HRAC MoA class)	O
Herbicide Resistance Class (WSSA MoA class)	4
Insecticide Resistance Class (IRAC MoA class)	Not applicable
Fungicide Resistance Class (FRAC MOA class)	Not applicable
Examples of recorded resistance	-
Physical state	Colourless crystals
Related substances & organisms	dichlorprop-butotyl dichlorprop-dimethylammonium dichlorprop-etexyl dichlorprop-ethylammonium

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Headland Agrochemicals FBC Bayer Universal Crop Protection
Example products using this active	Weedone 170 Hedonal DP Hormatox Polyclene Seritox Polymore
Formulation and application details	Often supplied as an emulsifiable concentrate or as an emulsion.

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		350	H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data	Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)		689000	C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data Ethyl acetate	-
		1265000	C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data Acetone	-
		3030	C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data Hexane	-
		61200	C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data Toluene	-
Melting point (°C)		117	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)		204	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source (open cup)	-
Octanol-water partition coefficient at pH 7, 20 °C	P	1.95 X 1002	Calculated	-
	Log P	2.29	H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data	Low
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		1.42	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Dissociation constant pKa) at 25 °C		3	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
		Strong acid
Vapour pressure at 20 °C (mPa)		0.01	H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		8.80 X 10-06	H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data	Non-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)	10	W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available. 4 = Verified data	Non-persistent
	DT₅₀ (lab at 20 °C)	14	Y4 Y = Germany's Federal Environment Agency (UBA) (click here ) 4 = Verified data	Non-persistent
	DT₅₀ (field)	10	X3 X = WINPST database (click here ) 3 = Unverified data of known source	Non-persistent
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	Other sources: DT₅₀ 21-25 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	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	Stable	K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data	Stable
	Note	-
Water-sediment DT₅₀ (days)		12	K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data	Fast
Water phase only DT₅₀ (days)		-	-	-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	Q4 Q = Miscellaneous data from online sources 4 = Verified data	Mobile
	Koc	74
	Notes and range	Other sources: 12.0-170 mL g⁻¹ (R3)
Freundlich	Kf	0.77	R4 R = Peer reviewed scientific publications 4 = Verified data	Mobile
	Kfoc	41.2
	1/n	0.87
	Notes and range	Kf range 0.67-0.86 mL g⁻¹, Kfoc range 34.4-47.9 mL g⁻¹, 1/n range 0.86-0.88, Soils=2
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		2.39	Calculated	Transition state
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	5.07 X 10-02	Calculated	-
	Note	-
Potential for particle bound transport index		Low	Calculated	-
Potential for loss via drain flow		Mobile	Calculated	-
Bio-concentration factor	BCF (l kg⁻¹)	6	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source Estimated	Low potential
	CT₅₀ (days)	Not available		-

Known soil metabolites

Metabolite	Major/Minor fraction	Estimated maximum occurrence fraction	Notes
2,4-dichlorophenol	Minor fraction	-	-

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)		825	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	Moderate
Mammals - Short term dietary NOEL	(mg kg⁻¹)	-	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	-
	(ppm diet)	> 5		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		504	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Coturnix japonica	Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		1000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	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)	16	K4 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here ) 4 = Verified data	Moderate
	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 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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		> 0.5	J4 J = Pesticide Action Network database (click here ) 4 = Verified data Oncorhynchus mykiss	Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		> 100	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Daphnia magna	Low
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)		-	-	-
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		1100	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source Pseudokirchneriella subcapitata	Low
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		180	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source Unknown species	Low
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)		825	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		1400	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Mouse	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		0.65	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	-
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 II	-	-
Exposure Routes	Public	Low risk to Europeans as no longer approved for use
	Occupational	Low risk to Europeans as no longer approved for use
MRLs	European	EU MRL pesticide database
	Great Britain	GB MRL Register
	Notes	-
Drinking Water Standards		Non-statutory WHO drinking water guideline 0.1 mg l⁻¹	B5 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (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 No data found 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 No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant ?Possibly, status not identified No data found No data found Respiratory tract irritant Skin irritant Skin sensitiser No data found ✓Yes, known to cause a problem No data found Eye irritant Phototoxicant   ✓Yes, known to cause a problem No data found
General human health issues		No further information available

Handling issues

Property	Value and interpretation
General	No information available
CLP classification 2013	Health: H302, H312, H315, H318
WHO Classification	II (Moderately hazardous)
UN Number	-
Waste disposal & packaging	-
Shelf-life, storage, stability and reactivity	-

TRANSLATIONS

Language	Name
English	dichlorprop
French	dichlorprop
German	Dichlorprop
Danish	dichlorprop
Italian	diclorprop
Spanish	diclorprop
Greek	dichlorprop
Polish	dichlorprop
Swedish	-
Hungarian	dichlorprop
Dutch	dichloorprop
Norwegian	-

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Record last updated:	01/09/2023
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