Dehydroacetic acid	Last updated: 07/01/2021
(Also known as: DHA; methylacetopyronone)

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GENERAL INFORMATION

Description	An obsolete, unclassified fungicide
Example pests controlled	Mould
Example applications	Fresh produce
Efficacy & activity	-
Availability status	Obsolete
Introduction & key dates	1950, first reported

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	No
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	Dehydroacetic acid is a chiral molecule. Exists in three tautomeric forms.
Chemical formula	C₈H₈O₄
Canonical SMILES	CC1=CC(=C(C(=O)O1)C(=O)C)O
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	PKLPQOJFHFGVBS-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C8H8O4/c1-4-3-6(10)7(5(2)9)8(11)12-4/h3,10H,1-2H3
2D structure diagram/image available?	Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
dehydroacetic acid	-

General status

Pesticide type	Fungicide, Other substance
Other constituent type	Biocide, Preservative, food additive
Substance group	Unclassified
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	-
CAS RN	520-45-6
Alternative/old CAS RN	771-03-9; 16807-48-0
EC number	208-293-9
CIPAC number	-
US EPA chemical code	-
PubChem CID	122903
Molecular mass	168.15
PIN (Preferred Identification Name)	3-acetyl-2-hydroxy-6-methyl-4H-pyran-4-one
IUPAC name	2-acetyl-5-methyl-3-oxopent-4-en-5-olide
CAS name	3-acetyl-6-methyl-2H-pyran-2,4(3H)-dione (i)
Other status information	-
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 known
Examples of recorded resistance	-
Physical state	Off-white coloured powdery solid

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	-
Example products using this active	Dow Chemical Co
Formulation and application details	-

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		330000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	High
Solubility - In organic solvents at 20 °C (mg l⁻¹)		140000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Methanol	-
Melting point (°C)		109	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Sublimes	-
Boiling point (°C)		269	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		366	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source	-
Octanol-water partition coefficient at pH 7, 20 °C	P	-	-	-
	Log P	-	-	-
Bulk density (g ml⁻¹)		-	-	-
Dissociation constant pKa) at 25 °C		-	-	-
		-
Vapour pressure at 20 °C (mPa)		2.5 X 1005	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Highly volatile
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		-	-	-
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)	-	-	-
	DT₅₀ (lab at 20 °C)	-	-	-
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	-
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	-	-	-
	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	-	-	-
	Koc	-
	Notes and range	-
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		-	-	-
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	Cannot be calculated	-	-
	Note	-
Potential for particle bound transport index		-	-	-
Potential for loss via drain flow		-	-	-

ECOTOXICOLOGY

Property		Value	Source; quality score; and other information	Interpretation
Bio-concentration factor	BCF (l kg⁻¹)	93.0	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source (whole fish)	Low potential
	CT₅₀ (days)	30		-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		1000	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)	-	-	-
	(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)		-	-	-
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		-	-	-
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)		-	-	-
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		-	-	-
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)		1000	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)		-	-	-
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		-	-	-
Exposure Routes	Public	-
	Occupational	-
European MRLs		EU MRL pesticide database
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l⁻¹)		-	-	-

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 No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant No data found No data found ✓Yes, known to cause a problem Respiratory tract irritant Skin irritant Skin sensitiser ✓Yes, known to cause a problem ✓Yes, known to cause a problem ✓Yes, known to cause a problem Eye irritant Phototoxicant   ✓Yes, known to cause a problem No data found
General human health issues		Toxic is swallowed Possible kidney, liver and central nervous system toxicant

Handling issues

Property	Value and interpretation
General	Not compatible with strong oxidising or reducing agents May emit irritating vapours if heated
CLP classification 2013	-
EC Risk Classification	Xn - Harmful: R22
EC Safety Classification	-
WHO Classification	III (Slightly hazardous)
UN Number	-
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	dehydroacetic acid
French	acide dehydroacetique
German	-
Danish	-
Italian	-
Spanish	-
Greek	-
Polish	-
Swedish	-
Hungarian	-
Dutch	-

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Record last updated:	07/01/2021
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