| (4-chlorophenoxy)acetic acid |
 |
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SUMMARY
4-CPA is a plant growth regulator that does not have approval for use in the EU. It is highly soluble in water and is quite volatile. Little is known about its persistence in soil and aquatic systems. It is moderately toxic to mammals and has a high potential for bioaccumulation. It is also a recognised irritant. It is moderately toxic to birds, honeybees and most aquatic organisms. However, it has a relatively low toxicity to fish. GENERAL INFORMATION 
for (4-chlorophenoxy)acetic acid
Description: A plant growth regulator used fruit setting and thining
Example pests controlled: Growth - in terms of thinging and fruit set
Example applications: Tomatoes; Grapes
Efficacy & activity: -
Availability status: Current
Introduction & key dates: Current
EC Regulation 1107/2009 (repealing 91/414):
| Status | Not approved |
| Dossier rapporteur/co-rapporteur | Not applicable |
| Date inclusion expires | Expired |
| EU Candidate for substitution (CfS) | Not applicable |
| Listed in EU database | Yes |
Approved for use (
) or known to be used (
) in the following European countries: 
AT |
BE |
BG |
CY |
CZ |
DE |
DK |
EE |
EL |
ES |
FI |
FR |
HR |
HU |
IE |
IT |
LT |
LU |
LV |
MT |
NL |
PL |
PT |
RO |
SE |
SI |
SK |
UK |
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Chemical structure:
| Isomerism | None |
| Chemical formula | C8H7ClO3 |
| Canonical SMILES | C1=CC(=CC=C1OCC(=O)O)Cl |
| Isomeric SMILES | No data |
| International Chemical Identifier key (InChIKey) | SODPIMGUZLOIPE-UHFFFAOYSA-N |
| International Chemical Identifier (InChI) | InChI=1S/C8H7ClO3/c9-6-1-3-7(4-2-6)12-5-8(10)11/h1-4H,5H2,(H,10,11) |
| 2D structure diagram/image available? | Yes |
General status:
| Pesticide type | Plant growth regulator, Herbicide | |||
| Substance group | Auxin | |||
| Minimum active substance purity | - | |||
| Known relevant impurities | - | |||
| Substance origin | Synthetic | |||
| Mode of action | Auxin-transport inhibitor. Absorbed by tissue and translocated to roots | |||
| CAS RN | 122-88-3 | |||
| EC number | 204-581-3 | |||
| CIPAC number | 291 | |||
| US EPA chemical code | 019401 | |||
| PubChem CID | 26229 | |||
| Molecular mass (g mol-1) | 186.59 | |||
| PIN (Preferred Identification Name) | (4-chlorophenoxy)acetic acid | |||
| IUPAC name | 4-chlorophenoxyacetic acid | |||
| CAS name | (4-chlorophenoxy)acetic acid | |||
| Other status information | - | |||
| Relevant Environmental Water Quality Standards | - | |||
| Herbicide Resistance Classification (HRAC) | Not known | |||
| Herbicide Resistance Classification (WSSA) | - | |||
| Insecticide Resistance Classification (IRAC) | Not applicable | |||
| Fungicide Resistance Classification (FRAC) | Not applicable | |||
| Examples of recorded resistance | - | |||
| Physical state | Off-white crystalline solid | |||
| Related substances & organisms | - | |||
Formulations:
| Property |
Value | |||
| Example manufacturers & suppliers of products using this active now or historically |
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| Example products using this active |
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| UK LERAP status | No UK approval for use as a pesticide under EC Regulation 1107/2009 | |||
| Formulation and application details | Available in a range of formulations including aerosols, liquids and tablets. | |||
ENVIRONMENTAL FATE
for (4-chlorophenoxy)acetic acid
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 957 | CA3 | High | |
| Solubility - In organic solvents at 20oC (mg l-1) | - | - | - | |
| Melting point (oC) | 157 | CA3 | - | |
| Boiling point (oC) | Decomposes before boiling | V3 | - | |
| Degradation point (oC) | - | - | - | |
| Flashpoint (oC) | Not expected to self ignite; Not highly flammable | V3 | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 1.78 X 1002 | Calculated | - |
| Log P | 2.25 | CA3 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.52 | L3 | - | |
| Dissociation constant (pKa) at 25oC | 3.01 | DW4 | - | |
| Note: Weak acid | ||||
| Vapour pressure at 20oC (mPa) | 2.40 X 10-02 | L3 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 6.48 X 10-08 | CA3 | Non-volatile | |
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 | - | - | - |
| Note | - | |||
| Potential for particle bound transport index |
- | - | - | |
| Maximum UV-vis absorption L mol-1 cm-1 | - | - | - | |
| Surface tension (mN m-1) | - | - | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | - | - | - |
| DT50 (lab at 20oC) | - | - | - | |
| DT50 (field) | - | - | - | |
| DT90 (lab at 20oC) | - | - | - | |
| 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 20oC and pH 7 | Value | - | - | - |
| Note | - | |||
| Water-sediment DT50 (days) | - | - | - | |
| Water phase only DT50 (days) | - | - | - | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | CA2 | Mobile |
| Koc | 18 | |||
| Notes and range | Estimated | |||
| Freundlich | Kf | - | - | - |
| Kfoc | - | |||
| 1/n | - | |||
| Notes and range | - | |||
| pH sensitivity | - | |||
Other known metabolites:
| Metabolite name and reference | Aliases | Formation medium / Rate | Estimated maximum occurrence fraction | Metabolising enzymes |
| centrophenoxine | - | Plant | - | - |
ECOTOXICOLOGY
for (4-chlorophenoxy)acetic acid
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | Low risk | Q3 Based on LogP < 3 | Low potential |
| CT50 (days) | - | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | 850 | C4 Rat | Moderate | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | - | - |
| (ppm diet) | - | - | ||
| Birds - Acute LD50 (mg kg-1) | - | - | - | |
| Birds - Short term dietary (LC50/LD50) | - | - | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | > 180 | CA3 Lepomis macrochirus | Low | |
| Fish - Chronic 21 day NOEC (mg l-1) | - | - | - | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | > 40 | Q2 Daphnia magna | Moderate | |
| 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) | 1.4 | Q2 Unknown species | Moderate | |
| Algae - Chronic 96 hour NOEC, growth (mg l-1) | 1 | A2 Unknown species | Moderate | |
| Honeybees (Apis spp.) | Contact acute LD50 (worst case from 24 , 48 and 72 hour values - μg bee-1) | > 100 | E3 | Low |
| 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 14 day NOEC, reproduction (mg kg-1) | - | - | - | |
| Other soil macro-organisms - e.g. Collembola | LR50 / EC50 / NOEC / % Effect | - | - | - |
| 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
for (4-chlorophenoxy)acetic acid
General:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Threshold of Toxicological Concern (Cramer Class) |
High (class III) | - | - | |
| Mammals - Acute oral LD50 (mg kg-1) | 850 | C4 Rat | Moderate | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 2200 | L3 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | 10.6 | L3 Rat | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | - | - | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | - | - | - | |
| AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) | - | - | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | - | - | - | |
| Dermal penetration studies (%) | - | - | - | |
| Dangerous Substances Directive 76/464 | - | - | - | |
| Exposure Routes | Public | Exposure from air or water very low as it is usually used inside Small risk of dietary exposure Source: US EPA |
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| Occupational | Low risk of exposure during handling Source: US EPA |
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| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water Standards | - | - | - | |
| Drinking Water MAC (μg l-1) | - | - | - | |
Health issues:
| Carcinogen | Genotoxic | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
|
A0; B0; C0; D0; E0 | - |
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
- |
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- |
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| General human health issues | Potential irritant Potential kidney toxicant |
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| Key: Genotoxicity A: Chromosome aberration (EFSA database) B: DNA damage/repair (EFSA database) C: Gene mutation (EFSA database) D: Genome mutation (EFSA database) E: Unspecified genotoxicity type (miscellaneous data source) 0: No data 1: Positive 2: Mixed/ambiguous results 3: Negative |
Key: Other : Yes, known to cause a problem  : No, known not to cause a problem  : Possibly, status not identified - : No data found |
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Handling issues:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| General |
IMDG Transport Code is usually 8 | |||
| CLP classification 2013 | Health: H302 | |||
| EC Risk Classification |
Xn - Harmful: R22 | |||
| EC Safety Classification |
S2 | |||
| WHO Classification | II | - | Moderately hazardous | |
| UN Number | Usually 3265 | |||
| Waste disposal & packaging |
Packaging Group III (minor danger) | |||
TRANSLATIONS
for (4-chlorophenoxy)acetic acid
| Language | Name |
| English | (4-chlorophenoxy)acetic acid |
| French | acide 4 chlorophenoxyacetique |
| German | 4-CPA |
| Danish | 4-CPA |
| Italian | 4-CPA (acido 4-clorofenossiacetico =PCPA) |
| Spanish | 4-CPA |
| Greek | - |
| Slovenian | 4-CPA |
| Polish | 4-CPA |
| Swedish | - |
| Hungarian | 4-CPA |
| Dutch | - |
Record last updated: Monday 28 May 2018
Contact: aeru@herts.ac.uk