| dimethachlor (Ref: CGA 17020) |
 |
Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
GENERAL INFORMATION 
for dimethachlor
Description: A herbicide used pre-emergence to control most annual grasses and broad-leaved weeds
Example pests controlled: Loose silky-bent; Meadow grass; Brome; Slender foxtail; Common chickweed; Red dead-nettle; Mayweed
Example applications: Winter oilseed rape; Soybeans; Sugarbeet
Efficacy & activity: -
Availability status: Current
Introduction & key dates: 1977
EC Regulation 1107/2009 (repealing 91/414):
| Status | Approved |
| Dossier rapporteur/co-rapporteur | Hungary/Austria |
| Date inclusion expires | 31/12/2021 |
| EU Candidate for substitution (CfS) | No |
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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General status:
| Pesticide type | Herbicide | |||
| Substance group | Chloroacetamide | |||
| Minimum active substance purity | - | |||
| Known relevant impurities | - | |||
| Substance origin | Synthetic | |||
| Mode of action | Selective, absorbed by new shoots of seedlings and roots. Inhibition of VLCFA (inhibition of cell division) | |||
| CAS RN | 50563-36-5 | |||
| EC number | 256-625-6 | |||
| CIPAC number | 688 | |||
| US EPA chemical code | - | |||
| Isomerism | - | |||
| Chemical formula | C13H18ClNO2 | |||
| SMILES | ClCC(=O)N(c1c(cccc1C)C)CCOC | |||
| International Chemical Identifier key (InChIKey) | SCCDDNKJYDZXMM-UHFFFAOYSA-N | |||
| International Chemical Identifier (InChI) | InChI=1S/C13H18ClNO2/c1-10-5-4-6-11(2)13(10)15(7-8-17-3)12(16)9-14/h4-6H,7-9H2,1-3H3 | |||
| Structure diagram/image available? | Yes | |||
| Molecular mass (g mol-1) | 255.74 | |||
| PIN (Preferred Identification Name) | 2-chloro-N-(2,6-dimethylphenyl)-N-(2-methoxyethyl)acetamide | |||
| IUPAC name | 2-chloro-N-(2-methoxyethyl)acet-2',6'-xylidide | |||
| CAS name | 2-chloro-N-(2,6-dimethylphenyl)-N-(2-methoxyethyl)acetamide | |||
| Other status information | - | |||
| Herbicide Resistance Classification (HRAC) | K3 | |||
| Herbicide Resistance Classification (WSSA) | 15 | |||
| Insecticide Resistance Classification (IRAC) | Not applicable | |||
| Fungicide Resistance Classification (FRAC) | Not applicable | |||
| Examples of recorded resistance | - | |||
| Physical state | Colourless crystals | |||
| 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 or outside scope | |||
| Formulation and application details | Usually supplied as an emulsifiable concentrate. | |||
ENVIRONMENTAL FATE
for dimethachlor
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 2300 | A5 | High | |
| Solubility - In organic solvents at 20oC (mg l-1) | 500000 | A5 - Methanol | - | |
| 500000 | A5 - Acetone | - | ||
| 42000 | A5 - Hexane | - | ||
| 440000 | A5 - Octanol | - | ||
| Melting point (oC) | 46.3 | A5 | - | |
| Boiling point (oC) | Decomposes before boiling | A4 | - | |
| Degradation point (oC) | 300 | A4 | - | |
| Flashpoint (oC) | Not expected to self ignite; Not highly flammable | A5 | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 1.48 X 1002 | Calculated | - |
| Log P | 2.17 | A5 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.23 | L3 | - | |
| Dissociation constant (pKa) at 25oC | Not applicable | A5 | - | |
| Note: No dissociation | ||||
| Vapour pressure at 25oC (mPa) | 0.64 | A5 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 1.70 X 10-04 | A5 | Non-volatile | |
GUS leaching potential index  |
1.76 | Calculated | Low leachability | |
| SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate |
Value | 8.68 X 10-03 | Calculated | - |
| Note | - | |||
| Potential for particle bound transport index |
- | Calculated | Low | |
| Maximum UV-vis absorption L mol-1 cm-1 | Neutral solution: 215nm = 14461, 265nm = 486; [Acidic solution: 215nm = 14768, 265nm = 572; [Basic solution: 215nm = 9576, 265nm = 469 | A5 | - | |
| Surface tension (mN m-1) | 57.2-66.1 | A4 at 20oC, 0.19-1.9 g l-1 | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | 7 | A5 | Non-persistent |
| DT50 (lab at 20oC) | 6.5 | A5 | Non-persistent | |
| DT50 (field) | 3.2 | A5 | Non-persistent | |
| DT90 (lab at 20oC) | 27.8 | A5 | - | |
| DT90 (field) | 10.5 | A5 | - | |
| DT50 modelling endpoint | - | - | - | |
| Note | EU dossier lab studies DT50 range 2.3 (silt loam) - 15.6 (loamy sand) days, DT90 range 11-65.9 days | |||
| 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 | Stable | A5 | - |
| Note | - | |||
| Aqueous hydrolysis DT50 (days) at 20oC and pH 7 | Value | 200 | A5 | Persistent |
| Note | Stable pH 1 to pH 9, DT50 9.3 days at pH 13 up to 50 degC | |||
| Water-sediment DT50 (days) | 14.1 | A5 | Fast | |
| Water phase only DT50 (days) | 10 | A5 | Moderately fast | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | - | - |
| Koc | - | |||
| Notes and range | - | |||
| Freundlich | Kf | 4.20 | A5 | Mobile |
| Kfoc | 69 | |||
| 1/n | 0.91 | |||
| Notes and range | EU dossier kf range 0.32-18.4, Kfoc range 29.7-128 mL/g, 1/n range 0.760-0.939, Soils=10 | |||
| pH sensitivity | No | |||
Key metabolites:
| Metabolite | Formation medium | Estimated maximum occurrence fraction | 1107/2009 relevancy |
|
| N-(2,6-dimethylphenyl)-N-(2-methoxyethyl)oxalamic acid (Ref: CGA 50266) |
Soil | 0.355 | Major fraction, Relevant | |
| ((2,6-dimethylphenyl)-2-methoxyethyl)carbamoyl)methanesulfonic acid sodium salt (Ref: CGA 354742) |
Soil | 0.158 | Major fraction, Relevant | |
Other known metabolites:
| Metabolite name and reference | Aliases | Formation medium / Rate | Estimated maximum occurrence fraction | Metabolising enzymes |
| IMPURITY | - | - | - | - |
| N-carboxymethyl-N-(2,6-dimethyl-phenyl)oxalamic acid (Ref: CGA 102935) Note: Risk to groundwater |
- | Soil (Aerobic) | - | - |
| (2,6-dimethylphenylcarbamoyl)-methanesulfonic acid sodium salt (Ref: CGA 369873) Note: Detected in lysimeter leachate; Risk to groundwater |
- | Soil (Aerobic); Groundwater | - | - |
| [(2,6-dimethylphenyl)-(2-sulfo-acetyl)amino]acetic acid sodium salt (Ref: CGA 373464) Note: Detected in lysimeter leachate; Risk to groundwater |
- | Soil (Aerobic) | - | - |
| N-(2,6-dimethylphenyl)-N-(2-methoxyethyl)acetamide (Ref: CGA 42443) |
- | Soil (Anaerobic); Water/sediment | - | - |
| 2,6-dimethylaniline (Ref: CGA 72649) |
- | Not applicable | - | - |
| 3-{2-[(2,6-dimethyl-phenyl)-(2-hy-droxyacetyl)amino]ethylsulfanyl}-2-hydroxypropionic acid (Ref: SYN 528702) Note: Risk to groundwater |
- | Soil (Aerobic) | - | - |
| 2-[(2-hydroxyacetyl)-(2-methoxy-ethyl)amino]-3-methylbenzoic acid (Ref: SYN 530561) Note: Detected in lysimeter leachate; Risk to groundwater |
- | Soil (Aerobic) | - | - |
ECOTOXICOLOGY
for dimethachlor
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | 75 | Q2 Estimated | Low potential |
| CT50 (days) | Not available | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | 1600 | A5 Rat | Moderate | |
| Mammals - Short term dietary NOEL | (mg kg-1) | > 12 | L2 Rat, 2 year | High |
| (ppm diet) | > 300 | - | ||
| Birds - Acute LD50 (mg kg-1) | 524 | A5 Coturnix japonica | Moderate | |
| Birds - Short term dietary (LC50/LD50) | > 1470 mg kg bw-1 day-1 | A5 Coturnix japonica | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | 3.9 | A5 Oncorhynchus mykiss | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | 0.85 | A5 Oncorhynchus mykiss | Moderate | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | 24 | A5 Daphnia magna | Moderate | |
| Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) | 2.3 | A5 Daphnia magna | 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) | 4.0 | A5 Chironomus riparius | Moderate | |
| Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) | 25.0 | A5 Chironomus riparius | Moderate | |
| Aquatic plants - Acute 7 day EC50, biomass (mg l-1) | 0.035 | A5 Lemna gibba | Moderate | |
| Non-target plants | > 1500 | A5 Echinochloa crusgalli Vegetative vigour, ER50 as g/ha |
- | |
| > 1500 | A5 Echinochloa crusgalli Seedling emergence, ER50 as g/ha |
- | ||
| Algae - Acute 72 hour EC50, growth (mg l-1) | 0.0065 | A5 Pseudokirchneriella subcapitata | High | |
| Algae - Chronic 96 hour NOEC, growth (mg l-1) | - | - | - | |
| Honeybees | Contact acute 48 hour LD50 (μg bee-1) | > 200 | A5 | Low |
| Oral acute 48 hour LD50 (μg bee-1) | > 300 | A5 | Low | |
| Unknown mode acute 48 hour LD50 (μg bee-1) | - | - | - | |
| Earthworms - Acute 14 day LC50 (mg kg-1) | 70 | A5 Eisenia foetida corr | Moderate | |
| 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 | 91 | 48 hour A5 Aphidius rhopalosiphi, adult |
- |
| % Effect | - | - | - | |
| Other arthropod (2) | LR50 g ha-1 | 655 | 7 day A5 Typhlodromus pyri |
- |
| % Effect | - | - | - | |
| Soil micro-organisms | Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect |
A5 Dose: 7.5 kg ha-1, 28 days |
- | |
| Mesocosm study data | NOEAEC mg l-1 | - | - | - |
| NOEAEC mg l-1 | - | - | - | |
HUMAN HEALTH AND PROTECTION
for dimethachlor
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) | 1600 | A5 Rat | Moderate | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 2000 | A5 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | > 4.45 | A5 Rat, 4 hr (nose only) | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | 0.1 | A5 Rat, SF=100 | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | 0.5 | A5 Rat, SF=100 | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | 0.1 | A5 Dog, SF=100 | - | |
| Dermal penetration studies (%) | 3.0-10.0 | A5 concentration dependent | - | |
| Dangerous Substances Directive 76/464 | - | - | - | |
| Exposure Limits | - | - | - | |
| Exposure Routes | Public | No unacceptable risks to bystanders identified | ||
| Occupational | No unacceptable risks to operators or other workers identified | |||
| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water MAC (μg l-1) | 0.1 | EU Dir 89/778/EC limit; A5 | - | |
Health issues:
| Carcinogen | Mutagen | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
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| General human health issues | No further information available | |||||||
: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found
Handling issues:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| General |
Not explosive or oxidising IMDG Transport Code is usually 9 |
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| CLP classification 2013 | Health: H302, H317 Environment: H400, H410 |
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| EC Risk Classification |
Xn - Harmful: R22, R43 N - Dangerous for the environment: R50, R53 |
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| EC Safety Classification |
S2, S24, S37, S60, S61 | |||
| WHO Classification | II | - | Moderately hazardous | |
| US EPA Classification (formulation) | No consensus across products or no products available | - | - | |
| UN Number | Usualy 3077 | |||
| Waste disposal & packaging |
Packaging Group III (minor danger) | |||
| Language | Name |
| English | dimethachlor |
| French | dimethachlore |
| German | Dimethachlor |
| Danish | dimethachlor |
| Italian | dimetaclor |
| Spanish | dimetacloro |
| Greek | dimethachlor |
| Slovenian | dimetaklor |
| Polish | dimetachlor |
| Swedish | - |
| Hungarian | dimetaklor |
| Dutch | - |
Record last updated: Thursday 04 January 2018
Contact: aeru@herts.ac.uk