| siduron |
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Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
SUMMARY
Siduron is a selective pre-emergence herbicide without EU regulatory approval for use. It has a low aqueous solubility, is volatile and, based on its chemical properties, it is moderately mobile with has a high potential to leach to groundwater. It is persistent in both soil and water systems. It has a relatively low mammalian toxicity and would not be expected to bioaccumulate. It is classified as an irritant. It is not highly toxic to birds, is moderately toxic to fish, algae and honey bees. GENERAL INFORMATION 
for siduron
Description: A pre-emergence herbicide used to control Digitaria spp. and other grass weeds used mainly for non-agricultural applications
Example pests controlled: Crabgrass; Downy brome; Foxtail; bentgrass; Fescue; Ryegrass; Canarygrass
Example applications: Golf courses; Sports fields; Sod farms and grass seed production; Roadsides; Parks
Efficacy & activity: -
Availability status: Current
Introduction & key dates: 1994
EC Regulation 1107/2009 (repealing 91/414):
| Status | Not approved |
| Dossier rapporteur/co-rapporteur | Not applicable |
| Date inclusion expires | Not applicable |
| EU Candidate for substitution (CfS) | - |
| 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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Also used in: Australia
Chemical structure:
| Isomerism | A chiral molecule. The technical material is an isomeric mixture of the cis-and trans-isomers. |
| Chemical formula | C14H20N2O |
| Canonical SMILES | CC1CCCCC1NC(=O)NC2=CC=CC=C2 |
| Isomeric SMILES | No data |
| International Chemical Identifier key (InChIKey) | JXVIIQLNUPXOII-UHFFFAOYSA-N |
| International Chemical Identifier (InChI) | InChI=1S/C14H20N2O/c1-11-7-5-6-10-13(11)16-14(17)15-12-8-3-2-4-9-12/h2-4,8-9,11,13H,5-7,10H2,1H3,(H2,15,16,17) |
| 2D structure diagram/image available? | Yes |
General status:
| Pesticide type | Herbicide | |||
| Substance group | Phenylurea | |||
| Minimum active substance purity | - | |||
| Known relevant impurities | - | |||
| Substance origin | Synthetic | |||
| Mode of action | Selective, absorbed by roots and translocated. Photosynthetic electron transport inhibitor at the photosystem II. | |||
| CAS RN | 1982-49-6 | |||
| EC number | 217-844-2 | |||
| CIPAC number | 321 | |||
| US EPA chemical code | 035509 | |||
| PubChem CID | 16116 | |||
| Molecular mass (g mol-1) | 232.32 | |||
| PIN (Preferred Identification Name) | N-(2-methylcyclohexyl)-N'-phenylurea | |||
| IUPAC name | 1-(2-methylcyclohexyl)-3-phenylurea | |||
| CAS name | N-(2-methylcyclohexyl)-N'-phenylurea | |||
| Other status information | - | |||
| Relevant Environmental Water Quality Standards | - | |||
| Herbicide Resistance Classification (HRAC) | C2 | |||
| Herbicide Resistance Classification (WSSA) | 7 | |||
| Insecticide Resistance Classification (IRAC) | Not applicable | |||
| Fungicide Resistance Classification (FRAC) | Not applicable | |||
| Examples of recorded resistance | - | |||
| Physical state | Colourless, odourless 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 as a pesticide under EC Regulation 1107/2009 | |||
| Formulation and application details | Usually formulated as a wettable powder and applied as a pre-emergence treatment to bare soil. It may also be formulated as a mixture with fertilisers. | |||
ENVIRONMENTAL FATE
for siduron
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 22.3 | H4 - 4 | Low | |
| Solubility - In organic solvents at 20oC (mg l-1) | - | - | - | |
| Melting point (oC) | 136 | F4 | - | |
| Boiling point (oC) | - | - | - | |
| Degradation point (oC) | - | - | - | |
| Flashpoint (oC) | - | - | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 2.70 X 1000 | Calculated | - |
| Log P | 0.431 | F4 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.08 | F4 | - | |
| Dissociation constant (pKa) at 25oC | Not applicable | F4 | - | |
| Note: No dissociation | ||||
| Vapour pressure at 20oC (mPa) | 5.30 X 10-04 | L3 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 6.80 X 10-06 | L3 | Non-volatile | |
GUS leaching potential index  |
2.69 | Calculated | Transition state | |
| SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate |
Value | 2.11 X 10-01 | Calculated | - |
| Note | - | |||
| Potential for particle bound transport index |
- | Calculated | Medium | |
| 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) | 135 | L3 | Persistent |
| DT50 (lab at 20oC) | 90 | F3 | Moderately persistent | |
| DT50 (field) | - | - | - | |
| DT90 (lab at 20oC) | - | - | - | |
| DT90 (field) | - | - | - | |
| DT50 modelling endpoint | - | - | - | |
| Note | Best available data | |||
| 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 | 290 | L3 | Stable |
| Note | - | |||
| Aqueous hydrolysis DT50 (days) at 20oC and pH 7 | Value | Stable | W4 | - |
| Note | - | |||
| Water-sediment DT50 (days) | - | - | - | |
| Water phase only DT50 (days) | - | - | - | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | H3 | Moderately mobile |
| Koc | 420 | |||
| Notes and range | - | |||
| Freundlich | Kf | - | - | - |
| Kfoc | - | |||
| 1/n | - | |||
| Notes and range | - | |||
| pH sensitivity | - | |||
Key metabolites:
| Metabolite | Formation medium | Estimated maximum occurrence fraction | 1107/2009 relevancy |
|
| methylcyclohexylurea | Soil | - | Not assessed under 91/414 or 1107/2009 | |
| methylcyclohexylamine | Soil | - | Not assessed under 91/414 or 1107/2009 | |
| phenylurea (Ref: IN-B5685) |
Soil | 0.170 | Not assessed under 91/414 or 1107/2009 | |
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | 84 | Q2 Estimated | Low potential |
| CT50 (days) | Not available | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | > 7500 | F4 Rat | Low | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | L2 Rat, 2 year | - |
| (ppm diet) | 500 | - | ||
| Birds - Acute LD50 (mg kg-1) | 10000 | L3 Colinus virginianus | Low | |
| Birds - Short term dietary (LC50/LD50) | - | - | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | 8.1 | F4 Oncorhynchus mykiss | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | - | - | - | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | > 13.7 | F4 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) | > 0.25 | L3 Raphidocelis subcapitata | Moderate | |
| 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) | 120 | F4 | 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 siduron
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) | > 7500 | F4 Rat | Low | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 5500 | F4 Rabbit | - | |
| Mammals - Inhalation LC50 (mg l-1) | > 5.8 | L3 Rat | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | 0.14 | L3 | - | |
| 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 | - | ||
| Occupational | - | |||
| 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 | |||
|
A3; B0; C0; D0; E0 | - |
- |
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- |
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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 | |||||||
| 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 |
No information available | |||
| CLP classification 2013 | Health: H315, H319 Environment: H410, H412 |
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| EC Risk Classification |
Xi - Irritant: R36/37/38 N - Dangerous for the environment: R52/53 |
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| EC Safety Classification |
S26, S61 | |||
| WHO Classification | U | - | Unlikely to present an acute hazard | |
| UN Number | - | |||
| Waste disposal & packaging |
- | |||
| Language | Name |
| English | siduron |
| French | siduron |
| German | Siduron |
| Danish | siduron |
| Italian | siduron |
| Spanish | siduron |
| Greek | - |
| Slovenian | siduron |
| Polish | siduron |
| Swedish | - |
| Hungarian | - |
| Dutch | - |
Record last updated: Tuesday 02 July 2019
Contact: aeru@herts.ac.uk