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chloridazon (Ref: BAS 119H)
** pyrazon ** pyrazone ** PAC ** chloridazone ** Translations

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SUMMARY

Choridazon is a herbicide approved fro use in the EU. It has a moderate aqueous solubility and is not considered to be volatile. It is moderately persistent in soil system and can also be persistent in water systems under some conditions. It has a low oral mammalian toxicity and whilst it is a recognised skin and eye irritant no chronic health impacts have been identified. It shows moderate to low ecotoxicity to most species.

GENERAL INFORMATION Click here for an explantaion of the general chemical status information
for chloridazon

Description: A residual pyridazinone herbicide for control of weeds in beet and other crops crops

Example pests controlled: Broad-leaf and grass weeds including blackgrass, canary grass and wild oats

Example applications: Sugarbeet; Fodder beet; Red beet; Mangels; Onions; Shallots; Garlic; Ornamentals

Efficacy & activity: -

Availability status: Current

Introduction & key dates: 1964

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Germany
Date inclusion expires 31/12/2018
EU Candidate for substitution (CfS) No
Listed in EU database Yes

Approved for use () or known to be used () in the following European countries: Click to access a note on the approvals information on this site

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

Also used in: Australia

Chemical structure: Click here for further information on the general chemical status information used on this site
Isomerism Isomeric - the 4-amino-5-chloro-isomer is a common impurity
Chemical formula C10H8ClN3O
Canonical SMILES C1=CC=C(C=C1)N2C(=O)C(=C(C=N2)N)Cl
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) WYKYKTKDBLFHCY-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C10H8ClN3O/c11-9-8(12)6-13-14(10(9)15)7-4-2-1-3-5-7/h1-6H,12H2
Structure diagram/image available? Yes

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Herbicide
Substance group Pyridazinone
Minimum active substance purity 920 g/kg
Known relevant impurities EU dossier - 5-chloro isomer <60 g/Kg
Substance origin Synthetic
Mode of action Selective, systemic. Inhibits photosynthesis (photosystem II).
CAS RN 1698-60-8
EC number 216-920-2
CIPAC number 111
US EPA chemical code 069601
PubChem CID 15546
Molecular mass (g mol-1) 221.6
PIN (Preferred Identification Name) 5-amino-4-chloro-2-phenylpyridazin-3(2H)-one
IUPAC name 5-amino-4-chloro-2-phenylpyridazin-3(2H)-one
CAS name 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone
Other status information -
Relevant Environmental Water Quality Standards -
Herbicide Resistance Classification (HRAC) C1
Herbicide Resistance Classification (WSSA) 5
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance -
Physical state Colourless crystalline solid
Related substances & organisms

Formulations:
Property Click here for information on the general product and branding information used on this site Value
Example manufacturers & suppliers of products using this active now or historically
  • AgriGuard
  • BASF
  • Nufarm
  • Sipcam
  • Du Pont
Example products using this active
  • Ashlade CP
  • Magnum
  • Pyramin DF
  • Takron
  • Questar
  • BREK
UK LERAP status None
Formulation and application details Supplied in a variety of formulations including suspension concentrates and wettable powders.


ENVIRONMENTAL FATE

for chloridazon

Property Click here for information on the parameters used to describe environmental fate on this site Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with fate data Interpretation Click here for information on the way in which we interpret environmental fate data
Solubility - In water at 20oC (mg l-1) 422 A5 Moderate
Solubility - In organic solvents at 20oC (mg l-1) 15100 A5 - Methanol -
3700 A5 - Ethyl acetate -
100 A5 - Toluene -
190 A5 - Dichloromethane -
Melting point (oC) 206 A5 -
Boiling point (oC) Decomposes before boiling A3 -
Degradation point (oC) 360 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 1.55 X 1001 Calculated -
Log P 1.19 A5 Low
Bulk density (g ml-1)/Specific gravity 1.51 A5 -
Dissociation constant (pKa) at 25oC 3.38 V3 -
Note: Very weak acid
Vapour pressure at 20oC (mPa) 1.0 X 10-06 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 5.30 X 10-10 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index 2.78 Calculated Transition state
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Click here for a note on the limitations of the SCI-GROW index Value 2.19 X 10-01 Calculated -
Note -
Potential for particle bound transport index Click here for a note on the limitations of the potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 210nm = 18577, 229nm = 25043, 286nm = 10088 A5 -
Surface tension (mN m-1) 72.0 A5 -

Degradation:
Property Click here for information on the parameters used to describe substance degradation Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with degradation data Interpretation Click here for information on the way in which we interpret substance degradation data
General biodegradability -
Soil degradation (days) (aerobic) DT50 (typical) 31 K4 Moderately persistent
DT50 (lab at 20oC) 43.1 A5 Moderately persistent
DT50 (field) 34.7 A5 Moderately persistent
DT90 (lab at 20oC) 86 A5 -
DT90 (field) 103 A5 -
DT50 modelling endpoint - - -
Note EU dossier lab studies DT50 range 8.6-173.9 days, DT90 range 50-140 days; field studies DT50 range 3-97 days, DT90 range 35-214 days; Other sources: DT50 21.0 days (DW3)
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 40 A5 Stable
Note -
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable at all pH for over 30 days
Water-sediment DT50 (days) 137 A5 Slow
Water phase only DT50 (days) 51.5 A5 Stable

Soil adsorption and mobility:
Property Click here for information on the parameters used to describe substance adsorption and mobility Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with adsorption and mobility data Interpretation Click here for information on the way in which we interpret substance adsorption and mobility
Linear Kd - DW3 Moderately mobile
Koc 120
Notes and range -
Freundlich Kf 1.1 A5 Moderately mobile
Kfoc 199
1/n 0.845
Notes and range EU dossier Kf range 0.2-3.6 mL/g, Kfoc range 89-340 mL/g, 1/n range 0.568-1.03, Soils=5
pH sensitivity No

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
5-amino-4-chloro-3(2H)-pyridazinone This metabolite may cause environmental pollution, click here for further information Soil   0.559   Major fraction, Relevant
5-amino-4-chloro-2-methyl-3(2H)-pyridazinone Soil   -   Minor fraction, Not relevant

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
- chloridazon metabolite A Animal; Plant; Soil; Surface water - -
- chloridazon metabolite B-glucoside Plant - -
5-amino-4-chloro-2-methyl-3(2H)-pyridazinone
Note: DT50 soil 144 days
chloridazon metabolite B-1 Plant - -
5-amino-4-chloro-2-(4-hydroxyphenyl)-3(2H)-pyridazinone 4-OH-chloridazon; BH 119-4-OH Animal; Rat (Urinary, Bile, Faeces) - -
5-amino-4-chloro-2-(4-sulfatophenyl)-3(2H)-pyridazinone sulfate conjugate of BH 119-4-OH Animal; Rat - -
5-amino-2-phenyl-3(2H)-pyridazinone deschloro-chloridazon Animal - -
5-amino-2-(4-sulfatophenyl)-3(2H)-pyridazinone sulfate conjugate of deschloro-chloridazon Rat - -
- glucuronide of BH 119-4-OH Rat - -


ECOTOXICOLOGY

for chloridazon

Property Click here for information on the parameters used to describe substance ecotoxicology Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with ecotoxicology data Interpretation Click here for information on the way in which we interpret substance ecotoxicology
Bio-concentration factor BCF (l kg-1) 12 P4 Low potential
CT50 (days) Not available -
Mammals - Acute oral LD50 (mg kg-1) 2140 A5 Rat Low
Mammals - Short term dietary NOEL (mg kg-1) 16 L2 Rat, 2 year High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) > 2000 A5 Colinus virginianus Low
Birds - Short term dietary (LC50/LD50) > 1318 mg kg bw-1 day-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 41.3 A5 Oncorhynchus mykiss Moderate
Fish - Chronic 21 day NOEC (mg l-1) 3.16 A5 Oncorhynchus mykiss Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 132.0 A5 Daphnia magna Low
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 6.23 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) - - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) - - -
Aquatic plants - Acute 7 day EC50, biomass (mg l-1) > 3.16 A5 Lemna gibba Moderate
Non-target plants - - -
- - -
Algae - Acute 72 hour EC50, growth (mg l-1) > 3.0 A5 Pseudokirchneriella subcapitata Moderate
Algae - Chronic 96 hour NOEC, growth (mg l-1) 0.73 Q2 Unknown species Moderate
Honeybees Contact acute 48 hour LD50 (μg bee-1) > 200 A5 Low
Oral acute 48 hour LD50 (μg bee-1) > 200 A5 Low
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) > 1000 A5 Eisenia foetida Low
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 3.2 Mortality
Dose: 0.26 Kg ha-1
A5 Typhlodromus pyri
-
Other arthropod (2) LR50 g ha-1 - - -
% Effect 0.0 Mortality
Dose: 2.6 Kg ha-1
A5 Aphidius rhopalosiphi
-
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
A5
Dose: 26 mg kg-1 soil
-
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for chloridazon

General:
Property Click here for information on the parameters used to describe human health and protection issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with human health and protection data Interpretation Click here for information on the way in which we interpret human health and protection data
Threshold of Toxicological Concern (Cramer Class) Click here for a note on the limitations of the Cramer class High (class III) - -
Mammals - Acute oral LD50 (mg kg-1) 2140 A5 Rat Low
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) > 5.4 A5 Rat, 4 hr -
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) None allocated A5 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.2 A5 Rat, SF=100 -
Dermal penetration studies (%) 4 A5 -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public Acceptable risk for bystanders for proposed uses
Occupational Acceptable risk for operators and other workers for proposed uses
European MRLs Click here for the EU MRL pesticide database
Drinking Water Standards - - -
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant

-

-

Respiratory tract irritant Skin irritant Skin sensitiser Eye irritant Phototoxicant

-

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 Click here for information on the parameters used to describe substance handling issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with data on handling issues Interpretation Click here for information on the way in which we interpret data on handling issues
General Click here for a description of the International Maritime Dangerous Goods (IMDG) codes Not explosive
IMDG Transport Code is usually 9
CLP classification 2013 Health: H317
Environment: H400, H410
EC Risk Classification Click here to view information omn the EU risk phrases Xn - Harmful: R43
N - Dangerous for the environment: R50, R53
EC Safety Classification Click here to view information omn the EU safety phrases S2, S24, S37, S60, S61
WHO Classification III - Slightly hazardous
US EPA Classification (formulation) III - Caution - Slightly toxic
UN Number Variable with product, usually 3077 or 3082
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group III (minor danger)


TRANSLATIONS

for chloridazon

Language Name
English chloridazon
French chloridazone
German Chloridazon
Danish chloridazon
Italian chloridazon
Spanish cloridazon; pirazona
Greek -
Slovenian kloridazon
Polish chlorydazon
Swedish kloridazon
Hungarian chloridazon
Dutch chloridazon

Record last updated: Thursday 23 August 2018
Contact: aeru@herts.ac.uk
© University of Hertfordshire