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contact
diquat dibromide
** diquat ** deiquat ** reglone ** Translations

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SUMMARY

Diquat dibromide is an EU approved contact desiccant and herbicide. It is highly soluble in water, has a low risk of leaching to groundwater and is volatile. It is very persistent in soil but rapidly degrades in aquatic systems. It is moderately toxic to mammals and is a known irritant but no other significant human health issues have been identified. It is moderately toxic to birds, most aquatic organisms, honeybees and earthworms.

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

Description: A non-residual bupyridyl herbicide and crop desiccant used mainly to control broad-leaved weeds and grasses

Example pests controlled: Water lettuce; Water hyacynth; Duckweed; Pennywort; Annual bluegrass; Fescue; Henbit; Buttercup

Example applications: Potatoes; Oilseed rape; Fruit including apples, pears, peaches, plums, citrus, olive, grapes; Tomatoes; Sunflowers; Vegetables including beans & peas, carrots, onions, chicory; Sugarbeet

Efficacy & activity: -

Availability status: Current

Introduction & key dates: 1958, first reported; 1962, first marketed

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur UK/Sweden
Date inclusion expires 30/06/2019
EU Candidate for substitution (CfS) Yes - low ADI / ARfD / AOEL; two 'Persistent-Bioaccumulative-Toxic' criteria
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, USA

Chemical structure: Click here for further information on the general chemical status information used on this site
Isomerism None
Chemical formula C12H12N2Br2
Canonical SMILES C1C[N+]2=CC=CC=C2C3=CC=CC=[N+]31.[Br-].[Br-]
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) ODPOAESBSUKMHD-UHFFFAOYSA-L
International Chemical Identifier (InChI) InChI=1S/C12H12N2.2BrH/c1-3-7-13-9-10-14-8-4-2-6-12(14)11(13)5-1;;/h1-8H,9-10H2;2*1H/q+2;;/p-2
2D structure diagram/image available? Yes

Click to access the Cambridge Crystallographic Data Centre (CCDC) website
Cambridge Crystallographic Data Centre diagrams:
Common Name Relationship Link
Diquat dibromide - Click here for the CCDC structure diagram

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Herbicide
Substance group Bipyridylium
Minimum active substance purity 95% w/w
Known relevant impurities EU dossier - dibromoethane; 2,2-bipyridine; terpyridine & related isomers
Substance origin Synthetic
Mode of action Non-selective, contact absorbed through foliage, some desiccant action. Photosystem I (electron transport) inhibitor.
CAS RN 85-00-7
EC number 201-579-4
CIPAC number 55
US EPA chemical code 032201
PubChem CID 6794
Molecular mass (g mol-1) 344.05
PIN (Preferred Identification Name) 6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazine-5,8-diium dibromide
IUPAC name 9,10-dihydro-8a,10a-diazoniaphenanthrene dibromide
CAS name 6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide
Other status information Potential groundwater contaminant; PAN listed Highly Hazardous Chemical
Relevant Environmental Water Quality Standards -
Herbicide Resistance Classification (HRAC) D
Herbicide Resistance Classification (WSSA) 22
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance -
Physical state White/yellow crystals
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
  • Clayton
  • Standon
  • Syngenta
  • ICI Plant Protection
Example products using this active
  • Reglone
  • Retro
  • Quad
  • Googly
  • Weedol
  • Reglox
UK LERAP status None
Formulation and application details Often supplied as a soluble concentrate, gel or liquid concentrate.


ENVIRONMENTAL FATE

for diquat dibromide

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) 718000 A5 High
Solubility - In organic solvents at 20oC (mg l-1) 25000 A5 - Methanol -
100 A5 - Acetone -
100 A5 - Toluene -
100 A5 - Ethyl acetate -
Melting point (oC) Decomposes before melting A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 325 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 2.51 X 10-05 Calculated -
Log P -4.6 A5 Low
Bulk density (g ml-1)/Specific gravity 1.61 A5 -
Dissociation constant (pKa) at 25oC Not applicable A5 -
Note: No dissociation
Vapour pressure at 20oC (mPa) 0.01 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 5.00 X 10-12 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index -2.29 Calculated Low leachability
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 5.35 X 10-03 Calculated -
Note Estimated concentrations of chemicals with Koc values greater than 9995 ml g-1 are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW
Potential for particle bound transport index Click here for a note on the limitations of the potential for particle bound transport index - Calculated High
Maximum UV-vis absorption L mol-1 cm-1 204nm, 272nm, 310nm A3 -
Surface tension (mN m-1) - - -

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) 2345 A5 Very persistent
DT50 (lab at 20oC) 365 A1 Very persistent
DT50 (field) 5500 A5 Very persistent
DT90 (lab at 20oC) - - -
DT90 (field) - - -
DT50 modelling endpoint - - -
Note EU dossier lab studies DT50 range 598 to >1000 days; DT90 range 1985-20509 days; Other data: DT50 Lab studies - no measureable degradation after 1 year, field study DT50 range 1-20 years (UK)
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 7 A5 Moderately fast
Note -
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable pH 5 to pH 9
Water-sediment DT50 (days) 1 A5 Fast
Water phase only DT50 (days) 1 A5 Moderately fast

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 - A5 Non-mobile
Koc 2184750
Notes and range -
Freundlich Kf 1740 R4 Non-mobile
Kfoc 78274
1/n 3.85
Notes and range Kf range 288-7222 mL/g; Kfoc range 14400-144440 mL/g; 1/n range 1.7-5.0, Soils=9
pH sensitivity -

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
1-oxo-1,2,3,4-tetrahydropyrido(1,2-a)pyrazin-5-ium (Ref: R32245) Soil   0.099   Minor fraction; Relevant

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
1,2,3,4-tetrahydro-1-oxopyrido(1,2-a) pyrazin-5-ium ion - Water (Photolysis) - -


ECOTOXICOLOGY

for diquat dibromide

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) 1 F4 Whole fish Low potential
CT50 (days) Not available -
Mammals - Acute oral LD50 (mg kg-1) 1000 A5 Rat Moderate
Mammals - Short term dietary NOEL (mg kg-1) 8.9 A5 Rat High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) 71 A4 Anas platyrhynchos High
Birds - Short term dietary (LC50/LD50) 721 mg kg feed-1 A5 Coturnix japonica, as diquat ion -
Fish - Acute 96 hour LC50 (mg l-1) 67.0 A5 Oncorhynchus mykiss Moderate
Fish - Chronic 21 day NOEC (mg l-1) 0.22 P4 Pimephales promelas Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 1.2 A5 Daphnia magna Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 0.125 A5 Daphnia magna Moderate
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) 2.0 F4 Americamysis bahia Moderate
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1) - - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l-1) 1.27 A5 Chironomus riparius Moderate
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) > 100 A5 Chironomus riparius Low
Aquatic plants - Acute 7 day EC50, biomass (mg l-1) 0.0032 A5 Lemna gibba High
Non-target plants 15.4 A5 Brassica oleracea
Vegetative vigour, ER50
as g/ha
-
- - -
Algae - Acute 72 hour EC50, growth (mg l-1) > 0.011 A5 Psuedokirchneriella subcapitata Moderate
Algae - Chronic 96 hour NOEC, growth (mg l-1) 0.0068 Q2 Unknown species Moderate
Honeybees Contact acute 48 hour LD50 (μg bee-1) > 20.1 A5 Moderate
Oral acute 48 hour LD50 (μg bee-1) 50.7 A5 Moderate
Unknown mode acute 48 hour LD50 (μg bee-1) 24.3 P4 Moderate
Earthworms - Acute 14 day LC50 (mg kg-1) 94.3 A5 Eisenia foetida Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) 37 A5 Eisenia foetida Moderate
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 2.9 A5 Typhlodromus pyri -
% Effect 90
0
Mortality
Fecundity
Dose: Field rate 5 l ha-1
A2 Aphidius rhopalosiphi
-
Other arthropod (2) LR50 g ha-1 3.2 A5 Aphidius rhopalosiphi -
% Effect 98
-58
Mortality
Parasitism
Dose: 1 kg ha-1
A5 Trichogramma cacocecie, adult
-
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect [Dose: 50 kg ha-1]
Carbon mineralisation: No significant adverse effect [Dose: 720 kg ha-1]
A5 -
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for diquat dibromide

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) 1000 A5 Rat Moderate
Mammals - Dermal LD50 (mg kg-1 body weight) 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) > 0.5 A5 Rat -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.0024 A5 Rat, SF=100 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) 0.024 A5 Dog, SF=100 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.0024 A5 Dog, SF=100 -
Dermal penetration studies (%) 0.5 A5 -
Dangerous Substances Directive 76/464 - - -
Exposure Limits [UK LT TWA 8 hr: 0.5 mg/m3], [UK STEL 15 mins: 1.0 mg/m3] MEL UK HSE -
Exposure Routes Public Slight risk of dietary exposure
Occupational -
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 Potential liver, kidney, stomach and intestine toxicant
Fatal if inhaled

: 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 IMDG Transport Code is usually 6.1 or 8
Corrosive to most metals & may form flammable and explosive H2 gas when in contact with aluminum
May decompose at high temperatures to form toxic gases
CLP classification 2013 Health: H330, H302, H317, H335, H372, H315, H319
Environment: H400, H410
EC Risk Classification Click here to view information omn the EU risk phrases T+ - Very toxic: R26
T - Toxic: R48/25
Xn - Harmful: R22, R43
Xi - Irritant: R36/37/38
N - Dangerous for the environment: R50, R53
EC Safety Classification Click here to view information omn the EU safety phrases S1/2, S28, S36/37/39, S45, S60, S61
WHO Classification II - Moderately hazardous
US EPA Classification (formulation) II - Warning - Moderately toxic
UN Number 2781 for active, products usually 1760
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group III (minor danger)


TRANSLATIONS

for diquat dibromide

Language Name
English diquat dibromide
French diquat dibromure
German Deiquat dibromid
Danish diquat dibromid
Italian diquat dibromid
Spanish dicuat dibromid
Greek diquat dibromid
Slovenian dikvat dibromid
Polish dibromek dikwatu
Swedish dikvat dibromidsalt
Hungarian diquat dibromide
Dutch diquatdibromide

Record last updated: Tuesday 30 October 2018
Contact: aeru@herts.ac.uk
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