INTERNATIONAL UNION
   OF PURE AND APPLIED
   CHEMISTRY
contact
difenacoum
** difenacume ** coumarin ** Translations

Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home

SUMMARY

Difenacoum is a 2nd generation anticoagulant rodentcide that is currently approved for use in many countries including the EU. It has a low aqueous solubility, a low volatility, and would not generally be expected to leach to groundwater. It may be very persistent in soil systems under certain conditions. In water systems the predominant degradation process is photolysis. it is highly toxic to mammals with some evidence indicating that it may cause negative reproduction and/or fertiliy effects. There are gaps in ecotoxicological data but it is known to be highly toxic to birds and fish and moderately toxic to aquatic invertebrates.

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

Description: A rodenticide effective against rats and mice resistant to other anticoagulants

Example pests controlled: Rats; Mice; Other small rodents

Example applications: Rats; Mice; Other small rodents

Efficacy & activity: -

Availability status: Current

Introduction & key dates: 1976

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Finland
Date inclusion expires 30/12/2019
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 A chiral molecule
Chemical formula C31H24O3
Canonical SMILES C1C(CC2=CC=CC=C2C1C3=C(C4=CC=CC=C4OC3=O)O)C5=CC=C(C=C5)C6=CC=CC=C6
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) FVQITOLOYMWVFU-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C31H24O3/c32-30-26-12-6-7-13-28(26)34-31(33)29(30)27-19-24(18-23-10-4-5-11-25(23)27)22-16-14-21(15-17-22)20-8-2-1-3-9-20/h1-17,24,27,32H,18-19H2
Structure diagram/image available? Yes

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Rodenticide
Substance group Hydroxycoumarin
Minimum active substance purity -
Known relevant impurities EU dossier - None declared
Substance origin Synthetic
Mode of action 2nd generation anticoagulant
CAS RN 56073-07-5
EC number 259-978-4
CIPAC number 514
US EPA chemical code 11901
PubChem CID 54676884
Molecular mass (g mol-1) 444.52
PIN (Preferred Identification Name) 3-((1E,3E)-3-(1,1'-biphenyl)-4-yl-1,2,3,4-tetrahydronaphthalen-1-yl)-4-hydroxy-2H-1-benzopyran-2-one
IUPAC name 3-((1RS,3RS;1RS,3SR)-3-biphenyl-4-yl-1,2,3,4-tetrahydro-1-naphthyl)-4-hydroxycoumarin
CAS name 3-(3-(1,1'-biphenyl)-4-yl-1,2,3,4-tetrahydro-1-naphthalenyl)-4-hydroxy-2H-1-benzopyran-2-one
Other status information -
Relevant Environmental Water Quality Standards -
Herbicide Resistance Classification (HRAC) Not applicable
Herbicide Resistance Classification (WSSA) Not applicable
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance -
Physical state Colourless crystalline powder
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
  • Killgerm
  • Sorex
  • ICI Plant Protection
Example products using this active
  • Neokil
  • Sakarat D
  • Sorexa Gel
  • Neosorexa pellets
  • Ratak
UK LERAP status No UK approval for use as a pesticide under EC Regulation 1107/2009
Formulation and application details Usually supplied as ready-to-use baits.


ENVIRONMENTAL FATE

for difenacoum

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) 1.7 A5 Low
Solubility - In organic solvents at 20oC (mg l-1) 7600 A5 - Acetone -
3700 A5 - Ethyl acetate -
1200 A5 - Methanol -
19600 A5 - Dichloromethane -
Melting point (oC) 213 A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 300 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 3.98 X 1007 Calculated -
Log P 7.6 A4 High
Bulk density (g ml-1)/Specific gravity 1.27 Q2 -
Dissociation constant (pKa) at 25oC 4.84 A5 -
Note: Weak acid
Vapour pressure at 20oC (mPa) 1.9 X 10-08 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 5.0 X 10-09 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index -3.26 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-1 259.4nm = 466001; [310.6nm = 171001 A5 -
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) 290 L3 Persistent
DT50 (lab at 20oC) 439 A4 Very persistent
DT50 (field) - - -
DT90 (lab at 20oC) - - -
DT90 (field) - - -
DT50 modelling endpoint - - -
Note EU dossier lab studies DT50 439 days Speyer 2.2 soil, aerobic conditions
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 0.34 A5 Fast
Note pH sensitive: 3.3 hrs at pH 5, 8.1 hrs at pH 7, 7.3 hrs at pH 9
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value 1000 A5 Very persistent
Note Stable at 25 deg C
Water-sediment DT50 (days) - - -
Water phase only DT50 (days) - - -

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 - A3 Non-mobile
Koc 170700
Notes and range EU dossier Koc range 17-426579 mL/g - estimated by HPLC
Freundlich Kf - - -
Kfoc -
1/n -
Notes and range -
pH sensitivity Higher adsorption at lower pH


ECOTOXICOLOGY

for difenacoum

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) 9010 Q2 Estimated High potential
CT50 (days) Not available -
Mammals - Acute oral LD50 (mg kg-1) 1.8 A5 Rat High
Mammals - Short term dietary NOEL (mg kg-1) - - -
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) 56 A5 Colinus virginianus High
Birds - Short term dietary (LC50/LD50) 3.5 mg kg bw-1 day-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 0.064 A5 Oncorhynchus mykiss High
Fish - Chronic 21 day NOEC (mg l-1) - - -
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 0.52 A5 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) 0.32 A5 Selenastrum capricornutum Moderate
Algae - Chronic 96 hour NOEC, growth (mg l-1) - - -
Honeybees Contact acute 48 hour LD50 (μg bee-1) - - -
Oral acute 48 hour LD50 (μg bee-1) - - -
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
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 difenacoum

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) 1.8 A5 Rat High
Mammals - Dermal LD50 (mg kg-1 body weight) 63 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) 0.005 A5 Rat, 4 hr (head only) -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) None allocated A5 -
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) 0.000017 A5 Rabbit, SF=300 -
Dermal penetration studies (%) 3.0 A5 -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public -
Occupational Exceptable risks for operators even with out PPE/PPC
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 Highly toxic
May cause blood coagulation and haemorrhaging
Vapour may cause dizziness or suffocation

: 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 Prevent generation of dust
Not explosive or oxidising but vapour may form explosive mixtures with air
IMDG Transport Code is usually 6.1
CLP classification 2013 None allocated at this time
EC Risk Classification Click here to view information omn the EU risk phrases T+ - Very toxic: R28
T - Toxic: R48/25
N - Dangerous for the environment: R50, R53
EC Safety Classification Click here to view information omn the EU safety phrases S1/2, S36/37, S45, S60, S61
WHO Classification Ia - Extremely hazardous
US EPA Classification (formulation) No consensus across products or no products available - -
UN Number 3027
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group I (great danger)


TRANSLATIONS

for difenacoum

Language Name
English difenacoum
French difenacoum
German Difenacoum
Danish difenacoum
Italian difenacum
Spanish difenacum
Greek difenacoum
Slovenian difenakum
Polish difenakum
Swedish difenakum
Hungarian -
Dutch difenacum

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