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Dalapon-sodium
Last updated: 04/01/2021
(Also known as: dalapon; proprop; DPA)

SUMMARY
Dalapon sodium is a selective herbicide that is not approved for use in the EU. It is highly soluble in water and volatile. Based on its chemical properties it has a tendency to leach to groundwater. Data suggests it is moderately persistent in soil systems and can be persistent in some water systems. It is relatively non-toxic to mammals and has a low potential for bioaccumulation. Dalapon sodium is a recognised irritant. It has a moderate toxicity to most aquatic organisms and honeybees but is less harmful to birds and earthworms.
Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate Ecotoxicity Human health
Environmental fate
High alert:
GUS: High leachability
Ecotoxicity
Moderate alert:
Daphnia acute ecotoxicity: Moderate; Bees acute unknown ecotoxicity: Moderate
Human health
Low alert
Warning:
Significant data are missing
GENERAL INFORMATION
Description
A herbicide used to control annual and perennial grasses including couch
Example pests controlled
Bluegrass; Crabgrass; Quackgrass; Bermudagrass Johnsssongrass; Cattails; Rushes; Barnyardgrass; Couch
Example applications
Cotton; Fruit including currants, plums, apricots, cherries, citrus; Potatoes; Sugarcane; Carrots; Alfalfa; Asparagus; Flax; Lucerne; Non-crop situations including domestic houses, commerical and industrial sites
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1954, first year of public use
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
Listed in EU database
Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States
ATAustria
BEBelgium
BGBulgaria
CYCyprus
CZCzech Republic
DEGermany
DKDenmark
EEEstonia
ELGreece
                 
ESSpain
FIFinland
FRFrance
HRCroatia
HUHungary
IEIreland
ITItaly
LTLithuania
LULuxembourg
                 
LVLatvia
MTMalta
NLNetherlands
PLPoland
PTPortugal
RORomania
SESweden
SISlovenia
SKSlovakia
                 
Also used in
Also used in
Australia
Chemical structure
Isomerism
-
Chemical formula
C₃H₃Cl₂NaO₂
Canonical SMILES
CC(C(=O)[O-])(Cl)Cl.[Na+]
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
PDEFQWNXOUGDJR-UHFFFAOYSA-M
International Chemical Identifier (InChI)
InChI=1S/C3H4Cl2O2.Na/c1-3(4,5)2(6)7;/h1H3,(H,6,7);/q;+1/p-1
2D structure diagram/image available?
Yes
General status
Pesticide type
Herbicide
Substance group
Halogenated aliphatic compound
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Selective, systemic absorbed through leaves and roots. Inhibition of lipid synthesis.
CAS RN
127-20-8
EC number
204-828-5
CIPAC number
52
US EPA chemical code
028902
PubChem CID
517058
Molecular mass
164.95
PIN (Preferred Identification Name)
sodium 2,2-dichloropropanoate
IUPAC name
sodium 2,2-dichloropropionate
CAS name
sodium 2,2-dichloropropionate
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
Z
Herbicide Resistance Classification (WSSA)
0
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
-
Physical state
Pale-coloured powder
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Radapon
  • Dowpon
  • basinex
  • Revenge
  • Alatex
  • Ded-Weed
Example products using this active
  • Shell
  • Dow Chemicals
  • BASF
  • Diamond Shamrock
Formulation and application details
Usually supplied as a water-soluble powder
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
629000
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
110000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Ethanol
-
369000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol
-
3250
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
20
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Benzene
-
Melting point (°C)
166.5
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Decomposes
-
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
6.92 X 1000 Calculated -
Log P
0.84
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Low
Bulk density (g ml⁻¹)
1.74
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
1.79
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Strong acid
Vapour pressure at 20 °C (mPa)
0.017
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
Surface tension (mN m⁻¹)
- - -
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
30
W2 W = French database provided by ARVALIS-Institut du Végétal
2 = Unverified data of unknown source
Moderately persistent
DT₅₀ (lab at 20 °C)
30
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Moderately persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
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
- - -
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
Stable
W4 W = French database provided by ARVALIS-Institut du Végétal
4 = Verified data
Stable
Note
Temperature sensitive, slow at 25 °C but quite rapid at 50 °C
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
DW3 DW = Don Wauchope personal database for Pka data: Wauchope, R. D. and Edwards, J. Dissociation constants for pesticide active ingredients: a database and comparison with predicted values. MS in preparation
3 = Unverified data of known source
Very mobile
Koc
1
Notes and range
Other sources: 2.34-151.4 mL g⁻¹ (R3)
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
5.91 Calculated High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
2.86 X 1000 Calculated -
Note
-
Potential for particle bound transport index
- - -
Potential for loss via drain flow
- - -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
2.5
P4 P = Other governments and regulators
4 = Verified data
Low potential
CT₅₀ (days)
Not available -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
9330
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Short term dietary NOEL
(mg kg⁻¹)
15
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 year
High
(ppm diet)
- -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
5660
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Gallus gallus
Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 100
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Oncorhynchus mykiss
Low
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
6
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Unknown species
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)
20
W2 W = French database provided by ARVALIS-Institut du Végétal
2 = Unverified data of unknown source
Unknown species
Low
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)
- - -
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)
> 50
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Moderate
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)
1058
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
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
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
High (class III) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
9330
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
- - -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
- - -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
- - -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
-
Occupational
-
MRLs
European
EU MRL pesticide database 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
XNo, known not to cause a problem
No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
Yes, known to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Possible kidney toxicant
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H315, H318
Environment: H412
EC Risk Classification
Xn - Harmful: R22, R41
Xi - Irritant: R38
N - Dangerous for the environment: R52, R53
EC Safety Classification
S2, S26, S39, S61
WHO Classification
U (Unlikely to present an acute hazard)
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
dalapon-sodium
French
dalapon sodium
German
Dalapon natrium
Danish
dalapon natrium
Italian
dalapon sodio
Spanish
dalapon sodio
Greek
-
Polish
dalapon sodowy
Swedish
-
Hungarian
-
Dutch
dalapon natrium

Record last updated: 04/01/2021
Contact: aeru@herts.ac.uk
Please cite as: Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242