Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.002 mg/L
Assessment factor:
50
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
0.014 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0 mg/L
Assessment factor:
500
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
100 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
0.934 mg/kg sediment dw
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.093 mg/kg sediment dw
Assessment factor:
1 000
Extrapolation method:
assessment factor

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
0.275 mg/kg soil dw
Assessment factor:
1 000
Extrapolation method:
assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
1.11 mg/kg food
Assessment factor:
90

Additional information

Discussion and details of derivation of PECsoil

 

Summary:

PNEC

Assessment factor

Remarks/Justification

PNEC soil: 0.275 mg/kg soil dw

1000

Extrapolation method: assessment factor

Short-term toxicity to plants (OECD 208): EC50: 275 mg/kg (for most sensitive species: tomato)

Short-term tests are available for earthworms, plants and soil micro-organisms.The lowest EC50 is selected.

Just for comparison purposes:

PNEC soil: 0.46 mg/kg soil dw

-

Extrapolation method: partition coefficient

Based on a PNECwater value of 0.0018 mg/L, PNECsoil has been estimated by the equilibrium partitioning method (EPM; for calculation details see further below)

 

 

Calculation of PNECsoil with assessment factor

Since September 2013 terrestrial short-term studies with cloquintocet-mexyl are available for earthworms, plants and soil micro-organisms. The lowest EC50 value has been found in the plant study (OECD 208): EC50: 275 mg/kg soil dw for species Lycopersicon esculentum (tomato). Based on this value and the default assessment factor of 1000, PNECsoil is 0.275 mg/kg soil dw. The corresponding value on the basis of the equilibrium partition method (EPM) is calculated further below for comparison purposes (result: 0.463 mg/kg soil dw). However it has not been used for the risk assessment.

 

Calculation of PNECsoil with EPM

The calculation of PNECsoil from PNECwater using the equilibrium partitioning method (EPM) is discussed and described in the following guidance documents:

Guidance on information requirements and chemical safety assessment, Chapter R.10: Characterisation of dose [concentration]-response for environment (May 2008)

Guidance on information requirements and chemical safety assessment, Chapter R.16: Environmental Exposure Estimation (V2.1, October 2012)

 

The calculation details are given in Equations R.10-5, R.16-4, R.16-5, R.16-6, R.16-7, R.16-16 and in Table R.16-9. The involved input, default and output values are, with their symbols and units, given in the following table.

Remark: The value given in guidance R.10 on page 40 for RHOsoil (bulk density of wet soil) is considered wrong (value given: 1150 kg m-3, correct value: 1700 kg m-3; this assumption is supported by Equation R.16-16).

 

Molecular weight

MOLW

[g/mol]

335.8

Input

Vapour pressure

VP

[Pa]

5.31E-06

Input

Solubility in water

SOL

[mg/L]

0.59

Input

Henry’s law constant

HENRY

[Pa/m3/mol]

0.0030222

Output

Gas constant

R

[Pa/m3/mol/K]

8.314

Default

Temperature at the air-water interface

TEMP

[K]

285

Default

Air-water partitioning coefficient

Kair-water

[-]

1.2755E-06

Output

Partition coefficient organic carbon-water

Koc

[L/kg]

12850

Input

Fraction organic carbon in the soil

Foc

[-]

0.02

Default

Soil water partition coefficient

Kpsoil

[L/kg]

257

Output

Fraction air in soil

Fair

[-]

0.2

Default

Fraction water in soil

Fwater

[-]

0.2

Default

Fraction solid in soil

Fsolid

[-]

0.6

Default

Bulk density of solids

RHOsolid

[kg/m3]

2500

Default

Soil-water equilibrium partition distribution coefficient

Ksoil-water

[m3/m3]

385.7

Output

Bulk density of wet soil

RHOsoil

[kg/m3]

1700

Default

Bulk density of dry soil

RHOsoil dry

[kg/m3]

1500

Default

 

The final calculation of PNECsoil is made according to the following equation:

PNECsoil = (Ksoil-water/RHOsoil) * PNECwater * 1000

with [PNECsoil]: mg/kg, [PNECwater]: mg/L, [RHOsoil]: kg/m3

 

Based on PNECwater of 0.0018 mg/L and the default values for the bulk density of soil (1700 kg/m3 for wet soil and 1500 kg/m3 for dry soil) the following values PNECsoil, based on EPM, were derived:

PNECsoil: 0.408 mg/kg (EPM, based on wet soil)

PNECsoil: 0.463 mg/kg (EPM, based on dry soil)

 

Remark: In REACH guidance documents (i.e. R.7c, R.10) it is suggested that for risk assessments of substances with a high potential to partition to soil the PEC/PNEC ratios based on EPM should be multiplied a factor of 10 in order to take into account the uptake by soil ingestion due to adsorption of the substance to soil. The relevant parameter to describe the adsorption potential to soils is Koc. Log Koc of cloquintocet-mexyl is 4.1 (based on mean Koc of 12850 mL/g) and thus less than 5. Thus no additional factor 10 is required for cloquintocet-mexyl.

Conclusion on classification

Cloquintocet-mexyl is currently classified

- for "environmental effects, aquatic environment" under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC, Annex VI, 5.2.1: dangerous for the environment, R50/53 (very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment)

- for "environmental hazards, hazardous to the aquatic environment" under Regulation (EC) 1272/2008, Annex I, Part 4, 4.1: acute, category 1, H400 (Very toxic to aquatic life)

- for "environmental hazards, hazardous to the aquatic environment" under Regulation (EC) 1272/2008, Annex I, Part 4, 4.1: chronic, category 1, H410 (very toxic to aquatic life with long lasting effects)

 

However this classification might be reviewed by the lead registrant in the future (with aim to result in a less hazardous classification).