Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]-, 1-methylhexyl ester

Ecotoxicological Summary

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 terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.463 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

1.11 mg/kg food

Assessment factor:

90

Additional information

Derivation of PNECsoil

 

PNEC	Assessment factor	Remarks/Justification
PNEC soil: 1 mg/kg soil dw	1000	Extrapolation method: assessment factor Short-term toxicity to invertebrates (earthworm, OECD 207): LC50: >1000 mg/kg Only a single short-term test is available which is adequate for the risk assessment under REACH. According to Table R.10-10, an assessment factor of 1000 is used.
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)

 

Remarks:

·        Based on guidance R.10, the risk assessment should be performed with both values if only one terrestrial test result is available. Thus the lower value, in this case the value derived with EPM, will determine the outcome of the risk assessment.

·        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.

 

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, May 2010)

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 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).

 

Variable/parameter (unit)	Symbol	Unit	Value	Source
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/m^3/mol]	0.0030222	Output
Gas constant	R	[Pa/m^3/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	[m^3/m^3]	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)

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: chronic, category 1, H410 (very toxic to aquatic life with long lasting effects)

 

However this classification is currently under review by the lead registrant.