Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
3.67 µg/L
Assessment factor:
1 000
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
0.037 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.367 µg/L
Assessment factor:
10 000
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
no emission to STP expected

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
4.8 µg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.48 µg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
1.6 µg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

The hazard assessment of this substance in the water compartment was based on the lowest short-term toxicity test results of three taxonomic groups (algae, crustaceans and fish) and the use of assessment factors. As there were neither short-term nor long-term aquatic toxicity test results available for marine organisms, the PNEC for marine water was also derived based on the aquatic fresh water toxicity. The lowest short-term aquatic toxicity of the substance was determined to daphnids (Daphnia magna) with EC50 (48h) value of 3.67 mg/L (inhibition of mobility). Hazard assessment to sewage treatment microbes was not conducted, as there are no emissions to the STP.

As there was no ecotoxicological data of the substance available for sediment-dwelling organisms or soil organisms, the PNECs for sediments and soil compartment were determined based on the partitioning method by using the PNECs derived for the water compartment and the measured adsorption coefficient of the substance (Koc 24.21). As concluded in the chemical safety assessment, PIAX and its main reaction products are degradable and will not bioaccumulate. No PNEC oral needs therefore be derived.

Conclusion on classification

The following data was used in classification and labelling of potassium isoamyl xanthate:

Aquatic acute toxicity:

48-h EC50 (immobilisation) D.magna, 3.67 mg/l (OECD 202, GLP)

72-h EC50 (growth rate) Desmodesmus subspicatus, 10.51 mg/l (OECD 201, GLP)

96-h LC50 (mortality) Danio rerio, 10 mg/l (OECD 203, GLP), read-across data from potassium isobutyl xanthate

Conclusion: no acute toxicity as the lowest toxicity value is > 1 mg/l.

Aquatic chronic toxicity:

72 -h NOEC (growth rate) Desmodesmus subspicatus,1 mg/l (OECD 201, GLP)

28-d NOEC (reproduction) Oncorhynchus mykiss, 0.79 mg/l (non guideline study (Klimisch score 3); read-across from potassium amyl xanthate)

Biodegradation:

Laboratory studies on biodegradation water screening (read-across data), no studies on the target substance:

98 % of the analogue substance was degraded in 12 days. 75 % of the substance was degraded in 5 days (modified Zahn-Wellens test (OECD 302 B). Read-across data from potassium isobutyl xanthate (PIBX). Results indicate that the test substance is inherently biodegradable.

Abiotic degradation is the driving force for the degradation of the substance in use applications. Hydrolysis is not rapid (47 to 247 days at 17 to 0 deg. C). Conclusion: Not readily biodegradable.

Bioaccumulation and/or persistence:

No potential for bioaccumulation as log Kow -0.76 (estimate with EPISUITE; US EPA 2013)

Conclusion: Aquatic chronic toxicity as the reliable short-term toxicity value (D.magna) is between 1 -10 mg/l and the substance is not considered readily biodegradable.

Classification and labeling according to CLP 1272/2008:

Aquatic Chronic Cat 2 (H411)

Classification and labeling according to DSD 67/548/EEC:

N, R51 -R53