Potassium isopentyl dithiocarbonate

Long-term toxicity to fish

Description of key information

Available weight of evidence on chronic toxicity to fish suggest 28-d NOEC (reproduction) value of 0.79 mg/L  based on the analogue substance potassium amyl xanthate.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.79 mg/L

Additional information

There are no scientifically valid chronic toxicity data available on the target substance. As there are studies available for the minor constituent and analogue substance potassium amyl xanthate (PAX), these study results were used in CSA as read-across data to evaluate the long-term toxicity of the target substance. As the studies were not considered reliable they were used as a weight of evidence. The read-across justification is presented in Annex I of CSR.

Webb et al. (1976) compared 96-h acute and 28-d chronic toxicities of mining flotation reagents to rainbow trout (Oncorhynchus mykiss, reported as Salmo Gairdneri). The 28-d LC50 on read-across substance PAX was > 1 mg/L at at pH 8 and temperature of 10.5 ^oC, and it had lowest chronic toxicity of the four xanthates tested. Except for PAX, the observed difference in toxicity for the same compounds between (acute) static and (chronic) flow-through bioassays was up to two orders of magnitude greater in the (chronic) flow-through tests. Inconsistently, out of the four xanthates tested, PAX had the highest acute toxicity but lowest chronic toxicity. As insufficient details on test materials and methods were available to assess the method applied, and no information on statistics and controls were reported in the publication, the results are rated as reliable with restrictions.

Leduc et al.(1975) examined chronic aquatic toxicity of xanthates, arsenic compounds and cyanide to rainbow trout (Oncorhynchus mykiss, reported as Salmo Gairdneri). The read-across substance PAX was concluded to cause liver necrosis already at concentration of 0.07 mg/L level and additionally disturb development of eggs in the ovary at the 0.79 mg/L level of exposure. The study was conducted for 28 days in a flow-through system at temperature of 10.5 ^oC. As insufficient details on test materials, methods, statistics and validation criteria were reported, the results are rated as not reliable.

In conclusion, the weight of evidence obtained for chronic toxicity of potassium amyl xanthate would suggest NOEC value of 0.79 mg/L to fish (reproduction).