dichloromethane; methylene chloride

Long-term toxicity to fish

Description of key information

The 28-d NOEC value for the freshwater fish Pimephales promelas is 83 mg/l from an early life stage (28-day) test.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

83 mg/L

Additional information

Four long-term studies have been conducted with early life stages of 4 different freshwater fish species. Only 1 of these was conducted to recognised guidelines, with analysis, and considered valid. This study was performed with eggs and larvae of Pimephales promelas in a flow-through system, giving a 28-d NOEC for growth of the larvae of 83 mg/L based on measured concentrations (Dill et al, 1987). Hatchability and survival were less sensitive, with 28-d NOECs of 321 and 142 mg/L, respectively.

Another study with eggs and larvae of Pimephales promelas was carried out in a flow-through system with analysis (Black et al.,1982). The 9-d LC50 (34 mg/L) was several times lower than the 28-d NOEC described above. However, the interval between test concentrations was wide (up to a factor of 10; where according to test guidelinesthe test concentration is spaced by a constant factor not exceeding a factor of 3.2). Furthermore, there was no information provided concerning the mortality in the controls. Therefore it cannot be assured that control exposure passed test validity. The study is therefore not considered valid. A similar early life stage study with Onchorhynchus mykiss from the same authors (Black et al.,1982) giving a 27-d LC50 of 13.16 mg/L is also considered non-valid for the same reasons as described above.