Solvent naphtha (petroleum), medium aliph.

Toxicity to aquatic algae and cyanobacteria

Additional information

In a key 72-hour toxicity test (OECD 201; KS = 1), cultures of the freshwater plant Raphidocelis subcapitata were exposed to solvent naphtha (petroleum), heavy aromatic kerosine at nominal concentrations of 0, 0.1, 0.4, 1.0, 3.0, and 10.0 mg/L under static conditions. The 72-hour NOEL and EL50 values based on most average specific growth rates were 1.0 mg/L and 1 to 3 mg/L, respectively. The % growth inhibition, based on average specific growth rate, in the treated algal cultures as compared to the control ranged from 7.1 to 270%. Signs of phytoxicity include a reduction in growth rate (Shell, 1994).

In two reliable supporting algae toxicity studies (Selenastrum capricornutum) for two different kerosines products (Exxon, 1995h, 1995i) tested using the WAF methodology and following OECD Guideline 201, the 96 -hour EL50 (loading rate resulting in 50% decrease in growth of algae) varied between 5.0 to 6.2 mg/L (based on both area under the growth curve and average specific growth rates). The NOEL for these tests varied between 0.4 and 6.2 mg/L. In another reliable supporting algae toxicity study (Raphidocelis subcapitata) for hydrodesulfurised kerosine (Shell, 1995) was tested using WAF methodology, the 72 -hour EL50 was 10 to 30 mg/L WAF (based on both area under the growth curve and average specific growth rates). The NOEL was 10 mg/L. In another supporting algae toxicity study testing sweetened kerosine (Exxon, 1995g), on Selenastrum capricornutum, the 72-hour EL50 was determined to be 3.7 mg/L.