Laboratory Evaluation of the Toxicity of Perfluorooctane Sulfonate (PFOS) on Selenastrum capricornutum , Chlorella vulgaris , Lemna gibba , Daphnia magna , and Daphnia pulicaria

Abstract

Perfluorooctane sulfonate (PFOS) is an anthropogenic compound found in trace amounts in many environmental compartments far from areas of production. This, along with the highly persistent nature of PFOS, presents a concern for possible effects in aquatic ecosystems. The objective of this study was to determine the toxicity of PFOS in representative freshwater organisms. Toxicity testing using standard laboratory protocols was performed on the green algae Selenastrum capricornutum and Chlorella vulgaris, the floating macrophyte Lemna gibba, and the invertebrates Daphnia magna and Daphnia pulicaria. No observable effect concentration (NOEC) values were generated from the most sensitive endpoints for all organisms. Autotroph inhibition of growth NOEC values were 5.3, 8.2, and 6.6 mg/L for S. capricornutum, C. vulgaris, and L. gibba, respectively. The 48-h immobility NOEC values for D. magna and D. pulicaria were 0.8 and 13.6 mg/L, respectively. In comparison to immobility, the 21-day lethality NOEC for D. magna was 5.3 mg/L. Based on effect (immobility) values, the most sensitive of all test organisms was D. magna. The most sensitive organism based on 50% inhibition of growth (IC(50)) was L. gibba, with an IC(50) value of 31.1 mg/L determined from wet weight. This is 4.3 times less than the LC(50) for D. pulicaria, which was 134 mg/L. Significant adverse effects (p < or = 0.05) were observed for all organisms in concentrations >134 mg/L. The results indicate that under laboratory conditions PFOS is acutely toxic to freshwater organisms at concentrations at or near 100 mg/L. Based on known environmental concentrations of PFOS, which occur in the low ng/L to low microg/L range, there is no apparent risk to freshwater systems. However, further work is required to investigate long-term effects in these and other freshwater organisms.

Chronic Effects of Perfluorooctane Sulfonate and Ammonium Perfluorooctanoate on Biochemical Parameters, Survival and Reproduction of Daphnia magna

“…19,30) The 21-d LC 50 and survival NOEC values of Daphnia magna exposed to PFOA in this study are greater than 100 mg/l and are similar to those reported by Colombo et al 11) In their recently published study, the EC 50 and survival NOEC of Daphnia magna were reported to be greater than 88.6 mg/l after 21 days exposure. Compared with published data on the chronic toxicity of PFOS, the 21-d survival NOEC of 5 mg/l found for Daphnia magna in this study is similar to the value of 5.3 mg/l for Daphnia magna in the study of Boudreau et al, 16) but the 21-d LC 50 of 9.1 mg/l found for Daphnia magna in this study is lower than the 21-d LC 50 of 42.9 mg/l for Daphnia magna reported in the same study. 16) In addition, MacDonald et al reported a 10-d survival LC 50 of 0.045 mg/l for the aquatic midge (Chironomous tentans).…”

“…Compared with published data on the chronic toxicity of PFOS, the 21-d survival NOEC of 5 mg/l found for Daphnia magna in this study is similar to the value of 5.3 mg/l for Daphnia magna in the study of Boudreau et al, 16) but the 21-d LC 50 of 9.1 mg/l found for Daphnia magna in this study is lower than the 21-d LC 50 of 42.9 mg/l for Daphnia magna reported in the same study. 16) In addition, MacDonald et al reported a 10-d survival LC 50 of 0.045 mg/l for the aquatic midge (Chironomous tentans). 17) Although Daphnia magna is an important species for ecotoxicological study, it may not be a sensitive test species for PFOS or PFOA toxicity and some less common aquatic test species should be considered for chronic toxicity tests.…”

“…All stock solutions of testing chemicals were prepared in ASTM medium in using polymethyl pentene containers, because these two chemicals can be adsorbed onto glass surfaces. 16) Water solubility for PFOS was 550 mg/l at 24-25 • C 22) and for PFOA was 3400 mg/l at 25 • C. 23) In this study, stock solutions of PFOS and PFOA were 400 mg/l and 1000 mg/l, respectively. Based on the water solubility of test chemicals and previous acute toxicity results, nominal test concentrations were in the range of 0.5-20 mg/l for PFOS and 1-100 mg/l for PFOA.…”

“…13) Until now, only a few published studies have investigated the chronic sublethal effects of PFOS and PFOA on aquatic species; including fish, amphibian and aquatic invertebrate. 11,[14][15][16][17][18][19] The potential long-term ecotoxicological effects of PFOS and/or PFOA are needed to provide important information to adequately assess the ecological risk of PFOS and PFOA, which can be of great concern for aquatic fauna.…”

Acute toxicity of poly‐ and perfluorinated compounds to two cladocerans, Daphnia magna and Chydorus sphaericus

“…Among freshwater cladocerans, Daphnia magna is probably the most commonly used test organism in ecotoxicological studies. Some toxicity tests have been performed on cladocerans for perfluoro-octane sulfonic acid and perfluorooctanoic acid (PFOA) or their salts [15][16][17][18][19].…”