Exposure to single and binary mixtures of fullerenes and triclosan: Reproductive and behavioral effects in the freshwater snail Radix balthica

Abstract

Emerging pollutants occur in complex mixtures in rivers and have the potential to interact with freshwater organisms. The chronic effects of nominal exposure to 3 μg/L of fullerenes (C60) and 1 μg/L of triclosan (TCS) alone and in a binary mixture, were evaluated using the freshwater snail Radix balthica. Pollutants accumulation, reproductive output and feeding behavior were selected as sublethal endpoints. After 21 days of exposure, we did not observe interactive effects between TCS and C60 on the studied endpoints, except for the accumulation of C60 in R. balthica in TCS + C60 treatment, which was lower than when the fullerenes were alone. Neither TCS nor C60 caused significant effects on reproduction, expressed as number of eggs per individual, but an increase in the clutch size was observed in treatments with TCS at the third week of exposure, independently of the presence of C60 (16.15 ± 1.67 and 18.9 ± 4.01 eggs/egg mass in TCS and TCS + C60 treatments, respectively, vs. 13.17 ± 4.01 in control). The presence of C60 significantly enhanced the grazing activity of R. balthica during the first seven days (4.95 ± 1.35 and 3.91 ± 0.59% of the area grazed per individual in C60 and TCS + C60 treatments, respectively, vs 2.6 ± 0.39% in control). The accumulation of TCS was quite similar in treatments where this pollutant was present (BAF ≈ 1007 L/kg d.w.); however, the accumulation of C60 was higher when the nanoparticles were alone (BAF = 254.88 L/kg d.w.) than when it was in the binary mixture (BAF = 7.79 L/kg d.w). Overall, although TCS has been listed as an endocrine disrupter compound, no significant effects on reproduction were observed in the assayed conditions. Regarding C60, the limited effects on feeding activity and the low BAF obtained in this experiment indicate that fullerenes do not have ecological consequences of relevance at the studied environmental concentrations in freshwater snails