Sensitivity assessment of Biomphalaria glabrata (SAY, 1818) using reference substance sodium dodecyl sulfate for ecotoxicological analyzes.

Abstract

Sodium dodecyl sulfate (SDS) is a surfactant used and recommended by regulatory agencies as a reference substance in ecotoxicological analyzes. In this work, acute toxicity assays were performed with adults and embryos of the freshwater snail Biomphalaria glabrata, an endemic organism with environmental and public health importance, to evaluate the effects of the surfactant and establish a sensitivity control chart. The organisms were exposed to SDS for 24 h to a range of concentrations, as well as a control group. Six assays were performed to establish the control chart for adults (with a median LC50 of 36.87 mg L-1) and differential sensitivity was observed at each embryonic stage (EC50 = blastulae 33.03, gastrulae 35.03, trochophore 39.71 and veliger 72.55 mg L-1). The following behavioral responses were observed in exposed adult snails: release of hemolymph and mucus, body outside the shell, and penile overexposure. Embryos at the blastulae and gastrulae stages were more sensitive, and teratogenic effects were accentuated in the trochophore stage. The difference in results obtained between adults and embryos underscore the importance of carrying out analyzes at different developmental stages. The serial assays established with SDS for B. glabrata demonstrated efficiency and constancy conditions in the assays with good laboratory practice standards. The wide distribution of Biomphalaria species in several countries, their easy maintenance and cultivation in the laboratory, in addition to ecological importance, make them economical alternatives for ecotoxicological assays.