Assessing the Effects of a Diet of BPA Analogues-Contaminated Microalgae in the Clam Ruditapes philippinarum

In our previous study, we demonstrated that the microalgae Phaeodactylum tricornutum can bioaccumulate bisphenol A analogues. Since this microalgae species is part of the diet of marine filter-feeding organisms, such as bivalves, in this study we tested the hypothesis that a diet based on contaminated microalgae can exert negative effects on the clam Ruditapes philippinarum. Microalgae were exposed for 7 days to 300 ng/L of bisphenol AF, bisphenol F, and bisphenol S, alone or as a mixture, to allow bioaccumulation. Microalgae were then supplied as food to bivalves. After 7 and 14 days of diet, the effects of contaminated microalgae were evaluated on a battery of biomarkers measured in haemolymph/haemocyte, gills and digestive gland of clams. In addition, bioaccumulation of the three bisphenols was investigated in clams by UHPLC-HRMS. Results obtained demonstrated that total haemocyte count, and haemocyte proliferation were affected in clams fed with contaminated microalgae. The activity of some immune-related enzymes was also influenced. Significant alterations in antioxidant enzyme activities and oxidative damage to proteins and lipids were recorded in both gills and digestive gland from clams fed with contaminated microalgae. Alterations in epigenetic-involved enzyme activity were also found. No bioaccumulation of BPA analogues was detected in clam soft tissues. Overall, this study demonstrated that a diet of BPA analogues-contaminated microalgae can induce significant alterations of some important biological responses of R. philippinarum. To our knowledge this is the first study demonstrating the effects of ingestion of BPA analogues-contaminated microalgae in the clam R. philippinarum, suggesting a potential ecotoxicological risk for the marine food chain, at least at the first levels.