New compounds, old problems. The case of C6O4 - a substitute of PFOA - and its effects to the clam Ruditapes philippinarum

Abstract

C6O4 (difluoro{[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy}acetic acid) is a new surfactant and emulsifier used as a substitute of perfluorooctanoic acid (PFOA). Recently, C6O4 has been detected in aquatic environments, but, at present, no information concerning the effects of C6O4 on aquatic species, such as bivalves, are available in the literature. Therefore, in this study we evaluated for the first time the effects of C6O4 (0.1 and 1 µg/L) and PFOA (1 µg/L) to the clam Ruditapes philippinarum. Short-term (7 days) and long-term (21 days) exposures of clams to the two compounds were carried out and numerous biomarkers were measured in haemocytes/haemolymph, as well as in gills and digestive gland. The MANOVA analysis demonstrated statistically significant effects of the independent variables "treatment", "time" and "treatment-time interaction" on the whole dataset of biomarker responses. The two-way ANOVA analysis performed for each biomarker response indicated that the two compounds affected most of the cellular and tissue parameters measured. Despite preliminary, the results obtained suggested that C6O4 - similarly to PFOA - can affect both cellular and biochemical parameters of clams.

Keywords: Biomarker; Bivalve; Clam; PFAS alternative; Perfluoroalkyl ether carboxylic acids.