Uptake, Tissue Distribution and Elimination of 8:2 Polyfluoroalkyl Phosphate Diesters in Mytilus galloprovincialis.

Although the distribution of 8:2 polyfluoroalkyl phosphate diester (8:2 diPAP) in aquatic environments has been reported, details on its uptake, tissue specificity and elimination in bivalve mollusks remain to be clarified. The present study is the first report on the accumulation and elimination of 8:2 diPAP in mussels (Mytilus galloprovincialis). The tissue specific accumulation and depuration of 8:2 diPAP and its metabolites were investigated via semi-static seawater exposure (8:2 diPAP at nominal concentration of 10 μg/L), through water-borne exposure with static daily renewal over a 72 h exposure period and 360 h depuration period. The digestive gland was found to be the target organ where accumulation and biotransformation primarily occur. The bioaccumulation factor values (mL/g dw) in different organs were in the following order: digestive gland (1249) > adductor muscle (315) > gills (289) > gonad (82.9) > mantle (33.0). Moreover, the distribution of 8:2 diPAP among tissues may be related to the total protein content. The 8:2 diPAP tended to be excreted in feces. The 8:2 fluorotelomer carboxylic acid (8:2 FTCA), 8:2 fluorotelomer unsaturated carboxylic acid (8:2 FTUCA), 7:3 fluorotelomer carboxylic acid (7:3 FTCA), perfluorooctanoic acid (PFOA) and perfluoroheptanoic acid (PFHpA) were detected and quantified as phase I metabolites, and the concentration of all phase I metabolites relative to the 8:2 diPAP concentration (72 h) was 0.304 mol%. A phase II metabolite, 8:2 fluorotelomer alcohol conjugated with sulfate, was detected but not quantitated in the digestive gland. Biotransformation pathway of 8:2 diPAP in M. galloprovincialis was proposed on the basis of the results obtained in the present study and previous studies. These findings improve the understanding of the accumulation of perfluorocarboxylic acids in bivalve mollusks. This article is protected by copyright. All rights reserved.