Tissue-Specific Accumulation and Body Burden of Parabens and Their Metabolites in Small Cetaceans

Parabens have been of global concern due to their endocrine disrupting properties. However, few studies have reported tissue-specific distribution of parabens in wildlife. In this study, we measured parabens and their metabolites in organs and tissues (blubber, muscle, melon, stomach, kidney, liver, gonad, brain, uterus, and umbilical cord, total n = 94) of common dolphins (Delphinus capensis) and finless porpoises (Neophocaena asiaeorientalis), to investigate tissue-specific accumulation and body burden. Among the target compounds, methyl paraben (MeP) and para-hydroxybenzoic acid (4-HB) were detected in all organs. Compared to common dolphins, finless porpoises had significantly higher concentrations of MeP and 4-HB due to their near-shore habitat. Higher concentrations of MeP and 4-HB were found in the kidney, liver, and stomach than in other organs, indicating selective accumulation of parabens in certain organs. Significant correlations between MeP and 4-HB in liver/kidney suggested metabolic transformation of the former to the latter. Detection of parabens in brains, umbilical cords, and uteri suggests that these chemicals cross biological barriers such as the blood-brain and placental barriers. The body burdens of total parabens were in the ranges of 13000-90600 mu g and 19800-81500 mu g for common dolphins and finless porpoises, respectively.