Bioaccumulation and Trophic Transfer of Organophosphate Flame Retardants and Their Metabolites in the Estuarine Food Web of the Pearl River, China

The accumulation and trophodynamics of organo-phosphate flame retardants (OPFRs) and their metabolites were investigated in the estuarine food web of the Pearl River, China. The mean n-expressionry sumexpressiontion OPFR concentration among the investigated species increased in the following order: fish [431 +/- 346 ng/g lipid weight (lw)] < snail (1310 +/- 621 ng/g lw) < shrimp (1581 +/- 1134 ng/g lw) < crab (1744 +/- 1397 ng/g lw). The di-alkyl phosphates (DAPs) of di-(n-butyl) phosphate (DNBP), bis(2-butoxyethyl) phosphate (BBOEP), and diphenyl phosphate (DPHP) were the most abundant metabolites, with concentrations same as or even higher than their corresponding parent compounds. The log bioaccumulation factors for most OPFRs were lower than 3.70, and significant biomagnification was only found for trisphenyl phosphate [TPHP, with the trophic magnification factors (TMFs) > 1]. The TMFs of OPFRs, except for TPHP and tributyl phosphate had a positive correlation with lipophilicity (log KOW, p < 0.05) and a negative correlation with the biotransformation rate (log KM, p < 0.05). The mean TMF > 1 was observed for all of the OPFR metabolites based on the bootstrap regression method. The pseudo-biomagnification of OPFR metabolites might be attributed to the biotransformation of OPFRs in organisms at high trophic levels.

Automated summary

The accumulation and trophodynamics of organo-phosphate flame retardants (OPFRs) and their metabolites were studied in the Pearl River estuarine food web of China. The concentration of OPFRs varied among different species, with the highest in crabs and the lowest in fish. The most abundant metabolites were di-alkyl phosphates (DAPs), with concentrations higher than or equal to their parent compounds.