Assessing bioaccessibility and bioavailability of chlorinated organophosphorus flame retardants in sediments

The distribution of chlorinated organophosphate flame retardants (OPFRs) in sediments has been well documented, but the study about their bioavailability remains lacking. This study investigated the applicability of solid phase microextraction (SPME) fiber and Tenax extraction to predict the bioavailability of two chlorinated OPFRs: tri(2-chloroisopropyl) phosphate and tri(1,3-dichloro-2-isopropyl) phosphate, in sediments. Our results showed that both SPME fiber and Tenax extracted concentrations correlated significantly with the measured concentrations in the aquatic worm (Lumbriculus variegatus). We also measured the Tenax extracted concentrations at 6 and 24 h, and a strong linear relationship between these two time durations was found. In addition, the 6-h Tenax extracted concentrations also significantly correlated with the SPME fiber extracted concentrations, and the Tenax extracted concentrations were much higher than the SPME fiber extracted concentrations. These results demonstrate the efficiency of SPME and Tenax extraction methods to predict the bioavailability of chlorinated OPFRs in sediments, and it was found that the Tenax extraction is more promising than the SPME extraction.