A passive sampling method for assessing the occurrence and risk of organophosphate flame retardants in aquatic environments.

A modified polar organic chemical integrative sampler (m-POCIS) was used to determine the occurrence of and risk posed by organophosphate flame retardants (OPFRs) in the Yangtze River in Nanjing. Laboratory calibrations were performed to determine sampling rates (Rs) in different situations. Rs values increased with the flow rate, but the effect of dissolved organic matter (DOM) on Rs was relatively small. The validation of Rs in the m-POCIS for 15 days at the Yangtze River in 2015 showed that the Rs values for most of the test compounds are considerably larger than those obtained in the laboratory. The aqueous concentrations of OPFRs were estimated by using Rs values obtained in the field. OPFRs were widely distributed in the Yangtze River, with total concentrations as determined by the m-POCIS ranging from 44.95 ng/L to 118.38 ng/L. These suggest their widespread use and persistence in the river. This study also provided a protocol for the assessment of risk posed by OPFRs. It showed that tripentyl phosphate (TPeP) could pose medium risk to daphnia in the Yangtze River.