Assessment of organophosphate flame retardants in surface water and sediment from a freshwater environment (Yangtze River, China).

Organophosphate flame retardants (OPFRs) have been detected in the surface water, suspended sediments, and river sediments from the Yangtze River in China. A modified polar organic chemical integrative sampler (m-POCIS) was successfully used to quantify the OPFR concentrations in surface water. The OPFR concentrations estimated by the field m-POCIS at six sampling locations ranged from 8.99 to 112.45 ng/L with an average concentration of 47.04 ng/L. The OPFR concentrations in suspended sediments were related to the sediment particle size distribution. Chlorinated and alkyl OPFRs were the principle compounds in sediments, especially tris(2-chloroisopropyl) phosphate (TCPP) with concentrations of 3.37-29.65 ng/g. The relationship between the OPFR concentrations and total organic carbon (TOC) contents in sediments was examined. The results suggested that the OPFR concentrations were significantly correlated with the TOC contents. The primary OPFR transport mechanism in a freshwater environment occurs in surface water rather than sediment. This was evaluated by the logKow and field sediment-water partition coefficient (logKoc) values between the sediment and water. Finally, the various distributions and transport of OPFRs at the sampling sites indicated that human activities, agricultural production, and wastewater effluents from sewage plants have an important effect on the OPFR levels in a freshwater environment.

In situ calibration of polar organic chemical integrative samplers to monitor organophosphate flame retardants in river water using polyethersulfone membranes with performance reference compounds.

Passive sampler is an innovative way of monitoring chemicals in different environmental. A modified polar organic chemical integrative sampler (m-POCIS) with a performance reference compound (PRC) was used to evaluate the concentrations of 8 organophosphate flame retardants (OPFRs) under field conditions. The m-POCIS was deployed for 15days under laboratory conditions and 21days under in situ conditions to determine the concentrations of OPFRs. The analytes were trapped in the sorbent and the microporous polyethersulfone (PES) membrane of the m-POCIS. Sampling rates (Rs) were determined for the studied compounds and ranged from 0.02±0.0003L/d (triphenylphosphine oxide, TPPO) to 0.24±0.021L/d (tripropyl phosphate, TPrP) in the laboratory. The membranes accumulation increased with usage and was correlated to the logKow. Among the tested compounds, tripentylphosphate (TPeP) and triphenylphosphate (TPhP) had the highest logKow values and were mostly detected in the membranes. This behavior resulted in a lag-phase, which was measured by extrapolating the data from the last third of the uptake phase (quasilinear) to the x-axis using a linear regression, before the compounds transferred into the sorbent. TPhP was the only compound with a lag-phase of 3.9days during the 15days experiment. Deuteratedtributyl phosphate (TBP-d27) and desisopropyl atrazine-d5 (DIA-d5) were identified through specific experiments as potential PRC. The results from the PRC calibrations suggested that DIA-d5 (ke (in situ)=0.075±0.0048day-1) can be used as a PRC for the evaluation of OPFRs using m-POCISs. The time-weighted average (TWA) concentrations estimated by the m-POCIS with or without a PRC were significantly correlated with the corresponding values determined from the grab samples. After the PRC calibration, the TWA concentrations of the tested OPFRs in an aquatic environment were lower than those estimated using the laboratory sampling rates (Rs). The m-POCIS with a PRC correction was a suitable tool for estimating OPFRs TWA concentrations in the Yangtze River.

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.

Aquatic passive sampling of perfluorinated chemicals with polar organic chemical integrative sampler and environmental factors affecting sampling rate.

A modified polar organic chemical integrative sampler (POCIS) could provide a convenient way of monitoring perfluorinated chemicals (PFCs) in water. In the present study, the modified POCIS was calibrated to monitor PFCs. The effects of water temperature, pH, and dissolved organic matter (DOM) on the sampling rate (R s) of PFCs were evaluated with a static renewal system. During laboratory validation over a 14-day period, the uptake kinetics of PFCs was linear with the POCIS. DOM and water temperature slightly influenced POCIS uptake rates, which is in consistent with the theory for uptake into POCIS. Therefore, within a narrow span of DOM and water temperatures, it was unnecessary to adjust the R s value for POCIS. Laboratory experiments were conducted with water over pH ranges of 3, 7, and 9. The R s values declined significantly with pH increase for PFCs. Although pH affected the uptake of PFCs, the effect was less than twofold. Application of the R s value to analyze PFCs with POCIS deployed in the field provided similar concentrations obtained from grab samples.