Assessment of Human Exposure to Traditional and Novel Organophosphate Esters via Multiple Personal Matrices.

Herein, 16 traditional and 13 novel organophosphate esters (OPEs) in skin wipes, personal PM2.5, sputum, and nails (fingernails and toenails) and 7 OPE metabolites in urine synchronously obtained from 64 college students were analyzed. Similar compositional profiles of the OPEs were found in skin wipes and nails and in personal PM2.5 and induced sputum. Significant correlations were observed between the concentrations of high-lipophilicity low-volatility OPEs in skin wipes and nails and between the concentrations of high-volatility low-lipophilicity OPEs in personal PM2.5 and sputum. These results imply that OPEs in fingernails and toenails may mainly come from external sources rather than internal exposure, and human nails and sputum can be used as indicators of human exposure to OPEs. A comparison between the daily exposure doses of the OPEs in personal PM2.5 and sputum shows that more volatile compounds may have higher inhalation bioavailability, which should be considered to improve the accuracy of inhalation exposure assessments. According to comprehensive external and internal exposure assessment, dermal absorption may be a more dominant pathway than inhalation, and skin wipes may be the best representative environmental matrix of human exposure to OPEs.

Global patterns of human exposure to flame retardants indoors.

To fill the knowledge gaps regarding the global patterns of human exposure to flame retardants (FRs) (i.e., brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs)), data on the levels and distributions of FRs in external and internal exposure mediums, including indoor dust, indoor air, skin wipe, serum and urine, were summarized and analysed. Comparatively, FR levels were relatively higher in developed regions in all mediums, and significant positive correlations between FR contamination and economic development level were observed in indoor dust and air. Over time, the concentration of BFRs showed a slightly decreasing trend in all mediums worldwide, whereas OPFRs represented an upward tendency in some regions (e.g., the USA and China). The occurrence levels of FRs and their metabolites in all external and internal media were generally correlated, implying a mutual indicative role among them. Dermal absorption generally contributed >60% of the total exposure of most FR monomers, and dust ingestion was dominant for several low volatile compounds, while inhalation was found to be negligible. The high-risk FR monomers (BDE-47, BDE-99 and TCIPP) identified by external exposure assessment showed similarity to the major FRs or metabolites observed in internal exposure mediums, suggesting the feasibility of using these methods to characterize human exposure and the contribution of indoor exposure to the human burden of FRs. This review highlights the significant importance of exposure assessment based on multiple mediums for future studies.

Distribution, sedimentary record, and persistence of microplastics in the Pearl River catchment, China.

Microplastics (MPs) in the environment have become an issue worldwide. However, data about MPs in freshwater systems are still limited so far. This study investigated sources, fate, and seasonal and spatial distribution of MPs in the main stream Pearl River and its tributaries, as well as in the Pearl River Estuary (PRE), China. MPs were widely detected in the river water, river bed sediment, and estuarine sediment, with abundances of 0.57 ±â€¯0.71 items L-1, 685 ±â€¯342 items kg-1 dry weight (dw), and 258 ±â€¯133 items kg-1 dw, respectively. Sheet, fragmental, and fibrous polyethylene, polypropylene, and ethylene-propylene copolymers were predominant, suggesting that MPs in the Pearl River catchment be mainly derived from fragmentation of discarded plastic wastes. In addition, municipal wastewater was also an important MPs source, especially for polyethylene terephthalate (PET) fibers. Polymers of higher density, such as PET and polyvinyl alcohol were relatively more abundant in the sediment than in the river water, especially in the estuarine sediment. Upward increase of the MP abundance was observed in the sedimentary core, probably indicating increasing release of plastic wastes due to growing production and uses of plastic products. On the other hand, percentage of finer MPs increased with increasing depth. The results revealed persistence and potential downward dispersion of the fine MPs. The MPs abundance was positively related with population density and gross domestic product, demonstrating impacts of human activities and economic development on the MPs contamination. Higher MPs abundance was detected in dry season than in wet season in the river water, suggesting dilution effect of precipitation. It's estimated that 15963 tons of MPs could be released annually into the PRE from the main stream Pearl River and its tributaries.