NEW PUBLICATION: A GLOBAL FRAMEWORK TO MODEL SPATIAL ECOSYSTEMS EXPOSURE TO HOME AND PERSONAL CARE CHEMICALS IN ASIA

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This paper analyzes ecosystems spatial exposure to home and personal care (HPC) chemicals, accounting for market data, environmental processes in hydrological water basins networks, including multi-media fate and transport. We present a global modeling framework built on ScenAT (spatial scenarios of emission), SimpleTreat (sludge treatment plants), and Pangea (spatial multimedia fate and transport of chemicals), that we apply over Asia to four chemicals selected to cover a variety of applications, volumes of production and emission, and physico-chemical and environmental fate properties: the anionic surfactant Linear alkylbenzene sulphonate (LAS), the antimicrobial triclosan (TCS), the personal care preservative methyl paraben, and the emollient decamethylcyclopentasiloxane (D5). We present maps of predicted environmental concentrations (PECs), and compare them with monitored values, over the entire Asia and per river. LAS emission levels and PECs are two to three orders of magnitude greater than for other substances, yet the literature about monitored levels of LAS in Asia is very limited. We observe a good agreement for TCS in fresh water (Pearson r = 0.82, for 253 monitored values covering 12 streams), a moderate agreement in general, and a significant disagreement for methyl paraben in sediments. This points at the need for more specific/spatial information on both chemical/hydrological parameters (DT50water, DT50sediments, Koc, foc, TSS) and monitoring sites (e.g. spatial/temporal design, site medium parameters), especially for evaluating PECs in sediments in Asian streams. We illustrate the relevance of local evaluations for short-lived substances in fresh water (LAS, methyl paraben), and their inadequacy for longer lived-substances (TCS, D5). This framework constitutes a milestone towards higher tier modeling approaches for identifying hotspots, and linking large-scale fate modeling with (sub) catchment-scale ecological scenarios; a major limitation encountered comes from the discrepancy between streams routed on a gridded, 0.5° x 0.5° global hydrological network and actual locations of streams and monitoring sites.

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