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Due to the lack of monitoring systems and water purification facilities, residents in western China may face the risk of drinking water pollution. Therefore, 673 samples were collected from Lhasa's agricultural and pastoral areas to reveal the status quo of drinking water. We used inductively coupled plasma-mass spectrometry to determine trace elements concentrations for water quality appraisal, source apportionment, and health risk assessment. The results indicate that concentrations of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ba, and Pb are below the guidelines, while As concentrations in a few samples exceed the standard. All samples were classified into "excellent water" for drinking purpose based on Entropy-weighted water quality index. Thereafter by principal component analysis, three potential sources of trace elements were extracted, including natural, anthropogenic, and mining activities. It is worth noting that geotherm and mining exploitation does not threaten drinking water safety. Finally, health risks were assessed using Monte Carlo technique. We found that the 95th percentiles of hazard index are 1.80, 0.80, and 0.79 for children, teenagers, and adults, indicating a non-carcinogenic risk for children, but no risks for the latter two age groups. In contrast, the probabilities of unacceptable cautionary risk are 7.15, 2.95 and 0.69% through exposure to Cr, Ni, As, and Cd for adults, children, and teenagers. Sensitivity analyses reveal As concentration and ingestion rate are most influential factors to health risk. Hence, local governments should pay more attention to monitoring and removal of As in the drinking water. [ABSTRACT FROM AUTHOR]

We tested six kinds of commercially available baby products containing nano-silver and divided them into two categories: baby food containers and baby oral care products, according to usage. We measured the total mass of silver, particle size, particle number concentration and the mobility under different simulated conditions. The total mass of silver in baby products and migration solutions was quantified by ICP-MS analysis, and the size of the migrated particles was investigated by single particle ICP-MS and transmission electron microscopy-energy dispersive spectrometer. Nano-silver has different migration behaviour in different materials, and the total mass of silver released in 3% acetic acid was generally highest for plastic material, while highest in 10% ethanol for silicone material. For baby food containers and baby oral care products, the total amount of silver in the migration solutions varied from 2.98 to 126.46 ng/dm2 and from 2.01 to 2.83 ng/g, respectively. The research shows that the use of baby products containing silver may expose babies to silver nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract Using a probabilistic material flow analysis model, we investigate the mass balance and occurrence of nano-silver in the environment of Hunan, renowned as "the home to non-ferrous metals" in China. The model builds on China-specific production and environmental information and incorporates sulfidation of nano-silver in urban wastewater treatment systems. We predict that the bulk of nano-silver (>90%), primarily originating from production and consumption of nano-silver products, ends up in sewage treatment plants (STPs, 5.3 t/a), followed by the landfill (4.7 t/a). More than 99% of nano-silver in STPs reacts with sulfide and thus does not appear in effluents. Direct release of nano-silver from production and consumption is identified as the dominant source of nano-silver in the environment, most of which enters surface water (0.71 t/a). As such, regulation of direct emissions from production and consumption of nano-silver products can be of priority for local environmental management. The modeled regional concentrations (modes) of nano-silver are 0.9 ng/L in surface water, 20 ng/kg in soil, 6.9 μg/kg in sediment, and negligible in the air, which agree well with measurements in the modeled region. Based on the modeled concentrations, we calculate that the risk characterization ratio is <1 in the air, surface water and soil, which means that nano-silver currently poses no risk to organisms living in these environmental compartments. Graphical abstract Unlabelled Image Highlights • Considering the vulcanization of nano-silver in urban wastewater treatment system • China's special conditions and data are applied to PMFA model. • We predicted nano-silver exposure and environmental concentration in Hunan, China. • We discuss the main sources of nano-silver in environmental media. [ABSTRACT FROM AUTHOR]