The Environmental Emissions And Risk Assessment Of Nano-silver Particles Based On Life Cycle

Engineering silver nanoparticles(Ag NPs) are increasingly used because of their unique properties, however, it is inevitable that Ag NPs are released into the environment during their manufacture, use and disposal, which has been identified resulting in hazard to human beings and the ecosystem. At present, most of research are focusing on preparation, application, toxicity of Ag NPs while very little is known about their exposure concentration, migration and transformation due to lacking of available practical analytical methods and instability of Ag NPs. Based on life cycle theory, using material flow analysis, the potential environmental release and migration of Ag NPs were modeled in their every stage in eastern region, central region and western region in China in 2012. Then the potential environmental risk in surface water was evaluated.Firstly, the estimation methods of nanomaterials production were summarized. According to the report of global production Ag NPs, using the GDP and the population of developed and industrial countries models, the production volumes of Ag NPs in China in 2012 were estimated about 81.0t, 56.9t and 65.3t in 2012, respectively. Meanwhile, main 34 enterprises in China were investigated, and the production volumes of Ag NPs was about 44.6t.Secondly, due to the variety and economic gaps of different areas in China, according to the GDP model, the volumes of Ag NPs in the eastern, central and western regions were obtained about 24.8-45.1t, 11.0-19.9t, 8.8-16.0t in 2012. Then, on the basis of a Chinese market report and similar release paths of Ag NPs from products, the volumes of Ag NPs were al ocated into main seven kinds of products, which were textiles, cosmetics, paints, plastics, medical, glass and ceramics, metal and electronics products accounting for 15.9%, 15.9%, 10.2%, 23.3%, 17.7%, 12.4% and 4.6%, respectively.Thirdly, the release of Ag NPs during their production, manufacture and use of various products was analyzed according to the properties of Ag NPs and environmental conditions and waste disposal in China. Then, the volumes of Ag NPs released into surface water, soil, air, and landfill in different regions was evaluated quantitively, which were 2.23-4.05t、3.19-5.80t、0.011-0.019t、13.11-23.84 t in the eastern region, 0.99-1.79 t, 1.41-2.57 t, 0.0046-0.0084 t, 5.80-10.53 t in the central region, 0.79-1.44 t, 1.13-2.06 t, 0.0038-0.0067 t, 4.65-8.45 t in the western region.At last, the concentrations of Ag NPs in surface water, soil, air, and landfill were obtained according to the environmental data of various regions, which were about 3.78-6.86ng/L, 18.95-34.41ng/kg, 0.0098-0.02ng/m3, 14.41-25.98μg/kg in eastern region, 1.57-2.85ng/L, 4.78-8.68ng/kg, 0.0028-0.005ng/m3 in the central region, 12.96-23.53μg/kg, 0.58-1.05ng/L, 1.81-3.29ng/kg, 0.0005-0.001ng/m3, 13.26-24.08μg/kg. Meanwhile, based on the ecological toxicology data of Ag NPs, the potential environmental risk of Ag NPs in the surface water were 0.17-0.22 in eastern region. It was showed that the production of Ag NPs, properties of Ag NPs and environmental conditions were the key factors to effect the accuracy of the results according to the single factor sensitivity analysis. This research could provide optional method for the envirionmental exposure and the environmental risk assessment of nanomaterials, which is important in the sustainable development of nanomaterials.