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Total reflection X-ray fluorescence has advantages of simultaneous multi-element detection, potential of trace analysis, etc. However, overlapping effects may lead to loss of accuracy or even faulty results in practical quantitative multi-element analysis, especially for trace elements in environmental samples. Conventional approaches consider only partial overlapping effects and are difficult to be generalized. Thus, an intelligent quantitative multi-element determination method is proposed. With a scalable spectral decomposition framework, quantification becomes approximating measured spectra with characteristic curves of possible elements. Particle swarm optimization is used to solve the problem with a heuristic scheme. Trace elements, including K, Cr, Mn, Fe, Co, Ni, As and Pb, are measured simultaneously on the established TXRF analysis platform. Experiments verify that high measurement precision and computational efficiency can both be obtained by adopting the proposed method.

Environmental risk prevention has been included in China's national environmental protection plan of the Twelve Five-year (2011-2015). The establishment of environmental risk management system is an important issue for accident prevention and risk control. With reference to the general guidance on risk management programs for chemical accident prevention of the US EPA, the main procedures of environmental risk management and risk level classification for chemical facilities in urban area were proposed. The proposed method was applied to the identification of risks of chemical facilities in Luoyang city, Henan Province, and the facilities were classified into three risk levels. The results showed that five facilities were of low risk, two of middle risk and seven of high risk among 60 facilities in the main urban area, accounting for 8.3%, 3.3% and 11.7% of the total. Different management measures were taken into account for the facilities with different risk levels. It is suggested that for the facilities with high risks, besides the daily risk management, the environmental risk receptor investigation, the public participation and the preparation of emergency response plans should be strengthened, which were helpful for the prevention of environmental pollution accidents and the reduction of environmental hazards.

Based on environment statistics data from 1992–2008, the changing tendency, types, causes and directly economic losses of national environmental pollution accidents were analyzed, and the high risk areas of water and air pollution accidents were studied by using Supermap. The results indicated that the number of annual environmental accidents was maximally 3001 times in 1994 and minimally 462 times in 2007 during 17 years. The frequency of pollution accidents decreased especially after 2006. Water and air pollution accidents are main types of all accidents, accounting for 54.3% and 34.2% respectively. Pollution accident occurred mainly due to production safety accidents and chemical transportation accidents, accounting for 30.8% and 26.9% respectively. The high risk areas of pollution accidents centralized in southeast and middle parts of China. Water and air pollution accidents occurred frequently in Guangxi, Hunan, Sichuan, while water pollution accidents occurred frequently Zhejiang, Jiangsu and Guangdong. The directly economic losses of the accidents mainly came from the major level accidents and water pollution accidents. Finally proposals for accident prevention and management were given.

The hexavalent chromium (Cr(VI)) removal by zero-valent iron (Fe0) was investigated under various groundwater geochemistry conditions though batch experiments. The results showed that the collective influences of humic acid, HCO 3 −, and Ca2+ on the reactivity of zero-valent iron for Cr(VI) removal were different from their individual impacts. The sole presence of humic acid did not show a significant impact to Cr(VI) reduction, while HCO 3 − exerted a great buffering effect on the reaction. When humic acid and Ca2+ co-present in the solution, the pH increased slowly but Cr(VI) removed rapidly. In contrast, pH remained at below 8.0 and 7.8 and Cr(VI) removal rate were 97.77% and 98.82% at the 60mins in solutions containing 2 mM and 6 mM of HCO 3 −, respectively. These experimental results were also demonstrated by a pseudo-first-order model followed.