| Inductively coupled plasma mass spectrometry (ICP-MS) is an apparatus capable of analyzing a diverse range of elements with high sensitivity and rapid determination, which saw rapid development during the 1980s. Barnes predicted that ICP-MS would see rapid development in 21st-century. With 30 years of development, ICP-MS analysis technology has been widely applied to the fields of environmental health, pharmaceutical preparations, petrochemical industry, semiconductor industry, nuclear industry, geological survey, forensic identification, and other fields. Because of the unique advantages of ICP-MS, a growing interest of its application in the drinking water safety assessment is been seen within by the academic circle.Because the ICP-MS is kept confidential against our country and army, it is nece ssary to develop our own relevant ICP-MS technique. Using for water quality testing, ICP-MS can contribute to duly pre-warning, shortening the processing of surveying, monitoring, and choosing water source in either peacetime or wartime, and improving the treatment of contaminated drinking water, for the sake of a high class of health gu arantee. This research is supported by national major project for developing scientific instruments and equipment (2011YQ14015009). Following the project, this study will develop the application of importing ICP-MS in supervision on metals of drinking wa ter. The basic data will be accumulated, and used for the building of surveying method with mature instruments. This research will also value the testing effect of the instru ments and underlies the comparing analysis of them and importing instruments with si gnificant scientific meaning.The safety of drinking water not only relates to human health, but also relates to the stable development of the society. Water contamination by trace metals has driven considerable research for many decades. The contents of metal elements can influence human health. Some kinds of metal elements are necessary to human body, it may be beneficial to people’s health in case of ingesting low levels. And some metal elements is harmful to the body, these metals could further be bio-accumulated and even bio-magnified through the food chain, thereby posing potential harmful effects on human health and even the whole ecosystem.This study established detection methods of quantitative analysis and morphological analysis to analyze a variety of metallic elements in drinking water and sediment, experimenting with combinations of ICP-MS testing technology, and health risk assessment or BCR three-step extraction technology. Then, the safety evaluation of drinking water and sediment in some particular regions were studied.This thesis mainly contains the following parts:ICP-MS testing method of many kinds of metallic elements in drinking water was established in the first chapter of the thesis. The basic principle and structure of ICP-MS were introduced emphatically. The types of interference in the detection and the methods of their prevention were explored according to the principle. Finally, the detection methods of several metallic elements in drinking water and sediment were established by optimizing the instrument conditions. The experiment included the method of sample pretreatment, the selection of standard curve and preparation method, and data processing. It turned out that the methods are accurate and reliable, and this laid the foundation for the subsequent experimental study.The distribution regularity of metallic elements in drinking water of Tibetan area and Inner Mongolia region was studied in the second chapter. The contaminations of metal elements in drinking water in these two areas were determined, applying the established test methods of ICP-MS. The results indicated that, the average contaminations of 16 trace elements (Cr, Mn, Ni, Cu, Zn, As, Cd, Sb, Ba, Pb, Co, Be, V, Ti, Tl, Al) in drinking water collected in these two remote areas were within the allowable concentrations set by national agencies(GB5749-2006, GB3838-2002). A comparison revealed similarities and differences in the distribution of trace elements between the two study areas. Correlation analysis reflected significant positive correlations among most elements, suggesting that the elements were likely to have common sources.The research of health risk assessment was carried out in the third chapter. The total contaminations of 10 trace elements were detected by using the established test methods of ICP-MS. Human health risks were assessed using US EPA (1989) methodology, carcinogenic risks and non-carcinogenic risks were evaluated separately. The results indicated that the total carcinogenic risks in these two studied areas were both higher than the maximum allowed risk level set by most organizations (1×10-6), suggesting that the drinking water which meets the national standards could still be a threat to the health of local residents. The carcinogenic risks caused by Cd, As and Cr were much higher than the non-carcinogenic risks caused by Pb, Zn, Cu, Mn, Sb, Ba and Ni. Residents in both study areas were at risk of carcinogenic effects from exposure to Cr, which accounted for 80%～90% of the total health risks. Among the four population groups, the total health risk in descending order was infant> adult> teenager> the elderly. Infants were the most sensitive population and required dedicated attention. The results of probabilistic health risk assessment based on Monte-Carlo simulation revealed that the uncertainty of system parameters did not affect the decision-making of pollution prevention and control. Sensitivity analysis revealed that ingestion rate of water and concentration of metallic elements showed possibly high sensitivity to the health risks. These two parameters were the most sensitive and appeared positive sensitivity, suggesting that collecting local information of these two sensitive parameters to reduce their uncertainty can improve the reliability of results in further research.Chapter four selected the Miyun reservoir as the case, applying the established test methods of ICP-MS and BCR three-step extraction technology, the contaminations and morphological distribution of metal elements in drinking water and sediment were studied. The results indicated that, the average contaminations of 16 trace elements (Cr, Mn, Ni, Cu, Zn, As, Cd, Sb, Ba, Pb, Co, Be, V, Ti, Tl, Al) in drinking water collected in these two remote areas were within the allowable concentrations set by national agencies(GB5749-2006,GB3838-2002). Compared with the Tibetan Area and Inner Mongolia region, the contaminations of trace elements were significantly lower in Miyun reservoir, suggesting that, as the water source of drinking water in Beijing, the health risks induced by metal pollution may be lower in Miyun reservoir. Compared with the soil background values in Beijing, except for Pb, the average contaminations of other metals in sediment were obviously exceeded the values, suggesting that these metals showed the characteristics of accumulation in sediment, and Cr pollution may exist in some areas. Highly significant correlations were found among As, Ni, Sn, Bi and Cr, V, Ni, Cu,Co, indicating the likelihood of a common source. Correlations among Cd, Sb, Pb and other elements were not significant. This illustrated that these three elements may not have been influenced by external factors. The results of Morphological analysis indicated that, most of the metal elements showed that the content of acid extractable state is the lowest, and the content of residue state is the highest. As, Pb, Cd in some sampling sites may be easy to transfer into the water. Among all the studied metals, Ti is the most stable, and mainly exists in the form of residual state in all samples. It is hard to release into the water. |
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