| 英文摘要 |
The aim of the “Arsenic and mercury pollution investigation of agricultural land and management strategies research program” was to collect domestic and foreign regulations, research reports and case studies related to As and Hg contaminations, apply material flow analysis to investigate the application of As and Hg in human economic activities and environmental release of As, develope the screening and investigation methods for As contaminations in farmland soils, groundwater and sediments, and conduct survey on (1)As from natural environment, (2) As-containing fertilizers. And to establish the source of arsenic contamination of agricultural soil pollution causes and determining program farmland soil arsenic determination procedures.
The investigation of As contamination from natural environment, after the preliminary survey, Xikou Township, Chiayi County have been selected. The result showed most of arsenic is held together with hydrous oxides of Fe and Al, and released by the iron-reducing process in aquifers. The vertical distribution of arsenic in aquifers is caused by the differences of reducing condictions of groundwater. Irrigating As-rich groundwater in farmland triggered the oxidation of Fe, Al and Mn, to hydrous oxides which sorbed As in soil, and decreased the bioavailability of As. As might release to soil solution caused by the water management of field.
The investigation of As contamination from As-contained compost showed non-maturity poultry compost contained more As than commercial compost. But the rate of non-maturity poultry compost didn’t cause the accumulation of As in farmland
Results of risk assessment showed eating soil gets the max exposure in various way, a relatively low exposure by inhalation and skin contact.
Calculating with the average soil As concentration and maximum reasonable concentration indicated that carcinogenic risk is significant, but non-carcinogenic risk is not. The average soil As concentration and maximum reasonable concentration in survey site are lower than domestic regulations. We suggested properly amending the regulations.
Combined with material flow analysis, results of survey sites investigation and the results of ecological and health risk assessment to make recommendations to the management strategies of As accumulation farmland soil in twofold: regulations level and technology level.
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