Temporal and Spatial Distribution of Arsenic Speciation in Sediments of Plateau Lakeside Wetland and Their Relations to Environmental Factors

摘要

This paper chose the surface sediments of lakeside wetland from southern Yangzonghai as the research object, studied the sediment contents of total arsenic (TAs) and arsenic fractions (acid soluble arsenic-F1, reducible arsenic-F2, oxidable arsenic-F3 and residual arsenic-F4) of different seasons and environmental parameters (Water soluble total phosphorus -WDTP, Sediment Available Phosphorus-SDTP, Organic matter-OM, Sediment pH, Dissolved oxygen-DO, Oxidation-reduction potential-Eh, Conductivity-Ec, Sediment particle size-clay, silt and sand), and analysis spatial and seasonal distribution characteristics of arsenic in relation to environmental parameters by using statistics. The results are shown as follows. (1) There is little variation in the TAs content of the lakeside wetland deposits, but the second belt transect was as high as 89.82 mg/kg in July, and the sediments in some areas are still facing environmental risk. Relatively levels of TAs were observed during winter compared to summer, and the seasonal difference of TAs distribution was not pronounced. In a word, the content of TAs is steady. (2) The most arsenic fractions in sediments is residue and the sum of the valid states is higher than the residue state. Meanwhile Fl, F3 present differences in different seasons, and environmental parameters have a certain influence on its. Lakeside wetland's environment could face a secondary pollution in the future; (3) The correlation analysis, redundancy analysis and factor analysis illustrate that environmental factors which affect arsenic forms are different in the shore area, lake area and central area, S-DTP, OM, pH, these three are the key factor of the lakeside wetland arsenic changes.