Study on transformation of arsenic forms and ecological risk in soil under wetland habitats

Wei Rena, Y. G. Liua,b,c, G. Y. Yanga,b, and Y. Wanga

a College of Ecology and Soil & Water Conservation, Southwest Forestry University, China

b Research Center of Water Science and Engineering, Southwest Forestry University, China

c Research Center for Soil Contamination and Remediation, Southwest Forestry University, China

renweiswfc2017@163.com

Arsenic pollution poses a serious threat to the surface water environment safety of lakes, rivers, reservoirs and other places in many countries. Serious environmental arsenic pollution has occurred in countries such as Australia, the United States, Canada, Argentina and Bangladesh.In China, lakes/rivers such as Xiangjiang River, Bijiang River, Yangzong Lake and Datun Lake have been widely concerned about arsenic pollution. Although the arsenic pollution of some lakes has been effectively controlled over the years, studies have shown that the massive accumulation of arsenic in the sediments of lakes/river wetlands remains a significant potential risk that cannot be ignored. In general, under the influence of changes in soil pH and redox conditions, the conversion of As in soil between the easily soluble and insoluble arsenic compounds is a dynamic process. The occurrence of As in the sediment of lakeside wetland directly determines its toxic effects and ecological risks. The current sediment-water interface is the key area for the study of arsenic migration and transformation in the environment. It mainly focuses on the morphology and risk assessment of the in situ sediment As in rivers, lakes and offshore waters, and the effects of different media on the biochemical behavior of arsenic. Migration and transformation of arsenic in soil-rice systems. However, there are few reports on the dynamic changes of As morphology and the corresponding ecological risks in different arsenic-contaminated soils under wetland habitats. Therefore, A pot experiment was conducted to study the variation of the process of arsenic speciation transformation and assess the corresponding environmental risks by risk assessment coding (RAC) in soil with different treatments of exogenous arsenic (0, 50, 100, 200, 400 mg/kg) at different time (50, 100 and 200 d) by typical wetland plant Typha angustifolia L. in simulated wetland habitat. The results showed that the content of non-specific adsorption state As (F1) and the residue state As (F5) were decreasing continuously, and the crystal form of iron-aluminum oxide bound state As (F4) was increasing, from biologically effective to non-biologically effective. As the experimental time lengthens, the environmental risk of As in the soil shows a slight increase after the firstly increased, and showed the middle and low level environmental risk from the middle to the end of the experiment. The research results provide data support for the migration of As in wetlands, and have certain theoretical and practical significance for the ecological restoration of arsenic-contaminated lakes.

results matching ""

    No results matching ""