Yankuang ceshi (Sep 2019)
Distribution and Migration Characteristics of Selenium in the Soil-Plant System of Paddy Fields in the Pearl River Delta, Yamen Town
Abstract
BACKGROUND The distribution and migration of selenium in the natural environment is a hot topic. The results of a multi-purpose, regional, geochemical survey showed that the content of selenium in the Pearl River Delta Region soils was relatively high, which was suitable for the planting of selenium-rich agricultural products. However, the rule of selenium migration and transformation in the soil-plant system is not yet clear. OBJECTIVES To understand the distribution and migration of selenium in the soil-plant system. METHODS Taking Yamen Town, Jiangmen City, a typical selenium-rich area in the Pearl River Delta region as an example, selenium contents in rocks, weathered soils, paddy soils, shallow groundwater, irrigation water and rice samples were analyzed by atomic fluorescence spectrometry. RESULTS The mean selenium concentrations in the granite rocks, granite weathered soils, surface soils, profile soils, shallow groundwater, irrigation water and rice of Yamen Town were 0.0208mg/kg, 0.2325mg/kg, 0.5060mg/kg, 0.83mg/kg, 0.0003mg/L, 0.0004mg/L and 0.058mg/kg, respectively. The selenium contents in surface soils were equivalent to the soil background value of the Pearl River Delta (0.51mg/kg), the selenium contents of rice reached the standard of selenium-rich rice. CONCLUSIONS The rules of selenium migration in the soil-plant system are as follows:selenium migrates downward in the soil profiles, and migrates downstream along the direction of groundwater runoff. Soil selenium migrates to rice root easily, but migrates with difficulty from roots to the overground parts of rice. The study on the distribution and migration of selenium in the soil-plant system can provide a scientific basis for the exploitation and utilization of selenium-rich resources in this area.
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