Assessment of trace element contamination in soils around Chinnaeru River Basin, Nalgonda District, India

摘要

Concentrations of trace elements such as As, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Y, Zn and Zr were studied in soils to understand metal contamination due to agriculture and geogenic activities in Chinnaeru River Basin, Nalgonda District, India. This area is affected by the geogenic fluoride contamination. The contamination of the soils was assessed on the basis of geoaccumulation index, enrichment factor (EF), contamination factor and degree of contamination. Forty-four soil samples were collected from the agricultural field from the study area from top 10-50 cm layer of soil. Soil samples were analyzed for trace elements using X-ray fluorescence spectrometer. Data revealed that soils in the study area are significantly contaminated, showing high level of toxic elements than normal distribution. The ranges of concentration of Ba (370-1,710 mg/kg), Cr (8.7-543 mg/kg), Cu (7.7-96.6 mg/kg), Ni (5.4-168 mg/kg), Rb (29.6-223 mg/ kg), Sr (134-438 mg/kg), Zr (141.2-8,232 mg/kg) and Zn (29-478 mg/kg). The concentration of other elements was similar to the levels in the earth's crust or pointed to metal depletion in the soil (EF ＜ 1). The high EFs for some trace elements obtained in soil samples show that there is a considerable heavy metal pollution, which could be due to excessive use of fertilizers and pesticides used for agricultural or may be due to natural geogenic processes in the area. Comparative study has been made with other soil-polluted heavy metal areas and its mobility in soil and groundwater has been discussed. A contamination site poses significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects on terrestrial, groundwater and aquatic ecosystems.