Transformation of Arsenic by Indigenous Soil Microbes as Affected by Phosphorus and Arsenic

Highly arsenic-polluted soil (16.5 mg kg^–1) of West Bengal, India, was used for isolation, screening and identification of indigenous soil microbes. Citrobacter koseri significantly removed (7.6) and bioaccumulated (4.95) highest arsenic in P₁₅As₁₅ treatment, while loss (2.9) was higher in P₁₀As₁₅. Similarly, Pseudomonas putida significantly removed (7.4) and bioaccumulate (4.8) highest as in P₁₅As₁₅ and while loss (2.8) was higher in P₁₀As₁₅. Percentage removal of As was 47–59, bioaccumulation was 29–38 and loss 17–23 with Citrobacter sp., while it was 47–58% (removal), 29–39% (bioaccumulation) and 17–21% (loss) with Pseudomonas putida. Maximum removal and bioaccumulation of phosphorus was 37.8% and 32.1% respectively, for P₁₀As₁₅ in Citrobacter sp. In P. putida it was 33.1% and 27.2% respectively, for P₁₀As₁₅. At the same level of arsenic, increase in phosphorus significantly increased its removal and bioaccumulation, but the opposite was true during calculation in terms of percentage removal and percentage bioaccumulation.