Application of Baked Pig Manure Reduces Arsenic Concentrations in Plants Growing in Arsenic-Contaminated Soils

S. Kawai; S.M. Imamul Huq; S. Segawa; M. Islam; J.C. Joardar; M. Halder
Two experiments were conducted to determine the efficiency of application of baked pig manure (BPM) to reduce the arsenic (As) concentration in Japanese mustard spinach (JMS) (Brassica rapa var. perviridis) and Bangladesh spinach (BS) (Spinacia oleracea) that were grown in arsenic-contaminated Japanese andosol and Bangladesh alluvial soil, respectively. Soil As was artificially raised to 50 mg/kg. BPM was applied to soil at a concentration of 1%, 2%, and 3%; each treatment had four replications. The plants were grown in As-contaminated soil for 30 days. Soil and plant samples were analyzed for As and other elements. Plant As concentrations decreased significantly with BPM application compared to that in control plants in both experiments. The plant As concentrations based on plant dry weight (DW) were reduced by 61% and 49% in Japanese andosol and Bangladesh alluvial soil, respectively, compared with those of control plants. The total As uptake (μg/plant) was higher in JMS and lower in BS than that in controls. Plant DW increased significantly with increasing amounts of BPM, which might function to decrease the As concentration in plants. The phosphorous (P) contents of both JMS and BS increased significantly with BPM application, whereas the calcium content decreased. The decreased plant As concentration might be due to P supplied by BPM, which might competitively suppress As uptake. We conclude that BPM could be a cost-effective, environmentally friendly, non-toxic soil additive for reducing As concentrations in edible plants. This strategy will ultimately safeguard the food supply from As contamination.
Arsenic; Soil; Contamination; Baked Pig Manure (BPM); Vegetable; Phosphate
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