Potentiality of iron slime as an amendment for arsenic-contaminated soil

Iron slime, the by-product of steel industry, is of environmental and ecological concern due to its disposal problem. An incubation experiment was conducted with the iron slime to study its effect on soil properties with special reference to arsenic retention in arsenic-contaminated soil. The experiment was conducted in factorial completely randomized design with three levels of arsenic spiking: 0, 5 and 10 mg kg −1 and three doses of iron slime: 0, 10 and 20 g kg −1 in three different arsenic status soils under submergence for 90 days. Application of iron slime significantly increased organic carbon and available phosphorus content in soil with increase in the dose of iron slime irrespective of level of arsenic spiking and initial soil arsenic status. Available phosphorus content in soil is increased by 10.89, 7.58 and 23.85% with 20 g iron slime kg −1 soil in low, medium and high arsenic soil over their respective control. On the other hand, available arsenic content in soil decreased with increasing dose of iron slime. Available arsenic concentration in soil is declined by 34.6, 45.9 and 46.7% from their respective initial arsenic status in low, medium and high arsenic status soil with the application of 20 g iron slime kg −1 soil. Considering the positive effect of iron slime on increasing organic carbon, available phosphorus content in soil, and retaining arsenic in plant unavailable form, it can be considered as an efficient amendment for arsenic-contaminated soils.