Remediation of arsenic-contaminated soil by chelating agents in shallot plantation land in Bima, West Nusa Tenggara

Abstract

Arsenic (As) contaminated agricultural land in Bima is due to the use of synthetic fertilizers and excessive pesticides in the shallot cultivation system. One of the efforts to remediate the contaminated soil by using the chelating agent. The research aims to study the ability of various chelating agents to remediate As contaminated soil and also examined the effect of chelating agents on arsenic concentration in shallot bulbs and production. The study was conducted at the shallot production center of Kalampa Village, Woha Subdistrict, Bima Regency, West Nusa Tenggara, which indicated As contamination. The experiment used a randomized block design with three replication and five chelating agents i.e. biochar-compost, chitosan, EDTA, ammonium thiosulfate, zeolite, and control. All treatment of chelating agents can reduce As in the soil up to 70% and significantly different with control. Arsenic content in shallot bulbs with chelating agents treatment is within the safe limit (<1 mg kg-1). Biochar-compost significantly increased the shallot yield. Meanwhile, EDTA treatment did not support shallot production. Biochar-compost and zeolite are recommended for application due to their ability to remediate arsenic in the soil, the lowest concentration of arsenic in shallot bulbs, and the ability to support optimal shallot production.