Field assessment of progressive remediation of soil contaminated with lead-acid battery waste in response to compost application

Abstract

Addition of compost to heavy metal-contaminated soil has been employed to remediate contamination. Such rectification, however, depends on the type of compost and the contaminant involved. The efficacy of Mexican sunflower (MSC) and Cassava peel (CPC) composts applied at 0, 20 and 40 t/ha as well as inorganic fertilizer (NPK, 20:10:10) (100 kg N/ha) on the remediation of a battery waste-contaminated site in Ibadan, Nigeria was assessed. No compost or NPK fertilizer served as the control. The experimental design was a randomized complete block with 4 replicates. Soil analysis before and at 1, 2, 3 and 12 months after compost application was carried out. Mean lead (Pb) concentration (134,000 mg/kg) was high at this site. Twelve months after treatment, MSC and CPC applied at 40 t/ha had reduced the plant available lead concentration in the soil by 69 and 49%, respectively, whereas 20 t/ha had reduced the concentration by 58 and 34%, respectively. The relationships between soil lead and organic matter content (r = -0.75), phosphorous (r = -0.59) and pH (r = -0.77) were negative. NPK fertilizer had a limited effect (7% reduction) on Pb. Application of MSC at 40 t/ha brought about a remarkable reduction in Pb concentration.