Phytoremediation of arsenic contaminated soil using cassava plants

Abstract

Arsenic (As) contamination in the environment is a significant global health concern. This study evaluates the potential of cassava (Manihot esculenta) as a remediation tool for As-contaminated soils. Five cassava cultivars were cultivated in soils with varying As concentrations, and morphological traits and As accumulation were assessed at four and six months after planting (MAP). The results indicate that high As concentrations (50 mg kg⁻¹) led to a 50% reduction in shoot dry weight, while moderate As levels (25 mg kg⁻¹) resulted in a 41% decrease. At 4 MAP, the R11 cultivar exhibited the highest As concentrations in roots (100 mg kg⁻¹) and stems (9 mg kg⁻¹), with a bioaccumulation coefficient of 2.2. Concentrations of As in storage roots (22 mg kg⁻¹) were lower than in adventitious roots (74 mg kg⁻¹). The number of nodal roots showed a positive correlation with As concentration in both stems (r = 0.74) and roots (r = 0.55) under high As conditions. Furthermore, high As contamination in cassava starch delayed ethanol fermentation by up to 12 h but did not significantly affect ethanol yields after 36 h. These findings suggest that cassava is a promising candidate for the remediation of As-contaminated soils.