Compost-mediated arsenic phytoremediation, health risk assessment and economic feasibility using Zea mays L. in contrasting textured soils

Abstract

Maize (Zea mays L.) is considered as a potential energy-yielding crop which may respond to compost application for arsenic (As) phytoremediation depending on soil type and compost application levels in soil. Here, we explored compost-mediated As phytoremediation potential of maize in the two different textured soils (sandy loam soil and clay loam soil) at varying As (0–120 mg kg⁻¹) and compost (0–2.5%) levels under glasshouse conditions. Results revealed that in the absence of compost maize plants grown at different soil As levels (0–120 mg kg⁻¹) accumulated 1.20–1.71 times more As from sandy loam soil than that of clay loam soil. The compost addition in soil at all levels, with 120 mg kg⁻¹As enhanced As accumulation in maize plants in the clay loam soil by 13%, while it reduced As phyto-uptake by 27% in sandy loam soil. This may be due to an increase in phosphate-extractable (bioavailable) soil As content from 2.7 to 3.8 mg kg⁻¹ in clay loam soil. The estimated daily intake (EDI) of As (0.03–0.15 μg g⁻¹ of body weight day⁻¹) was above the US EPA’s standard value. Arsenic phytoremediation potential of the maize plants was found to be economical for sandy loam soil with 1% compost level and for clay loam soil at 2.5% compost level, suggesting soil type specific dose dependence of compost for As phytoremediation programs.

Novelty statement: To our knowledge, the role of compost in economic feasibility of energy crops at contaminated soils in general, and in the growing of maize at As-contaminated soil in particular, has not been addressed, so far. Moreover, it is the first time to evaluate environmental and health risk of compost-mediated As phytoremediation in different soil types.

This study provided new insights of economic evaluation and risk assessment in the phytoremediation and mechanisms of compost in biomass production of energy crop at different As concentration. These aspects in phytoremediation studies are imperative to understand for developing safe, cost-effective and soil specific remediation strategies.

Keywords:

• Arsenic
• compost
• energy crop
• maize
• phytoremediation
• risk assessment

Acknowledgments

Dr. Tariq Mehmood acknowledges the Postdoctoral Research Fellowship awarded by the Chinese government at Hohai University, Nanjing, China. Drs Nabeel Khan Niazi and Irshad Bibi are thankful to the University of Agriculture Faisalabad.

Additional information

Funding

The authors are thankful to the Higher Education Commission (ProjectNos.6425/Punjab/NRPU/R&D/HEC/2016 and 6396/Punjab/NRPU/R &D/HEC/2016), Pakistan for providing financial support. Dr. Irshad Bibi acknowledges the support from the COMSTEQ-TWAS research grant 2018 [18-268 RG/EAS/AS_C].