Ecological and Health Risk Assessment in Sewage Irrigated Heavy Metal Contaminated Soils

Abstract

The huge loading of heavy metals in cultivated soils, ascribing to long term sewage irrigation, has led to serious soil pollution affecting crops as well as increasing risks to human health. Sewage irrigation is commonly followed in developing countries due to few obvious reasons: a shortage of good quality irrigation water and ample amount of soil nutrients contained in sewage water. However, long term sewage irrigation is causing a global threat not only to food security but also to nutritional quality. Although several reports on soil heavy metal pollution are being documented due to sewage water irrigation, a systematic compilation and in-depth study of the indices used to measure heavy metal related risk assessment is crucial. As heavy metal pollution negatively affects both the soil ecology as well as human health, ecological indices and human health risk assessment are being calculated, enticing the policymakers to understand the overall situation of heavy metal pollution. Such ecological indices include bioaccumulation index, individual contamination index, potential ecological risk, ecological risk factor etc. Human health indices include hazard index, hazard quotient, carcinogenic risk index etc. These indices highlight the heavy metal contamination levels in the sewage irrigated soils and its associated health risks. Therefore, keeping these views in mind, this chapter sought to succinctly compile, discuss several ecological monitoring and risk assessment indices related to heavy metal soil pollution and their interpretations through visualizations.