Assessing the ecological and health implications of soil heavy metals in vegetable irrigated with wastewater in calcareous environments

Abstract

The introduction of heavy metals from wastewater irrigation to the soil-crop-human biological domain has become a vital environmental and human health challenge. We evaluated the impact of wastewater irrigation (WW) on the severity of heavy metal pollution and health risk potential in different vegetables under WW versus fresh water (FW) irrigation. A multifaceted assessment was conducted using the pollution index (PI), ecological risk (ER), bio-concentration factor (BCF), hazard quotient (HQ), overall hazard index (HI), carcinogenic risk (CR), the bio-concentration factor (BCF), and total carcinogenic risk (TCR). The findings revealed that WW irrigation increased metal concentrations across all soil samples and vegetables in the order of Cd > Zn > Pb > Cu and Zn > Cu > Pb > Cd, respectively., The PI and ER indices indicated a significant increase of 27–330% and 260–310%, respectively in the WW-irrigated soils compared to the FW-irrigated soils. The heavy metals concentrations in the edible tissues of vegetables and their associated BCF values under WW irrigation exhibited the orders, Zn > Cu > Pb > Cd and Zn > Cu > Cd > Pb >, respectively Cabbage had the greatest potential to take up heavy metals compared with other crops. The mean HQ and HI were in the low risk category (0.1 ≤ HQ and HI < 1). Likewise, CR and TCR values were within acceptable limits (1.00E-06–1.00E-04) by consuming veggies produced with WW to children and adults, implying that there are no significant health risks to local inhabitants. However, the levels of HQ, HI, CR, and TCR were significantly higher in vegetables grown with WW than in those irrigated with FW, suggesting that wastewater irrigation may have a detrimental impact on human health.