Environmental impact and associated health risk assessment of heavy metal accumulation in some common leafy vegetables grown in a hydroponic environment

Abstract

Hydroponic farming is a contemporary, sustainable technique for growing plants without soil, utilizing nutrient-dense aqueous solutions. This technique is gaining popularity for its capacity to conserve water, maximize space, and enhance agricultural yields. Nonetheless, despite its benefits, hydroponic farming is susceptible to contamination, especially from heavy metals. These pollutants can enter the system via water supplies, fertilizers, or growing media, presenting possible health hazards to consumers and environmental issues. Heavy metal contamination of food crops remains a significant public health concern, particularly with the increasing adoption of hydroponic cultivation systems. This study evaluated the accumulation, translocation, and human health risks associated with cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), and selenium (Se) in Talinum triangulare, Telfairia occidentalis, and Amaranthus spinosus cultivated under controlled hydroponic conditions. Metal concentrations in plant tissues were determined using standard analytical techniques, and bioaccumulation factor (BAF), bioconcentration factor (BCF), and translocation factor (TF) were calculated to assess uptake and mobility. Estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were employed to evaluate potential non-carcinogenic health risks. Results showed variable metal accumulation among species, with higher translocation observed for Cu. Although individual THQ values for all metals were below unity, the cumulative HI exceeded the recommended safety threshold, indicating potential health risks associated with long-term consumption. These findings highlight the need for careful monitoring of nutrient and metal composition in hydroponic systems to ensure food safety and protect public health.