Biochar application mitigates heavy metal contamination and enhances growth and production of tomato under diverse wastewater irrigation scenarios

Abstract

Water scarcity is a pressing and emerging geopolitical and societal challenge that has intensified reliance on wastewater (WW) for irrigation, but its contamination with pathogens and noxious compounds such as heavy metals (HMs) poses serious risks to food safety and public health. This study highlights the need to evaluate the health risks associated with the potential consumption of tomatoe's irrigated with WW and the role of biochar (BC) in mitigating these risks. 2‐year trials were conducted to evaluate tomatoes grown in BC‐amended soil under WW irrigation at various locations of Faisalabad, Punjab, Pakistan. Data revealed that escalated use of WW caused adverse effects on plant growth (15% to 18.9%) and fruit quality parameters. Moreover, heavy metal concentration in plant tissues was markedly higher in the 2nd year of the trial, likely due to cumulative heavy metal enrichment in WW‐irrigated soils, and the trend of improvement was Uchkera site, followed by Satyana and UAF Farms. However, BC‐treated soil significantly enhanced chlorophyll contents, secondary metabolites production, osmoregulation, antioxidant activities and curtailed reactive oxygen species accumulation, thereby restoring plant growth, biomass production and fruit quality. The present study offers compelling evidence for the integration of BC‐soil amendment into WW‐based irrigation systems to promote sustainable food security and safety.