Heavy Metal–Pesticide Co-Contamination Under Climate Change: A Systematic Review of Crop Uptake, Food-Chain Transfer, and Sustainable Mitigation

Heavy metal–pesticide co-contamination is increasingly relevant to food safety because interactions between contaminants can modify their mobility, persistence, bioavailability, and transfer from agricultural soils to edible crops. This systematic review synthesized evidence on the occurrence, environmental behavior, mechanistic interactions, crop uptake, food-chain transfer, and mitigation of metal–pesticide mixtures in agroecosystems under climate-related stress. The evidence synthesized in this review indicates that metal–pesticide co-contamination arises from overlapping agricultural, industrial, and atmospheric inputs. Across the included studies, metal–pesticide co-exposure was associated with synergistic, additive, or antagonistic responses, depending on contaminant identity, concentration, soil properties, and exposure conditions. Co-exposure was associated with altered contaminant mobility, uptake, and accumulation in edible tissues, with implications for dietary exposure and food-chain transfer. The reviewed evidence further indicates that variations in temperature, hydrological conditions, and soil redox dynamics influence contaminant persistence, mobility, transformation, and bioavailability, although these effects remain strongly context-dependent. Biochar, phytoremediation, plant–microbe consortia, and nano-enabled materials show potential to reduce contaminant mobility and crop uptake. Integrated, climate-adaptive monitoring and remediation strategies are needed to better protect soil health, food safety, and the human food chain, while accounting for substantial methodological heterogeneity across available studies.