The bioaccumulation of heavy metals, such as Cr, Cd, Pb, and As, in vegetables irrigated with contaminated water represents a risk to human health. The objective of this study was to evaluate the Cr concentration in chayote fruits in sites irrigated with contaminated water from Lake Chapala and to assess the potential risk to human health using the estimated daily intake (EDI), objective risk quotient (THQ), and carcinogenic risk quotient (TCR). In parallel, interviews were conducted with local producers to understand their perceptions of the quality of irrigation water and their willingness to adopt more sustainable agricultural practices. In two of the sites and seasons, Cr concentrations exceeded the FAO-WHO limit of 2.3 mg·kg⁻¹ (from 2.49 to 4.82 mg·kg⁻¹). In all, 90% of producers used water from Lake Chapala to irrigate their crops, although most did not perform water quality analyses, despite 32% being aware that the water was contaminated. The results highlight the need to implement strategies to increase awareness of the quality of irrigation water, as well as the need for comprehensive public policies that combine technical assessments and producer perceptions to reduce the risks associated with the use of contaminated irrigation water to promote sustainable agricultural production.

Cadmium (Cd) is a contaminant that causes significant damage to organisms. In plants, it results in growth delay, alters photosynthetic function, and affects nutrient concentrations. This study aimed to evaluate the impact of Cd (0, 0,25, 0,50, and 1 µM) on chlorophyll content, structural damage to the root, and the absorption and translocation of nutrients (Ca, K, Mg, Mn, Fe, and Zn) in Phaseolus vulgaris var. Opus plants. An increase in chlorophyll a was observed at Cd concentrations of 0.25 and 1 µM. Chlorophyll b increased across all Cd treatments, while carotenoid content decreased in all treatments. The roots exhibited structural damage as Cd concentrations increased. For nutrients, Ca, Mg, Mn, and Zn in leaves, and K in stems, increased with higher Cd doses. Conversely, K in roots decreased with higher Cd concentrations, and Fe decreased compared to the control in all evaluated organs. Our results suggest that Cd stress at low concentrations stimulates chlorophyll synthesis and that varying Cd concentrations induce synergistic and antagonistic effects in different organs of P. vulgaris, leading to nutritional disorders. Given the global importance of this crop, studying the molecular mechanisms and membrane transporters in P. vulgaris roots exposed to Cd is crucial for enhancing its resistance to Cd.

Humic substances and beneficial microorganisms are key biostimulants for sustainable agriculture and global food security in the face of climate change. Marine bacteria are emerging as a promising source of plant-beneficial microbes, tapping into a microbial diversity as immense as the oceans themselves. However, their potential, limitations, and mechanisms of action––especially in combination with other biostimulants––remain largely unexplored. In this study, we isolated the Streptomyces sp. LAP3 strain from the giant limpet Scutellastra mexicana. We evaluated the efficacy of the marine bacterium, applied alone or in combination with the humic product Leonardite hydrolate (L), in enhancing tomato performance under field conditions. Treatments included: (1) marine Streptomyces (MS), (2) Leonardite hydrolate (L), (3) both biostimulants (MS + L), and (4) a control (CTRL). We assessed growth, photosynthetic performance, antioxidant responses, and fruit yield and quality. Both biostimulants individually improved plant performance, but their combination had a significant synergistic effect, markedly boosting tomato productivity, thermotolerance, and resilience during a heatwave. Enhanced photosynthetic efficiency and antioxidant enzyme activity were associated with improved agronomic traits. These results highlight the potential of combining Streptomyces sp. LAP3 and Leonardite hydrolate as an eco-friendly strategy to increase crop productivity, strengthen stress resilience, promote sustainable agriculture, and reduce reliance on agrochemicals.

Heavy metal contamination in agricultural production is a significant public health issue in Mexico, as it directly impacts food safety and population exposure through dietary intake. Available scientific evidence indicates that vegetables and other plant-derived foods can serve as significant exposure pathways for toxic elements such as arsenic, cadmium, lead, chromium, and mercury. The consumption of contaminated foods may contribute to cumulative adverse health effects, including neurological, renal, and reproductive alterations, as well as an increased risk of chronic diseases. In Mexico, risk assessment is further constrained by methodological heterogeneity across studies and by difficulties in translating scientific evidence into concrete regulatory actions. Critically, the national regulatory framework lacks specific standards establishing maximum permissible limits for heavy metals in fresh fruits, vegetables, and grains, despite their central role in the population’s diet. Regulations focus primarily on drinking water quality and selected processed foods, creating a regulatory gap in the direct control of contaminants in crops. The findings underscore the urgent need to strengthen public policies by establishing crop-specific regulatory standards, implementing systematic monitoring programs, and integrating food safety considerations more effectively into environmental, agricultural, and public health policies in Mexico.

Polluted water in the Chapala–Santiago basin (CSB) contains several genotoxic substances that present risks to human health, particularly among residents of communities surrounding Lake Chapala and the Santiago River, where a high prevalence of cancer has been documented. For this reason, it is necessary to study the genotoxic activity of these waters and the genetic damage in inhabitants of the surrounding populations. This study assessed the genotoxicity of water in various communities in the CSB and evaluated DNA damage to lymphocytes in residents of nearby locations. The alkaline comet assay was employed to evaluate water genotoxicity and DNA damage to lymphocytes in residents living near these waters. A standardized questionnaire was distributed to participants of this study to evaluate their exposure to polluted water. Significant genotoxic activity (p < 0.05) was observed in the lymphocytes of individuals exposed to contaminated water (tail length in Puente Grande 27.88 ± 5.4 compared to 3.77 ± 1.64 of negative control), along with notable DNA damage (p ≤ 0.05) to the lymphocytes of residents living in proximity to these waters (tail length in Juanacatlán 12.3 ± 3.4 compared to 1.4 ± 0.74 of negative control). The waters of the CSB possess the capacity to cause DNA damage; meanwhile, genotoxicity increases from Chapala to El Salto due to the additional input of genotoxic contaminants, thereby elevating the cancer risk for the exposed population. The comet test proved to be a useful tool that allowed data to be obtained quickly and reliably.