This study assessed heavy metal contamination and associated health risks in soils and crops in the vicinity of a mercury mine located in Tongren, Guizhou Province, China, focusing on mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), and chromium (Cr). The study used the Index of Geological Accumulation (Igeo) and Health Risk Assessment (HRA) to quantify the level of contamination and assess the potential risks. The results showed that Area I was the most severely contaminated, with 94.24% of the sample sites being heavily contaminated with mercury, followed by Area II and Area III with severe cadmium contamination. The health risk assessment showed that children were exposed to non-carcinogenic risks of mercury and cadmium that exceeded the safety thresholds, with mercury being the major non-carcinogenic factor, especially through oral intake. The study also assessed the contribution of each heavy metal to pollution, with mercury contributing the most to ecological and health risks, especially in Areas I and III. The study highlights the urgent need to strengthen pollution control strategies, focusing on mining activities and agricultural inputs, to reduce risks and protect public health.

Using acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N,N'-methylenebisacrylamide (MBA) along with leaf cellulose and weathered coal humic acid, a leaf cellulose-humic acid-based superabsorbent hydrogel was synthesized through a water-solution polymerization initiated by potassium persulfate. FTIR analysis confirmed the successful preparation of the composite hydrogel. SEM analysis showed the presence of numerous deep pores and pore structures on the surface of the composite superabsorbent hydrogel. TG analysis indicated that a good thermal stability of the composite hydrogel. The water absorption capacity, water retention ability, salt resistance, and water release performance of hydrogels were studied. Performance tests demonstrated that the water retention rate of superabsorbent hydrogel was 79.2% after 24 h at room temperature and 22.5% after 72 h. Sandy soil absorption release tests showed that the superabsorbent hydrogel could release water into sandy soil continuously, providing long-term water supply. In plant growth experiments, the incorporation of the superabsorbent hydrogel enhanced plant growth height, prolonged wilting time, and significantly promoted plant growth and development.