Source-oriented ecological risk assessment of heavy metals in sediments of West Taihu Lake, China

Contamination and health risk assessment of heavy metals in soil surrounding an electroplating factory in JiaXing, China

A total of 30 samples from the downwind direction of a certain electroplating company in Jiaxing were collected in layers to analyze their heavy metal content. The soil risk assessment was conducted from the perspective of ecological and human health risks using the ground accumulation index method and human health risk assessment method. The results showed that in all samples, cadmium and arsenic far exceeded the soil background values, with an average exceeding multiple of 14.31 and 64.42, respectively, and a exceeding rate of 100%. After evaluation by the ground accumulation index, among these six heavy metals, arsenic and cadmium belong to extremely serious pollution levels. The human health risk assessment of electroplating plants found that in the exposure risk assessment, the ingestion value was much greater than the harm caused by breathing and skin, and the maximum exposure damage value of arsenic to children and adults was 4.17 × 10-3, among the carcinogenic risks, the risk brought by consumption is much greater than the respiratory and skin carcinogenic risk index, with the highest value score of 3.37 for cadmium, arsenic, and zinc carcinogenic risks 3.37 × 10-6, 2.42 × 10-3, 1.10 × 10-4.

Strong bacterial stochasticity and fast fungal turnover in Taihu Lake sediments, China

Understanding the assembly and turnover of microbial communities is crucial for gaining insights into the diversity and functioning of lake ecosystems, a fundamental and central issue in microbial ecology. The ecosystem of Taihu Lake has been significantly jeopardized due to urbanization and industrialization. In this study, we examined the diversity, assembly, and turnover of bacterial and fungal communities in Taihu Lake sediment. The results revealed strong bacterial stochasticity and fast fungal turnover in the sediment. Significant heterogeneity was observed among all sediment samples in terms of environmental factors, especially ORP, TOC, and TN, as well as microbial community composition and alpha diversity. For instance, the fungal richness index exhibited an approximate 3-fold variation. Among the environmental factors, TOC, TN, and pH had a more pronounced influence on the bacterial community composition compared to the fungal community composition. Interestingly, species replacement played a dominant role in microbial beta diversity, with fungi exhibiting a stronger pattern. In contrast, stochastic processes governed the community assembly of both bacteria and fungi, but were more pronounced for bacteria (R2 = 0.7 vs. 0.5). These findings deepen the understanding of microbial assembly and turnover in sediments under environmental stress and provide essential insights for maintaining the multifunctionality of lake ecosystems.