Arsenic (As) contamination in sediments from coastal areas of China.

Arsenic (As) from various anthropogenic sources has accumulated in estuarine and coastal sediments of China in the past decade, but we know little about the overall situation of As pollution at a national scale. Here, we analysed the spatial-temporal distribution characteristics, source, fate, and potential risks of As from 11 provincial-level regions across coastal China based on reviewed data extracted from previous studies published in the past 20 years. The anthropogenic contribution to As load was evident in 8 out of 11 provinces, especially in developed areas such as Tianjin, Zhejiang, and Guangdong. The weighted mean concentration of As in coastal sediments was 9.75 mg kg-1, which was close to national agricultural land (10.7 mg kg-1) and mixed land (12.1 mg kg-1) soil values, and this indicated the likely terrestrial influences and homogenization of As distribution at the interface between land and sea. The accumulation has decreased significantly since 2005, which might be due to continuously reduced emissions from farming and animal husbandry and household consumption in the catchment of coastal areas. The geoaccumulation index indicated that the proportions of unpolluted, unpolluted to moderately polluted, and moderately polluted cases were 48%, 28%, and 8%, respectively. This study provides a comprehensive and quantitative review on As contamination in coastal sediments on a national scale. The results could be used in coastal sediment quality assessment and decision-making by authorities to meet the regulatory requirements linked to coastal environmental protection and management.

Microplastics and environmental pollutants: Key interaction and toxicology in aquatic and soil environments.

Nowadays, a growing number of microplastics are released into the environment due to the extensive use and inappropriate management of plastic products. With the increasing body of evidence about the pollution and hazards of microplastics, microplastics have drawn major attention from governments and the scientific community. As a kind of emerging and persistent environmental pollutants, microplastics have recently been detected on a variety of substrates in the world. Therefore, this paper reviews the recent progress in identifying the sources of microplastics in soil, water, and atmosphere and describing the transport and fate of microplastics in the terrestrial, aquatic and atmospheric ecosystems for revealing the circulation of microplastics in the ecosystem. In addition, considering the persistence of microplastics, this study elucidates the interactions of microplastics with other pollutants in the environment (i.e., organic pollutants, heavy metals) with emphasis on toxicity and accumulation, providing a novel insight into the ecological risks of microplastics in the environment. The negative impacts of microplastics on organisms and environmental health are also reviewed to reveal the environmental hazards of microplastics. The knowledge gaps and key research priorities of microplastics are identified to better understand and mitigate the environmental risks of microplastics.