Industrial impacts on vanadium contamination in sediments of Chinese rivers and bays.

Vanadium, like many trace metals, is persistent and detrimental to ecosystems at elevated concentrations. Likewise, it is versatile, functional, and used in many industries. Jiaozhou Bay (JZB) and Laizhou Bay (LZB) are valuable coastal ecosystems in China coexisting with several of these vanadium-related industries; however, limited studies have been conducted regarding vanadium occurrence, distribution, sources and risks in sediments. 208 surface sediment samples were collected from rivers and bays over two years and analyzed using inductively coupled plasma optical emission spectrometry. Overall, sediments near vanadium-related industries have significantly higher vanadium concentrations than those near traditional industries, with 30.3% and 22.9% higher average concentrations of vanadium in sediments of JZB and LZB, respectively. Vanadium accumulation at LZB is positively correlated with fine sediment, oxides (e.g., Fe, Ti, Mn), and organic matter content, while temporal changes in parts of JZB highlight the impacts of oxides, pH, and redox conditions on its accumulation. After geochemical normalization, the concentrations in marine samples from LZB showed slightly polluted sediments under the Modified Nemerow pollution index. Likewise, the elevated concentrations of vanadium in JZB, rivers and bay, were classified as slightly polluted and correlated with anthropogenic activities, such as the coal and petrochemical industries. Temporal changes indicated higher enrichments in 2019. Last, humans could be responsible for up to 46.8% and 16.2% of the vanadium accumulation in JZB and LZB, respectively, yet risks to species remain limited.