An assessment of ecological and possible human health risks from Cr and Ni in sediments affected by the industrial marine area in Tuzla Aydinli Bay, Istanbul, Turkey between 2016–2020

Industrial activities are a significant source of metals released into the environment, and it is important to understand their impact. Therefore, this study aimed to assess the ecological and human health risks caused by Cr and Ni in sediments from the industrial marine area in Aydinli Bay, Istanbul, Turkey over five years (2016–2020) with its tributaries including the Marmara Sea and river connections. In this process, some physico- and geochemical properties of sediments, and ecological and human health risks caused by Cr and Ni in sediment were evaluated. Between 2016–2020, the mean concentrations of Cr and Ni changed 4.8 ± 1.6–67.6 ± 32.1 µg/g and 6.9 ± 2.0–8.5 ± 2.3 µg/g, 44.5 ± 69.5–211.1 ± 143.2 µg/g and 5.4 ± 3.4–20.5 ± 15.0 µg/g and 9.3 ± 4.8–81.7 ± 60.8 µg/g and 13.6 ± 2.8–19.3 ± 8.8 µg/g in the bay, the Marmara Sea, and river connections, respectively. The statistical results also indicated that the levels of Cr and Ni correlated with pH, organic matters, and inorganic carbon rather than calcium and magnesium. The geoaccumulation risk index of metals in all three sampling areas were categorized as no contamination, except for 2019 and 2020. Moreover, the contamination factors changed in a wide range from low contaminations to high contaminations. Non-carcinogenic and carcinogenic health risks from two exposure pathways (ingestion and dermal contact) were characterized and indicated no adverse heath effect on adults. On the other hand, the results of ecological and health risk assessments also showed that the Cr and Ni contamination was lower in Aydinli Bay compared to the Marmara Sea and the river connections. These results gave a strong indication that ecosystem-based protection, control and management are neccessary in this region.