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Dilution characteristics of riverine input contaminants in the Seto Inland Sea

Zhu, Junying, Guo, Xinyu, Shi, Jie, Gao, Huiwang
Marine pollution bulletin 2019 v.141 pp. 91-103
aquatic organisms, half life, heat transfer, hydrologic models, marine environment, prediction, risk, rivers, seasonal variation, summer, water pollution, wind speed, winter
Riverine input is an important source of contaminants in the marine environments. Based on a hydrodynamic model, the dilution characteristics of riverine contaminants in the Seto Inland Sea and their controlling factors were studied. Results showed that contaminant concentration was high in summer and low in winter. Contaminant concentration decreased with the reduction of its half-life period, and the relationship between them followed power functions. Sensitivity experiments suggested that the horizontal current and vertical stratification associated with air-sea heat flux controlled the seasonal cycle of contaminant concentration in the water column; however, surface wind velocity was the dominant factor affecting the surface contaminant concentration. In addition, contaminant concentration in a sub-region was likely controlled by the variations in river discharges close to the sub-region. These results are helpful for predicting contaminant concentrations in the sea and are expected to contribute to assessing the potential ecological risks to aquatic organisms.