Significant impacts of river inputs on the distributions and transports of mercury and methylmercury in nearshore and open seas - Simulation based on field surveys and mass balance modeling

Chenghao Yu; Huiming Lin; Junming Guo; Mao Peng; Maodian Liu; Yindong Tong; Yifan Lu; Xuejun Wang; Xiangliang Pan

doi:10.1016/j.envint.2023.108216

Significant impacts of river inputs on the distributions and transports of mercury and methylmercury in nearshore and open seas - Simulation based on field surveys and mass balance modeling

Environ Int. 2023 Oct:180:108216. doi: 10.1016/j.envint.2023.108216. Epub 2023 Sep 19.

Authors

Chenghao Yu¹, Huiming Lin², Junming Guo³, Mao Peng⁴, Maodian Liu², Yindong Tong⁵, Yifan Lu⁶, Xuejun Wang⁷, Xiangliang Pan⁸

Affiliations

¹ Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
² Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
³ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China.
⁴ Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
⁵ School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; College of Ecology and Environment, Tibet University, Lhasa 850000, China.
⁶ Zhejiang Construction Investment Environment Engineering Co., Ltd., Hangzhou 310014, China.
⁷ Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address: xjwang@urban.pku.edu.cn.
⁸ Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China. Electronic address: panxl@zjut.edu.cn.

PMID: 37738696
DOI: 10.1016/j.envint.2023.108216

Abstract

Rivers are important sources of Hg for adjacent seas, and seafood from nearshore waters is a major source of Hg exposure for humans. There is thus a key scientific concern regarding how much riverine Hg inputs influence Hg loads in nearshore waters as well as how far the impact range can extend from the river to the open sea. In addition, it is important to understand the influence of anthropogenic hydro-facilities and activities on Hg levels in downstream seas. Because of the concise mass exchange pattern between the seas and the previously demonstrated intensive Hg inputs under anthropogenic regulation from the Yellow River, the Bohai and Yellow Seas, which are key fishery and marine breeding areas for China, are an ideal research area for exploring the impacts of riverine Hg on nearshore and adjacent open seas. Field surveys were conducted in eight major rivers and two seas, and 433 water samples were collected. The main Hg input and output terms (rivers, ocean currents, underground discharge, sewage, coastal erosion, atmospheric deposition, surface evasion, sedimentation, and fisheries) were quantified in the Bohai and Yellow Seas. Owing to the high inputs from the Yellow and Yalu Rivers, elevated THg concentrations were found. Apart from direct MeHg discharge, riverine nutrients may also seemingly affect nearshore MeHg. Using mass balance models, we found that the Yellow River (9.8 t) was the dominant Hg source in the Bohai Sea, which accounted for more than half of all contributions, and the Bohai Sea played the role of a secondary source of Hg to the Yellow Sea, with a flux of 3.3 t. Anthropogenic hydro-activities in large rivers could significantly influence Hg outputs and loads in the nearshore and even open seas. This study provides useful information for water resource management applications to reduce potential MeHg risks.

Keywords: Mercury; Methylmercury; Nearshore Sea; Open Sea; River.