Half-Century Observations Reveal Slow and Pulsed Recovery from Heavy Mercury Pollution in a Major Temperate River

作者：Мaodian Liu, Qianru Zhang, Alexander V. Zhulidov, Tatiana Gurtovaya, Xingrui Cai, Wenzhe Guo, Л. С. Косменко, Nadezhda Pavlova, Hehao Qin, В. В. Шамов, A. I. Shiklomanov, I Volkov, Xuejun Wang, Changhao Xiao, Zhihao Zhang, С. В. Бердников, Peter A. Raymond · 发表于：Environmental Science & Technology · 年份：2025 · DOI：10.1021/acs.est.5c09152 · 被引用次数：2 · 研究领域：Mercury impact and mitigation studies、Coastal wetland ecosystem dynamics、Toxic Organic Pollutants Impact

Rivers deliver substantial mercury to coastal oceans, significantly impacting seafood safety. However, the time frame for mercury levels and fluxes in large rivers to return to a stable, low-pollution state following long-term industrial pollution remains unclear. The Amur River, the world's fifth longest and one of the largest temperate rivers, originates in Mongolia and flows along the China-Russia border. Heavy industrial wastewater discharges in the 1960s-1970s severely contaminated the river, while strict controls implemented in the late 1970s created a rare opportunity to evaluate how quickly a large river recovers from severe anthropogenic mercury pollution. Here, we present an unprecedented 43-year time series of monthly observations of particulate mercury export to determine the river's recovery time frame. We find that mercury concentrations at the river mouth tripled due to wastewater discharges. After a 90% cut in wastewater discharges, mercury levels remained at peak levels for four years, returning to near-background within approximately 15 years, representing the initial flushing of mobile mercury from the drainage network ("Baseline Recovery"). However, after the initial flushing, legacy mercury from historic wastewater discharges was remobilized by hydrologic events, triggering episodic pulses ("Disturbance Recovery") that peaked ∼20 years after controls and reached up to three times the levels of the 1960s-1970s industrial peak. This remobilization was drive...