Transport and transformation of colloidal and particulate mercury in contaminated watershed

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-03-02 DOI:10.1016/j.watres.2025.123428

Junyao Yan, Ruolan Li, Chuan Wang, Shaochen Yang, Mingyu Shao, Leiming Zhang, Ping Li, Xinbin Feng

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引用次数: 0

Abstract

Submicron colloids ubiquitously present in aquatic environments and can facilitate long transport of absorbed contaminants. Impact of particle size distribution on mercury (Hg) mobility and transformation in the complex aqueous matrices is still unclear. In this study, we considered Hg mine wastes as a natural Hg releasing source to local rivers, and collected water samples from the source to the downstream during high and low flow periods. The water samples were analyzed for Hg morphology, concentration, speciation, and isotope to understand transport and transformation dynamics along the river flows. We found that visible Hg compounds observed by transmission electron microscopy were mainly bound to particles with size fractions of <0.05 and >0.45 μm in the upstream, while the proportion of Hg bound to particles with 0.05-0.45 μm only accounted for 20.0 ± 17.1% of the total Hg (THg). With increasing distance from the mine waste pile in the downstream, nano-colloidal Hg (<0.05 μm) became the dominant from due to settling of large particles and remained constant throughout the whole river. The Hg isotope results also revealed that colloidal Hg could migrate steadily for long distances into the downstream. Most importantly, a significantly positive correlation was observed between the proportion of nano-colloidal Hg to water THg and the proportion of methylmercury (MeHg) to water THg, indicating nano-colloidal Hg as an important substrate for Hg methylation in the river. These results highlighted the pivotal role of the nano-colloidal particles as a significant reservoir for Hg in aquatic environment.

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.