Novel Approaches for the Investigation and Remediation of the Environmental Impacts of Mercury in the Environment

Abstract

The focus of this project was to develop and apply novel approaches to investigate Hg chemical speciation in the environment and explore methods that could be used for its remediation. Findings are presented as three research papers. Better understanding the mobility and chemical speciation of solid phase Hg at a site is critical for thorough risk assessment. In Paper 1, advanced analytical techniques [e.g. X-ray Absorption Spectroscopy (XAS)] were applied to identify the chemical speciation of Hg in a canal bed (MLR) sediment impacted by legacy discharge from industry. A sequential extraction protocol (SEP), in combination with ICP-MS, was applied to establish the potential mobility and potential bioavailability of highly toxic Hg. X-ray Diffraction (XRD) indicated that the sediment mineralogy was dominated by calcite and brucite, which are key components of solid waste from Hg-cell chlor-alkali plants. SEPs revealed that the bulk of Hg (>97%) was recalcitrant, likely strongly complexed, or mineral bound, and therefore relatively immobile with limited bioavailability. XAS revealed that >85% Hg was beta-HgS, and the bulk of the remaining portion was likely Hg(II) sorbed to sediment. Organometallic methylmercury (MeHg) [55 ± 1 μg/kg] potentially poses the largest risk, despite contributing

Date of Award	1 Aug 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Polya (Supervisor), Samuel Shaw (Supervisor) & Jonathan Lloyd (Supervisor)