Mitigation of methylmercury production in eutrophic waters by interfacial oxygen nanobubbles

Pan, G ORCID: https://orcid.org/0000-0003-0920-3018, Ji, X, Zhang, M, Liu, C and Yin, Y, 2020. Mitigation of methylmercury production in eutrophic waters by interfacial oxygen nanobubbles. Water Research, 173: 115563. ISSN 0043-1354

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Abstract

In mercury (Hg)-polluted eutrophic waters, algal blooms are likely to aggravate methylmercury (MeHg) production by causing intensified hypoxia and enriching organic matter at the sediment-water interface. The technology of interfacial oxygen (O2) nanobubbles is proven to alleviate hypoxia and may have potential to mitigate the risks of MeHg formation. In this study, incubation column experiments were performed using sediment and overlying water samples collected from the Baihua Reservoir (China), which is currently suffering from co-contamination of Hg and eutrophication. The results indicated that after the application of O2 nanobubbles, the %MeHg (ratio of MeHg to total Hg) in the overlying water and surface sediment decreased by up to 76% and 56% respectively. In addition, the MeHg concentrations decreased from 0.54 ± 0.15 to 0.17 ± 0.01 ng L−1 in the overlying water and from 56.61 ± 9.23 to 25.48 ± 4.08 ng g−1 in the surface sediment. The decline could be attributed to the alleviation of anoxia and the decrease of labile organic matter and bioavailable Hg. In addition, hgcA gene abundances in the overlying water and surface sediment decreased by up to 69% and 44% after the addition of O2 nanobubbles, as is consistent with MeHg occurrence in such areas. Accordingly, this work proposed a promising strategy of using interfacial oxygen nanobubbles to alleviate the potentially enhanced MeHg production during algal bloom outbreaks in Hg-polluted eutrophic waters.

Item Type:	Journal article
Publication Title:	Water Research
Creators:	Pan, G., Ji, X., Zhang, M., Liu, C. and Yin, Y.
Publisher:	Elsevier
Date:	15 April 2020
Volume:	173
ISSN:	0043-1354
Identifiers:	Number Type 10.1016/j.watres.2020.115563 DOI S0043135420300993 Publisher Item Identifier 1281788 Other
Divisions:	Schools > School of Animal, Rural and Environmental Sciences
Record created by:	Jonathan Gallacher
Date Added:	31 Jan 2020 16:59
Last Modified:	04 May 2020 13:43
URI:	https://irep.ntu.ac.uk/id/eprint/39147

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