Terrestrial mercury and methylmercury bioaccumulation and trophic transfer in subtropical urban forest food webs

Fudong Zhang; Zhidong Xu; Xiaohang Xu; Longchao Liang; Zhuo Chen; Xian Dong; Kang Luo; Faustino Dinis; Guangle Qiu

doi:10.1016/j.chemosphere.2022.134424

Terrestrial mercury and methylmercury bioaccumulation and trophic transfer in subtropical urban forest food webs

Chemosphere. 2022 Jul:299:134424. doi: 10.1016/j.chemosphere.2022.134424. Epub 2022 Mar 26.

Authors

Fudong Zhang¹, Zhidong Xu², Xiaohang Xu³, Longchao Liang⁴, Zhuo Chen⁵, Xian Dong⁴, Kang Luo⁶, Faustino Dinis⁷, Guangle Qiu⁸

Affiliations

¹ School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
² State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
³ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China.
⁴ School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China.
⁵ School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China. Electronic address: chenzhuo19@163.com.
⁶ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, 676200, China.
⁷ College of Agriculture, Guizhou University, Guiyang, 550025, China.
⁸ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China. Electronic address: qiuguangle@vip.skleg.cn.

PMID: 35351481
DOI: 10.1016/j.chemosphere.2022.134424

Abstract

As the "lungs of the city", urban forests can improve air quality by absorbing air pollutants, becoming hotspots for mercury (Hg) pollution from anthropogenic activities. However, the bioaccumulation and transfer of Hg in the urban forest food web are unclear. In this study, total mercury (THg) and methylmercury (MeHg) concentrations, as well as the stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) in organisms with different trophic levels (TLs) were investigated in a mid-subtropical urban forest of the Changpoling Forest Park (CFP) in Guiyang City, Guizhou Province, southwestern China. The results showed that THg and MeHg among all taxa ranged from 5.6 to 1267 ng g^-1 and 0.046-692 ng g^-1, respectively. MeHg% (% of Hg present as MeHg) at different TLs exhibited a wide range of 5.0-69% on average. Both THg and MeHg increased with the TLs from plants to nestling birds, indicating distinct biomagnification through the food web of grasses/pine needles - grasshoppers/caterpillars/katydids/mantis - spiders/songbird nestlings. The trophic magnification slope (TMS) of THg and MeHg were 0.18 ± 0.05 and 0.37 ± 0.08, respectively, suggesting both of them significantly increase along food webs. These findings improve the understanding of biogeochemical Hg cycles in terrestrial food webs and highlight the impacts of terrestrial MeHg on nestling birds.

Keywords: Biomagnification; Stable isotopes; Terrestrial mercury and methylmercury; Urban forest's food webs.

MeSH terms

Animals
Bioaccumulation
China
Environmental Monitoring
Fishes
Food Chain
Forests
Mercury* / analysis
Methylmercury Compounds*
Water Pollutants, Chemical* / analysis

Substances

Methylmercury Compounds
Water Pollutants, Chemical
Mercury