Trophic transfer and biomagnification of four heavy metals in freshwater food web: a case study of Zhangze Lake

ABSTRACT

Heavy metals are a subject of widespread concern because of their persistence, potential toxicity, and accumulation in biological tissues. However, their biomagnification in food webs is still controversial and has not been studied in detail especially in freshwater ecosystems. This study investigated the trophic transfer and biomagnification of four heavy metals (Cu, Cd, Pb, and Hg) within the food web of the freshwater Lake Zhangze. The study showed that the trophic levels of aquatic consumers in the lake ranged from 2.00–4.53. The presence of Hg in sediments posed a strong ecological risk, and the integrated ecological risk was spatially reduced from the front of the dam to the tail of the reservoir. Planktivorous fish exhibited higher concentrations of Cu, Cd and Hg compared to other fish consumers. Heavy metals showed distinct bioaccumulation patterns within the food web, with Cu biomagnification primarily occurred at lower trophic levels, whereas Hg demonstrated biomagnification trends throughout the food web, while Cd and Pb rarely biomagnified within the food chain. Cu, Cd and Pb levels were effectively biodiluted with increasing biological trophic levels, whereas Hg levels increased with increasing trophic levels.

KEYWORDS:

• Heavy metals
• food web
• biomagnification
• trophic transfer
• Zhangze Lake

Acknowledgements

We are very grateful to Shanxi Zhangze Reservoir Management Co., Ltd. for allowing us to enter the field sites and for their assistance in the field work.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [grant no 51679191]; Shaanxi Provincial Natural Science Basic Research Program (Key Project): [grant no 2019JLM-60].

Notes on contributors

Ruijing Yang

Ruijing Yang is a PhD student in environmental engineering, focusing on water ecology management and restoration.

Minquan Feng

Minquan Feng is a professor in the State Key Laboratory of Eco-hydraulics in the Northwest Arid Region at the Xi'an University of Technology. He specializes in Water Environment Management and Ecological Restoration.

Zimeng Liu

Zimeng Liu is master's students majoring in environmental engineering, and they focus on eutrophication management based on food web.

Guoguo Liu

Guoguo Liu is master's students majoring in environmental engineering, and they focus on eutrophication management based on food web.