Integrated assessment of land-to-river Cd fluxes and riverine Cd loads using SWAT-HM to guide management strategies

Lingfeng Zhou; Miaomiao Teng; Fanhao Song; Xiaoli Zhao; Fengchang Wu; Yaobin Meng; Yuanyi Huang; Karim C Abbaspour

doi:10.1016/j.jenvman.2023.117501

Integrated assessment of land-to-river Cd fluxes and riverine Cd loads using SWAT-HM to guide management strategies

J Environ Manage. 2023 May 15:334:117501. doi: 10.1016/j.jenvman.2023.117501. Epub 2023 Feb 17.

Authors

Lingfeng Zhou¹, Miaomiao Teng², Fanhao Song², Xiaoli Zhao², Fengchang Wu³, Yaobin Meng⁴, Yuanyi Huang⁵, Karim C Abbaspour⁶

Affiliations

¹ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: zhoulf@mail.bnu.edu.cn.
² State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: wufengchang@vip.skleg.cn.
⁴ School of National Safety and Emergency Management, Beijing Normal University, Beijing, 100875, China.
⁵ College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
⁶ 2w2e Consulting, GmbH, Mettlenweg 3, 8600 Duebendorf, Switzerland.

PMID: 36801696
DOI: 10.1016/j.jenvman.2023.117501

Abstract

In 2011, China invested US$9.8 billion to combat the severe heavy metal pollution in the Xiang River basin (XRB), aiming to reduce 50% of the 2008 industrial metal emissions by 2015. However, river pollution mitigation requires a holistic accounting of both point and diffuse sources, yet the detailed land-to-river metal fluxes in the XRB remain unclear. Here, by combining emissions inventories with the SWAT-HM model, we quantified the land-to-river cadmium (Cd) fluxes and riverine Cd loads across the XRB from 2000 to 2015. The model was validated against long-term historical observations of monthly streamflow and sediment load and Cd concentrations at 42, 11, and 10 gauges, respectively. The analysis of the simulation results showed that the soil erosion flux dominated the Cd exports (23.56-80.14 Mg yr^-1). The industrial point flux decreased by 85.5% from 20.84 Mg in 2000 to 3.02 Mg in 2015. Of all the Cd inputs, approximately 54.9% (37.40 Mg yr^-1) was finally drained into Dongting Lake; the remaining 45.1% (30.79 Mg yr^-1) was deposited within the XRB, increasing the Cd concentration in riverbed sediment. Furthermore, in XRB's 5-order river network, the Cd concentrations in small streams (1st order and 2nd order) showed larger variability due to their low dilution capacity and intense Cd inputs. Our findings highlight the need for multi-path transport modeling to guide future management strategies and better monitoring schemes to restore the small polluted streams.

Keywords: Heavy metal fluxes; Industrial point emission; Nonpoint source pollution; SWAT-HM model; Watershed management.

MeSH terms

Cadmium
China
Computer Simulation
Environmental Monitoring
Metals, Heavy* / analysis
Rivers
Water Pollutants, Chemical* / analysis

Substances

Cadmium
Metals, Heavy
Water Pollutants, Chemical