Key Takeaways & Executive Findings
- •• • Industrial sources dominate heavy metal contamination in Hongjiannao Lake, contributing 35.44% of total load, with Hg, Cr, Zn, and Cu as primary factors; agricultural sources contribute 24.67%, natural 23.65%, and traffic 16.23%. • • Total heavy metal concentration dropped from 112.51 μg/L (2013–2016) to 58.80 μg/L (2017–2024), a 47.7% reduction, following the 2016 closure of small coal mines and ecological restoration, demonstrating policy effectiveness. • • Carcinogenic risk exceeded the alert threshold (1×10⁻⁴) at all sampling points for As (100% exceedance) and 16.67% for Cd, with adults facing 1.97–5.24 times higher risk than children, necessitating targeted remediation. • • Non-carcinogenic health risks (HI) were below 1 for all age groups, with the highest HI of 5.82×10⁻¹ for Pb in adult males, indicating negligible non-carcinogenic effects but underscoring Pb's relative contribution.
Abstract
To evaluate heavy metal contamination and human health risks in desert lakes, this study analyzed concentrations of seven heavy metals (Hg, Pb, Cu, Zn, Cd, Cr, As) in Hongjiannao Lake, Northern Shaanxi, from 2013 to 2024. The absolute principal component score-multiple linear regression (APCS-MLR) model quantitatively apportioned pollution sources, and a health risk assessment model evaluated non-carcinogenic and carcinogenic risks. Results showed average concentrations of the seven metals did not exceed background values, but 28.57% of sampling points exceeded background for As, with a maximum exceedance factor of 1.92. Total average concentration decreased from 112.51 μg/L (2013–2016) to 58.80 μg/L (2017–2024), attributed to the 2016 closure of small coal mines and ecological restoration around the 4A scenic area. Source apportionment identified four sources: industrial (35.44%), agricultural (24.67%), natural (23.65%), and traffic (16.23%), indicating industrial dominance. Non-carcinogenic risks were negligible, but carcinogenic risks exceeded the alert value (1×10⁻⁴), with adults at higher risk than children. Oral ingestion was the primary exposure pathway. As and Cd were key control elements, with exceedance rates of 100% and 16.67%, respectively. These findings provide a theoretical basis for health risk prevention and environmental management.
1. Introduction
Heavy metal contamination in desert lakes poses unique challenges due to limited water exchange and high evaporation, concentrating pollutants. Previous studies often relied on total metal concentrations, which fail to identify specific sources or quantify their contributions, hindering effective management. The APCS-MLR model offers a robust quantitative source apportionment, yet its application to desert lake systems remains sparse.
This study addresses the bottleneck by applying APCS-MLR to Hongjiannao Lake, a 4A scenic area impacted by coal mining and agriculture. By integrating 12 years of monitoring data (2013–2024) with health risk assessment, we provide a comprehensive source-receptor framework. The findings not only quantify source contributions but also link them to specific health risks, enabling targeted interventions for As and Cd, which are critical for protecting local residents and guiding environmental policy.
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ZHANG Yaning, PENG Yan, WU Xijun, DONG Ying, HE Xinlin, LIU Jing, LI Bingbing (2026). Source Apportionment and Health Risk Assessment of Heavy Metals in Hongjiannao Lake Based on the APCS-MLR Model. Journal of Environmental Engineering Technology. https://doi.org/10.13205/j.hjgc.202608025
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Frequently Asked Questions
What are the dominant pollution sources and their quantitative contributions to heavy metal contamination in Hongjiannao Lake?
APCS-MLR identified four sources: industrial (35.44%), agricultural (24.67%), natural (23.65%), and traffic (16.23%). Industrial sources, characterized by Hg, Cr, Zn, and Cu, are the primary contributors, followed by agricultural sources (As, Cu).
How did heavy metal concentrations change over the study period, and what factors drove the decline?
Total average concentration decreased from 112.51 μg/L (2013–2016) to 58.80 μg/L (2017–2024), a 47.7% reduction. This decline is attributed to the 2016 closure of small coal mines and ecological restoration projects around the lake, highlighting the effectiveness of policy interventions.
What are the specific health risks posed by heavy metals, and which elements require priority control?
Non-carcinogenic risks are negligible (HI < 1), but carcinogenic risks exceed the alert threshold (1×10⁻⁴) for As (100% of samples) and Cd (16.67%). Adults face higher risks than children, with oral ingestion as the primary exposure pathway. As and Cd are the key control elements.
How does the health risk vary across different age groups and genders?
Carcinogenic risk increases with age; adults have 1.97–5.24 times higher risk than children. For non-carcinogenic risks, adult males show the highest HI (e.g., Pb: 5.82×10⁻¹), but all remain below 1, indicating no significant non-carcinogenic threat.
What are the implications for environmental management and future monitoring?
The findings underscore the need for targeted control of industrial and agricultural sources, particularly As and Cd. Continuous monitoring is essential to track the effectiveness of remediation efforts and ensure the safety of drinking water for local residents.
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