XiaoBinbin,GuoWenlu,WangXiaofeng,et al.Distribution and Risk Assessment of Heavy Metals in Water Supply and Drainage Cycle of a Southern City[J].China Water & Wastewater,2026,42(13):69-75.
Distribution and Risk Assessment of Heavy Metals in Water Supply and Drainage Cycle of a Southern City
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第13期
Page:
69-75
Column:
Date of publication:
2026-07-01
- Keywords:
- water supply and drainage cycle; heavy metal; As; Hg; risk assessment
- Abstract:
- To further understand the distribution and associated risks of heavy metals in the water supply and drainage cycle of a city in southern China, monitoring data on water quality and sludge from the water supply and drainage system between 2020 and 2022 were used as evaluation indicators. A comprehensive assessment was conducted on raw water (surface water), drinking water, wastewater, and sludge using the single factor pollution index, water quality index (WQI), species sensitivity distribution (SSD) risk assessment method, water environmental health risk assessment model, and sludge potential ecological risk assessment method. The results showed that, except for arsenic (As) and mercury (Hg), the concentrations of other heavy metals in raw water (surface water) were extremely low. As concentration was low but exhibited significant seasonal variation, while Hg concentration remained low but increased notably in 2022. The annual average WQI values ranged from 0.33 to 2.68, indicating that the overall heavy metal pollution level ranged from non-pollution to mild pollution. The risk quotients for As and Hg didn’t exceed 0.29 and 0.74, indicating a moderate ecological risk level. The health risk assessment of the water environment showed that the overall health risk of drinking water reached 10-5, classified as a moderate risk level, with As being the main carcinogenic factor. Although the concentration of heavy metals in the influent of the wastewater treatment plant varied and was not high, the effluent quality met the discharge standards. However, the high total mercury values approached the discharge limit (1 μg/L).The comprehensive ecological risk index for sludge from water supply and drainage operations was below 150, indicating a low potential ecological risk. Nevertheless, the potential ecological risk coefficient for cadmium (Cd) was 64, which was significantly higher than that of other heavy metals, making Cd the primary pollutant in the sludge from water supply and drainage systems. Through a qualitative and quantitative combination of multiple methods, it was concluded that the main risk sources in the water environment of the study area were As and Hg, while the main risk source in the sludge was Cd.
Last Update:
2026-07-01