Evidence on the exposure Index’s substitution effect in assessing brook pollution risk in urban–rural fringe

Abstract

Brooks are significant ecological sources and migration channels of material flow as well as energy flow in urban–rural fringes. Despite their significance, the absence of monitoring data poses challenges in assessing brook pollution risk. Taking Muli Brook as an example, a spatiotemporal variability of water quality was revealed through sample collection and water chemistry analysis. We reveal spatiotemporal variability of pollution and then developed an Exposure Index (EPI), verifying its substitution effect in assessing brook pollution risk. Our findings demonstrate a downward trend in pollution from 2020 to 2022, with exceptions in dissolved oxygen (DO) and pH. Notably, more severe pollution is observed during spring and summer, influenced by seasonal production activities and extreme weather events. Despite the diminishing disparity near urban areas, the cumulative influence of upstream pollutants outweighs that of surrounding human activities. Stronger associations between pollution risks and water area EPI were observed, compared to those of construction land and farm land. In conclusion, EPI emerges as a valuable tool for assessing brook pollution risks in urban–rural fringes, offering precise insights into brook habitat characteristics, especially in the absence of consistent monitoring data.

Keywords

• Exposure Index
• Pollution risk
• Urban-rural fringe
• Brook