Road runoff contains a variety of contaminants that threaten aquatic systems. Pollutant mitigation is therefore an important function of sustainable drainage systems such as vegetated ponds. Vegetated ponds have a variety of treatment mechanisms that potentially can remove different pollutants. However, design is predominantly based on “black box” approaches. This study monitored a swale and vegetated pond receiving road runoff over two years to investigate the interaction of various pollutant removal processes. Storm runoff, pond water, and sediments were monitored for general water quality, metals, hexane extractable hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). A non‐exponential “first flush” was apparent for biochemical oxygen demand, chemical oxygen demand, and solids with higher concentrations seen during the early stages of storms; however, for hydrocarbons and PAHs peak concentrations were often seen later in storm events. Due to interference from natural compounds, PAHs are probably more appropriate than hexane extracts for tracking runoff pollutant fate. Pyrene, despite having low concentrations in water, accumulated in soils and sediments (median = 850 µg/g). Naphthalene was more mobile, but was effectively removed in the pond. Metals had similar concentrations to other studies, with large removals of particularly Cu and Zn. However, metals exhibited different deposition patterns, with Zn and Cu accumulating in pond inlet sediments and Ni and Cr accumulating at the outlet. The different behaviors and fates of pollutants means that refining design guidance is difficult and requires consideration of how specific mechanisms may be enhanced for prioritizing removal of pollutants that pose the greatest risk.
Sustainable drainage (SuDs) is an established method for managing runoff from developments, and source control is part of accepted design philosophy. However, there are limited studies into the contribution source control makes to pollutant removal, especially for roads. This study examines organic pollutants, total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), in paired source and non-source control full-scale SuDs systems. Sites were selected to cover local roads, trunk roads and housing developments, with a range of SuDs, including porous asphalt, swales, detention basins and ponds. Soil and water samples were taken bi-monthly over 12 months to assess pollutant loads. Results show first flush patterns in storm events for solids, but not for TPH. The patterns of removal for specific PAHs were also different, reflecting varying physico-chemical properties. The potential of trunk roads for pollution was illustrated by peak runoff for TPH of > 17,000 μg/l. Overall there was no significant difference between pollutant loads from source and non-source control systems, but the dynamic nature of runoff means that longer-term data are required. The outcomes of this project will increase understanding of organic pollutants behaviour in SuDs. This will provide design guidance about the most appropriate systems for treating these pollutants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.