A recent report by Stormwater Shepherds and CIWEM (The Chartered Institution of Water and Environmental Management) has shed light on the issue of toxic runoff in the UK. The report focuses on the dangerous pollutants that enter water sources when it rains, including tyre particles, fuel spills, and heavy metals; all of which come from the UK’s road network. Highway runoff pollution has been largely overlooked despite evidence that toxic runoff containing harmful pollutants like microplastics, metals, hydrocarbons enter rivers and affect aquatic life.
The report highlights the carcinogenic and hormone-disrupting effects of pollutants on aquatic life. It also points out the lack of monitoring and control of highway outfalls, despite being a statutory duty and the voluntary agreement that exempts them from permits. This has led to exceeding environmental quality standards (EQS). The report reinforces that various treatment options exist, including sediment removal and vegetative treatment devices, but they require proper design, implementation, and maintenance. The report suggests further research, improved monitoring, a catchment approach to management, and better regulatory control to mitigate pollution from highway runoff.
The report makes several recommendations to the government focussed on managing the environmental impact of roads. These include controlling pollutants at source, improving drainage and treatment, revising the Highways England Water Risk Assessment tool (HEWRAT) through collaboration with the environment agency, adoption of catchment-based approaches to water pollution risk and mitigation, a budget settlement agreement, consideration of pollutant levies to fund remediation or stormwater utilities levy and introducing permits for high-risk outfall zones.