Understanding metal concentration and speciation in motorway runoff

Although highway runoff has historically been extensively studied, the increasing complexity of stormwater management means that there are still significant gaps regarding the reduction of soluble metals. The work reported in this paper addresses these challenges by analysing the presence and behaviour of iron, copper and zinc in runoff from junction 24 of the M1 motorway in the UK (peak traffic flow: 30,000 vehicles per hour) and comparing it with other urban sources of metals found in the same catchment (a local brook and sewage treatment works). The sampling site included an interceptor and a treatment lagoon and the event monitoring indicated a trend by which the metals did not change their concentration or particulate soluble proportion immediately, hence showing that pre- and post-storm conditions are important factors when analysing the solubility of metals and their behaviour. The data provided further evidence of the important influence of storm characteristics on metal concentrations in highway runoff, in particular the effects of an antecedent dry weather period (ADWP). In addition, this study also helped us to better understand how the release of sodium the application of de-icer for road maintenance in winter affects the availability of zinc.

Automated summary

This study examines the presence and behavior of iron, copper, and zinc in highway runoff and compares it with other urban sources of metals. The findings show that the concentration and solubility of metals do not immediately change, emphasizing the importance of pre- and post-storm conditions. Additionally, the study highlights the influence of storm characteristics on metal concentrations in highway runoff and the effects of de-icer application on zinc availability during winter road maintenance.