The development of a risk-based approach to managing the ecological impact of pollutants in highway runoff

Abstract

In the UK, the Highways Agency is responsible for the strategic road network. It is recognised that current design guidance to control pollutants in highway runoff is out of date. A research programme is in progress to develop a better understanding of pollutants in highway runoff and their ecological impact. The paper summarises the outcome of a study to: (1) monitor pollutants in highway runoff under different climate and traffic conditions at 24 sites; (2) develop standards to assess potential ecological risks; and (3) develop a model to predict pollutant concentrations in highway runoff. Data collection and analysis of the resulting data have identified a link between pollutant concentrations and traffic density. A number of pollutants routinely present in highway runoff have been identified as posing the greatest ecological risk. Ecologically based standards for acute impacts have been derived for the soluble form of these pollutants. These standards will be used in conjunction with the model to indicate where runoff treatment may be required to mitigate ecological risk. The model and standards will be used to develop improved design guidance to protect receiving waters from pollutants in highway runoff by identifying where runoff treatment is required, and to what degree.

Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic tile and green roofs in Chongqing, China

“…It has been observed previously that there was a positive correlation between certain pollutant loads or concentrations and storm intensity measures (from highways) (Crabtree et al, 2008). In our study, the MRI showed a significant (P < 0.01) negative correlation with most parameters.…”

Critical review of heavy metal pollution of traffic area runoff: Occurrence, influencing factors, and partitioning

“…Traffic volume is mostly characterized by AADT and varies in this review between 100 and 328,000 vehicles per day. Although some authors have concluded that AADT has the greatest influence on runoff concentrations of metals (Mangani et al, 2005;Crabtree et al, 2008), it might not be the best indicator for traffic area runoff concentrations and should not be used as a sole predictor because it only explains approximately 30% of the variation in these concentrations Drapper et al, 2000;Kayhanian et al, 2003). Special cases of AADT are the traffic flow volume during sampling and between two sampling periods (Shinya et al, 2003;Hallberg et al, 2007;Li and Barret, 2008).…”

“…For potential toxic effects, the partitioning between the total and dissolved heavy metals is essential because the dissolved fractions are directly biologically available (Paulson and Amy, 1993;Crabtree et al, 2008). The toxicity of traffic area runoff has been investigated by various researchers Pitt et al, 1995;McQueen et al, 2010).…”

The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China

“…Kayhanian et al (2007) and Gan et al (2008) found that the event mean concentration (EMC) values of pollutants have a significant negative correlation with the rainfall volume. Some studies have found a positive correlation between the load or concentration of certain pollutants and rainfall intensity (Crabtree et al 2008), while others show negative relationships (Crabtree et al 2006;Kim et al 2005). Han et al (2006) found that the EMC of COD and total Kjeldahl nitrogen had a significant positive correlation with the antecedent dry period.…”