Measuring atmospheric pollution around junction 16 of the M25 Motorway, London, United Kingdom, using lichenophagous invertebrates

Abstract

AbstractWe investigate some environmental effects of exhaust emissions from motorway traffic in an area centered on the Junction 16 interchange of the M25 (London Orbital Motorway, UK) with the M40 (London‐to‐Birmingham Motorway, UK). This junction is surrounded by woodland and farmland, with urban development to the west and east. Both motorways carry large volumes of vehicular traffic, so one would expect exhaust‐related air pollution to be higher downwind of the junction than in the surrounding area. Epiphytic algae were collected, analyzed, and used as a pabulum for lichenophagous insect larvae. Analysis showed the concentrations of exhaust‐related heavy metals in algal samples collected downwind were generally higher than those for the surrounding areas. An experiment in which insect larvae were fed these algae identified 13 sites that were significantly affected in two discrete areas: the area with high metals to the east (downwind) of Junction 16, and an area of intensively managed forestry with low metals on the western edge of the survey area. These results suggest this methodology may be a useful screening tool for monitoring air quality and managing the biological effects of atmospheric contaminants. Data from such studies would increase the trophic representation of risk assessments for atmospheric contaminants.