Assessing the impact of historical coastal landfill sites on sensitive ecosystems: A case study from Dorset, Southern England

Uncontrolled landfill disposal can cause the release of significant contamination. In Southern England and in other parts of the UK, historical landfills are located along many coastal and estuarine marshes and mudflats. At these sites waste, often significantly contaminated with heavy metals and other contaminants, was dumped with little engineering control and without regard to the surrounding environment. The aim of this study is to investigate the degree to which heavy metals from these historical sites may have contaminated adjacent marshes and mudflats, using the Lodmoor marsh, Dorset, UK as a test site.Surface and sediment core samples were collected from brackish marsh and mudflat areas around the former landfill at Lodmoor, which was operational between 1949 and 1990. Sediment samples were investigated for metallic pollutants, grain size, and mineralogy, and core samples dated via 137Cs and 210Pb. To examine the transfer of heavy metals through the food chain, Phragmites australis leaves were analysed for metallic pollutants. Geochemical data revealed that sediments from the Lodmoor marsh are probably contaminated with Pb. 137Cs dating indicates that concentration maxima for heavy metals correlate to the 1950s and 1960s when landfill activities commenced in Lodmoor. Shallow electromagnetic surveys indicate potential continued leaching from the historic landfill complex.This study indicates the potential for possible landfill-derived contaminants to persist in coastal systems for decades after landfill closure. Over the longer term, it is possible that salinisation and enhanced coastal erosion may cause significant metal release from the landfills and their surrounding sedimentary systems into adjacent ecosystems.

► Geochemical data revealed likely Pb contamination.
► 137Cs dating indicated period of maximum contamination dates to the 1950s and 1960s.
►  Contaminants from landfills may persist in coastal systems after landfill closure.
► Electromagnetic surveys indicated potential for continued leaching of contaminants.