Geochemical baseline data for the urban area of Cardiff

This report presents the results of an urban soil geochemical survey of Cardiff carried out by the British Geological Survey (BGS) during 1994. The study was undertaken as part of the BGS systematic Geochemical Surveys of Urban Environments (GSUE) project. The concentrations of many potentially harmful elements (PHE) such as As, Cd, Cr, Ni and Pb are enhanced in city environments as a result of urbanisation and industrial processes and their distribution is of concern under current UK environmental legislation. The GSUE data provide an overview of the urban geochemical signature and because they are collected as part of a national baseline programme, can be readily compared with soils in the rural hinterland to assess the extent of urban contamination. The aim of the present study was to generate urban soil geochemistry information for Cardiff to aid planning and development. Urban surveying was based upon the collection of samples on a systematic 500 m grid. Soils were sampled at a density of 4 per km2 across the built-up area. Samples were collected from open ground as close as possible to the centre of each 500 m grid cell. Preliminary interpretations of the data in relation to the underlying geology and past and present industrial history of Cardiff are presented in this report and demonstrate that the majority of metal elements are elevated in the former industrial centre of the city around the docks reflecting anthropogenic influences. However, in general contaminant levels in Cardiff are similar to other city environments in the region