The future of urban soil policy in Cork, Ireland

Abstract

Urban soils are prone to accumulating metals over time. This is caused by the proximity of urban soils to roads and industry, among other sources. In Europe, many urban areas show metal enrichment linked to anthropogenic activity. The public are in contact with urban soils on a regular basis. This potentially has adverse effects on human health, especially in locations with enrichment of metals that are systemic toxicants, such as As, Cd, Cr, Hg and Pb. Despite this, most European countries lack dedicated policy on urban soils. In Ireland, data on urban soil metals exist for only two urban centres (Dublin and Galway), both of which show anthropogenic enrichment of metals. Cork city is an ideal target for study of urban soil metals because its history includes over 200 years of industrial development, and its urban parks include former brownfield and industrial sites. Here, we measured concentrations of urban soil metals for ten sites in Cork city using a portable XRF (X-ray fluorescence) analyser. In addition, two sites were selected for ICP-MS analysis in order to provide an independent test of the accuracy of the XRF data.  Our results show that at all ten Cork sites, Pb is highly enriched in soils, with concentrations up to ten times greater than natural background levels. Fe, Mn and Zn are moderately enriched at each of the ten sites, with concentrations typically between two to five times natural background levels. Metal concentrations are systematically higher at sites in the city centre than suburban sites. These patterns of metal enrichment are similar to those seen in urban soils elsewhere in Europe. Future EU policy is essential for the assessment of urban soils and for the remediation of contaminated sites. This research has already helped to inform the Geological Survey of Ireland and the Government of Ireland Department of the Environment, Climate and Communications to help facilitate the implementation of data-driven legislation. It is anticipated that a relevant soil policy will come into effect in the coming years, which will aid the assessment and remediation of contaminated urban soils across Ireland.