The Use of Geological Background Reference Values for Soil Evaluation and Remediation: The Trajouce Ecopark Case-Study

Abstract

2015 was proclaimed as the ‘International Year of Soils’ (IYS) at the 68th UN General Assembly. While soil is recognized as an essential, finite and non-renewable natural resource, it is increasingly degraded or irreversibly lost due to poor management and urban and infrastructure expansion, both in the EU and at a global level.

Soil contamination in particular has not only negative impacts on human health and ecosystems but also on economy, by the reduction in environmental services as a result of loss of natural soil capital and costs of land rehabilitation. The number of contaminated sites in the EU may exceed half a million. However, only a few EU Member States have specific legislation on soil protection. While the European Commission decided in May 2014 to withdraw the proposal for a Soil Framework Directive, the 7th Environment Action Programme, which entered into force on 17 January 2014, recognizes that soil degradation is a serious challenge and provides that by 2020 land is managed sustainably, soil is adequately protected and the remediation of contaminated sites is in good progress in the EU.

In Portugal draft legislation on the prevention of contamination and remediation of soils that seeks to eliminate major gap in the national legislative framework and comply with international commitments, was submitted for public consultation and is now being discussed. Among several innovations, for the definition of reference values for evaluation and remediation of soil, natural background values can be used instead of those adopted from the Ontario Standards [MOE (Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act., April 15, 2011. Ministry of the Environment, 2011)], or other international standards, for the most common contaminants, if duly justified and accepted by the Environmental Portuguese Agency.

This paper reports a case study in which the conducted site investigation, sampling and interpretation of results confirmed the existence of a neat relationship between the presence of vanadium and geological background of the region where the Trajouce Ecopark (TRATOLIXO) operates, which allowed to classify the soil resulting from the treatment of several areas affected by the inadequate disposal of urban solid waste as suitable for environmental rehabilitation of the site [EGIAMB (Estudo das Concentrações Naturais de Vanádio na Envolvência do Ecoparque de Trajouce. Final Report, 2014)].