From Page 32, June/July 1998
Site Restoration in Europe
Risk-based environmental management
By Martin Whittaker, James Sprenger & Matt Mculloch
Risk assessment is a key aspect of the Austrian Federal Environment Agencyís regulatory framework for environmental protection and restoration. A risk assessment methodology has been developed by the FEA based on the use of site-specific data and on the "top down" principle. Application of risk assessment is on two levels: by local authorities, on a case-by-case basis, and by the FEA, who act federally where systematic, nationwide guidelines are pertinent.
Use of risk assessment in Belgium is rooted principally in regulations relating to soil remediation. For historic contaminated sites, remediation must be undertaken if there is a potential for serious threat to human and/or ecological health, whereas for more recent or on-going contamination, remediation must be undertaken if soil quality criteria are exceeded. The soil cleanup standards themselves have been developed by the Flemish Institute for Technological Research using the Human Exposure to Soil Pollution (HESP) exposure model, that takes into account five different land uses (nature, agricultural, residential, recreational and industrial) and bases maximal exposures on Tolerable Daily Intake values for non-carcinogens and incremental lifetime cancer risks of one person in 100,000 for carcinogens.
In Denmark, the application of risk assessment is enshrined within the Contaminated Sites Act (revised 1996) and the Environmental Protection Act (amended 1996). Within this framework, suspected contaminated sites undergo various levels of investigation that focus on the potential risks that may be posed to human and ecological health under present and future land use conditions. If a site is considered to pose a potential or actual threat, it is registered as a contaminated site in the Danish Inventory of Contaminated Sites, and prioritized according to its potential impact on groundwater (drinking water protection), land use activities and surface water.
Between 1989 and 1993, the Finnish Environmental Administration undertook an extensive nationwide initiative, called the "SAMASE" project, to examine measures for and develop recommendations on the investigation, categorization and restoration of contaminated sites throughout Finland. The use of risk-based approaches was included as a specific element of the SAMASE project, particularly as it relates to the definition of contaminated soils and the protection of groundwater aquifers, which are a particularly valued ecosystem component in Finland. Despite this, and notwithstanding the guidance documents on site-specific assessment currently in preparation by the FEA, the application of risk assessment remains in its infancy, as the various stakeholders work to become familiar with the requirements of risk-based corrective action.
The application of risk assessment is relatively well established in France. Risk assessment is principally applied in a tiered manner as a means of prioritizing inventoried contaminated sites for corrective measures. Initially, a Simplified Risk Assessment (SRA) is applied to place the site in one of three risk categories, and ,if warranted, can progress to detailed risk assessment for high-priority sites. The French Ministry of the Environment, in partnership with various expert organizations, are in the process of producing technical guidance manuals for implementation of these policies.
Risk assessment in Germany is based upon the Soil Conservation Act (currently passing through the German Parliament), which is intended to harmonize national criteria for risk-based corrective action and site cleanup in concert with each federal governmentís regulations pertaining to contaminated site management. The application of risk assessment mirrors many other European countries in that, following identification of the contaminated site, a risk assessment is undertaken. To complement this approach, the Federal Ministry for the Environment, in partnership with others, is developing an exposure assessment model that provides for a land-use related exposure analysis. This will assess dose rates for certain contaminants, taking account of receptor-specific characteristics.
In Italy, contaminated sites are prioritized and managed through regional administrations within a national regulatory framework. The utilization of risk assessment as a management framework is also under the charge of the regions, and this has been supported recently through the ENEA-UNICHIM Working Group on Contaminated Soils and Groundwaters. The Working Group was set up in 1994 with the objective of defining site assessment and remediation procedures, and developing characterization and remediation technologies: risk-based corrective action was identified as a key component of these objectives. At present, a risk assessment approach based on the US EPAís RBCA methodology is being appliedóparticularly to sites regarded as high priorityóand this is being supplemented by a number of new initiatives aimed at harmonizing risk assessment practices and improving the risk assessment information base.
The Netherlands bases the prevention and remediation of contaminated soil on its Soil Protection Act. Target, limit, and intervention values have been established for soil and groundwater as part of a general framework of risk-based environmental quality objectives. Target values represent background concentrations in which risk is considered negligible. If target values are currently not met, limit values may be applied to define general concentrations which must be attained. General requirements for soil use may be established to account for local interests, and this can be backed up by a time horizon for restoration activities. Intervention values are created when "impermissible" risks occur, and these may include site specific factors.
The existing Norwegian policy on risk assessment is based on various Norwegian standards for environmental risk analysis at contaminated sites, developed under the auspices of the Norwegian Pollution Control Authority (SFT), in concert with CARACAS. The system encompasses human health and environmental components applied on a three-tiered basis (screening, simplified risk assessment, and extended risk assessment), with the emphasis placed on cooperation between regulators, industry, and the scientific community. Currently, this system is being formalized through the Norwegian project "Environmental Risk AssessmentóA decision model for assessment of polluted soil and groundwater, adapted to Norwegian conditions," which draws its framework primarily from the CARACAS project. The most significant advance has been made with the Chemical Hazard Assessment and Risk Management (CHARM) software model, developed and applied for use in the oil industry.
Under the direction of the Spanish Ministry of Public Works, Transportation, and Environment in 1991, a National Inventory on Contaminated Sites was initiated. The principle goals of this objective were to identify and characterize "worst case" contaminated sites and to prioritize each site through comparison and options of cleanup methods. The risk associated with each site is established by determining the relative threat an impacted site poses both on and off-site through factoring items such as the intensity and duration of the contaminant, toxicity, subsurface characteristics, and land use issues. Final prioritization is determined by combining both onsite and offsite priorities, and cost effectiveness.
In 1995, the Swedish EPA formalized a remediation action plan to establish long-term direction of site remediation work, and set feasible goals over a five-year period. A country-wide inventory of contaminated sites was produced by the Swedish EPA and county administrative boards. These boards and the municipalities are responsible for the practical implementation of remediation. The EPA develops methods and recommendations for risk assessments and will oversee assessments made by the local authorities. The Swedish EPA risk assessment methods focus on present and future situations and include the evaluation of contaminant toxicity, concentration, location and conditions, and the protective value and sensitivity of the surrounding areas. The Swedish remediation action plan is summarized in the report (in English), Weíre Well on the Way (Naturvardsverket, 1995).
Risk assessment practices in the UK have been promoted both by the Environmental Agency (EA) in England and Wales, and the Environment Protection Agency in Scotland. Risks are estimated to prioritize sites using the source-pathway-receptor concept and evaluated through comparison with generic values or by models that accommodate site-specific characteristics. The Ministry of Environment has developed guidance on risk assessment methodology for assessing contaminant impact on groundwater and a Contaminated Land Exposure Assessment Model (CLEA) with associated guideline values. They have also designed statistically defensible sampling strategies as well as collected research on toxicological effects. The Environmental Agency has established a research program relating to the aims of contaminated land remediation, and the Research Councils, Construction Industry Research and Information Association (CIRIA) and other government-industry funding initiatives are all contributing to the development of contaminated land risk assessment.
The attitudes towards contaminated site management of the 15 member states of the European Union (EU) are particularly interesting in view of the imminent expansion of the EU eastwards, to include the highly-polluted countries of Poland, Hungary and the Czech Republic. It will be interesting to see whether the thorny non-technical issues associated with the risk-based approach, particularly those relating to residual liability, will also be exported and, if so, how they will be managed. It is to be hoped that by enhancing our understanding of risk assessment practices abroad, we might be able to bring home a message that will encourage the wider use of RBCA-type approaches and rejuvenate the contaminated land redevelopment industry here in North America.