Authors:
Katy Baker | ARCADIS EC Harris | United Kingdom
Debanjan Bandyopadhyay | SENES Consultants India Pvt. Ltd., ARCADIS | India
Aurelie Blusseau | Arcadis ESG | France
Pawel Goldsztejn | ARCADIS Sp. z o.o. | Poland
Lien Heynderickx | ARCADIS Belgium nv | Belgium
Patricia Iezzi | ARCADIS Logos | Brazil
Francesco Ioppolo | ARCADIS Italia | Italy
Joe Jiao | ARCADIS EC Harris | China
Ragna Jansen | ARCADIS Netherlands | Netherlands
PhD Christian Niederer | BMG Engineering AG | Switzerland
Harriet Phillips | SENES Consultants, ARCADIS | Canada
Greet Schrauwen | ARCADIS Deutschland GmbH | Germany
Tamar Schlekat | ARCADIS U.S., Inc | United States
The use of risk assessment to assist in management of contaminated sites is becoming common practice across the globe. However, significant variability is still observed as a result of its application (e.g. due to differing legislative regimes), both in how risk assessment is implemented and to what extent it is being used to aid sustainable decision-making. This presentation will review the state of play across the globe, including Europe, North America, Latin America and Asia, grouping and mapping countries and regions based upon which ‘tier’ of risk assessment is most commonly used to determine requirements for remediation. The data will then be evaluated to assess whether the use of risk assessment as a decision-making tool is assisting in the sustainability agenda, or in fact resulting in less sustainable approaches being adopted for management of contaminated sites. The hypothesis that the most sustainable management solutions for contaminated sites arise from those countries or regions using higher tier risk assessment practices to determine remediation requirements will be explored.
The concept of ‘tiered’ risk assessment is well recognised globally; four tiers of risk assessment have been defined, although it is acknowledged that the definitions vary between countries:
Tier 1: Problem conceptualisation
The first tier of assessment comprises definition and structuring of the problem, and identification of potential risks, using qualitative methods of assessment.
Tier 2: Filtering Sites
The second tier of assessment focuses on evaluation of contaminated sites using conservative screening levels. When used effectively, this results in confidence as to which sites do not require remediation, and highlighting those for which further consideration is appropriate. Conversely, where misapplied, this can instead result in identification of contaminated sites requiring remediation, and use of conservative screening levels as remediation endpoints.
Tier 3: Site Specific Evaluation of Risks
The third tier of assessment is aimed at reducing uncertainty in the risk evaluation process, typically combining lines of evidence gained through both modelling and measurement. However, the outcome of a Tier 3 risk assessment is, in many cases, still a predicted rather than measured effect.
Tier 4: Significance Testing
The final tier of assessment looks to test whether the predicted effects are occurring, or could reasonably be expected to occur. This concept also known as ‘cause-attribution’ evaluation is most widely applied in evaluation of risks to ecological receptors. It is more occasionally applied for the assessment of risks to human health, for example detailed exposure and response modelling for contaminants in indoor air.
An evaluation will be made as to how the global progression from use of Tier 2 assessments to use of Tier 3 and Tier 4 assessments to determine remediation needs is improving the value of risk assessment in helping with more sustainable decision-making for the management of contaminated sites. The focus of the presentation will be on specific countries identified from the global review as examples in practice. This will include countries where policy shifts are underway (Poland) or under discussion (Germany), and countries where Tier 3 and 4 assessments are already routinely used to guide management of contaminated sites.