Prioritizing Remediation through Risk Assessment | Golder
Geological Survey Sweden
Services (Technical Disciplines):
The surveys (performed by sub-contractors) included analysis of DDT levels in soil and earthworms (chemistry LOE), effects on reproduction of earthworms and springtail insects (toxicology LOE), and the carbon and nitrogen mineralization and species composition of earthworms, springtails and roundworms (ecology LOE).
Project Objectives/ Outcomes:
The results showed insignificant risk of negative impacts on the soil ecosystem function (excluding hot-spots), and the assessed livestock, birds and larger mammals. The risk was also assessed to be insignificant for residents or visitors under the current circumstances. Although a theoretical risk exists for small mammals and children at certain circumstances if consumption habits changes compared to today. Further investigations are, however, needed to assess if there is an actual risk.
This project confirmed that the TRIAD method is appropriate for assessing the site-specific risks to soil ecosystem function posed by the prior use of DDT at the site. However, a suitable reference area or good concentration gradient is required. The quantitative evaluation method is considered useful for prioritizing risks between areas, while the qualitative method is useful to determine if there is a level of risk or not.
The results from this project will be evaluated against other contaminated forest nurseries.
The Geological Survey of Sweden engaged Golder to carry out a site-specific environmental (soil and aquatic ecosystem, wildlife, livestock) and health risk assessment in accordance with the Swedish Environmental Protection Agency’s risk assessment guidance at the Kårehogen site. The assessment used the TRIAD method (ISO 19204:2017(E)) to assess the site-specific risks of the soil ecosystem. The use of the TRIAD method as a tool for prioritizing remediation among contaminated former plant nurseries was also evaluated.
The TRIAD is based on the chemistry, (eco)toxicology and ecology lines of evidence (LOE). The purpose is to assess if there is a link between the concentration and toxicity of the contaminant and ecological outcomes.
To investigate whether the soil ecosystem in Kårehogen was negatively affected by DDT, Golder compared on-site results to a reference area. The results for the various LOEs including the results of statistical analyses were evaluated through a qualitative method (cause-effect analysis) and a quantitative method (risk index calculations).
Geoscience Ireland Contact:
Markus Kappling (firstname.lastname@example.org)