Ecological Risk Assessment


Passive Remediation Systems Inc. (PRSI) team of ecotoxicologists regularly supports federal, provincial and private-sector clients by providing site-specific ecological risk assessments of contaminated properties, and establishing target clean-up levels for site-specific contaminants in media such as soil or sediment. Our work involves the application of established protocols to quantify potential risk to ecological receptors, including terrestrial and/or aquatic plants, invertebrates, birds, mammals, fish, reptiles and amphibians, on a site-specific basis. These estimates are then used to back-calculate target clean-up levels of contaminants tailored to the level of sensitivity of ecological receptors at the site.

PRSI Ecological Risk Assessment services include:

  • Supplemental investigation (to obtain data to fill data gaps, post-ESA work)
  • Biological inventory
  • Plant sampling
  • Background sampling
  • Delineation sampling
  • Indoor air vapour sampling
  • Human Health Risk Assessment
  • Food-web modelling (exposure calculations and hazard/risk quotients
  • Risk-based site-specific target levels calculations (soils, sediments, groundwater)
  • Contamination delineation
  • Remedial options assessment
The PRSI approach follows federal and provincial protocols, and includes:
  • Review of site historical data and environmental studies
  • Assessment of data quality, and compilation of chemical data from multiple sources to form a complete data set
  • Application of appropriate regulatory guidelines to screen and identify contaminants of potential concern
  • Compilation of biological inventories on the basis of existing data or by conducting a site survey
  • Identification of species at risk that could plausibly use the site
  • Identification of measurement receptors, to be used in site-specific food-web modelling, based on local ecology
  • Assessment of pathways by which receptors may be exposed to contaminants
  • Development of Ecological Conceptual Site Models
  • Estimation of exposure of each receptor to each contaminant, by application of established and appropriate transfer factors
  • Development of toxicity reference values that reflect tolerable levels of exposure protective of each modelled receptor
  • Quantitative risk characterization
  • Back-calculation of site-specific target levels for clean-up
  • Documentation of uncertainties and data gaps.

Site contamination can then be delineated on the basis of risk-based site-specific target levels. Depending on the sensitivity of site-specific receptors, this approach may result in reduced volumes of site media for clean-up, or may allow the selection of a risk-management approach rather than more intrusive measures.

Contact us and learn more about our Ecological Risk Assessment services.