Applications of Tri-National Project Data to Human and Ecological Risk Assessment

The need for baseline soil geochemical data to effectively assess and manage natural resources and the risk of environmental hazards is well recognized. One particular application of such data is to compliment the ecological and human health risk assessment processes and to support mitigation efforts as needed. In addition to the chemical analyses done as part of Tri-national Project core protocol, additional samples were tested for soil toxicity to provide a biological aspect to the interpretation of the standard geochemical data. Samples for this ecotoxicological study were collected as part of the Tri-national Project and also other surveys undertaken in the Atlantic Region within the past 4 years. The resulting data is collated in a GIS-based database. A key purpose of this research is to provide risk assessors with additional data to incorporate into their risk model calculations, further strengthening the scientific validity of the risk assessment process.

Additionally there was collaboration between EC-Atlantic staff and other Tri-national survey participants to compare protocols for sample collection and analyses. Samples were gathered and analyzed using different methodologies, thereby allowing comparisons of data from the following: discrete samples vs. composite samples; horizon-based vs. depth-based samples (includes 0-30 and 30-45 cm intervals); and various analytical procedures involving total and partial extractions. Field sampling was undertaken between June and September 2007 resulting in the collection of approximately 175 samples from Nova Scotia and New Brunswick. These samples have been analyzed for metals, polycyclic aromatic hydrocarbons (PAHs), total organic carbon, pH, and grain-size distribution. In addition, bulk soil samples were collected at 30 sites for the purposes of toxicological testing.