Fingerprinting Contaminants Through the Food Web
TIG Environmental personnel investigated sources of contamination in the food web for a European industrial client to determine whether traces of contaminants in food products had originated from the client’s facility. For more than four decades, the facility had operated near neighborhoods and farms. Previous claims stated that contaminants from the facility had migrated through the air to soil or pasture plants, grazing animals, and into cheese and milk. The indirect transmission route required multiple specialized analyses to reach conclusions that bore a high degree of confidence.
We designed a sampling plan to facilitate chemical fingerprinting of potential emission sources, then sampled and analyzed pasture land adjacent to the client’s site. Our chemical, biological, forensics, statistics, and data experts performed a polytopic vector analysis on air, soils, and animal tissues from the region. The forensic analysis examined the unique chemical fingerprints of PCBs, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and mercury isotopes. The chemical fingerprint and isotopic ratio comparisons were performed on soil, pine litter, and pasture grass samples. The analysis included comparisons to contaminants in the ambient air and soil of about 70 cities to determine potential sources of emissions.
The results ruled out the industrial client as the primary source of PCBs, PCDDs, PCDFs, and mercury in the region’s soils and pointed to other potential alternative sources as more likely.