Yates Environmental Sciences Inc.
Case Studies
Screening- Level ERA For Tidal Wetland Mitigation Site
Metals and polycyclic aromatic hydrocarbons (PAHs) were detected in sediment samples above ecological screening benchmarks at a prospective tidal wetland mitigation site sampled killifish (Fundulus heteroclitus) and ribbed mussels (Geukensia demissa), supplementing the data with measurements of organic carbon and AVS/SEM. The AVS/SEM results identified two predominant geochemical regimes on-site: a sulfidic (anaerobic) and an organic-driven (aerobic) community, in which metals bioavailability would be limited by sulfide and organic carbon, respectively. Equilibrium partitioning modeling indicated limited bioavailability, and site-specific tissue data agreed with the results of the desktop models. Food chain modeling was used to compare pre-construction vs. post-restoration risks. Based on these lines of evidence it was determined that restoration could proceed safely with no adverse ecological risks.
Illegal Fill in a Floodplain
Was contracted to perform an ERA at a Site where fill material had been illegally deposited to a floodplain, resulting in severe contamination. First, wildlife game cameras were installed to identify indicator species, site-specific exposure pathways and delineate the food web. Small mammal sampling was conducted under state scientific collecting permits, focusing on the white-footed mouse (Peromyscus leucopus) a common and widespread omnivore. Mice were examined for abnormalities, euthanized, dissected, and specific organs measured for lead contamination. Results were used to evaluate the health of the mouse population and that of predators that feed on mice. Earthworm tissue sampling and food chain modeling identified high risks of lead to ground-feeding songbirds, so the model was used to back-calculate a clean-up goal that would eliminate lead “hot spots” while leaving the remainder of the habitat intact.
Redevelopment of Hudson River Brownfield
Was contracted to conduct an Ecological Evaluation and assist in redevelopment of a Brownfield along the Hudson River. Aside from an off-Site groundwater plume migrating onto the property, the property had site-wide historic fill and EPH in shallow groundwater. The property boundary extended *into* the Hudson River prompting sediment sampling for historic fill contaminants and EPH. After meeting with the NJDEP, several sediment borings were advanced and analyzed for these contaminants. YES leveraged existing sediment data for the Hudson River collected by NOAA, USEPA and others saving the client tends of thousands of dollars in investigation costs. The background results were comparable to site-adjacent sediments and given the lack of EPH, no further action was warranted.
ERA of Contaminated Groundwater to Wetlands and Vernal Pools
Was conducted an ecological risk assessment of chlorobenzene and ammonia-contaminated groundwater migrating to a former Atlantic white cedar bog, Phragmites wetlands and vernal pools across a >130-acre property. Pore water sampling was used to delineate the contaminants to NJDEP Ecological Screening Criteria, and samples were submitted for plant and amphibian (FETAX) toxicity testing. Oxidation of shallow groundwater, either through Phragmites roots or hyporheic exchange with vernal pools, detoxified ammonia and enhanced natural attenuation of chlorobenzene. Amphibian community surveys were used to map out breeding populations, compare metrics (e.g., % deformities, body weights, male/female ratios) and identify impaired communities. Based on these surveys, natural detoxification processes of shallow groundwater, and the lack of habitat in highly acidic/reducing peat bogs it was determined the groundwater does not pose an ecological risk.
Mountainside Landfill
Conducted an Ecological Evaluation for a de facto landfill that was created via illegal dumping years ago by a predominant manufacturer in the area. Primary contaminants of ecological concern were heavy metals but the majority were excluded using food chain modeling. Earthworm tissue sampling was conducted on-Site and the results plugged into the models. By combining site-specific data with adjusted exposure factors it was determined that risks were negligible. The NJDEP reviewed the EE, submitted comments which were subsequently discussed, we responded to said comments and the NJDEP agreed with our finding of no further evaluation.
