Risk Assessment: Major Rail Yard

New York City

Multi-media (soil, groundwater, free product, sewer water/sediment) data collected during a multi-phased remedial investigation at a major railroad yard site in New York City were used to prepare a risk assessment that estimated potential risk to humans associated with exposures to PCBs and other chemicals at the Site.

The risk assessment characterized chemicals of potential concern, possible exposure pathways, and populations that were potentially exposed. Historical employee service information was used as part of the exposure assessment.

Exposure scenarios included occupational exposures to railroad employees and contract construction workers involved in soil disturbance and subsurface activities.

Reasonable maximum exposed individual (RMEI) and Monte Carlo simulations were conducted to investigate different exposure conditions.

Based on site-specific health protective assumptions in the exposure assessment, dermal contact was the most important primary exposure pathway for the chemicals of concern. However, existing barrier protection (PPE) rules at the site (overboots, gloves, tyvek) were determined to preclude any significant risk to workers during the disturbance of the subsurface media.

To be protective of workers’ health, Roux Associates derived site-specific cleanup levels for PCBs. The risk assessment ascertained that a PCB cleanup level of 69 ppm was acceptable for the site. This concentration is significantly higher than the generic cleanup standards recommended by NYSDEC.

Roux Associates' exposure assessment was considered to be an important tool in enabling the client to save $80 million in cleanup costs at the site.