Former Trap Club Investigation & Risk Assessment

Northern California

JJ&A completed a site assessment at a former trap club in Northern California. The site was used as a shooting range from the 1950s until 2004. Clay targets containing PAHs were thrown from the trap houses in a fan-shaped pattern. Lead shot, shell debris composed of plastic, paper, and metal caps, and clay target fragments were found at the site. The debris field from clay targets lay between the shooting stations and the shot-impacted area, with some overlap between them. Based on range estimates for typical trap shot gun loads provided in Interstate Technology and Regulatory Council (ITRC) guidance, shot was predicted to lie up to 770 feet down range of the shooting stations.

The assessment was considerate of the ITRC guidance and the USEPA’s Triad Approach for the evaluation of Brownfield sites. Because the area of impact was large (several acres), diffuse at the boundaries, and spotty in some areas, a flexible and observation-driven approach allowed field screening to guide the investigation. A sampling grid was designed to focus sample collection within the predicted impact area and its periphery (i.e., sides and “down range”, where the impact was predicted to taper off). Samples were collected at 6 inch depth intervals to accurately quantify the volume of impacted soil for remedial planning purposes. The actual impacted area was found to be remarkably consistent with the ITRC-predicted impact area.

A site-specific ecological risk assessment is being performed to calculate a screening level that takes into account soil pH, organic matter content, and habitat ranges of local sensitive species.

The client recently decided to go forward with remedial action, and JJ&A will be providing removal action work plan and implementation services.