Todd Engineers: Santa Clarita

Hydrogeologic Assessment of
Perchlorate Contamination
Santa Clarita Valley
Los Angeles County, California

Five municipal water supply wells located in the Santa Clarita Valley have been found to be contaminated with perchlorate, a toxic chemical associated with the manufacture of fireworks, explosives, and munitions.

Perchlorate had historically been used in large quantities at a nearby former manufacturing facility known as the Whittaker Corporation Bermite Facility. Environmental investigations at the Whittaker site found perchlorate in onsite dumps, incineration areas, wastewater, soil, sediment, surface water, and groundwater.

Key Issues
Five municipal water supply wells shut down due to perchlorate contamination Water companies sue former missile and munitions manufacturer Todd Engineers retained to assess perchlorate sources

Several water purveyors operating in the area filed suit against the Whittaker Corporation and the current property owners for damages related to perchlorate contamination in the water supply wells. Todd Engineers was retained by the water agencies to provide expert opinions regarding the causes, mechanisms, and future impacts of the perchlorate contamination.

Todd Engineers reviewed operational and environmental data available for the Whittaker site, environmental data regarding other potential responsible parties, as well as regional hydrogeologic information. Todd Engineers concluded that perchlorate contamination found in the offsite water supply wells was caused by the migration of perchlorate from the Whittaker site.

Services Provided
Assessed perchlorate sources, transport, and fate Prepared expert report Provided deposition testimony Developed strategies for containment Presented study results to government and regulatory community

The data indicate that multiple mechanisms and pathways are acting to transport perchlorate from the Whittaker site to downgradient supply wells. In brief, surface water transports the perchlorate downstream of the site where it can percolate to groundwater. Perchlorate is also transported downward through the soil column where it can enter the groundwater system directly below the site. Dissolved perchlorate then migrates downgradient through permeable subsurface strata.

Surface Water Pathway
Groundwater Pathway

Perchlorate
Recently detected in a number of water supply wells across California Toxic at low concentrations Highly soluble and mobile - capable of forming significant groundwater plumes Stable in groundwater systems - can persist for decades Difficult to remediate with current technology