LAS VEGAS–The Nevada Division of Environmental Protection (NDEP) is arranging in-home meetings with 146 homeowners in a residential area east of the Boulevard Mall to check the indoor air in their homes for the presence of a common solvent used in dry cleaning.
The NDEP suspects that the solvent, perchloroethylene or PCE, was discharged into the shallow groundwater from a former dry cleaner, located at 3661 South Maryland Parkway in the Maryland Square Shopping Center. The investigation continues into other possible sources of the contamination and any other associated responsible parties.
Groundwater monitoring data indicate that, over time, the PCE has migrated eastward in the shallow groundwater underneath the Boulevard Mall and some residences in the neighborhood east of the Mall. The NDEP is offering to test the indoor air in the homes to see if vapors from the underground PCE plume are making their way into the homes. The tests are voluntary and free-of-charge to the homeowners.
According to the NDEP, the shallow groundwater moves slowly through the soil about 10 to 20 feet below the ground surface. Results of computer simulations using groundwater data indicate that the PCE may be evaporating from the contaminated groundwater, and that the vapors could be making their way to the surface and seeping through cracks in the concrete slab foundations of some of the homes.
“There is no immediate health concern,” said Jim Najima, chief of NDEP’s Bureau of Corrective Action. “We’re taking these precautionary measures to make sure that no long-term health concerns arise.” Najima also emphasized there is no danger to patrons and employees of the Boulevard Mall, and the soil in the neighborhood and the drinking water are safe. Drinking water for Las Vegas comes from the Las Vegas Valley Water District, which does not use the shallow groundwater as a water-supply source.
Najima said concentrations of PCE vapor in most homes are unlikely to exceed EPA’s health-protective levels, but the only way to be sure is to test the indoor air. He noted that EPA’s health-protective levels are calculated based on continuous exposure for 24-hours-per-day, seven-days-per-week for 30 years or more.
The NDEP has sent personal letters to each of the 146 homeowners/residents in the affected area offering to meet with them, explain the situation, and arrange for the indoor air monitoring. If, after the one-day monitoring, PCE vapors are found in any of the homes in excess of EPA health-protective standards, a mitigation system can be installed to alleviate the problem almost immediately.
The NDEP will have two-person teams visiting the homes by appointment, and expects to complete all the visits and the indoor testing by the end of October.
“Every time you bring clothes home from the cleaners, you may bring a small amount of PCE into your home,” Najima added. “It’s a solvent that’s pretty commonly found in the environment. We just want to make sure that these underground vapors are not seeping into these homes and degrading the indoor air quality.” He noted that besides dry-cleaned clothes, PCE is found in some auto parts solvents, hobby craft adhesives, spray polishes, spot removers, plumbing adhesives and some lubricants.
He explained that once all the potential responsible parties are identified, they will be held accountable for paying the costs of the investigation and cleanup. NDEP will also require those parties to pay for the installation of a remediation system west of the neighborhood to clean up the groundwater before it flows under the residential area.