Broadbent has provided a full suite of environmental consulting services to the State of Nevada, Division of Environmental Protection (NDEP), Bureau of Corrective Actions (BCA) through the Environmental Mitigation, Assessment, and Remediation (EMAR) contract, since 2006. Broadbent was awarded the EMAR contract, through a competitive proposal process, from 2006 – 2010, 2010 – 2014, 2014 – 2018, 2018 – 2022, and again from 2022 – 2026. As part of the EMAR contract, overlapping multiple contract periods, Broadbent was tasked with public notification and characterization and mitigation of tetrachlorethylene (PCE) vapor intrusion into a residential neighborhood in Southern Nevada. Broadbent has worked closely with NDEP staff to inform residents of the potential PCE vapor intrusion issue, sample collection process, and the indoor air PCE mitigation system process by preparing public outreach letters, contacting individual residents, and participating in public outreach forms.
Characterization activities included coordinating sample collection from over 95 residences and two area schools, performing individual home source surveys to determine sample collection points, and collection of 24-hour PCE indoor air samples utilizing Summa canisters from each of these residences. Indoor air samples collected from ten individual homes indicated PCE concentrations in excess of the NDEP PCE action level and required indoor air PCE mitigation. Mitigation activities included management of individual home mitigation system pilot testing, sub-slab depressurization (SSD) system design, SSD system permitting, management of installation activities associated with ten SSD systems, post mitigation indoor air PCE confirmation sampling, and management of SSD system optimization activities.
Additional project tasks included preparation of a public outreach and data management Work Plan, preparation of an indoor air sampling and analysis Work Plan, preparation of initial indoor air sampling reports, preparation of an individual home SSD pilot testing Work Plan, preparation of individual indoor air mitigation system designs, maintenance of site data, and preparation of a post mitigation report. Currently, the ten indoor air mitigation systems remain in operation. Residents periodically notify NDEP of problems with individual indoor air PCE mitigation systems, at which point Broadbent conducts system inspections to trouble shoot issues and maintain the system within the designed operational parameters.