Human Health and Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory Volume 1: Report of Results

Human health and ecological risk assessments are required as part of the Resource Recovery and Conservation Act (RCRA) permit renewal process for waste treatment units. This risk assessment is prepared in support of the RCRA permit renewal for the Explosives Waste Treatment Facility (EWTF) at Site 300 of the Lawrence Livermore National Laboratory (LLNL). The human health risk assessment is based on U.S. Environmental Protection Agency- (U.S. EPA) approved emissions factors and on California Environmental Protection Agency (CalEPA), California Air Resources Board (CARB) and U.S. EPA assessment and air dispersion models. This risk assessment identifies the receptors of concern and evaluates theoretical carcinogenic risk, and theoretical acute and chronic non-carcinogenic hazard, following those guidelines. The carcinogenic risk to a 30-year resident at the maximum off-site receptor location is 0.0000006 or 0.6 in 1 million. The carcinogenic risk to a 25-year worker at the maximum bystander on-site receptor location is also 0.0000006 or 0.6 in 1 million. Any risk of less than 1 in a million is below the level of regulatory concern. The acute non-carcinogenic hazard for the 30-year resident is 0.01, and the chronic non-carcinogenic hazard is 0.01. The acute non-carcinogenic hazard for the 25-year worker is 0.3, andmore » the chronic non-carcinogenic hazard is 0.2. The point of comparison for acute and chronic non-carcinogenic hazard is 1.0; an estimate less than 1.0 is below the level of regulatory concern. The estimates of health effects are based on health conservative assumptions and represent an upper bound of the possible exposures to the receptors. Based on these results, emissions from the operations of the EWTF should not be of concern for human health. For the ecological risk assessment (ERA), 10 receptor species (including plants), representing members of the trophic levels in the habitat of Site 300, were evaluated for the possibility of potential detrimental effects from EWTF emissions. The ecological hazard quotients (EHQs) at a location closest to the EWTF suggest a potential for adverse consequences. However, the conservatisms incorporated into the analysis may overestimate potential consequences and may explain the potential for impacts. Using less conservative values suggests that there is a possibility for limited to no additional impact to occur from the continuing operation of the EWTF.« less