San Bernardino National Wildlife Refuge Well 10

Abstract

The U.S. Geological Survey (USGS), at the request of the U.S. Fish and Wildlife Service, evaluated the water production capacity of an artesian well in the San Bernardino National Wildlife Refuge, Arizona. Water from the well initially flows into a pond containing three federally threatened or endangered fish species, and water from this pond feeds an adjacent pond/wetland containing an endangered plant species. USGS received a source license from the U.S. Nuclear Regulatory Commission (NRC) for the radioactive (24'Am-Be) source used in a neutron emission/detection tool commonly used in well Ioggings of this type. The source was inadvertently lost in the well in 1986; and after several unsuccessful attempts to retrieve the source, the USGS has requested that the Am-Be source license be terminated and has attempted to seal the source in place with cement as required by NRC license termination regulations. Because of uncertainties related to the condition of the stainless steel source container, the effectiveness of a cement plug already installed, and concerns about the potential for future contamination, NRC decided to prepare this environmental assessment to analyze the potential water quality, ecological, and human health impacts of three alternatives for final disposition of the Am-Be source: (1) the proposed action, abandonment in place; (2) Am-Be source retrieval; and (3) the no-action alternative. The assessment found that the proposed action would result in no significant water quality or human health impacts and would produce only temporary and minor ecological impacts associated with emplacement of the cement plug. The source retrieval alternative-under a worst case scenario-could result in adverse impacts (radiation) on the three fish species of concern. The no-action alternative would be unlikely to produce significant adverse impacts but would require continued monitoring to ensure that unexpected contaminant concentrations do not occur in water or pond sediment.