Summary

Description

During the summers of 1996 and 1997, the U.S. Fish and Wildlife Service, New Mexico Ecological Services Field Office collected 139 biologic and substrate samples, and 27 filtered water samples for a variety of inorganic and organic chemical analyses. Our objectives were to identify chemicals in the environment that may reduce reproductive success of interior least terns, and provide baseline contaminant data at Bitter Lake National Wildlife Refuge Refuge in southeastern New Mexico. We analyzed water, sediment, and biota for inorganics, aliphatic hydrocarbons, polycyclic aromatic hydrocarbons PAH, polychlorinated biphenyls PCB, and organochlorine insecticides. Aluminum, cadmium, lead, selenium, and mercury concentrations were elevated in water samples when compared to regional averages. Aluminum, boron, mercury, selenium, and zinc were the only elements in plants, invertebrates, fish, or eggs that exceeded literaturebased thresholds for adverse health effects. Lake St. Francis contained biota that had greater concentrations of copper, selenium, and zinc than at other sites, although sediment metal concentrations were low. Hunter Marsh, which historically received municipal wastewater, contained sediment and biota with elevated concentrations of lead and mercury. No organic chemicals were detected in water, but several organics were found in sediments from the mouth of Lost River at Bitter Creek and in Hunter Marsh, and in fish collected at Hunter Marsh. The remaining areas of the Refuge were relatively contaminant free. Although PCBs and organochlorines were not measured in Lost River sediments, fish contained only trace concentrations of these compounds. Several PAHs were measured in sediments in Hunter Marsh at concentrations as high as 20 mgkg dry weight parts per million, ppm, which could adversely impact invertebrate communities and wildlife that forage there regularly. Fish from Hunter Marsh also contained total PCBs at concentrations up to 5 ppm dry weight. A diet that contains greater than 0.1 ppm total PCBs can have adverse effects on wildlife. Hunter Marsh contains contaminated sediments, invertebrates, and fish that when consumed regularly by local wildlife could result in adverse health effects. Additional sampling is required in Hunter Marsh to determine the extent of contamination, and if remedial action is warranted.