Mercury in Fish Collected Upstream and Downstream of Los Alamos National Laboratory, New Mexico: 1991--2004.

Abstract

Small amounts of mercury (Hg) may exist in some canyon drainage systems within Los Alamos National Laboratory lands as a result of past discharges of untreated effluents. This paper reports on the concentrations of Hg in muscle (fillets) of various types of fish species collected downstream of LANL's influence from 1991 through 2004. The mean Hg concentration in fish from Cochiti reservoir (0.22 {micro}g/g wet weight), which is located downstream of LANL, was similar to fish collected from a reservoir upstream of LANL (Abiquiu) (0.26 {micro}g/g wet weight). Mercury concentrations in fish collected from both reservoirs exhibited significantly (Abiquiu = p < 0.05 and Cochiti = p < 0.10) decreasing trends over time. Predator fish like the northern pike (Esox lucius) contained significantly higher concentrations of Hg (0.39 {micro}g/g wet weight) than bottom-feeding fish like the white sucker (Catostomus commersoni) (0.10 {micro}g/g wet weight).