USGS report on mercury in streams makes waves

The United States Geological Service released a new report this week – Mercury in Fish, Bed Sediment, and Water from Streams Across the United States, 1998–2005 which has generated some sobering headlines: "Mercury Found in Every Fish Tested, Scientists Say," "Streams across U.S. tainted with mercury" and more.

The study notes: "Slightly more than two-thirds of the sampled Hg sites were in the eastern half of the United States compared with the western half (west of the Mississippi River)." However, western river leaders will be interested in the findings because the study areas included several large areas in the Intermountain West. Specifically, atleast part of nine of the reconnaissance study areas were in our region. See http://water.usgs.gov/nawqa/mercury/ for a map of the watersheds studied.

A few excerpts from the report may inspire you to dig deeper:

• "Fish-Hg concentrations at 27 percent of sampled sites exceeded the U.S. Environmental Protection Agency human-health criterion of 0.3 micrograms per gram wet weight. Exceedances were geographically widespread, although the study design targeted specific sites and fish species and sizes, so results do not represent a true nationwide percentage of exceedances." (page 1)

• "The highest THg concentrations in fish were from blackwater coastal-plain streams draining forests or wetlands in the eastern and southeastern United States, as well as from streams draining gold- or Hg-mined basins in the western United States (1.80 and 1.95 micrograms THg per gram wet weight, respectively)." (page 1)

• "Hg concentrations in fish at most sites (71 percent, 208 of 291 sites) exceeded the value of 0.1 μg/g THg (ww) that is of concern for the protection of fish-eating mammals, including mink and otters (fig. 6; Yeardley and others, 1998; Peterson and others, 2007). Concentrations at 27 percent of the sites (79 of 291) exceeded 0.3 μg/g THg ww in fish. As mentioned earlier, most of the Hg found in fish tissue is MeHg (Huckabee and others, 1979; Grieb and others, 1990; Bloom 1992), and a concentration of 0.3 μg/g MeHg ww in fish is the USEPA MeHg criterion for the protection of human health (U.S. Environmental Protection Agency, 2001, 2009)" (page 27)

• Although some of the highest levels were found in "blackwater" streams in the southeast, elevated mercury levels in fish also are found in streams of the western U.S. that are affected by mining of mercury or gold.

Coverage around the region and beyond

• The New York Times wrote Mercury Found in Every Fish Tested, Scientists Say

• The Los Angeles Times said Streams across U.S. tainted with mercury

• The Salt Lake Tribune wrote Great Salt Lake stands out – for mercury pollution despite the fact the Lake was not part of the study. The article notes "…the Utah water body typically has mercury levels double those found in more than 90 percent of the water sampled nationally. And the open water has up to 38 times more methyl mercury than 97 percent of waters sampled in the survey, while a recent sample taken in the Great Salt Lake wetlands had more than six times as much as in 97 percent of the sampled waters. "