revised final - Agency for Toxic Substances and Disease Registry ...

MERCURY 416
5. POTENTIAL FOR HUMAN EXPOSURE
sediment samples from the Lake Roosevelt/Upper Columbia River in Washington State were found to
contain up to 2.7 µg/g (ppm) mercury (Johnson et al. 1990). Mercury concentrations in sediments up to
28 cm in depth in lakes adjacent to coal-fired power plants near Houston, Texas ranged from 255 to
360 mg/kg (ppm) in the summer and from 190 to 279 mg/kg (ppm) in the winter (Wilson and Mitchell
1991).
Surface sediments taken from Canadian lakes receiving atmospheric input from smelters contained
between 0.03 and 9.22 µg/g (ppm) mercury, with the highest values being found in lakes nearest the
smelters. However, sediment concentrations were not correlated with mercury concentrations in fish from
the lakes; the fish concentrations ranged from 0.003 to 0.88 µg/g (ppm), with the highest concentration
found in fish from one of the least contaminated lakes (Harrison and Klaverkamp 1990).
Estuarine and coastal marine sediment samples analyzed for NOAA's National Status and Trends Program
between 1984 and 1987 showed that 38 of 175 sites contained mercury concentrations in excess of
0.41 µg/g (ppm) (dry weight) (O'Connor and Ehler 1991). In addition, mercury sediment concentrations
at 6 sites exceeded the NOAA ER-M concentration of 1.3 ppm (dry weight), which is the concentration
determined to be equivalent to the median (50th percentile) for all sites monitored. These 6 sites included
5 sites in the Hudson River/Raritan Estuary, New York Bight, and Raritan Bay areas between New York
and New Jersey (ranging from 1.6 to 3.3 ppm dry weight) and one site in the Oakland Estuary in
California (2.3 ppm dry weight) (NOAA 1990). Sediments taken from coastal areas off British Columbia,
Canada contained concentrations of mercury ranging from 0.05 µg/g to 0.20 µg/g (ppm), while mercury
concentrations in fish from these waters were only slightly higher; bioconcentration factors ranged from
less than 1 to 14 (Harding and Goyette 1989).
Mercury has been identified in soil and sediment samples collected at 350 and 208 sites, respectively, of
the 714 NPL hazardous waste sites where it has been detected in some environmental media (HazDat
1998).
5.4.4 Other Environmental Media
Foods. The U.S. Food and Drug Administration (FDA) conducted a Total Diet Study (April 1982 to
April 1984) to determine dietary intakes of selected industrial chemicals (including mercury) from retail
purchases of foods representative of the total diet of the U.S. population (Gunderson 1988). The data were
collected as part of 8 food collections, termed “market baskets”, collected in regional metropolitan areas