Mercury in Wisconsin rivers: Results of background trace metals study
- Wisconsin Dept. of Natural Resources, Monona, WI (United States)
- Univ. of Wisconsin, Madison, WI (United States). Water Chemistry Program
Forty-one river sites in Wisconsin were analyzed of low-level mercury. Thirty-four of these sites were primary ``indicator`` sites and 7 were ``integrator`` sites. Indicator sites were chosen as Relatively Homogeneous Units (RHUs) that reflected watershed differences in geological character, soil type, land use patterns and anthropogenic influence. In Fall 1992 (low flow), unfiltered total mercury (Hg{sub T}) ranged from 0.7 to 10 ng L{sup {minus}1} while filtered Hg{sub T} ranged from 0.3 to 7.4 ng L{sup {minus}1} for all sites. In Spring 1993 (high flow), unfiltered Hg{sub T} ranged from 2.2 to 42.7 ng L{sup {minus}1} while filtered Hg{sub T} ranged from 0.8 to 24.2 ng L{sup {minus}1}. RHU groupings showed substantial differences in Hg levels. Urban sites showed the greatest variability between Fall and Spring, as mean unfiltered Hg{sub T} increased from 1.8 to 19 ng L{sup {minus}1} (n = 3). Filtered Hg{sub T} levels were highest at wetland/forest sites, followed by forest, cropland/forest, and crop-land/pasture sites. Unfiltered methylmercury (MeHg) showed similar patterns, with highest levels observed at wetland/forest sites, followed by forest sites and cropland/forest sites. With these data, the State of Wisconsin can more effectively and accurately regulate and monitor Hg levels.
- OSTI ID:
- 49615
- Report Number(s):
- CONF-9410273--
- Country of Publication:
- United States
- Language:
- English
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