In seston, mean concentrations ranged from 50 to 241 ng/g dry weight for total Hg and from 1.2 to 16.2 ng/g dry weight for MeHg, which accounted for 5.3% ± 2.1% of the total Hg in seston (Table 3). Seston from the Beaver Pond at Snow Creek had the highest concentration of MeHg.