R2 PM Evaluating Short- and Long- Term Effectiveness In Sediment Remediation
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 2

(KUB-1117-845842) Monitored Natural Attenuation of the Deer Lake reservoir Area of Concern.

Kubitz, J¹, ¹ ELM Consulting, LLC, Barrington, Illinois, USA

ABSTRACT- The Monitored Natural Attenuation (MNA) remedy for the Deer Lake reservoir Area of Concern (AOC) has been effective. Maintenance of a constant water level was the selected remedy in the 1987 Remedial Action Plan. The effectiveness of the RAP remedy has been evaluated by monitoring the uptake of methyl mercury by northern pike. Methylmercury uptake by Deer Lake pike has declined through time; the process has occurred in three steps. The 1979 to 1985 year classes of pike accumulated an average of 7 mg of methylmercury by age 3. Deer Lake pike from the 1986 to 1992 year classes took 6 years, on average, to accumulate 7 mg of methylmercury. Pike from the 1992 to 2002 year classes in Deer Lake require an average of 11 years to accumulate 7 mg or methylmercury. At present, Deer Lake pike accumulate methylmercury at the same rate as pike in Greenwood Reservoir, which is a local reference lake (Kruskal-Wallis Analysis of Variance on Ranks; Dunns Method for Median Comparisons at =0.05.

Key words: methylmercury, fish, sediment, remedy