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BIOAVAILABILITY OF MERCURY IN SEDIMENTS FROM A FLOOD CONTROL RESERVOIR TO HYALELLA AZTECA
Citation:
Huggett, D. B., D. B. Block, J. C. Allgood, AND W H. Benson. BIOAVAILABILITY OF MERCURY IN SEDIMENTS FROM A FLOOD CONTROL RESERVOIR TO HYALELLA AZTECA. SETAC 20th Annual Meeting, Philadelphia, PA, November 14-18, 1999.
Description:
In the last three years, mercury contamination in North Mississippi flood control reservoirs has become a growing concern. Previous data indicate that three flood control reservoirs have similar total mercury sediment concentrations and that fish collected from one reservoir contain mercury concentrations in their edible tissues that are at or above the 1.0 mg Hg/kg FDA standard. However, it is unknown as to the source of mercury and if the mercury in the sediments of these flood control reservoirs is bioavailable.In an effort to investigate bioavailability of mercury, surficial sediments were collected from Enid Lake, which currently has a fish consumption advisory. Total mercury concentrations in these sediments ranged from 10 to 48 ug Hg/kg, wet weight. Survival of adult Hyalella azteca after a 21 d exposure to Enid Lake sediments was >=83%. Mercury body burdens for H. azteca ranged from 0.093 to 0.192 mg/kg; however, these values were at or below background levels. While mercury in Enid Lake sediments does not appear to be bioavailable, other biological (e.g. growth) and chemical (e.g. acid volatile sulfides) parameters may be more sensitive indicators of mercury bioavailability. In addition, seasonal differences in bioavailability resulting from flood control practices will be discussed.