Evaluate mercury contamination in aquatic environments of Acadia National Park and Cape Cod National Seashore

Haines, Terry

'...This research project was undertaken to accomplish three objectives: 1) characterize the extent of mercury contamination in fish from ACAD and CACO, 2) determine the geological and biological factors that determine bioavailablility of mercury. and 3) detrmine historical trends in mercury deposition to ACAD...' Water and fish samples were collected in 10 lakes from ANP and others: Bubble, Eagle, Echo, Hamilton, Hodgdon, Jordon, Long (MDI), Long (IAH), L.Hadlock, Round, Seal Cove, and Somes. 1)'All species in all lakes sampled during this study exceeded the threshold for establishment of consumption advisories.' 'All of the lakes sampled at ACAD are drainage lakes, with permanent outlet streams and were chemically very similar...Therefore, it was not possible to relate fish mercury concentraion to lake physical or chemical factors within ACAD.' 2) 'Hodgdon and Seal Cove pond were chosen for food chain transfer of mercury.' Though fish assemblages were similar between the two lakes, and some similarities occured in dietary structures, there were differences revealed in dietary structres lower in the food chain. 'We conclude that the differences in biota mercury concentration result largely from differences in food chain uptake and biomagnification of mercury. It is also possible that Hodgdon Pond could recieve greater mercury inputs from the watershed, but the data are not sufficient to evaluate this possiblity.' It was also found that fish with higher mercury concentraitons were more likely to be captured by a predator thus increasing overal mercury uptake and biomagnification within the lake system. 3) 'In all cores, recent mercury accumulation exceeds pre-1900 accumulaiton by a factor of at least 3 to 5. We interpret this as mercury originating from anthropogenic sources... However, the recent accumulation of mercury in these cores is considerably higher than the measured wet deposition of mercury at the MDN collector...The difference may result at in part from dry deposition, as well as input from the watershed, neither of which is measured by the MDN wet-only collection protocol. 'The weight of evidence collected by this study demonstrates that aquatic resources at ACAD are at risk from mercury contamination, and that the contamination results from atmospheric depostion. The mercury contamination is of relatively recent origin and thus is not a result of local geologic conditions. The rate of deposition of mercury to lake and bog sediments in ACAD bagan to increase in the Early 1900's, which coincides with the development of industrial facilities and an increase in combustion of fossil fuels in the US. The difference in level of mercury contamination among different fish species is a result of differences in life history and diet, as well as differences in bioavailability of mercury among different lakes...The mercury concentraion in fish from ACAD is sufficiently high to cause adverse biological effects to the fish and probably to fish consumers as well.' For details of methodologies see Burgess (1997) /STUDY LOCATIONS:/ /MOUNT DESERT ISLAND/Bubble Pond/Eagle Lake/Echo Lake/Hamilton Pond/Hodgdon Pond/Jordan Pond/Lower Hadlock Pond/Long Pond/Round Pond/Seal Cove Pond/Somes Pond/ISLE AU HAUT/Long Pond/