Paper No. 29-9
Presentation Time: 8:00 AM-12:00 PM
MERCURY INCREASES IN LAKE TANGANYIKA SINCE ~1880
A series of sediment cores were collected in Lake Tanganyika, Africa, and were analyzed for mercury concentrations. A general trend is observed in each of the three cores that were studied. A decrease in mercury levels was observed from the 1600’s (appx. 20 ng/g) until concentrations reached a minimum during the mid-1800’s (appx. 10 ng/g). This decrease is likely driven, at least in part, by dilution with carbonate phases, which increase over this time period. The mid-1800’s marks a change from the decreasing mercury levels to an increase over the following century. The most recent results (circa 2006) show a rise in concentration to over 70 ng/g. The rise in mercury concentrations coincides with the beginning of the Industrial Revolution, which began in the mid to late 18th century. Close correlations between δ13C values in carbonates and Hg concentrations suggest that the mercury levels in this system are likely dominated by fossil fuel combustion rather than other anthropogenic impacts.