Atmospheric Mercury Deposition near Mobile Bay
The Alabama Department of Environmental Management (ADEM) and the Mobile Bay National Estuary Program (MBNEP) have begun the states first program to measure pollution deposited through rainwater in Mobile and Baldwin counties. Samples taken from the monitoring stations will be used to determine how much mercury and nutrients are deposited in local watersheds through rainfall. The data gathered will be part of the National Atmospheric Deposition Program, which consists of about 250 monitoring sites from Alaska and the continental United States to Puerto Rico and the Virgin Islands. Rainwater will be analyzed for total mercury, sulfate, nitrate, ammonia, sodium, potassium, calcium and magnesium. Each sample will also be checked for pH (a measure of acidity/alkalinity) and specific conductance.
Research indicates that under certain water chemistry conditions, common to black-water coastal streams, mercury is prone to bioaccumulate in predatory fish species. Scientists theorize the source of the mercury may be the result of atmospheric deposition from industrial releases or even natural conditions in coastal waters. Florida and Mississippi have encountered similar situations. Several migratory fish species in the gulf and on the East Coast also show mercury accumulations. This national monitoring program will help answer questions on the source(s) of mercury.