The Lake Champlain basin is under attack from increasing amounts of chemical compounds, including PCBs, phosphorus, and mercury.  Mercury is the hardest compound to measure and most expensive, this is why a computer model has to be developed to show that there is a danger of too much mercury in the Lake Champlain basin.  Using an interactive software STELLA v6.0 this project will attempt to construct a model that will explain the levels of mercury in the lake.

 

There are numerous reasons that something has to be done about the mercury present in the lake. Once mercury enters the water, it chemically changes to its most deadly form methyl mercury.  When this methyl mercury is present in the lake it is taken in by small aquatic organisms.  Fish then consumes these organisms.  The elevated levels of mercury in fish if consumed by humans could be hazardous or even fatal.  The mercury effect in fish also affects birds in the area as well.

 

The objective of this project is to develop a mass balance model based on the thermodynamic law, conservation of mass.  In order to employ this basic principle all of the inputs into a reservoir, Lake Champlain, will have to be estimated or measured.  As well as the inputs the amount of Hg leaving the lake has to be measured or estimated as well.  Once the data has been obtained or estimated the concentration from each source as a function of time will be integrated into a computer model of the accumulation.
 

The mass fluxes of mercury in the lake will be determined based on atmospheric and water sampling.  The atmospheric deposition samples have been collected from Underhill, Vermont.  The major tributary flows into the lake will be determined using USGS gage for water flux and water samples are collected for Hg analysis.  In addition, mercury analysis was done on lake water, sediment, and biota samples. For the inputs and losses that cannot be determined such as other rivers or runoff the values will be estimated.  As this project progresses there is hope that the additional sampling will commence in the places where no data has been taken, this will help to refine the model and gain a better understanding of the current conditions and future environment of the lake.  This mass balance modeling will also help determine what has to be done to remediate the problems that have developed.