Lake Michigan Mass Balance

There have been a few large-scale field studies of PCBs in the food webs of the lakes. These include two EPA mass balance studies, the Green Bay Mass Balance Study and the Lake Michigan Mass Balance Study. The field data collected for these studies was used to calibrate the complex contaminant models, which were developed as the primary goal of the studies. The ultimate objective of these mass balance studies was to predict concentrations of PBTs in top predator fish from only knowing the external loadings of the PBTs. Thus the models linked food web models to fate and transport, hydro-logic, and nutrient models. To calibrate the food web models, an extensive collection of all major trophic levels over both space and time was done and analyzed for PCBs and other selected analytes. 

Fig. 14 Lipid-normalized PCB concentrations in the Lake Michigan food web, showing 95th, 90th, 75th, 50th, 25th, 10th, and 5th percentiles (data from the Lake Michigan Mass Balance study)...

The LMMB study included the collection of over 25 000 air, water, sediment, and biota samples at more than 200 locations in and around the lake. All samples were analyzed for 110 individual PCB congeners [241], The Lake Michigan Mass Balance program reported a preliminary mass budget of PCBs (Fig. 15). 

McCarty HB, Schofield J, Miller K, Brent RN, Van Hoof P, Eadie B (2004) Results of the Lake Michigan mass balance study polychlorinated biphenyls and trans-nonachlor data report. US EPA... 

US EPA (2005) Lake Michigan Mass Balance Study loadings report... 

USEPA (2005) The Lake Michigan mass balance project, http //www.epa.gov/glnpo/ lmmb/substs.html. Cited 15 June 2005... 

These chapters provide examples of the types of approaches that are needed to better understand contaminant fate and transport. Some examples of aquatic models currently in use include the EPA-funded Green Bay and Lake Michigan Mass Balance Studies (36), and Chesapeake Bay Water Quality Model (37,38), Models have also been developed for atmospheric transport of pollutants including the Regional Lagrangian Model of Air Pollution (RELMAP)and the Regional Acid Deposition Model (RADM) (39,40)... 

USEPA (1997) Lake Michigan mass budget/mass balance work plan. EPA-905-R-97-018, US Environmental Protection Agency and Great Lakes National Program Office... 

Mass Balance for PCBs in the Great Lakes Lake Michigan... 

Richardson, W.L., Smith, V.E., Wethington, R. (1983) Dynamic mass balance of PCB and suspended solids in Saginaw Bay- a case study. In Physical Behavior of PCBs in the Great Lakes. D. Mackay, S. Patterson, S.J. Eisenreich, Eds., Chapter 18, pp. 329-366. Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan. 

Bierman, V., Swain, W. (1982) Mass balance modeling of DDT dynamics in Lakes Michigan and Superior. Environ. Sci. Technol. 16, 572-579. 

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