Could you address the effect of the overall pollution that enters the lake via the Maumee River, as well as the effect of lake ships and what they use to clean decks and boats on the phosphorus?
There are numerous pollutants from many sources that enter the Maumee River and have an impact on the Lake. However, the contaminants that are of primary concern for stimulating algae blooms and impacting water quality in Lake Erie are sediment and nutrients namely phosphorus and nitrogen, The Maumee River is the largest single source of sediment and nutrients to Lake Erie. The best measurements that we have for the Maumee River loadings come from the gauging station at Waterville. Average annual loadings reported by the Heidelberg University in metric tons are as follows: Suspended solids=954,600, total phosphorus=2338, dissolved phosphorus=554 and Nitrate Nitrogen= 31,800. While a significant decline in suspended sediment and total phosphorus has occurred since the 1970s, an increase in dissolved phosphorus has been trending upward since about 1995 and this increase coincides with the increase in algae blooms in the Lake Erie.
Ohio EPA reports that all commercial ships of any significant size are covered by the Vessel General Permit (VGP). The VGP covers a wide range of discharges from vessels, including cleaning. This permit requires the use of phosphate-free cleaners as part of the Best Management Practices. If deck washdowns or above water line hull cleaning will result in a discharge, they must be conducted with non-toxic and phosphate free cleaners and detergents. Furthermore, cleaners and detergents should not be caustic or only minimally caustic and should be biodegradable. The VGP also cover several additional vessel discharge issues and a copy can be viewed at: http://cfpub.epa.g ome.cfm?program_id=350ov/npdes/h.
Ed Hammett, Ohio Lake Erie Commission