Although many people are happy to enjoy the St. Louis River Estuary at arm’s length, many others choose to immerse themselves in it, or at least enjoy a variety of water recreation activities. For people who intentionally or unintentionally get wet, water quality must be good enough that there is only a small risk of getting sick if they (or their pets) swallow any. They certainly should not have to worry about medical problems from simply getting wet. Yet, there have been sites along the river (Hog Island, Newton Creek, Crawford Creek in Wisconsin, and the US Steel and Interlake Superfund sites in Minnesota) where industrial contamination by chemicals in the water column was hazardous enough to cause these areas to be posted with “No Swimming” signs. Most of these problems have now been fixed and the sites are in various stages of restoration, although “No Swimming or Body Contact” signs remain at the US Steel Superfund site in Morgan Park, which is not yet remediated.
Disease-causing organisms are now the major cause for human health concerns in the estuary and AOC. Historically high levels of fecal coliform bacteria, an indicator of feces from warm blooded animals, were dramatically reduced after 1978 when the Western Lake Superior Sanitary District (WLSSD) was formed to collect and treat most of the industrial organic matter and domestic wastewater load from municipalities and industries in the region. Since that time, Superior and other municipalities discharging into the Wisconsin side of the estuary have also greatly upgraded their treatment facilities. Nevertheless, chronic risks to public health, as indicated by wastewater bacterial indicators, have continued to cause areas of the estuary to be posted with swimming advisories on occasion, presumably due to sewer overflows caused by extreme rainfall events, sewage spills, discharge from boats, and failing septic systems.
Since the early 2000s, considerable progress has been made by Superior, WI and Duluth, MN to upgrade sanitary sewer infrastructure and provide temporary storage designed to reduce discharges resulting from equipment failure and overflows caused by rainfall-associated inflow and infiltration. These projects are expected to be completed in 2016 (source: MPCA BUI 7 Blueprint. Similarly both states continue to upgrade rules to improve on-site wastewater treatment systems, although this is a long-term process.
In 2003 both Wisconsin and Minnesota initiated summer bacteria monitoring and advisory programs at public beaches. When indicator bacteria levels exceed state and federal criteria the public is warned against swimming via advisory signs, website warnings, and through various media outlets.
To date, advisories have been rare for the Lake Superior beaches, and infrequent for most, but not all, of the estuary “beaches” (most are actually small boat landing and docking sites).
More than 10 years of research by University of Minnesota scientists using state-of-the-art genetic fingerprinting techniques has shown that exceedances at some of the sites with chronic advisories appear to be a result of the indicator bacteria E.coli coming mostly from bird feces from the large flocks of gulls and geese that inhabit the estuary (details here). Further, measurements of pathogenic genes associated with E. coli and several other waterborne disease-causing bacteria have indicated extremely low risk and were not correlated with beach advisories from the routine monitoring. Nevertheless, although human pathogens may not usually be much of a risk at these “chronic” sites, it is unclear to what extent bird or other wildlife diseases associated with these high indicator values might pose a significant risk to humans. As of 2014, four sites in the SLR AOC that have been designated as “impaired” by Minnesota and Wisconsin have been targeted for more in-depth study using DNA fingerprinting technologies to better identify E.coli sources (Barker’s Island Inner Beach and Wisconsin Point Beach #2 in WI, and the Clyde Avenue and Leif Erickson Park sites in MN.
Monitored Beaches in the St. Louis River Area of Concern. Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013. Click to zoom.
Impaired St, Louis River AOC beaches targeted for microbial source tracking to determine if pathogens are of human origin (i.e. controllable). Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013. Click to zoom.
Throughout the Great Lakes, stormwater runoff has been shown to increase water-borne disease risks as indicated by E.coli monitoring. A consistent public education message is to:
…. minimize, or avoid water contact in general, in streams and lake coastal areas following rainstorms, since pathogens washed in from the watershed typically increase.
Large investments in sewage infrastructure and temporary storage are only recently bringing this problem under control during big rainstorms and high spring snowmelt runoff years.
Attempts have been made to accurately predict E. coli exceedances in real-time, that is – when people are planning to leave for the beach. These predictions, based on rain, wind, and water clarity (estimated using sensors that measure turbidity), have been useful for Ohio beaches in southern Lake Ontario (see Ohio Nowcast) and are being developed and tested for other Lake Michigan and Lake Huron metropolitan area beaches Lake Michigan and Lake Huron metropolitan area beaches . Thus far, the ten years of data for the lower St. Louis River Estuary have not been very promising in terms of generating such predictive “forecasts,” because the data are highly variable. Perhaps the two biggest limitations to improving the accuracy of the warning programs include: (1) The testing requires 24-48 hours to culture bacterial colonies, which means some advisories are not posted until a day or days after the exceedance occurred; and (2) Actual illnesses due to water contact at “advisory sites” are not likely to be reported to health providers unless symptoms are severe. Health officials and scientists are working on both of these issues, and rapid DNA testing kits are likely to provide more timely advisories in the next few years. Epidemiological studies that link illness to actual water contact at a particular beach will likely be based on Great Lakes-wide surveys, since the incidence of traceable symptoms in our region is rare.
Recreational experiences in the “pre-WLSSD“ days were also marred in many areas by taste and odor problems, industrial foam, oil slicks and sheens, tar balls, grain or grain dust, taconite pellets and residue, coal, etc. These issues seem to have largely disappeared as a result of the many remediation projects carried out in the past two decades. Noxious scums of algae, such as the blooms of tiny blue-green algae that are suspended in the water on occasion in Lake Erie or the massive piles of attached filamentous algae that have plagued the shoreline of western Lake Michigan for the past decade or more, have not been observed in the estuary. Since nutrient levels in the St. Louis River Estuary are sometimes high enough during the ice-free season to support large algal blooms, algal growth is likely limited by other factors. These include low levels of sunlight penetration caused by naturally dark, root beer-colored water and occasional muddiness caused by high suspended sediment loads. This “potential” for excess algal growth in the SLRE (as well its effects on Lake Superior) is the reason that new research efforts are underway to learn more about how changes in nitrogen, phosphorus, and light availability affect algal growth in the estuary (see the research here and here ).
Water quality also has indirect, but critical importance to the many types of water-based recreation linked to fish and wildlife, such as hunting, fishing, and bird-watching. High quality water is essential to maintain the healthy aquatic and wetland habitats required by fish and wildlife populations in the estuary. The good news is that tremendous progress has been made in the past 30 years to correct the worst of the problems, and funding since 2009 from the Great Lakes Restoration Initiative has created strong local and regional partnerships to fully restore the ecological condition of the estuary and all of its beneficial uses.