CHICAGO, Sep 12 (Reuters) A panting border collie patrols a steamy Chicago beach, chasing away sea gulls before they can foul the sand.
A sign asks beach goers to toss their trash in a bin and change their children's dirty diapers.
Chicagoans are among the millions who flock each summer to hundreds of beaches that line the shores of the five Great Lakes, the vast inland seas that are collectively the world's second-largest body of fresh water and provide drinking water for 40 million Americans and Canadians.
The five interconnected Great Lakes have been abused by polluters, invaded by unwanted species and are overdue for a cleanup, environmentalists and many politicians say.
''A lot of advocates feel the Great Lakes have long been neglected. Compare them to the (Florida) Everglades, which are that region's iconic landmark and where there's a multibillion-dollar federally funded restoration program.
That's what we need here,'' said Max Muller of the group Environment Illinois.
The price tag for restoring the Great Lakes was recently estimated at 26 billion dollars by a group of economists who projected the economic benefits of a cleanup.
Completing the immense task -- rebuilding antiquated sewer systems, restoring decimated wetlands, blocking invasive species, and cleaning up contaminated lake sediments and polluted tributaries -- would lift residential property values that are within sight of the lakes by 10 per cent, their report concluded. The 50 billion dollars real estate gain would alone justify the investment that the researchers said could revitalize the surrounding region known as the Rust Belt.
Coveted lakeshore homes can fetch prices rivaling those on US ocean coastlines, though the Great Lakes' natural beauty featuring towering sand dunes, rocky fjords, and dense forests is frequently interrupted by urban wasteland and factories.
Restoration of the lakes would also bring a healthier fishery, fewer beach closings, and other benefits, the report sponsored by the Brookings Institution said.
''To the extent you're going to make the Great Lakes a more attractive place for people to live and work, you're going to reduce (out)migration, and if anything you're going to be able to attract people from other locations and reduce congestion on the coasts and other parts of the country,'' said Brookings' economist Robert Litan.
Protectors of the lakes toted up a recent victory when British oil giant BP agreed to scuttle its permit to dump more ammonia and other pollutants into Lake Michigan from a planned Indiana refinery modernization.
The company backed down last month in the face of outraged politicians, feverish petition drives and boycott threats. But BP may abandon the project altogether, along with the promise of jobs and gasoline supplies in a region in need of both.
VIRUS ALERT Meanwhile, on dozens of hot days over the summer, disappointed beach goers in Chicago and elsewhere have been met by swimming bans.
A host of viruses that can sicken swimmers, dangerous toxins such as mercury and asbestos, and other threats lurk in or beside the lakes, scientists say. Episodes of people sickened by contaminated drinking water may go unreported.
At beaches in larger communities, swimming areas are routinely tested for the presence of E-coli, a bacteria that is a marker for other pathogens. By midsummer, Chicago had ordered 34 swim bans.
The sources of the offending pollution are numerous, but scientists working on the issue largely blame runoff after rainstorms from overloaded sewer and septic systems, from fouled urban streets, and from farm fields spread with liquefied manure.
In recent years, the Great Lakes waters sometimes appeared clearer, if not cleaner, to the naked eye, which scientists say is actually a bad sign. Due to efficient lake water filtering by the invasive zebra and quagga mussels, more sunlight reaches deeper lake depths and, combined with nutrients from runoff, promote algae growth. The plant detritus piles up along shorelines and harbors viruses from runoff, they say.
Also implicated in the swimming bans is feces from an influx of sea gulls along Great Lakes beaches, which Chicago has tried to shoo away with trained dogs and solar-powered trash compactors to collect the refuse that draws the birds.
Chicago officials have been especially vocal about getting residents to properly dispose of diapers and household chemicals, as well as offering advice on installing rain barrels, rain gardens or green roofs to absorb storm water.
Over the years, huge sums have been spent to dredge polluted lake sediments and to dig networks of tunnels and reservoirs to divert storm water contaminated with sewage that previously was released into the lakes.
But hundreds of lakefront communities do not have adequate sewage systems that will pose an worsening problem in light of heavier rainfall predicted by some climatologists.
REUTERS JT KP0848