In the four centuries since Henry Hudson discovered it, his namesake river has endured an onslaught of varied pollutants. In the nearly four decades since the federal Clean Water Act became law, the health of the Hudson River has taken a significant turn for the better, but significant challenges remain.

Sewage and stormwater runoff are the river's biggest threats these days."This summer's dredging of PCBs from the Hudson River (near Fort Edwards) reflects a fading echo of the worst abuses from its industrial past...It has been decades since that kind of unfettered pollution spilled from factory pipes," The Times Union reported.

At Troy, stoneflies reappeared in 1997, showing the water was clean enough to support them. By 2002, there were six water fly species there, compared with just one species in the early 1970s. The increasing presence of these clean-water insects, a food source for fish, demonstrate improving water quaity in this part of the Hudson River, Yancey Roy, a state Department of Environmental Conservation spokesman told the newspaper.

However, downriver, in Dutchess County and points south, progress is not as obvious, according to Roy and to John Cronin, head of the Beacon Institute for Rivers and Estuaries.

The greatest threat to the Hudson River today is non-point-source pollution, as opposed to the single-source pollution of the past from easily identifiable factory discharge pipes. An ever-growing number of people live near the river and rely on aging sewer systems that spill untreated sewage into the river when it rains.  This storm overflow scoops antifreeze, oil, pesticides and fertilizers into its waste stream.

Whatever solutions are required likely will be expensive.  However, the city of Syracuse and surrounding Onandaga County recently asked a federal court's permission to clean up polluted runoff into Onandaga Lake using beefed-up natural systems, like green roofs and large-scale tree plantings to act as sponges and filters. This could prove to be an innovative money saver.