Pittsburgh's three rivers remain heavily tainted with metals, harmful chemical compounds, pathogens, and silt, according to a report released last week by the Pennsylvania Department of Environmental Protection (DEP).
Some of the most common sources of pollution are abandoned mines, as well as the "urban runoff" that results from a lack of vegetation along the riverbanks. Both of these are known to suppress aquatic life. The Allegheny, Monongahela, and Ohio Rivers are all experiencing problems from mine drainage and runoff.
All three rivers earned several counts of the DEP's most serious level of water quality action, "Category 5." In these cases, pollution is severe enough to harm wildlife or prevent recreation, drinking, or fish consumption.
The Ohio River is struggling with the presence of dioxins, a class of chemical compounds that is thought to increase cancer risk and possibly harm human development. Dioxins accumulate in animal tissue over the course of a lifetime; in 10- and 40-mile spans of the Ohio River, the fish have enough dioxins in their tissue for the DEP to warn against eating them. In addition, unnamed "pathogens" from an unknown source have prompted the DEP to discourage water recreation on a 50-mile stretch of the Ohio. The length of the Pennsylvania segment of the Ohio River is just about 50 miles.
The Mon and the Allegheny
In the Monongahela, mine drainage combines with industrial pollution in many areas. In Pennsylvania, that creates an 82-mile stretch of water that's unsafe to drink. The Mon itself is 130 miles long total, including a sizeable part in West Virginia, where the river has its source.
A five-mile span of the Allegheny River near Pittsburgh is not drinkable because of pathogens, which are generally bacteria or fungus. Further up the river, in the northern counties of Pennsylvania, the Allegheny suffers from high levels of mercury and PCBs, which both cause human health problems. For more than a hundred miles of the Upper and Middle Allegheny, the fish should not be eaten.
DEP spokesman Kevin Sunday said it's hard to pinpoint from where some pollutants, such as mercury and PCB, are coming. He said the DEP has to investigate for possible sources and, in the meantime, put a ban on eating fish in those cases.
"In other cases, where we are near population centers, where there's a lot of wastewater treatment plants and we see a lot of water quality issues associated with the discharge of sewage water, well then we know that we can focus in on those water quality issues and cut down on the discharge of the sewage treatment plants in the area," said Sunday.
He said the DEP must use "legal and responsible" methods for cutting down on pollution from known sources, which he said requires cooperation with the owners and can take years.
The water quality report from the DEP comes out every three years as required by the U.S. Environmental Protection Agency.