Huge water main break early this morning closed Argonne Avenue.

Chemical concentrations in Baltimore city drinking water exceed health guidelines — and in the case of three substances, legal limits, according to a state-by-state survey of publicly-available data, published yesterday in The New York Times.

We wanted to ask Baltimore Department of Public Works spokesperson Kurt Kocher to respond to this news, but unfortunately he was tied up dealing with the whopping water main break that occurred in the 1600 block of Argonnne Avenue last night.

While Kocher and city crews address the latest breakdown in Baltimore’s aging infrastructure (it was a 24-inch, 70-year old pipe that burst, causing water to gush through the street, and a gas line to go out too) we’ll tell you what unhealthy chemicals appear to be in that water. (And see cool video of the flood on Argonnne Ave,))

The Times’ s front page story, part of a series on water pollution in the U.S., was based on data compiled by the Washington-based Environmental Working Group. EWG used data provided by the Maryland Department of the Environment, reflecting testing conducted from 2004 to 2008.

The three contaminants found in illegally high concentrations in Baltimore City tapwater were: total haloacetic acids (HAAs), total trihalomethanes (TTHMs) and nitrite.

(The first two are “disinfection byproducts,” according to EWG.  Nitrite is more commonly known. As the EWG chart explains, it enters the water from fertilizer runoff and leaching septic tanks.)

In having three of these “exceedences,” Baltimore was much worse than the national average, which is .5, according to the chart.

Similarly, with the 14 substances that exceeded health limits, the city was again far worse than other U.S. public water systems, which on average exceeded health limits with 4 chemicals. Among the most consistently-detected chemicals found over the four-year-period were: chloroform, bromodichloromethane, dibromochloromethane, dichloroacetic acid and trichloroacetic acid.

The other substances that exceeded the health guidelines according to the EWG survey are: bromoform, Di (2ethylexyl)phthalate, lead (total), copper, Alpha particle activity (excluding radon and uranium) and radium 226.