Tuesday, November 14, 2006

3170 No toxic soup after Katrina

One of the myths the media used to terrorize us after the Katrina disaster was the "toxic soup" story. The Mississippi River and Lake Pontchartrain were already some of the dirtiest water sources in the nation even before the storm. However, within a few weeks they had recovered remarkably--much faster than anyone expected. The water was unsanitary, but not toxic. The most recent issue of Environmental Science and Technology November 15, 2006, reports that the U.S. Geological Survey (USGS) testing shows very little difference in the pollution level of the lake a year later than before the storm.

"Compared to lake sediments all over the country, Lake Pontchartrain sediments are similar,” says Peter Van Metre of USGS, who is the lead author of the ES&T research. “There’s a lot of urban contamination, and Lake Pontchartrain is typical of that.” Still, Van Metre and his colleagues found that pollutants were concentrated at the mouth of the 17th Street Canal, through which much of the flood water was pumped out of the city.

The team analyzed mud from the city and sediments from canals and Lake Pontchartrain for a long list of possible urban contaminants. In some cases, particularly for fragrances, newer pesticides, and cholesterols, they used novel methods. Zinc, PCBs, and DDT, among other compounds, appeared in mud and lake-sediment samples at the mouths of several canals. High concentrations at many sites dissipated weeks after the hurricane passed. Lake Pontchartrain “is big enough and the circulation is strong enough in and out of the Gulf of Mexico” to dissipate those inputs, Van Metre says."

And speaking of water contamination--we're all contributing to the headache!

Last week contaminated acetaminophen, a common headace remedy, was in the news. Sometimes it is doing the contaminating. The National Institute of Standards and Technology (NIST) chemists investigated probable chemical reactions involving acetaminophen when the drug is subjected to typical wastewater processing. Acetaminophen is the most widely used pain reliever in the United States, and a study of 139 streams by the U.S. Geological Survey found that it was one of the most frequently detected man-made chemicals. The drug readily reacts in chlorine disinfection to form at least 11 new products, at least two of which are known to be toxic. From NIST Tech Beat. Abstract.

No comments: