But the LSU researchers caution that the same floodwaters that were pumped back into Lake Pontchartrain contain high levels of some toxic metals, especially copper and zinc, and could pose a long-term danger to the area's aquatic life, which are more sensitive to the metals than humans. Their findings will appear in the Oct. 11 online issue of the American Chemical Society?s journal Environmental Science & Technology.
"What we had in New Orleans was basically a year's worth of storm water flowing through the city in only a few days," says study leader John Pardue, Ph.D., an environmental engineer and director of the Louisiana Water Resources Research Institute at LSU in Baton Rouge. "We still don't think the floodwaters were safe, but it could have been a lot worse. It was not the chemical catastrophe some had expected."
Some experts had predicted that the floodwaters from Katrina could potentially destroy chemical plants and refineries in the area, releasing a deadly brew containing toxic levels of benzene, hydrochloric acid and chlorine. Instead, high levels of bacteria and viruses were the biggest human threat, not exposure to chemicals, Pardue and his associates say.
The researchers obtained 38 floodwater samples from widespread sections of New Orleans, primarily in the area of the city known as the "East Bank," where the main human contact with the floodwaters occurred. The samples, which included both surface waters and bottom samples, were taken within five to nine days af
Source:American Chemical Society