for National Geographic News
Yesterday engineers in New Orleans got pumps up and running, sending tens of thousands of gallons of floodwater gushing out of the waterlogged city and back into Lake Pontchartrain.
The good news was tempered, however, as public health officials and environmental experts warned that the inky black water is a highly contaminated cocktail of petrochemicals and sewage.
EPA administrator Stephen L. Johnson announced at a press conference this afternoon that preliminary testing of floodwaters in New Orleans showed high amounts of bacteria associated with raw sewage, as well as high amounts of lead.
Johnson said every sample tested revealed levels of E. coli bacteria that were ten times the federal safety limit.
Mike McDaniel, Louisiana Secretary of Environmental Quality, had previously told reporters, "It's almost unimaginable the things we are going to have to deal with."
In New Orleans pumping began after 500 engineers, contractors, and laborers with the Army Corps of Engineers patched two levees that Katrina's waters breached.
By midday yesterday, 10 of 40 pumping stations in the greater New Orleans area were working, said Walter Baumy, chief of engineering for the U.S. Army Corps of Engineers.
Floodwater in the city became contaminated as it cascaded through streets and into more than 160,000 homes and businesses. The torrent split open containers of household chemicals, overturned automobiles and cracked their gas tanks, and disturbed underground gas and oil tanks.
Adding to the toxic brew is runoff from leaking sewer and gas pipes, which sustained damage when Katrina toppled trees; roots ripped soil and pipes from below ground like giant pitchforks.
Human corpses and dead pets and other animals have also not been cleared from city floodwater, further raising the risk of bacterial contamination.
Reuters quoted New Orleans mayor Ray Nagin saying, "It is a health risk. There are toxins in the water." He estimated that about 60 percent of his city remains underwater, a drop from 80 percent last week.
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