The researchers found high levels of bacteria, most likely from fecal contamination resulting from sewage. Levels were within the range of typical storm-water runoff in the city, the scientists say. They also detected high levels of lead, arsenic and chromium and noted that levels of these toxic metals were also similar to those typically found in the area's stormwater. In general, these particular findings were similar to those obtained by the Environmental Protection Agency in their initial assessment of the floodwaters, the researchers say.
Gasoline was also a significant component of the floodwaters, as measured by elevated levels of three of its components: benzene, toluene and ethylbenzene. These compounds were somewhat elevated in comparison to typical stormwater runoff, the researchers say. The chemicals most likely came from cars and storage tanks submerged in the floodwaters, they add.
Compounds found in common household chemicals were also detected in the floodwaters, Pardue says. The waters contained chemical compounds from aerosol paints, insecticides, caulking compounds, rubber adhesives and other common substances, they say, but at levels that typically do not create concern for human health.
If the floodwaters had occurred in another location near more industrial sites in the city and if the wind damage or water surge had been more severe, then the resultant floodwaters could have been a more serious toxic threat, Pardue says. "Instead, the city filled slowly, like a bathtub, and the water velocities and forces on the buildings, including chemical storage facilities, were relatively benign," he says. The large volume of floodwater also diluted the potency of many of the chemicals, he a
Source:American Chemical Society