Diesel and fuel oils are a new problem for New Orleans

A new health risk emerged Friday from the sediment of New Orleans as test results showed that diesel and fuel oils, which can take years to break down, comprise as much as a tenth of the weight of some sediment samples.

The test results came from 18 samples drawn Sept. 10 from across the New Orleans area, where there have been five oil spills associated with the flood since Hurricane Katrina struck Aug. 29. Earlier tests turned up dangerous amounts of sewage-related bacteria and lead in floodwaters and more than 100 chemical pollutants.

The government's Environmental Protection Agency said it also found E. coli bacteria in the sediment, residue from water, soil from backyards and road and construction debris, as well as slightly elevated arsenic and lead levels. It didn't say what the levels of E. coli bacteria were, and there's no health standard for how much E. coli can be in soil or sediment.

Fuel oils such as kerosene, jet fuel, range oil and home heating oil irritate the skin and, if breathed, cause nausea, headaches, increased blood pressure, lightheadedness, appetite loss, poor coordination and difficulty concentrating. Breathing diesel fuel vapors for long periods can cause kidney damage and lower the blood's ability to clot.

William Farland, EPA's acting science adviser, said he was "not seeing anything in the sediment that suggests a big public health risk, as long as people are careful to remove the sediment, keep it from getting on their bare skin and clean it off if they do."

New Orleans Mayor C. Ray Nagin said this week he expects some of the city's neighborhoods to reopen and up to 180,000 people to move back over the next two weeks as electricity and water are restored .

Scientists worry, however, that as the sediment dries, the pollutants in it can evaporate and become gases in the air that people could breathe in. Some chemicals found in fuel oils can easily evaporate into the air, while others more easily dissolve in water. The agencies plan to collect air samples to keep tabs on that, AP reports.