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Experts Size Up Contaminants Water Full of Bacteria,No 'Toxic Soup'

Posted on: Monday, 19 September 2005, 18:00 CDT

An LSU expert working with the U.S. Environmental Protection Agency's science advisory board on how to sample sediments said the agency needs to be sampling inside as well as outside the flooded homes in the New Orleans area.

Hurricane Katrina overtopped some levees and broke floodwalls. All of St. Bernard Parish flooded along with a large portion of Plaquemines, St. Tammany and Jefferson parishes. Eighty percent of Orleans Parish was inundated.

As floodwater recedes, residents will be faced with a layer of muck. Exactly what is in that sediment may determine to what substances people cleaning up are being exposed.

The EPA, in conjunction with the Louisiana Department of Environmental Quality, has sampled only outside the homes.

LSU chemistry professor Louis Thibodeaux said sediment-laden floodwater "comes through the front door and it settles out in the house because" the water is still, and really fine particles fall out of the water.

"That's where the contamination is going to be," he said.

But, he said, the EPA seems to be reluctant to go into the houses. "Inside, you are going to get it all over you" as people clean up, he said.

"There was a lot said about pathogens - that was the critical thing," Thibodeaux said, noting the floodwater and sediments left behind have high levels of fecal coliform bacteria, which could cause diarrhea, nausea and other ailments.

State Health and Hospitals Secretary Fred Cerise has advised residents of St. Bernard, who were being allowed back into that parish Saturday, to use caution, to drink bottled water only, to wear gloves and other protective equipment, and to cover any open wounds.

He advised children and elderly people with conditions like asthma, allergies and compromised immune systems not to return to their homes.

Thibodeaux, who headed LSU's Hazardous Waste Research Center for several years, said some advisory board members also feel EPA needs to get more information on pathogens beyond just E. coli and total coliform.

"The critical issue here is not so much the chemicals, but the pathogens," he said. Once pathogens in dried sediment become wet again, people could be re-exposed. Also, there is a concern about inhaling dust from dried sediment.

"The chemicals are the second order of magnitude," he said.

Studying long-term effects

William Golz has spent the past 10 years writing models to describe the long-term behavior of contaminants after they enter wetland environments.

"Although short-term concentrations of contaminants in the floodwater appear small, natural processes will ultimately concentrate these contaminants in sediments. ... This environmental magnification of contaminants makes longer-term impacts difficult to predict, and it is long-term impacts that have given us such things as declining reproductive success for Louisiana's brown pelicans and the elevated mercury concentrations now found in fish caught in many Louisiana water bodies," said Golz, who did his research at LSU.

"It is premature to state that there won't be any impact on human health, when the probabilities are that we will see measurable long- term consequences from the contaminants now being discharged into Lake Pontchartrain," said Golz, who is now doing water modeling for DEQ and was speaking for himself.

Meanwhile, environmental groups also are looking at the data and trying decide what it means.

Darryl Malek-Wiley of the Sierra Club, himself an evacuee from New Orleans, said EPA and DEQ's sampling is limited. "They are taking a snapshot here and a snapshot there" and the locations of the sediment samples taken were not disclosed. Even DEQ officials are unsure of where sediment samples were being taken.

Malek-Wiley said he had not seen anything overly alarming in the test results, but noted that EPA and DEQ have not released any sampling data from areas that have been impacted by flooded industrial sites, such as the Murphy Oil facility in Meraux in St. Bernard Parish.

As people begin to stream back into the parishes evacuated, they will be grabbing clothes and keepsakes and possibly exposing themselves not only to pathogens but to some chemical contamination.

He also said he is concerned that the Federal Emergency Management Agency has not called in the Occupational Safety and Health Administration to look at exposures to rescue workers. A similar failure happened after the Sept. 11 terrorist attacks in New York City, he said.

Bacteria or 'toxic gumbo'?

Louisiana DEQ Secretary Mike McDaniel said he takes issue with the constant reference to the floodwater and muck left behind as being "toxic soup" or "toxic gumbo."

The main problem is bacteria rather than toxic chemicals, McDaniel said.

Lead levels in some floodwater samples were much higher than the drinking water standards, but McDaniel said he doubts anyone would drink the floodwater.

Toxicologists Dana Shepherd and Tom Harris are leading the DEQ "data team" looking at the samples from the flooded areas.

"Generally, we are seeing nothing being detected. Just because there is one exceedance," or reading above water standards, "doesn't mean we're sending up the red flag," Shepherd said.

Generally, higher readings mean more investigation is needed, especially when the water recedes, she said.

"What we have seen so far is pretty encouraging," Harris said.

Sediment samples often register 12 parts per million of arsenic - but that's basically a "background" or natural level in soils in south Louisiana, they said. In one instance, a sample found 240 parts per million, and that probably will require a closer look in that area, Shepherd said.

Hexavalent chromium, considered a human carcinogen, has appeared in some samples, with the largest reading at 553 parts per million. EPA's action standard is 210 parts per million in a residential yard. The occupational exposure limit is 3,100 parts per million.

"I would hardly consider 536 (ppm) a dangerous level," Harris said. They don't know where the sample was taken - in a residential or a commercial area - and Harris said the reading falls between the two.

One sediment sample also had 752 parts per million of lead. The residential standard is 400 parts per million, so the sample is about twice the action level for lead, they said, and well below the occupational standard.

Which standard for water?

When it came to floodwater, Harris and Shepherd said, DEQ decided it would be better to compare the contaminant levels to the standards applied to lakes and streams rather than the drinking water standards EPA is using.

The surface water standards consider contact with the water, some incidental ingestion and the impacts on wildlife. Those match the real concerns for floodwater, they said.

In results taken during the period of Sept. 3-10, Shepherd said, the maximum readings have often exceeded those surface water levels for the plasticizer di (2-ethylexyl) phthalate (also known as DHEP), lead, thallium and benzene.

Benzene levels topped out at 18 parts per billion, compared with a standard of 13 parts per billion. Benzene is a known carcinogen and common in gasoline. It usually evaporates but can be suspended in water.

For the DHEP, the high reading was 12 parts per billion, twice the state standard limit of 6 parts per billion. DHEP can cause nausea in the short term and been associated with reproductive problems in the long-term.

Thallium peaked at 27 parts per billion, 13 times greater than the 2 parts per billion standard. ASTDR said it does not know what the effects of consuming low-levels of thallium over a long period of time may be.

The highest lead reading was 846 parts per billion compared to a state limit of 50 parts per billion. Lead is known to be toxic to the nervous system development in children.

And while Shepherd and Harris say the solution to pollution is not necessarily dilution, the floodwater will go into a much larger lake system and be watered down.

Harris said the readings he sees are not much greater than what would be expected for water running off any urbanized landscape.

The two said they expect to see some high contaminant levels in the water and sediment around flooded industrial facilities like Murphy Oil. "We haven't seen any data that frankly approaches the toxic soup description" from the residential sections of New Orleans.

"When we get to industrial areas, we will be looking much closer" as EPA and DEQ begin to move into more industrial areas, Shepherd said.

"This is just Phase I of several phases" of checking the soil and water in the New Orleans area, Harris said.

ON THE INTERNET

EPA Hurricane Katrina Response:http://www.epa.gov/katrina/La. Department of Environmental Quality: http://www.deq.la.gov/

Source: Advocate; Baton Rouge, La.

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