FOR IMMEDIATE RELEASE
SEPTEMBER 15, 2005
Texas researchers, officials answer questions on Katrina impacts in Texas
COLLEGE STATION, TX — The Texas Sea Grant College Program has polled researchers and government agency officials from around Texas about the probable impacts on residents along the Texas coast from contaminated water being pumped out of New Orleans into Lake Pontchartrain and ultimately into the Gulf of Mexico.
Their responses are summarized below:
• Will waters from Louisiana move toward the Texas coast?
Right now the TABS (Texas Automated Buoy System) buoys are showing the nearshore currents as downcoast or westward, which means they are from Louisiana towards Texas. This is the circulation pattern during most of the year. The circulation is in the opposite direction during the summer months. The winds generally change around the first week of September to end the summer season, which pushes the currents towards Texas from the Louisiana side.
I think the most crucial point is whether the contaminated water is going into Lake Pontchartrain and not making its way into the Mississippi River. Lake Pontchartrain is not really connected to the Mississippi River. Pontchartrain comes out north and east of New Orleans, out onto the Mississippi Sound. That water will find it difficult to come around the entire Bird’s Foot Delta and make its way onto first the eastern Louisiana Shelf and then to get entrained in the shelf circulation and be taken all the way over to the west. A study a few years ago showed that there is very little communication westward from the continental shelves of the northeastern Gulf of Mexico with the continental shelves of the northwestern Gulf of Mexico because the Bird’s Foot Delta extends out into the shelf and separates the two. A lot of what is going into Lake Pontchartrain is likely to stay east of the delta.
But if there is water coming down the Mississippi River which was pumped out of New Orleans, it could make its way onto the shelf and get entrained in this circulation, which will send it to the west. Of course, I don’t know whether the chemical contaminants will remain in the water at harmful levels during that transit to the west.
— Steven DiMarco, Associate Professor, Oceanography, Texas A&M University
• Will the contamination still be at serious levels when it gets here?
I don’t have concerns about the water getting into Galveston Bay because any contaminants will be fairly well dispersed in the open Gulf waters before they reach here.
— Sammy Ray, Professor, Marine Biology, Texas A&M University at Galveston
I don’t believe there will be an impact on Texas’ coastline. The water will flush slowly into the Mississippi Bight, and the water there will mix gradually out into the Gulf of Mexico. I think the normal oceanographic processes will be almost immediately effective — any pollutants will be rapidly diluted with seawater. And the currents sending water in Texas’ direction are presently weak ones.
— Norman Guinasso, Director, Geochemical Environmental Research Group, Texas A&M University
• Is anyone in Texas testing our waters now?
There are monitoring programs in place, both by the Texas Department of State Health Service, which samples to see if a beach is safe for swimming, and by the General Land Office, whose Beachwatch program monitors for fecal contamination.
— Sammy Ray, Professor, Marine Biology, Texas A&M University at Galveston
The Beachwater program monitors Texas beaches weekly through September and biweekly through the winter months. The samples are tested for enterococcus bacteria, which is an indicator of fecal contamination. We know the levels increase after any heavy rainfall, such as that in the Galveston area this past week.
The best advice would be to check the Beachwatch web site at http://www.glo.state.tx.us/coastal/beachwatch/index.html. Any elevated readings noted need to be correlated with local rainfall and not interpreted as anything related to the effects of Katrina.
— Blake Traudt, Beachwatch Coordinator, Texas General Land Office
• How much should we worry about the spread of diseases and pollution? Can we swim in the Gulf and bays?
While it is doubtful that the contaminated waters from New Orleans will reach Texas, it is even less probable that many potentially harmful microbes would be left in the waters. First, the microbial numbers would be greatly diluted before they reached Texas; and, second, most of the microbes could not survive the time spent in the saltier offshore waters.
Primarily, the organisms in the water would be from fecal material — enteric microbes such as E. coli, Enterocci, Noroviruses (viruses that cause gastroenteritis) and, perhaps, Vibrio cholerae. The first three cause varying degrees of gastroenteritis, diarrhea, fever and vomiting. They are normally self-limiting and non-fatal. Individuals with weakened immune systems are more at risk, but would have to drink the water or have openings in the skin contact the contaminated waters.
Cholera would be present only if the fecal material from a previously infected person ended up in the waters.
— John Schwarz, Professor, Marine Biology, Texas A&M University at Galveston
• Can we eat the seafood?
The only seafood product at risk would be oysters harvested from mid-Louisiana eastward to Mobile Bay, and some reports indicate these are buried. There probably won’t be any oysters from this region for the next 18 to 24 months. The next natural set would be Spring 2006 and it takes up to two years to reach marketable size.
The oysters on the market in the interim will come from mid Louisiana westward to Texas. Consumers should be confident about the safety of the product.
Sammy Ray, Professor, Marine Biology, Texas A&M University at Galveston
The fish and shellfish of Texas’ Gulf and coastal waters have not been affected by Hurricane Katrina waters. Scientists are monitoring the situation and if there is an indication that humans could be affected by contaminants from Hurricane Katrina floodwaters, we will do our best to make sure the public is informed.
There are a couple of factors we try to keep in mind in situations like this. One is that bacteria and viruses that might cause human disease do not typically survive in seawater that is as salty as the Gulf of Mexico. Chemical pollutants are usually greatly diluted in the Gulf waters. Those pollutants tend to adhere to particles which fall to the bottom in the relatively deep, still waters of the Gulf. These two factors decrease the likelihood that fish along the Texas coast will become contaminated with chemical pollutants.
David Buzan, Coastal Studies Team, Texas Parks and Wildlife Department
We do not think there will be any detrimental effect. We will continue monitoring fecal coliform levels in Galveston for classification of shellfish water. If circumstances warrant, we can do additional monitoring of Gulf waters to determine if there are potential health risks.
Statement from Texas Department of State Health Service
• Can we expect an increase in Vibrio?
Vibrio vulnificus and Vibrio parahaemolyticus, both mentioned as being in the waters, are naturally occurring organisms in all bay waters along the coast. They are not a result of human waste pollution and they do not survive in full-strength seawater. Their natural levels in all bays are high during warm water seasons. Neither Vibrio would be detectable in Texas bays and coastal waters given the already high natural levels, even if they survived transport from Louisiana. Vibrio vulnificus is only a problem for high-risk individuals with diabetes, impaired liver functions or compromised immune systems who consume raw or undercooked shellfish.
Any enteric microbes present in the seafood would be purged with time spent in “clean” Texas waters. This isn’t the case with the Vibrios, which cannot be purged by spending time in clean waters. Cooking the seafood, however, removes all the microbes and ensures a safe seafood product for the consumer.
— John Schwarz, Professor, Marine Biology, Texas A&M University at Galveston
Texas coastal residents and others concerned about the state’s coastal areas can monitor the following web sites for additional information:
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For additional information, contact:
Dr. Norman Guinasso, Director
Geochemical Environmental Research Group
Texas A&M University
979-862-2323, ext. 114
guinasso@tamu.edu
Dr. Steven DiMarco
Associate Professor, Department of Oceanography
Texas A&M University
979-862-4168
sdimarco@tamu.edu
John Schwarz
Professor, Department of Marine Biology
Texas A&M University at Galveston
409-740-4453
schwarzj@tamug.edu
Sammy Ray
Professor, Department of Marine Biology
Texas A&M University at Galveston
409-740-4526
Dr. Lee Fuiman, Director
The University of Texas Marine Science Institute
361-749-6730
lee@utmsi.utexas.edu
Dr. Paul Montagne
Research Professor, Department of Marine Science
The University of Texas Marine Science Institute
361-749-6779
paul@utmsi.utexas.edu
NR 05-12
Powell 9/15/05
The Texas Sea Grant College Program is a partnership of university,
government and industry, focusing on marine research, education
and advisory services. Visit our web site at http://texas-sea-grant.tamu.edu
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