The Truth About DDT

The Mississippi Levee Board, located in Greenville, has as its mission the protection of the lives and property of Delta residents. Since 1865, the Mississippi Levee Board has been diligent and conscientious in its effort to protect the public from flooding and keep citizens aware of water issues that might affect them.

In keeping with this effort, it is important that the public know the truth about dredging and the pesticide DDT. Recent fish advisories issued for the Delta by the Mississippi Department of Environmental Quality call for a limit on the number of fish consumed from certain area lakes and streams. The reason for these advisories pertain to levels of DDT contained in the fish that the DEQ maintains could be unhealthy if eaten in large quantities.

The following is a basic summary of the issues involved. The Mississippi Levee Board does not intend to act as a scientific source on these issues but believe these facts are accurate.


DDT was inexpensive, and relatively simple to produce, chemical that was the most effective weapon in combating diseases such as malaria and typhoid fever the world has ever seen. In fact, DDT is still used today in many Third World countries to control the spread of these diseases by mosquitoes.

QUESTION: Why is the DDT Fish Advisory occurring now instead of 30 years ago when DDT levels were 10 times higher than they are today?

ANSWER: Prior to 2000, the FDA set the action level for DDT at 5 parts per million (ppm) for restricting fish consumption. In 2000, the EPA adopted guidelines to be used for the evaluation of impacts for fisheries. In 2001, the MDEQ determined the need to restrict fish consumption if DDT levels exceed 1ppm. This action resulted in the need to issue advisories on many Delta streams, even though the same fish did not require action in 1999.

QUESTION: Will dredging of streams for flood control projects stir up DDT and increase the levels of the substance in fish causing problems to man and the environment?

ANSWER: No. Dredging actually removes contaminates from the stream and places it in a confined disposal area. The maintenance that the Mississippi Levee Board supports on the Big Sunflower River, and other projects, has many benefits to the environment, especially to the streams, rivers and fish population. Since fish testing has begun, both before and after the Steele Bayou Project, for example, DDT concentration in fish tissue has decreased by more than 85% in this project area.

Testing of fish tissue has shown that DDT levels were reduced significantly and are well below the 6.0-ppm-the EPA's limit for banning fish for human consumption-in the streams after dredging. Most of the fish tested, in fact, were below the 1.0-ppm limit for no restriction. The same type results are expected by the Mississippi Levee Board following the work to be done on the Big Sunflower River Maintenance Project.

DDT does not readily mix with water; it binds tightly to soil particles. Larvae insects and aquatic worms digest the organic material in the soil particles and bottom dwelling fish eat these organisms. Once the DDT is in the fish it builds up in its fatty tissue. Dredging removes sediment, including any with DDT content, from the stream bed. Dredging of contaminated sediments has been successfully performed in many areas around the country on similar EPA approved projects such as in the Puget Sound near Seattle and in New York Harbor. The EPA has also endorsed dredging both the Hudson River in New York and the Elizabeth River in Virginia to remove contaminated sediments. The Hudson River Project is very similar to the Big Sunflower River Project in that the Hudson River sediment is contaminated with PCBs, a DDT-like substance, and the PCB contamination has resulted in a fish consumption advisory for the past ten years. In EPA's judgement, the solution is to remove the contaminated sediments by dredging. In fact, former EPA director Carol Browner told reporters that the proposed dredging on the Hudson River will Òprotect the health of millions of families, fish and wildlife, rivers and estuaries."

The primary method by which the Big Sunflower River is to be dredged is known as Hydraulic Dredging. It is similar to a giant vacuum cleaner in that it sucks up the sediment with the attached DDT from the bottom of the stream and pumps it to confined disposal sites on high ground. Various disposal site designs will prevent DDT from reentering the environment. During dredging of the Big Sunflower River Maintenance Project, monitoring will insure activities meet the requirements of the water quality permit as issued by the Mississippi Department of Environmental Quality. The Mississippi Levee Board supports measures taken to protect and promote the health of the Delta people. However, they believe that facts must take precedence over fear, and that the whole story must be given concerning the relationship of flood control projects and their impacts on DDT levels in fish. Moreover, many opponents of Mississippi Levee Board flood control activities-projects that are designed to protect Delta citizens and their property from flooding -are using the issue of DDT as a fear tactic in order to stop these projects, such as the Big Sunflower River Maintenance Project.

The Mississippi Levee Board believes that facts, not rumors should be considered in public health issues. The problem of DDT should not be used as a deterrent to much needed flood control projects that will keep the Delta safe from flooding. The Levee Board believes that dredging provides a habitat that is proven to reduce the level of pesticides in fish. "We have, with the technology available today, the ability to construct these flood control projects in an environmentally sound manner," says Jim Wanamaker, Chief Engineer of the Mississippi Levee Board. "We believe it is important that such technology be used. Our purpose here at the Levee Board is to create solutions. To help us do that, we urge our Delta citizens to look closely at the facts and not be fooled by any misinformation being presented by others."

For more Information on the Mississippi Levee Board on any of its many projects, please call them at 662.334.4813.

Recent fish advisories issued by the Mississippi Department of Environmental Quality limit the amount of certain types of fish that can be safely consumed. However, some environmentalists and media sources have claimed that certain Levee Board Sponsored projects should be stopped, such as the Big Sunflower River Maintenance Project.

Don't be misled. Know the facts. Dredging will actually remove contaminates from our waters and is good for our region.

For more information, please give us a call.