What Are the Long Term Problems If DDD & DDE Are in the Water Supply?

DDT was developed to control insects that pose harm to humans or crops. In the U.S., this chemical has been banned since the early 1970s because it can collect in the adrenal glands and disrupt hormonal production. But it's still commonly used in other parts of the world to control mosquitoes that carry diseases harmful to humans. According to the Centers for Disease Control and Prevention, DDT, or its metabolites, DDD and DDE (called DDXs), can remain in the water, air and soil for more than 30 years.

Human Consumption

• DDT and products derived from its chemical degradation (DDXs) are still abundant in soil and water samples throughout the world. An article published in the June 2011 issue of "Environmental Toxicology and Chemistry" investigated the long-term effects of these compounds in areas bordering the Pearl River delta in southern China. The researchers found the majority of DDX compounds are in the soil, as shown by the concentrations found in fish food produced from crops grown in fields. The contaminants were up to four times greater in the soil than in the water samples tested in the study. However, the study concluded health effects to the fish were minimal, and the effects to humans consuming these fish were insignificant.

Reuse of Water With DDT

• DDT and its metabolites collect in sewer and storm-water basins that can re-enter the water supply through water treatment facilities. A study published in the March 2010 issue of "Science of the Total Environment" reported that DDT was detected in some catch basins in the state of Florida. The researchers found, however, that DDX amounts were minimal and did not pose significant threats to the environment or humans.

Unceertain Effects on Human Health in Some Areas

• According to an article published in the September 2009 issue of "Environmental Health Perspectives," the restrictions placed by the 2001 Stockholm Convention of Persistent Organic Pollutants were successful in limiting human exposure to DDT. However, the authors reported that the use of this substance was still ongoing in countries to control insects that carry human pathogens. The levels of DDT and its metabolites continued to be high in blood samples taken from people in these areas. The authors concluded that although these compounds may pose a risk to human health, not enough information was available, and further research was recommended.

Amazon River

• DDT was also used by the Brazilian government to control insects, and the chemical and its metabolites are found in fish caught in the Amazon River and consumed by humans. A January 2011 study published in "Environment International" described the concentrations of DDT and DDX in the flesh of fish captured in the rainy season in February or in the dry season in August. The study found that there was no correlation to the time of year when the fish were caught, and stated that levels were below the maximum established by the Swedish Food Regulation guidelines for human consumption.