The Chemicals That Came to Stay
- Part 7

Erika Schreder has worked for the Washington Toxics Coalition as a staff scientist since 1997. She has a master’s degree in resource ecology and management and a B.S. in molecular biology. She currently directs the Clean Water for Salmon campaign, which aims to end pesticide uses that pollute water and threaten salmon.

Editor’s Note: Whatcom Watch will publish most of the 64-page report “Pollution in People” released May 2006 by the Toxic-Free Legacy Coalition. The entire report is available as a pdf file at http://www.pollutioninpeople.org.

Part 7

Rachel Carson taught us that lesson more than 40 years ago, when she issued a wake-up call in her book “Silent Spring.” Pesticides like DDT, then in common use for everything from mosquito control to orchard spraying, were not breaking down into harmless chemicals after their use. Instead, as Carson pointed out, the chemicals were building up in soil and sediment, fish and wildlife, threatening to destroy the very fabric of life.

For the Pollution in People study, we tested for DDT and PCBs, two chemicals that were long ago banned but continue to haunt us. These chemicals persist in the environment and our bodies. Women pass them on to their children in the womb and through breast milk. And as each of us ages, our load of these chemicals increases.

Rev. Ann Holmes Redding sees this chemical contamination as a corruption of the sanctity of life. As an Episcopal priest, Ann believes our bodies are a gift from a higher power and that we have a responsibility to care for them. But for nearly her entire life, Ann’s body has been home to unwelcome chemical imposters like DDT and PCBs. Her Pollution in People study results showed that she has 8.7 ppb DDT, a level high enough to put her in the top 25 percent of people nationwide. She also carries 1.5 ppb PCBs, again at the high end of national exposures.

DDT was first developed as an insecticide in the 1940s, and it was widely used during World War II to combat insect-borne diseases, such as malaria and typhus. After the war, DDT’s effectiveness, persistence and low cost made it popular for agricultural and commercial uses. In 1959, at the height of its popularity, 80 million pounds of the chemical were applied to forests, fields and gardens (USEPA 1972). Over DDT’s 30-year history in the United States, more than a billion pounds were used (USEPA 1975).

EPA banned nearly all domestic uses of DDT in 1972. Today, its use is limited to malaria control programs in some developing countries. But most of us are exposed to DDT every day because it is in so much of the food we eat (USDA 2006). Vegetables, meat, fish and dairy products all contain DDT, but animal and fatty foods contain the highest levels because the chemical is stored in fat and increases in concentration as it moves up the food chain (ATSDR 2002). Children, breast-feeding infants, and people living in the eastern Arctic have the greatest ongoing exposures to DDT from food.

Exposure to DDT is harmful to the nervous system, with high levels causing dizziness, tremor, irritability and convulsions (ATSDR 2002). Animal studies have found that low levels can affect nervous system development. In addition, people who applied DDT in occupational settings have suffered lasting neurological problems, performing tasks more slowly and displaying delayed reaction times, less dexterity and strength and reduced cognitive function (van Wendel de Joode 2001).

DDT is also considered a hormone-disrupting chemical because of its estrogen-like properties, and researchers have found disturbing effects in this regard. Mothers with greater exposure to DDT are more likely to have premature or small-for-gestational-age babies than mothers less exposed to the chemical (Longnecker 2001). Mothers with more DDT also breast-feed for a shorter period, possibly because DDT mimics hormones that inhibit milk production (ATSDR 2002). Animal studies have found that DDT causes cancer, and EPA ranks DDT as a probable human carcinogen.

PCBs had a more obscure purpose, but the chemicals made a name for themselves, nonetheless. Between 1929 and the mid-1980s, PCBs were popular as cooling fluids in electrical equipment and machinery because of their reputation for durability and fire resistance (USEPA 1979).

Concerns about PCBs’ health effects and persistence surfaced in the 1970s, and Monsanto, the major U.S. manufacturer of the chemicals, stopped producing them in 1977. The EPA phased out most uses of PCBs shortly thereafter. Levels of the chemical in people and wildlife have since declined, but three decades later we continue to ingest PCBs when we eat fish, meat or dairy products (ATSDR 2002).

Because PCBs accumulate in sediment in rivers, lakes and coastal areas, fish contain particularly high levels of the chemicals. Levels in fish can be 2,000 to more than a million times higher than levels in surrounding waters (USEPA 1999). Because of PCB contamination, the Washington State Department of Health recommends limiting consumption of fish and shellfish from many of the state’s waterbodies (WDOH 2006).

Women who consume PCBs in their diet readily pass them to their children in breast milk: infants may get 6 to 12 percent of their lifetime exposure to PCBs from breast-feeding alone (ATSDR 2002). At levels typically found in women and children around the world, PCBs can have profound effects on intellectual development.

In studies of large numbers of children in the U.S., Germany and the Netherlands, those with greater prenatal exposures (measured by levels in umbilical cord blood or the mother’s blood) performed worse on tests of brain development than children with lower exposures (Shantz 2003). The same body of research also revealed lower birth weights and slower growth in children with higher PCB levels. In each of these studies, the mothers of the most exposed children obtained PCBs from fish or other common sources.

Researchers who followed children in Michigan from birth to age 11 found that these effects persist (Jacobson 2002). They compared children from sport-fishing families, whose mothers ate above-average amounts of Lake Michigan fish, with children whose mothers ate no Lake Michigan fish. The sport-fishers’ children, who had greater prenatal exposures, showed intellectual deficits as infants, at age 4, and again at age 11, when they displayed attention deficits, lower IQs and poorer reading comprehension. While the mothers of the most-exposed children in this study had PCB levels several times those of our participants, other studies have found similar effects at lower levels (Shantz 2003).

In addition to cognitive damage, PCBs cause tumors in laboratory animals (Ross 2004) and have been classified by the EPA as probable human carcinogens. Studies suggest the chemicals are also toxic to the immune system, reproductive organs and thyroid. PCBs are a major contaminant in Puget Sound, and evidence is accumulating that they are a serious threat to the sound’s wildlife, too. Puget Sound’s endangered orca whales have accumulated PCBs to the point that they rank among the most contaminated marine mammals in the world (Ross 2006). Levels in orcas already exceed those needed to cause health effects such as immune system depression.

The histories of DDT and PCBs are both success stories and cautionary tales. Since these chemicals were banned 30 years ago, levels in our bodies have declined. And yet, we still face levels that could be causing harm — decades after regulatory action.

To this day, runoff from agricultural lands transports DDT-containing sediment to rivers and streams, where it’s taken up by fish. PCBs persisting in river and bay sediment cause astonishingly high levels in orca whales and salmon. As a result, both chemicals persist in our diets.

With both DDT and PCBs, the EPA allowed production and use to go on far too long, to the point where our air, water, land and bodies became so contaminated that decades of cleanup efforts have yet to eliminate their threats to our health. And the incredible sums expended by state, federal and tribal governments are all too often resources that could have been put to other uses had these chemicals been adequately tested and analyzed before their widespread production.

Governor Christine Gregoire has launched a major initiative to restore and protect Puget Sound, with the goal of solving the sound’s biggest pollution problems by 2020. Because cleaning up contaminated sediment is incredibly expensive, the 2006 Washington State Legislature appropriated $44 million for just a single year of Puget Sound cleanup and restoration activities.

This initiative is a bold step toward addressing the problem of historical pollution in Puget Sound. However, to fully restore the health of Puget Sound and other toxic sites, state government must place equal or greater priority on preventing the sound’s recontamination with these banned chemicals — as well as other persistent toxic chemicals, like PBDEs and perfluorinated compounds. §

For references, go to: http://www.pollutioninpeople.org pages 62-66.

Next Month: The Laws That Fail Us, and a Better Way