Comment ▼ Emerging chemical contaminants If we are going to live so intimately with these chemicals, eating and drinking them into the very marrow of our bones, we had better know something about their nature and power. —Rachel Carson (1962), Silent Spring fell in love with chemistry as a sophomore in high school at about the same time I fell in love with girls. But it wasn’t until college and a summer job as a chemical engineering intern at the local power station that I first came to respect chemicals. One of my jobs was testing transformer and capacitor oils in the dimly lit bowels of the power plant, where I practically bathed myself in PCB-laden oil until finally reading the label and learning better. Shortly after that, my eyes were opened to the risks that chemicals can pose when I read Rachel Carson’s book. I fell in love again, this time with the environment. Doesn’t it seem that we’ve been struck recently by a rash of “chemicals of the month” that have somehow slipped through the safety net protecting human and ecosystem health? In September, a study released by the Environmental Working Group (EWG), a nonprofit environmental research organization, caused a huge stir. Scientists working with EWG tested the breast milk of 20 women across the nation and found levels ranging from 9.5 to 1078 parts per billion (ppb) of polybrominated diphenyl ethers (PBDEs). PBDEs are used as flame retardants for a wide variety of fabrics, draperies, clothing, and carpeting, and they are heavily used in the United States, which has the world’s toughest flame retardant standards. Linda Birnbaum, director of the Experimental Toxicology Division of EPA’s National Health and Environmental Effects Research Laboratory, was quoted as saying the levels of PBDEs in humans are doubling every 2–5 years. Breast-feeding women are furious. Undoubtedly, these chemicals save many lives by preventing fires, but the public has come to demand chemicals that do not move into the environment, their bodies, and their babies. Perchlorate is another case in point. It now contaminates groundwater in 23 U.S. states, much of the lower Colorado River, and several aquifers in the desert Southwest. Manufactured since the early 1950s as an oxygenate in rocket fuels and firecrackers, it is also a natural component of Chilean nitrates used as fertilizer. Perchlorate (ClO4– ) is mobile in the environment and is considered toxic in the parts-per-billion range. Analytical techniques
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© 2003 American Chemical Society
for perchlorate improved in 1999, allowing detection where none was possible before. So far, EPA has not been able to establish a Maximum Contaminant Level (MCL) drinking water standard for perchlorate, and most of the states are scrambling with tentative standards set at 1–18 ppb to deal with groundwater and drinking water contamination and an irate public. Perfluorochemicals (perfluorooctane sulfonates, PFOS; and perfluorooctanoic acid, PFOA) offer additional evidence of chemicals slipping through the safety net. PFOS is thought to result from stain-resistant polymers used in carpet and fabric protection. The precursor chemicals for PFOS were voluntarily removed from such products by 3M in 2001, but somehow PFOS are showing up in fish and human blood sera around the world. PFOA is used as a monomer in Teflon production. These perfluorochemicals are persistent, toxic, and mobile in the environment. Today they are readily detected by rapidly improving analytical techniques—many of which are published in this journal. The newly emerging chemicals are not final products themselves but rather are intermediates, inerts, or used in the protection of other products. EPA has not been able to keep up with them. It has been 26 years since implementation of the Toxic Substances Control Act. Shouldn’t we have moved past this stage? In the United States, we have adopted the risk assessment paradigm and, for the most part, it has served us well, but we are behind in screening thousands of chemicals in use. We have experimented with voluntary approaches such as the American Chemistry Council’s Responsible Care program and with the voluntary testing of 2800 high-production-volume chemicals. We have criticized the European Union for its use of the Precautionary Principle and the extensive (expensive) Registration, Evaluation, and Authorization of CHemicals (REACH) program to test 20,000–30,000 chemicals anew. If there is a more cost-effective course of action, now is the time for government and industry alike to redouble their efforts. Let’s get on with our testing programs, if not voluntarily, then with further regulations to protect the environment and public health.
Jerald L. Schnoor, Editor (
[email protected])
NOVEMBER 1, 2003 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 375 A
