This January, the FDA announced an important reversal of its 2008 claims regarding the safety of bisphenol-A, expressing new concern about "potential effects of BPA on the brain, behavior and prostate gland of fetuses, infants and children," and pledging to collaborate with other federal health agencies to reevaluate the chemical's safety.
Studying the effects of low-dose exposure is tricky, usually requiring a very large number of study subjects. Instead, epidemiologists tracking the problem frequently base their conclusions on data gathered from individuals known to have unusually high levels of a chemical-often the result of high-level occupational exposure. Halden insists that further study on low-dose exposure is essential to settle the matter of health risks, noting some evidence in the literature suggests that high-dose studies may be inadequate to properly understand toxic effects from continuous low-level exposures.
Halden explains that while plastics have legitimate uses of benefit to society, their brazen misuse has led to a radically unsustainable condition. "Today, there's a complete mismatch between the useful lifespan of the products we consume and their persistence in the environment." Prominent examples of offending products are the ubiquitous throwaway water bottles, Teflon-coated dental floss and cotton swabs made with plastic PVC sticks. All are typically used for a matter of seconds or minutes, yet are essentially non-biodegradable and will persist in the environment, sometimes for millennia.
Despite the scourge of discarded plastics and the health risks these substances pose, Halden is optimistic that society can begin to make wiser choices and develop more sustainable products, formed from biodegradable, non-toxic chemical building blocks.
New forms of polymer, some made from renewable materials that are digestible by microorganisms, are being explored.
Ultimately, converting to petroleum-free construction materials for use in smart and sustainable plastics will become a necessity, driven not only by health and environmental concerns but by the world's steadily declining oil supply. As Halden emphasizes, the manufacture of plastics currently accounts for about 8 percent of the world's petroleum use, a sizeable chunk, which ultimately contributes to another global concern-the accumulation of carbon dioxide in the atmosphere.
"We are at a critical juncture," Halden warns, "and cannot continue under the modus that has been established. If we're smart, we'll look for replacement materials, so that we don't have this mismatch-good for a minute and contaminating for 10,000 years."
Source: Arizona State University