11 May 2007

POP Goes The Planet

By Rusty Rockets

The global warming debate has dominated the media over the past few years and things can only heat up further as governments are forced to address our rampant addiction to fossil fuels. And while most would agree that there's nothing wrong with making global warming a popular issue, there is a risk that other clear and present environmental issues are being eclipsed. But Melvin J. Visser intends to place a largely forgotten environmental issue front and center in our consciousness. His latest book, Cold, Clear, And Deadly: Unraveling a Toxic Legacy, outlines and attempts to fathom the mysteries behind what are known as persistent organic pollutants, or POPs.

POPs are organic compounds that are resistant to environmental degradation, allowing them to persist in the environment for long periods. In 1995, the United Nations Environment Programme (UNEP) compiled a shortlist of the POPs causing most concern, which included: dieldrin, endrin, heptachlor, hexachlorobenzene; and the much publicized polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDT). Since then, the list has grown to include many other compounds, such as certain flame-retardants and various organometallics (compounds that contain bonds between carbon and metal).

No doubt you recognize some of the above names, but do you know where POPs can be found, their prevalence, their source, how toxic they are and how damaging their effects can be? Don't worry if you don't, as you're not alone. Even top environmental scientists can't answer some of these curly questions with any certainty.

POPs like industrial PCBs and chlorinated pesticides were introduced just after the Second World War. Far from being considered even remotely dangerous, these compounds were seen as scientific panaceas, shown to improve anything from crop yields to fire prevention. For a time, POPs were being used everywhere without much in the way of regulation or oversight.

But this agricultural and industrial heyday was to end abruptly with the discovery that pesticide-related POPs and industrial PCBs - with the latter only being outlawed as late as 1978 - caused cancer in humans and had a devastating effect on wildlife. Despite these bans however, studies conducted by organizations such as the Swedish Environmental Protection Agency (SEPA) during the late 1990s showed that deadly levels of PCBs and dioxins continued to permeate the environment and our bodies.

SEPA's research demonstrated that even tiny amounts of these toxins can damage the brain, cause birth defects and trigger breast, testicular and prostate cancer. "[POPs] can disrupt hormonal systems and we suspect that they can contribute to birth defects and health damage in infancy," says SEPA's Niklas Johansson. "Furthermore, many factors are still unknown regarding the effects of organic pollutants. The picture is much more complex than hitherto believed and new substances are being discovered all the time."

Confirming SEPA's gloomy prediction, in 2006 the American Diabetes Association (ADA) found that POPs were linked to diabetes. After following the progress of over 2,000 test subjects - sourced from the National Health and Examination Survey between 1999 and 2002 - exposed to 6 common POPs, an ADA research team found that after adjusting for age, sex, race and ethnicity, poverty income ratio, BMI, and waist circumference; "There were striking dose-response relations between serum concentrations of six selected POPs and the prevalence of diabetes. The strong graded association could offer a compelling challenge to future epidemiologic and toxicological research."

Other researchers go as far as claiming that POPs in the environment may be responsible for many more cancers than once thought. "Organochlorines are persistent organic pollutants, which disperse over long distances and bioaccumulate in the food chain," says Professor Vyvyan Howard, of the University of Liverpool, UK. "For humans the main source of OC [organochlorine] exposure is from diet, primarily through meat and dairy products. Children are exposed to dioxin, a by-product of OCs, through food; dioxin and other POPs can also cross the placenta and endanger babies in the womb. Breastfed infants can be exposed to OCs with endocrine disrupting properties that have accumulated in breast milk. Our research looks at involuntary exposure to these chemicals in the air, food and water."

It is this lack of understanding regarding POPs surprising prevalence that led Melvin Visser and a team of international environmental scientists to investigate them more closely. Born in Grand Rapids, Michigan, and educated in chemical engineering at Michigan Tech, Visser describes himself as "a product of the Great Lakes Basin." After marrying into a commercial fishing family and working on a Lake Superior gill net tugboat, Visser fell for the harsh charms of the lake, and led an idyllic existence canoeing and hiking its many picturesque locales.

Visser's first professional experience was with the Upjohn Company, where he worked on the optimization of chemical processes, which he saw as: "a wonderful opportunity to learn the behavior of chemicals in the controlled environment of manufacturing equipment." But changes in his career path were to reveal a dark secret affecting his beloved Lake Superior.

Visser was appointed as the head of a unit responsible for compliance to newly emerging environmental laws and regulations, in regard to the use and phasing out of POPs. During this time, Visser was exposed to knowledge gleaned from various Great Lakes environmental campaigners, who, he claims, revealed to him that: "chemicals in the environment were devastating the gulls, cormorants, eagles and trout of Lake Superior." But Visser wondered how it could be that even after the banning of POPs, their levels in waterways remained constant. Call it serendipity, providence, or destiny, but after retiring in 1995, Visser was left with a POPs conundrum that was to lead to a moment of clarity, and the penning of Cold, Clear, And Deadly.

A big component of the POPs dilemma is a relatively simple one; the POPs ban is not global. Visser's team discovered that POPs used for agricultural and industrial purposes in developing countries were traveling north and dispersing themselves across the globe. According to Visser's calculations, the POPs wafting over the vast populations of Europe and North America are equivalent to over 100 million POP molecules per adult human breath - more than enough to be dangerously toxic to man and beast alike.

Mopping up the POPs that still exist, and controlling the inadvertent development of new POPs in Western nations is obviously critical, but unless we can tackle their widespread use in the developing world, our efforts may be for naught. As Visser points out, we cohabit one world, and our neighbor's environmental problems are also our own.

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