It’s been 53 years since the publication of Rachel Carson’s Silent Spring, a shocking exposé of chemical pollutants and their impact on the Earth's ecosystems.
As Carson alerted us in the book: "For each of us, as for the robin in Michigan, or the salmon in the Miramichi, this is a problem of ecology, of interrelationships, of interdependence. … We spray our elms and following springs are silent of robin song, not because we sprayed the robins directly but because the poison traveled, step by step, through the now-familiar elm-leaf-earthworm-robin cycle. These are matters of record, observable, part of the visible world around us. They reflect the web of life — or death — that scientists know as ecology."
Fast-forward over a half-century later and the fragile, interconnected living systems that provide everything we eat, drink, breathe and absorb are still under constant threat from much of the “progress” made during the Industrial Revolution.
In the ‘90s, scientists began sounding alarm bells about the health of the ozone layer and what that meant for the health of everything else: Most researchers concur that without the ozone layer, all life on earth would expire from overexposure to the sun’s UV rays. Since then, our understanding of the deleterious effects from holes in the ozone layer has been growing - sadly, along with the holes.
2012 marked the 25th anniversary of the Montreal Protocol, signed by 196 countries to limit the production of chlorofluorocarbons (CFCs) known to destroy the ozone layer. While 98 percent of Ozone-Depleting Substances (ODS) contained in nearly 100 hazardous chemicals worldwide have now been phased out (though NASA recently identified alarming amounts of an ozone-depleting compound called carbon tetrachloride — from an unknown source — decades after it was banned worldwide), the remaining 2 percent is a problem of increasing proportion. And a recent University of Leeds report finds that new ozone-destroying gases not controlled by the Montreal Protocol are on the rise.
One example is dichloromethane, aka methylene chloride, used widely cross-industry — including for the decaffeination of coffee and tea and to prepare extracts of hops and other flavorings. The substance is formed from several compounds that are very short-lived substances (VSLS) that break apart when they hit the stratosphere, damaging the ozone layer.
“This is important, as a molecule of ozone lost in this region has a far larger impact on climate than a molecule destroyed at higher altitudes by longer-lived gases,” said Dr. Ryan Hossaini, from the School of Earth and Environment at the University of Leeds, lead author of the study.
Methylene chloride appears naturally in oceanic sources, macroalgae, wetlands, and volcanoes, but the majority of it in the environment results from industrial emissions from paint strippers and removers, spray shoe polish, water repellents, wood floor and panel cleaners, wood stains, varnishes and finishes, heavy-duty surface cleaners and rust removers, glues and adhesives, etc. Industrial processes using methylene chloride include manufacturing of some pharmaceuticals, film coatings, metal cleaners and finishing solvents in electronics manufacturing.
In addition to its environmental impacts, papers on cancer and hepatic toxicity linked to methylene chloride were published in 1983, and links to neurotoxicity were identified four years earlier in Environmental Health Perspectives. When the chemical is breathed in, it affects the nervous system and brain and causes headaches, dizziness, nausea, clumsiness, drowsiness and other effects. When inhaled or absorbed through the skin, it can reach a fetus through the placenta and even enter breast milk.
Despite previous knowledge by the government and the scientific research community — not to mention the brands and businesses that profit from making products containing methylene chloride — only now is it being addressed in global treaties.
"VSLS can have both natural and industrial sources," said Hossaini. "Industrial production of VSLS is not controlled by the United Nations' Montreal Protocol, because historically these chemicals have contributed little to ozone depletion.”
Study co-author Dr. Stephen Montzka from the National Oceanic and Atmospheric Administration (NOAA) added: “The increases observed for dichloromethane are striking and unexpected; concentrations had been decreasing slowly in the late 1990s, but since then have increased by about a factor of two at sites throughout the globe.”
As holes in the ozone layer affect terrestrial and aquatic ecosystems, those toxic tentacles seep into biochemical cycles — and it’s a short step from chemicals in the environment to carcinogens in our food.
President Obama took a decisive step recently for greater food safety, combining the responsibilities of the Agriculture Department and the Food and Drug Administration under one roof, included within the Department of Health and Human Services, which already houses the FDA.
Food-borne illnesses strike nearly 46 million people, one in six, in the U.S. every year, resulting in 3,000 deaths according to the Centers for Disease Control and Prevention — and is on the rise. Currently, safety and inspection duties are handled by two distinct agencies: the Agriculture Department's Food Safety and Inspection Service (FSIS), in charge of meat, poultry and processed eggs; and the FDA, responsible for about 80 percent of other food supply issues. However confusion often arises: FSIS oversees processed egg products, but FDA oversees shelled eggs. The FDA oversees a pizza’s ingredients, unless it contains meat — then the USDA gets involved.
While Obama’s move to consolidate the bodies in charge of our food safety has ruffled Republicans’ feathers, others point out the need for more effective oversight.
"It's not about tradition. It's not about turf. It's about food safety," Agriculture Secretary Tom Vilsack recently said. "We have a system that no one can contend is as effective or efficient as it needs to be."