EarthTalk®
by the Editors of E/The Environmental Magazine
EarthTalk®
From the Editors of E/The Environmental Magazine
Dear EarthTalk: I know that local food has health and environmental benefits, but my local grocer only carries a few items. Is there a push for bigger supermarkets to carry locally produced food? -- Maria Fine, Somerville, MA
By eating locally sourced foods, we strengthen the bond between local farmers and our communities, stay connected to the seasons in our part of the world, promote crop diversity, and minimize the energy intensive, greenhouse-gas-emitting transportation of food from one part of the world to another. Also, since local crops are usually harvested at their peak of freshness and typically delivered to stores within a day, customers can be sure they are getting the tastiest and most nutritious forms of the foods they like.
Luckily for consumers and the environment, local produce and other foods are now more widely available than they have been for decades. The first national grocery chain to prioritize local producers, perhaps not surprisingly, was natural foods retailer Whole Foods, which was buying from local farmers and ranchers since it opened its first store in 1980 in Austin, Texas. Today each of the company's 270-plus stores in 38 U.S. states prioritizes local sourcing—so much so that its customers take it for granted. Whole Foods’ relationships and distribution arrangements with local producers serve as models for the leading national grocery chains, many of which are beginning to source some produce locally when the season is right.
Some are taking more initiative than others. Perhaps most notable is Walmart. Back in 2008 the company committed to sourcing more local fruits and vegetables to keep produce prices down and provide affordable, fresh and healthy choices. Today more than 2,800 Walmart Supercenters and Neighborhood Markets across the country rely on a diverse network of small local growers to provide produce—making Sam Walton's company the nation’s largest purchaser of local produce. During summer months, at least one-fifth of the produce available in Walmart stores is grown within the same state as the given store.
The company’s Heritage Agriculture program encourages farms within a day’s drive of one of its warehouses to grow crops that the company would otherwise have to source from so far away that freshness would be jeopardized and the fuel burned and greenhouse gases emitted in the process would be substantial. While the Heritage program currently accounts for only four to six percent of the company's total domestic produce sales, the company is aiming for 20 percent within the next few years.
Other big grocery chains aren’t far behind. Safeway, one of the top three grocery chains in the country, prides themselves on local sourcing, getting nearly a third of its produce nationwide from local/regional growers. In heavy agricultural regions like California, the figure can be as high as 45 percent. The company has also made a big push into organic products, just like its biggest competitor, Walmart.
If the chain grocer near you doesn’t do a good job stocking locally sourced food, there are alternatives. Community Supported Agriculture programs, in which consumers “subscribe” to the produce of a given farm by paying monthly dues that entitles them to a box of fresh produce every week, are more popular than ever, as are local farmers’ markets, food co-ops and independent natural foods markets. To find local food near you, visit the Local Harvest, which lists organic food sources by zip code and offers a wealth of resources for those looking to learn more about where their food comes from and how it is produced.
CONTACTS: Whole Foods, www.wholefoods.com; Walmart, www.walmart.com; Safeway, www.safeway.com; Local Harvest, www.localharvest.org.
Dear EarthTalk: How are wild turkeys faring in the U.S.? Occasionally I'll see some crossing the road, but how well could they be doing with all the development going on around them? -- Harley Barton, Hingham, MA
No one can be sure how many tens of millions of wild turkeys roamed what was to become the continental United States when the Puritans dined on them at the first Thanksgiving in 1621 near Plymouth Rock, but there were obviously enough of the birds to make them easy prey. By the late 1700s turkeys across the frontier were being harvested with reckless abandon. The food shortages that accompanied the Civil War accelerated demand for wild turkeys, and their numbers started to dwindle to startlingly low levels. By the early 1900s, only some 30,000 wild turkeys remained; the birds had been extirpated across almost half of their former range.
But things started to turn around for wild turkeys in the 1920s. For starters, millions of acres cleared by the pioneers began to regenerate into the type of woodland habitat where the birds could thrive. But the real boost for wild turkeys came in the form of legislation. At the urging of hunters, state wildlife agencies, and the firearms industry, Congress passed the landmark Federal Aid in Wildlife Restoration Act (Pittman-Robertson Act) in 1937, which placed an excise tax on guns, ammo and other hunting gear. A portion of the billions of dollars raised from the law have been and continue to be allocated toward restoring wildlife habitat across the country.
By 1959, wild turkey numbers jumped sixteen fold, topping half a million birds across the U.S. A 1973 wild turkey census by the then newly formed National Wild Turkey Federation (NWTF) turned up something like 1.3 million birds. NWTF, which was founded by hunters to aid in turkey conservation efforts, would turn out to be instrumental in shepherding the wild turkey's recovery by channeling hundreds of millions of dollars in charitable donations and grants into habitat recovery and bird relocation projects. Although the birds will likely never return to the population levels pre-dating white settlement, they haven't been healthier in 300+ years. These days as many as seven million wild turkeys roam the countryside and can be found in every U.S. state besides Alaska.
Of course, our success in restoring habitat for wild turkeys has also been beneficial for a wide range of wild animals. Conservations credit the visionary Pittman-Robertson Act (along with the hard work of dedicated wildlife managers) as instrumental in the recovery of not only wild turkeys but also once struggling populations of white-tailed deer, pronghorn antelope, wood duck, beaver, black bear, Canada goose, American elk, desert bighorn sheep, bobcat, mountain lion, and several species of predatory birds.
Besides the animals and biodiversity benefitting from species recovery, hunters can also rejoice, especially given that it has been their money that has funded many of the projects to restore habitat where they hunt. Turkey hunting is traditionally an autumn pursuit, culminating at Thanksgiving, of course, but each state has its own laws regarding when and where turkey hunting is allowed. NWTF provides a free online state-by-state “Fall Turkey Hunting Guide” with hunting season dates and other pertinent information to help hunters plan their next trip wherever it may take them in the continental U.S. The website also serves as an invaluable resource for information and resources pertaining to conservation, hunting and other topics related to wild turkeys.
CONTACT: National Wild Turkey Federation, www.nwtf.org.
Dear EarthTalk: I always thought cotton was eco-friendly, but I recently heard otherwise. What’s so bad about cotton? And where can I find organic cotton clothing? -- Jamie Hunter, Twin Falls, ID
There’s a lot “bad” about conventionally grown cotton—cotton grown with the aid of synthetic chemicals, that is. The Organic Trade Association (OTA), a nonprofit trade group representing America’s burgeoning organic cotton industry, considers cotton “the world’s dirtiest crop” due to its heavy use of insecticides. The nonprofit Environmental Justice Foundation (EJF) reports that cotton uses 2.5 percent of the world’s cultivated land yet uses 16 percent of the world’s insecticides—more than any other single major crop.
Three of the most acutely hazardous insecticides, as determined by the World Health Organization, are well represented among the top 10 most commonly used in producing cotton. One of them, Aldicarb, “can kill a man with just one drop absorbed through the skin,” says OTA, “yet it is still used in 25 countries and the U.S., where 16 states have reported it in their groundwater.”
Conventionally grown cotton also uses large amounts of nitrogen-based synthetic fertilizer—almost a third of a pound, says the OTA, to grow one pound of raw cotton. To put that in perspective, it takes just under one pound of raw cotton to make one t-shirt. Researchers have found that the fertilizers used on cotton are the most detrimental to the environment, running off into freshwater habitats and groundwater and causing oxygen-free dead zones in water bodies. The nitrogen oxides formed during the production and use of these fertilizers are also a major part of the agricultural sector’s greenhouse gas emissions.
This is all true despite that the use of sprayed insecticides is quickly decreasing with the advent of genetically engineered cotton seeds that have insecticides bred right into them. A third of global cotton cropland and 45 percent of world cotton production now uses genetically engineered seeds. This poses a whole other set of issues, as some scientists fear that the proliferation of such “Frankenseeds” can lead to pest immunities and even the unleashing of so-called “super pests” that can resist virtually any pesticide.
Organic cotton farming eschews synthetic chemicals (as well as genetically engineered seed) in favor of time-tested natural alternatives that ward off pests, replenish and maintain soil fertility and generally optimize growing conditions without compromising the environment or our health. “Composted manures and cover crops replace synthetic fertilizers; innovative weeding strategies are used instead of herbicides; beneficial insects and trap crops control insect pests; and alternatives to toxic defoliants prepare plants for harvest,” says the Sustainable Cotton Project (SCP), a nonprofit that helps cotton farmers in California’s Central Valley discover the economic, environmental and health benefits of avoiding synthetic chemicals.
For consumers able to pay a little more, there are now thousands of organic cotton retailers. The OTA reports that American farmers increased plantings of organic cotton by 26 percent in 2009 over 2008, while sales of organic cotton fiber grew 10.4 percent (to $521 million) during the same time. The OTA’s Organic Pages Online lists vendors (and links to their websites) by product type; many sell online as well as through retail chains. Even some big box stores now offer organic cotton items. So keep your eyes peeled and be a part of the solution by opting for organic cotton next time you stock up your drawers.
CONTACTS: OTA, www.ota.com; EJF, www.ejfoundation.org; SCP, www.sustainablecotton.org.
Dear EarthTalk: What are some simple things I could do to green the office I work in?
-- James Raskin, Framingham, MA
No matter how green your office may be already, there is surely room for improvement somewhere. Here are 10 suggestions to help get you and your co-workers further along on the path to office sustainability:
(1) Take your Office’s Green Footprint: The website TheGreenOffice.com, an online retailer specializing in green office products, makes available a free Office Footprint Calculator to gauge what kind of effect you and your co-workers are having on the environment and identify how to make improvements.
(2) Save Trees: The average office worker uses 10,000 sheets of copy paper a year. Refrain from printing when you can, use both sides of a sheet, and recycle so that the recycling industry will have raw material.
(3) Power Down: Artificial lighting accounts for almost half of all office electricity use. Turn off lights that are not being used. Better yet, install motion sensors that do it automatically when no one is in the room. Also, shut down computers overnight, and set them to go into sleep mode when sitting idle.
(4) Minimize E-Waste: Upgrade or repair the office computers instead of junking them. So-called “e-waste”—toxin-leaching computers and electronics—is a huge problem all over the world now.
(5) Telecommute: Encourage workers to work at home when possible to save car trips. For those who must come to the office, encourage bicycling if it is safe. Also some firms now subsidize employee public transit costs to discourage driving. And online video tools like Skype can help cut down on business trips.
(6) Green Screen Your Suppliers: Ask your vendors how they are greening their operations. Just posing the question can start them thinking, the precursor to action. Demand recycled paper and soy-based inks from your printers, and buy only green office supplies—which are now widely available.
(7) Clean Greener: Make sure your cleaning service uses non-toxic, green friendly products—if they don’t, offer to supply them—so that you can breathe easy when you’re trying to get your own work done.
(8) Eco-Renovate: If you need to renovate or upgrade anything, greenest options abound, including non-toxic paints, natural fiber carpeting, energy efficient windows and Energy Star-rated office equipment.
(9) Drink Tap Water: Having big jugs of water lugged in and out every week by the bottle water company is not only unnecessary but a big waste of energy. Most tap water is safe to drink; if yours isn’t or you’re not sure, put filters on the kitchen spouts or buy filtered water pitchers and keep them in the office fridge.
(10) Put Your Heads Together: Form a committee to organize and monitor your office’s green practices, to ensure that your office’s green goals don’t fall away if one or two committed employees move on, and to reinforce the importance of doing the right thing across the organization.
CONTACTS: TheGreenOffice.com, www.thegreenoffice.com.
Dear EarthTalk: Is the dairy industry really trying to stop soy milk makers from calling their products “milk?” They must feel very threatened by the preponderance of soy milks now available in supermarkets. -- Gina Storzen, Weymouth, MA
Indeed, just this past April the National Milk Producers Federation (NMPF), a trade group representing dairy farms, petitioned the U.S. Food & Drug Administration (FDA) to crack down on what it calls “the misappropriation of dairy terminology on imitation milk products.” NMPF has been asking for such a ruling for a decade, and argues that the soy industry’s “false and misleading” labeling is now more common than ever.
According to NMPF president and CEO, Jerry Kozak, the FDA has let the issue slide so that the meaning of ‘milk’ and even ‘cheese’ has been “watered down to the point where many products that use the term have never seen the inside of a barn.”
Furthermore, Kozak adds, the use of “dairy terminology” on non-dairy products can lead people to think they are eating healthier than they really are, especially because non-dairy products “can vary wildly in their composition and are inferior to the nutrient profile of those from dairy milk.”
The website FoodNavigator-USA.com reports that on the other side of the Atlantic, the European Dairy Association (EDA) has also called for the term ‘soy milk’ to be replaced with ‘soy drink’. EDA also suggests other options including ‘soy beverage’, ‘soy preparation’ and ‘soy-based liquid’. It’s no wonder the soy industry isn’t quick to give up the milk moniker, given how catchy the alternatives could be!
Jen Phillips of Mother Jones magazine takes issue with the dairy industry’s sense of ownership when it comes to terms like ‘milk’, ‘cheese’ and ‘dairy’. “The word ‘milk’ has lots of uses and has been used for non-dairy milks like coconut for a long time,” she reports, adding that consumers already know that soy milk isn’t dairy milk. “Instead,” she writes, “the move to ban ‘milk’ from non-dairy products is a transparent ploy by the NMPF to hurt the soybean industry that, thanks to increasingly health-conscious consumers and ethanol production quotas, is growing stronger every year.”
She also disagrees with Kozak’s claim that dairy milk is healthier than soy: “Actually, soy milk and dairy aren’t that different nutritionally, except for that milk is fattier,” she says, explaining that a cup of vanilla soy milk has 30 fewer calories than a cup of two percent cow’s milk. And while dairy does have twice the protein, soy milk has 10 percent more calcium. “It’s a bit of a toss-up nutritionally, but I'm lactose-intolerant so I’ll choose the ‘milk’ that doesn't make me gassy and crampy.”
Phillips adds that, since 90-100 percent of Asians and 50 percent of Hispanics—two of the fastest growing immigrant populations in the U.S.—are lactose intolerant, “NMPF might want to think less about fighting soy and more about how they’re going to deal with people who can’t drink milk to begin with.”
CONTACTS: NMPF, www.nmpf.org; FDA, www.fda.gov; FoodNavigator-USA.com, www.foodnavigator-usa.com; EDA, www.euromilk.org; Mother Jones, www.motherjones.com.
Dear EarthTalk: Many people oppose dams because they change the flow of rivers and affect the migrating patterns of fish and other species, but aren’t they also a great renewable energy source? -- Ryan Clark, Milton, WA
Hydroelectric dams are among the greenest and most affordable electricity sources in the world—and by far the most widely used renewable energy sources—but they also take a heavy environmental toll in the form of compromised landscapes, ecosystems and fisheries. Hydroelectric dams have been an important component of America’s energy mix since the powerful flow of rivers was first harnessed for industrial use in the 1880s. Today hydroelectric power accounts for seven percent of U.S. electricity generation—and some two-thirds of the country’s renewable power—according to the U.S. Geological Survey.
Globally, about 19 percent of electricity comes from hydroelectric sources. The U.S. Energy Information Administration reports that China is the world’s largest producer of hydroelectricity, followed by Canada, Brazil and the U.S. Some two-thirds of the economically feasible potential for hydro power remains to be developed around the world, with untapped resources most abundant in Latin America, India and China.
Of course, despite the inexpensive and emissions-free power, many environmentalists consider hydroelectric dams to be man-made abominations that prevent salmon and other fish from swimming upstream, divert otherwise natural riparian settings, and fundamentally change the character of surrounding ecosystems. Green groups including American Rivers, Defenders of Wildlife, Earthjustice, the Endangered Species Coalition, Friends of the Earth, National Wildlife Federation and the Sierra Club are pushing the federal government to mandate the removal of four dams along the Snake River in Washington State that help the region have the lowest power-related carbon footprint in the country. The dams have decimated once teeming salmon runs, and upstream forest ecosystems have suffered accordingly.
But the Bonneville Power Administration, the quasi-federal utility that runs the dams and distributes the electricity they produce, says that keeping them going is crucial even as wind plays an increasingly larger role in the region’s electricity mix. Since hydro power can be generated and released when most needed, it is an important resource for backup power when intermittent sources like wind (and solar) aren’t available.
The scheduled removal of two century-old dams on the Elwha River in Washington State’s Olympic National Park beginning in 2011 may well serve as test cases for larger dam removal projects in the Pacific Northwest and beyond. Planners hope wild salmon numbers will rebound as a result, and that other wildlife—such as bald eagles and black bears—will follow suit.
President Obama has committed $32 million to modernize existing hydropower dams, increase efficiency and reduce environmental impacts. “There’s no one solution to the energy crisis, but hydropower is clearly part of the solution and represents a major opportunity to create more clean energy jobs,” U.S. Secretary of Energy Steven Chu told reporters last year. “Investing in our existing hydropower infrastructure will strengthen our economy, reduce pollution and help us toward energy independence.”
CONTACTS: U.S. Geological Survey, www.usgs.gov; U.S. Energy Information Administration, www.eia.doe.gov; Bonneville Power Administration, www.bpa.gov.
Dear EarthTalk: Should I fear radiation exposure associated with medical scans such as CT scans, mammograms and the like? -- Shelly Johansen, Fairbanks, AK
The short answer is…maybe. Critics of the health care industry postulate that our society’s quickness to test for disease may in fact be causing more of it, especially in the case of medical scans. To wit, the radiation dose from a typical CT scan (short for computed tomography and commonly known as a “cat scan”) is 600 times more powerful than the average chest x-ray.
A 2007 study by Dr. Amy Berrington de González of the National Cancer Institute projected that the 72 million CT scans conducted yearly in the U.S. (not including scans conducted after a cancer diagnosis or performed at the end of life) will likely cause some 29,000 cancers resulting in 15,000 deaths two to three decades later. Scans of the abdomen, pelvis, chest and head were deemed most likely to cause cancer, and patients aged 35 to 54 were more likely to develop cancer as a result of CT scans than other age group.
Another study found that, among Americans who received CT scans, upwards of 20 percent had a false positive after one scan and 33 percent after two, meaning that such patients were getting huge doses of radiation without cause. And about seven percent of those patients underwent unnecessary invasive medical procedures following their misleading scans. CT scans are much more common today than in earlier decades, exacerbating the potential damage from false positives and excessive radiation exposure.
“Physicians and their patients cannot be complacent about the hazards of radiation or we risk creating a public-health time bomb,” says Dr. Rita Redberg, a cardiologist at University of California-San Francisco. “To avoid unnecessarily increasing cancer incidence in future years, every clinician must carefully assess the expected benefits of each CT scan and fully inform his or her patients of the known risks of radiation.”
CT scans are not the only concern. Mammograms are now routine for women over 40 years old. But some studies suggest that these types of screenings may cause more cancers than they prevent. Because of this, the federally funded U.S. Preventive Services Task Force now recommends that women not otherwise considered high risk for breast cancer wait until age 50 to begin getting mammograms—and then to get them every two years instead of annually. However, the American Cancer Society argues that such restraint would result in women dying unnecessarily from delaying screenings.
Women with a family history of breast cancer may be at greatest risk. Researchers from the University Medical Center Groningen in the Netherlands found that five or more x-rays—or any exposure to radiation—before the age of 20 for “high risk” women increased the likelihood of developing breast cancer later by a factor of two and a half.
Individuals should ask tough questions of their physicians to determine if and how much screening is absolutely necessary to look for suspected abnormalities. Our knowledge of the risks of radiation-based screenings will only help us to make more informed decisions about our health.
CONTACTS: National Cancer Institute, www.cancer.gov; American Cancer Society, www.cancer.org; University Medical Center Groningen, www.umcg.nl.
Dear EarthTalk: What is happening with various programs initiated over the years in the U.S. to return to the wild certain animal species that had been endangered or threatened? And do environmentalists tend to be for or against such efforts? -- Susan Adams, Owl’s Head, ME
From the standpoint of species and ecosystem health, limited attempts at predator reintroduction in the United States have for the most part proven very successful. The gray wolf, extirpated by hunters in the Yellowstone region some 90 years ago, is now thriving there in the wake of a controversial reintroduction program initiated in 1995, when the National Park Service released 31 gray wolves into the park’s expansive backcountry. Today as many as 170 gray wolves roam the park and environs, while the elk population—which was denuding many iconic park landscapes in the absence of its chief predator—has fallen by half, in what many environmentalists see as a win-win scenario.
Other reintroduction efforts across the U.S. have also been successful. From the lynx in Colorado to the condor in California to the Black-footed ferret on the Plains, scientists are pleased with how well reintroduced species have taken to their new surroundings. As a result, many conservationists now view the reintroduction of iconic wildlife species as key to restoring otherwise degraded natural landscapes.
“When we kill off big cats, wolves and other wild hunters, we lose not only prominent species, but also the key ecological and evolutionary process of top-down regulation,” says the non-profit Rewilding Institute, adding that the recovery of large native carnivores should be the heart of any conservation strategy in areas where such predators have disappeared. “Wolves, cougars, lynx, wolverines, grizzly and black bears, jaguars, sea otters and other top carnivores need to be restored throughout North America in ecologically effective densities in their natural ranges where suitable habitat remains or can be restored.”
Not everyone is so bullish on wildlife reintroduction programs, despite their success. As for the Yellowstone wolf reintroduction, ranchers operating on private land outside park boundaries still complain about the threat of free-roaming wolves poaching their livestock. In response, the non-profit Defenders of Wildlife has implemented its Wolf Conservation Trust whereby donated funds are channeled toward paying ranchers fair market value for any stock lost to wolf predation. The group hopes the fund will “eliminate a major factor in political opposition to wolf recovery” by shifting the economic burden of wolf recovery from livestock producers to those who support wolf reintroduction.
Some environmental advocates also oppose wildlife reintroductions. One argument is that people have “played God” enough and should stop tinkering even more with wildlife and ecosystems, especially given that the overall long-term impact is always uncertain. And some animal advocates dislike such strategies from a humanitarian perspective: “Reintroduction programs subject wild animals to capturing and handling, which is always stressful for them, and may eventually put them in the line of fire of farmers who are already angry about predator-reintroduction programs,” claims People for the Ethical Treatment of Animals (PETA), adding that, when predators are reintroduced to an area where they have long been absent, prey species tend to scatter and “their lives and behavior patterns are turned upside-down.”
CONTACTS: The Rewilding Institute, www.rewilding.org; Defenders of Wildlife, www.defenders.org; People for the Ethical Treatment of Animals (PETA), www.peta.org.
Dear EarthTalk: What are the differences between farmed versus wild salmon when it comes to human and environmental health? -- Greg Diamond, Nashville, TN
Salmon farming, which involves raising salmon in containers placed under water near shore, began in Norway about 50 years ago and has since caught on in the U.S., Ireland, Canada, Chile and the United Kingdom. Due to the large decline in wild fish from overfishing, many experts see the farming of salmon and other fish as the future of the industry. On the flip side, many marine biologists and ocean advocates fear such a future, citing serious health and ecological implications with so-called “aquaculture.”
George Mateljan, founder of Health Valley Foods, says that farmed fish are “far inferior” to their wild counterparts. “Despite being much fattier, farmed fish provide less usable beneficial omega 3 fats than wild fish,” he says. Indeed, U.S. Department of Agriculture research bears out that the fat content of farmed salmon is 30-35 percent by weight while wild salmons’ fat content is some 20 percent lower, though with a protein content about 20 percent higher. And farm-raised fish contain higher amounts of pro-inflammatory omega 6 fats instead of the preponderance of healthier omega 3s found in wild fish.
“Due to the feedlot conditions of aquafarming, farm-raised fish are doused with antibiotics and exposed to more concentrated pesticides than their wild kin,” reports Mateljan. He adds that farmed salmon are given a salmon-colored dye in their feed “without which their flesh would be an unappetizing grey color.”
Some aquaculture proponents claim that fish farming eases pressure on wild fish populations, but most ocean advocates disagree. To wit, one National Academy of Sciences study found that sea lice from fish farming operations killed up to 95 percent of juvenile wild salmon migrating past them. And two other studies—one in western Canada and the other in England—found that farmed salmon accumulate more cancer-causing PCBs and dioxins than wild salmon due to pesticides circulating in the ocean that get absorbed by the sardines, anchovies and other fish that are ground up as feed for the fish farms. A recent survey of U.S. grocery stores found that farmed salmon typically contains 16 times the PCBs found in wild salmon; other studies in Canada, Ireland and Great Britain reached similar conclusions.
Another problem with fish farms is the liberal use of drugs and antibiotics to control bacterial outbreaks and parasites. These primarily synthetic chemicals spread out into marine ecosystems just from drifting in the water column as well as from fish feces. In addition, millions of farmed fish escape fish farms every year around the world and mix into wild populations, spreading contaminants and disease accordingly.
Ocean advocates would like to end fish farming and instead put resources into reviving wild fish populations. But given the size of the industry, improving conditions would be a start. Noted Canadian environmentalist David Suzuki says that aquaculture operations could use fully enclosed systems that trap waste and do not allow farmed fish to escape into the wild ocean. As for what consumers can do, Suzuki recommends buying only wild-caught salmon and other fish. Whole Foods and other natural foods and high end grocers, as well as concerned restaurants, will stock wild salmon from Alaska and elsewhere.
CONTACTS: Health Valley Foods, www.healthvalley.com; USDA, www.usda.gov; David Suzuki Foundation, www.davidsuzuki.org.
Dear EarthTalk: I’ve been hearing about the great gas mileage for Volkswagens that use diesel fuel. But is it better for the environment to use diesel or unleaded gasoline? -- K. Cronk, Bay City, MI
In the past, diesel fuel was always considered dirtier than gasoline. But newer standards regulating sulfur content and improved technology in diesel engines have made diesel somewhat kinder to the environment. Many eco-advocates now tout diesel as a viable and preferable alternative to regular unleaded gasoline.
Where diesel fuel really shines over gasoline is improved fuel economy thanks to its higher “energy density”: Diesel contains more power per liter than gasoline. Today’s diesel engines have 20-40 percent better fuel economy than their gasoline counterparts, which some say more than makes up for the fact that they also produce about 15 percent more greenhouse gases. This greater efficiency means that diesel engines emit less carbon monoxide and carbon dioxide and fewer hydrocarbons than gasoline engines.
Diesel’s downside is that it emits larger amounts of nitrogen compounds and particulate matter (soot) that can cause respiratory problems and even cancer. The California Air Resources Board (CARB) attributes 70 percent of that state’s cancer risk from airborne toxins to soot from diesel cars and trucks. Nationwide, studies have shown a 26 percent mortality increase for those living in soot-polluted areas.
But diesel’s dark side is getting a little brighter, thanks to new technologies such as Mercedes-Benz’ BlueTEC system (now used in many VW, Audi and Chrysler diesel models) that filters particulates while improving overall engine performance. The Diesel Technology Forum (DTF), a trade association of carmakers, engine builders and petroleum distributors, reports that technologies now commonplace in new diesel engines reduce the tailpipe output of particulate matter by as much as 90 percent and nitrogen oxides by some 50 percent compared to diesel engines on the road just a decade ago.
“The industry has made significant strides in recent years to develop diesel systems that are cleaner and more efficient than ever before,” reports DTF. “Thanks to state-of-the-art engines, cleaner-burning fuels, effective emissions-control systems, and advancements in the fuel injection system, it would take 60 trucks sold today to equal the soot emissions of one 1988 truck.” U.S. Environmental Protection Agency (EPA) data shows that airborne diesel particulate levels fell by more than 37 percent during the 1990s.
Meanwhile, continually improving fuel efficiency standards in the European Union (where the majority of new cars purchased in many member countries use diesel fuel) are forcing carmakers to design more fuel efficient, less polluting vehicles around the world. After all, there’s no sense in designing better engines for one region with high standards and another for areas with less stringent rules. Another green benefit of diesel-powered engines is their ability to run on plant-derived biodiesel instead of petroleum-based diesel. And in the near future consumers may be able to shop for new diesel-electric hybrid cars now on the drawing boards of major automakers around the world. For now, consumers looking to buy a new or used car—diesel or otherwise—can see how different models stack up in regard to efficiency and emissions via the FuelEconomy.gov website, a joint effort of the EPA and the U.S. Department of Energy.
CONTACTS: CARB, www.arb.ca.gov; Mercedes-Benz’ BlueTEC, www.mbusa.com/bluetec; Diesel Technology Forum, www.dieselforum.org; FuelEconomy.gov, www.fueleconomy.gov.
SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk®, c/o E – The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; earthtalk@emagazine.com. E is a nonprofit publication. Subscribe: www.emagazine.com/subscribe; Request a Free Trial Issue: www.emagazine.com/trial.
Add Comment