Dear EarthTalk: Is it true that nothing really “biodegrades” in a landfill? -- Laura, via e-mail

Organic substances “biodegrade” when they are broken down by other living organisms (such as enzymes and microbes) into their constituent parts, and in turn recycled by nature as the building blocks for new life. The process can occur aerobically (with the aid of oxygen) or anaerobically (without oxygen). Substances break down much faster under aerobic conditions, as oxygen helps break the molecules apart.

Most landfills are fundamentally anaerobic because they are compacted so tightly and thus do not let much air in. As such, any biodegradation that does take place does so very slowly. “Typically in landfills, there’s not much dirt, very little oxygen, and few if any microorganisms,” says green consumer advocate and author Debra Lynn Dadd. She cites a landfill study conducted by University of Arizona researchers that uncovered still-recognizable 25-year-old hot dogs, corncobs and grapes in landfills, as well as 50-year-old newspapers that were still readable.

Biodegradable items also may not break down in landfills if the industrial processing they went through prior to their useful days converted them into forms unrecognizable by the microbes and enzymes that facilitate biodegradation. A typical example is petroleum, which biodegrades easily and quickly in its original form, crude oil. But when petroleum is processed into plastic, it is no longer biodegradable, and as such can clog up landfills indefinitely.

Some manufacturers make claims that their products are photodegradable, which means that they will biodegrade when exposed to sunlight. A popular example is the plastic “polybag” in which many magazines now arrive protected in the mail. But the likelihood that such items will be exposed to sunlight while buried dozens of feet deep in a landfill is little to none. And if they do biodegrade at all, it is only likely to be into smaller pieces of plastic.

Some landfills are now being designed to promote biodegradation through the injection of water, oxygen, and even microbes. But these kinds of facilities are costly to create and as a result have not caught on. Another recent development involves landfills that have separate sections for compostable materials, such as food scraps and yard waste. Some analysts believe that as much as 65 percent of the waste currently sent to landfills in North America consists of such “biomass” that biodegrades rapidly and could generate a new income stream for landfills, marketable soil.

But getting people to sort their trash accordingly is another matter entirely. Indeed, paying heed to the importance of the environment’s “Three Rs” (Reduce, Reuse, Recycle!) is likely the best approach to solving the problems caused by our ever-growing piles of trash. With landfills around the world reaching capacity, technological fixes are not likely to make our waste disposal problems go away.

CONTACTS: U.S. Environmental Protection Agency (EPA) Reduce-Reuse-Recycle page; www.epa.gov/epaoswer/non-hw/muncpl/reduce.htm.

Dear EarthTalk: I’m going to be remodeling and was wondering, are there floorings or wall coverings available that won't aggravate my child’s respiratory problems? -- Mary, Lake Zurich, IL

For those with chemical sensitivities, the home is sometimes anything but a refuge. Volatile organic compounds (VOCs) such as formaldehyde can “off-gas” from carpets, wallpaper and paints, irritating lungs and promoting headaches and itchy eyes. Luckily, there are increasingly more options to traditional building materials and furnishings that are both kinder to Mother Earth and safer for our health.

For flooring, the Seattle-based Environmental Home Center recommends cork, linoleum, bamboo and selected hardwoods as the best choices from an indoor air quality standpoint. If you choose any of these options, make sure installers use non-toxic adhesives as the devil -- leaking VOCs -- is often in such details.

For those seeking something plusher underfoot, Earth Weave and Natural Home, among others, use natural fibers such as wool, jute, hemp and rubber to create attractive, chemical-free carpeting for both wall-to-wall and area rug applications. Both companies avoid toxic dyes and mothproofing as well as stain-repellents, relying instead upon the natural resiliency of the materials they incorporate.

And don't stop at the carpet. All-natural wool padding, which is usually needled together to avoid the VOCs often found in adhesives, will keep the top layer soft without introducing toxins to the underfoot mix. Traditional carpets and pads can off-gas a smorgasbord of noxious chemicals, including VOCs.

A raft of new wall-coverings has also come to the rescue in recent years. Most wallpaper is not made from paper at all, but from a malleable plastic called polyvinyl chloride (PVC), which generates several known carcinogens, including dioxin, during its production. One green alternative is Sherwin-Williams’ non-vinyl Easychange brand. Made from paper, it requires no special solvents or adhesives to install, and is stocked in a variety of designs and styles. Another good choice is Pallas Textiles’ DialTones line, made from discarded phonebooks. Also,

Environmental Home Center makes its own Innovations brand, which is made from nontoxic polyester and wood pulp, using water-based inks completely free of heavy metals.

In the paints category, there are now many non-toxic or low-VOC offerings, including AFM Safecoat, Livos, BioShield, Yolo and Olivetti. GreenHome.com stocks many of these, and mainstream paint dealers may carry eco-friendly paints from more familiar names, like Benjamin Moore or Sherwin-Williams.

Remodelers beware, though: Changing out your flooring and wall coverings won't banish chemical irritants entirely. Many homes built or remodeled during the 1970’s were insulated with formaldehyde foam, which can remain a health nuisance long after installation. Luckily, there are now plenty of greener insulation choices, such as cellulose, cotton and radiant metal barriers. Open-cell spray insulations such as Icynene or Air Krete are also popular with green builders, as they are effective, inexpensive and easy to apply. Some of these products are available at Home Depot and Lowe’s, but small green building supply retailers can be researched at GreenerBuilding.org.

CONTACTS: Environmental Home Center, www.environmentalhomecenter.com; GreenHome.com, www.greenhome.com; GreenerBuilding.org, www.greenerbuilding.org.

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