Week of 05/09/10

Dear EarthTalk: I understand there’s an issue with the herbicide atrazine showing up in dangerous quantities in drinking water, mostly throughout the central U.S. Why is this happening and what’s being done about it?

—Marcus Gerde, Spokane, WA

Atrazine is an herbicide that is widely used across the U.S. and elsewhere to control both broadleaf and grassy weeds in large-scale agricultural operations growing corn, sorghum, sugar cane and other foods. While its use is credited with increasing agricultural yields by as much as six percent, there is a dark side. The nonprofit Natural Resources Defense Council (NRDC) reports that atrazine exposure has been shown to impair the reproductive systems of amphibians and mammals, and has been linked to cancer in both laboratory animals and humans. Male frogs exposed to minute doses of atrazine can develop female sex characteristics, including hermaphroditism and the presence of eggs in the testes. Researchers suspect that these effects are amplified when atrazine and other harmful agricultural chemicals are employed together.

Atrazine’s wide use makes its impacts that much scarier. NRDC reports that it is the most commonly detected pesticide or herbicide in U.S. waters, with the highest levels found in Indiana, Missouri and Nebraska. The Southeast also faces atrazine overload issues. What irks many public health advocates is that, even though study after study implicates atrazine in a long list of environmental and health problems, the U.S. Environmental Protection Agency (EPA) still allows farms to apply 75 million pounds of it each year. The European Union banned atrazine in 2004 due to persistent groundwater pollution there.

Critics of the EPA accuse the agency of selling out the health of the American people so industrial agricultural companies can make big profits. Indeed, in 2003, the EPA estimated a total annual economic impact, if atrazine were to be banned, of over $2 billion, including a yield loss plus increased herbicide cost averaging $28 per acre. In 2006, the EPA concluded that triazine herbicides (such as atrazine) posed "no harm that would result to the general U.S. population, infants, children or other…consumers."

Because of its application on crops such as corn, sorghum, sugar cane and other foods, the chemical atrazine is the most commonly detected pesticide or herbicide in U.S. waters, including drinking water supplies. Atrazine exposure has been shown to impair the reproductive systems of amphibians and mammals, and has been linked to cancer in both laboratory animals and humans.© Getty Images

In light of the EPA’s refusal to consider a ban on atrazine, NRDC and other groups have taken up the cause of educating consumers about the dangers posed by our national addiction to dangerous herbicides and pesticides, and lobbying elected officials to add their voices. President Obama has promised to take a hard look at atrazine, but it remains to be seen how long it will be before any such review takes place.

Of course, organic farmers aren’t waiting around for Obama to ban atrazine. By planting diverse crops, rotating them regularly and employing other age-old agricultural techniques, a new generation of American farmers is learning that expensive chemicals may not be able to boost their yields enough to warrant the high financial and environmental costs associated with constant chemical spraying.

As for you and I, the best way to prevent ingesting atrazine with our tap water is to buy a water filter that employs activated charcoal. NRDC publishes a free list of water filter recommendations on its Simple Steps website. If you’re on a well, NRDC recommends having its water tested annually for atrazine and other contaminants. Even bottled water producers may not filter out atrazine from their source aquifers, so filtering at the tap is the only way consumers can be sure to remove it along with other contaminants.

CONTACTS: NRDC; Simple Steps; EPA.

Dear EarthTalk: I’m told that, despite improvements in recent years, pesticides in flea collars are still harmful to pets and humans. Are there ways to minimize fleas without resorting to chemical concoctions? And is anything being done to ban these dangerous products from store shelves?

—Nancy Trouffant, Lancaster, PA

The Natural Resources Defense Council and other nonprofit groups convinced the federal government to ban six chemicals formerly common in flea collars, but two dangerous pesticides, tetrachlorvinphos and propoxur, are still used and are unsafe for humans and pets alike.© Michael, courtesy Flickr

Americans spend some $1 billion each year on products designed to combat fleas. Many of these products do their jobs handsomely, but two of the most egregious chemicals widely used in flea collars, tetrachlorvinphos and propoxur, have been shown to cause damage to our brains and nervous systems, and are known human carcinogens. Residues containing these chemicals can stay on a pet’s fur—and whatever he or she rubs up against, including your rugs, furniture and children—for weeks on end.

The Natural Resources Defense Council (NRDC) found that residue levels produced by some flea collars are 1,000 times higher than which the U.S. Environmental Protection Agency (EPA) considers safe for children to be around. Previous campaigning by NRDC and other nonprofit groups convinced the federal government to ban six other dangerous pesticides formerly common in flea collars, but tetrachlorvinphos and propoxur are still wreaking havoc on the environment and human and pet health.

In light of these dangers, what’s a concerned pet owner to do? For starters, ditch the collar and buy a flea comb. NRDC reports on its GreenPaws.org website that regular combing of a pet can help reduce fleas while allowing owners to monitor the extent of a given flea problem. Fleas caught in the comb should be drowned in soapy water. Also, vacuum frequently to rid your carpets, floors and crevices of fleas and their eggs. Dispose of any used vacuum bags immediately so fleas don’t escape and re-infest the room.

In the case of an extreme infestation, a professional steam carpet cleaning might be your best bet. As for your pet, frequent soapy baths are a great way to control fleas. Pet bedding should also be washed weekly in hot water. Outside of the house—where your pet romps and frolics—keep your grass and shrubbery clipped short to increase dryness and sunlight, which inhibits fleas. Nematodes—all-natural non-chemical biological agents available at most garden stores—will get rid of fleas in problem areas outdoors.

Of course, all this diligent work might still not be enough to keep fleas at bay, so you may need to turn to products formulated with essential oils that repel insects but do not harm pets or people. Be sure to start with small doses and monitor pets and family for allergic responses. Another non-pesticide option is S-Methoprene, a so-called Insect Growth Regulator which halts the growth of chitin, the substance that creates an insect’s exoskeleton, and won’t harm humans or pets. S-Methoprene is best used as a tool in preventing an extended infestation since adult insects are unaffected by it.

With the federal government apparently uninterested in banning tetrachlorvinphos and propoxur from flea products, NRDC is taking the issue straight to the people. Via its GreenPaws.org website, users can customize a letter to PETCO and PetSmart, the nation’s two largest pet supply retailers, asking them to stop selling products containing such dangerous chemicals. And whether or not these companies will heed the call may well depend on consumer behavior, so the more you buy safer alternatives, the better.


. EPA; NRDC; GreenPaws.org.

EarthTalk is now a book! Details and order information at: emagazine.com/earthtalkbook.