Skip to content
Join our Newsletter
Join our Newsletter

Farming's toxic legacy

Washington State soil tests positive for banned chemicals

High Country News

YAKIMA, WASHINGTON - Nothing about the quiet summer morning suggests a reason to worry.

Two-year-old Kian plays happily in the dirt of the empty lot where his family's new house will eventually stand. Nearby, his mother Tara Compton points out interesting "buggies," and when he toddles down the steep hillside, she holds his hand. Dust rises from the soil as though from a phantom stampede, and dirt covers the little boy's hands and face.

"This is where I plan to grow our garden," says Compton, pointing to a wide plot of earth near a peach tree that yields delicious fruit. She's pregnant, but with her tall, strong build, it hardly shows. "It's important to me to grow a lot of our own vegetables because it's so hard to know what's in the food you buy at the store."

Compton, a 38-year-old intensive care nurse, is a conscientious mother. She buys organic produce, filters her water and uses lotions and sunscreens that are paraben-free. Compton and her husband, Ron, who's studying to become a teacher, chose Yakima out of a host of Western cities largely because of the nearby hiking and camping opportunities. Yet despite the natural beauty and the good, clean living, their new home hides a potential threat to her children - one that Compton is hard-pressed to control.

Some 30 years ago, this upper-middle-class neighborhood, with its two-story brick houses and generous views of Mount Adams, was all orchards and farmland. In this way, Yakima resembles many communities. Over the past 28 years, more than 5.5 million acres (22,300 square kilometres) of former farmland in the West have been plowed under and transformed into subdivisions, schools and parks. But even though the apple trees and cotton fields are long gone, they can leave a hidden toxic legacy.

Throughout much of the 20th century, farmers in Yakima and across the country blanketed crops with now-banned pesticides, including lead arsenate and a suite of long-lasting, synthetic organic compounds laced with chlorine, such as DDT, dieldrin, toxaphene and chlordane. Today, decades after they were sprayed, these compounds and their breakdown products often persist in the soil.

That doesn't necessarily mean they're harming people; in many places, the levels are likely negligible. There are no immediate health effects associated with exposure to these chemicals in the soil. And existing research indicates that the known health risks of living on former agricultural lands are relatively low - especially where the soil has been capped with a grassy lawn. Still, children who are exposed regularly over a long time period to contaminated dirt through direct contact - perhaps by playing in it or gardening or eating vegetables grown in it - may develop cancer or other health problems decades later, according to the Environmental Protection Agency.

Washington State has decided that low risk is not the same as no risk. Since 2006, it has spent close to $7 million removing soil from 20 elementary schoolyards in the central part of the state, wherever lead and arsenic, the primary components of lead arsenate, exceeded levels set by the state to protect human health. The project - which includes some Yakima schools - is unique in the West.

Because the dangers posed by legacy pesticides are insidious and poorly understood, agencies and advocacy groups have focused on more obvious threats. Neither the federal government nor any Western state requires testing the soil prior to development of privately owned farmland, leaving the burden on landowners like the Comptons.

Meanwhile, real estate agents say it's the buyers' responsibility, not theirs, to find out about possible pesticide contamination. A survey of over 20 national environmental groups, including ones that focus on pesticides, reveals that none are working to change this dynamic.

"As a nation, we're flying blind on this issue," says John Wargo, Yale University professor of environmental risk analysis and policy. "The Environmental Protection Agency is so overwhelmed by new chemicals and managing the changing science on existing chemicals that are licensed that they're interpreting the ban (on legacy pesticides) as having solved the problem. That's shortsighted. We're not even asking questions, we're not doing the testing, and the result is people are being exposed without their knowledge and certainly without their consent."

A hundred years ago, land speculators lured people to plant orchards in the Yakima area with promises that "here fortunes grow on trees."

Hand-colored postcards from that era depict row after row of verdant orchards, neat fields and two-story white-painted homes. Ads in East Coast newspapers touted Yakima as the "orchard city," where "ten acres in fruit makes a man independent for life."

But that abundance did not come naturally. It relied on pesticides like lead arsenate, which helped control insects like the codling moth, an apple-loving scourge that thrives in the West's arid climate.

"Without lead arsenate, there would be no industry," says Frank Peryea, professor emeritus of soil science at Washington State University and one of the nation's foremost experts on arsenical pesticides. At the university's tree fruit research center in Wenatchee, a few hours north of Yakima, Peryea snaps a small unripe apple from a tree and slices it open with a pocketknife. These trees have not been treated with modern pesticides or pheromones, which disrupt the moths' mating cycle. Where the white flesh of the apple should be is a crater filled with the moth larvae's black excrement. "You want to eat that?" Peryea asks dryly.

Nope. Neither did consumers in the early 1900s. When researchers first introduced lead arsenate, farmers quickly became hooked on it, using handgun sprayers to coat apples, potatoes, cotton, cherries and other crops. Not only did the U.S. Department of Agriculture recommend spraying crops, but if growers didn't do so, state pest control boards in Oregon, Washington and California would spray for them - and charge the farmers for the effort, put a lien against their land, or even remove their trees. As early as 1915, the bugs had developed some resistance; farmers responded by spraying more. In 1941, U.S. farmers sprayed more than 60 million pounds of lead arsenate.

Then, in the late 1940s, American farmers abandoned their old standby in favor of DDT, then hailed as the savior of mankind. By the early '70s, an estimated 1.35 billion pounds of DDT had been sprayed in the U.S. - enough to fill more than 238 Olympic-size swimming pools. But public outcry against the pesticide began building after the 1962 publication of Rachel Carson's Silent Spring, which reported that DDT accumulates in living tissue in greater and greater concentrations as it moves up the food chain. Soon, other scientists linked the chemical with the near extinction of many birds. Several notable studies, presented to the nascent EPA, showed that DDT could cause cancer in humans. The EPA banned the chemical in the U.S. in 1972, and by 1990 had followed suit with lead arsenate and most other organochlorine pesticides.

Unfortunately, the very thing that made organochlorine pesticides like DDT effective for a long period of time also makes them hard to get rid of. Because chlorine binds strongly to other elements, the compounds are stable and do not break down easily. Organochlorines also bind to organic matter in soil, and to the fat cells of the organisms that consume it. When they eventually do degrade, they can break down into other toxic compounds. Lead arsenate, meanwhile, is composed of lead and arsenic, the party lingerers of the elements. Neither breaks down over time. They also bind to organic matter in the soil and don't dissolve readily in water, so rain can't easily wash them away. All of these chemicals can remain in the top 12 to 18 inches of the ground for decades - perhaps even hundreds of years.

Though no one has comprehensively sampled Western soils for legacy pesticides, during the 1990s, the U.S. Geological Survey looked at streambeds and fish across the nation, including every Western state. In watersheds where more than 50 percent of the land was in agriculture, DDT and its breakdown products, DDD and DDE, were present in sediment at half the sampled sites as well as in the tissue of 90 percent of sampled fish. Dieldrin was present in sediment in 17 percent of the sampled sites and in 63 percent of the fish. And while levels of both pesticides in fish tissue have dropped by 50 percent since they were banned for agricultural use in the '70s, research published in the past five years shows that this trend has flat-lined for DDT in some lakes. It could be that a certain amount of the compound is not degrading, or there may be continuing input of DDT from the atmosphere or watershed.

The fact that these chemicals persist in the environment means they're still finding their way into our bodies. DDT, dieldrin and other organochlorine pesticides are commonly found in the fatty tissues, and even in the breast milk, of people throughout the country, including those born decades after the compounds were banned. People can be exposed to these toxic chemicals through the water and air, or through touching or ingesting them in soil and food. Long-term, chronic exposure to various organochlorine pesticides is associated with damage to the central nervous system, liver, kidney and thyroid. The EPA classifies all as probable carcinogens; many are suspected endocrine disruptors, which mimic or block hormones that regulate metabolism and neurological and sexual development, and can cause various ailments.

Long-term exposure to lead arsenate, meanwhile, may elevate the level of lead in the blood, which is associated with learning and behavioral problems. Ingesting arsenic - most of the research has been done on people exposed through drinking water - can cause bladder, lung, liver, prostate and kidney cancers. Simply touching inorganic arsenic, however, does little more than irritate the skin, according to the Agency for Toxic Substances and Disease Registry.

Because their bodies are small and still developing, children, especially in the womb, are most vulnerable to the harmful effects of chemicals. They're also more likely to be exposed, since kids love to play in the dirt and toddlers put everything in their mouths, including soil.

But it is impossible to predict whether a particular individual will get sick.

So the EPA has projected the risk for an entire population, setting screening levels based on how much of a specific chemical, over an exposure period of 30 years, will cause no more than one person in 1 million to develop cancer. State and federal agencies can use these levels when considering cleanup of contaminated areas. But the standards aren't enforceable; there's no law saying that soil can't contain X amount of a particular compound. Nor does the EPA have any department or staff to deal with mitigating threats posed by legacy pesticides in converted farmland. The agency does, however, investigate and oversee cleanup of indisputably and severely contaminated land.

And last month, the EPA released a draft of its guidelines for locating new schools to protect children from environmental hazards. Though the document does suggest that sampling for banned pesticides in the soil of proposed school sites may be appropriate, it's not required and doesn't apply to existing schools.

"We've done our job, we've cancelled these pesticides," says a staffer in the EPA's Office of Pesticide Programs, who spoke on condition of anonymity. The agency lacks a mandate from Congress to assess potentially toxic products once they are removed from commerce, the staffer explained. "We know they're hanging around but there is nothing further we can do."

Without federal leadership, most Western states are caught in a bizarre catch-22. Because there are no acute toxic effects from contaminated soil - because kids aren't eating dirt and getting immediately, obviously sick - people are not necessarily even aware of the old pesticides in their backyards. But unless homeowners complain or state legislatures mandate action, state agencies say that they can't devote resources to the problem, especially given the long list of more pressing toxic threats.

All of this makes it even harder to raise the public awareness that might lead to the allocation of funds for cleaning up contaminated soil.

Washington is an exception; so is California, which requires the evaluation of soil for pesticides at any school using state funds for construction. Washington, Oregon and California have guidance documents that recommend residential developers hire environmental consultants to evaluate potential agricultural contaminants before building. But all are voluntary. No Western state mandates testing. And while some states have catchall requirements to disclose known contamination, only Colorado, Arizona, Washington and Nevada specifically require sellers to disclose legacy pesticide contamination if they find it, according to state agencies.

Some environmental consultants who spoke off the record say they've seen sellers avoid soil testing because they'd rather drop the asking price on property than incur potential liability. However, state environmental agencies say the lack of oversight and public awareness probably isn't a problem, because the Federal Deposit Insurance Corp. has required banks to evaluate potential pollution when reviewing loan applications for new development since 1993.

But banks may have been an imperfect safety net, especially during the recent housing boom, says Richard Renken, banks and trusts program manager for the Oregon Division of Finance and Corporate Securities, a state agency. "If Bank A wants an environmental assessment done, with all those extra costs, while the bank down the street just wants a property appraisal and the costs are lower (there), where do you think a developer will go?" asks Renken. "Plus, if someone wants a loan for an existing single family home that's 15 years old, even if 35 years ago someone sprayed DDT on it, it's already been long in a different use. No one's going to look."

Due to this collision of factors, the Comptons had no idea that their property had been an orchard until a neighbor told them. "I don't know what to do now," Tara Compton says. "I've been working in the soil and especially since I'm pregnant - what have I been doing that could affect this baby?"


The clank and moan of chains knocking against tetherball poles provides a lonely soundtrack for the empty playground at Yakima's Hoover Elementary. Near a sign that urges kids to "Read More this Summer," the monkeybars emerge from bare dirt. Pink ribbon flutters around exposed sprinkler heads, and off to the side of a soccer goal sits a two-story mountain of dirt covered with black plastic and sandbags. In the soil underneath the tarp are levels of arsenic nearly four times Washington's threshold for requiring cleanup; there's lead there, too, at nearly three times the threshold.

Over the past five years, Washington's Department of Ecology has overseen remediation of 20 out of the 35 schools in the central part of the state where lead and arsenic levels exceed state cleanup standards. Here, construction crews are removing 1,135 tonnes (1,029 metric tonnes) of soil to be taken to a local landfill. By the time school resumes this fall, they will have put a barricade of geotextile fabric on the bare ground and capped it with clean dirt and grass sod. The price tag for just this one school: $239,000.

"That's an expensive lawn," says Mark Dunbar of the state's Department of Ecology as he picks up a long-buried white-and-blue marble from the denuded playground, reminding me to wash my hands after I touch it. "But what's the cost of just one cancer treatment these days? It's cheap insurance compared to that."

Even here, though, the scope of inquiry is limited. The Ecology Department decided to test only for lead and arsenic in schoolyards, rather than DDT and other legacy pesticides, because it's cheaper and because the agency didn't want to overwhelm the public, says Valerie Bound, the agency's regional section manager for toxic cleanup.

"When you know it's an old orchard, how far do you want to open the door? Once you have the lab results, you can't really ignore them," says Bound. "The scope of the problem is so large. You can't really clean everything up. You just have to prioritize."

The tests are expensive - $100 to screen for a suite of pesticides and $20 per heavy metal, such as lead or arsenic. The cost underscores how difficult it is for homeowners to discover what might be lurking in their soil, since doing so requires separate tests of multiple samples from different places around their yards.

A composite of five soil samples taken from the Comptons' yard by High Country News revealed levels of DDE, a DDT breakdown product, at 0.6 parts per million - roughly half of the EPA's cancer risk threshold - and arsenic at 4.7 ppm, seven times the safe level in Washington and 67 times the levels recommended by California's environmental health agency. This is fairly normal in central Washington, where background levels of naturally-occurring arsenic are five ppm. Still, that's not much consolation for a pregnant mother. And because the samples taken were combined and tested as one owing to the cost, the pesticide levels are only an average of the sampled sites. So now the Comptons have new questions: are there hotspots in their yard where pesticides exceed safe levels, perhaps due to a spill or an old storage area? Or is most of the yard relatively clean?

"This is worrisome," says Compton, after she receives the test results; it's late summer, and she and her son have been digging in the dirt for days. Even though the test came back within a zone deemed safe by government experts, she worries that future standards will be much stricter. Already California has set levels that are far more protective, based on the most recent research. So Compton has decided to be proactive, within reason. The only failsafe solution - removing the topsoil - runs a prohibitive $950,000 an acre. Instead, next spring Compton will build raised garden beds, line them with an impermeable barrier and fill them with clean soil.

Set against the onslaught of toxic chemicals in our world, legacy pesticides are just another problem to contend with. Possible threats lurk everywhere, from the kitchen-sink cabinet filled with household cleaners to the flame retardant-impregnated mattresses in the bedrooms. "I can't live my life completely freaked out about these things," Compton says. "You can only protect your kids, and yourself for that matter, from so much. You're always going to be living with a certain amount of uncertainty."

Even so, the urge to protect is strong. On a warm summer night, Compton and 13 other moms hover around a picnic table at Yakima's Franklin Park. It's piled high with baking soda, apple cider vinegar and vegetable glycerin.

"I know we all want to do something, to take action," Suzanne Noble, a local special-ed teacher, tells the small group, which meets monthly to discuss how to reduce their kids' exposure to toxic chemicals. Today's lesson, taught by Noble, is on how to make your own cleaning products.

Children bounce in and out of their mother's laps, distracted by the Fisher-Price toys scattered on the ground. Two little girls race each other across the grass, their hair flying in their eyes. They stop at the finish line - a pine tree - and roll down a slight incline, holding their bodies as straight as Tootsie Pops. At the bottom of the hill, one of them wipes her face, smearing mud and snot, and laughs into the evening.


Rebecca Clarren is a freelance writer for High Country News and lives in Portland, Oregon.