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?"