The Choice Is Clear on Pesticides

Erika Schreder has worked for the Washington Toxics Coalition as a staff scientist since 1997. She has a Master’s Degree in resource ecology and management and a B.S. in molecular biology. She currently directs the Clean Water for Salmon campaign, which aims to end pesticide uses that pollute water and threaten salmon.

Editor’s Note: Whatcom Watch will publish most of the 64-page report “Pollution in People” released May 2006 by the Toxic-Free Legacy Coalition. The entire report is available as a pdf file at http://www.pollutioninpeople.org.

Part 6

Over 15 years as a community organizer and toxic chemicals policy expert, Laurie Valeriano has learned a thing or two about avoiding products that could harm her health. You won’t find vinyl shower curtains or toys at her house, and she limits her use of personal-care products that could contain toxic additives such as phthalates. She knows which plastics are relatively safe, and which ones to steer clear of.

This knowledge, unfortunately, has not fully protected Laurie or her family. Laurie’s body contains mercury, PFCs, toxic flame retardants, PCBs and phthalates, albeit at lower levels than in other participants. Moreover, it is likely that she passed significant amounts of these chemicals to her three children in the womb and while breastfeeding.

But what we did not find in Laurie’s body shows that her choices are — in at least one significant way — having a positive effect on her and her family’s health. The Pollution in People study, which tested for metabolites of commonly used pesticides such as malathion, chlorpyrifos, azinphos methyl and carbaryl, did not find any sign of pesticides in Laurie. Why? Well, for starters, Laurie and her family use alternatives to pesticides in their home and garden, go to a pesticide-free park and eat organically grown food. Her decisions are backed by good evidence, too: University of Washington research has found that children who eat an organic diet are much less likely to be exposed to pesticides (Lu 2005).

Senate Majority Leader Lisa Brown (D-Spokane) has made different choices. While she’s been a long-time advocate for government action to protect people and wildlife from toxic chemicals, she makes consumer decisions that most any well-educated woman in the United States would: her home includes electronics likely embedded with toxic flame retardants, and she drives a car with an interior made with phthalates. Most of the food she and her son eat is conventionally grown, not organic. And Lisa, along with five other participants, tested positive for pesticides.

We tested for a series of pesticide breakdown products, or metabolites, that indicate exposure to organophosphate pesticides, as well as the metabolite of the insecticide carbaryl. The carbaryl metabolite was most commonly found, turning up in five participants.1 We also found the organophosphate metabolites known as DMTP (in four participants) and DMP (in two), indicating exposure to the widely used insecticides azinphos methyl and malathion, among other pesticides.2 These insecticides are very commonly used in agriculture, and malathion is also found in some home-use products. One participant had the metabolite DEP, suggesting she had been exposed to the organophosphates diazinon or chlorpyrifos, or other less commonly used pesticides.

We also tested for a metabolite specific to chlorpyrifos exposure but did not find it in any study participants, possibly reflecting the phaseout of this pesticide’s residential uses, which began in 2000.3 However, pesticide levels in two of our participants, Deb Abrahamson and Ann Holmes Redding, suggest that the two are more highly exposed to organophosphate pesticides than 90 percent of people nationally when compared against the results of a 2005 Centers for Disease Control and Prevention study (CDC 2005). Deb had levels of DMP, DMTP and DEP that put her in the top 10 percent nationally; Ann’s levels of DMP and DMTP were also in the top 10 percent. Organophosphates do not persist in the body, so these levels reflect recent exposures. Many of us are exposed to these pesticides regularly over our lifetimes, which often leads to consistently detectable levels.

The chart on the facing page shows participants’ exposures to organophosphates and carbaryl. The chart shows the number of metabolites of these pesticides detected, out of a total of seven tested.

Most of our 10 participants don’t spray these insecticides in their homes or gardens, so the most likely source of the pesticides in their bodies is their food, especially since most of their diets are not organic. The organophosphate pesticides diazinon and chlorpyrifos, once the most widely used insecticides in U.S. homes and gardens, are now primarily used in agriculture (with a few exceptions, they are not used in urban areas).

Azinphos methyl is highly acutely toxic and is used only in agriculture, on such crops as apples, cherries and pears (USEPA 1999). Malathion is used in both settings, but most commonly in agriculture. Carbaryl is sprayed on about half of Washington’s apple crop and much of its grape acreage (WSDA 2003).

The U.S. Department of Agriculture (USDA) conducts a yearly “market basket” survey to test for residues of pesticides in produce. The most contaminated fruits and vegetables include apples, bell peppers, celery, cherries, grapes, nectarines, peaches, pears, potatoes, raspberries, spinach and strawberries. Purchasing some foods in particular comes with a near-guarantee of pesticides along for the ride. USDA’s most recent testing found that 98 percent of apples and 97 percent of bell peppers are contaminated (USDA 2006). All of the apples and pears tested by the USDA were contaminated with 1-napthol, the breakdown product of carbaryl. The agency found up to nine pesticides on a single apple and eight in a single grape sample.

We found evidence in our study that suggests eating organic provides some protection from pesticide exposure. We tested for a correlation between pesticide detections in our participants and the number of organic meals each person reported eating. We found a statistically significant correlation, indicating that the more organic food each participant ate, the less likely he or she was to have pesticides in his or her body.4

Farm workers and farm worker families are exposed by far to the most agricultural pesticides. While mixing and applying pesticides, they come into contact with significant amounts of chemicals, later tracking them into their homes on their shoes and clothing. Their homes, which are often near the farms they work on, become further contaminated when pesticides drift from nearby fields.

It’s no secret that these pesticides can harm the nervous system. Organophosphate pesticides block an enzyme, acetylcholinesterase, which is critical for proper transmission of signals from one nerve to the next. Shortly after being exposed to a high dose of organophosphates, a person will suffer weakness, cramps, breathing trouble, nausea and vomiting (USEPA 1999).

Worse, some effects may persist long after exposure. In one study, farm and pest-control workers tested months to years after a pesticide poisoning incident had poorer memory and damaged motor skills, as well as anxiety, depression and confusion (Eskenazi 1999). Carbaryl has similar immediate effects on the nervous system. Inhaling or ingesting large amounts can cause nausea, stomach cramps, and diarrhea, as well as sweating, blurred vision, loss of coordination and convulsions (USEPA 2003).

Increasing evidence from animal studies also indicates that the brain development of fetuses and children may be impaired by exposure to organophosphates. Studies in young mice found that a single dose of an organophosphate caused permanent damage to brain function, including hyperactivity (Ahlbom 1995). Similarly, mice with prenatal exposure to diazinon had poorer coordination and endurance, as well as delayed sexual development (Schettler 2000). Rats with prenatal exposure to chlorpyrifos had smaller brain weights and decreased reflexes (Chanda 1996, Schettler 2000).

Recent studies in farm worker populations indicate that developmental damage from these pesticides is occurring in people. University of California researchers have studied a group of children born to farm workers in California’s Salinas Valley, where 500,000 pounds of organophosphate pesticides are used each year. In a 2005 study, the group reported that infants with greater exposure to organophosphates had more abnormal reflexes (Young 2005). They also found that mothers with higher exposures are at increased risk for preterm birth (Eskenazi 2004).

In Oregon, researchers compared neurological performance of farm workers with that of an immigrant community living on the coast with little exposure to pesticides (Rothlein 2006). Their findings: adults with greater exposures to organophosphates scored more poorly in tests of attention spans and motor function.

There’s also powerful evidence that carbaryl may cause cancer; EPA considers carbaryl a likely human carcinogen (USEPA 2003). Several studies have reported greater incidence of childhood brain cancer in homes using carbaryl (Davis 1993) or types of products that may contain carbaryl (Pagoda 1997). Other studies have found an elevated risk of non-Hodgkins lymphoma (NHL) among farmers who handled carbamate insecticides in general and carbaryl in particular.

A study of Canadian farmers showed that those using carbaryl had twice the incidence of NHL (McDuffie 2001). A reanalysis of pooled data from three separate studies in several Midwestern states found a 60 percent increase in NHL among farmers who reported using carbaryl (Zheng 2001). While these studies don’t prove an association, their sample sizes were large and their findings correlate with evidence from animal studies linking carbaryl to immune suppression, a known risk factor for NHL.

The presence of these pesticides in our participants’ bodies demonstrates the extreme flaws in today’s system for regulating pesticides. People cannot fulfill the most basic of needs — nutrition — without risking harm from pesticides that can damage brain function and cause cancer. Although the EPA requires manufacturers to test pesticides for harmful effects, national rules do not prevent continued use of pesticides that test positive for cancer or harm to brain development.

The federal pesticide law — the Federal Insecticide, Fungicide and Rodenticide Act — makes no guarantee that pesticides allowed for use will not cause harm to people and other living things. Rather, the law protects a pesticide’s uses unless the chemical poses “unreasonable risk to man or the environment, taking into account the economic, social and environmental costs and benefits of the use of any pesticide.” That is, as long as a pesticide’s perceived economic benefits outweigh its health risks, the law allows for its use.

The Food Quality Protection Act of 1996 aimed to improve this standard somewhat for pesticides used on food, but EPA has yet to implement many of the law’s important provisions. For example, the law requires EPA to consider the cumulative effects of different pesticides that have the same health effect. A decade after its passage, EPA is still in the process of determining how to implement this requirement.

Under the same act, EPA has developed agreements with the pesticide industry to nearly eliminate home use of two important organophosphates, chlorpyrifos and diazinon. As noted above and as demonstrated in our study, however, the widespread agricultural use of organophosphates, including of these two pesticides, means that U.S. residents continue to be regularly exposed to the chemicals.

The EPA has also placed some restrictions on carbaryl, but its use continues in the home and garden setting and in agriculture. And EPA continues to allow other carbamate pesticides, chemical relatives of carbaryl, which have similar effects on the nervous system.

To eliminate exposure to these pesticides, EPA should phase out the use of all organophosphate and carbamate pesticides. The Washington State Department of Agriculture can also take action to phase out these and other toxic pesticides. At the state level, the legislature should continue to provide funding to Washington State University’s Center for Sustaining Agriculture and Natural Resources to develop alternatives for both conventional and organic growers. Cities and counties can eliminate their own use of toxic pesticides on public property, and educate residents about replacing pesticides with healthier practices in the home and garden.

Laurie Valeriano’s family has a pesticide-free park to use because of a community effort to make it one of Seattle’s 22 pesticide-free parks. This effort, together with a campaign led by local residents and organizations, ultimately led the city of Seattle to establish a precedent-setting policy ending its use of the most toxic pesticides, which other cities and counties can emulate.

Next Month: The Chemicals That Came to Stay