At home, the diligent rinsing of produce can feel like an obsessive ritual — but we’re accomplishing less than we hope with our scrubbing and produce-detergents. Frighteningly, many new pesticides can’t be washed (or peeled) off, because they’re actually grown into the flesh of the plant. They’re “systemic.”
What are systemic pesticides? Unlike the old-style non-water-soluble sprays, which tend to stay put on the plant’s surface after application, systemic pesticides are absorbed into the plant’s tissue, usually via the roots. They are highly water soluble, which means that a plant simply drinks up the pesticide-laden water, and the chemical is transported through the plant’s vascular system. If a bug attempts to nibble any part of this plant, it will soon die.
In many food plants, the thirstiest part is the fruit or edible vegetable flesh. This means that when you buy produce treated with a systemic pesticide, all that juicy, crispy, pulpy, or leafy flesh carries the chemical residue. The pesticide is present throughout, and cannot be removed.
What's the risk?
No one can yet make precise predictions about the long-term health effects of routine pesticide exposure through food, but the data suggest reason for caution. The Environmental Protection Agency (EPA) regulates pesticides and has the power to ban products which show clear harm to humans or the environment, but their approach tends to hold each chemical “innocent until proven guilty”. In contrast, European regulatory agencies tend to err more on the side of caution in protecting public health, and have placed stricter limits on some systemic pesticides in recognition of early findings. The drawbacks of the EPA’s “wait and see” approach are well illustrated by the legacy of DDT. We continue to consume DDT degradants in the majority of American dairy products today, despite DDT’s ban in this country since 1972.
Virtually all of us (99%) test positive for DDT residues in our own bodies. Based on what we know now, most of us would gladly erase DDT from the history books, despite all the flawless-looking fruit it produced. Will our future selves look back on today’s systemic pesticides with the same regret?
GE crops: no need to spray, corn kills pests on contact
Some genetically engineered crops have been “programmed” with a special super-power: they manufacture their own systemic pesticide. Bt-corn already pervades the heavily-corn-dependent US food supply. It is modified with the genes of a soil bacterium to produce an endotoxin which kills the European corn borer. If you ever eat non-organically produced food, at home or in restaurants, you’re probably eating Bt-corn or it’s byproducts, including corn-fed meat and corn-syrup-sweetened products.
In some cases, insects have already grown resistant to the toxins found in the first-generation GE crops; Monsanto quickly responds with a new product, a crop which produces multiple additional toxins. Concerns have been raised about Bt-corn and other similar GE crops, including worries that these crops are threatening biodiversity, causing unexpected health effects in humans, and possibly contributing to Colony Collapse Disorder in honeybees, as well as the demise of monarch butterflies. Thus far, no research has proved sufficiently persuasive to the EPA.
If you wish to avoid GE/GMO foods, buying certified organic whole unprocessed foods is your best bet. Some food processors are opting into a voluntary “Non-GMO” labeling system. In the absence of such information, you can assume a processed product is more likely than not to contain some GE ingredients.
Health effects: what we don't know might hurt us
The National Institute of Environmental Health Sciences says simply: “Scientists do not yet have a clear understanding of the health effects of these pesticide residues.” No one disputes the potentially-fatal consequences of higher-level exposure — news reports confirm poisonings of farm workers and give rise to grave concerns for those who live and work near conventional farming operations.
No one disputes that small children and pregnant women are particularly vulnerable to even low levels of pesticides. Many of those chemical compounds cross the placenta to directly enter the fetal bloodstream: in this formative stage of development, the stage is set as pregnancy is a great time to make clean organic produce the foundation of your diet, and to minimize exposure to all types of pollution; prenatal pollution exposure has been linked to many later problems, including autism.
Regarding systemic pesticides specifically, many are still so new that there hasn’t been time for long-term human studies. One of their selling points: they are designed to be less toxic to mammals. The compounds break down in about 35-42 days, rather than persisting in the soil. The methods of application — seed treatment or dispersal in irrigation water — pose less immediate threat to field workers. The most popular, imidacloprid, is listed as posing “minimal carcinogenic risk” after a 2 year study on rats, however the substance did cause thyroid damage in rats. At this early point, the human-health dangers seem milder than the potential ecological effects. Ultimately, our fates are inextricably bound up with the fates of all the tiny bugs in the cornfield.
Environmental impact: playing with disaster
By some reckoning, systemic pesticides could protect an ecosystem by reducing the need for spraying. Large-scale crop-spraying can cause unwanted exposure to wildlife and water systems, as well as farm workers and those living nearby, who are subject to greatly increased risk of acute pesticide poisoning. The pro-systemic pesticide argument holds that it must be a good thing to have the pesticide absorbed by the target plant, rather than randomly dispersed in the air. Unfortunately, the water-solubility of these compounds also means it’s even easier for rain or irrigation to wash the chemical into a nearby stream or seep through the soil into groundwater reserves.
So much about how systemic pesticides are ultimately dispersed through the food chain remains unknown. Studies are in progress, but meanwhile these products are applied on a huge scale by massive farm operations across the nation. Birds have been observed retching and with impaired coordination after eating treated seeds. But ultimately, species such as birds and fish may suffer more from food chain disruption, as it is the smallest species which are most devastated by contact with systemic pesticides via dust, plant matter, and water.
Neonicotinoids: biting the hand that feeds us?
One popular category of systemic pesticides has received special attention in the past ten years. The relatively new neonicotinoid “family” includes the most widely used insecticide in the world, imidacloprid. About 95% of US-grown corn and canola is treated with neonicotinoids, as are the vast majority of vegetables and fruits.
Many of these crops are dependent upon pollination, such as tree fruits (apples, cherries, peaches, etc.). Neonicotinoids are highly effective at killing target insects, such as aphids — hence their popularity. Initially, these pesticides were thought to leave pollinators and other beneficial insects unharmed; later research found a different story. Even with tiny exposure via contaminated pollen, nectar, or dust, bees appear disoriented and uncoordinated, and may become vulnerable to pathogens due to immune disruption.
In addition, the presence of neonicotinoids — even at allowable levels — appears to reduce water-dwelling invertebrates by 50%. This has obvious repercussions up the food chain, impacting birds and other wildlife that depend on aquatic insects as food. Current research is calling urgently for a safe alternative to neonicotinoids; yet thus far, the industry appears reluctant to let go of such a successful product.
Over half of managed honeybee colonies in the US have been lost over the past 10 years, since Colony Collapse Disorder was identified. Without pollinators, our food supply would suffer unimaginable deficits, as most fruits, nuts, and luxuries such as chocolate and coffee would become impossible to produce. Even staples such as potatoes are pollinator-dependent, and yet the US has been reluctant to invest sufficient money and energy in research and proactive solutions. You can get involved in the movement to support the health of pollinating insects — after all, they support our health every day. At home, make sure your backyard is a safe haven for beneficial bugs by avoiding toxic garden products and including as many bee-friendly plants as possible.
Know your food: educate yourself
The Pesticide Action Network has a helpful consumer-information website called What’s On My Food?. You can search for most fruits and vegetables, meats, milk, and even drinking water to find the average levels of pesticides for that particular product. Results will list various pesticides found, along with icons showing their known and suspected risks, including human carcinogens, hormone disrupters, and honeybee toxins. Helpfully, this site also shows the difference between conventional and organic produce for each item.
Another great resource, now familiar to many, is the Environmental Working Group’s Dirty Dozen list. The most heavily contaminated produce items top this list of shame. Systemic pesticides often combine with other residual toxins to create a chemical “cocktail” whose impact has never been studied: compounds can combine to create synergistic effects in our bodies (or the bodies of other creatures) but these combined effects are mostly unknown. And although there are limits for the allowable quantities of individual pesticides found in each apple, there are no limits for the mingled total of all pesticides found in that same fruit.
It may feel hopeless, so much unwanted pesticide exposure creeping into our food supply without our consent. But starting in our own backyard, we can learn about healthy alternatives to toxic pest control and share these tips with our friends and neighbors. Growing your own food is a life-affirming act of caring for our families and our world by contributing wholesome, pesticide-free vegetables and fruits.
Another growing movement is buying food locally: know your farmer, ask questions, get answers, and thank them for the work they do. The lettuce may cost a little more, but it’s fresher and cleaner — and rest assured, your farmer is not getting rich! Our food supply is a fragile web, but we can all do our part to strengthen its fibers by voting with our wallets. The alternative: that uneasy feeling every time you bite into an industrial peach. The bugs and bees aren’t given a choice — let’s use ours.