Summertime Blues: Pesticide-Laden Strawberries And Your Health

Pesticide spraying at a farm on the North Shore of Massachusetts. (Photo: Alexandra Morris)

Pesticide spraying at a farm on the North Shore of Massachusetts. (Photo: Alexandra Morris)

By Alexandra Morris

This weekend marks the start of the summer season, but I can’t help dwelling on the downside. Each year at this time, crowds from urban Boston descend on the farm next to my parents’ house on the North Shore in Mass. to pick their own strawberries – fresh, sweet, ripe…and coated with toxins.

While the farm staff warns visitors to wash the fruit before eating it, many choose to snack along the way (one group was caught sitting in the strawberry field with a can of “Reddi-Whip” in hand). After all, what’s the cost of a few unwashed strawberries?

Unfortunately, when it comes to our health, the cost may be fairly high.

Over the years, researchers have documented the bad effects of pesticide exposure on human health. Recently, though, and at a forum this week at Harvard, there’s been increased attention on the links between pesticides and neurodegenerative diseases, notably Parkinson’s and Alzheimer’s.

In a study published earlier this year in the journal Neurology, researchers from UCLA identified the way in which certain pesticides can increase the risk of Parkinson’s disease. They also found that people with a common genetic variant are even more sensitive to these pesticides – they are two to five times more likely to develop Parkinson’s if exposed.

“Once you identify the toxicity of these things, getting rid of the bad pesticides…would be a goal, not just for the people that live in the area, but for the workers that use it,” said the study’s lead author, Dr. Jeff Bronstein, a professor of neurology at UCLA.

In a separate report out of Rutgers University, published in JAMA Neurology, researchers found that exposure to the pesticide DDT may increase the risk of developing Alzheimer’s disease. In the study, researchers found that levels of DDE, the chemical compound that develops when DDT breaks down, were higher in the blood of Alzheimer’s patients compared to those without the disease.

And the effects go beyond the risk of Parkinson’s and Alzheimer’s. Marc Weisskopf, an associate professor of environmental and occupational epidemiology at the Harvard School of Public Health, who spoke at the Harvard forum, said there is evidence that pesticides contribute to a host of neurodevelopmental disorders as well, from ADHD and developmental disorders to lowered cognitive performance. At high levels of exposure, we know it’s a problem, Weisskopf said. But the tricky part is understanding the effects of low-level exposure.

(Sharon Mollerus/flickr)

(Sharon Mollerus/flickr)

Although DDT has been banned in the U.S. since 1972, more than 75% of the population in the U.S. has traces of the chemical in their blood. DDT can take decades to break down in the environment. People are also exposed when they consume foods from areas of the world where DDT is still being used such as areas in Africa and southeast Asia.

DDT is an extremely effective insecticide and is used to combat malaria and other vector-borne illnesses in some parts of the world, where scientists and health experts must weigh the looming threat of malaria against a more distant risk of developing a neurodegenerative disease.

Pesticides, clearly, can also play an important role in agriculture production. Dr. Jason Richardson, lead author of the Rutgers study and an associate Professor at the Rutgers Robert Wood Johnson Medical School, grew up on a farm and knows first hand the importance of using pesticides to protect the crops. “In reality, for us to produce the amount of food that we need to feed our country…pesticides are pretty much a necessary evil,” he said. “What we can do is take better precautions and learn more about what these potential effects are.”

From March to November, the farmer next to my parents – let’s call him Farmer Brown for the sake of anonymity – sprays his fields. Once the pesticides (which include insecticides, herbicides, and fungicides) are airborne, they can leak over onto neighboring properties – an effect known as “pesticide drift.” Farmer Brown is a friend of my parents, but their philosophies on land stewardship differ entirely.

It’s an issue that has pitted neighbor against neighbor.

For my parents, both conservation biologists, one of their main concerns with pesticide drift is the impact on the bees and butterflies that pollinate their gardens and serve as a food source for bluebirds, swallows, and other birds in the area. But as their daughter, I worry about the effect of the toxic air they’re breathing on their own health.

“We have tried not to allow the pesticide issue to affect our friendship with our neighbor,” said my mother. “We both know how important open space and agriculture is to our future in New England.”

“We need to get agricultural interests and environmental interests on the same side,” said my father. “These poorly conceived practices are allowed by current law and regulation. That is not our neighbor’s fault.”

Importantly, it’s not only farmers that are spraying pesticides. Homeowners use up to 10 times more pesticides (including chemicals like Roundup, but that’s another story) per acre on their lawns than farmers use on crops, according to the U.S. Fish and Wildlife Service.

Proving there is a direct link between pesticide use and health outcomes is inherently difficult – it requires long-term studies that can be complicated by many other factors. But for some researchers, despite the limited data, the connections between pesticides and poor health outcomes are pretty clear.

“In general, the biological plausibility points in that direction,” said Alex Lu, an associate professor of Environmental Exposure Biology at the Harvard School of Public Health. “If this is how we kill insects by paralyzing their neurological system, most likely it will happen in humans.” It won’t kill humans, he went on to say, but it could produce neurological effects.

It’s not just human health we should be worrying about. Lu is the author of a study published this month in the Bulletin of Insectology on the effects of pesticides on bee colony collapse disorder. His team found that the use of two neonicotinoids – a widely used form of insecticide – led honeybees to abandon their hives during the winter months and eventually die.

“More than one-third of the food that we commonly eat needs pollination,” said Lu. “Those foods, including fruits and vegetables, are nutritious foods that we definitely need…Not having enough bees to pollinate those crops will cause a lot of agricultural revenue loss.” In other words, the same pesticides that are being sprayed to help the crops may indirectly cause their demise.

Bayer – the company that manufactures the neonicotinoids that were tested – questioned Lu’s research, saying that his team used dosages of pesticides that were 10 times greater than what bees might face in the wild, according to coverage in The New York Times.

And indeed, Lu says this this type of research can be challenging – in part because there is no “control” population. Everyone is exposed to pesticides to some degree, so it’s hard to compare people, he said during yesterday’s Harvard forum on pesticides and food. Another issue is the lag time between exposure to the diagnosis of the disease – it’s difficult to know whether it was the pesticides or another factor that caused the illness.

To address these concerns, researchers compare populations that are at increased risk of exposure – such as agricultural workers or families that live in close proximity to farms – to those that have less of a risk of being exposed.

But the problem these days isn’t just protecting the crops from insects and other potential infestations. “People buy with their eyes,” said Farmer Brown. They want that flawless strawberry or apple. In addition to regulating the use of the more toxic chemicals, perhaps we need to adjust our expectations of the food we eat – pretty doesn’t necessarily mean good.

So what’s a consumer to do?

Each year, the Environmental Working Group publishes the “dirty dozen” and the “clean fifteen” lists – two ratings of conventional foods with the most and least pesticide residue. Since many consumers in the U.S. can’t afford to purchase only organic produce, researchers at the Harvard forum advised consumers to look to these lists to help guide their purchasing choices. For example, a consumer could purchase organic apples and strawberries – two items on the “dirty dozen” list, and conventional avocados and asparagus – two items on the “clean fifteen.”

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  • Donald Sutherland

    As an organic farmer my wife and I have noticed a serious absence of pollinators in the field.
    Here is my story on those observations:

    • Lawrence

      Donald we need more farmers like you. And yes, it’s sad.

  • Ryan Cahill

    Three things I wish you would clarify:
    1) are consumers good-to-go with organic… don’t need to worry about pesticides at all?
    2) what is the best way to rid your fruits/veggies of pesticides…soap wash?
    3) why are farmers allowed to sell food with toxins on them? They should be considered an ingredient in the food.

    • Lawrence

      Farmers are allowed to use them because the FDA is made up of lawyers that also work for the chemical corps.

      PS And you are footing the bill for their salaries. ( Just to poison us)

  • Mark

    If the author’s parents’ neighbor sprays his land from March to November, then no amount of washing the fruit is going to help. The chemicals are in the soil, and then inside the fruit that grows from it.

    There are no-spray farms out there, if people would care to look for them. But, pesticide spraying surely is a necessary evil. This is such a frustrating topic.

  • Lawrence

    One of the most newsworthy articles about a long standing problem that few realize. Thanks for bringing this highly important topic up especially during this season.

    What angers me the most is that this is not new. How these dangerous chemicals are approved to get into our food supply is beyond me.

    Let’s not forget environmental activist Rachael Carson from Maine who witnessed the “Silent Spring” where there were no birds chirping due to pesticide use, and that was in the 50s! She influenced JFK to create the EPA and it’s a shame that we still have this problem that is likely to increase all of these diseases.

    It’s also a shame that her documentary is largely unknown yet the world is able to recite every line from Spiderman,

    Her documentary is in libraries:

  • Jim McCauley

    We see article after article warning us about the dangers of pesticides. Despite this, the Massachusetts Department of Agriculture Resources routinely rubber-stamps NSTAR’s request to spray pesticides throughout Cape Cod. Does MDAR deserve the right to have sole responsibility over regulating pesticides or should local communities have the right to act on their own? Every town on Cape Cod has objected to the spraying. Shouldn’t towns have the right to protect their own environment, considering that MDAR appears stuck in another time zone?

    • Lawrence

      If our society were more interested in avoiding these toxic chemicals that are harming our health, we should be making calls, forming groups and takinging a stance. As it is, we are on FB for hours making needless comments on cat videos and which celebrities have aged the worst.

      Rachael Carson was a pioneer in the 50s, she pushed, was threatened but now we are so passive, uninformed and lazy that no one does anything. The chemical companies who buy influence can do what they want.

      • pennyroyal

        Why target those who watch cat videos? There are millions of ways we can divert our attention away from the hard issues. Denial is easy and it gets easier, turn the page, watch an escapist program on TV, delete a message.

        How then do we light a fire under people? The “On Point” interview yesterday with Doris Kerns Godwin had the author speaking of Teddy Roosevelt (subject of her new book) on how TR managed to engage and empower the general public to sustained action.

        I don’t think we are so much lazy, though that may be, as scared–and overwhelmed. When we ask who can lead this country out of the stuckness and passivity it’s in, we see cynical politicians in thrall to corporations, certain religious groups, business interests, etc. etc. (You know the litany). And both parties (though not equally) need to be held accountable. But I don’t see any ready answers.

        • Lawrence


          Cat videos are just an example. Celebrity gossip, once the domain of the biggest joke newspaper, ( National Enquirer) is now the biggest news trending on social media and even national “news”.

          • pennyroyal

            sometimes I need the cat videos to remind me of how humane people can be and to get my blood pressure down after reading articles like this one.

  • Richard Knox

    Level-headed discussion of a complicated and fraught subject. Thanx, Alexandra.