Neonics On Tap: Farm Pesticides in Drinking Water

While the University of Iowa has been aware of this situation since last summer, news of a municipal water supply found tainted with neonicotinoids just broke last week. That’s right, dangerous farm pesticides in drinking water supplied to homes and business in Iowa City.

Though neonicotinoids have been on the US market since 1991 when Bayer CropScience introduced imidacloprid (and licensed in Europe in 1994), this is the first discovery of its having entered a city water system. But should we really be that surprised? Waterways and surface water near in agricultural areas have tested positive for neonics for some years. Reports of contamination through filtering into ground water and runoff date back to at least 2003. So, the surprise should be that news of these farm pesticides in drinking water took so long. And the University of Iowa tested treated water in the city water supply. But then again, until this 2016 study, no one was testing our water supply for neonic pesticides. Why?

No EPA standards for neonics in drinking water exist.

Why are there no regulations for neonics in the water supply? The excuse: these chemicals are too new, and way too under-studied for human toxicity. Twenty five years and many environmental and wildlife studies under its belt does not a new chemical make. Besides, a peer-reviewed paper published in the Journal of Environmental Immunology and Toxicology reported multiple studies that found it attacks the immune system of vertebrates, including mammals – which we humans happen to be. Neonics, it says are a compound with sublethal toxic effects, or they’re the precursor to the cause of fatality. It was written in 2012, but not published until 2014.

The study found 3 different neonics – imidacloprid, clothianidin, and thiamethoxam – in University of Iowa drinking water samples taken from May through July of 2016. Initially, the researchers were simply curious if they would find this particular family of farm pesticides in drinking water at the height of the planting and spraying season in the surrounding area. And when it those tested positive, they took samples from other water management facilities in Iowa City. Affirmative there too. Those three neonics showed up in a range of levels from 0.24-57.3 nanograms per liter.

The Washington Post, referencing University of Iowa environment engineer Gregory LeFevre on April 5th, reporting the amounts detected were very tiny – as in parts per trillion. Yet, the difficulty in removing neonic class chemicals is cause for concern. Most water filtering systems do not remove pesticides, and these “polar chemicals” flow right though sand filters. Activated carbon filters proved more effective, but not totally.

However, according to an article by George Monbiot in The Guardian (August 2013) it only takes 5 nanograms of neonictotinoids to kill half the bees exposed, and that…

by volume these poisons are 10,000 times as powerful as DDT.

The journal paper by Dave Goulsen (University of Stirling) that Monbiot links to reports that the crop plants only take up 1.6-20% of systemic seed dressing, while 90% or more of the remaining active ingredient enters the soil and persists there for up to 19 years (soil type dependent). Less than 2% of the coating is lost in powder drift – but where it lands, it too dissolves readily in water, and remains on the soil surface until wind or precipitation move it elsewhere. And Goulsen states that before becoming bound to soil neonics “readily leach, predictably placing significant levels in groundwater and runoff” when heavy rainfall occurs.

Farm pesticides in drinking water attack your nerve system too.

Last week on April 5th The Daily Mail reported that scientists find these dangerous farm pesticides attack human nervous system cells – and that neonics “have been spotted in taps across the US.” (A hot tip?) The article goes on to say that past research suggests humans suffer developmental or neurological problems from chronic exposure.

Interviewing the lead UI author and graduate fellow Kathryn Klarich, The Daily Iowan reported on April 11 that toxicity evaluation was not part of this research. It doesn’t appear to be part of the bulk of any studies on the real dangers of these widespread and heavily used pesticides either:

There are not good data on low-level chronic exposure [of humans to neonics], so we can’t make a conclusive statement on whether they would be toxic,” Klarich said. “They’re not known to be really toxic to humans except in really high concentrations, which wouldn’t be present in drinking water.

And what about the water safety in millions of wells that supply rural homes and businesses? Many wells only have screen filters to keep sand out of pipes. Some people have water softeners or inline filters to eliminate mineral content, but nothing as sophisticated as a city water facility. How much is in that glass full of H2O straight out of the ground is up to the homeowner to discover. And it’s not a normal water test, so isn’t likely available at the average local water testing place.

But… only 8 studies have been conducted on how they affect human health. Three studies on neonic poisoning reported 2 deaths in 1280 cases, and the methodology used in chronic exposure testing resulted in weak findings. A review published in the Environmental Health Perspectives journal in April 2017 gives the details on these studies to date, concluding it’s high time for serious human safety testing.

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Image courtesy of batil.

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