In a recently released study, the U.S. Geologic Survey (USGS) announced that neonicotinoid pesticides are still present in tap water, even after being treated in water management plants.
Neonicotinoids are among the most widely used class of pesticides in the world, and are known to be a potent neurotoxin. Though they are considered more of a harm to insects (rather than vertebrates) in the short-term, the effects of chronic exposure have not been extensively studied. A few projects have tied some neonicotinoids to development and neurological concerns, as well as inflammation of the liver and central nervous system, but there have been no attempts to curtail use. Some of the most incriminating evidence against neonicotinoids is their speculated role in declining pollinator populations; other research has also accused neonicotinoids of harming non-target species in aquatic ecosystems.
As evidenced by the harmful consequences for ecosystems and environment, part of the problem with neonicotinoids is their prevalence (they are especially common in surface waters), and their persistence in the environment. According to the USGS study, “at least one neonicotinoid compound was detected in 63% of the 48 streams measured.”
Moreover, as the USGS study demonstrated, treatment systems do not have the means of effectively removing neonicotinoids from water. The USGS reported “conventional water treatment results in no measurable removal” of two specific types of neonicotinoids.
While the USGS study was limited to the area surrounding the University of Iowa, the scientists noted that neonicotinoids were “likely present in other drinking water systems across the United States,” due to their widespread use. The researchers also cautioned that their XX did not even produce the full picture; one type of neonicotinoids has been show to react with chlorine and “may undergo at least partial transformation during chlorination”– meaning the neonicotinoids may, during water treatment, be transformed into other toxic compounds, or may produce toxic byproducts.
Fortunately, the researchers did have good news to buffer their alarming results. Their study measured the efficacy of granular activated carbon (GAC) and found it “rapidly and nearly completely removed all three neonicotinoids” they were studying. The presence of pesticides is mostly a concern in highly agricultural areas, like the Midwest, and the scientists recommended investing in GAC filtration in those areas, as GAC is far more economical than reverse osmosis or advanced oxidation processes filtration systems.
Concerned for your own home? Check out Minnesota Department of Health’s guide to at-home GAC filtration.