Nicotine-based insecticides under fire in new studies

Farm Forum

Nicotine-related insecticides widely used on crops are finding their way into the food we eat and the water we drink, two national studies published in the past two months have concluded.

A study released this week by the U.S. Geological Survey found neonicotinoids — a relatively new family of insect-killing chemicals exploding in use in the Farm Belt and a leading suspect in the collapse of bee populations — in nine Midwestern rivers, including the Mississippi and Missouri.

Last month, a study by the Harvard School of Public Health found “neonics” in fruits, vegetables and honey purchased from grocery stores.

The findings come as the Minnesota Department of Agriculture is weighing stronger enforcement of pesticide use, following a push from the Legislature.

The human health effects of neonicotinoids aren’t fully understood, and the Harvard scholars said their findings suggest it’s a pressing question — especially since washing the produce might not remove the chemicals.

A number of studies, including a May study from Harvard, have implicated the chemicals to colony collapse disorder (CCD) among honeybees, the mysterious phenomenon where entire colonies of bees die. Between 2006 and 2011, U.S. beekeepers lost an average of a third of their bees, according to the U.S. Department of Agriculture.

The pesticide industry has disputed such studies. The official position of the USDA’s Agricultural Research Service is that the “cause or causes of CCD have not been identified by researchers.”

Neonicotinoids were introduced about 20 years ago and have been touted by the agricultural and pesticide industry as revolutionary because they treat the plant — often when it’s still an unplanted seed — from within, protecting the plant from leaf-eating bugs, while being less hazardous to mammals than the prior generation of insecticides.

In food

Researchers from the Harvard School of Public health bought fresh fruit and vegetables from grocery stores in Massachusetts and collected pollen from beehives in Massachusetts and New Zealand in 2012. They washed the produce, which included apples, strawberries, peppers, oranges and pumpkins. Seventy-two percent of fruits, 45 percent of vegetables and 50 percent of honey samples contained at least one of several neonicotinoids for which researchers tested.

“These results show the prevalence of low-level neonicotinoid residues in fruits, vegetables, and honey that are readily available in the market for human consumption and in the environment where honeybees forage,” the authors wrote in the study, which was published last month in the Journal of Agricultural and Food Chemistry.

In water

Neonicotinoids don’t just kill leaf-eating crop pests. At least one of the insecticides is known to kill aquatic organisms and several are suspected of being similarly lethal.

Researchers from the U.S. Geological Survey found those toxic concentrations in the nine rivers and streams they studied, which drain most of Iowa and parts of Minnesota, Wisconsin, North and South Dakota, Montana and Nebraska.

“We noticed higher levels of these insecticides after rain storms during crop planting, which is similar to the spring flushing of herbicides that has been documented in Midwestern U.S. rivers and streams,” said USGS scientist Michelle Hladik, lead author of the report, which was published in the scientific journal Environmental Pollution.

CropLife America, which represents American pesticide makers, defends the use of the chemicals and said the USGS study unfairly characterized the neonic levels in the water as potentially toxic.

“The concentrations were well below levels established by the U.S. Environmental Protection Agency to ensure protection of human health and aquatic life,” a CropLife statement reads, in part. “The highest levels detected were at least 40 times lower than benchmarks established by EPA to be protective of aquatic life, and most detections were up to 1,000 times below that level.”

Several Minnesota lobbyists for pesticide companies declined to comment.


Last month, President Barack Obama directed federal environmental regulators to review the effects neonics might be having on pollinators such as bees, as well as dedicate some portions of federal conservation programs to creating healthy pollinator habitats.

Minnesota was already there.

In 2013, lawmakers required any restoration project using state funds to examine pollinator habitats.

At the beginning of this month, a new state pesticide “truth-in-labeling” law went into effect. The law prevents plants treated with neonicotinoids from claiming to be bee-friendly or “beneficial pollinators.”

Meanwhile, state agriculture officials are planning a full review of how they regulate the pesticides. Currently, most pesticide applications require a state license, but the agency doesn’t restrict their uses. Some lawmakers think they should.

“The Ag Department needs to take this new data into account when they register this pesticide,” said state Rep. Rick Hansen, DFL South St. Paul, who sponsored several of the pollinator-related laws. “It doesn’t have to be a total ban. You could ban certain uses and certain applications.”

Hansen and some other lawmakers criticized an early draft of the department’s blueprint for its review, saying it would do little more than seek to raise public awareness. State ag officials declined to comment on July 25, directing a reporter to procedural documents on the department website.