Neonic Use Said Dramatically Increasing in US Midwest

31.07.2014 -

Neonicotinoids (neonics), the pesticides temporarily banned in Europe in crops attractive to bees, have been found commonly in streams throughout the US Midwest, according to a new report by the US Geological Survey (USGS).

The USGS research is the first broad-scale investigation of neonicotinoid insecticides in the Midwestern US and one of the first conducted in the country.

According to the research team, the use of neonicotinoid insecticides has dramatically increased over the past decade, particularly in the Midwest, where the states of Iowa, Minnesota, Montana, Nebraska, North Dakota, South Dakota, and Wisconsin have the highest rates of use. The use of clothianidin - one of the chemicals the pesticides commonly contains - on corn has almost doubled in Iowa alone between 2011 and 2013, USGS added.

"Neonicotinoid insecticides are receiving increased attention by scientists as we explore the possible links between pesticides, nutrition, infectious disease and other stress factors in the environment possibly associated with honeybee die-offs." said Kathryn Kuivila, the team leader.

Of the three chemicals most often found in a USGS analysis of 79 water samples taken from nine rivers, clothianidin was the most commonly detected. It showed up in 75% of the sites and at the highest concentration. Thiamethoxam was found at 47% of the sites and imidacloprid at 23 %. Two chemicals, acetamiprid and dinotefuran, were only found once, and the sixth, thiacloprid, was never detected. These states have the highest use of neonicotinoid insecticides, mostly from treated seeds.

While Croplife America, an organization representing the agrochemicals industry, maintains that the precise application of the active ingredient minimizes risks, USGS said pesticides taken up by plants through seed treatments don't stay in the plants. What's more, neonics are highly water soluble and break down in water more slowly than the pesticides they've replaced.

In its ongoing research, the US Environmental Protection Agency has classified all detected neonicotinoids as not likely to be carcinogenic to humans. Some are said to be toxic to aquatic organisms if they are exposed for an extended period.

In 2012, a USGS research review on fungicides and their effect on waterways, although noting numerous data gaps, said it had found evidence of "significant sub-lethal effects of fungicides on fish, aquatic invertebrates, and ecosystems."