[ad_1]
U.S. farmers use smaller amounts of better-targeted pesticides, but these harmed pollinators, aquatic insects and some plants well over decades ago, according to a new study.
Toxicity levels have more than doubled since 2005 for important species including honey bees, mayflies and buttercup flowers, as the country has switched to a new generation of pesticides. But the levels of dangerous chemicals in birds and mammals have plummeted at the same time, according to an article in the journal Science on Thursday.
“The bottom line is that these pesticides, which were once thought to be relatively benign and so ephemeral that they wouldn’t damage ecosystems, are anything but,” said Dr. Lynn Goldman, former deputy administrator of the United States Food and Drug Administration. environmental protection for toxic substances. was not part of the study and is now dean of the George Washington University School of Public Health.
German scientists examined 381 pesticides used in the United States between 1992 and 2016, combining data from the EPA that calculates the effects of toxic doses to eight types of animals and plants with data from the US Geological Survey on the amount of chemicals used each year for dozens of agricultural products. harvests. Scientists have calculated a new measure they call the total applied toxicity for the eight groups of species and trends over time.
“Very often, politicians, the media, scientists only talk about amounts. They always argue ‘OK, the amount of pesticides we use is reduced, so things are getting better’ and that’s not necessarily true, “said lead author Ralf Schulz, professor of environmental science. at the University of Kolenz-Landau. “It is sometimes true, but not always”
The industry continues to develop new pesticides and “very often these new compounds are more toxic,” said Schulz. They include neonicotinoids, which have been linked to one of the many causes of declining honey bee numbers.
The new pesticides are aimed more at animals without a backbone to spare birds and mammals, but that means insects such as pollinators are poisoned, Schulz said.
The same goes for some land plants and for aquatic invertebrates, including dragonflies and mayflies, that birds and mammals eat, he said, adding that future studies should look at the damage in up the food chain.
Chris Novak, president of the pesticide industry group CropLife America, said in an email that “it is essential to note that the study found that large reductions in acute toxicity were achieved in humans and mammals at the same time. in recent decades. “
Novak noted that pesticides are the subject of extensive studies and that “only one in 10,000 finds makes the 11-year journey from the lab to the market.”
It’s no surprise that new generations of pesticides are generally more harmful to insects, which are in massive decline for many reasons, said University of Connecticut entomologist David Wagner, who was not part of the study. But Wagner said the latest research doesn’t provide the data needed to show “pesticides are the main driver of insect decline.”
[ad_2]
Source link