A new study found that American farmers are using a smaller amount of more targeted pesticides, but these pesticides are far more harmful to pollinators, aquatic insects and certain plants than decades ago.
Since 2005, as the country switched to a new generation of pesticides, the level of toxicity to important species (including bees, plum blossoms and hairy cups) has more than doubled. However, according to a paper in the journal Science on Thursday, the levels of dangerous chemicals in birds and mammals have decreased at the same time.
“The most important thing is that these pesticides were once considered relatively benign, and their lifespan was so short that they would not damage the ecosystem, but nothing more,”
German scientists examined 381 pesticides used in the United States from 1992 to 2016, and combined EPA data that calculated the toxic dose effects of 8 plants and animals with U.S. geological survey data on dozens of agricultural chemicals used each year. . Scientists have calculated a new measurement method they call the total applied toxicity of these eight species and the trend over time.
“Many times, politicians, media, and scientists are just talking about quantity. They always argue: “Well, we use fewer pesticides, so things get better. “This is not necessarily true. “Sometimes it is true, but not always. “
Schultz said that the industry has been developing new pesticides, “these new compounds are usually more toxic.” They include neonicotinoids, and they are related to one of the many reasons for the decrease in the number of bees.
Schultz said that the newer insecticides are more targeted at animals without backbones, lest birds and mammals survive, but this means that insects such as pollinators will be poisoned.
He said that some of the land plants and aquatic invertebrates eaten by birds and mammals, including dragonflies and may, are the same, adding that future research should focus on the higher end of the food chain.
Chris Novak, president of the pesticide industry group CropLife America, said in an e-mail: “It must be pointed out that this study found that the acute toxicity of humans and mammals in the past few decades Has been greatly reduced.”
Novak pointed out that pesticides have undergone extensive research and “only one out of every 10,000 discoveries has an 11-year journey from the laboratory to the market.”
University of Connecticut entomologist David Wagner (David Wagner) said that a new generation of pesticides are more harmful to insects, which is not surprising, for many reasons, insects are being reduced. But Wagner said that this latest study did not provide the necessary data to prove that “pesticides are the main driving force behind the decline of insects.”