The Environmental Protection Agency (EPA) has determined that popular pesticides linked to declining bee populations also pose a threat to birds and, in some cases, small mammals and insects.
The EPA released preliminary scientific assessments of four chemicals from the neonicotinoid or "neonic" class of insecticides on Friday as part of an ongoing review that environmentalists and farmers are watching closely. Previous EPA assessments echoed research showing that neonics can harm the bees we rely on to pollinate crops when sprayed on cotton and certain fruits and vegetables.
"The EPA's assessments confirm neonicotinoid pesticides are extremely harmful to birds and aquatic life at the very center of our ecosystems," said Lori Ann Burd, director of the Center for Biological Diversity's environmental health program, in a statement.
Environmentalists blame all four of the neonic pesticides under review at the EPA -- clothianidin, thiamethoxam, dinotefuran and imidacloprid -- for declining populations of honey bees, butterflies and other pollinators, including several endangered species. Of the four, imidacloprid is probably the most widely used and controversial.
In their most recent assessment, EPA scientists determined that imidacloprid poses an "acute risk" to birds when sprayed on crops. Birds, small mammals and insects could also be harmed if they eat crop seeds treated with the pesticide.
The findings echo a report published earlier this year that found imidacloprid and the controversial organophosphate pesticide chlorpyrifos can impair songbirds' ability to find their way while migrating. Environmentalists are also concerned that the chemical may pose health risks to humans, including cancer and increased rates of autism in young children.
In 2016, the EPA also found that imidacloprid "potentially poses risk to [bee] hives when the pesticide comes in contact with certain crops that attract pollinators," according to a preliminary assessment released at the time.
Further EPA assessments determined that the other three neonics do not pose a "significant" threat to honey bees, although "spray applications to a few crops" including cotton, berries and cucumbers could harm bees that come in contact with the chemical residue.
However, two of these pesticides threaten birds and other small animals when applied directly to seeds before they are planted. Both clothianidin and thiamethoxam can harm birds and small mammals that forage through seed stocks for food, according to the latest EPA assessments. Smaller seeds that receive heavier applications of the chemicals, such as lettuce and sugar beet seeds, are particularly dangerous to hungry critters.
"The harms for imidacloprid, clothianidin and thiamethoxam were quite high due to the use of these three on treated seeds that would then be ingested by the birds," said Nathan Donley, the senior scientist at the Center for Biological Diversity, in an email to Truthout. "Dinotefuran is not used to treat seeds, so the harms were much lower and barely exceeded the agency's level of concern."
In 2015, the EPA temporarily halted the approval of new outdoor uses of neonic pesticides until the risk assessments are complete. The agency recently rolled out a new policy restricting neonicotinoid applications on flowering plants when farmers hire beekeepers to help pollinate their crops, but the new labeling requirements do little to protect wild pollinators.
However, so far, the EPA has been reluctant to place new restrictions on sales of neonics while it conducts its review of the chemicals, a process that the agency plans to complete within the next two years. Environmentalists point out that the European Union has placed a temporary ban on neonics as scientists work to determine whether they are responsible for declining bee populations, and Canada has proposed a ban on imidacloprid because it has been found to kill aquatic insects that make up crucial links in the food chain.
"The EPA's own research leaves no question that neonicotinoids pose unacceptable risks," said Burd. "But while other developed nations wisely restrict use of these dangerous poisons, the United States has refused to take even the most basic steps to protect our wildlife from neonics."
In October, the Natural Resources Defense Council filed a lawsuit asking a federal court to take the four neonics off the market until the EPA studies their impacts on endangered species of insects.