Lax pesticide guidelines endanger wildlife health, experts warn

Among nearly 800 white-tailed deer melts sent to a Minnesota state laboratory in 2019, three were from Barry Sampson, who hunts his wooded property with his nephews. His samples – along with 61 percent of the total from various landscapes across the state – contained pesticides known as neonicotinoids. “I wonder how that got to the deer,” he says, “and I’m not happy about it.”

The results, released in March, suggest how ubiquitous these chemicals have become in the environment, says Michelle Carstensen, study director for the Minnesota Department of Natural Resources. Neonicotinoids, also called neonics, began to replace older beetle repellent chemicals in the arsenals of farmers, homeowners, and gardeners in the early 1990s. They are the most widely used class of insecticides in the world today and are found in almost all conventionally grown US corn fields, as well as on flea collars, bed bug products, golf courses, and gardens.

For the past decade, neonics have been under scrutiny for their documented role in decreasing honeybee populations around the world. Recent evidence shows that the chemicals can harm a wider range of wildlife.

Last year, University of Illinois agricultural economist Madhu Khanna published a study that correlated increased usage with annual decreases in grasslands and insectivorous birds in the United States by 4 and 3 percent per year, respectively. In another study, captive deer exposed to neonics suffered from reduced fawn survival, altered organ weights, and developmental and behavioral abnormalities, in concentrations far lower than in the spleen of wild deer in Minnesota. Another ominous case emerged in a Japanese lake: after the surrounding rice fields were irradiated with neonics, the plankton numbers collapsed and triggered a collapse in the smelt and eel fisheries.

Given these results, Khanna and others believe that the guidelines for controlling chemical use are insufficient. “Current regulations are likely not enough to prevent major ecosystem impacts,” she says.

Concern about potential human health effects is growing and much more research is needed, says Melissa Perry, health scientist at George Washington University. The U.S. Centers for Disease Control and Prevention estimates that around half of the population is regularly exposed – most likely, scientists say, through food and drinking water. California is now considering adding several neonics to Proposition 65 that require health warnings on products.

Since 2018, a looming consensus on widespread hazards has led Canadian regulators to propose restricting some outdoor uses, and the European Union goes further banning the use of three common neonics on all plants. While some U.S. states are also acting, such as in a recent Massachusetts vote, to restrict consumer use outdoors, proponents say the U.S. EPA has proposed weak, minimal restrictions when the Trump administration proposed continued use approved by five popular neonics in 2020.

“It’s pretty much everything as usual,” said Dan Raichel, attorney for the Natural Resources Defense Council, of the proposal. The agency, he says, now has time to “change course” ahead of the final October 2022 deadline. He hopes these chemicals will be banned in some cases, especially where safer options such as lawn care are available.

Proponents say that another important step requires closing a loophole that hinders the EPA’s ability to regulate the most harmful and widespread use of the chemicals: as water-soluble seed coatings that are absorbed by a plant as it grows. “The very property that enables them to be systemic in plants enables them to be washed out of fields when it rains,” says entomologist John Tooker of Pennsylvania State University, who wrote an article about risks warns for food webs. Studies suggest that only 2 percent of the pesticide on a seed can get into a plant; the rest ends up in the ground, in the groundwater or in rivers and lakes.

Regulating or banning a class of pesticides that farmers and other industries rely on remains challenging, and in some cases data shows that crop yields could be affected. But the decline of birds, bees and entire ecosystems is also associated with high costs: insect pollinators contributed 34 billion US dollars to the US economy in 2012. Likewise, as bird numbers and diversity decrease, the pests increase.

In Minnesota, Sampson responded to the call for Spleen because he is worried about wildlife and hopes authorities will pursue the science. Tooker sees the rise of neonics – and the possible consequences of persistent inactivity – through the lens of another plain text: “We haven’t learned very well from Rachel Carson’s book.”

This story originally appeared in the summer 2021 issue as “Beyond Bees”. To receive our print magazine, you become a member donate today.

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