The California Senate will soon decide whether to rein in the use of insecticides with nerve toxins so powerful that a tablespoonful can kill upwards of 1 billion bees.
Assembly Bill 2146, introduced by Assemblywoman Rebecca Bauer-Kahan, D-Orinda, would ban use of neonicotinoid (“neonic”) insecticides in most non-agricultural outdoor settings, including lawns, gardens and golf courses. It would mark a major step toward curbing pervasive neonic contamination.
It’s not just bees that are affected. Apart from their well-documented role in massive losses of bees, butterflies and other pollinators, neonics have been linked to dramatic declines in bird species, birth defects in wildlife and the collapse of a previously stable fishery. As a former public health physician, I am also concerned about their potential human health risks.
Introduced in the 1990s, neonics have become the most widely used pesticides in the world. Designed to be absorbed by plant tissues, neonics can make all plant parts — including the stem, leaves, flowers, pollen, fruits and vegetables — toxic to a wide variety of insects for months or longer. Their frequent presence in edible produce explains, in part, why they were detected in the bodies of about half the U.S. population several years ago and, more recently, in 92% of a geographically diverse group of pregnant women.
Intended to exterminate destructive pests, these chemicals also kill many beneficial organisms besides pollinators, including songbirds, earthworms and aquatic invertebrates that serve as an important food source for many fish and birds. Even when neonics don’t kill outright, they cause numerous detrimental effects in bees, such as reduced ability to forage and pollinate, decreased reproduction and impaired immunity.
Residential yard products can contain neonics at concentrations far higher than those allowed in agriculture, making our gardens, trees and other plants poisonous to visiting pollinators. These chemicals can also drift or be carried offsite and leach into creeks, rivers and lakes. Neonics persist from months to years in soil and have extensively contaminated our environment, appearing in 67% of Northern California urban surface waters at levels considered toxic to aquatic organisms at the base of the food chain.
Neonics’ history resembles that of DDT and PCBs (both now banned nationwide) and other toxic chemicals: widespread adoption and use for many years before the extent of their harmfulness was discovered. Neonic sales soared in part because, compared with earlier pesticides, they are less toxic to people after short-term, higher-level exposures. However, while relatively few studies of neonics’ health impacts have been published, there is little doubt that people are at risk from chronic, low-level exposures.
In research involving chronic human exposures, neonicotinoids have been associated with memory loss, tremors and other neurological symptoms, decreased testosterone, lower sperm counts and motility and, in the case of prenatal exposures, autism and birth defects of the heart and brain. Laboratory research on animals and cell cultures also links neonics with effects on the nervous and immune systems, hormone disruption, DNA damage and problems in reproduction, including birth defects and stillbirths. Outside the world of research, thousands of neonic poisonings have been reported to poison control centers.
Maine and New Jersey have both prohibited neonics in outdoor, non-agricultural settings, recognizing that the risks outweighed any cosmetic benefits to lawns and gardens. Experience in Europe (where most neonics were banned in 2018) shows that these products aren’t needed or can be replaced with safer alternatives.
California now has an opportunity to curb these harmful chemicals in our own backyards. The California Assembly has passed AB 2146; the state Senate will decide the bill’s fate in early August. To help protect pollinators, wildlife and people, please ask your state Senator to support AB 2146.
Dr. Michael Lipsett worked for nearly three decades in public and environmental health in California state government.