Bee-killing pesticides found in California waterways

Clean water

Data Visualization


Ben Grundy

Former Conservation Campaign Associate, Environment California

Bees are dying in record numbers in California. A major factor is the overuse of bee-killing pesticides. Neonicotinoids or “neonics” disrupts the nervous system of insects and  causes paralysis and death. 

Imidacloprid was the first neonicotinoid registered for use in 1991. Since then, this chemical became the most widely used insecticide in the world. Many gardeners, park maintenance staff or landscape professionals don’t realize that when they apply this legal insecticide to lawns and plants, they are exposing bees to this potent neurotoxin. The chemical doesn’t just affect the plants, it also gets into the soil and washes into streams and rivers where it can harm other wildlife. 

Samples being captured at a streamPhoto by AdmICrunch | CC-BY-2.0

Water sampling conducted by California officials found that 97% of urban water samples in the Central coast and Southern California contained imidacloprid at levels above EPA’s chronic benchmark for harm to aquatic ecosystems.

This widespread contamination indicates widespread use of these bee killing pesticides throughout urban environments. This is bad news for bees, and one in three native bee species in California are now at risk of extinction. But bees are sort of like the canary in the coal mine for the ecosystem where we live. Recent studies show that neonics also harm birds, fish, frogs, deer and human health.

We compiled the results from California water samples since they began testing for this chemical. Explore the map and graph below to see your community’s imidacloprid contamination levels in waterways and how the problem has grown over the past two decades. 


Laura Deehan

State Director, Environment California

Laura directs Environment California's work to tackle global warming, protect the ocean and fight for clean air, clean water, open spaces and a livable planet. Laura stepped into the State Director role in January, 2021 and has been on staff for over twenty years. She has led campaigns to make sure California goes big on offshore wind and to get lead out of school drinking water. As the Environment California Field Director, she worked to get California to go solar, ban single use plastic grocery bags and get on track for 100% clean energy. Laura lives with her family in Richmond, California where she enjoys hiking, yoga and baking.

Ben Grundy

Former Conservation Campaign Associate, Environment California

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