Fate of Neonicotinoid Insecticides in Water and Wastewater Treatment Systems

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Project Period: 
2017 to 2018
Collaborating Institution(s): 
University of Iowa, Department of Civil and Environmental Engineering
U.S. Geological Survey
Project Investigator(s): 
David M. Cwiertny
Gergory H. LeFevre
Dana W. Kolpin

Neonicotinoids represent one of the most heavily used pesticide classes, particularly for corn and soy production. Despite their ubiquity in Midwestern water resources, little is known about their fate in the environment, particularly engineered treatment systems intended to mitigate risk their exposure. This work is motivated by our overriding hypothesis that chemical and biological processes used in conventional treatment alter the structure of neonicotinoids so as to remove their specificity to invertebrates, thereby exposing non-target organisms, including humans, to unanticipated risks arising from their bioactive transformation products in finished water and effluent. Our research plan integrates laboratory studies simulating conventional water and wastewater treatment processes with monitoring of neonicotinoid removal and transformation at the University of Iowa Water Treatment Plant. Outcomes will provide the first insights into best practices for neonicotinoid removal during treatment and better understanding of the risks associated with their formation of unintended transformation byproducts.

Project Results: 

The research measured emerging contaminants in drinking water from non-point sources and determined their fate and transformation, as well as developed new innovative technologies, consistent with the 1987 Iowa Groundwater Protection Act. The study demonstrated, for the first time in the world, that specific emerging pesticides are present in drinking water, which presents a human health exposure route. This work to assess fate and transformation could potentially help to inform future toxicology studies.

These discoveries will improve the informational available to every Iowan on the quality of their drinking water. Additionally, the technologies used in conventional and advanced water treatment systems will better enable municipalities and citizens to have the safest water possible. The CHEEC seed grant was further leveraged to obtain a highly competitive federal research grant, which will further illuminate research related to safe water. Researchers are currently working to develop new technologies for water quality sensing that could make detection safer, faster, and less expensive, and even create a new start-up venture. The research conducted in the CHEEC seed grant, which has been substantially leveraged with other resources, provides direct and tangible benefits to improve water quality and protect public health for the people in the state of Iowa. 

Key findings of the project include:

  1. -Neonicotinoid insecticides, present in rivers used for drinking water sources, are present in finishing drinking water, which we discovered for the first time
  2. -Neonicotinoids are not removed using conventional coagulation-floculation drinking water treatment
  3. -More advanced treatment methods, such as granular activated carbon, were significantly more effective at removal
  4. -Drinking water disinfection processes (i.e., chlorination) can transform neonicotinoids present in drinking water
  5. Low level human exposure to neonicotinoids may occur via drinking water.



Klarich, K. L., Pflug, N. C., DeWald, E. M., Hladik, M. L., Kolpin, D. W., Cwiertny, D. M., & LeFevre, G. H. (2017). Occurrence of neonicotinoid insecticides in finished drinking water and fate during drinking water treatment. Environmental Science & Technology Letters, 4(5), 168-173.