{"id":37525,"date":"2025-01-24T00:01:23","date_gmt":"2025-01-24T05:01:23","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=37525"},"modified":"2026-03-06T11:52:51","modified_gmt":"2026-03-06T16:52:51","slug":"study-finds-waterway-contamination-with-neonicotinoid-insecticide-threatening-aquatic-ecosystems-and-biodiversity","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/01\/study-finds-waterway-contamination-with-neonicotinoid-insecticide-threatening-aquatic-ecosystems-and-biodiversity\/","title":{"rendered":"Waterway Contamination Findings with Neonicotinoid Insecticide a Threat to Aquatic Ecosystems and Biodiversity"},"content":{"rendered":"

(Beyond Pesticides<\/em>, January 24, 2025) Based on data collected from government sources and independent monitoring, a multidisciplinary team of researchers at the University of Connecticut finds that 46% of Connecticut waterway samples are contaminated with levels of the neonicotinoid insecticide, imidacloprid<\/a>\u2014one of the most widely used insecticides in the United States on lawn and golf courses.<\/p>\n

The authors relied on federal data from U.S. Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS), state-level data from Connecticut Department of Energy and Environmental Protection (CT-DEEP), and a small-scale data collection study by the Clean Rivers Project funded by the nonprofit Pollinator Pathway, Inc. In their report, Neonicotinoids in Connecticut Waters: Surface Water, Groundwater, and Threats to Aquatic Ecosystems<\/a>, the researchers provide the most comprehensive view to date of neonicotinoid levels in Connecticut and offer critical recommendations for future testing within the state and nationally, given glaring data gaps.<\/p>\n

It is important to note that the authors acknowledged early in the report the “abandonment\u201d of Integrated Pest Management in \u201cthe use of neonicotinoids has coincided with and been implicated in the decline of many non-target species of insects, in particular pollinators such as bees () and monarch butterflies.\u201d<\/p>\n

They point out that the use of this systemic pesticide, typically incorporated into seeds and then integrated into the vascular system of plants and expressed through their pollen, nectar, and guttation droplets, constitutes the \u201cabandonment\u201d of a basic principle of Integrated Pest Management (IPM), \u201can approach predicated on minimizing the use of chemical pesticides in favor of pest monitoring and pesticide application only when necessary (Metcalf and Luckmann, 1994).\u201d<\/p>\n

IPM has been highly criticized<\/a> as a land management system because it lacks a uniform definition, is not limited to least-toxic pesticides, and provides no enforcement mechanism, key elements incorporated in organic certification. (See Beyond Pesticides\u2019 Parks for a Sustainable Future<\/a> program\u2014a novel initiative that works with land managers across the nation looking to move to organic practices and principles that replace chemical-intensive practices with pest prevention and management strategies, incorporating soil science and the natural cycling of nutrients.)<\/p>\n

Advocates, organic farmers, farmworkers, physicians, and community leaders alike welcome science-based and criteria-driven solutions to avoid pesticide industry greenwashing or co-optation of climate solutions to perpetuate the use of toxic products, as has been made evident with the failure of IPM to eliminate hazardous pesticide use, climate-smart agriculture and carbon markets (See Daily News <\/em>here<\/a>), and regenerative agriculture. (See Daily News <\/em>here<\/a>.)<\/p>\n

Background and Methods<\/u><\/p>\n

The three authors of this study, Steven J. Presley, PhD<\/a>, Cristopher R. Perkins, MS<\/a>, and Michael R. Willig, PhD<\/a>, are research specialists in environmental science, biology, and ecology at the Center for Environmental Sciences and Engineering and Institute of the Environment at University of Connecticut. The existing data, as referenced above, comes from a variety of federal and state-level agencies, however there was also some original data gathering.<\/p>\n

CT-DEEP collected data on macroinvertebrates along the Norwalk River between 1989 and 2020. USGS data was collected from October 2001 to January 2024 testing for imidacloprid levels in 600 surface water and 62 groundwater samples from across the state. Surface and ground water testing has not been consistent over the decades on record, leading to support for the 2024 Clean Rivers Project in the southeastern region of the state.<\/p>\n

The goal of this small-scale study was \u201cto detect and quantify the presence of six neonicotinoids<\/a> (i.e., nitenpyram, thiamethoxam<\/a>, clothianidin<\/a>, imidacloprid, acetamiprid<\/a>, and thiacloprid<\/a>) in surface waters adjacent to large expanses of manicured lawns such as golf courses, which commonly use neonicotinoids to control pests that damage turf.\u201d (See The Clean Rivers Project Neonicotinoid Data section on pages 8 to 9 of the report for more information.)<\/p>\n

Funding for this data gathering, particularly the 2024 Clean Rivers Project, came from various sources including a grassroots fundraiser<\/a> led by CT Pollinator Pathway and contributions from Sustainable CT, National Resources Defense Council, and Friends of the Earth. Norwalk River Watershed Association and East Norwalk Blue are credited with gathering water quality samples for the 2024 Clean Rivers Project. (See Acknowledgments section on page 3 of the report for more details.)<\/p>\n

The UConn authors focus on imidacloprid concentrations in aquatic systems for numerous reasons documented in the report. Imidacloprid was the only neonicotinoid detected in the 2024 Clean Rivers Project, the only neonicotinoid for which USGS has publicly available data, the \u201csingle most commonly used insecticide in the world,\u201d and an expansive listing of uses across agricultural and non-agricultural contexts.<\/p>\n

Aquatic systems were chosen given the importance of marine ecosystems for the New England economy. They were also selected since EPA has acute and chronic benchmarks for freshwater aquatic invertebrate exposure to insecticides.<\/p>\n

The researchers identify five main goals for their report:<\/p>\n

    \n
  1. \u201cDetermine long-term and seasonal patterns of the frequency of imidacloprid occurrence in surface and ground waters of Connecticut;<\/li>\n
  2. Determine seasonal variation in imidacloprid concentration in Connecticut waters;<\/li>\n
  3. Determine spatiotemporal variation in imidacloprid concentration in Connecticut surface water and groundwater;<\/li>\n
  4. Leverage long-term sampling from a site in the Connecticut River from northern Connecticut (Thompsonville) as a case study to evaluate long-term patterns in imidacloprid concentration that reflect impacts from a \u201clight urban\u201d region that contains urban, forested, and agricultural areas in Massachusetts that flow south into Connecticut; and,<\/li>\n
  5. Use the Norwalk River, a watershed with relatively little agriculture, as a case study to evaluate long-term trends in imidacloprid concentration from nonagricultural outdoor sources, and long-term trends in aquatic macroinvertebrate richness and abundance.\u201d<\/li>\n<\/ol>\n

    Main Conclusions and Recommendations<\/u><\/p>\n

    Long-Term and Seasonal Patterns: Frequency of Imidacloprid Occurrence<\/em><\/p>\n

    Researchers find that the frequency of imidacloprid detection in Connecticut waterways increased in surface waters but \u201cshow[ed] no significant temporal trend in groundwaters.\u201d Beginning after the 2012 sampling period, \u201c46% of samples collected since 2012 have detected imidacloprid, with at least half of the samples testing positive for imidacloprid during 5 of the past 9 years.\u201d It is important to note that groundwater testing for neonicotinoids has not been tested since 2017, which exacerbates the researchers\u2019 concern over \u201cthe ability of neonicotinoids to persist for extended periods of time when not exposed to sunlight.\u201d<\/p>\n

    See Daily News <\/em>here<\/a> for related analysis of pesticide contamination in water wells in Wisconsin for lessons to be learned on improving groundwater detection of pesticides.<\/p>\n

    Seasonal Variation in Imidacloprid Concentration<\/em><\/p>\n

    Similar to the previous section\u2019s results, imidacloprid detection in Connecticut surface water corresponds with the \u201cseasonal applications of neonicotinoids for agriculture and for turf grass management (e.g., lawns and golf courses.)\u201d Average imidacloprid concentrations in June and July are found to be \u201csix times greater than the USEPA freshwater aquatic chronic benchmark.\u201d<\/p>\n

    Groundwater sampling is deemed \u201cinsufficient\u201d to determine seasonal trends.<\/p>\n

    Where in Connecticut is Imidacloprid Most Concentrated?<\/em><\/p>\n

    Researchers find imidacloprid concentrations increasing closer to Connecticut coastal waterways. \u201cIn contrast, there is no significant pattern of imidacloprid concentration going from east to west in the state, there are no significant differences between water sources (surface versus ground water), and there is no interaction between water source and time or between water source and space,\u201d the researchers write. They suggest that the concentration of imidacloprid in the eastern parts of the state \u201cis greatest in agricultural and suburban areas, and the proportion of area represented by the combination of agriculture and suburban developments increases toward the coast, with northern areas often being highly forested, which is a habitat type in which the use of neonicotinoids is uncommon.\u201d<\/p>\n

    The researchers raise concerns that groundwater along the Connecticut coast \u201chas rarely been tested for imidacloprid.\u201d<\/p>\n

    The Thompsonville Case Study<\/em><\/p>\n

    The USGS site in Thompsonville tested for imidacloprid concentration from water wells in the Connecticut River Basin, finding \u201cno significant temporal change in groundwaters, but with decreasing mean imidacloprid concentration in surface waters.\u201d Researchers attribute these contrasting results with several factors including,<\/p>\n