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USGS2025

Pesticide concentrations in multiple physical and biological stream matrices are impacted by a bioenergy production facility receiving pesticide coated corn seeds

Insecticide and fungicide seed coatings have become prevalent in conventional agriculture in recent decades. From 2015 to 2021, the AltEn bioenergy plant (Mead, Nebraska, USA) generated ethanol from almost 100% unused/expired treated corn seeds. This use of these seeds for ethanol production resulted in the accumulation of large amounts of contaminated wastewater and solid residue, a portion of which was applied to surrounding farmland. To better understand the potential long-term environmental effects from the processing of treated seeds at this facility, five nearby stream sites were sampled in 2022 after the closure of the plant; these included two sites directly impacted by AltEn, one upstream, and two downstream of the impacted sites. Water and sediment were collected in March through July, and algae and fish samples were collected in July for chemical analysis. Overall, 60 pesticide compounds (parents and transformation products) were detected in one or more matrices, including 23 fungicides, 20 insecticides, 16 herbicides, and 1 bacterial growth inhibitor. Pesticide results (maximum detection frequency, maximum concentration) varied substantially by environmental compartment: water (100% multiple pesticides; 4,600 ng L −1 thiamethoxam transformation product (NOA-407475)), algae (100% multiple pesticides, 190 ng g −1 atrazine), sediment (60% dithiopyr, 2.3 ng g −1 acetochlor) and fish (20% pyraclostrobin, 2.2 ng g −1 atrazine). Pesticides associated with treated corn seeds (e.g., insecticides clothianidin, thiamethoxam; fungicides fluoxastrobin, thiabendazole) were detected at significantly higher concentrations ( p < 0.05) in stream water from sites impacted by the AltEn facility compared to non-impacted sites. Study results indicate that pesticides associated with the AltEn facility continue to be a source of contaminants to aquatic systems after the plant’s closure in 2021.

Environmental Toxicology and Chemistry↗

USGS2025

Tapwater-contaminant mixtures and risk in a biofuel-facility impacted private-well community

We assessed private-well drinking water (DW) at the point of use ( i.e. , tapwater, TW) within a rural Nebraska community around a state-closed biofuel facility, which used pesticide-treated corn seed as feedstock for ethanol production. Organic (485), inorganic (34), and microbial (13) analytes were assessed at 15 locations in June 2022, to evaluate the relative contribution of facility-consistent pesticides (seed-treatment fungicides and insecticides) to overall TW-contaminant exposures and predicted human-health risks. Thirty-three organics (12 pesticides) and 28 inorganics were detected, the former including the fungicide sedaxane, insecticide chlorantraniliprole, and multiple neonicotinoid insecticides/degradates, all consistent with seed treatment and respective biofuel-facility waste. Assessment of pesticides only at extant point-of-use (POU) treatment taps at three sites demonstrated complete elimination of all TW-pesticide detections. Based on detection of maximum pesticide concentrations in a home located downstream along a creek capturing facility runoff, pesticides only were assessed in January 2023 again at this home and at three adjacent locations, confirming results at the former and documenting decreasing TW-pesticide concentrations, including neonicotinoids, with increasing distance from the creek. Human-health DW benchmarks are not available for many detected pesticides, including the detected fungicide and insecticides, but precautionary screening levels were exceeded frequently due to multiple inorganics. The results indicate that exposures to multiple (median: 4.5; range: 1–7) co-occurring TW contaminants of potential human-health concern are common, warranting consideration of point-of-entry or POU treatment(s) throughout the community to reduce or eliminate unrecognized exposures to TW contaminants, including facility-associated pesticides in down-gradient locations. More broadly, results emphasize the importance of continued characterization of private-TW exposures, employing a environmentally informative analytical scope, to identify and mitigate risks of unrecognized exposures in private-well-dependent rural communities.

Nebraska↗