Hotter Waters, Higher Risks: How Climate Influences the Toxicity of a Common Insecticide in Aquatic Ecosystems

Obi Cicadabird

18-10-2025

“Weirdness is not a flaw. It’s a frequency.”

In Kingfisherish Wandering [1]

© Wix

The global use of the insecticide imidacloprid (IMI)—one of the most widely applied neonicotinoids for pest-controlling activity and crop applicability—has raised growing concern about its ecological impact [2-4]. A recent review by Lemessa B. Merga and Paul J. Van den Brink [5] systematically analyzed worldwide data to understand how IMI’s toxicity varies across climatic zones, revealing that tropical and subtropical ecosystems are far more vulnerable than temperate ones.

IMI residues are now found in nearly all types of water bodies—from rivers and wetlands to groundwater and estuaries—with concentrations ranging from 0.00019 to 59 µg/L. Alarmingly, 75 % of average values exceed chronic safety thresholds for freshwater invertebrates, threatening biodiversity and ecosystem services such as water purification and nutrient cycling. These high levels are attributed to agricultural intensification and poor regulation in the Global South, where IMI use remains largely unmonitored despite its ban for outdoor applications in the European Union [6].

The study found dramatic differences in toxicity thresholds across regions. The no-observed-effect concentrations (NOECs) for aquatic arthropods ranged from 0.5–7.5 µg/L in temperate regions to <0.01–0.1 µg/L in tropical ones—indicating a tenfold increase in sensitivity. Insects such as mayflies (Cloeon and Caenis species) were particularly affected. These results suggest that benchmarks derived from temperate data may underestimate ecological risks in warmer climates, highlighting the urgent need for region-specific environmental standards.

Temperature emerged as a critical factor. Higher water temperatures accelerate metabolic processes, increasing pesticide uptake and biotransformation into more toxic metabolites. Lower dissolved oxygen and differing nutrient conditions in tropical waters further amplify these effects. The authors call for integrating temperature correction factors and local species data into global risk assessment frameworks to ensure fair and accurate ecological protection [5].

When industrial and agricultural decisions neglect ecological intelligence, they erode not only biodiversity but also individual and social peace, as communities dependent on clean water and healthy ecosystems face worsening insecurity [7]. Cultivating NQ across policymaking, education, and agriculture thus becomes essential to restore balance between human progress and ecological harmony [8].

References

[1] Nguyen MH. (2025). Kingfisherish Wandering. https://www.amazon.com/dp/B0FVLLLXNW/

[2] Tang FHM, et al. (2021). Risk of pesticide pollution at the global scale. Nature Geoscience, 14, 206-210. https://doi.org/10.1038/s41561-021-00712-5

[3] Mamy L, et al. (2025). Impacts of neonicotinoids on biodiversity: a critical review. Environmental Science and Pollution Research, 32(6), 2794-2829. https://doi.org/10.1007/s11356-023-31032-3

[4] Morrissey CA, et al. (2015). Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: a review. Environment International, 74, 291-303. https://doi.org/10.1016/j.envint.2014.10.024

[5] Merga LB, den Brink PJV. (2025). A review of climatic zone-related variations in toxicity of imidacloprid towards aquatic species and ecosystems. Environmental Pollution, 386, 127267. https://doi.org/10.1016/j.envpol.2025.127267

[6] European Commission. (2018). Commission implementing regulation (EU) 2018/783 of 29 may 2018 amending implementing regulation (EU) No 540/2011 as regards the conditions of approval of the active substance imidacloprid.

[7] Nguyen MH, Ho MT, La VP. (2025). On “An” (安): Inner peace through uncertainty, nature quotient, and harmony with Dao. http://books.google.com/books/about?id=NIKMEQAAQBAJ 

[8] Vuong QH, Nguyen MH. (2025). On Nature Quotient. Pacific Conservation Biology, 31, PC25028. https://doi.org/10.1071/PC25028