Related Experiment Video
Updated: Nov 21, 2025
08:49
Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff
Published on: May 15, 2017
10.9K
Repeated insecticide pulses increase harmful effects on stream macroinvertebrate biodiversity and function
Peter Wiberg-Larsen1, Ulrik Nørum2, Jes Jessen Rasmussen3
1Institute for Bioscience, Aarhus University, Vejlsoevej 25, D 8600, Silkeborg, Denmark.
Environmental Pollution (Barking, Essex : 1987)
|January 18, 2021
Summary
Sequential lambda-cyhalothrin insecticide pulses significantly altered stream macroinvertebrate communities and reduced leaf decomposition. These impacts persisted for at least one month, highlighting risks from repeated pesticide exposures.
Area of Science:
- Environmental Toxicology
- Aquatic Ecology
- Insecticide Ecotoxicology
Background:
- Insecticides pose risks to aquatic ecosystems.
- Understanding the impact of repeated insecticide exposure is crucial for effective environmental risk assessment.
Purpose of the Study:
- To investigate the effects of multiple lambda-cyhalothrin pulses on stream macroinvertebrate communities and leaf decomposition.
- To assess the impact of varying exposure frequencies on aquatic ecosystem functions.
Main Methods:
- Mesocosm and instream stream channels were exposed to one, two, or four pulses of lambda-cyhalothrin.
- Macroinvertebrate taxonomic composition, drift, and leaf litter decomposition were monitored before and after exposure.
- Control channels were maintained for comparison.
Main Results:
- Lambda-cyhalothrin exposure significantly increased macroinvertebrate drift, particularly for sensitive species like Gammarus pulex.
- Macroinvertebrate community composition shifted progressively with increased exposure frequency.
- Leaf decomposition rates significantly decreased with more frequent insecticide pulses.
Conclusions:
- Repeated lambda-cyhalothrin exposures cause lasting changes in stream macroinvertebrate communities and impair ecosystem functions.
- Species sensitivity to lambda-cyhalothrin drives community-level changes, even with recolonization.
- Sequential exposures are critical for evaluating the full ecological impact of insecticides in streams.
