Diazinon and permethrin mitigation across a grass-wetland buffer

Area of Science:

• Environmental Science
• Agricultural Engineering
• Ecotoxicology

Background:

• Edge-of-field vegetated buffers are common practices for mitigating pesticide runoff from agricultural lands.
• Buffer efficacy in pesticide removal is highly variable, influenced by pesticide properties, vegetation type, and hydrological conditions.

Purpose of the Study:

• To evaluate the pesticide retention capabilities of a grass-wetland buffer system compared to a control system under simulated agricultural runoff conditions.
• To assess the differential retention of diazinon and permethrin isomers by these buffer systems.

Main Methods:

• Experimental evaluation of two systems: a control (no vegetation) and a grass-wetland buffer.
• Application of simulated storm runoff containing diazinon and permethrin (cis- and trans-isomers).
• Quantification of pesticide retention percentages and calculation of half-distances for concentration reduction.

Main Results:

• Both systems demonstrated low diazinon retention (mean 9.6%).
• Grass-wetland buffers achieved significantly higher retention of cis-permethrin (83%) and trans-permethrin (85%) compared to the control (39% and 44%, respectively).
• Half-distances for permethrin isomers were shorter in grass buffers, indicating more efficient removal.

Conclusions:

• Pesticide retention efficacy is strongly dependent on pesticide properties, with more strongly sorbing compounds like permethrin being retained more effectively.
• A single management practice may face challenges in mitigating multiple pesticide types simultaneously.
• Integrated management strategies, particularly those incorporating vegetation, are crucial for enhancing pesticide runoff mitigation.