Toxicity assessment of commercial herbicide formulations to Eisenia andrei (Bouché, 1972) in oxisols

Abstract

The use of long-residual herbicides can have adverse effects on terrestrial ecosystems. This study assessed the acute and chronic toxicity and avoidance behavior of Eisenia andrei earthworms exposed to nominal concentrations of clomazone, indaziflam, and sulfentrazone, using recommended commercial formulations for sugarcane cultivation. The formulations included Gamit® 360 CS (360 g L−1 of the active ingredient - a.i. - clomazone), Boral® 500 SC (500 g L−1 of a.i. sulfentrazone), and Alion® (500 g L−1 of a.i. indaziflam). Boral® 500 SC induced avoidance at concentrations as low as 1 mg kg−1, while Gamit® 360 CS and Alion® exhibited higher avoidance at 50–75 mg kg−1 and 75–100 mg a.i. kg−1, respectively. Reproduction tests showed significant impacts from Gamit® 360 CS (EC50: 0.572 mg kg−1, EC10: 0.2144 mg kg−1) and Boral® 500 SC (EC50: 0.3941 mg kg−1, EC10: 0.134 mg kg−1). Acute toxicity tests indicated moderate toxicity for Gamit® 360 CS (LC50: 184.12 mg kg−1) and Boral® 500 SC (LC50: 1000 mg kg−1). Gamit® 360 CS reduced biomass at all concentrations, while Boral® 500 SC influenced only at higher levels (500 and 1000 mg kg−1). Results suggest significant acute risks with Gamit® 360 CS, while chronic exposure raises concerns for both Gamit® 360 CS and Boral® 500 SC, indicating potential long-term risks. Alion®'s acute effects were inconclusive, but chronic exposure hints at a possible risk. These findings provide crucial insights for environmental agencies establishing protective limits against herbicide exposure to non-target soil invertebrates.