Comparative ecotoxicological assessment of two glyphosate-based herbicides using <i>Panagrellus redivivus</i> and <i>Artemia salina</i> immobilization bioassays

Glyphosate-based herbicides (GBHs) are among the most widely used chemical agents in modern agriculture, raising environmental and health concerns due to their persistence in the environment. The aim of this study was to examine the toxicological effects attributed to exposure to two GBHs: a newly released sales-restricted commercial formulation (XEQUE MATE HT IHARA® - GBHn) and a publicly available gardening formulation (CITROMAX MAX 20 - GBHg), using immobilization bioassays with <i>Artemia salina</i>, a saltwater filter-feeding invertebrate, and <i>Panagrellus redivivus</i>, a free-living nematode. Organisms were exposed to increasing concentrations of each herbicide, and immobilization was assessed after 24 hr. Both GBHs initiated dose-dependent toxicity, with immobilization reaching 100% for GBHg in <i>A. salina</i> and 73.4% for GBHn in <i>P. redivivus</i> at the highest concentration tested. The Sensitivity Index (SI) indicated that <i>A. salina</i> appeared to be more sensitive to GBHg, while <i>P. redivivus</i> was more susceptible to GBHn. Despite these differences, both herbicides exhibited similar Overall Sensitivity Index (OSI) values-0.73 for GBHg and 0.75 for GBHn - indicating comparable overall toxicity profiles. These findings suggest that GBHn does not present a markedly higher environmental risk than existing formulations. However, the results emphasize the importance of continuous ecotoxicological monitoring of new glyphosate formulations.