Phytotoxicity and genotoxicity assessment of imazethapyr herbicide using a battery of bioassays.

MAGDALENO A. ; PERALTA GAVENSKY M.; FASSIANO A.V.; RÍOS DE MOLINA M.C.; SANTOS M.; MARCH H.; MORETTON J.; JUÁREZ A.B.

ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2015 vol. 22 p. 19194 - 19202

0944-1344

The imazethapyr herbicide (formulation Verosil®)was evaluated for phytotoxicity and genotoxicity using a batteryof bioassays: (1) the growth inhibition of the green algaPseudokirchneriella subcapitata, (2) the root growth and germinationof the higher plant Lactuca sativa, (3) the geneticdamage using the Salmonella/microsome test, and (4) theaneugenic and clastogenic effects on Allium cepa. TheVerosil® formulation was highly toxic to the non-target greenalga (median effective concentration (EC50)=1.05±0.05 mgactive ingredient (a.i.) L−1), and concentrations above 10 mga.i. L−1 inhibited root elongation in lettuce: relative growthindex (RGI) between 0.28±0.01 and 0.66±0.10. Nogenotoxic effect was observed in Salmonella typhimurium at100 mg a.i. L−1, either with or without the microsomal fraction.However, significant differences in the frequency ofchromosomal aberrations in anaphases and telophases (bridges,chromosome fragments, and vagrants) were observed inA. cepa at concentrations between 0.01 and 1 mg a.i. L−1 withrespect to the control. The frequencies of micronuclei showedsignificant differences with respect to the control at concentrationsbetween 0.001 and 0.1 mg a.i. L−1. A very high mitoticindex (MI=93.8±5.8) was observed associated with ahigh number of cells in the prophase stage at 100 mg a.i.L−1, indicating cytotoxicity. These results showed thatimazethapyr is toxic to the non-target populations in bothaquatic and terrestrial ecosystems. This herbicide might alsoexert clastogenic and aneugenic mitotic damage in higherplants. Therefore, the imazethapyr formulation may constitutean environmental risk to plants.