Phytotoxic and cytogenotoxic assessment of hydroquinone using plant and animal bioassays.

Hydroquinone (HQ) is a phenolic compound widely used in industrial processes and recognized as a priority pollutant. However, information on its ecotoxicological effects on plants and aquatic organisms remains limited. This study evaluated the toxicity of HQ using bioassays with the plant species Allium cepa and Lactuca sativa and the freshwater mussel Limnoperna fortunei. In A. cepa, nine HQ concentrations ranging from 0.125 mg/L to 200 mg/L were tested, and cytogenotoxicity was assessed through the mitotic index (MI), micronucleus (MN) frequency, and chromosomal abnormalities. In L. sativa, phytotoxicity was evaluated by seed germination and root growth at concentrations from 5 mg/L to 200 mg/L. Mussels were exposed to HQ concentrations from 0.0625 mg/L to 0.5 mg/L, and nuclear abnormalities in hemocytes were analyzed. HQ significantly reduced the MI and induced genotoxic effects in A. cepa, and inhibited seed germination and root growth in L. sativa. No significant increase in hemocyte nuclear abnormalities was observed in L. fortunei. These findings indicate that environmentally relevant HQ concentrations did not induce genotoxic effects in mussels, whereas higher concentrations ≥25 mg/L caused phytotoxic and cytogenotoxic effects in plants. This study provides novel in vivo data that address current gaps in the understanding of HQ ecotoxicity.