Ecotoxicological effects of paracetamol on seed germination and seedling development of wheat (Triticum aestivum L.).

In order to assess ecological risk of pharmaceutical compounds entering into agricultural ecosystems, toxic effects of paracetamol with therapeutic action on wheat (Triticum aestivum L.) were investigated as an example, using early growing and developmental indexes of wheat, including seed germination, shoot height and root length, peroxidase, superoxide dismutase, chlorophyll, and soluble protein in the seedlings. The results showed that wheat shoot and root elongation decreased significantly (p<0.05) with an increase in the concentration of paracetamol. Wheat roots were the most sensitive sites of the plants to paracetamol, and the median effect concentration (EC(50)) of paracetamol based on the inhibition of root elongation was 668.8 mg/L, which cannot be found in the practical environment in this phase. However, the low concentration of paracetamol inhibited the growth of wheat after a chronic exposure. After the 21-day exposure, 1.4-22.4 mg/L paracetamol treatment caused damage to the chlorophyll accumulation and soluble protein synthesis. After the 7-day exposure, the activity of peroxidase and superoxide dismutase in wheat leaves increased with an increase in the concentration of paracetamol in order to eliminate the peroxides produced and maintain the function of cells. However, the activity of peroxidase in wheat roots decreased significantly after the 14-day exposure, which indicated the antioxidative defensive system in wheat roots was damaged by paracetamol.