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- Evaluation of valproic acid toxicity in duckweed, Lemna minorPublication . Machado, Beatriz; Prudêncio, Cristina; Ferraz, Ricardo; Barros, PiedadeIn the last years the contamination of water caused by drugs has increased significantly. The main cause is the increase of the number and quantities of drugs that is being used. Many of these compounds cannot be removed effectively by wastewater treatment plants. This problem affects the water cycle and, consequently, all the environment as well as the human health, so it is important to find new methods that can help the removal of drugs from the water. This research is aimed to understand the influence of different concentrations of valproic acid on the growth of the duckweed Lemna minor. After 7 days of exposure it was analysed the number of fronds, the length of the root and the chlorophylls content. The chlorophylls of the Lemna minor samples were analysed by spectrophotometry. The number of fronds was influenced by the concentration of valproic acid. The higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) showed an inhibitory effect while the lower concentrations (0,005 mg/mL; 0,0001 mg/mL) showed a stimulating effect. Relative to the control, the number of fronds was lower in the higher concentrations and higher in the lower concentrations. The root length was affected in all the concentrations. Comparative to the control the higher concentrations presented a diminution of the root’s length while the higher ones had an increase. Like the other parameters the concentration of chlorophylls was affected in all the samples. In the higher concentrations (0,1 mg/mL; 0,05 mg/mL; 0,025 mg/mL) the quantity was lower, comparatively to the control, and in the lower ones (0,01 mg/mL; 0,005 mg/mL; 0,0001 mg/mL) it was higher. In general, the valproic acid influenced all the parameters evaluated: number of fronds, length of the root and concentration of chlorophylls. In the higher concentrations it is notable an inhibitory effect while the lower concentrations have a stimulating one.
- Ecotoxicity of valproic acid in Lemna minorPublication . Machado, Beatriz; Prudêncio, Cristina; Ferraz, Ricardo; Barros, PiedadeThe water pollution represents one of the most serious ecological challenges. Over the last years the use and consumption of pharmaceuticals has increased,and this is reflected in the rise of water contamination. Many drugs cannot be efficiently removed by wastewater treatment and ended up being released into the aquatic environment. Valproic acid is an anticonvulsive and mood stabilizer medication that has been found in the aquatic environment. Although some effects of this drug on small mammals and fish are known, its ecotoxicity in plants has not yet been evaluated. Lemnaminor is widely used as a bioindicator of water quality. This aquatic macrophyte has been applied for remediation studies and has shown effective results. The aim of this study is to study the ecotoxicity of valproic acid on the growth of Lemna minor. Lemna minor was exposed to six different concentrations of valproic acid for 7 days. During this time the number of fronds was analyzed. After the test some parameters were evaluated: area of fronds, root length and chlorophylls content. The chlorophylls were analyzed by spectrophotometry. At the higher concentration (0,1 mg/L) of valproic acid, the number of fronds was significantly lower than the control. Also, chlorophyll content was lower at 0,05 mg/L and 0,1 mg/Lfor chlorophyll a, b and carotenoids and at 0,025mg/L; 0,05mg/L and0,1mg/L for total chlorophyll. The rootlength was significantly lower at the higher concentrations(0,025mg/L; 0,05mg/L and 0,1mg/L), comparatively to the control. The fronds area didn’t show any significant difference when compared to the control. Valproic acid influenced the number of fronds,length of the root and concentration of chlorophylls and at the higher concentrations it is notable a significant inhibitory effect.