Determination of heavy metal accumulation and oxidative stress level in L. gibba L. and L. minor L. adapted in secondary effluent

The organisms accumulating risky pollutants such as heavy metals, pesticides, organic and inorganic toxins and radioactive materials from the environment are used widely in waste water treatment. Early detection of the effects of pollutants on biochemical processes has a big importance on environment and the health of living organisms. Glutathione among antioxidative compounds which removes oxidative stress from the pollutants and other environmental effects, and the change in vitamin amounts are accepted as early indicators (markers) of the pollution. In this study, it is aimed to determine the capability of accumulation of heavy metals of aquatic plants Lemna minor L. and Lemna gibba L. from the effluent of municipal wastewater system of Elazig and the determination of the effects of these pollutants on amounts of MDA and GSH, GSH/GSSG ratio in these plants and, the effects on nonenzymatic antioxidant vitamins (A, E and C) levels. With this aim, L. gibba and L. minor were placed within the reactors separately. Macro and micro element levels in the samples of treated and effluent waters from the reactors and in the plants were analyzed in ICP-MS analyzer. In addition, MDA and GSH levels, GSH/GSSG ratio and non enzymatic anti oxidative vitamin (A,E and C vitamins) were analyzed in HPLC device. When metal levels in the plants from the reactors were compared with the control sample, it was seen that MDA level which is an indicator of stress in plants was detected to be significantly high in L. minor and L. gibba fronds. It was also observed that GSH level was considerably higher than the control group and moderately higher than the control group in L. minor and L. gibba fronds respectively. GSH/GSSG ratios were higher than L. gibba fronds and generally lower in L. minor regarding control group. Vitamin A in L. gibba fronds gave varying responds. During the process, Vitamin A increased between 3rd and 5th days in L. minor with respect to the control group but decreased continuously after the 3rd day in L. gibba. Vitamin E decreased continuously in L. minor and it also decreased in L. minor except the 3rd day. Vitamin C was significantly higher than the control group in L. minor fronds and also increased on the 1st day and fluctuated on the following days. Pearson Correlation Test was used in analyzing the relations between the parameters statistically. SPSS software was used in analysis of the study. Considering the correlation between the control group and the samples from the reactors, p<0.05 was accepted meaningful.