Uptake of PAHs and metals by plants in arid environment

Study of plant uptake of PAHs with the concurrent presence of metals in laboratory conditions was done with the aim to resemble specific combinations of natural environment. Toxicological response of seedlings was tested to define treatment conditions or possible interferences. The levels of PAHs and metals in the treatments were set up to have no toxic effect on plant growth. The complexity of concurrent contamination was demonstrated in a laboratory with soil. No visual differences were observed among various dose treatments of Cu and Zn with organics three PAHs, Phenanthrene (Phen), Acetoanthrancene, and Benzo(a)pyrene (BaP). The metal analysis by ICP/OES discovered the obstruction of BaP and Phen, to Cu uptake; and the uptake of Zn by alfalfa plants was blocked by the presence of BaP in soil but highly improved by Phen. Glutathione Transferase Specific Activity (GST SA) was used as a biomarker to illustrate plant’s response to environmental stressor. GST SA was determined in alfalfa and radish seedlings in treatments with BaP and Phen, and in radish on soil microcosms. The GST SA changes in alfalfa in vitro resulted in significant difference whereas GST SA in radish in soil showed no significant difference. The study identifies that GST SA may serve as an excellent model system for the investigation of stress-induced response in vitro. However, plant species behave differently in response to environmental stress. Plants comprise more enzymatic pathways to be included in the model. Soil microcosms consisted of undisturbed core field soil were used to mimic the real world situation in the study the effect of soil types on plant’s response to organic contaminants. Though no significant difference was observed in plant growth, enzymatic levels, and plant uptake of PAHs among treatments, soil types did have impacts on these factors. Organic treatment in soil was assessed in radish plants by GC/MS. Sample preparation process was optimized by Stir Bar Sorptive Extraction and chemical analysis was performed in Thermal Desorption coupled with Gas Chromatography and Mass Spectrometry. The concentrations in aerial part were recorded from 12 to 140 ng of BaP and around the 13 ng of Phen. In roots, BaP concentration was from11 to 1440 ng, and the maximum of Phen was 173 ng. Bioconcentration of PAHs in root and translocation of these organics were observed in every treatment in soil