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The study uses the Fourier transform infrared spectroscopy method to evaluate the influence of phosphogypsum from the soil on the growth and accumulation of nutrients in Spinacia oleracea. Attenuated total reflectance spectra of Spinacia oleracea roots and stems originated from plants cultivated on 28% to 52% phosphogypsum enriched soil have been studied in the 4000-600 cm À1 area. The structure of the infrared absorption bands for spinach roots and stems and for the soil where plants were grown was analyzed. Thus, it was observed that phosphorus-oxygen bonds contribution can be identified both in roots and stems absorption spectra. The significance of the research is the possibility to use the infrared investigation as rapid technique, particularly useful for agriculture, to study the extraction and assimilation process of the compounds containing phosphorus and nitrogen from the soil in which the spinach seedlings grew. In the case of this study, it was observed that the absorption of phosphorus in the spinach roots and stems has not the same effect. The analysis of obtained data indicated that the assimilation of phosphorus from phosphogypsum enriched soil induces changes in spinach roots structure that are most likely due to an increase synthesis of proteins, rather than to a decrease in carbohydrates quantity.

The aim of our investigations was to assess the potential ecotoxicological effects induced by complex chemical mixtures of anaerobically digested sewage sludge. The sensitivity of monocotyledonae cereal (Triticum aestivum L.) test plant to various sanitization treatments of anaerobic stabilized sewage sludge was evaluated. Several biometrical and biochemical response indicators were selected as endpoint in this ecotoxicological tests. Thus, the ecotoxicity of sewage sludge was evaluated through the responses of germination rate, root and stem system growth, the chlorophyll pigments and phenol contents. The sanitization treatments, respectively pasteurization and UVC exposure were applied to sewage sludge according to an experimental design wherein untreated sewage sludge was added as control sample. The results confirmed the increasing of untreated sewage sludge toxicity with the increasing of exposure time. In the case of wheat seeds kept in contact for 6 hours with the sludge treated for 30 minutes at 35°C it was observed an ascending trend of the germination rate respons with the sludge concentration. This involves a decrease of ecotoxicity compared with the one corresponding with untreated sewage sludge. Also, we appreciated a reduced ecotoxicity of low irradiated sludge than that of medium or high heat treatment in terms of germination rate inhibition measured after 14 days from the experiment beginning. By application of a medium UV dose, a low ecotoxicity was also observed, after 12h exposure time. Furthermore, the important role of phenolic compounds that protects the cell structures of the plant from environmental stress was confirmed by Principal Component Analysis.

Evaluation of radon concentration is a very difficult task and a very important issue, in relation to the protection of human health. This is especially the case when there is an increase in concentration of radon on a deterministic basis, as is the case of nearby phosphogypsum residues or geological characteristics. Radon gaseous that can be found in the environment occurs mainly from natural radioactive decay chains. The gamma ray spectroscopy is a powerful tool in order to monitor the environmental radioactivity. In this paper it have been measured and analyzed the radon concentration in a stainless steel vessel in order to provide further evidence about the deterministic chaos character of smaller time series recoded data. We have found that the fractal dimension of the radon concentration and recorded environmental parameters in the experimental vessel are strong influenced by small variations of the initial conditions, that is proving the chaotic behavior of the measured parameters.