This work aims at assessing the pollution degree of the Olt River (Romania), based on the Canadian Water Quality (CWQI) index, by monitoring twenty twos locations along the middle and south part of the river basin for a period of four months, from March to October, during 2018. A comprehensive physico-chemical analysis involving major cations (Ca2+, Mg2+, Na+), anions (Cl-, SO42-, N-NO3--) and general parameters (pH, electrical conductivity, total dissolve solids) was performed for this purpose. Results demonstrated that CWQI values classified the water in the investigated sectors of the river as fair (values ​​between 66.08 to 79.05), marginal (56.22 to 64.63) and good (value of 85.60). This method appears to be more systematic and provide comparative evaluation of the water quality in different seasons of the year. The results showed that there is a large variations in the parameters in different sections of the river due to different anthropogenic factors. Therefore, this index may be helpful as marker for the public to better understand the quality of water, but also as tool for water quality management.

Article info:Results obtained for proficiency tests during 2000-2017 period are used to verify and validate measurements method of tritium specific activity in aqueous samples. The longterm uncertainty method (LTUM) was applied to Tritium Laboratory results in order to identify the constant and proportional bias effects, stability of the laboratory routine procedure, and total error of the measurements.

Dyes are intensively used in industries such as textiles, plastics, cosmetics, etc., and they are considered major wastes. Due to their chemical structures, dyes are resistant on exposure to sun or water, therefore being difficult to be removed once released into the aquatic environment, having serious environmental impact. Among these dyes, rhodamine is a fluorescent dye. The mesoporous SBA-16 nanosilica has been synthesized by sol−gel process. The rhodamine 110 adsorption process on SBA-16 was explained by Langmuir and Henry isotherm models. The excellent adsorption and fluorescence properties reduction indicated that the mesoporous silica can be efficiently applied in the wastewater treatment.

Mining activities, in combination with accelerated urbanization growth and climate change, constitutes a major challenge for creating a sustainable development. Thus, the monitoring and assessment of mining effect is mandatory in understanding the impact on the primary physico-chemical characteristics of an environment. In this context, the paper presents the evolution of micro- and macro- nutrients in water, soil and sediment from two industrial areas from Romania (Copșa Mică industrial platform and Baia Sprie mining zone), in order to assess the impact of pollutants on ecosystems. Physico-chemical (pH, NH4+, NO3-, NO2-, TN, TP), base cations (Ca, Mg, Na and K) and micronutrients (Fe, Mn and Zn) have been analyzed in order to evaluate the quality of the environment. For some of the analyzed soils, the concentration of Zn, Mn and Fe exceeded the maximum permissible limits (MPL) imposed by the Romanian legislation, falling within the limit for Alert Thresholds for less sensitive soils. The correlation analysis on water quality parameters revealed that all parameters are more or less correlated with each other Person’s Correlation matrix. Overall, our results demonstrated that the knowledge of the physico-chemical regime of an environment is of great value in the determination of its productivity, usefulness and other characteristics which can facilitate further vegetation restoration and reconstruction and a sustainable development of the ecological environment in a polluted area.

Hydrochemical investigations of the surface water and the seasonal effect on the chemical budget of ions from the Olt river were carried out. Geochemical results show that the seasonal effect does not change the order of ion abundance. The Piper diagram was used for the classification of cations and anions, in terms of confidence in the major percentages of ions and types of water. According to the Piper diagram, the dominant hydrochemical facies in the study area is Ca-Na-HCO 3 − -Cl − , which represents 87% of the samples. The study area is influenced by natural processes of water-rock interaction such as dissolution of evaporitic rocks (gypsum, anhydrite, and halite).