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The impact of dams and reservoirs on the aquatic ecosystem of rivers is a very important topic for water resource management. These hydrotechnical facilities change the natural hydromorphological regime of the rivers. This paper analyzed the hydrodynamic characteristics of an undeveloped riverbed section downstream of the Colibița reservoir, from the Bistrita Ardeleana River hydrographic basin. After processing the data obtained on the field, two hydraulic models were made using the MIKE 11 program, which aimed to identify the hydraulic parameters such as the wet section, the depth, and the water velocity. The first modeling was used for the flow rate of Q = 54.5 m3/s: the water depth was between 1.952 m and 2.559 m; and the water velocity varied between 1.148 m/s and 1.849 m/s. The second modeling was used for a flow rate of Q = 178 m3/s and showed that the water depth had values between 3.701 m and 4.427 m; and the water velocity varied between 1.316 m/s and 2.223 m/s. Following the granulometric analysis, the average diameter of the particle in the thalweg was D50 = 25.18 mm. The conclusion reached as a result of hydraulic modeling and granulometric analyses indicated that hydromorphological processes take place along the length of the analyzed sector, which have negative effects on water quality as well as on the instability of the riverbed. To make the riverbed safe along the entire studied length, we managed to identify some alternative solutions that have the role of stabilizing the banks, respectively, to stop the deepening of the thalweg. The alternative hydrotechnical constructions will increase the roughness of the riverbed, essentially reducing the water speed and increasing the favorable conditions for the retention of alluvium. [ABSTRACT FROM AUTHOR]

This paper describes a former sterile dump site that is the result of mining and ore processing. A large site located in the Baia Mare mining area (Romania) with a significant amount of Suior-type mining concentrate deposits was selected for this research. The method of analysis used in this study is inductively coupled plasma optical emission spectrometry (ICP-OES). To characterize the contaminated area, a total of 27 sterile samples and one soil sample were collected from the studied site, which was affected by the mining activity. The samples were mineralized by a mix of hydrochloric acid and nitric acid. The disaggregation of the samples took place on a sand bath, and the concentrations of nine heavy metals were determined using an inductively coupled plasma optical emission spectrometer. The investigations provided the information for a detailed analysis allowing the assessment of trace element concentrations to establish whether the area requires remediation. This paper aims to highlight the importance of obtaining quantitative analysis data when characterizing heavy metal contaminated areas that need to undergo the remediation processes, utilizing accurate and fast systems such as modern multispectral analytical devices. The objective of this paper consists of the characterization of an area in the Baia Mare municipality, Romania, affected by high heavy metal concentrations due to sterile mining material being deposited on its surface in order to determine if the area requires remediation. [ABSTRACT FROM AUTHOR]

The current study was conducted to assess the level and spatial distribution of metal pollution in surface water, soil, and sediment samples from the Arieș River basin, located in central Romania, an area impacted by various mining and industrial operations. Several pollution indices, spatial distributions, cluster analyses, principal component analyses, and heat maps were applied for evaluating the contamination level with Ni, Cu, Zn, Cd, Pb, Mn, As, and Hg in the area. Based on the results of the Heavy-Metal Pollution Index and of the Heavy-Metal Evaluation Index of the surface-water samples, the middle part of the Arieș River basin, near and downstream of the gold mine impoundment, was characterized by high pollution levels. The metal concentration was higher near the tailing impoundment, with increased levels of Cu, Ni, Zn, and Pb in the soil samples and As, Cd, Pb, Na, K, Ca, Mn, and Al in the sediment samples. Ca (23.7–219 mg/L), Mg (2.55–18.30 mg/L), K (0.64–14.70 mg/L), Al (0.06–22.80 mg/L), and Mn (0.03–22.40 mg/L) had the most remarkable spatial variation among the surface-water samples, while various metal contents fluctuated strongly among the sampling locations. Al varied from 743 to 19.8 mg/kg, Fe from 529 to 11.4 mg/kg, Ca from 2316 to 11.8 mg/kg, and Mg from 967 to 2547 mg/kg in the soil samples, and Al varied from 3106 to 8022 mg/kg, Fe from 314 to 5982 mg/kg, Ca from 1367 to 8308 mg/kg, and Mg from 412 to 1913 mg/kg in the sediment samples. The Potential Ecological Risk Index values for soil and sediments were in the orders Cu > Ni > Pb > Hg > Cr > As > Mn > Zn > Cd and As > Cu > Cr > Cd > Pb > Ni > Hg > Mn > Zn, respectively, and the highest values were found around the gold mine impoundment. [ABSTRACT FROM AUTHOR]

Industrial activities in the Baia Mare, Romania area have generated strong pollution, and the impact on soil quality in the neighboring areas of the city remains unclear. The aim of the research is to investigate samples of soil from Baia Mare in order to determine the quality of the soil and also the ecological risk of the soil. This study presents among the first studies using the ecological risk assessment methodology on the soil from the Baia Mare area and aims to serve as scientific support for future studies and research. Evaluation of the soil quality state was performed by determining the physical-chemical characteristics of the soil (pH, texture, structure, and concentration of metals). Evaluation of the anthropic activity from the studied areas was conducted by determining the pollution indices: Cf; Cd, PLI, Er, and PERI. The results of this study indicate that the surface soils have very high concentrations of metals (Cd: 3.5–14.4 mg kg−1; Cu: 9.4–361.5 mg kg−1; Pb: 29.7–1973 mg kg−1), with exceedances of the limit values established in the Romanian legislation. Results regarding the degree of contamination, the PLI pollution load index (1.3–14.9), and the PERI potential ecological risk index (733.9–4686) indicate that soils in the studied area have a very high degree of pollution. [ABSTRACT FROM AUTHOR]

The feasibility of using Robinia pseudoacacia in phytoremediation of sterile dumps was determined. The potential of Robinia pseudoacacia seeds to grow in a medium contaminated with high concentrations of Pb, Cd, and Cu was firstly evaluated by applying germination tests on acacia seeds in the presence of various extractants prepared by mixtures of sterile material (SM) collected from the "Radeș" dump (Romania), calcium carbonate (CaCO3) and dehydrated sludge (DS) from Someș Water Treatment Plant (Cluj Napoca, Romania), fertilizer (N.P.K.), and potassium monobasic phosphate (KH2PO4-99.5%). The results indicated that Robinia pseudoacacia seeds grow much better in an acidic than in a neutral medium and in the absence of carbonates. The capacity of metal uptake from SM by Robinia pseudoacacia and the development of the plants were then investigated at the laboratory scale. During the phytoremediation process, 92.31% of Cu was removed from SM, and the development of the Robinia pseudoacacia plants was favorable. However, although the results of the present study indicated that Robinia pseudoacacia can be successfully used in the phytoremediation of sterile dumps, making a sustainable decision for the current situation of sterile dumps located in mining areas may be difficult because an optimal point between people, profit, planet, and diverse ethical views must be found. [ABSTRACT FROM AUTHOR]

The soil samples were taken from the site of a former oil products depot from an industrial area (Romania). The soil samples taken were analyzed from a physical and chemical point of view: texture, pH, soil micronutrient content, metals concentration and petroleum hydrocarbon concentration (PHCs). The soil contaminated with total petroleum hydrocarbon (TPH (4280 mg kg−1) was disposed in the form of a pile (L × W × H: 3000 × 1400 × 500 mm). Experiments on a pilot-scale were conducted over 12 weeks at constant pH (7.5–8), temperature (22–32 °C), nutrient contents C/N/P ratio 100/10/1, soil aeration time (8 h/day) and moisture (30%). Samples were taken every two weeks for the monitoring of the TPH and the microorganisms content. During the experiment, microorganisms were added (Pseudomonas and Bacillus) every two weeks. Results of the analyses regarding the concentration of PHCs were revealed a linear decrease of the concentration of PHCs after only two weeks of treatment. This decrease in concentration was also achieved in the following weeks. Following the analysis performed on the model at the pilot scale regarding the depollution process, it can be concluded that a soil contaminated with petroleum hydrocarbons can be efficiently depolluted by performing an aeration of 8 h/day, adding microorganisms Pseudomonas and Bacillus to ensure the conditions for increasing in the total number of germs (colony forming units–CFU) from 151 × 105 to 213 × 107 CFU g−1 soil, after 12 weeks of soil treatment—the depollution efficiency achieved is 83%. [ABSTRACT FROM AUTHOR]