This study reports the valorization of pistachio shell agricultural waste, aiming to develop an eco-friendly and cost-effective biosorbent for cationic brilliant green (BG) dye adsorption from aqueous media. Pistachio shells were mercerized in an alkaline environment, resulting in the treated adsorbent (PS_NaOH). The morphological and structural features of the adsorbent were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and polarized light microscopy. The pseudo-first-order (PFO) kinetic model best described the adsorption kinetics of the BG cationic dye onto PS_NaOH biosorbents. In turn, the equilibrium data were best fitted to the Sips isotherm model. The maximum adsorption capacity decreased with temperature (from 52.42 mg/g at 300 K to 46.42 mg/g at 330 K). The isotherm parameters indicated improved affinity between the biosorbent surface and BG molecules at lower temperatures (300 K). The thermodynamic parameters estimated on the basis of the two approaches indicated a spontaneous (ΔG < 0) and exothermic (ΔH < 0) adsorption process. The design of experiments (DoE) and the response surface methodology (RSM) were employed to establish optimal conditions (sorbent dose (SD) = 4.0 g/L and initial concentration (C₀) = 10.1 mg/L), yielding removal efficiency of 98.78%. Molecular docking simulations were performed to disclose the intermolecular interactions between the BG dye and lignocellulose-based adsorbent.

The article is based on the results of the investigations carried out in the period 2020- 2023 on the microelements-metals (Ag, Al, Ba, Be, Bi, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sr, Ti, Tl, V, Zn) in the water-solid suspension system in the Prut River downstream the Costești-Stânca reservoir till the confluence with the Danube River. Water samples were filtered in situ through membrane filters with a pore diameter of 45 microns, in order to separate dissolved metals from those in solid suspensions. Inductively coupled plasma atomic emission method was used for the determination of metals, with the assistance of the ICP OES iCAP 6200 Duo spectrometer. In most cases, the lowest concentrations, especially in suspensions, were recorded in the Costești- Stânca – Braniște river section, while the highest - downstream of the confluence of the Jijia River with the Prut River. By applying the ratio of the dissolved and suspended forms of metals in the river runoff as a geochemical criterion, it was revealed that in the last years, in conditions of hydrological droughts, only Al, Mn, Ti, Tl, V, Pb, Co, and Cr predominantly migrated in suspensions in the hydrographic basin of the Prut River.

Sunt prezentate rezultatele investigațiilor privind calitatea apei din râurile mici și izvoarele din bazinul hidrografic al râului Răut, conform parametrilor fizico-chimici ai apei: temperatura, culoarea, pH-ul, conductivitatea, intensitatea mirosului, cantitatea suspensiilor minerale, organice și totale și compoziția chimică a apelor. Analizele au inclus regimul gazos, consumul biochimic (CBO5) și chimic (CCOMn și CCOCr) al oxigenului dizolvat, componența mineralizării apei, substanțele nutritive – compușii de azot și fosfor, microelementele-metale și metaloizii toxici, substanțele fenolice și petroliere, pesticidele (POPs) și alte substanțe. Au fost analizate apele din 16 afluenți ai r. Răut prin utilizarea metodelor, tehnicilor performante standardizate.

The paper includes the results of the laboratory modelling of accumulation of selenium in early ontogenesis of carp and of investigation of the accumulation of a range of trace elements in the skeletal muscles, gonads, liver, gills and skin in fish of Cyprinidae, Percidae and Esocidae families from the Dniester River.

This study is primarily focused on evaluating the chemical composition of natural water in the locality of Cișmea, situated in the Orhei district, at the coordinates 47°24’56.0"N 28°45’05.9"E. The study includes an ad-hoc analysis of two types of water: surface water and underground water. General parameters were evaluated, such as pH, conductivity, hardness, chloride and sulphate content, as well as the content of certain chemical elements. The study results highlights significant deviations from the maximum admissible concentrations (MAC) for a series of indicators, such as As, Pb, Cd, Na, and B. The determined concentrations of these elements exceed the limits allowed by the legislation of Republic of Moldova and European Union: for As by 1.7–1.9 times; Cd by 3.4–3.5 times; Pb by 1.2–2.3 times; Na by 1.2–4.0 times and B by 1.6–3.3 times. Deviations of conductivity and sulphate parameters indicate the presence of a high level of dissolved solids in the groundwater of the locality’s wells and springs. The study also signalled the presence of significant concentrations of some heavy elements, such as Ba, Tl and Bi, which are not regulated by current legislation.

The objective of the present study was to investigatethe levels of trace metals and metaloise (Fe,Zn,Al,,Sr,Ge, Be, Mn, Ba, Ga, Cu, Bi, As, Se, Ni, Te, Ti, Sb, Sn, Cr, Pb, Ag, V, Cd) in muscle ,skil,, liver, and gonade of freshwater fish, Linnaeus, 1758, from River Prut. The concentrations were different between the tissues of fish. Results showed that the microelements concentrations in difetent tissues of were prezented in descending order. Results also showed that the concentrations in the muscle and gonades of Silurus glanis are below levels of concern for human consumption.