Cristina Dinu

The Influence of the Air-Drying Pretreatment of Sediment Samples for Metallic Element Mobilities

Chemical analysis of sediments provides an efficient tool for water quality management. Ten sediment samples collected in 2008 from two locations situated in the Danube Delta Biosphere were analyzed in a comparative study of mobile metallic elements via two different pre-treatment techniques: air-drying followed by sieving and wet sieving. The experimental data proved that air-drying procedure produces drastic changes in mobility of the metallic elements from the sediments which were studied as an effect of the oxidizing conditions. Wet sediment or oxygen-free dried sediment is recommended to be used in environmental studies regarding determination of mobile fractions from sediment samples.

IDENTIFICATION AND ANALYSIS OF BIOPOLYMERS FROM CRUSTACEANS DECAPOD OF THE ROMANIAN BLACK SEA WATERS

The using of marine resources for the industrial, biomedical applications and human consumption has got a quickly growth in previous decade in the world. The Romanian Black Sea environment, containing lots of organisms, which have considerable ecological and biological properties, is one of the most unstudied biological resources. In this paper, we have identified three species of crustaceans on Romanian sea waters of the Black Sea, as possible sources of chitin and chitosan. Because these species constitute a rich source of value-added products, as chitin, protein pigments and flavour componds, the full exploitation of this easily accesible resource has attracted much interest. Chitin and chitosan, the naturally renewable polymers have excellent properties such as biodegradability, biocompatibility, non-toxicity and adsorption. The extraction and characterization of these biopolymers have been studied by optical microscopy and FTIR/ATR spectroscopy. Results of the preliminary studies revealed from: FTIR/ATR „fingerprint spectra”, intensities and stretching, characteristic functional groups of bands, the presence of chitin and chitosan in the samples. Spectra samples were compared with those of chitin and chitosan standards. By optical microscopy and FTIR/ATR coupled analytical methods the results have been checked and also, indicated morphological differences between the chitin and chitosan standards. The material (crustacean shell) was dried, milled and sieved (dimensions of the particles less than 150 μm) and than digested in a mixture of peroxide, nitric acid and hydrochloric acid. Metallic elements, such as As, Cd, Cr, Cu, Fe, Mo, Ni, Pb, Se, Zn, V, Al, Ca, Mg, Na, K, were analyzed using inductively coupled plama optical emission spectrometry. High contents of Ca, Mg, Na and K were recorded.

Evaluation of Drinking Water Quality in Three Municipalities of Romania: The Influence of Municipal and Customer's Distribution Systems Concerning Trace Metals

When drinking water is distributed through pipelines, biofilms will grow on the inner surface of the pipes and soft deposits (organic and inorganic matter) and several metals will accumulate to the pipelines (Lehtola & al, 2004a). Discoloration of drinking water is one of the main reasons customers complain to their water company. An elevated concentration of iron or increased turbidity, affect taste, odor and color in drinking water. Unlined iron pipes in drinking water distribution networks develop extensive internal corrosion scales as the time of use increases. These corrosion scale deposits reduce the hydraulic capacity of the pipes and more energy is required to deliver water at a desire flow rate (Sarin et al., 2004).