Elisabeta Chirila

HEAVY METALS DETERMINATION IN ENVIRONMENTAL AND BIOLOGICAL SAMPLES

Heavy metals are present as elementary compounds or mineral deposits in nature, from which they are extracted and processed for different purposes. During these processes, heavy metals are released in the environment and reach the atmosphere, waters, soils, and biota (plants and animals). Heavy metals release into the environment is of great concern, due to their ability to concentrate and accumulate, in different stable forms and in different media. Quantitative determination methods and techniques are developed in order to provide valid results about the heavy metals content in different matrixes. This study presents the main analytical techniques available for heavy metals determination in environmental and biological samples, as well as an example of method validation and uncertainty estimation for Cu2+ determination in waste water samples.

Investigation of the hydration process in 3CaO·Al2O3–CaSO4 · 2H2O–plasticizer–H2O systems by X-ray diffraction

The development of the hydration process in 3CaO.Al(2)O(3)-CaSO(4) . 2H(2)O-H(2)O system is studied by X-ray diffraction in the presence of varying contents of new plasticizer admixtures belonging to the lignosulphonates class (calcium lignosuphonate-LSC) and condensates melamine formaldehyde sulfonated class-MSF (VIMC-11). The plasticizer admixtures were added in proportion of 0.1-1% solid substance. The influence of the plasticizer admixtures on the hydration process with increasing time is observed and it is shown to depend on the nature and content of the admixtures and the reaction time. The strong adsorption of admixtures on the surfaces on the anhydrous or partially hydrated particles of the system can explain the influence of the admixtures upon the kinetics of the hydration process retardation or acceleration. These plasticizer admixtures influence also the evolution of the hydrated compounds and forming of the hardening structure in the 3CaO.Al(2)O(3)-CaSO(4) . 2H(2)O-H(2)O system; their proportion in the system and the considered length of hardening are correlated. In the 3CaO.Al(2)O(3)-CaSO(4) . 2H(2)O-H(2)O system there are two different influences of the plasticizer admixtures upon the hydration process. One is a delaying action, as a result of plasticizer adsorption on the surface of the anhydrous and hydrated compound particles and another one is the intensifying action due to the stronger dispersion of the particles in aqueous medium.

Evaluation of migration behaviour of therapeutic peptide hormones in capillary electrophoresis using polybrene-coated capillaries

Modelling electrophoretic mobility as a function of pH can be simultaneously used for determination of ionization constants and for rapid selection of the optimum pH for separation of mixtures of the modelled compounds. In this work, equations describing the effect of pH on electrophoretic behaviour were used to investigate migration of a series of polyprotic amphoteric peptide hormones between pH 2 and 12 in polybrene-coated capillaries. Polybrene (hexadimethrin bromide) is a polymer composed of quaternary amines that is strongly adsorbed by the fused-silica inner surface, preventing undesired interactions between the peptides and the inner capillary wall. In polybrene-coated capillaries the separation voltage must be reversed, because of the anodic electroosmotic flow promoted by the polycationic polymer attached to the inner capillary wall. The possibility of using polybrene-coated capillaries for determination of accurate ionization constants has been evaluated and the optimum pH for separation of a mixture of the peptide hormones studied has been selected. Advantages and disadvantages of using bare fused-silica and polybrene-coated capillaries for these purposes are discussed.

POLLUTANTS EFFECTS ON HUMAN BODY – TOXICOLOGICAL APPROACH

It is a fact that any compound coming into contact with biological systems will cause some perturbations in that system. These biological responses may not be always toxicologically relevant, and from that point of view it is important to correlate information on the sources, interactions, dose and their toxicity. The interest in toxicology increased continuously in the last years with the synthesis and use of different chemicals. In the environment, humans and other leaving organisms are exposed to support the increasing number of xenobiotics: industrial chemicals, pesticides, drugs, and additives from food or beverage. The effects of some most frequently present and relevant pollutants on human body, presented as typical diseases registered at organisms’ level are presented in this paper work.

Enantioselectivity of Chiral Pesticides in the Environment

The study is aiming to present the fate of chiral pesticides, the different behaviour of these optic active isomers in the environment and their ecotoxicological effects, as well as separation techniques available for the chiral pesticides studies. We conclude that there is a tremendous need to enlarge the studies related to the enantioselective behaviour of chiral pesticides in different contaminated environmental components, as well as their ecotoxicity to biota and humans.

Analytical Approaches for Sampling and Sample Preparation for Heavy Metals Analysis in Biological Materials

Heavy metals concentrations in biological materials are necessary to be known when investigations in environmental or health risk assessment are done. The paper aims to review the modern aspects of the first step of the analytical process, sampling and sample preparation which involve some of the following operations: sample collection (sampling), washing, storage, preservation, followed by sample transformation to the most appropriate form for measurement. New separation techniques, applied for specific analytes extraction or preconcentration from biological matrices and metal speciation are also briefly described.

NATO Advanced Research Workshop on Environmental Heavy Metal Pollution and Effects on Child Mental Development: Discussion, Conclusions and Recommendations

Heavy metals can be emitted into environment by both natural and anthropogenic sources, mainly mining and industrial activity. Human exposure occurs through all environmental media. Infants are more susceptible to the adverse effects of exposure. Recently more attention is paid to the mental development of children exposed to heavy metals. The purpose of the Advanced Research Workshop was to evaluate the existing knowledge in this field, to recommend a strategy for countries and regions in risk to protect today’s children and future generations from exposure to heavy metals, and to propose the necessary coordinated studies. This paper is a draft of the findings, conclusions and recommendations, formulated as a result of the presentations of the key-speakers; of the work of two round-table discussions: one on the need for studies of the health effects of environmental pollution on children’s mental development and the second on prevention strategies; and of the finalizing working groups to summarize the output scientific value of the ARW meeting.

Chlorosis Risk Evaluation from a New Viticulture Area Located on a Former Army Region

In this work are presented original studies regarding soil characterization from a former army area, located in Nazarcea, Constantza, in order to setting out new viticulture area and to evaluate the chlorosis risk. Sodium chloride, total iron, potassium, calcium carbonate, phosphates and humus have been analyzed in soil samples by titrimetric and spectrometric methods. Physical characteristics such as pH and granulometry have been also determined. The mean of chlorotic power index (CPI), calculated for all analyzed samples show high values: 11.76 (0–20 cm depth), 73.48 (20–50 cm depth) and 108.66 (50–110 cm depth) that means high risk of chlorosis.

Contamination of Soils by Waste Deposits

The purpose of this paper is to present original results concerning concentrations of eight metals in soils adjacent to municipal waste deposits from Constanta County, Romania, during April-October 2006. The surface and depth soil solutions were obtained using aqua regia and the applied analytical technique for metal determination was flame atomic absorption spectrometry (FAAS). The mean measured values ranged as follows: Cd: 0.09-0.15 mg/kg d.w.; Co: 7.92-9.27 mg/kg d.w.; Cr: 11.37-13.86 mg/kg d.w.; Cu: 16.91-20.92 mg/kg d.w.; Mn: 379-441 mg/kg d.w.; Ni: 20.58-28.95 mg/kg d.w.; Pb: 7.24- 9.08 mg/kg d.w. and Zn: 44.28-49.93 mg/kg d.w. Except nickel all other metals concentrations have been founded below the normal limits accepted by the Romanian regulations. As a general observation, in depth soil concentrations are higher (Cr, Cu, Ni, Pb) or similar (Mn, Zn) than in surface samples (except cadmium and cobalt).

Pesticide Residues Determination in Vegetables from Romania by GC-ECD

Pesticide use raises a number of environmental concerns. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water, bottom sediments and food. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. In this study the organochlorine pesticides have been measured in vegetables samples from Dobrogea county, Romania, by gas chromatography with electron capture detector (GC-ECD) after extraction and clean-up step and also the calculated bioconcentration factor (BCFs values) were used to relate pesticide residues in plants to the pollutant concentration in soils. The pesticides concentrations were at ppb levels and BCFs values were below 1.