Methodological evaluation of method for dietary heavy metal intake.

Exposure to environmental pollutants is an important problem of environmental toxicology. Heavy metals are regarded as toxic to living organisms because of their tendency to accumulate in selected tissues. Moreover, their presence is a causative agent of various sorts of disorders, including neuro-, nephro-, carcino-, terato-, and immunological. Exposures of human to environmental chemicals can occur simultaneously from various sources. One exposure route is ingestion of hazardous chemicals through contaminated food and beverages. Considering the above-mentioned menace, efforts should be focused on the estimation of dietary intakes of potential toxic agents by consumers. Dietary exposure assessment to nonnutrients is usually performed by combining 2 sets of data-the concentration of elemental contaminants in various food products and the consumption data of these food items. A variety of approaches exist for evaluating exposure to food chemicals, and the method chosen is influenced, among others, by the intended goal, the availability of data, cost, and time frame. Moreover, it is also important to note how accurate and detailed the information concerning toxic elements intake needs to be. There are a number of sources of food consumption data currently used in exposure assessments, which range from 1 d to habitual intake. Frequently, the heavy metals for which dietary exposure is of interest are present in trace and ultra-trace quantities. Hence, an analytical technique with sufficient sensitivity is required for the accurate determination of these chemicals in food samples. It is important to remember that the accuracy of quantitative analysis is strongly dependent on the sampling and preparation steps.

Chemometrics in monitoring spatial and temporal variations in drinking water quality.

This case study reports multivariate techniques applied for the evaluation of temporal/spatial variations and interpretation of monitoring data obtained by the determination of chloro/bromo disinfection by-products in drinking water at 12 locations in the Gdansk area (Poland), over the period 1993-2000. The complex data matrix (1756 observations) was treated with various multivariate techniques. Cluster analysis (CA) was successful, yielding two different groups of similarity reflecting different types of drinking water supplied (surface and groundwater). The locations supplied in general with groundwater could be further classified into two subgroups, depending on whether the groundwater was mixed with surface water or not. Analysis of variance (ANOVA) was used to classify and thus confirm the groups found by means of cluster analysis and proved the existence of statistically significant differences between the concentration levels of CHCl3, CHBrCl2+C2HCl3, CHBr2Cl, and CH2Cl2 in the samples collected. Of all the variables evaluated, only three were characterized by statistically significant correlations (CHCl3, CHBrCl2+C2HCl3, CHBr2Cl). The analysis of correlation coefficients revealed that chloroform formed as the main chlorinated disinfection by-product and, furthermore, the natural presence of bromide in water (both ground and surface) results in the formation of brominated disinfection by-products (DBPs). Temporal variations of volatile organic chlorinated compounds (VOCls) were also evaluated by multidimensional ANOVA. Observation of temporal changes in the concentration of VOCls at the location supplied with both surface and groundwater reveals a steady improvement in drinking water quality. In general, the study shows the importance of drinking water monitoring in connection with simple but powerful statistical tools to better understand spatial and temporal variations in water quality.

Aspects of the biomonitoring studies using mosses and lichens as indicators of metal pollution.

It has been shown that mosses and lichens, in spite of all disadvantages, are good tools for air pollution monitoring, but best results could be achieved while using both of them together, because of differences in their metal uptake and retention. The researcher dealing with biomonitoring faces many difficulties; for example, in the use of lichens, those of similar composition are not easy to find, because of the differences caused by the tree on which the lichens are growing. Also, terrestrial moss is not always a good choice because of variations in its composition caused by the area it is growing on. The "bag" technique seems to be suitable in many cases because it gives the possibility of comparing wet and dry deposition and there are no differences in its content at the beginning of research. The bag construction should be made to keep the humidity of the sample stable to avoid its drying. For a complete and informative data set the biomonitor content should be compared with precipitation, particulate matter fractionation, and speciation data and also with medical statistics to evaluate the correlation between the amount of pollutants in the atmosphere and the human reaction to them.

Solid-phase extraction clean-up of soil and sediment extracts for the determination of various types of pollutants in a single run.

A new sample clean-up procedure based on solid-phase extraction (SPE) sorbents was proposed for the determination of pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in soils and sediments. The main purpose of the research was to find a combination of sorbents for the SPE method that would permit the determination of many types of analytes (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, N-, P- and Cl-containing pesticides) in a single run. Elution profiles for both the analytes and the interfering components were determined for several types of SPE sorbents (alumina, silica and surface-modified silica) and combinations of them. The efficiency of the clean-up method developed was evaluated using real soil samples.

Occurrence and determination of pesticides in natural and treated waters.

Pesticides as environmental pollutants are described in detail along with their sources and paths of entry into various elements of the environment. Comprehensive literature data on the concentration of these pollutants in natural and treated waters and wastewaters are discussed. A wide selection of isolation and preconcentration techniques for these pollutants in water is presented and discussed. An emphasis is put on solid-phase extraction. In the case of the authors' work, a more detailed description is given.

Occurrence and determination of organic pollutants in tap and surface waters of the Gdansk district.

The results of the determination of different classes of organic pollutants (trihalomethanes, polycyclic aromatic hydrocarbons (PAHs), pesticides, volatile hydrocarbons and phenols) in ground water and drinking water sampled at different sites in the Gdansk District are presented. Different methods were used to determine organic compounds in water: direct aqueous injection or sorption on solid sorbent (XAD-4) and extraction with pentane followed by a gas chromatography-electron capture detection (GC-ECD) for determination of volatile organohalogen compounds: purge and trap with a gas chromatography-flame ionization detection for determination of volatile hydrocarbons; sorption on solid sorbent XAD-4 or C18, elution with organic solvent and GC-ECD for determination of pesticides; sorption on solid sorbent C18, elution with organic solvent and a gas chromatography-mass spectrometry for determination of PAHs and sorption on solid sorbent C18, elution with organic solvent and high performance liquid chromatography-ultraviolet determination of phenols. The proposed methods have been used successfully for the determination of organic compounds in samples of tap, swimming pool, river and sea waters. The content of analysed organic compounds in the water delivered to the water supply system for Gdansk from the surface water intake in Straszyn and from other selected intakes satisfies Polish, EC and WHO standards. The surface water bodies, i.e., rivers, sea and lakes in the Gdansk District are not very polluted by anthropogenic compounds originating from municipal and industrial sewages and from agriculture.