The article describes a method of measuring engine oil wear metals by Atomic Absorption Spectrometry (AAS), which is an analytical method used to determine the concentrations of various elements in the sample. Atoms of different elements absorb different wavelengths of light in proportion to the quantities in which they are represented, as an analytical measurement property is performing absorption of radiation by free atoms of the reference element. AAS method with flame atomization allows measuring the concentration of about 60 elements of the periodic table in a solution with a sensitivity from hundredths to hundred μg.ml-1. It is used in the analysis of samples of different origins. This method makes up a significant part of monitoring low levels of toxic elements in environmental samples, which is very good to be used for its high sensitivity and selectivity. The aim of the study was the evaluation of the composition of wear particles tested oil samples by AAS, which is highly accurate and a fully automated tribotechnical diagnostics method. The intensity of each line radiation gives information about the content of investigated metals in the tested samples of motor oils, which enable us to identify not only the place from which abrasion arises, but also reveals the cause of the critical condition of the mechanism.

Wheat is worldwide consumed and contributes significantly to the intake of antioxidants with beneficial healthy effects. In the precise two-year field experiments in 2008 and 2009 two varieties of wheat einkorn, two varieties of emmer wheat and three varieties of spring wheat and in 2009 in addition two other spring wheat varieties, three einkorn varieties and three emmer wheat varieties were evaluated for selenium content and antioxidants - total polyphenols (TP). Selenium content was determined by atomic absorption spectrometry with hydride generation technique (HGAAS) and total polyphenols with Folin-Ciocalteau assay. Higher selenium content in grain is related to emmer (58.9-68.4 mu g/kg DM) and einkorn (50.0-54.8 mu g/kg DM) varieties; in spring varieties selenium content ranged from 29.8 to 39.9 mu g/kg DM. Among the varieties with high TP (expressed in gallic acid equivalents) emmer varieties prevail (584-692 mg/kg DM), less represented are einkorn (507-612 mg/kg DM) and spring wheat (502-601 mg/kg DM) varieties. Among varieties significant differences were determined. TP were significantly higher in emmer wheat varieties and one einkorn and one spring wheat variety. Between TP and Se significant linear correlation was determined (r = 0.709).

The tapeworm Moniezia expansa and naturally infected sheep were investigated with respect to their cadmium accumulation. Cadmium chloride (CdCl(2), 0.2 g) was added to 10 ml of distilled water and administered orally to the sheep every day for a period of 1 week. The cadmium content of M. expansa was lower than that in the liver tissues of sheep, although this difference was not significant. The highest mean cadmium concentrations were found in the liver of sheep infected with M. expansa (24.5+/-11.5 mgkg(-1) dry weight). The mean cadmium concentration measured in M. expansa was 21.5+/-19.2 mgkg(-1) dry weight, which was 31 and 1.5 times higher than levels determined in the muscle and kidney of the host, respectively, but 0.9 times lower than levels determined in the liver of host. Sheeps with M. expansa infection always had higher cadmium concentrations in the tissues (with the exception of the blood) than their uninfected conspecifics.

The influence of elevated cadmium content in diet on the content of this element in liver, kidney and testes of 68 male rats was studied in dependence on the chemical form of applied cadmium (as inorganic salt - CdCl2 and organically bound in yeast cells); the influence of elevated arsenic content (as NaAsO2) in diet on its content in the same organs was also investigated. The interactions between arsenic and cadmium in the above-mentioned organs were studied. The addition of cadmium to the diet of rats significantly (P < 0.05) increased cadmium content in several organs. The addition of yeast containing the natural level of Cd increased the content of cadmium in liver and kidney of experimental animals significantly (P < 0.05). A significantly (P < 0.05) increased cadmium accumulation in organs was observed after the addition of Cd as CdCl2, compared with the addition of Cd as organically bound Cd in yeast cells. At the same time, the addition of yeasts containing the natural level of Cd decreased the Cd accumulation applied as CdCl2 in the examined organs. The addition of sodium arsenite to the diet of rats led to a significantly (P < 0.05) increased arsenic content in all the analyzed organs. The addition of yeasts to the diet increased arsenic content in liver and at the same time suppressed its content in kidneys of experimental animals. The interaction between arsenic and cadmium applied simultaneously was evident. The addition of As to the diet decreased the accumulation of Cd in kidney and increased its accumulation in testes. The addition of Cd to the diet increased arsenic content in liver and kidney and decreased its content in testes.

Fermented pig slurry was used for two kinds of tomatoes fertilisation as a replacement of industrial mineral fertilisers in three-year experiment and selected elements (Pb, Cd, As, Zn and Hg) content were monitored by the AAS method. The results obtained showed that anaerobically fermented pig slurry can be a suitable alternative to mineral fertiliser use. Its use as an organic fertiliser also did not decrease the hygienic quality and safety of the grown vegetable products, and all tomato samples fulfilled the heavy metals legislation limits for Pb, Cd, As, Zn and Hg content. Statistically significant (P < 0.05) influences of the year, cultivar and fertilisation method were found in case of zinc content. No statistically significant differences in case of arsenic were discovered. Statistically significant influence (P < 0.05) of the year was found in case of cadmium and mercury contents.

The aim of the present study was to assess whether there is a difference in accumulation of heavy metal ions (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in hosts (small mammals) infected by cestode parasites when compared to those without cestode infection. The abundance of gastrointestinal parasites and bioaccumulation of heavy metals in host livers and kidneys were measured. Contents of heavy metals in hosts were determined by ICP OES method. The hosts with cestode infection (Paranoplocephala sp.) had lower contents of heavy metals in their livers and kidneys compared to hosts with nematode infection (Mastophorus muris). The content of Pb, Cd, Cr, Cu and Ni was higher in kidneys than in livers, in both (cestode and nematode infected) rodents while the content of Mn was higher in livers. Content of Zn was similar. The content of heavy metals in host was decreasing with the increasing abundance of cestodes (Paranoplocephalo sp.). Species-response models to particular heavy metals are presented.

The minerals (Al, B, Ca, Cu, Mg, Mn, Ni, Zn) of 24 authentic Czech nectar and honeydew honey samples (2003 and 2004 harvests) were determined, to find the relationship between their content and the origin or type of honey. The concentrations of analytes in the digests, obtained via optimised dry decomposition of honey samples, were measured by flame atomic absorption spectrometry (F-AAS), as well as optical emission spectrometry with inductively coupled plasma (ICP-OES). With regard to its speed of analysis and cost, ICP-OES was the more favourable method. By combining the analytical data and electrolytic conductivities of samples, the honey samples could be divided into two groups – honeydew honeys and nectar honeys. Like Slovak and Polish honeys, samples of Czech honeys had higher nickel levels than honeys originating from other parts of the world.

The effort of this work was to prove whether there exists any relation between stress factors caused by content of cadmium and zinc, and content and composition of opium alkaloids codeine, morphine, narcotine (noscapine) and papaverine contained in poppy seeds and capsules (Papaver somniferum L.) in 14 samples of 8 varieties cultivated in 8 localities in 2003. Contents of cadmium and zinc were measured by a method of electrothermic atomization and contents of selected individual alkaloids were determined by a HPLC method. The results were tested by the Spearman correlation coefficient and the pearson linear correlation coefficient. With knowledge of the Spearman coefficient, positive relations narcotine - zinc and narcotine - cadmium in the poppy seed samples were found. In the samples of poppy capsules positive relation morphine - cadmium (in cv. Opal) and negative relation papaverine - zinc and codeine - zinc ( in cv. Opal) were found. Those pairs have been tested by the Pearson correlation coefficient for a possibility to exclude the linear independency. This independency was excluded with the probability of over 95% in the relations narcotine - cadmium in the seeds and morphine - cadmium in the capsules. With the probability of over 97.5%, linear relations narcotine - zinc in seeds and papaverine - zinc in capsules were proved.

The effect of an abiotic stress caused by cadmium on the total flavonoid content in roots, shoots and leaf blades of spring barley variety Kompakt grown in a climate-control room for 28 days was investigated. Total flavonoid con tent (F) was determined spectrophotometrically with sodium nitrite, Cd content by atomic absorption spectrometry. Treatment of barley plants with Cd (1.10 –6 mol/l) in nutrition solution caused the decrease of F in the all parts of the

The effect of abiotic stress caused by cadmium on the total polyphenols content in root, shoots and leaf blades of barley was investigated in model experiments. Total polyphenols content was determined spectrophotometrically with Folin Ciocalteau's reagent, Cd content by atomic absorption spectrometry (AAS) in 28-day-old plants. Treatment of the barley plants with Cd (1.10-6 mol/l) in a nutrition solution caused the increase in the total polyphenols in all parts of the plant. The highest increase was found in the leaf blades (35.2%, 8340 mg/kg d.m.), a lesser increase found in the shoots (16.7%, 3590 mg/kg d.m.), and the lowest increase found in the roots (10.3%, 3650 mg/kg d.m.). The highest Cd increase in the treated plants was found in the roots (10 400%, 240 mg/kg d.m.), the lesser in their shoots (4990%, 16.3 mg/kg d.m.), and the lowest in the leaf blades (2580%, 5.78 mg/kg d.m.). There was found a statistically significant increase (at least P < 0.05) in the total polyphenols and Cd contents in all investigated parts of the plant. Statistically significant differences (at least P < 0.05) of the total polyphenols and Cd contents among barley roots, shoots, and leaf blades were found.

A single-purpose atomic absorption spectrometer based on in situ dry ashing followed by gold amalgamation cold vapour AAS was evaluated. Various agricultural and environmental certified reference materials (CRMs) and internal reference materials of wide range of mercury contents were analyzed and good agreement with certified values was found. Control chart of the results of mercury determination in CRM 12-02-03 (Lucerne) as well as the results of interlaboratory trials suggested that the system of mercury determination was under control. Evidently, wide spectrum of agricultural and environmental materials can be analyzed for mercury contents even at levels less than 1 mug kg(-1).

Efficiency of the different media for leaching of selected elements (Cr, Mo, Ni, Ti) from ash obtained by modified dry decomposition of plant materials in the presence of oxygen, ozone, and nitrous oxides using Dry Mode Mineralizer APION at 400 degreesC has been studied. Plant samples from IPE WEPAL interlaboratory exchange were used in the study. Data obtained for chromium, molybdenum, and nickel were evaluated by z-score classification using their contents calculated by test organizers as true values. Since the quality of Ti data given by IPE organizers is insufficient to be used for the evaluation with z-score attempt, Ti results determined after evaporation of ash with HF as total contents were used for the evaluation of the efficiency of ash dissolution. Risk of analyte losses delta by the retention in insoluble residues from decomposition of plant samples increases in the order delta(Cr) less than or equal to delta(Mo) < delta(Ni) < delta(Ti).

Goat milk has an important role in the nutrition of children who are allergic to cow milk, and also for the general population in the case of digestion problems. The anticarcinogenic effect of goat milk is also mentioned. Similarly like in other foods, the quality of goat milk is carefully checked and has to comply with general hygienic requirements. In this communication, the content of selected risk elements (heavy metals Cd, Cu, Fe, Pb, Zn) in goat milk collected from two private farms is reported. These farms differed in the concentration of animals and also in the degree of contamination from industrial sources. In addition to the above mentioned five heavy metals, the macroelements Ca, Cl and Mg were also determined in these milk samples. Bulk samples of goat milk were collected four times in 1998, regularly during the whole lactation period (April, June, August and October). For determination of Ca, Cd, Cu, Fe, Mg, Pb, and Zn in goat milk, aliquots of milk (20 g) were dried and decomposed by dry ashing. Ca, Mg and Zn were determined by the flame atomic absorption spectrometry (FAAS), Cu, Cd and Pb by electrothermal atomic absorption spectrometry (ETAAS), respectively. Fe was determined by the modified molecular spectrophotometric method after reaction with potassium thiocyanate (CSN 83 0530). Chloride ions were determined argentometrically (CSN 57 0530). In order to control the quality of analytical data, simultaneous analyses of the certified reference material CRM 063R were performed. For statistical evaluation, ANOVA method of one factor analysis of variance by the multiple comparison method and probability level of 95% was used. These results lead to the following conclusions: all average values of the determined chemical elements in milk samples from both farms are below the hygienic limits set in Regulation No. 298/1997 of the Ministry of Health of the Czech Republic. In those cases when the levels of the measured analytes are close to the regulatory limits, a higher number of parallel determinations is required. Geological composition of the given locality along with feeds seem to be more decisive for the resultant contents of contaminating chemical elements in milk than the amount of industrial and traffic emissions in the locality This can explain the relatively frequent occurrence of variable contents of the measured analytes in milk. We could not find any direct relationship between the content of the elements concerned and the time of sampling. A clearly monotonous increase was observed only in Mg content in milk from both farms during the lactation period. An analogous dependence was obtained also for Fe, but with one exception (high initial Fe content in milk from farm A). On the other hand, the amount of chloride ions in milk from farm B decreased monotonously and significantly during the lactation period. Samples from farm A showed a similar tendency. Despite of certain discrepancies it can be assumed that the levels of Ca, Cu, Zn, Cd and Pb at the beginning of the lactation period are mostly higher than those at its end. The ranges of the contents of macroelements Ca, Mg, and microelements Cd, Pb, Zn, and probably also Cu in goat milk are comparable with those commonly found in cow milk. Slightly increased levels in goat milk were observed in iron and chlorides.

A set of test materials of the green alga Chlorella vulgaris with different levels of naturally bound Cd and about the same levels of other 13 essential or trace elements (BIOMA 1–4) was produced for proficiency testing of laboratories involved in elemental analysis of food. Criteria of the laboratories’ performance, such as the z-score and combination scores RSZ and SSZ were evaluated and discussed in terms of their suitability for proficiency testing using a set of test materials with the same matrix. The use of the test materials as a set of internal reference materials has also been suggested.

Retention of selected analytes (Cd , Cr, Cu, Mn, Pb, Zn) in solid residue which remains undissolved in 1.5% HNO 3 used as a leaching medium after classical dry ashing of ten materials (alfalfa lea ves, NIST SRM 1569 Brewer' s Yeast, blood meal, meat-bone meal, feather-bone meal, silage residue , litter, pond sediment, coal waste , IRM NSC-21 Industrial Compost Vitahum) was studied . The elements remaining in the residue were determined mainly b y AAS after dissolution of this residue in the mix - ture of HF + HNO 3. In several instances, pressurized wet digestion, alkaline fusion, stripping voltammetry and instrumental neu- tron acti vation were also applied. Increasing concentr ation of mineral acid in leaching medium which does not contain HF, plus increasing final volume of the solution, suppresses significantly this type of analyte losses in the majority of matrices tested . However, for industrial compost and standard reference material NIST 1569 Br ewer' s Yeast, application of an HF step is neces - sary for quantitative release of the analytes (in particular chromium) into solution.