Cadmium exposure pathways in the Czech urban population.

The article describes the exposure pathways of cadmium in the Czech urban population. The data on Cd concentrations originated from the Environmental Health Monitoring System, which has been realized in 30 cities since 1994. The data on cadmium content in particular exposure pathways - diet, drinking water, ambient air and soil -were processed for the period 1994-2003. The estimate of the daily dietary intake for an average adult population amounted to 11-19 microg/d, i.e. 0.17-0.30 microg/kg bw/d, which represents 17%-30% of the PTWI (provisional tolerable weekly intake). The contribution from drinking water to the oral exposure is low; on average 0.5 microg/d. Potential exposure to airborne Cd was estimated at about 0.02 microg/d. The additional Cd intake from urban soil ingestion probable in small children was found to be insignificant based on Cd concentrations in the soil of kindergarten playgrounds. Biomonitoring outputs characterize the recent and life-long cadmium burden of the Czech population from general environment In 1994-2003, the median blood Cd levels ranged in the interval 0.9-0.4 microg/l blood, in smokers being more than double that in non-smokers. Blood Cd levels detected indicate slightly decreasing trend as well as urine Cd levels (range of median values 0.44-0.28 microg/g creatinine). Since 1996 the levels in children have been found in more than 50% cases below the detection limit of the methods used. The estimated total cadmium intake in the Czech urban population does not signalize any increased risk of health impairment considering non-carcinogenic effects.

Establishing a food list for a Total Diet Study: how does food consumption of specific subpopulations need to be considered?

A Total Diet Study (TDS) consists of selecting, collecting and analysing commonly consumed foods to obtain concentration data of different chemical compounds in foods as eaten. A TDS food list summarises the most consumed foods and represents the dietary habits of the general population of the country under study. The work reported here investigated whether TDS food lists that were initially designed for the whole population of the country under study also sufficiently cover the dietary pattern of specific subpopulations that are extra vulnerable for certain contaminants. The work was performed using data of three European countries: the Czech Republic, France and the UK. Each national food consumption database was combined with the corresponding national TDS food list (containing 336, 212 and 119 food items for the Czech Republic, France and the UK, respectively). The data were aggregated on the highest level of hierarchy of FoodEx-1, a pan-European food classification system, including 20 main FoodEx-1 groups. For the group 'milk and dairy products', the coverage of the consumption by the food list was investigated for more refined subgroups. For each food group or subgroup and country, the average percentage of coverage of the diet by the national TDS food list was calculated for different subpopulations, including children versus adults, women versus men, vegetarians versus non-vegetarians, and women of child-bearing age versus older women. The average diet of the different subpopulations was sufficiently covered by the food list of the Czech Republic and France. For the UK the average coverage was low due to a different food-coding approach and because food lists were not derived directly from national food consumption data. At the level of the 20 main food groups, differences between the subpopulations with respect to the average coverage of consumption by the TDS food list were minimal. The differences were more pronounced when looking in detail at the coverage of the dairy consumption. TDS food lists based on the mean consumption of the general population are also applicable to study the chemical exposure of different subpopulations, e.g. children, women of child-bearing age and vegetarians. This lowers the effort when performing a TDS.

Exposure assessment within a Total Diet Study: a comparison of the use of the pan-European classification system FoodEx-1 with national food classification systems.

A Total Diet Study (TDS) consists of selecting, collecting and preparing commonly consumed foods purchased at retail level and analysing them for harmful and/or beneficial chemical substances. A food classification system is needed to link food consumption data with the contaminant concentration data obtained in the TDS for the exposure assessment. In this study a comparison was made between the use of a national food classification systems and the use of FoodEx-1, developed and recommended by the European Food Safety Authority (EFSA). The work was performed using data of six European countries: Belgium, Czech Republic, France, The Netherlands, Spain and the UK. For each population, exposure to contaminant A (organic compounds) and/or contaminant B (inorganic compound) was assessed by the Monte Carlo Risk Assessment (MCRA) software using the national classification system and FoodEx-1 for food consumption data and for TDS laboratory results. Minimal differences between both approaches were observed. This observation applied for both contaminant A and contaminant B. In general risk assessment will be similar for both approaches; however, this is not guaranteed. FoodEx-1 proved to be a valuable hierarchic classification system in order to harmonise exposure assessment based on existing TDS results throughout Europe.

Application of a chromogenic medium and the PCR method for the rapid confirmation of L. monocytogenes in foodstuffs.

Detection of Listeria monocytogenes in foodstuffs by conventional cultivation methods carried out according to EN ISO guidelines is rather time-consuming. Therefore, two alternative methods were applied for rapid confirmation of L. monocytogenes in foodstuffs. Inoculum from liquid selective broth was plated on PALCAM and OXFORD agar and on chromogenic agar medium RAPID L. mono. Suspect colonies from PALCAM were confirmed according to EN ISO standards and by the multiplex PCR method. In total, 990 samples of foodstuffs were investigated and 63 strains of L. monocytogenes were isolated. The chromogenic medium RAPID L. mono provided results comparable to PCR, it is easier to handle and provides considerable financial savings.

Operationalization of food consumption surveys in Europe: recommendations from the European Food Consumption Survey Methods (EFCOSUM) Project.

BACKGROUND: The EFCOSUM (European Food Consumption Survey Methods) Project aims at harmonizing food consumption surveys in European countries within the perspective of an overall Public Health Monitoring Programme. Harmonization implies the need for a common framework of procedures and tools, that are applicable and feasible in all potentially interested countries. A major element in such a framework is the protocol for the operationalization of a food consumption survey, referring to all practical, logistical and material conditions that need to be fulfilled in order to guarantee a successful implementation of such a survey. OBJECTIVE: The objective of this paper was to review a number of aspects of operationalization of food consumption surveys in detail. On the basis of the currently available knowledge and experience in Europe, consensus recommendations have been elaborated for an operationalization protocol that would be feasible for all European countries. METHODS: The EFCOSUM recommendations with respect to operationalization of food consumption surveys in Europe are mainly based on three sources of information, which have been discussed at several ad hoc expert meetings: experience from previous collaborative epidemiological studies, literature searches and results of two questionnaires, distributed among representatives from 23 European countries-all experts affiliated with experienced organizations in the fields of nutrition research and related fields. RESULTS: Consensus recommendations have been set up for the following topics: sampling, recruitment, fieldwork, biomarkers, interviewer qualifications and training and quality control. These recommendations have to be considered the best achievable common denominator within Europe at this time. In a number of cases, recommendations are presented in a hierarchical way, with a gradation from first choice options towards acceptable alternatives. CONCLUSIONS: It can be concluded that a high degree of standardization of fieldwork can be achieved within Europe. A number of specific problems and constraints will have to be solved in connection with the conduction of a real survey. These problems include, amongst others, country-specific decisions on, for example, target population, detailed sampling and recruiting procedures, interview setting and support. However, on the whole, these problems can be overcome and the main recommendations presented in this paper are considered feasible for every country in Europe. Application of the EFCOSUM operationalization protocol in European countries will contribute significantly to the quality and comparability of food consumption data across Europe. It is anticipated that the policy supporting and orienting potential of this type of databases-both at the national and at the EU supranational level-will be increased accordingly.

Study of human exposure to ochratoxin A and assessment of possible sources.

The first study carried out in the CSFR covered 644 samples of blood sera from the district of Uherské Hradiste (about 1,000 km2 and 150,000 population) during March-May 1990. The samples from the selected persons (over 18 years of age) were collected within 4 sampling weeks. Ochratoxin A (OA) was established densitometrically after the minicolumn separation with HPTLC. The detection limit was about 0.5 microgram OA/l, recovery about 95%. The maximum established value was 12 micrograms OA/l. The value 1 microgram OA/l was exceeded by 12.4% of samples. Seventy-eight per cent of samples were under the detection limit. After stratification of the experimental group (according to sex and age) higher numbers of findings above 1 microgram OA/l were found in the stratum of 30-40 years (males and females) and in the age group over 60 (females). The differences were statistically insignificant (contingency table analysis, alpha > 0.10). The high statistical significance (contingency table analysis) of difference (alpha < 0.01) showed the findings over 1 microgram OA/l, and the date of the sampling week. The graphic analysis (localisation of the results in the map of the area) did not support the hypothesis of the dependence of the results over 1 microgram OA/l on the place of residence. The results do not support the hypothesis on the sites with a higher level of OA contamination in the studied district. We assume the OA hazard sources originating from both the individual and communal food supply.

Health risk assessment of the mycotoxin ochratoxin A to humans: Czech Republic--Brno--1991/92.

In the course of year 1991 and 1992 about 594 blood donors of the Brno agglomeration in the Czech Republic were examined for the ochratoxin A content (OA) in blood serum. When higher concentrations of OA were found the blood donors were examined repeatedly (differentiation of acute or chronic exposure). A mean concentration of 0.63 microgram OA/l blood serum (0.30 microgram = geom.mean) was recorded. The assessed continuous mean daily dietary intake of OA was about 0.74 ng (0.35 ng = geom. mean) OA/kg b.w./day. The assessed continuous mean contamination of food groups (cereal and meat products) was about 0.65 microgram (0.31 microgram = geom. mean) OA/kg. In persons with elevated OA concentrations in blood serum the decrease was at the latest confirmed within 2 months after the test result. An accidental acute exposure was probably involved. Tolerable daily intake of OA (TDI) was determined with regard to the nephrotoxic, teratogenic, immunosuppressive and carcinogenic effect at the level of: 16,500, 250 and 5 ng OA/kg b.w./day. As a legislative limit TDI = 5 ng OA/kg b.w./day was suggested. The group of persons studied was probably not threatened by any of the health risks given.

Determination of the mycotoxin deoxynivalenol in beer by commercial elisa tests and estimation of the exposure dose from beer for the population in the Czech Republic.

About 150 litres of beer per person is consumed yearly in the Czech Republic. It is one of the highest consumptions in international comparison. Thus, beer can be a significant source of exposure of man to some contaminants. Among natural contaminants of beer belongs also deoxynivalenol (DON). 77 samples of beer being sold in the shopping network in the Czech Republic were examined by means of commercial ELISA sets for determination of deoxynivalenol (RIDASCREEN DON) at the end of the year 1994 and at the beginning of the year 1995. 23% of the beer samples were under a detection limit of the ELISA test (6 mu g of DON/litre). The other samples contained DON in amount of 7-70 mu g/litre. The median came up to 12.6 mu g of DON/litre. By variance analysis, statistically conclusive (P = 0.01) lower concentrations of DON were found in 11-12% light beer in comparison with 10% light beer and other beer. On the basis of results, the average exposure of beer consumers in the Czech Republic was estimated at a level of 0.146 mu g of DON/kg of b.w./day. The calculation was based on a geometric mean of DON concentrations and on an average corrected consumption of individual kinds of beer. This exposure represents about 11.7% of the proposed TDI (1.25 mu g of DON/kg of b.w./day, determined from the view of the immunosuppression effect of DON). The detected exposure to DON from beer does not represent a serious health risk for a consumer in the Czech Republic. In calculations of the total exposure dose of DON for man from cereal sources is it, however, appropriate to include also beer.

Determination of the mycotoxin fumonisins in gluten-free diet (corn-based commodities) in the Czech Republic.

The fumonisins, mycotoxins produced by Fusarium moniliforme, are known to occur worldwide as natural contaminants of corn. They are associated with several animal diseases and are a potential threat to human health. A total of 127 samples of corn-based foods (gluten-free diet) in the Czech Republic were analysed by Ridascreen Fumonisin Fast ELISA methods in years 1995-1996. Eighty eight % of the corn-based foods were found to be positive for fumonisins (FB1, FB2, FB3) and 12% of the examined corn-based foods laid below of a determination limit which was about 9 ng fumonisins/g corn-based foods. The highest fumonisin contamination levels were recorded in extruded corn products containing up to 1,808 micrograms/kg of fumonisins. Levels ranging from < 9 to 1,243 ng/g fumonisins were detected in polenta. Lower levels of fumonisins were found in other commodities, such as corn flour (up to 487 ng/g), corn instant porridge (up to 788 ng/g), and corn pastes (511 ng/g). Intake of fumonisins from several corn-based foods (gluten-free diet) for the population with coeliac disease was estimated. The highest estimate of exposure dose of fumonisins was determined from corn-extruded bread: 3.2 micrograms/person/day (mean of measured values). Daily intake of fumonisins from polenta is expected 2.8 micrograms/person/day (mean). The lower exposure dose of fumonisins we can expect from corn instant porridge, corn postes and other corn products--corn and amaranth biscuit, corn beverage: 0.9, 1.1 and 0.3 micrograms/person/day (mean) respectively.

Determination of n-methylcarbamates in foods.

The multiresidue method using multisolvent extraction, SPE cleanup of the extract, HPLC with the use of OPA post-column reaction and fluorescence detection for the determination of N-methylcarbamate pesticides in food products was used. A matrix solid phase dispersion method of the isolation and extraction of carbamates was alternatively applied. In the introductory study 44 items of the food basket for the Czech Republic were analysed. In the major part of the studied samples, the considerable part of which was culinary treated, the concentration of the target carbamates was below the limit of the used detection method. In the concentration range of 10-100 microg/kg in the analysed samples of the studied analytes, aldicarb and its metabolites, e.g. methomyl and methiocarb were being found most frequently.

Dietary guidelines in the Czech Republic III.: Challenge for the 3rd millennium.

In developed countries, dietary guidelines are more and more often used as a source of binding information not only in public health, food production, nutrition and agricultural policy, but in ecology and economy as well. In view of that, it is imperative to formulate such guidelines that would be supported by relevant population studies and correspond to the European model of WHO/CINDI guidelines. At the turn of the millennium, the Czech guidelines were updated in order that serving sizes of 5 basic food groups were brought closer to contemporary trends emphasizing lower protein intakes and at the same time, by setting limit ranges, they were able to meet specific need of people of different age group, sex, physiological status, physical activity, etc. The conversion of recommended servings to nutrients was compared with the results of the actual food basket of the Czech population and specific recommendations for amendments in proportions of individual food items in food groups and subgroups were given. On the basis of diet guidelines, conclusions describing tasks for the beginning of the third millennium were made. Besides them the most important are: production or health information systems with special emphasis to food intake and nutritional status report, policies to increase the access to vegetables and fruit for vulnerable groups, legislation to curb advertising high-fat energy-dense foods to children, policy to strengthen the operational targets of Innocenti Declaration and to increase the number of Baby Friendly Hospitals, legislation regarding food control systems based on international standards, sustainable campaigns to promote safe healthy diet, policies to ensure sustainable food production.

Five years of the system of monitoring the environmental impact on population health of the Czech Republic.

The data collected in the System of monitoring the environmental impact on population health of the Czech Republic in 1994-1998 were obtained routinely and in a stabilized manner in six subsystems: health consequences and risks related to air pollution, drinking water quality, noise, human dietary exposure, human exposure to toxic pollutants from the environment and monitoring of the health status and evaluation of selected indicators of demographic and health statistics. They represent a useful and comprehensive background for providing objective information on the health status of the Czech population and on pollution of different components of the environment in the Czech Republic. The results obtained in the period 1994-1998 show that no critical situation needing urgent countermeasures to be taken appeared in the localities monitored. However, some results are indicative of the necessity to take certain remedial measures to maintain all population exposure burdens as low as reasonably possible from the economical and social points of view. Generally, the admissible limit values and exposure limits are exceeded only sporadically in some localities while for most contaminants monitored only very low values compared to the limits can be found and such situations are mostly considered as non-systematic changes.

System of monitoring the environmental impact on population health of the Czech Republic.

The data collected in the System of monitoring the environmental impact on population health of the Czech Republic in 1994 and 1995 were obtained routinely and in a stabilized manner in six subsystems: health consequences and risks related to air pollution, drinking water quality, noise, human dietary exposure, human exposure to toxic pollutants from the environment and the monitoring of the health state and evaluation of selected indicators of demographic and health statistics. They represent a useful and comprehensive background for providing objective information on the health status of the Czech population and on pollution of different components of the environment in the Czech Republic to other countries in Europe and worldwide to facilitate their commercial and cultural contacts. The results of the calendar year 1995 show that no critical situation needing urgent countermeasures to be taken appeared in the localities monitored. However, some results are indicative of the necessity to take certain remedial measures to maintain all population exposure burdens as low as reasonably possible from the economical and social points of view. The set of problems was identified as important also in 1994. Generally, the limit values and exposure standards are exceeded only sporadically in some localities while for most contaminants monitored only very low values compared to the admissible limits can be found.

Copper saturation pathways of the urban population in the Czech Republic.

The estimation of the copper saturation pathways of the Czech urban population is presented. The data on copper concentrations proceed from the System of monitoring the environmental impact on population health in the Czech Republic in the period 1994-1998. The copper concentrations were monitored in foodstuffs from the commercial network, in drinking water at the outlets of the waterworks and in the public water main networks, and in the ambient air. The copper levels were measured also in biological material to obtain the data on the copper saturation of the population under monitoring. The copper intake from foodstuffs and drinking water did not vary significantly either in the particular years of monitoring or individual cities. The same concerns also the copper levels in biological material. The total copper intake for an average adult was estimated to be 20.2 micrograms/kg b.w./d., i.e. 1300 micrograms/d. Over 99% of the total intake was that from the diet. The exposure from the intake of drinking water as well as from ambient air was low. The total daily intake lies in the interval 1000-2000 micrograms/d which is usually found in the similar studies of the copper intake. It represents only 40% of the daily dietary copper intake recommended by the JECFA FAO/WHO Commission, 1982. The copper levels in biological material did not differ from the reference values, and did not indicate any evincible hyposaturation of the population with copper.

[Preparation and identification of aflatoxin B2a under laboratory conditions]. / Príprava a identifikace aflatoxinu B2a v laboratorních podmínkách.

The method of preparing and identifying small quantities of aflatoxin B2a after Pohland et al. (1968) was verified as it was necessary to differentiate various types of aflatoxins in analytic practice. Aflatoxin B2a was prepared by the hydroxylation of aflatoxin B1 in acid medium and was identified by thin silica gel layer chromatography (TLC) and by spectral analysis in methanol medium and in a mixture of methanol with ammonium hydroxide (14 + 1). The results of both methods of identification were in keeping with the results of earlier works. At TLC in the system of chloroform + methanol (95 + 5) the Rf values were as follows: Rf AFB1--0.68 and Rf AFB2a--0.32; in the system of chloroform + acetone + isopropyl alcohol (85 + 10 + 5) the respective values were Rf AFB1--0.46 and Rf AFB2a--0.22. Spectral analysis demonstrated a shift in the absorption maximum in the methanol + ammonium hydroxide medium from 362 nm to 404 nm in aflatoxin B2a. The yield rate of AFB2a was about 50 to 55%.

[Immunoenzyme detection of the mycotoxin, ochratoxin A]. / Enzymoimunologické stanovení mykotoxinu ochratoxin A.

Indirect, enzymoimmunological assays of the mycotoxin ochratoxin A were developed. In this technique a polyclonal (rabbit) antibody to ochratoxin A was used, along with the other, peroxidase-labelled (pig anti rabbit) antibody. The sensitivity of this method ranged around 75 pg of ochratoxin A per pit. The range of calibration curve was from 10 to 1000 pg per pit. The cross reactions with other ochratoxins made 1.4% (ochratoxin C). The ELISA test of ochratoxin A can be used as an expeditious screening method for a preliminary examination of the greater number of samples.

[Preparation of the mycotoxin ochratoxin A for research and diagnostic purposes]. / Príprava mykotoxinu ochratoxin A k výzkumným a diagnostickým úcelum.

The following fungal strains were tested for the production of the mycotoxin ochratoxin A: Aspergillus melleus (CCM F 802), Aspergillus ochraceus (CCM 8002) and Aspergillus ochraceus (CCM F 803). The strain Aspergillus melleus (CCM F 802) proved to be very suitable for the laboratory preparation of ochratoxin A. The mould was multiplied on a natural substrate for 14 days at the temperature of 28 degrees C and at 100% relative humidity. Ochratoxin A was extracted into organic solvents (chloroform + acetic acid), purified with aqueous alkaline solutions and by preparative thin-layer chromatography. The isolated mycotoxin was identified by physico-chemical methods. The amount of pure ochratoxin A isolated from 600 g of substrate was 305 mg.

[Aflatoxin M1 - isolation of a toxin-producing strain of the mold Aspergillus flavus]. / Aflatoxin M1 - záchyt produkcního kmene plísne Aspergillus flavus.

A strain of Aspergillus flavus producing aflatoxins B1, G1 and M1 was obtained. Aflatoxin M1 constitutes about 5% of the total amount of aflatoxins produced. Aflatoxin M1 was isolated from a crude chloroform extract and was identified by thin silica-gel layer chromatography (TLC), by high-performance liquid chromatography (HPLC) and spectral analysis.

[The effect of polychlorinated biphenyls (PCB) on chickens: the effect of long-term administration of medium doses of Delor 103 on the levels of thyroxine, triiodothyronine and total calcium in the blood serum]. / Ucinek polychlorovaných bifenylu (PCB) na organismus kurat: vliv dlouhodobého príjmu stredních dávek Deloru 103 na koncentraci thyroxinu, trijódthyroninu a celkového vápníku v krevním séru.

A trial with the continual administration of feed contaminated with the Delor 103 preparation (polychlorinated biphenyls--PCB) at a rate of 75 mg per kg for chicks lasted four weeks. The concentrations of serum thyroxine and triiodothyronine were found to decrease, the concentrations of total calcium increased and at the Delor 103 doses of 150 mg per kg even the phosphorus concentration and the activity of alkaline phosphatase in the serum of chicks decreased. The addition of potassium iodide to feed (250 mg per kg) did not influence the clinical picture of Delor 103 intoxication. The results confirm a finding that in the course of PCB intoxication severe disorders of the thyroid gland take place and calcium metabolism is disturbed. This finding is important in view of evaluation of the intoxication of young, growing chicks.

[The effect of the preparation Kurasan (ethoxyquin) on the toxigenic properties of the mold Aspergillus flavus]. / Ucinek prípravku Kurasan (ethoxyquin) na toxinogenní vlastnosti plísne Aspergillus flavus.

The effects of Kurasan antioxidant (min. 78% ethoxyquin) were studied on toxin formation of the fungus Aspergillus flavus (strain AF 1982/M1). Aflatoxins mostly of type B1, G1, M1 are produced by the mentioned fungal strain. The strain was cultivated for seven days at high relative humidity on a substrate mostly of cereals (Karlovarské suchary--Carlsbad rusks). Application of 25 mg Kurasan per 1 kg substrate reduced type G1 aflatoxin formation by 90%. The total production of aflatoxins decreased expressively (by 50-60% after addition of 100-200 mg Kurasan per 1 kg substrate). It was only at high amounts of Kurasan that B1 and M1 aflatoxin formation was inhibited and it was correlated. Positive effects of Kurasan antioxidant applied to feed mixtures were demonstrated--aflatoxin formation by toxicogenic fungi is inhibited.