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.

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.

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.

Effect of tissue factor deficiency on mouse and tumor development.

Previous reports suggest that tissue factor (TF) may play an essential role in embryonic vascular development and tumor angiogenesis. To further examine this relationship, the morphology of fully developed TF-deficient embryos and the growth of TF-deficient teratomas and teratocarcinomas were analyzed. In a 129/Sv genetic background, TF null embryos do not survive beyond mid-gestation. In contrast, 14% of 129/Sv x C57BL/6 TF-deficient embryos escape this early mortality and survive to birth. On gross and microscopic inspection, these late gestation, TF-deficient embryos appear normal. The growth and vascularity of TF(+/+), TF(+/-), and TF(-/-) teratomas and teratocarcinomas are indistinguishable. Thus, tumor-derived TF is not required for tumor growth and angiogenesis and the combined data do not support an essential role for TF in embryonic vascular development.

Determination of some metals in biological samples for monitoring purposes.

The biological monitoring of toxic and essential metals in biological material is important for the study of influence of environmental conditions on the human body. In this work, the determination of Cd, Pb and Hg in blood, urine and hair of children has been performed by atomic absorption spectroscopy. The electrothermal atomisation with Zeeman background correction was used for Pb and Cd determination and mercury was determined using Trace Mercury Analyser TMA 254. Methylmercury in hair was determined simultaneously. To check the method, SRM Lyphochek Urine Metal control--Biorad, Seronorm Trace Elements--Nycomed and GWB Human Hair (China) were used. The group of more than 100 children were chosen for the study. Statistical tests were used for the evaluation of the obtained results. The concentrations of all elements in all types of samples correspond to the "normal contents" published for the non-exposed population.

Targeted disruption of the murine tissue factor gene results in embryonic lethality.

Tissue factor (TF) is an integral membrane glycoprotein that is believed to be the physiologic initiator of the blood coagulation cascade. Disruption of the mouse tissue factor gene leads to embryonic lethality between days E9.5-E11.5 of gestation. On E9.5, TF(-/-) embryos appear indistinguishable from their TF(+/+) and TF(+/-) littermates. By E10.5, TF(-/-) embryos are severely growth retarded, appear nearly bloodless, and are in most cases dead. Initial observations suggest that TF(-/-) embryos are dying of circulatory failure. Approximately 15% of the TF(-/-) embryos survive beyond E10.5, but none complete gestation. Heterozygotes appear normal and free of bleeding complications.

Effect of photoperiod on body weight and reproductive performance of ringneck pheasants.

This study was conducted to determine the effects of exposing ringneck pheasants to different photoperiods on their body weights and reproductive performance. Ringneck pheasants were obtained from commercial sources for the first experiment and from the Pennsylvania Game Commission for the second. Birds were exposed to different periods of nonstimulatory light (8 hr of constant light and 16 hr of darkness daily) before they received 16 hr of light and 8 hr of darkness daily (stimulatory light). Data on body weight, feed consumption, semen volume, fertility, and egg production were obtained. The results indicated that ringneck pheasants grow faster when exposed to a period of nonstimulatory light. It was concluded that, if pheasant hens are to be raised under confinement and receive stimulatory light at 27 weeks of age, they should be exposed prior to that time to at least 6 weeks of nonstimulatory light.

The cumulation of chromium and arsenic species in fish (Poecilia reticulata).

Chromium-51 and arsenic-74 were used for the investigation of the uptake and the release of different chromium and arsenic species in fish. It has been found that only trimethylarsine can be rapidly taken up directly from water. The release of chromium(III), consumed by fish in food, is very rapid: about 99.9% of chromium is released within a few days. The same results were obtained with chromium(III) acetylacetonate or chromium(III) ethylenediaminotetraacetate. About 95% of arsenic acid, methylarsonic acid, dimethylarsinic acid or arsenic(III) diethyldithiocarbamate are released within a few days whereas the remaining arsenic is released with the biological half time 35 +/- 5 days.

The cumulation of zinc and cadmium in fish (Poecilia reticulata).

Zinc-65 and cadmium-115 m were used for the investigation of the uptake and the release of zinc and cadmium in fish. It has been found that the uptake of these elements directly from water is relatively low. Zinc and cadmium, consumed by fish in food, are released with the biological half-time 0.25 +/- 0.05 days (94%) and 65 +/- 9 days (6%) for zinc, 0.25 +/- 0.05 days (98.5%) and 36 +/- 6 days (1.5%) for cadmium. The comparison with data obtained for mercury species shows that the cumulation of these elements in fish increases in the order cadmium, zinc, inorganic mercury (II), phenylmercury and methylmercury.

The cumulation of methylmercury in fish (Poecilia reticulata).

Methylmercury labelled with mercury-203 was used for the investigation of the uptake and the release of methylmercury in fish. It has been found that methylmercury compounds adsorbed on fish food remain completely in fish and that they are released with the biological half-time of 110 +/- 20 days. The cumulation of methylmercury from water is very rapid: the cumulation constant is 237 +/- 67 days-1. Equations for the calculation of the concentration of methylmercury in fish were derived and compared with the uptake of phenylmercury and inorganic mercury.