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.

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.

Use of physiological and genetic algal tests for the hygienic evaluation of pollutants in waters. Part I. 226Ra studies.

After exposure for several days of intensively growing algal cultures to a radium concentration of 10(-6) g.1(-1) the physiological and genetic responses of Chlorella kessleri and Scenedesmus obliquus cells could be clearly demonstrated. Of physiological characteristics, we recorded the frequency of cells with a reduced number of autospores, the length of the lag phase and cell survival. Of genetic responses, the frequencies of delayed lethal and sublethal effects, the frequencies of minute colonies, colonies with big cells and scabby colonies, and the frequencies of pigmentation changes were followed. The above concentration produced no toxic effect. No simple and clear-cut correlation was found between the recorded responses and the amount of accumulated radium in algal cells. For an interpretation of the mutagenic effect we had to assume a homogeneous radioactive irradiation of the mixed cell suspension. We had also to take into account the participation of repair systems of algae with regard to their survival or manifestation of mutagenic changes in individuals in which mutagenesis had been induced.

Hygienic importance of increased barium content in some fresh waters.

In surface waters of the mining and processing areas of uranium ore there is an increased content of free and bound barium ions due to the use of barium salts for the treatment of waste and mine waters containing radium. In model experiments with the algae Ankistrodesmus falcatus, Chlorella kessleri and Scenedesmus obliquus, we studied the effect of Ba2+ on the accumulation of 226Ra. It was found that the accumulation of radium by algae is negatively influenced with barium concentrations higher than 1 mg.l-1. The accumulation of barium of organisms of primary production was studied using 133BaCl2. At a barium content in the medium of 4.0, 0.46 and 0.04 mu. l-1, the algae accumulated 30-60% of the added amount of barium during an exposure of 15 days. Biochemical analyses showed that barium is bound to the cellular membrane and to other components of the algal cell that cannot be extracted with water or alcohol.

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.