Sensitivity of zebrafish (Danio rerio) embryos to hospital effluent compared to Daphnia magna and Aliivibrio fischeri.

The Fish Embryo Acute Toxicity (FET) Test was adopted by the Organisation for Economic Co-operation and Development as OECD TG 236 in 2013. The test has been designed to determine acute toxicity of chemicals on embryonic stages of fish and proposed as an alternative method to the Fish Acute Toxicity Test performed according to OECD TG 203. In recent years fish embryos were used not only in the assessment of toxicity of chemicals but also for environmental and wastewater samples. In our study we investigated the acute toxicity of treated wastewater from seven hospitals in the Czech Republic. Our main purpose was to compare the suitability and sensitivity of zebrafish embryos with the sensitivity of two other aquatic organisms commonly used for wastewater testing - Daphnia magna and Aliivibrio fischeri. For the aim of this study, in addition to the lethal endpoints of the FET test, sublethal effects such as delayed heartbeat, lack of blood circulation, pericardial and yolk sac edema, spinal curvature and pigmentation failures were evaluated. The comparison of three species demonstrated that the sensitivity of zebrafish embryos is comparable or in some cases higher than the sensitivity of D. magna and A. fischeri. The inclusion of sublethal endpoints caused statistically significant increase of the FET test efficiency in the range of 1-12 %. Based on our results, the FET test, especially with the addition of sublethal effects evaluation, can be considered as a sufficiently sensitive and useful additional tool for ecotoxicity testing of the acute toxicity potential of hospital effluents.

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.

Health risk of urban soils contaminated by heavy metals.

The paper presents the results of geochemical investigations carried out in the city of Prague. Czech Republic, between the years 1994-1997, by the Czech Geological Institute, National Institute of Public Health and Hygiene Stations of Prague. Exposure assessment for children as the most sensitive population, based on soil ingestion pathway, indicates that lead is the major pollutant of concern, especially in the central regions of the city. Direct exposure assessment was done by analyzing blood and urine samples collected from children aged 3-6 years. Blood lead levels were the only biomarker significantly higher as compared to the control group (32.1 +/- 17.4 microg/l, 25.1 +/- 15.4 microg/l). This pilot study supports the establishment of a new sub-system within the already existing System of Monitoring the Environmental Impact on Population Health of the Czech Republic.

[Reference values, metabolism and findings of abnormal values of magnesium in childhood]. / Referencní hodnoty, metabolismus a nálezy abnormálních hodnot horcíku v détském veku.

In the introduction we summarize specifics of reference values and metabolism of magnesium in childhood. We studied the frequency of abnormal values of magnesium in both children and adults hospitalized in Faculty Hospital Motol, Prague. We analyzed 6761 tests of S-Mg and 356 dU-Mg results located in archives of Department of clinical biochemistry (1. 1. 1992-1. 11. 1995). The frequency of low level of S-Mg (< 0.65 mmol/l) was 14%. Hypermagnesemia was present in 1.6% of the total number of cases. We found low values of dU-Mg in 20% of the total number of cases, hypermagnesiuria was present in 8.4% cases. We also proved that hypomagnesemia is more frequent in both boys and men than in girls and women. Critical values of S-Mg below 0.5 mmol/l are less frequent (84 cases). Estimated frequency of clinical significant hypomagnesemia in hospitalized patients was about 1.25%.

Effect of mercury on selenium binding to rat lens proteins in vitro.

The effect of mercury in the incubation medium on selenium influx, efflux and distribution was studied in eye lenses of 14-day-old rats. The presence of mercury did not affect the uptake of selenium into a water-soluble protein fraction but increased considerably its content in water-insoluble proteins and thus also the selenium influx into experimental lenses. The efflux from experimental lenses yielded significantly lower amounts of released selenium, most of the selenium being bound to proteins. In contrast, efflux experiments with control lenses showed most of the selenium to be in the medium in the form of free anions. The selenium content in experimental lenses decreased after the efflux only in the fraction of water-soluble proteins, while the decrease in control lenses was found in both fractions and was relatively higher in water-insoluble proteins. During both influx and efflux experiments the lenses of both groups released a small of proteins, but no difference found between the two groups.