Tritium intake by exposure to plastic case watches.

In recent years tritium has been used in plastic case watches as permanent light sources on watch dials. To measure the release of tritium through the plastic cases, 82 different waterproofed watches were immersed in a water bath for 24 h, and the tritium concentration of the water was measured. The mean tritium release rate was 24,400 Bq d(-1) ranging from 110-162,000 Bq d(-1). Parallel measurements were made to determine the tritium concentration in the urine of 108 wearers of plastic case watches. The mean tritium concentration in urine was 197 Bq L(-1) up to 1,133 Bq L(-1). The whole body dose resulting from exposure to plastic case is negligibly small but given the pathway of skin absorption, the annual skin dose is 3-4 times higher than the dose limit for the public. Plastic case watches are collector's items and are often kept with other watches in glass cabinets or other containers. Storage of a large number of such watches in one container causes tritium to diffuse through the plastic cases and to contaminate watches that did not contain tritium at first. If the container is more or less airtight, the tritium concentration in the container and the tritium release rate from the watches can reach levels up to 4 MBq d(-1).

Induction of cytokine synthesis and fever suppresses REM sleep and improves mood in patients with major depression.

Beneficial effects of inflammatory events on certain psychiatric disorders, including depression, were reported sporadically by ancient Greek physicians, but have been described also in our times by a few psychiatrists during the past decades. During febrile inflammatory events, mediators of the immune system such as interleukin-1 can be detected in the brain and may act on their respective receptors which have also been demonstrated in the brain. Since cytokines such as interleukin-1 have been shown in animal studies to exert sedative behavioral effects, to be somnogenic, and to induce slow-wave sleep (SWS), we performed a pilot study to evaluate scientifically the anecdotically reported beneficial effects of inflammatory states on depressive disorders. Mood and sleep parameters were monitored in seven drug-free, severely depressed patients before, during, and after the administration of a single dose of endotoxin. All patients responded with a short pulse of increased synthesis of the cytokines tumor necrosis factor, interleukin-1, and interleukin-6 and elevated body temperature for several hours. During the night following endotoxin administration, rapid eye movement (REM) sleep was significantly suppressed, while changes in slow wave sleep were not significant. During the next day, all patients were in a significantly improved mood; however a rebound of REM sleep was observed in the second night after endotoxin administration and mood worsened again during the next days, indicating an only transient beneficial effect of the treatment.

Mitigation of indoor radon in an area with unusually high radon concentrations.

In an area of unusually high indoor radon concentrations of up to 270,000 Bq m-3, four houses were selected for mitigation of indoor radon. Methods used were basement sealing, soil depressurization, a mechanical intake and outlet ventilation system with heat exchanger in the basement, and a multilayer floor construction using a fan to suck radon from a layer between bottom slab and floor. Basement sealing proved unsuccessful, the radon concentration remained unchanged after the mitigation attempt. The most successful remedial measure was soil depressurization using two fans and loops of drainage tubes to withdraw radon from the region under the floor and outside the walls of the basement and from soil under the part of the house without a basement. This method reduced the basement radon level in winter by about a factor of 200, i.e., from 100,000 Bq m-3 to 500 Bq m-3, and the ground-floor level by about a factor of 400. As regards the mechanical intake and outlet ventilation system with heat exchanger in the basement, it is essential to ensure that ventilation provides increased air pressure in the basement compared to outdoors. Unbalanced mechanical intake and outlet ventilation may decrease the air pressure indoors compared to outdoors, leading to increased radon concentrations. Optimization of this method reduced radon concentrations from 200,000 Bq m-3 to 2,000-3,000 Bq m-3 in winter. In one house with only a very small basement, a multilayer floor construction using a fan to suck radon from a layer between the bottom slab and floor was found to reduce radon concentrations on the ground floor from 25,000 Bq m-3 to about 1,700 Bq m-3 in winter. The results show that even in areas with extremely high radon concentrations, effective mitigation of indoor radon can be accomplished if suitable techniques are used. The evaluation of the different mitigation methods shows good coincidence with the ICRP 65 report.

Keratitis solaris and sunbeds.

Keratitis solaris is caused by ultraviolet radiation in the range 200-320 nm. The threshold dose for keratitis solaris is 40 J/m2 for short-term exposure. We measured the emission spectra of 22 sunbeds in the range 250-500 nm with a high-resolution double monochromator and calculated the exposure times for the threshold dose of keratitis solaris. Depending on the type of lamp used, the exposure times ranged from 90 s to 3.5 h. Lamps with short exposure times for keratitis solaris can induce keratitis solaris if protective goggles are not used (e.g., to achieve a uniform tan of the eye area) and if the eyes are opened briefly several times, perhaps, to look at a watch. Generally, sunbed users have no way of ascertaining the lamp type or its emission spectrum and of determining the exposure time for the threshold dose of keratitis solaris.

High indoor radon concentrations in an Alpine region of western Tyrol.

In a village in western Tyrol, Austria (Umhausen, 2,600 inhabitants), unusually high indoor radon concentrations were measured, and the lung cancer mortality rate was found to be higher than that of the total population of Tyrol (620,000 inhabitants). Annual means of radon concentrations were found to be particularly high in the area between the two rivers Otztaler Ache and Hairlachbach, geologically an alluvial fan of a giant rock slide of granitic gneisses (area A, median of annual means on the ground floors: 1,868 Bq m-3); radon concentrations were comparatively low in the rest of the village (area B, median of annual means on the ground floors: 182 Bq m-3). On the basis of these medians, the annual exposures were calculated according to the ICRP model (area A: 58.8 x 10(5) Bq h m-3; area B: 5.7 x 10(5) Bq h m-3). Data taken from the Cancer Registry of Tyrol were used to determine the age- and sex-standardized lung cancer mortality rate (area A: 6.17; area B: 1.43).

Unusually high indoor radon concentrations from a giant rock slide.

In a village in western Tyrol, Austria (Umhausen, approximately 2600 inhabitants) unusually high indoor radon concentrations were measured. The medians were found to be 3750 Bq/m3 (basements) and 1160 Bq/m3 (ground floors) in winter, and 361 Bq/m3 (basements) and 210 Bq/m3 (ground floors) in summer. Maximum radon concentrations of up to 274,000 Bq/m3 were registered. The unusually high radon concentrations are due to the geology of the locality. The part of Umhausen with the highest radon concentrations is built on an alluvial fan of a giant rock slide (granitic gneiss). Measurements of the radon exhalation rate from soil showed a median of 0.4 Bq/m2/s, measurements of the radium content of rock samples yielded a median of 125 Bq/kg. The material of the rock slide is heavily fractured so that an elevated emanating power and an increased diffusion coefficient for radon in soil must be assumed. Given a diffusion coefficient of 8 x 10(-6) m2/s and an emanating power of 0.3, the median exhalation rate of 0.4 Bq/m2/s is obtained at a radium concentration of 125 Bq/kg. The rock slide is therefore considered to be the main source of radon. The abnormally high radon concentrations in Umhausen coincide with a statistically significant increase in lung cancer mortality (age and sex standardized mortality rate = 3.9, 95% C.I.: 2.9-5.1); the control population is the population of the entire Tyrol (630,000 inhabitants).

[Sound frequency analysis for identification of venous air embolism]. / Frequenzanalyse von Geräuschen zur Erkennung von venösen Luftembolien.

Air emboli occurring during surgery are considered to be life-threatening incidents. With the aim of achieving acoustic identification of venous air emboli, a frequency analysis of the sounds induced by an air embolism (millwheel murmurs) as well as of all other unusual sounds, was undertaken during 20 operations, and in experiments with animals. The frequency spectra of the sounds induced by air emboli are characterised by an increase in the amplitudes in the frequency range 1,100 to 3,000 Hz, while the amplitudes of normal heart sounds continuously decrease with increasing frequency. The frequency spectrum was examined for characteristics using an electronic filter system. The sounds induced by air emboli can be clearly distinguished from normal heart sounds. During operations on patients, suction sounds occur, the frequency patterns of which are not easy to distinguish from those of embolus-induced sounds, although an acoustic distinction can be made via a stethoscope or a loudspeaker. With optimal adjustment of the filter system, 73 out of 81 (90%) embolism-related sounds were correctly identified in animal experiments. On no occasion were normal heart sounds wrongly identified as due to an embolus. However, an embolus sound was frequently mimicked by interfering sounds such as those produced by artificial respiration, and other ambiend sounds. By modifying the oesophageal catheter to achieve optimal suppression of interfering sounds, this filter system could be developed into an alarm.

Spectral transmission of the optical media of the human eye with respect to keratitis and cataract formation.

The spectral transmissions of cornea, aqueous humour, lens and vitreous humour of human eyes were measured in the range from 250 nm to 800 nm in 1 nm steps using a high resolution double monochromator. Cornea and lens are good cut off filters; 1% transmission was measured in various cornea samples between 291 and 298 nm, and in different lenses between 389 and 414 nm. Aqueous humour and vitreous humour showed high transparency (80%) at lambda > 320 nm. The wavelength range of keratitis effective irradiance was found to be completely within the wavelength range of absorption of the cornea, that of cataract effective irradiance was found to be at the short wavelength end partly outside the wavelength range of absorption of the lens. It may therefore be supposed that the action spectrum of cataract obtained by animal experiments is applicable to the human eye only with certain reservations.

Biological effectiveness of solar UV radiation in humans.

Solar UVB radiation is prejudicial to the health of humans in a number of ways. Erythema and photodermatoses are acute reactions of the skin; keratitis and conjunctivitis are acute reactions of the eye. Various types of skin cancer, accelerated aging of the skin, and cataract formation in the crystalline lens are reactions that appear with great latency. UV radiation can also cause damage to the immune system and DNA. For the period 1981-1991, an increase in erythemal effective UVB radiation of +(7 +/- 4)% per decade was measured in a non-polluted high mountain area (Jungfraujoch, 3576 m a.s.l., Switzerland). This increase is related to a decrease in stratospheric ozone. The effects on human health are discussed. A 10% ozone reduction increases non-melanoma skin cancer by 26% and cataract by 6 to 8%.

Increased radon concentrations in classrooms used for pottery workshops.

In a pilot study of nine schools the radon (Rn) concentrations were measured systematically. The mean radon concentrations in the classrooms on the ground-floor and on higher floors was 52 Bq/m3, which is equivalent to the mean values in Central Europe. Several of the basement rooms used for handicraft lessons had significantly increased Rn levels with a mean concentration of 617 Bq/m3. In all other parts of the basement Rn levels were clearly lower with a mean concentration of 136 Bq/m3. In the rooms used for handicraft lessons numerous articles of pottery were on display. After removing these the Rn in air concentration was reduced to a mean value of 83 Bq/m3.