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Biomedical subjects

U Ewers

Publications and source records attributed to U Ewers.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Exposure to mercury in the population. I. Mercury concentrations in the urine of normal subjects].

The levels of mercury were determined in 24 h urine samples collected from 703 subjects (age 1-79 years) living in the Eastern part of the Ruhr area (West-Germany). The mean HgU level was 0.75 micrograms/l (range less than 0.1-19.3 micrograms/l) and the mean HgU level standardized for creatinine was 0.64 micrograms/g creatinine (range: less than 0.1-27.4 micrograms/g creatinine). The mean mercury excretion per 24 h was 0.48 micrograms in subjects less than 18 years and 0.99 micrograms in subjects greater than 18 years. Females were found to have, on average, higher HgU levels and also a higher excretion of mercury per 24 h than males. Subjects greater than 18 years had significantly higher HgU levels than subjects less than 18 years of age. The effect of age was found to be substantially more pronounced in females than in males. Smoking did not affect the urinary mercury excretion.

Adolescent↗
PubMed1990

[Exposure to mercury in the population. II. Mercury release from amalgam fillings].

Urinary levels of mercury (HgU) were measured in 93 males and females aged 18-63 years. Subjects with amalgam fillings (n = 72) had, on average, significantly higher levels of mercury in urine (mean = 0.57 microgram Hg/l and 0.79 microgram Hg/g creatinine, respectively) than subjects without amalgam fillings (n = 21; mean = 0.18 micrograms Hg/l and 0.24 microgram Hg/g creatinine, respectively). Urinary mercury excretion was significantly correlated with the number of amalgam surfaces (log HgU (microgram/l) vs. number of amalgam fillings: r = 0.435, P less than 0.001; log HgU (microgram/g creatinine) vs. number of amalgam fillings: r = 0.575, p less than 0.001). The results indicate that internal mercury exposure from amalgam fillings is, on average, higher than internal exposure to mercury from food and other sources.

Adult↗
PubMed1990

[Lead and cadmium burden of children in Stolberg].

In 1989, blood lead and blood cadmium levels were determined in 229 children (age 6-7 years) living at Stolberg (West Germany). The area of Stolberg is heavily polluted by lead and other toxic metals due to emissions from a large primary lead smelter. The mean blood lead level was 6.3 micrograms/dl (range 2.6-15.5 micrograms/dl) and the mean blood cadmium level was 0.14 microgram/l (range less than 0.1-0.5 microgram/l). The blood lead levels were affected by the following factors: living in the central urban area with high lead levels in dust fall-out; living in a family of foreigners; involuntary inhalation of smoke at home; living in a family with a family member employed in the lead industry. Children from foreign families also had higher blood cadmium levels than children from German families. However, inhalation of tobacco smoke did not affect the blood cadmium levels. In total, there has been a significant decline of blood lead and blood cadmium levels among children from the Stolberg area since 1982.

Air Pollutants, Occupational↗
PubMed1990

[Lead and cadmium content in deciduous incisors of children from Duisburg and Gummersbach--developing trend 1976-1988].

Shed deciduous teeth (incisors only) were collected from children (n = 199) living in Duisburg and Gummersbach (F.R.G.) in 1976 and 1988. The teeth were analysed for lead and cadmium. Considering all teeth, there was a significant of tooth lead and tooth cadmium from 1976 to 1988. The reduction was between -40 and -50% for tooth lead and -45% for tooth cadmium. Regarding tooth lead, the reduction was more pronounced in children from Duisburg, an area heavily polluted by lead and other heavy metals due to the presence of large iron and steel plants and a large lead-/zinc smelter. Teeth from the upper jaw were found to have higher lead and calcium concentrations than teeth from the lower jaw. Moreover, it was found that central incisors had higher lead and cadmium concentrations than lateral incisors. Even after the effects of jaw and tooth type had been allowed for, the reduction of tooth lead and tooth cadmium could be demonstrated. Children living in pre-war houses were found to have higher tooth lead and tooth cadmium levels than children living in post-war houses. The higher lead and cadmium burden of children living in old houses seems to be related to a higher degree of exposure to lead and cadmium via drinking water resulting from the release of these metals from old zinc-plated steel water pipes. In total, our results indicate that there has been a significant decrease of lead and cadmium exposure in West-German children since the mid-70s. The reduction of tooth lead levels parallels the decrease of blood and bone lead levels, which has been observed in previous studies.

Cadmium↗
PubMed1990

[Blood lead and blood cadmium concentrations in 55-66-year-old women fron different areas of Nordrhein-Westfalen--chronological trends during 1982-1988].

Blood lead levels were determined in 3098 55-66 year-old women living in different areas of Northrhine-Westphalia (F.R.G.). Blood cadmium levels were determined in a subgroup of 2538 women. The studies were performed between 1982 and 1988. The results show that there has been a further fall of blood lead levels in the general population of West-Germany since the CEC blood lead surveys of 1979 and 1981. A comparable reduction of blood cadmium was not noted. Residents of large urban agglomerations had, on average, slightly higher blood lead levels than residents of small cities located in rural areas (+0.2-0.5 microgram/dl). With regard to blood cadmium, no differences were seen. Smokers were found to have, on average, 3-4 times higher blood cadmium levels than non-smokers. Blood lead was also elevated in smokers when compared to non-smokers. The highest blood lead levels recorded were in the range of 15-30 micrograms/dl. The data further suggest that lead mobilization during conditions of bone demineralization, e.g. in cases of osteoporosis, does not result in toxic blood lead levels in postmenopausal women.

Aged↗
PubMed1989

Levels of benzene and other volatile aromatic compounds in the blood of non-smokers and smokers.

The concentrations of benzene, toluene, ethylbenzene, and o-, m-and p-xylene were measured in venous blood samples collected from 13 non-smokers and 14 cigarette smokers. The blood samples were analysed by a purge and trap technique followed by gas chromatography/mass spectrometry/computer analysis. The above-mentioned volatile organic compounds (VOC) could be detected in measurable amounts in all blood samples. This finding seems to reflect the ubiquitous exposure of humans to these agents in the urban environment, in non-smokers as well as in smokers. Smokers were found to have significantly higher blood concentrations of benzene (median 547 ng/l) and toluene (median 2201 ng/l) than non-smokers (median 190 ng/l and 1141 ng/l, respectively). The concentrations of ethylbenzene and xylenes also tended to be higher in smokers when compared to non-smokers. The different concentrations of these compounds in the blood of non-smokers appear to reflect the common concentration pattern found in outdoor urban air as well as in indoor air and also seem to be influenced by the different blood/air partition coefficients of these compounds. The results indicate that smoking is associated with a significant additional exposure to VOC, in particular to benzene and toluene.

Benzene Derivatives↗
PubMed1989

Exposure to lead and cadmium of children living near a lead smelter at Lavrion, Greece.

Exposure of children of the Greek town of Lavrion to lead and cadmium has been evaluated by determination of the levels of lead (PbB) and cadmium (CdB) in the blood of 514 children living in the town. The Lavrion area is heavily polluted by lead owing to the presence of a large lead-zinc mining and smelting industrial complex. The industrial PbB level (geometric mean) was 21.7 micrograms dl-1 (range 7.4-79.8 micrograms dl-1). The CdB levels were, on average, 0.36 micrograms l-1 (range 0.1-3.1 micrograms l-1). The results were evaluated with respect to a number of constitutional, social and environmental variables, such as age, gender, distance of the school from the lead-zinc mining and smelting complex, and occupation and education of the father.

Age Factors↗
PubMed1989

C3c concentrations in sera of persons living in areas with different levels of air pollution in Northrhine-Westphalia (Federal Republic of Germany).

A number of air pollutants is known to affect the immune system resulting in alterations of the complement activity in serum. We determined the levels of C3c, one of the activation products of the component C3, in serum samples obtained from various population groups living in areas with different levels of air pollution in Northrhine-Westphalia (FRG). The results show that the serum C3c levels tend to be increased in subjects living in areas with elevated levels of air pollution. By applying a linear regression model it can be demonstrated that a significant part of the variance of the C3c concentrations is explained by the residence area factor after making allowance for the effect of various confounders. The increase of the serum C3c concentrations appears to result from an increased activation of the complement component C3. The underlying mechanisms as well as the pathophysiological significance of these findings are unknown.

Age Factors↗
PubMed1989

[Exposure of children to benzene and other motor vehicle emissions].

The concentrations of benzene, toluene, and lead and the percentage of carboxyhemoglobin (COHb) were measured in the venous blood of 48 children living in a central urban area with high traffic density (Cologne, FRG). The same parameters were also evaluated in a reference group of children (n = 72) living in a small city located in a rural area of West-Germany (Borken, Münsterland). The above named parameters could be quantitated in all blood samples. The children living in the central urban area had, on average, significantly higher concentrations of benzene, toluene, lead, and COHb in blood than the children of the reference group. The blood benzene concentrations were, on average, 71% and the toluene concentrations 56% higher in the urban children when compared to the reference group. The median values of the urban group/reference group were: benzene, 115/70 ng/l; toluene, 545/370 ng/l; lead, 5.2/4.7 micrograms/dl; COHb, 0.9/0.6%. It is concluded that the higher levels of benzene, toluene, lead, and COHb found in the blood of the urban children result from the higher atmospheric concentrations of these pollutants generally found in central urban areas with high traffic density.

Air Pollution↗
PubMed1988

Environmental exposure to thallium.

This paper reviews recent data and findings concerning the sources of thallium in the environment and its current environmental levels and exposures, particularly with respect to human exposure. Special emphasis is given to some recent cases of environmental thallium pollution that were recognized around several cement factories in the Federal Republic of Germany. Contaminated food grown in these areas gave rise to a significantly increased thallium exposure of the population living there. Recent studies show that the thallium level in human urine normally is below 1 micrograms/g creatinine and that the normal concentration range of thallium in human air is approximately 5-10 ng/g. These data allow to recognize even minor undue exposure to thallium in the work and general environment.

Environmental Exposure↗
PubMed1988

Exposure to lead and cadmium of children living in different areas of north-west Germany: results of biological monitoring studies 1982-1986.

Between 1982 and 1986 several surveys were carried out to determine the levels of lead and cadmium in blood, urine, and shed deciduous teeth (incisors only) of children living in rural, suburban, urban, and industrial areas of North-West Germany. Blood lead (PbB) and blood cadmium (CdB) were measured in about 4000 children. In rural, suburban and urban areas the median PbB levels vary between 5.5 and 7 micrograms/dl, with 98th percentiles varying between 10 and 13 micrograms/dl. The median CdB levels are between 0.1 and 0.2 microgram/dl, with 95th percentiles between 0.3 and 0.4 microgram/l. Children from urban areas have significantly higher PbB levels than children from rural and suburban areas. Regarding CdB no differences could be detected. Children living in areas around lead and zinc smelters, particularly those living very close to the smelters, have substantially increased PbB and CdB levels. Children from lead worker families also have substantially increased PbB and CdB levels. The lead levels in shed milk teeth (PbT) were determined in about 3000 children. In rural, suburban and urban areas the median PbT levels are between 2 and 3 micrograms/g, with 95th percentiles between 4 and 7 micrograms/g. Children from urban areas have significantly higher PbT levels than children from rural and suburban areas. The highest PbT levels (on a group basis) are in children from nonferrous smelter areas. The median levels of lead in urine (PbU) are between 6 and 10 micrograms/g creatinine, with 95th percentiles between 20 and 30 micrograms/g creatinine. Children from polluted areas have higher PbU levels than children from less polluted areas. The median levels of cadmium in urine (CdU) are in the order of 0.1 microgram/g creatinine, with 95th percentiles being in the range of 0.5 and 1.0 microgram/g creatinine. Girls have higher CdU levels than boys. There are no differences between groups of children from different areas. Children from lead worker families have higher PbU and CdU levels than otherwise comparable children. The results of the present studies indicate a further decrease of PbB in children from North-West Germany since the CEC blood lead campaigns carried out in 1979 and 1981. The decrease of lead exposure also seems to be reflected by a decrease of tooth lead levels.

Adolescent↗
PubMed1987

Cadmium in kidney cortex of inhabitants of North-West Germany: its relationship to age, sex, smoking and environmental pollution by cadmium.

The cadmium concentration in kidney cortex (CdKc) was determined in 388 deceased persons, who at the time of death had lived in the cities of Düsseldorf and Duisburg, Federal Republic of Germany (FRG), and surrounding areas. The average CdKc concentration was found to be 17.1 micrograms/g wet weight. Individual values range from less than 0.4 to 94.3 micrograms/g wet weight. The CdKc levels rapidly increase during the first decades of life. At the age of about 40 years, a plateau phase is reached. At high ages (greater than 70 years), the CdKc levels tend to decrease. Cigarette smokers have significantly higher CdKc concentrations than non-smokers. The increase of CdKc depends on the number of cigarettes smoked. Cigar and pipe smokers have slightly increased CdKc levels compared to non-smokers. Non-smokers who had spent the major part of their life in the area of Duisburg, a cadmium-polluted area, have, on the average, significantly higher CdKc levels than non-smokers from the less-polluted surrounding areas. In smokers the residential factor is masked by the effect of cigarette smoking.

Adult↗
PubMed1986

Human exposure to volatile halogenated hydrocarbons from the general environment.

The objective of this study was to assess individual human exposure to volatile halogenated hydrocarbons (VHH) under normal environmental conditions by means of biological monitoring, i.e. by the measurement of these compounds or their metabolites in body fluids, such as blood, serum, and urine. Blood samples of 39 normal subjects without known occupational exposure to these agents were examined for the occurrence of VHH. The following compounds were present in quantifiable concentrations in 60 to 95% of the blood samples examined: chloroform (median 0.2 microgram/l; range less than 0.1-1.7 microgram/l), 1,1,1-trichloroethane (median 0.2 microgram/l; range less than 0.1-3.4 micrograms/l), tetrachloroethylene (median 0.4 microgram/l; range less than 0.1-3.7 micrograms/l). Trichloroethylene could be detected in 31% of all blood samples (median less than 0.1 microgram/l; range less than 0.1-1.3 microgram/l). In addition, the levels of trichloroacetic acid (TCA) were determined in serum and 24-h urine samples of 43 and 94, respectively, normal subjects. TCA was present in measurable concentrations in all serum and urine samples examined. The median of the TCA levels in serum was 21.4 micrograms/l (range 4.8-221.2 micrograms/l) and in urine 6.0 micrograms/24 h (range 0.6-261.4 micrograms/24 h). The results are discussed in relation to data from the literature on human exposure to VHH from the general environment, i.e. via air, food, and water. The upper normal limits calculated from the results of this investigation can be used to detect even minor excessive exposures to VHH.

Adult↗