Exposure of dentists and assistants to mercury: mercury levels in urine and hair related to conditions of practice

A study of 162 dentists' and their assistants' mercury levels in hair and urine, and of questionnaire items regarding mercury consumption, revealed some striking relations. The mercury concentrations in both hair (Hg-H) and urine (Hg-U) were somewhat higher in the dentists than the assistants. There was no relation between concentrations in hair and urine. The method of condensation of amalgam was positively related to Hg-U; the vibration method was negatively related. Hg-U was also positively related to number of fillings and hours in own practice. The relation of Hg-U to ventilation in the surgery applied only to the dentists.

Simultaneous quantification of five odorous steroids (16-androstenes) in the axillary hair of men

Five 16-androstenes have been simultaneously quantified in extracts of the axillary hair of men (age range 18-40 years) using combined capillary gas chromatography-mass spectrometry, with specific ion monitoring. Quantities found (pmol/mg.hair, with approximate 24-h totals in parentheses) were: 5 alpha-androst-16-en-3-one, 0-15 (0-433); 4, 16-androstadien-3-one, 0-143 (0-4103); 5,16-androstadien-3 beta-ol, 0-3.5 (0-728); 5 alpha-androst-16-en-3 alpha-ol, 0-17 (0-1752) and 5 alpha-androst-16-en-3 beta-ol, 0-4 (0-416). There were no significant relationships with age of the subjects for any of the steroids measured but significant relationships were found between the amounts of the two ketones and between 5 alpha-androst-16-en-3 alpha- and 3 beta-ols. These findings may indicate the existence of a pathway of metabolism in axillary bacteria in which 4,16-androstadien-3-one is reduced to 5 alpha-androst-16-en-3-one and thence to the 3 alpha- and 3 beta-alcohols. The data are discussed in the context of axillary odour because of the low olfactory thresholds of several of the 16-androstenes measured and because of the relatively large quantities found in some subjects.

Atomic absorption spectrophotometric microdetermination of total mercury in undigested biological samples

The influence of reaction time upon stannous (II) chloride as a reductant in the cold-vapor atomic absorption spectrophotometric method was investigated. In this comparative study, virtually all operating conditions, including volumes and chemicals used, were made identical except for the redesigning of the reaction vessels. The use of a reaction mixing time of 2 minutes (TR method), rather than immediate bubbling with aspiration (IL method) of total mercury from undigested biological samples, has several advantages. There is an average 4.5-fold increase in sensitivity of peak height readings with virtually no loss of mercury vapor from the reaction vessel by diffusion. Using the TR method also eliminated interaction of mercury with the matrices investigated, viz., undigested blood, undigested saliva, undigested urine, and digested hair samples. The average recovery for the TR method was superior to the IL method, 99.3 +/- 3.2% vs. 84.7 +/- 3.3%, p less than 0.05. In addition, mercury concentrations determined with the TR method were identical using either peak area or peak height readings. It was also found that concentrations determined using either the formulae given by Magos and Clarkson (4) and Farant et al. (5) or an aqueous calibration curve were equivalent. Only 0.2-1.0 mL of biological samples was needed for each analysis in the study.

Pigment types in sheep, goats, and llamas

Pigment types in various colors of fiber from sheep, goats, and llamas were assayed by a method using high performance liquid chromatography. In these three species the black/gray group is due to eumelanin, which is fully intense in all three species. Red phenotypes are due to pheomelanin and fade considerably with age in fiber from sheep and goats, but not in llamas. This phenomenon has implications on the genetic mechanisms used in generating white fiber. Brown phenotypes in sheep are due to eumelanin, in goats these phenotypes are equivocal, and they were not observed in llamas.

An improved method for the histological preparation of single hairs and dust samples--morphological and immunological examination

An improved method of the serological and morphological investigation of human hair is reported. The hair was firmly fixed onto a microscopic slide with cellophane tape and observed microscopically to confirm the cuticula images and the presence of the medulla. A piece of the hair containing the medulla was dissected, embedded in paraffin, and a cross section of this hair was prepared. By treating the sample with immunohistochemistry (biotin-antibiotin ABC technique), the blood type of the hair was confirmed definitively. Dust containing shaved beard can be examined in the same way.

Isolation and characterization of high-molecular mass DNA from hair shafts

Experiments to identify species by DNA analysis of their hair failed so far because no DNA could be isolated from hair shafts. In this work the preparation of DNA from human--as well as from animal hair shafts (alpaca, angora-rabbit, cashmere, cashgora, mohair, merino and yak) is described for the first time. In general the isolated DNA shows a length of more than 20 kbp. The species of the hair shaft samples could be exactly identified by DNA hybridization experiments. The isolated DNA from hair shafts allow new possibilities to identify species and individuals employing techniques from molecular biology.

Trichothiodystrophy without photosensitivity. Biochemical, ultrastructural and DNA repair studies

A case of trichothiodystrophy (TTD) without photosensitivity is reported in an 8-year-old girl. Electron microscopic (EM) examination of the keratinocytes showed fibrillary bundles in the cytoplasm thinner and less electron dense than those of the normal cells and large membrane-bound vacuoles filled with granular-filamentous material. These findings could indicate a disturbance in the protein metabolism in tissues of ectodermal origin, explaining also the functional abnormalities of the central nervous system in TTD patients. The results of cellular DNA repair studies after UV irradiation in cultured fibroblasts showed normal levels of unscheduled DNA synthesis. This finding indicates that UV hypersensitivity is not constantly present in TTD.

Pigment types of various color genotypes of horses

Hair samples of various colors of horses were analyzed for content of both eumelanin and pheomelanin by a procedure using high performance liquid chromatography. The results are in accord with generally accepted genetic hypotheses accounting for the various colors. However, the results support the hypothesis that the chestnut/sorrel group of colors is conditioned by the extension locus, not the brown locus. The results also indicate that the brown locus is a likely contributor to some rare color phenotypes.

DNA typing from single hairs

The characterization of genetic variation at the DNA level has generated significant advances in gene and disease mapping, and in the forensic identification of individuals. The most common method of DNA analysis, that of restriction fragment length polymorphism (RFLP), requires microgram amounts of relatively undegraded DNA for multi-locus typing, and hundreds of nanograms for single-locus comparisons. Such DNA frequently cannot be obtained from forensic samples such as single hairs and blood stains, or from anthropological, genetic or zoological samples collected in the field. To detect polymorphic DNA sequences from single human hairs, we have used the polymerase chain reaction (PCR), in which specific short regions of a gene can be greatly amplified in vitro from as little as a single molecule of DNA. We have detected genetically variable mitochondrial and nuclear DNA sequences from the root region of shed, as well as freshly-plucked, single hairs; mitochondrial DNA (mtDNA) sequences have been detected in a sample from a single hair shaft. We have used three different means of DNA typing on these samples: the determination of amplified DNA fragment length differences, hybridization with allele-specific oligonucleotide probes, and direct DNA sequencing.

Patterns of expression of trichocytic and epithelial cytokeratins in mammalian tissues. I. Human and bovine hair follicles

The cytokeratin family of intermediate filament (IF) proteins can be grouped into the epithelial polypeptides ("soft alpha-keratins"), of which at least 19 exist in the various human epithelia, and the hair-type cytokeratins ("hard alpha-keratins"), which are typical of trichocytes, i.e., the living hair-forming cells. We have recently shown [34] that the hair follicles from diverse mammalian species contain a set of eight major cytokeratin polypeptides, four each of the acidic (type I) and the basic (type II) subfamily, which are different from all known epithelial cytokeratins. In addition, we have identified two new minor trichocytic cytokeratin polypeptides, designated Hax (type I) and Hbx (type II). Antibodies against trichocytic cytokeratins that do not crossreact with any of the epithelial cytokeratins have enabled us to study the expression of both kinds of cytokeratin in the various cell types of human and bovine hair follicles. Using immunofluorescence microscopy, we have observed intense reactions of trichocytic cytokeratins only in cells contributing to the forming hairs, i.e., hair shaft, medulla and cuticle, whereas immunostaining of the peribulbar matrix cells was weaker, if at all detectable. In contrast, epithelial cytokeratins were localized in both the inner and outer root sheath epithelia but, surprisingly, also in certain portions of the trichocyte column, notably cells of the cuticle, certain medullary cells, and trichocytes of the basalmost peripapillary cell layers. Cells coexpressing trichocytic and epithelial cytokeratins have been identified by double-label immunofluorescence microscopy. Epithelial cytokeratins of the inner and outer root sheath epithelia include, most remarkably, "simple-epithelium-type" cytokeratins 8, 18, and 19; these occur in certain peribulbar regions, in distinct patterns, but with variable frequencies. The occurrence of simple epithelial cytokeratins in hair follicles has also been confirmed by high-sensitivity immunoblotting of follicular polypeptides separated by gel electrophoresis. Vimentin-positive cells were abundantly interspersed (in some follicles, but not in all) between the trichocytes of the peripapillary cone, most of them probably being melanocytes. The cell-type complexity of the hair follicle and the different patterns of cytoskeletal protein expression in the various hair follicle cells are discussed in relation to the development and growth of this organ.

Methylmercury and the health of autochthons in northwest Quebec

We conducted a cross-sectional epidemiologic and clinical study to evaluate the nature, magnitude, and frequency of unfavourable health states among residents of northwest Quebec. Of particular interest were the possible occurrence of Minamata disease and any other neurological abnormalities. We also sought to determine whether industrial or naturally-occurring mercury in the region's environment were causally associated with any disorders that might be detected. A total of 321 subjects were studied in four groups with contrasting exposure to point-source mercury from a chlor-alkali plant in the area. Methylmercury in hair served as the marker of subject's ingestion of any organic mercury (natural or industrial). Ten pre-chosen target variables, seven clinical and three neurophysiological, were assessed in all subjects. Relationships between mercury in hair and each target variable were calculated. We determined whether gradients in target variables corresponded to gradients in potential exposure of the subjects to the aquatic emissions of the chlor-alkali plant. Minamata disease was not found. Diabetes and alcohol-related health problems assessed as important clinically plausible confounders, were common. Differences in frequency or magnitude of clinical, toxicological, and physiological findings among the contrast groups were small and not of clinical or statistical significance. There were definite relationships between mercury in hair and four target variables despite the low values of mercury measured and the mild nature of the health problems observed. This would suggest that verifiable biological threshold levels for clinical effects, if such exist, may be substantially lower among Canadians than those currently adopted as policy for adults elsewhere. A gradient was found only for two of the ten target variables. Clinically meaningful alternate hypotheses for observed health effects emerge in the data and agree with observations in the field made by consulting clinical experts.

The extraction of high-molecular-mass DNA from hair shafts

A simple and efficient method is presented for the extraction of DNA from hair shafts. DNA preparations obtained by this approach can be made amenable to restriction enzyme digestion, thereby allowing further molecular biological analysis.

Trace elements in human clinical specimens: evaluation of literature data to identify reference values

Reference values are proposed for the concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Pb, Se, and Zn in whole blood, blood serum, urine, milk, liver, and hair from adult human subjects. For F, I, and Ni, it was not possible to evaluate reference intervals for all the specimens mentioned above. For several elements, including Al, B, Br, Cs, Li, Rb, U, and V, the present status of the literature does not provide an adequate basis for formulating baseline concentrations; therefore, results from selected investigations are listed for information only. For elements such as Cu, Fe, and Zn, which are known to be homeostatically controlled, the concentrations in whole blood and blood serum follow a gaussian-like frequency distribution, and we could consider both median and mean values for evaluation. On the other hand, elements whose concentrations in tissues and body fluids are influenced by dietary availability (e.g., As and Se) or environmental factors (e.g., Cd, Hg, and Pb) show wide scatter. In these cases, the median appeared to be a better indicator of the central tendency than the mean, when different populations are involved. These points are illustrated.

Analysis and quantification of pheomelanins by radioimmunoassay

An antiserum against alpha-amino-(4-hydroxy-6-benzothiazolyl)propionic acid (AHBP), a major product obtained after hydriodic acid hydrolysis of pheomelanin, was raised in rabbits immunized with AHBP coupled to bovine serum albumin (BSA). The antiserum was used to develop a radioimmunoassay (RIA) to AHBP. The limit of detection of the RIA is 0.1 ng of AHBP. The antiserum does not crossreact with other major hydriodic acid degradation products, and the assay has been used to estimate the amounts of AHBP in synthetic and natural melanins.

[Effect of roasted wheat flour on the intestinal absorption and zinc metabolism of rats]

24 experiences have been carried in 8 younger Wistar female rats that been submitted to three different diets considering fibers and phytates, with the purpose to demonstrate if "gofio de trigo" of popular consumption in Canary Islands, and rich in these substances affects intestinal absorption of zinc in the diet. Authors have observed a very significant elevation of zinc in feces, during the control period. An important decrease of zinc in hair has been observed indicating a deficit of corporal ion although zinc in serum remained in its normal limit. Authors emphasize the fact that under these circumstances, removal of urinary zinc is not a useful guide for diagnosis of deficiency state.

[Particle induced X-ray emission for trace element analysis of hairs from patients with cancer]

In this paper, trace element analysis of the hairs from the patients with nasopharyngeal carcinoma (NPC) and osteoma was made using particle induced X-ray emission (PIXE) technique in order to obtain some information on the correlation between trace element and these two tumors. The hair samples of 34 NPC patients were each collected before and three months after radiotherapy (60Co) (group 1). The hair specimens from 34 osteoma patients were collected preoperatively and postoperatively. For comparison, 65 hair samples were collected from 40 normal subjects (group 2) and 25 NPC patients, who had received radiotherapy (60Co) five years before without any recrudescence (group 3). The trace element analysis of all specimens was made by PIXE. The results show that there is a significant difference between groups 1 and 2 (P less than 0.01) but no difference is found between groups 2 and 3 for Mn, Cu, Zn, As etc. content in the hairs. Cu and Zn content in the hairs of the osteoma patients is much lower than that of the normal subjects (P less than 0.01) while for K, Ti and Mn content, the former is higher than the latter. The above experimental results are discussed in detail.

Making sense of the hair zinc literature: where do we go from here?

The authors make a critical review on the hair zinc literature, discussing the main contributions in this field. Certain explanations, as well as some solutions aimed to put an end to the confusion which exists on this matter are suggested. As a first step, it is recommended that only endogenous zinc in hair be reliably measured. Therefore, the zinc metabolic status should be operationally defined in function of the zinc detected in hair. Each one of the variables should thus be identified, quantified and controlled. It must be added that these variables would have to include differences in zinc metabolism. Only then would it be possible to see the real baseline reference value of hair zinc. At present researchers should begin looking for a functional relation and not just a statistical significant association between hair zinc concentration and zinc metabolic status. At the same time, it would be necessary to ratify and prove findings of the great number of studies reported in the paper, through the replication of studies with experimental animals.

Zinc deficiency in children with dyslexia: concentrations of zinc and other minerals in sweat and hair

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Effects of feeding selenium deficient diets to rhesus monkeys (Macaca Mulatta)

Pregnant rhesus monkeys (Macaca mulatta) were fed either selenium (Se) deficient or Se supplemented diets with adequate vitamin E. Except for some cardiac irregularities in the first babies born to these females, no physiological disorders due to Se deficiency were seen in a subsequent offspring. Plasma and erythrocyte glutathione peroxidase activities and blood Se levels increased in the Se supplemented monkeys but decreased in the deficient ones. The data indicated that hair Se levels reflect long term exposure to this element. In a very preliminary experiment, evidence was obtained to indicate that dietary protein deficiency along with Se deficiency will generate cardiomyopathic lesions characteristic of Se deficiency. It is hypothesized that, in addition to Se deficiency, another dietary deficiency (or abnormality) is necessary to produce Se deficiency lesions in higher primates. Higher glutathione transferase (or non-Se glutathione peroxidase) activity in tissues of rhesus monkeys may account for this resistance.

Influences of protein malnutrition on amino acid composition, trace metal elements and tensile strength of rat hairs

We examined hair properties from determinations of diameter, amino acid composition, trace metal elements, and tensile strength of the hairs from protein-malnourished rats. The coarse or medium hair diameters of the experimental protein-malnourished rats had a tendency to decrease more than those of the control. Total contents of amino acids in the hairs had a tendency to decrease in the protein-deficient rats. Cystine content of rat hairs definitely decreased only in 5% wheat- and 5% rice-pattern amino acid mixture diet groups but not in 5% gluten diet and 5% casein diet groups. And many of the low-protein diet groups were significantly lower in methionine content than the control except for the 5% casein diet group. The Mg, Zn, and Fe contents in the hairs considerably increased in protein-deficient rats against the control. Tensile strength of coarse hairs in the experimental protein-malnourished rats was significantly lower than that of the control. The changes in amino acid composition of rat hair proteins are more likely to be influenced by various qualities of dietary protein or different compositions of amino acid mixtures in the diets at a similar dietary protein level. It should seriously be considered from our data whether the reduced cystine content in the hair can be regarded as an indicator of nutritional status.

Examinations of ABO bloodgroupings of human hair

In order to bring into play the function of human hair ABO bloodgrouping in the field of medicolegal expertise on material evidence and raise its accuracy, the author, through a test on human hair of 500, makes some emphatic researches on the disposal of hairs, on the application of anti-A and anti-B serum, on the selection of red blood cell indicator and on the elution temperature as well. Five hundred samples of human hair have been examined upon the basis of the improved operation method and through the application of anti-A and anti-B serum, the titer of which being 1:128, and therein, fine results have been obtained.

Hair zinc of young children from rural and urban areas in North Rhine-Westphalia, Federal Republic of Germany

Hair zinc levels were estimated by atomic absorption spectrophotometry in 474 children, aged 3-7 years, from 11 kindergartens in a highly industrialized and polluted area (Duisburg) and 8 kindergartens in a rural area of North Rhine-Westphalia. The mean hair zinc level amounted to 118 micrograms/g, increasing between the 4th and 7th year of life. At all ages the values from the urban toddlers were lower than from rural toddlers, and in both regions they were higher in winter than in summer. Children with frequent upper respiratory tract infections (greater than 6 infections/year) showed significantly lower zinc hair values, independent of their age. Low hair zinc values (below 70 micrograms/g) were frequently found, raising the question as to whether this is a normal, age-related phenomenon, or whether it indicates a suboptimal zinc status of young children from North Rhine-Westphalia.

Determination of manganese in biological materials by electrothermal atomic absorption spectrometry: a review

The great diversity of methods for measuring manganese in biological materials (serum, plasma, whole blood, urine, spinal fluid, and hair) reflects the difficulty in measuring extremely small quantities of this element. Detailed examination of these methods demonstrates that the one most used is flameless atomic absorption spectrometry. In this review we report the different instrument settings for wavelength, slit width, protection gases, graphite furnaces, type of background correction, amounts measured, and thermal programs. We give detailed recommendations by various authors for collecting samples. A thorough description of the preliminary steps and the handling of the specimen samples is also included: direct determination with or without dilution, addition of a matrix modifier or determination after ashing, with or without chelation-extraction steps. The preparation of the standards, procedures used, analytical criteria (accuracy, precision, specificity, detection limit, linearity), problems (interferences, matrix effects), and reference values and their physiological variations are also described. We give a consensus of recommendations concerning the choice of a method.

[Correlation between selenium levels in the human body and lung cancer. II. Multi-statistical analysis of the correlation between selenium levels in the blood, hair, lung and lung cancer]

18 factors, including possible lung cancer-causing factors and body selenium (Se) levels, were analyzed by computer-based multiple stepwise regression and main component analysis. 1. The results indicated that Se levels in blood, hair and lung had correlation with lung cancer to some extent. 2. The correlation of blood and lung Se was the most significant one, the significance of which was only second to age and smoking habits. The standardized regression and factor load coefficients showed a negative correlation with blood Se level and a positive one with lung Se level, which corresponded with the results obtained by the single factor analysis.

Variables influencing cadmium concentrations in hair of pre-school children living in different areas of the Federal Republic of Germany

The influence of several factors on cadmium (Cd) concentrations in the hair of 474 pre-school children was examined. The study was performed in an industrial (Duisburg) and rural area (Westfalen) of the (FRG). Season, sex, hair color, and place of residence were found to be the main factors influencing Cd levels in hair. Concentrations of Cd in samples obtained during summer were on the average nearly twice as high as those sampled during winter (geometric means: 116.1 vs. 63.7 ng/g). Boys had more Cd in their hair than girls (111.5 vs. 74.0 ng/g). Cd levels in hair decreased from red to blond, to brown, and black hair. Children living in Duisburg had more Cd in their hair than those from rural areas (103.9 vs. 77.0 ng/g). Cd content in hair was inversely related to age.

Diagnostic value of zinc concentrations in serum, leucocytes and hair of dogs with zinc-responsive dermatosis

The concentrations of zinc in serum, leucocytes and hair of normal dogs, dogs with zinc-responsive dermatosis and dogs with dermatitis not associated with zinc deficiency was determined. The mean concentration of zinc in serum and hair of dogs with zinc-responsive dermatosis was significantly lower than in other dogs but the range of zinc concentrations overlapped that of the other dogs. The mean leucocyte zinc concentration was similar for each group of dogs. It is concluded that low zinc concentrations in serum and hair have only a corroborative value in the diagnosis of zinc-responsive dermatosis in dogs.

Effects of prolonged duct ligation of the rat salivary glands on the activity of trypsin-like protease

The effects of ligation on body weight, protease activity and hair kynurenine content were observed. The body weights of parotid gland(PT)-ligated and of combined submandibular (SM)-, sublingual (SL)- and PT-ligated rats were much less than those of sham-operated controls. However, the weights of SM,SL-ligated rats were similar to those of controls. The activity of trypsin-like protease in the duct-ligated submandibular gland was significantly reduced to 0.3-0.7 per cent of that in controls. Protein concentration also decreased in the duct-ligated submandibular gland. Kynurenine content in the hair of duct-ligated rats was higher than that in controls.

Hair analysis as an indicator of mineral status of livestock

Despite several inherent characteristics that would appear to make hair a useful biopsy tissue, many problems make interpretation of data derived from hair analysis difficult. Endogenous minerals are incorporated into hair by several routes. Most attention on hair mineral incorporation has focused on element uptake within the hair follicle. Minerals incorporated within the follicle are presumably chemically or physically associated with cortical cells of the hair shaft and reflect mineral status at the time that the hair filament was synthesized. Because hair follicles in most species regularly go through cycles of intense metabolic activity and quiescence, mineral incorporation through the follicle is not a continual process. Mineral deposition onto hair does not cease when the follicle is not producing a hair fiber. The hair shaft is continuously exposed to several elements through contact with secretions from sebaceous, apocrine and eccrine glands. Significant quantities of major and trace elements of endogenous origin are adsorbed onto the hair surface via these secretions, especially when hair growth is not occurring or is very slow. For several elements significant correlations exist between mineral concentrations in hair and mineral intake. These correlations, however, are usually quite low. Non-dietary factors such as sex, age, hair color, sire, body location and contamination affect mineral levels in hair. Dietary intake of calcium, phosphorus and iron are also known to affect uptake of other elements in hair. Because many factors cause variation in mineral content in hair, hair analyses are not precise indicators of mineral status. Hair mineral analyses may be useful, however, when combined with other indicators of mineral status to provide a more precise assessment of mineral status in livestock.

Determination of zinc pyrithione in cosmetic products by high-performance liquid chromatography with pre-labelling

A high-performance liquid chromatographic (HPLC) method has been developed for the determination of zinc pyrithione (Zpt) in commercial cosmetic products. Zpt was pre-labelled with N-dansylaziridine and determined by reversed-phase HPLC. Ingredients in cosmetic products did not interfere in the pre-labelling reaction. The calibration graph for Zpt was linear in the range 1.4-66 ng. The coefficient of variation was 0.9% for 17-ng injections. Using the proposed method, Zpt in commercial cosmetic products was determined with high sensitivity and high selectivity. The proposed method is also applicable to the determination of trace amounts of Zpt adsorbed on human hair.

[Heavy metal content of the children's hair]

In the framework of the epidemiological group-diagnostic studies in the industrial areas Rhine-Main (Wiesbaden and Frankfurt) with a relatively high air pollution as well as in two control areas (Freiburg and Starnberg) with lower air pollution, hair samples from more than 2500 ten-year-old children were taken. After an appropriate washing process (removal of the exogenic load) and wet incineration, the hair samples were examined by AAS- for their heavy metal content (Cd, Pb, Fe and Zn). The evaluation of the results over the time of the examination from 1982 until 1986 shows that the hair samples from children in the burdened area Rhine-Main with high air pollution have higher lead as well as cadmium values than those of the control area Freiburg with the bordering region of the Black Forest. Furthermore it can be clearly recognized in the five years of the examination of children's hair that the contamination or the content of toxic heavy metals such as Cd and Pb in the polluted region of Wiesbaden is distinctly decreasing over the years. Surprisingly, increased zinc, cadmium and also, during the last two years, increased lead values in children's hair were detected in the Starnberg area. During the five years of examination there was a correlation between the heavy metal content in children's hair and the heavy metal content in airborne dust of the burdened area; this is particularly true for cadmium.

[Strategy of environmental medical research]

A report is made on the strategy and tactics of an environmental medical, group-diagnostic study of children which was carried out by order of the Hessian Minister of Social Security within the framework of the Lufreinhalteplan (Clean Air Plan) Rhine/Main in the time from 1982 to 1986. This is a group-diagnostic examination of ten-year-old healthy children in the burdened area Rhine/Main (Wiesbaden, Frankfurt) and in the control areas of Freiburg and Starnberg. The objective of the study is to register the influence of the environment, in particular of air pollution, on a portion of the child population, especially with regard to persons at risk who react particularly sensitive to environmental influences and/or who have special health problems. In this connection it is attempted to convert the measuring data collected for characterizing the environment (ambient air) into effect-oriented data. The targets examined, i.e. anthropometric and clinical examinations as well as microbiological, immunologic and haematologic tests and the analysis of hair are to be evaluated in addition to family and social factors. Beyond that the attempt is made to correlate the results of the study with the biometeorological effective variables.