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At least 19 recordsLinked to original sources
PubMed1989

Magnesium-to-calcium ratio in tap water, and its relationship to geological features and the incidence of calcium-containing urinary stones.

We examined the relationship among magnesium and calcium content in tap water, the geological features and urinary stone incidence in Japan. The magnesium-to-calcium ratio in tap water correlated negatively with the incidence of urolithiasis. There was no correlation between calcium and magnesium concentration in tap water and urinary stone incidence. Geological features in Japan were classified into 5 groups. The magnesium-to-calcium ratio in the basalt areas was higher than in the other areas, while ratio in the granite areas was low. In the sedimentary rock areas calcium and magnesium concentrations were high; the magnesium-to-calcium ratio in these areas was between those of the basalt and granite areas. The limestone areas had a much higher calcium concentration. The incidence of urinary stones in the sedimentary rock and basalt areas was lower than that of the granite areas, while that in the limestone areas was the highest. Thus, the incidence of urinary stone is related to the magnesium-to-calcium ratio in tap water and the geological area.

Calcium↗
PubMed1991

Waterborne outbreak of Norwalk virus gastroenteritis at a southwest US resort: role of geological formations in contamination of well water.

From April 17 to May 1, 1989, gastroenteritis developed in about 900 people during a visit to a new resort in Arizona, USA. Of 240 guests surveyed, 110 had a gastrointestinal illness that was significantly associated with the drinking of tap water from the resort's well (relative risk = 16.1, 95% confidence interval 14.5 to 17.8) and this risk increased significantly with the number of glasses of water consumed (p less than 0.005). Three of seven paired sera tested for antibodies to the Norwalk agent had a four-fold or greater rise in titre. Water contaminated with faecal coliforms was traced back to the deep water well, which remained contaminated even after prolonged pumping. Effluent from the resort's sewage treatment facility seeped through fractures in the subsurface rock (with little filtration) directly into the resort's deep well. Although the latest technology was used to design the resort's water and sewage treatment plants, the region's unique geological conditions posed unexpected problems that may trouble developers faced with similar subsurface geological formations and arid climatic conditions in many parts of the world. In these areas, novel solutions are needed to provide adequate facilities for the treatment of sewage and supply of pure drinking water.

Cohort Studies↗
PubMed1990

Voltammetric determination of platinum in inorganic complexes and in water, geological and biological matrices using laboratory- and field-based instrumentation.

The extremely sensitive catalytic hydrogen ion reduction wave observed after the formation of a platinum-formazone complex at a mercury electrode in a hydrazine-formaldehyde-H2SO4 medium has been utilised to determine platinum voltammetrically in well characterised platinum inorganic complexes (oxidation states O, II and IV) and in biological, geological and water samples. Experimental conditions have been optimised and sample-treatment procedures for various matrices have been critically evaluated for the quantification of platinum by the standard additions method. The determination of platinum in geological samples by this method has been compared with an inductively coupled plasma mass spectrometric method. Both conventional and portable field-based instrumentation have been used in the studies, and the possibility of developing a field-based method for the determination of platinum has been investigated. Despite the inherent sensitivity of the method, which enables concentrations down to 0.01 p.p.b. to be detected in simple matrices, natural levels in water and biological materials, where matrix effects suppress the voltammetric response, are often below the detection limit.

Animals↗
PubMed1989

Indoor Rn levels in different geological areas in Switzerland.

The distribution of indoor Rn concentrations in different geological areas in Switzerland was studied using passive alpha-track detectors. Measurements involving a sample of 400 single-family homes were made in the cellar, on the ground floor and the first floor, respectively. On the basis of a pilot survey, the country was divided into four zones in which the Rn distribution in houses was analyzed separately. The indoor exposure to Rn and Rn decay products is quite variable from region to region. The geology of the different areas was found to be an important factor in determining the mean value Rn levels. In the basin north of the Alps, where the population centers are located, a median Rn gas level of 47 Bq m-3 for the living area was found. The arithmetic mean value of 60 Bq m-3 in this region leads to an annual effective dose equivalent of about 1.8 mSv. For the population living in alpine areas, an arithmetic mean value exceeding 200 Bq m-3 will lead to an annual effective dose equivalent in the range of 6 mSv. The estimated exposure to Rn and Rn decay products for the upper one-percentile of the homes in the most affected alpine region even exceeds the annual limit of 50 mSv effective dose equivalent for occupational exposure.

Air Pollutants↗
PubMed1991

Characterisation of palygorskite specimens from different geological locales for health hazard evaluation.

Palygorskite, a fibrous clay mineral, is being used as a substitute for asbestos in some applications. Nine specimens obtained from different geological locales were studied for mineral purity, elemental composition, fibre size distribution, and surface binding characteristics. The membranolytic activity of each was determined using a human erythrocyte model. The membranolytic behaviour and surface binding characteristics were compared with three chrysotile specimens employed as positive controls. The palygorskite specimens derived from the different geological locales display a range of physicochemical properties. This study shows the importance of selecting several mineral specimens for a health hazard evaluation. The current carcinogenic classification of the mineral may be limited due to the number of specimens used for that particular evaluation.

Asbestos↗
PubMed1989

Differences in cancer mortality rates in Ohio communities with respect to uraniferous geology.

Populations in areas of uraniferous geology may be at risk from radon emissions. Twenty-eight municipalities were examined as to their location with respect to uraniferous geology. Communities with possible radon risk had higher rates for all cancers and cancer of the respiratory system, but differences were not statistically significant. Some possible reasons for the results are discussed.

Geological Phenomena↗
PubMed1992

Comparative variation of morphological and molecular evolution through geologic time: 28S ribosomal RNA versus morphology in echinoids.

The comparatively good fossil record of post-Palaeozoic echinoids allows rates of morphological change to be estimated over the past 260 million years and compared with rates of molecular evolution. Parsimony analysis of morphological data, based predominantly on skeletal characteristics, and parsimony, distance and maximum likelihood analyses of molecular data, from the first 380 bases from the 5' end of the 28S rRNA molecule, for 10 species of echinoid produce congruent phylogenies. The molecular sequence chosen is demonstrably far from saturation and sister groups have divergence times ranging from about 15 to 260 Ma. Parsimony analysis allows the great majority of molecular and morphological apomorphies to be placed in one of 18 independent geological time intervals, providing a direct measure of rates of evolution for periods in the geological past. Because most molecular fixed point mutations in our sequences cannot be polarized unambiguously by outgroup comparison (making the outgroup states effectively random), distance and parsimony analyses both tend spuriously to root the echinoid tree on the longest internal branch. A topology identical to that derived from morphological data is, however, obtained using Maximum Likelihood and also parsimony analysis where outgroup rooting is restricted to more conserved regions. This is taken as the correct topology for assessing rates of evolution. Overall, both morphological and molecular changes show a moderately strong correlation with time elapsed, but a weaker correlation with one another. Statistically significant differences in evolutionary rate are found between some, but not all, pair-wise comparisons of sister lineages for both molecular and morphological data. The molecular clock rate for echinaceans is three times faster than that for cidaroids and irregular echinoids. Spearman's rank correlation test, which requires only relative magnitude of changes to be known, suggests that morphological change has a slightly better correlation with time than does molecular change, averaged over all ten species. However, when just echinaceans are considered an extremely good correlation is found between the number of molecular changes and time elapsed, whereas morphological change remains poorly correlated. Thus, molecular rates approximate to a clocklike model within restricted echinoid clades, but vary significantly between clades. Averaging results over all echinoids produces a correlation that is no better than the correlation between morphological change and time elapsed.

Animals↗
PubMed1990

A sick house syndrome, possibly resulting from a landfill geologic effluvia.

A novel indoor air quality investigation was associated with carbon dioxide and methane accumulation, presumably from effluvia from geologic sources. Each of 6 workers in an office building complained of respiratory symptoms, and of difficulty with memory and concentration in the workplace, a tightly-sealed structure under negative pressure. No single contaminant was identified to explain the clinical syndromes. No detectable levels of carbon monoxide, methyl ethyl ketone, formaldehyde, ozone, carbon disulfide, nitric oxide, ethylene oxide, ammonia, aldehydes, trichloroethylene or similar chlorinated compounds were found. Carbon dioxide and methane were both present at above ambient outdoor air concentrations. Carbon dioxide was documented to accumulate over a weekend with no occupants in the building, suggesting a geologic source.

Adult↗
PubMedDate not supplied

Prebiotic nucleotide synthesis-demonstration of a geologically plausible pathway.

Mineral phosphate (apatite) is activated for the synthesis of nucleotides when dilute solutions containing nucleoside and ammonium oxalate are evaporated in its presence. A natural, igneous fluorapatite was found to be even more effective in nucleotide synthesis than the more soluble hydroxylapatite. The phosphorylation is considerably more efficient if urea of cyanamide is also present. Hydrolysis of solutions of cyanogen to form oxalate and urea among other products is a spontaneous process that provides a geologically plausible model for necleotide synthesis on the primitive earth.

Apatites↗
PubMed1989

Influence of subsoil geology and construction technique on indoor air 222Rn levels in 80 houses of the central Swiss Alps.

The indoor 222Rn level depends mainly on the subsoil geology, the cellar floor permeability, the cellar aeration, the air-tightness of the homes, and the aeration habits of the occupants. These five parameters and the 222Rn levels in the cellar and in the living room on the ground floor were compiled in 80 one- or two-family houses of the central Swiss Alps. The 222Rn levels were measured with passive alpha track detectors. Houses located on a granite, ortho-gneiss or verrucano subsoil have a cellar 222Rn level that is on the average 4.4 times higher than houses which are built on grey-schist or sediments. The cellar level is on the average 5.4 times higher if the cellar has partially a gravel or earth floor than if the whole cellar surface is covered with a concrete floor. Energy-efficient, highly air-tightened homes have a living room level that is on the average 1.8 times higher than normally insulated conventional homes. In the cellars and the living rooms of the 80 houses considered, arithmetic mean 222Rn levels of 724 Bq m-3 (20 pCi L-1) and 178 Bq m-3 (4.8 pCi L-1), respectively, were found. In the central Swiss Alps 222Rn and 222Rn decay products lead to an estimated mean exposure of 5.3 mSv effective dose equivalent per year.

Air Pollutants↗
PubMed1992

The early evolution of eukaryotes: a geological perspective.

Molecular phylogenies of eukaryotic organisms imply patterns of biological and environmental history that can be tested against the geological record. As predicted by sequence comparisons, Precambrian rocks show evidence of episodic increases in biological diversity and atmospheric oxygen concentrations. Nonetheless, complete integration of the two records remains elusive and may require that the earliest macroscopic organisms be recognized as extinct experiments in eukaryotic multicellularity.

Biological Evolution↗
PubMed1991

Determination of radium isotope ratios and abundances in geologic samples by thermal ionization mass spectrometry.

We describe chemical separation and mass spectrometric procedures for the measurement of radium isotopes in geologic samples. These methods provide 226Ra/228Ra ratio measurements for 1 g or less of rock sample containing subpicogram amounts of radium with precision better than 1.5% (95% confidence level). Radium-226 concentrations were measured by isotope dilution for smaller sample sizes (100-500 mg) containing as little as 1-10 fg of total 226Ra with similar high precision.

Geology↗
PubMed1991

[A hygienic assessment of the noise and vibration from the machines and engines used in geological survey operations and the measures to decrease the adverse action of these factors on workers' bodies].

In the last 10 years, no decrease in noise and vibration conditions has been registered at a geological survey enterprise. On the contrary, the introduction of new, more productive equipment caused increase in the indices. The unfavourable labour conditions have resulted in higher occupational morbidity levels caused by the otic nerve neurites. The article sets forth a package of measures towards minimizing the hazardous influence of noise and vibration on the workers' health status.

Absenteeism↗
PubMedDate not supplied

Instrumental neutron activation analysis of geological and biological reference materials using the ko-standardization method.

The ko-standardization method used in instrumental neutron activation analysis (INAA) was applied to the determination of some elements in geological and biological reference materials. We analyzed NBS SRM 1572 Citrus Leaves and SRM 1645 River Sediment and the CRM materials, IAEA Soil-7, SL-1, and MA-A-2. Comparison is made with reference values whenever available. Good agreement is found. The potential of the ko-standardization method in reactor INAA is discussed.

Animals↗
PubMed1989

Geology, trace elements and health.

Both animal and vegetable life depend for their existence on appropriate amounts of various trace elements, albeit in very small amounts. This paper lists some of these trace elements and the ailments in which they play an important role. The elements discussed are gold, platinum, copper, lead, zinc, aluminium, silica, mercury, cadmium, selenium, arsenic, and iodine. The diseases involved range from multiple sclerosis, various cancers, arthritis, goitre, Down's Syndrome, and mental retardation. Less well known are Keshan, Alzheimer's, Itai-Itai, and Minamata diseases. Of particular interest in the latter part of the twentieth century is the discovery that serious deficiencies of either copper or zinc in the diet of animals may break down their immune defence mechanisms. The ability of certain plants selectively to concentrate particular heavy metals in their tissues and pollen is discussed.

Geological Phenomena↗
PubMed1987

Sepiolite asbestos from Franklin, New Jersey: a case study in medical geology.

Asbestiform sepiolite has been found in a zinc deposit at Franklin, New Jersey. The host rock is Precambrian Franklin marble. Pseudomorphous foliated texture and cross-cutting relationships indicate replacement of talc by sepiolite. Sepiolite is manganoan, while talc contains little manganese, suggesting differences in manganese substitution in these minerals and providing evidence against solid-state replacement. Sepiolite from Franklin is of moderate crystallinity and consists of soft, flexible mass-fiber. Comparison with other sepiolite samples suggests that increased crystallinity among sepiolites parallels increased fiber length, while disorder appears to be associated with flexibility. Length and aspect ratio (length/width) distributions support toxicological equation of asbestiform sepiolite with the regulated asbestos minerals. The data presented here suggest that talc can be unstable in a low-temperature hydrothermal environment, altering under certain conditions to form sepiolite. In a wider context, sepiolite may be expected to precipitate at the end-stages of hydrothermal mineralization in some talc deposits and in carbonate and calc-silicate rocks. Many occurrences of sepiolite in these rocks may have been overlooked due to similarities with other minerals. The fact that sepiolite has been previously unrecognized and misidentified at Franklin is a case in point. Since there is evidence suggesting that sepiolite is fibrogenic and carcinogenic, its potential occurrence in consumer talcs and crushed-stone products has environmental health implications. Similarities in composition and other analytical parameters may cause sepiolite to be mistaken for fibrous talc or chrysotile in environmental samples.

Geological Phenomena↗
PubMed1975

The influence of stream geology on the distribution of the bilharzia host snails, Biomphalaria pfeifferi and Bulinus (physopsis) sp.

The Gladdespruit and Komati River surveys have shown that similar environmental conditions have developed where the watercourses flowed over particular rock types. In these watercourses a potentially useful association was found between the occurrence of permanent, lentic habitats produced by the weathering of bedrock with a hardness above 5 in Mohs' Scale of Hardness and the longitudinal distribution of persistent populations of the bilharzia intermediate host snails Biomphalaria pfeifferi and Bulinus (Physopsis) sp. Bilharzia transmission follows this pattern in these waterways. Weathering of bedrock with hardness below 5 in Mohs' scale, and/or flow over beds of alluvial sand, produced perpetually lotic (flowing) environments without persistent host snail populations because of the snail's inability to tolerate high current speeds. However a few temporary populations survived in temporarily lentic habitats during the dry winter season.

Africa↗