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1.
The south-west of England was designated by the National Radiological Protection Board (NRPB) as the first ‘Radon Affected
Area’, as over 1% of the housing stock is estimated to have an indoor radon concentration in excess of the 200 Bq m−3 Action Level. The situation is even worse for houses situated above uraniferous granite intrusions, where over 30% are thought
to be above the Action Level.
The aim of this study is to investigate the relationship between the level of radon in soil gas and the local geology. Particularly
high radon levels were measured along major fault zones. This could be explained by: increased rate of migration of the radon
due to the permeable fault, the presence of radium or radon-bearing ground water within the fault, or secondary uranium mineralisation.
Seasonal variations are also considered. 相似文献
2.
Radu Lacatusu Corneliu Rautal Constantin Grigore Stelian Cârsteal Ileana Ghelasel 《Environmental geochemistry and health》1993,15(1):3-13
Haematuria-inducing areas in the northern and central parts of the Eastern Carpathian Mountains are characterised by the mesozoic-crystalline, neogene eruptive and transcarpathian flysch zones. The rocks have high concentrations of some metals and radioactive elements, some of them bearing polymetallic sulphides. The soils are strongly or moderately acid and oligomesobasic. They have a deficiency of soluble phosphorus and molybdenum, but up to 4.9 times the background content of metallic elements in non-affected zones. The waters have a pH around 7, a low content of salts (0.09–0.62 g L–1), but metal levels in excess of 10 times that of the background level. Pasture vegetation has a low nutritional value, and includes up to 12% of poisonous plant species. It is characterised by low total concentrations of P, Mo, N and K, and high total concentrations of metallic trace elements, including high values of Zn and excessive values of Fe, Mn, Pb, Cr, Ni, Cd and Al. Besides clinical symptoms specific to haematuria, sick animals have abnormal blood and urinary compositions and specific morphopathological features. High concentrations of metallic elements were detected in renal calculi. The correlation of the geochemical and biogeochemical features of the haematuria-inducing areas, together with the results of the epizootological, clinical, paraclinical and morphopathological research emphasises that chronic cattle haematuria is a disease with numerous causes, but is primarily a biogeochemical problem in the area studied, making it an ecosystem disease.To whom correspondence should be addressed. 相似文献
3.
Radon has been determined in soil, groundwater, and air in Mexico, both indoors and outdoors, as part of geophysical studies
and to estimate effective doses as a result of radon exposure. Detection of radon has mainly been performed with solid-state
nuclear track detectors (SSNTD) and, occasionally, with active detection devices based on silicon detectors or ionization
chambers. The liquid scintillation technique, also, has been used for determination of radon in groundwater. The adjusted
geometric mean indoor radon concentration (74 Bq m−3) in urban developments, for example Mexico City, is higher than the worldwide median concentration of radon in dwellings.
In some regions, particularly hilly regions of Mexico where air pollution is high, radon concentrations are higher than action
levels and the effective dose for the general population has increased. Higher soil radon levels have been found in the uranium
mining areas in the northern part of the country. Groundwater radon levels are, in general, low. Soil-air radon contributing
to indoor atmospheres and air pollution is the main source of increased exposure of the population. 相似文献
4.
The concentration of uranium was determined in 944 samples from stream water by the inductively coupled plasma quadrupole
mass spectrometry (ICP-QMS) method and represented on a color-shaded contour map. Uranium concentrations in surface water
were determined to be between 0.007 μg/l and 43.7 μg/l with median of 0.33 μg/l. The regional distribution of uranium is influenced
primarily by lithological and anthropogenic factors. In Mecklenburg, northern Brandenburg, and eastern Schleswig-Holstein,
elevated uranium concentrations coincide with the extent of the last Weichselian ice sheet. The maximum concentrations are
observed in the surface waters of the old mining districts in the western part of the Ore Mountains and in eastern Thuringia.
Elevated concentrations are found in areas of agriculturally used loess soils. These concentrations correlate with the use
of phosphate fertilizers. There is a zone of elevated concentrations up to 10.0 μg U/l in the Keuper Sandstone area south
of the Thuringian Forest and from northwest of Stuttgart as far as Coburg. The distribution of elevated values in mineral
water shows a clear correlation with the elevated values in surface water and the geology of those locations. Bunter and Keuper
strata are the most important uranium source. 相似文献
5.
Abdel Ghany HA 《Environmental geochemistry and health》2007,29(3):249-255
Radium-226 is a significant source of radon-222 which enters buildings through soil, construction materials or water supply.
When cigarette smoke is present, the radon daughters attach to smoke particles. Thus, the alpha radiation to a smoker’s lungs
from the natural radon daughters is increased because of smoking. To investigate whether the cigarette tobacco itself is a
potential source of indoor radon, the α potential energy exposure level contents of radon (222Rn, 3.82d) and Thoron (220Rn, 55.60s) were measured in 10 different cigarette tobacco samples using CR-39 solid-state nuclear track detectors (SSNTDs).
The results showed that the 222, 220Rn concentrations in these samples ranged from 128 to 266 and 49 to 148 Bqm−3, respectively. The radon concentrations emerged from all investigated samples were significantly higher than the background
level. Also, the annual equivalent doses from the samples were determined. The mean values of the equivalent dose were 3.51
(0.89) and 1.44 (0.08) mSvy−1, respectively. Measurement of the average indoor radon concentrations in 20 café rooms was, significantly, higher than 20
smoking-free residential houses. The result refers to the dual (chemical and radioactive) effect of smoking as a risk factor
for lung cancer. 相似文献
6.
To examine the suitability of benthic foraminifera and their test deformations as bioindicators of pollution in coastal marine environments, we studied foraminifera and metal concentrations in 72 marine sediment samples, collected from the inner shelf along the Sicilian coast (Gulfs of Palermo and Termini) and on the south-eastern coast of Lampedusa Island. These areas are characterised by different environmental conditions. On the basis of pollution sources and foraminiferal assemblages, we recognised different zones in the Gulf of Palermo. The most polluted zones showed high metal concentrations, and low diversity of benthic foraminifera with species typical of stressed environments. By contrast, the lowest polluted zones showed a high population density and the highest percentages of epiphytes. Epiphytes were abundant where a Posidonia oceanica meadow was present and decreased in the most polluted zones. Sediments of the Gulf of Termini and Lampedusa exhibited high percentages of benthic foraminifera typical of well-oxygenated waters and low concentrations of metals, with the exception of sites located near sewage outfalls and harbour areas. Furthermore, even though deformed tests are commonly known in natural stressed environmental conditions, this study shows that in the most polluted zones, benthic foraminifera were characterised by the highest percentages of deformed individuals. 相似文献
7.
Relatively low concentrations of fluorine in drinking water ( 1 mg F/l) have been shown to significantly reduce the degree of dental caries in children and fluorine would also appear to have a beneficial effect on bone formation in both humans and farm animals. However, it is apparent that elevated levels of fluorine in the diet have sometimes resulted in problems of increased dental caries and of the development of bone deformities. Much of the fluorine in rocks and soils occurs in apatite and hydroxysilicate minerals, fluorite being the only relatively common rock forming mineral containing fluorine as an essential constituent.Little systematic data are available on fluorine concentrations in soils, plants and natural waters in the UK. General background soil concentrations lie in the range 200 – 400 mg F/kg. For waters the average fluorine content is low, <0.1 mg F/l.In the British Isles there are several areas where there are enhanced levels of fluorine. In the northern Pennines, Derbyshire, northeast Wales and Cornwall, fluorite occurs as a significant component of mineralisation and much fluorine has been added to the environment from mining waste dumps. Soils in northeast Wales contain up to 3,650 mg F/kg and in the northern Pennines up to 20,000 mg F/kg. Waters contain up to 2.3 mg F/l. In southwest England, the granites are generally fluorine-rich with the fluorite granites of the St Austell pluton containing as much as 1 percent fluorine. These rocks are frequently kaolinised and intensively worked as a source of china clay. Soils in the vicinity of the waste tips contain up to 3,300 mg F/kg and grasses up to 2,950 mg F/kg. Surface waters in the St Austell area contain up to 1.25 mg F/l.Atmospheric fluorine pollution around brickworks in the Peterborough and Bedford areas has resulted in fluorosis in farm animals. Other sources of atmospheric fluorine pollution are aluminium smelters, steelworks and fossil fuel burning. 相似文献
8.
John Maskall Keith Whitehead Iain Thornton 《Environmental geochemistry and health》1995,17(3):127-138
The vertical migration of metals through soils and rocks was investigated at five historical lead smelting sites ranging in age between 220 and 1900 years. Core samples were taken through metal-contaminated soils and the underlying strata. Concentration profiles of lead and zinc are presented from which values for the distances and rates of migration have been derived. Slag-rich soil horizons contain highly elevated metal concentrations and some contamination of underlying strata has occurred at all sites. However, the amounts of lead and zinc that have migrated from soils and been retained at greater depths are comparatively low. This low metal mobility in contaminated soils is partly attributed to the elevation of soil pH by the presence of calcium and carbonate originating from slag wastes and perhaps gangue minerals. Distances and rates of vertical migration were higher at those sites with soils underlain by sandstone than at those with soils underlain by clay. For sites with the same parent material, metal mobility appears to be increased at lower soil pH. The mean migration rates for lead and zinc reach maxima of 0.75 and 0.46 cm yr–1 respectively in sandstone at Bole A where the elements have moved mean distances of 4.3 and 2.6 m respectively. There is some evidence that metal transport in the sandstone underlying Bole A and Cupola B occurs preferentially along rock fractures. The migration of lead and zinc is attenuated by subsurface clays leading to relatively low mean migration rates which range from 0.03 to 0.31 cm yr–1 with many values typical of migration solely by diffusion. However, enhanced metal migration in clays at Cupola A suggest a preferential transport mechanism possibly in cracks or biopores. 相似文献
9.
Anthony D. Cak Emilio F. Moran Ricardo de O. Figueiredo Dengsheng Lu Guiying Li Scott Hetrick 《Journal of Land Use Science》2016,11(2):203-221
Many small watersheds and streams in the Brazilian Amazon have been impacted by agriculture and urban development, often due to household economic needs and migration processes. This study examined the relationships between land use, soil type, and household factors on stream water chemistry in and near the city of Altamira, Pará, Brazil, in 2008–2009. While soil weathering and stream discharge may have affected several stream water ion concentrations, agriculture and especially urban development were associated with high dissolved nitrogen concentrations, high water temperatures, and low dissolved oxygen concentrations in streams. Younger interviewed households were generally associated with these watersheds, and many urban residents reported disposing of household waste directly into streams. In contrast, older households were generally associated with forest and cocoa agriculture, along with lower water temperatures and higher dissolved oxygen concentrations in streams. These conditions persisted despite reported uses of herbicides and fertilizers by some residents. 相似文献
10.
Characterization of environmental water samples using strontium and lead stable isotope compositions
A simple procedure using both cation and anion exchange chromatography has been applied in the study of lead and strontium isotope composition in rain and stream water samples from remote catchments in Scotland. Whereas the soil released strontium to stream waters, lead was removed from rain water and the concentrations in stream waters were very low. Highly precise analysis by thermal ionisation mass spectrometry proved necessary in the determination of strontium isotope composition. The 87Sr/86Sr ratio in rain water was close to that of marine strontium but the ratios in stream waters were constant and highly characteristic for the stream. In the case of the stream at the Sourhope site, the ratio (0.70798 ± 0.00005) was less than that in rain water and probably resulted from the weathering of one specific mineral. The results suggested that the 87Sr/86Sr ratios could be used as a stable isotope tracer of waters and to provide information on the weathering processes. Two major anthropogenic components of lead were identified in water samples. One had its origin in petrol additives whereas the other was probably of industrial origin. The low 206Pb/207Pb ratios observed in stream waters confirmed the lead as being of anthropogenic origin and the data suggested that there was a movement, albeit very small, of lead from the soil to waters. 相似文献
11.
A comparison of metals in sediments and water in the River Nahr-Ibrahim,Lebanon: 1996 and 1999 总被引:1,自引:0,他引:1
Rivers whose basins are underlain by carbonate rocks exhibit high pH, lower desorption of metals and possess high buffering capacity against acidic inputs to the river. The catchment of River Nahr-Ibrahim, Lebanon, is largely underlain by limestone. Compared to neighbouring countries, Lebanon is relatively fortunate since precipitation is high. However, recently a warming in temperature and a drop in precipitation has occurred, thus causing low water levels in rivers. The objective of this study is to investigate the variation of the total metal content (Fe, Mn, Zn, Cu, Pb and Cd) in bed sediments and water of River Nahr-Ibrahim between 1996 and 1999 (two years); and relate these variations to the effect of changes in human activities and/or due to the variations of precipitation rate, temperature and pH of water. Bed load sediments and stream water were collected simultaneously from five sampling sites. Water pH and temperature were determined in situ. Sediment samples were dried at room temperature and sieved; the sediment size <75 m size was retained. Water was analysed for major constituents and trace metals. Metals were extracted from sediments with aqua regia. Metal concentration in water and sediments were determined using ICP-MS technique. Data revealed a drop in metal concentrations (Zn, Cu, Pb, Cd) in sediments at quarry site after its closure. The decrease in precipitation rate, lowering the level of water and the dilution of industrial discharges and decrease in water pH led most probably to the desorption of metals from sediments into the water. 相似文献
12.
Efficient phytoremediation of uranium mine tailings by tobacco 总被引:1,自引:0,他引:1
Mirjana D. Stojanovi? Marija L. Mihajlovi? Jelena V. Milojkovi? Zorica R. Lopi?i? Milan Adamovi? Slavka Stankovi? 《Environmental Chemistry Letters》2012,10(4):377-381
This investigation shows that tobacco plant roots and leaves accumulate 60?times more uranium than previously reported. Phytoremediation is a convenient technique to clean up polluted soils using herbaceous plants and trees. Increasing research aims to identify novel plant species that accumulate toxic metals. Tobacco plant (Nicotiana tabacum L.) is a promising cultivar for phytoremediation because tobacco is fast growing and easily propagated. Here, we study phytoremediation of uranium by two tobacco varieties Virginia and Burley, bred in natural conditions. Plants were grown on uranium mine tailings with an average uranium content of 15.3?mg?kg?1. Each shoot sample was cross-sectioned into five uniform groups of leaves and stem segments. Results show a substantial variance in uranium uptake according to the section elderliness and origin of the plant parts. The highest concentrations of uranium values recorded in leaves of Burleys and Virginias nearest root shoot sections were 4.18 and 3.50?mg?kg?1, respectively. These values are 60?times higher rates than those previously published for leaves of cultivars grown under similar conditions. Taking into account the level of soil contamination, the content of accumulated uranium demonstrates uranium hyperaccumulatory properties of tobacco plant and its potential utilization in phytoremediation of uranium-contaminated mediums. 相似文献
13.
G. L. Carneiro D. Braz E. F. de Jesus S. M. Santos K. Cardoso A. A. Hecht Moore K. Dias da Cunha 《Environmental geochemistry and health》2013,35(3):333-340
The aim of this study was to evaluate the public and occupational exposure to radon and metal-bearing particles in museums and public buildings located in the city of Rio de Janeiro, Brazil. For this study, four buildings were selected: two historic buildings, which currently house an art gallery and an art museum; and two modern buildings, a chapel and a club. Integrated radon concentration measurements were performed using passive radon detectors with solid state nuclear track detector-type Lexan used as nuclear track detector. Air samplers with a cyclone were used to collect the airborne particle samples that were analyzed by the particle-induced X-ray emission technique. The average unattached-radon concentrations in indoor air in the buildings were above 40 Bq/m3, with the exception of Building D as measured in 2009. The average radon concentrations in indoor air in the four buildings in 2009 were below the recommended reference level by World Health Organization (100 Bq/m3); however, in 2011, the average concentrations of radon in Buildings A and C were above this level, though lower than 300 Bq/m3. The average concentrations of unattached radon were lower than 148 Bq/m3 (4pCi/L), the USEPA level recommended to take action to reduce the concentrations of radon in indoor air. The unattached-radon average concentrations were also lower than the value recommended by the European Union for new houses. As the unattached-radon concentrations were below the international level recommended to take action to reduce the radon concentration in air, it was concluded that during the period of sampling, there was low risk to human health due to the inhalation of unattached radon in these four buildings. 相似文献
14.
A trace elements study of various samples from the Keana brines field, middle Benue Trough was carried-out to determine the
extent to which Pb–Zn–S and BaSO4 mineralisations have affected the quality of the brines and the waters in the area. Different sample media such as well-water,
pond water, brine spring pool water, stream water, stream sediments etc. were analysed. Geochemical results show that Cu,
Zn, Pb, As and S are concentrated in the waters (0.3, 0.36, 0.05, 0.07 and 1 1.5 ppm respectively). These elements are more
concentrated in both the spring and pond waters, suggesting that the spring water could have acted as the transport medium
for these elements released from deep-seated sources. Transitions elements (Ti, V, Cr, Fe, Co, Ni and Sr) are concentrated
in the waters. Compared to the World Health Organization (WHO) admissible limits, the well waters present very high concentrations
in Cd (0.56 ppm) and Sb (0.40 ppm) (200× and 70× WHO admissible values respectively). There is a preferential concentration
of transition elements (Ti, V, Fe, Co and Ni) in the sediments (41.38, 362, 52.21, 269 and 54 ppm respectively) than in the
waters (0.70, 0.05, 5.6, 0.04 and 0.02 ppm respectively). Similarly, Cu, Zn, Pb and As are concentrated in the sediments (44,
72, 41 and 14 ppm respectively). The concentrations of transition elements (Ti, V, Cr, Fe, Co and Ni) in the refined salt
were highly elevated (784, 363, 283, 105, 59.2 and 42.6 ppm respectively) (7000–10,000× well water). Similarly, the concentrations
of As, Pb, Br and Sr in the refined salt were also alarming (11.6, 16.4, 16.4 and 122 ppm respectively), (1000, 700, 3000
and 20,000× well water values respectively). S on the other hand is absent. One of the striking features is the absence of
I, Cd, Sb and Se in the refined salt crystals which were detected in the waters and the brines. Compared to WHO admissible
values, the refined salt crystal concentrations for Ni (426 ppm) and Cr (283 ppm) were also very high (2000× WHO values respectively)
and to a lesser extent Cu (26.9 ppm) and Zn (21.7 ppm) (12 and 7× WHO values respectively). 相似文献
15.
Germund Tyler 《Chemistry and Ecology》2000,17(2):103-112
Uptake of arsenic, molybdenum, uranium and vanadium by species of natural vegetation (Agrostis capillaris, Betula pendula, Calluna vulgaris, and Deschampsia flexuosa) on two contrasting, highly acid soils (pH of soil solution 4.2-4.3), differing in natural abundance of these elements, was compared. the soil developed from alum shale was rich in these elements, the soil from a gneiss moraine was poor in these elements. Leaf/ above ground biomass concentrations were positively related to soil concentrations of the elements, but least closely for uranium, and vanadium tended to be excluded by the plants, compared to arsenic, and especially to molybdenum. the relationships between soil and plant concentrations were broadly similar whether nitric acid-digestible or the much lower DTPA extractable soil fractions were considered. Leaf concentrations of plants from the shale and the gneiss soil, respectively, ranged 1.41-2.76 and 0.30-0.58 nmolg-1 dry weight for arsenic, 14-140 and 0.5-9.6 for molybdenum, 0.031-0.069 and 0.013-0.030 for uranium, 2.3-6.4 and 0.75-3.3 for vanadium. 相似文献
16.
The effects of agricultural improvement by cultivation, re-seeding, lime and fertiliser additions on the soil solution chemistry of acid podzolic soils have been investigated in a field experiment in a mid-Wales catchment. the treatment resulted in an increase in the pH, alkalinity and calcium content of soil waters from the surface, organic-rich horizon. in the year following treatment, soil waters in the mineral horizons became more acid and had higher aluminium concentrations than observed at the control site. This response is ascribed to soil water acidification resulting from increased nitrification rates following liming and cultivation. in subsequent years, soil water acidity in these lower horizons was neutralised by lime-rich water percolating from the surface. No changes in stream water acidity and calcium content were observed in the catchment containing the area of agriculturally improved soils. This suggests that the selective treatment of moorland catchments to improve agricultural productivity may not always be accompanied by amelioration of acid stream water. 相似文献
17.
Urban geochemistry: A study of element distributions in the soils of tallinn (Estonia) 总被引:17,自引:0,他引:17
First results are presented from the Urban geochemistry of Tallinn, a project supported by the Scientific and Environmental Affairs Division of NATO. The distribution of chemical elements in 532 samples of the topsoils from the territory of the biggest industrial centre of Estonia (pop. 500,000) is interpreted. Statistical analysis and mapping of major and trace elements at the territory of the Tallinn region and of the city were performed and background values and local anomalies of chemical elements on the territory were determined. The investigation focussed on the determination of zones with anomalously high concentrations of elements and the relationships of soil contamination with different pollution sources. The increase of the element concentrations has natural as well as anthropogenic origins. A detailed comparative analysis of the element distributions and the results of a factor analysis showed that the distribution of the major chemical elements depended mainly on the composition of the underlying sedimentary rocks.The territory of Tallinn is characterised by relatively high and widespread concentrations of Ba, Cr, Ga, Ni, Ti and Zn. Especially intensive local concentrations were determined for As, Cr, Mn, Ni, Pb, S, V and Zn, which are typical for the local pollution of the soils by industrial sources. The levels of As, Cr, Mn and V are more than three times. Pb and Zn are more than five times higher in the geochemical anomalies than for background levels. For the Tallinn region two major associations of elements connected with industrial pollutions of the soil are typical: the first association includes Ba, Cr, Mn, Ni and partly Fe and the second one includes As, Pb and Zn. For the city of Tallinn an increase of Ag, Ba, Be, La, Pb, Sn and Zn concentration in the soil was detected. Ba, Cr, Mn and Ni occur in high concentrations in the soils around Maardu. Different types of contamination sources can be identified in Tallinn and its suburbs. 相似文献
18.
Marcos?R.?Moreira-Silva Carlos?A.?Tello?Sáenz Jo?o?O.?Rodrigues?Nunes Manoel?Godoy Marcos?F.?S.?Teixeira
The emission of radon gas in regions of geological faults, during the radioactive decay of uranium and thorium, results in the formation of lead isotopes 210Pb, 208Pb, 207Pb and 206Pb. As a consequence, the lead contamination in the soil poses a hazard to humans through ingestion of food, contaminated water, and even by direct contact with the soil contaminant. So far the relationship between the occurrence of geological faults and soil Pb contamination has not been established. Here, we studied lead in soils of regions with geological faults and their possible relationship with radon emissions. Soils were sampled from Presidente Prudente located in the far west of São Paulo State, Brazil. The region has strong evidence of the existence and direction of geological faults at depths of approximately 200 m. Soil sampling was done according to the USEPA 3050 method. Total lead was quantified by anodic stripping voltammetry. Results show that the total Pb concentration increases systematically with soil depth. This finding is explained by the fact that the lead originates from radon emissions. Pearson correlation analysis further proves a relationship of the nuclear track density obtained with CR-39 detectors, and mean Pb levels within each soil profile. Overall, our findings should improve risk evaluation of Pb contamination derived from radon emission and geological faults. 相似文献
19.
The influence of naturally occurring uraniferous black shales on cadmium, molybdenum and selenium concentrations in soils
and plants is examined. The possible implications of element concentrations to animal and human health are considered for
the Deog-Pyoung area.
Geochemical surveys have been undertaken within 13 river tributary valleys in the area underlain by uraniferous black shales
and black slates or grey chlorite schists. Sampling of rocks, soils and plants has been carried out along transect lines within
each valley. Samples were analysed for trace elements by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
and for uranium by Neutron Activation Analysis (NAA). Soil pH, cation exchange capacity, loss on ignition and particle size
distribution have been measured for selected samples.
Average trace element concentrations of the Okchon uraniferous black shales were 6.3 μg g−1 Cd, 136 μg g−1 Mo and 8.6 μg g−1 Se. Soils derived from these rocks tend to reflect their extreme geochemical composition. Trace element concentrations in
alluvial soils derived in part from these black shales averaged 1.2 μg g−1 Cd, 20 μg g−1 Mo and 1.5 μg g−1 Se. Trace element concentrations in plants were found to be influenced by those of soils. Cadmium accumulated in tobacco
leaves up to 46 μg g−1 (D.M.) and leafy plants such as lettuce contain up to 0.5 μg g−1 Se (D.M.).
In addition to total concentrations in soils, soil pH is a major factor influencing uptake of Mo into crop plants and soil
texture for Se. Concentrations of trace elements in plants also varied between plant species. The relative concentrations
of Cd were found to vary in the order tobacco > lettuce > red pepper > rice grain.
Elevated concentrations of Cd in crop plants and in tobacco may possibly have deleterious effects on human health in this
area. The low Cu:Mo ratio in rice stalk of 2.65:1 may be associated with disturbed Cu metabolism in ruminant animals which
regularly consume this material. 相似文献
20.
The area around Chandidongri (latitude 21 deg 02 prime N and longitude 80 deg 37 prime E) is covered by granitic gneisses and amphibolites of the Amgaon Group and granites and rhyolites of the Dongargarh super group. The granites which cover the major portion of the area have been intruded into by a number of dolerite and epidiorite dykes and traversed by a few N–S trending shear zones. A well-known fluorite deposit is located along the Lamtidongri–Kotnapani shear zone. Besides this deposit, the authors have located a few occurrences of fluorite along other shear zones where epidiorite dykes are in association with granites. A number of cases of fluorosis have been reported from those parts of Rajasthan and Andhra Pradesh which are covered by granitic rocks and also from the eastern parts of Bhandara district which are adjacent to the area described here. The Chandidongri area is mainly covered by granitic rocks, which at places show the presence of fluorite mineralisation. Taking into consideration these facts, the authors have investigated the area to study the cases of fluorosis if any, and the impact of geology and fluorite mining on the water quality in this region. During the survey, we have not come across any cases of fluorosis in this region. The pH is more than 7 and the fluoride concentration is within the permissible limit. 相似文献