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331.
Fish were kept in non-toxic water or at 0.5, 0.25 and 0.125 of the LC50,96h of the ten-side or insecticide for 24 h and fed with toxified and non-toxified feed. Toxified feed in normal water resulted in a maximum feed intake, while normal feed in toxified water resulted in a minimum one. In each case, the feed intake was lower compared with the control, and the feed intake was inversely proportional to the toxicant concentration. In a simple respirometer the oxygen consumption in mg · kg?1 · h?1 was tested for 1, 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, 72, 84 and 96 h of exposure to 1.5, 1.0 and 0.5 of the LC50,96h of both substances. It was a flow device which was closed only for measurement for one hour. 1.5 LC50 Aldrin causes a continuous reduction of respiration until death. The same effect occurred with Cl. batrachus for 1.5 LC50 of the tenside, whereas with C. mrigala death was caused by a pronounced increase of respiration. In all other cases, after a phase of sensitization for 4 … 8 h respiration increased considerably to more than 300% of the control, which was followed after 12 … 24 h by acclimatization to normal respiration values. 相似文献
332.
The present investigation is designed to work out the isolated and in-combination effects of Zn2+, Cr6+ and Ni2+ to a fish Mystus vittatus. From all the 12 combinations, 6 are antagonistic and 6 are synergistic. The combination Cr/Ni is highly synergistic while combination (Cr + Ni)/Zn is highly antagonistic in nature. The possible mechanisms responsible for antagonistic and synergistic combinations have been discussed and indicated as the occupation of critical receptor sites by less toxic metal (antagonism) or intrinsic affinity of the individual metal for the critical site or relative concentration and distribution of the metals within the target organ site (synergism). The results drawn can be indicated in terms of the effective concentration required to reach a particular level for a particular biological end point and can be expressed as follows. 相似文献
333.
Geochemistry of Cenezoic volcanic rocks, Baja California, Mexico: Implications for the petrogenesis of post-subduction magmas 总被引:2,自引:0,他引:2
A.D. Saunders G. Rogers G.F. Marriner D.J. Terrell S.P. Verma 《Journal of Volcanology and Geothermal Research》1987,32(1-3)
Late Cenozoic volcanism in Baja California records the effects of cessation of subduction at a previously convergent, plate margin. Prior to 12.5 m.y., when subduction along the margin of Baja ceased, the predominant volcanic activity had a calc-alkaline signature, ranging in composition from basalt to rhyolite. Acidic pyroclastic activity was common, and possibly represented the westermost, distal edge of the Sierra Madre Occidental province. After 12.5 m.y., however, the style and composition of the magmatic products changed dramatically. The dominant rock type within the Jaraguay and San Borja volcanic fields is a magnesian andesite, with up to 8% MgO at 57% SiO2, low Fe/Mg ratios, and high Na/K ratios. These rocks have unusual trace-element characteristics, with high abundances of Sr (up to 3000 ppm), low contents of Rb; K/Rb ratios are very high (usually over 1000, and up to 2500), and Rb/Sr ratios are low (less than 0.01). Furthermore, Lan/Ybn ratios are high, consistent with derivation from a mantle source with fractionated REE patterns. 87Sr/86Sr ratios are less than 0.7048, and usually less than 0.7040, whereas the pre-12.5 m.y. lavas have 87Sr/86Sr ratios between 0.7038 and 0.7063. We have previously termed these rocks bajaites, in order to distinguish them from other magnesian andesites. Bajaites also occur in southernmost Chile and the Aleutian Islands, areas which also have histories of attempted or successful ridge subduction.It is proposed that the bajaite series is produced during the unusual physico-chemical conditions operating during the subduction of young oceanic lithosphere, or subduction of a spreading centre. During normal subduction, the oceanic crust dehydrates, releasing volatiles (water, Rb and other large-ion lithophile elements) into the overlying wedge. Subduction of younger crust will result in a progressive decrease, and eventual cessation of the transfer of volatiles when subduction stops. Thermal rebound of the mantle may cause the slab to melt, perhaps under eclogitestable conditions. The resulting melt will be heavy-REE-depleted, perhaps dacitic, but will otherwise inherit MORB-like Rb/Sr and K/Rb ratios. The ascending melt will react with the mantle to form the source of the bajaitic rocks. Furthermore, any amphibole in the mantle, stabilised during the higher PH2O conditions of earlier subduction, will break down and contribute a high-K/Rb ratio component.The implications of this study are that firstly, the subducted slab does not contribute a highly fractionated REE component in most modern arcs (i.e. the slab does not melt); secondly, Rb has a very short residence time in the mantle, and its abundance in arc rocks is a direct reflection of the input from the dehydrating slab; and thirdly, bajaitelike rocks may provide recognition of attempted or successful ridge subduction in the geologic past. 相似文献
334.
– Five aquatic ecosystems, Yamuna river, Krishna river Eastern Kalinadi, Kadrabad drain and Peacock lake have been studied with reference to diversity and physico-chemical characteristics and biological indices. – A list of species have been selected with reference to polluted, mildly polluted or unpolluted water conditions. Though it is difficult to call any species strictly indicator species, certain species of Bacillariophyceae, bottom biota and Entomostraca can be regarded as indicative species. – The quantitative distributions of the species of different groups have been analysed statistically. Margalef's Community Diversity Index (d), Shannon Weaver Function, coefficient of rank correlation and partial and multiple correlation coefficient were calculated as to find out the order of precedence in different taxonomical groups. – The linear regression against BOD and the whole biocenosis were calculated, which indicate the relation as diversity d=6.7854 –0.0080 BOD±0.9695 where r2= B=0.7365. Similarly, multiple linear regressions were also calculated using diversity against BOD, pH and temperature for each aquatic ecosystem. – All these observations indicate that diversity of organisms can be used to measure the water pollution intensity. 相似文献
335.
Pradeep K. Aggarwal Fred J. Longstaffe 《Contributions to Mineralogy and Petrology》1987,96(3):314-325
Oxygen-isotope compositions have been measured for whole-rock and mineral samples of host and hydrothermally altered rocks from three massive sulfide deposits, Centennial (CL), Spruce Point (SP), and Anderson Lake (AL), in the Flin Flon — Snow Lake belt, Manitoba. Wholerock
18O values of felsic metavolcanic, host rocks (+8.5 to +16.1) are higher than those of altered rocks from the three deposits. The
18O values of altered rocks are lower in the chlorite zone and muscovite zone-I (CL=+ 5.3; SP=+5.4 to +8.3; AL= +3.7 to +5.9) than in the gradational zone (CL= +9.9 to +11.7; SP= +8.4 to +9.8; AL= + 6.6 to +7.7). Muscovite schist (Muscovite Zone-II) enveloping the Anderson Lake ore body has
18O values of +7.2 to +8.3. Quartz, biotite, muscovite, and chlorite separated from the altered rocks have lower
18O values compared to the same minerals separated from the host rocks. However, isotopic fractionation between mineral-pairs is generally similar in both host and altered rocks.It is interpreted that differences in the oxygen-isotope compositions of the altered and host rocks were produced prior to metamorphism, during hydrothermal alteration related to ore-deposition. Isotopic homogenization during metamorphism occurred on a grain-to-grain scale, over no more than a few meters. The whole-rock
18O values did not change significantly during metamorphism. The generally lower
18O values of altered rocks, the Cu-rich nature of the ore and the occurrence of the muscovite zone-II at Anderson Lake are consistent with the presence of higher temperature hydrothermal fluids at Anderson Lake than at the Centennial and Spruce Point deposits. 相似文献
336.
The study of reservoir-induced seismicity offers a controlled setting to understand the physics of the earthquake process. Data from detailed investigations at reservoirs in South Carolina suggested that the mechanism of transmission of stress to hypocentral locations is by a process of diffusion of pore pressure (Pp). These results were compared with available worldwide data. The seismic hydraulic diffusivity,
s
, was estimated from various seismological observations, and was found to be a good estimate of the material hydraulic diffusivity, . Application of these results to a dedicated experiment to understand RIS at Monticello Reservoir, S.C., suggested that the diffusing Pp front plays a dual role in the triggering of seismicity. The spatial and temporal pattern of RIS can be explained by the mechanical effect of diffusion of Pp with a characteristic hydraulic diffusivity within an order of magnitude of 5×104 cm2/s, corresponding to permeability values in the millidarcy range. The triggering of seismicity is due to the combined mechanical effect of Pp in reducing the strength and, possibly, the chemical effect in reducing the coefficient of friction between the clays in the pre-existing fractures and the rocks that enclose these fractures. 相似文献
337.
The Eastern Ghats are a prominent topographic feature on the Indian Peninsula, stretching from the southern tip of the peninsula to near Bhubaneswar (20°N, 86°E) along the east coast. The belt is characterised by occurrences of high grade metamorphic rocks such as pyroxene granulites, sillimanite gneisses, charnockites and gabbro-anorthosite masses. The gravity field over the Eastern Ghats is appreciably positive as compared to the surrounding low grade gneissic terrain.Analysis of the gravity field along the coastal and southern granulite terrain comprising the Eastern Ghats shows that a large number of gravity highs are associated with charnockites of basic and intermediate nature as well as gabbro-anorthosite masses. The lows appear to be associated with acid charnockites, syenite masses or granitic intrusives.The boundary between the Eastern Ghats terrain and the adjoining Dharwar/Bastar cratons appears to be a faulted one. The crust underneath the Eastern Ghats is inferred to be of a higher density than that of the Dharwar/Bastar cratons to its west. The gravity field over the Eastern Ghats is compared to that of similar terrains in other parts of the world. It is inferred that the Eastern Ghats are characterised by a crust of higher than normal density. 相似文献
338.
About seven hundred gravity stations were established 2–3 miles apart over the Precambrian terrain of Singhbhum that lies between latitude 22° 15′ to 23°°15′N and longitude 85° to 87°E. Bouguer anomalies ranging from +4 to −62 mGal are found in the area. The observed Bouguer anomaly map was analyzed into regional and residual components. The residual anomaly map shows an excellent correlation with geology. The Singhbhum granite batholith is associated with several gravity lows. The residual anomaly map outlines nine plutonic granitic masses within the Singhbhum batholith. Negative residuals are also observed over some intrusive granites outside the batholith. Residual gravity highs are noted over the Dalma hill as well as over the Dhanjori lava complex on the eastern part of the Singhbhum batholith.Two-dimensional models suggestive of subsurface configuration of several major geologic units in the area are presented. These indicate that some of the plutonic granites within the Singhbhum batholith are of relatively large dimensions. The basin containing the Iron Ore Group of rocks to the west of the batholith, as well as the basin containing Singhbhum Group of rocks outside the Copper Belt thrust, may have sedimentary thicknesses of the order of 6–7 km. The Dalma lavas attain their maximum thickness of about 2.5 km in the form of a syncline, underneath which the Singhbhum Group of rocks is also found to be the thickest. The Copper Belt thrust, a major Precambrian fracture around the Singhbhum batholith, is moderately north-dipping near the surface but possibly attains a steeper slope at depth. The thrust appears to be quite deep seated. A threedimensional computer-based model for the Dhanjori lava—gabbro complex on the eastern part of the Singhbhum batholith has been deduced. Maximum thickness of these basic rocks is found to exist underneath a thin cap of granophyre. The geological implication of these results is discussed.Variation in the regional anomalies seems to be attributable to a mass deficiency under the Singhbhum batholith. The batholith may extend subsurfacially towards the north across the Copper Belt thrust. The northern tip of the batholith probably became dissected along the line of intersection of the two orogenic trends in the area and subsided. Over this subsided part, the Singhbhum Group of rocks was deposited at a later stage. Gravity data suggest a fairly large amount of subsidence in the area. 相似文献
339.
Stream pollution by industrial wastes is posing a problem in Uttar Pradesh. In the present investigations an attempt has been made to study the ecological features of a section of the Kalinadi so as to find out the cumulative or detrimental effect of pollution on fish and fisheries by the effluent discharge of sugar factory and distillery wastes near Mansurpur (District Muzaffarnagar), U. P. This paper is part I of the project. The liquid wastes produced by the sugar factory vary from 66 × 106 to 88 × 106 litres/day excluding condenser water and contain variable quantities of cane fibres, cellulose, lime, waxes, fermented sugar juice, mollasses, and some quantities of sulphate, phosphate, and nitrogen, the oxygen being nil with high values of B. O. D. and C. O. D. The liquid waste from the distillery is called spent wash. The spent wash (62 × 104 litres/day) is highly coloured and acidic (pH 4.3 … 2.9). The B. O. D. and C. O. D. values were very high in the order of 28,526 mg/1 … 45,146 mg/1 and 52,516 mg/1 to 66,862 mg/1. Thus total waste of about 17.3 × 106 litres with no oxygen and high B. O. D. (9,600 mg/1 … 10,116 mg/1) is let off into the Kalinadi. Hydrometric observations on the Kalinadi show that the pollutional hazard is appreciable during the low flow period of the river. The wastes affect the river in a number of ways:
- - The deposition of cellulose fibres, organic and inorganic matter affects the substratum adversely. The blackish brown colour of the wastes affects the light penetration by limiting the growth of phytoplankton.
- - There appears to be no potential danger to the river from the electrolyte pollution as the specific conductivity lies below limiting values.
- - Changes in pH in river water due to the acidic nature of the wastes do not affect directly the fauna and flora, but the acidic condition becomes lethal in the presence of low oxygen and high temperature values.
- - The high load of organic matter present in the wastes draws heavily on the oxygen budget of the river and adversely changes the water and bottom quality of the river for a stretch of 10 km, which adversely affects the environmental condition of both fish and fish food.
- - The presence of sulphuric acid in distillery waste and hydrogen sulphide in river water is toxic to fish and fish food.
- - The decomposition of organic matter in an anaerobic condition and in another favourable environment, as with a low redox potential, the presence of sufficient organic matter and a constant supply of sulphur-reducing bacteria, produces more hydrogen sulphide which may be detrimental or sublethal in the presence of a low oxygen saturation and high temperature.
- - The oxygen level increases at each succeeding station through reaeration and dilution with the lowering of B. O. D. and C. O. D. The oxygen-sag curve is like a typical spoon with handle-shape.
340.
From the biological data presented here it is difficult to define any species of fish as an indicator of pollution in the strict sense. Nevertheless, the following generalizations are possible.
- - Species as Wallago attu, Clarias batrachus, Heteropneustes fossilis, Ophiocephalus striatus and Oph. punctatus occur in good number in the polluted stretch and seem to be tolerant species.
- - The species as Esomus danrica, Labeo rohita, Labeo gonius, L. bata, Catla catla, Cirrhina mrigala, Barbus chagunio, Barbus spec., Notopterus notopterus and Mugil corsula are most sensitive and disappear first in the polluted stretch.
- - The species as Barilius bola, B. bendelisis, Nemacheilus latius, Notopterus chitala, Collichrous bimaculatus, and Nandus nandus are moderately sensitive.
- - It appears that the main damage is caused to carp and feather-back fishes. The whole stretch of heavy pollution is almost devoid of carp and featherback.
- - The higher number of protozoans, chironomids, maggots and the decrease in the number of mollusca can be considered as the indicator of pollution, because of their abundance in polluted zones.
- - Chlorella, Lyngbya, Gyrosigma and Euglena (algae), Viviparius (mollusc) and Bosmina (crustacea) are very sensitive to pollution.
- - Oscillatoria, Pandorina, Anabaena, Nitzschia, Closterium (algae), Branchionus, Rotatoria (rotifers) and Naidium (annelid) are moderately sensitive.
- - Synedra, Spirogyra, Desmidium, Rivularia, Navicula, Fragillaria Phacus, Arcella and Vorticella are fairly tolerant forms.
- The stretch studied has been subdivided into five zones with characteristic features:
- - The Oligosaprobic Zone - characterized by a sufficient oxygen saturation, low B. O. D. and C. O. D., with a good fauna and flora.
- - The Polysaprobic Zone - with low oxygen saturation, high B. O. D. and C. O. D. and hydrogen sulphides with a restricted fauna and flora.
- - The α-Mesosaprobic zone - with moderate oxygen saturation, moderate B. O. D. and C. O. D. traces of hydrogen sulphide with the improvement of the fauna and flora.
- - The β-Mesosaprobic Zone - with fair oxygen saturation, low B. O. D. and C. O. D., with the reappearence of fauna and flora.
- - The Oligosaprobic Zone - similar to the zone of low pollution in all characteristics.