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1.
To test the relative effectiveness of stream water and sediment as geochemical exploration media in the Rio Tanama porphyry copper district of Puerto Rico, we collected and subsequently analyzed samples of water and sediment from 29 sites in the rivers and tributaries of the district. Copper, Mo, Pb, Zn, SO42?, and pH were determined in the waters; Cu, Mo, Pb, and Zn were determined in the sediments. In addition, copper in five partial extractions from the sediments was determined. Geochemical contrast (anomaly-to-background quotient) was the principal criterion by which the effectiveness of the two media and the five extractions were judged.Among the distribution patterns of metals in stream water, that of copper most clearly delineates the known porphyry copper deposits and yields the longest discernable dispersion train. The distribution patterns of Mo, Pb, and Zn in water show little relationship to the known mineralization. The distribution of SO42? in water delineates the copper deposits and also the more extensive pyrite alteration in the district; its recognizable downstream dispersion train is substantially longer than those of the metals, either in water or sediment. Low pH values in small tributaries delineate areas of known sulfide mineralization.The distribution patterns of copper in sediments clearly delineate the known deposits, and the dispersion trains are longer than those of copper in water.The partial determinations of copper related to secondary iron and manganese oxides yield the strongest geochemical contrasts and longest recognizable dispersion trains. Significantly high concentrations of molybdenum in sediments were found at only three sites, all within one-half km downstream of the known copper deposits. The distribution patterns of lead and zinc in sediments are clearly related to the known primary lead-zinc haloes around the copper deposits. The recognizable downstream dispersion trains of lead and zinc are shorter than those of copper.  相似文献   

2.
Biological technologies for wastewater remediation techniques employed to remove contaminants in urban stream water are increasingly receiving attention worldwide. The purpose of this study was therefore to determine the concentrations of lead, cadmium, copper, zinc, manganese and iron in algal biomass and establish the feasibility of using algae in phytoextraction and bio-monitoring of environmental quality. Analysis of algal biomass samples in the Nakivubo urban stream ecosystem, Kampala, Uganda, showed that there was contamination by lead, cadmium, copper and zinc as indicated by enrichment factor and pollution load index values. It is suspected that industrial and vehicular emissions are the major sources of these pollutants. Calculated bio-concentration factor was >- 1000 but with low concentration thresholds in each element, suggesting that algal biomass was a very good heavy metal accumulator. The bio-concentration values in algal biomass were found to be in the order of copper > zinc > lead > cadmium in the Nakivubo Channelized stream. In conclusion, algae can be a promising aquatic bio-filter plant for phytoextraction and bio-monitoring of polluted urban stream ecosystems and wastewater.  相似文献   

3.
Globally, aquatic ecosystems are highly polluted with heavy metals arising from anthropogenic and terrigenous sources. The objective of this study was to investigate the pollution of stream sediments and possible sources of pollutants in Nakivubo Channel Kampala, Uganda. Stream sediments were collected and analysed for heavy metal concentration using flame atomic absorption spectrophotometer. The degree of pollution in Nakivubo channelized stream sediments for lead, cadmium, copper, zinc, manganese and iron was assessed using enrichment factor, geo-accumulation index and pollution load index. The results indicated that (1) the sediments have been polluted with lead, cadmium and zinc and have high anthropogenic influences; (2) the calculation of geo-accumulation index suggest that Nakivubo stream sediments have background concentration for copper, manganese and Fe (I geo ≤ 0); (3) factor analysis results reveal three sources of pollutants as explained by three factors (75.0 %); (i) mixed origin or retention phenomena of industrial and vehicular emissions; (ii) terrigenous and (iii) dual origin of zinc (vehicular and industrial). In conclusion, the co-precipitation (inclusion, occlusion and adsorption) of lead, cadmium and zinc with manganese and iron hydroxides, scavenging ability of other metals, very low dissolved oxygen and slightly acidic to slightly alkaline pH in stream water could account for the active accumulation of heavy metals in Nakivubo stream sediments. These phenomena may pose a risk of secondary water pollution under sediment disturbance and/or changes in the geo-chemistry of sediments.  相似文献   

4.
To improve comminution efficiency, the effects of several process parameters on the comminution capability of high pressure water jet mill were investigated. Fractal dimension of particle size distribution, as an index of water jet mill comminution capability, was used for describing the fineness of the comminution product. Nine process parameters including the pump pressure, the mixing tube length and diameter, the coal particle mass flow rate, the diameter of feed material particle, the standoff distance, loading times, hardness of the target and the impact angle were investigated individually. The results obtained from this study provide deeper insight into the high pressure water jet comminution technology and a basis for process parameters optimization. We also show that the fractal dimension of particle size distribution can be used to monitor the comminution capability and estimate the degree of particle comminution.  相似文献   

5.
In the present study sediment and water samples collected from Kowsar Dam reservoir in Kohkiluye and Boyerahmad Province, southwest of Iran, are subjected to bulk digestion and chemical partitioning. The concentrations of nickel, lead, zinc, copper, cobalt, cadmium, manganese and iron in water and bed sediment were determined by atomic absorption spectrometry. The concentrations of metals bounded to five sedimentary phases were estimated. On this basis, the proportions of natural and anthropogenic elements were calculated.The anthropogenic portion of elements are as follows: zinc (96 %)> cobalt (88 %)> iron (78 %)> magnesium (78 %)> nickel (78 %)> copper (66 %)> lead (63 %)> cadmium (59 %). The results show sediment contamination by nickel, cadmium and lead, according to the world aquatic sediments and mean earth crust values. Manganese and copper have strong association with organic matter and are of high portion of sulfide bounded ions. Finally, The degree of sediment contamination was evaluated using enrichment factor, geo-accumulation index (Igeo) and pollution index (IPoll). The sediments were identified to be of high cadmium and lead pollution index. The pattern of pollution intensity according to enrichment factor is as follows; manganese (1.25) < copper (1.63) < zinc (1.93) < cobalt (2.35) < nickel (3.83) < lead (12.63) < cadmium (78.32). Cluster analysis was performed in order to assess heavy metal interactions between water and sediment. Accordingly, nickel, cadmium and copper are earth originated. Zinc, copper and manganese are dominated by pH. All the elemental concentrations in water and sediment are correlated except for sedimental copper.  相似文献   

6.
The remobilization of iron, manganese, cobalt, cadmium, copper and zinc in the pore water of estuarine sediment cores at Yingkou was assessed using diffusive equilibrium in thin films and diffusive gradients in thin films techniques. A relatively anoxic system (+33.7 to ?224.1 mV) in the sediment cores might cause the reductive release of iron, manganese and cobalt into pore water from the estuarine sediment. High-average concentrations of iron (47.85 μg ml?1) and manganese (3.81 μg ml?1) were observed using diffusive equilibrium in thin films on the sediment core, but the concentration of cobalt (18.02 ng ml?1) was relatively low. A strong correlation between iron and cobalt was observed based on the vertical profiles of the metals. Manganese and iron were more readily released from the solid phase to the solution. The peak cobalt, copper and zinc concentrations were observed in the upper layer (2–4 cm) measured using diffusive gradients in thin films. However, the peak iron, manganese and cobalt concentrations were located in the deeper layer (≥7 cm). In addition, the concentration profiles measured using diffusive gradients in thin films of cobalt, copper and zinc were independent of the iron, manganese and cobalt distribution with respect to depth.  相似文献   

7.
Grinding mills are commonly used in the Florida phosphate industry to reduce particle size. The corrosion of metallic grinding media and mill liner is a very serious problem, particularly under acidic conditions as encountered in the Florida phosphate fertilizer industry. A statistical Box–Behnken Design (BBD) of experiments was performed to evaluate the effects of individual operating variables and their interactions on the wear rate of high chromium alloy during phosphate grinding. The variables examined in this study included grinding time, solution pH, rotation speed, mill crop load, and solids percentage. The wear tests were conducted using a specially designed grinding mill whose electrochemical potential can be controlled. The most significant variables and optimum conditions were identified from statistical analysis of the experimental results using response surface methodology (RSM). It has been shown that solution pH had the most significant effect on the wear rate. The optimum process parameters for minimum wear rate were solution pH at 8.7, rotation speed at 61 rpm, solid percentage at 65% and crop load at 58%.  相似文献   

8.
Removal of arsenite from aqueous solution was carried out using electro-coagulation method. The experiments were conducted using copper–copper and zinc–zinc electrodes. The optimized experimental parameters were 2.0 mg/L initial concentration, 16.0-min processing time, 6.0 pH, 3.0-V applied voltage and 30 °C temperature for zinc–zinc electrodes while these values for copper–copper electrodes were 2.0 mg/L initial concentration, 20.0-min processing time, 7.0 pH, 5.0-V applied voltage and 30 °C temperature. The results demonstrated that zinc–zinc and copper–copper electrodes removed arsenite up to 99.89 and 99.56 %, respectively. The treated water was clear, colorless and odorless without any secondary contamination. There was no change in water quality after the removal of arsenite. The reported method is capable to remove arsenite from water at 6–7 pH range, which is a pH range of natural water. Therefore, this method may be the choice of arsenite removal from natural ground water.  相似文献   

9.
The distribution of ammonium citrate-leachable lead, zinc and cadmium among size fractions in stream sediments is strongly influenced by the presence of hydrous Mn-Fe oxides in the form of coatings on sediment grains. Distribution curves showing leachable metals as a function of particle size are given for eight samples from streams in New York State. These show certain features in common; in particular two concentrations of metals, one in the finest fractions, and a second peak in the coarse sand and gravel fraction. The latter can be explained as a result of the increasing prevalence and thickness of oxide coatings with increasing particle size, with the oxides serving as collectors for the heavy metals. The distribution of Zn and Cd in most of the samples closely parallels that of Mn; the distribution of Pb is less regular and appears to be related to Fe in some samples and Mn in others. The concentration of metals in the coarse fractions due to oxide coatings, combined with the common occurrence of oxide deposition in streams of glaciated regions, raises the possibility of using coarse materials for geochemical surveys and environmental heavy-metal studies.  相似文献   

10.
. Surficial sediments sampled from accreting and eroding areas along the coast of Guyana were examined for concentrations of heavy metals; aluminum, copper, chromium, iron, nickel, lead, vanadium and zinc. Twenty-four samples were collected, 12 from each of the eroding and accreting areas. For granulometric composition determination, samples were separated into particle-size fractions using sieving and hydrometer procedures. The consideration of three grain-size fractions (4.0, 5.0, and greater than 5.0 phi), plus 24 bulk samples less than 4.0 phi in diameter, required analyzing a total of 96 samples for the presence of heavy metals. The analysis employed was aquaregia digestion, followed by inductively coupled plasma optical emission spectroscopy. The statistical techniques of discriminant analysis, analysis of variance, and correlation and regression were used to analyze all obtained data. Discriminant analysis revealed that metal concentrations were statistically unique to each area. From the analysis of variance, and correlation and regression, it was discovered that the grain size of the sediment had a pronounced effect on the spatial distribution of heavy metals. The accreting area, with finer sediments, accumulated higher concentrations of heavy metals.  相似文献   

11.
The author attempts to explain some of the problems of hydrochemical prospecting by study of the migration of certain metals in water. In general the metal content of natural waters is lower than might be expected from their solubilities in pure water. In deposits of Kazakhstan there is a strong influence on the concentration of these elements by the chemical composition and pH of the water. Lead and copper contents are strongly dependent on pH (decreasing with greater pH) and zinc less so. The pH limit of indistinct and discontinuous hydrochemical anomalies is about 7 for copper, 7.2 for lead, and 7.5 for zinc. The predominantly alkaline or neutral waters of raremetal deposits precludes usage of copper, lead, and zinc as indicators. Careful studies are therefore necessary to adequately evaluate anomalies. Data from diverse, unmineralized rocks indicates that limestones and carbon-enriched bottom deposits, and acid intrusives and their tuffs, are most active in lead sorption. The structure of rocks and microorganisms influence metal content in associated waters.—J. A. Redden.  相似文献   

12.
An integrated physicochemical and hydrogeochemical assessment was carried out at an automobile junk market in Obosi and in residential areas in Anambra State, south-eastern Nigeria to examine the concentration of heavy metals in the groundwater and determine the quality of the water for drinking and other domestic purposes. Forty groundwater samples were collected from boreholes and hand-dug wells (three samples from Obosi and the rest from Onitsha). They were subjected to atomic absorption spectrometry using standard field and laboratory techniques and analysed for physicochemical and hydrogeochemical parameters. Results show that the groundwater in the study area is slightly acidic to neutral, soft to moderately hard when compared with the World Health Organization maximum allowable concentration values and the Nigerian Standards for Drinking Water Quality. The electrical conductivity, dissolved oxygen and biochemical oxygen demand ranged from 58 to 1796 μS/cm, 6.78 to 8.76 and 0.17 to 1.50 mg/L, respectively. Heavy metal concentrations measured (in ppm) in the water included nickel, manganese, copper and zinc and varied from 0 to 1.82, 0 to 0.195, 0 to 0.325 and 0 to 0.09, respectively, while heavy metal concentrations in the soil measured (in ppm) included iron, lead and cadmium and varied from 0 to 3.87, 0 to 1.80 and 0 to 7.38 mg/kg, respectively. Statistical results gave significant correlation (at 0.05) between electrical conductivity and total hardness, biochemical oxygen demand and dissolved oxygen, and several others elements. The study helps in the understanding of the chemistry of groundwater for long-term monitoring and management for the local community.  相似文献   

13.
Lake sediment composition as an indicator of mineralization within the catchment area has found widespread application in recent years, particularly in Canada. Results have indicated, however, the existence of varying relationships between lake sediment composition and mineralization resulting from local features of the limnological environment. Accordingly it was considered appropriate to examine the nature of metal transport in the lake and stream environment, the partitioning of metal between the stream waters and stream sediments and between lake waters and lake sediments to obtain some understanding of the factors that affect the lake sediment-mineralization relationship. This investigation was carried out over an area containing Pb-Zn occurrences of supposed “Mississippi-Valley type” in Grenville and Paleozoic bedrock in southeastern Ontario.The headwater drainage systems comprise active streams, swamps, beaver ponds and small lake-bog systems giving way downstream to open lakes. The beaver swamps and seasonal swamps act as drainage sinks for metals, restricting the extent of geochemical dispersion in drainage systems adjacent to mineralization. Selective extraction analysis of bog, stream and lake sediments indicates that metals are preferentially concentrated with amorphous iron oxides, which readily adsorb and complex lead and zinc and are stable in the alkaline environment common in swamps adjacent to carbonate-hosted lead-zinc mineralization. The accumulation of lead and zinc with amorphous iron oxides combined with the adsorbing and chelating action of organic matter on lead and zinc makes organic-rich sediments from these small swampy areas an excellent sample medium for reflecting local mineralization. Down drainage anomalies of these elements can be accentuated by selective analysis for the amorphous iron oxide-held metal, involving selective extraction techniques.In contrast, within larger lake systems, the analysis of water samples indicates that geochemical dispersion in surface waters in the high pH environment (pH = 8.0) associated with the carbonate-hosted lead-zinc deposits is extremely restricted. In this environment, anomalous metal contents in lake water were not evident in lakes adjacent to mineralization, while anomalous lake sediment compositions exist only in lakes immediately adjacent to Pb-Zn mineralization and do not extend down the drainage system. The restricted dispersion necessitates basing geochemical reconnaissance surveys on collection and analysis of samples from the headwater organic-rich swamps at a higher sample density and resulting higher cost than in areas where a lower sample density is acceptable due to a wider dispersion.  相似文献   

14.
The importance of trace metal scavenging by organic matter in geochemical samples was estimated using an alkaline sodium hypochlorite extraction to leach copper, zinc, molybdenum, iron and manganese from a variety of soils, and stream and lake sediments collected on the Nechako plateau, central British Columbia. The reagent oxidizes or dissolves most forms of organic matter, together with any sulphide minerals, to give strongly coloured extracts containing the associated trace elements at a pH where solution of other sample fractions is at a minimum. Metals precipitated due to alkaline conditions are redissolved by a succeeding distilled-water leach (pH 3.0 ± 0.3).A large fraction of the copper, zinc, molybdenum, and manganese held within the organic fraction of the A soil horizon is liberated whereas only minor amounts of copper, zinc, and manganese are released from inorganic soil (B and C) horizons. Molybdenum, however, is relatively soluble in all soils as the molybdate ion. Despite similar concentrations of organic matter in A horizon soils and stream sediments the latter release a lower proportion of their trace element content. Behaviour of the organic fraction of lake sediments varies from lake to lake and there is great variability in the association of copper, zinc, molybdenum and manganese with organic matter even within the same lake.The presence of organic matter in samples subjected to other partial extractions can be a deleterious factor if the organic fraction is not first removed by a hypochlorite extraction.  相似文献   

15.
富钴结壳超细标准物质的加工制备   总被引：3，自引：2，他引：1  
用气流磨制备了2个具有超细粒度的海山富钴结壳标准物质MCPt-1和MCPt-2。原样先经球磨成74μm(-200目),再用气流磨进行超细加工。样品粒度采用激光粒度仪检测,用粒度分布图和特征粒度来表达测量结果。两个样品的平均粒度分别为1.8μm和1.5μm(约2 000目),是目前粒度最小的标准物质。文章介绍了用于超细加工的流化床式气流磨原理与方法,展示了样品加工后的粒度分析结果,对比了国内外超细标准物质的概况。最后讨论了当前关注样品加工的重要性、超细加工的问题及超细样品分析研究的意义。  相似文献   

16.
In all geological scenarios, mineral water reactions will affect the water chemistry. As such, water resources in different rocks commonly involve different hydrogeological compartments. The aim of this work is to evaluate the influence of geology in the geochemistry signature of Itacolomi State Park waters. To do so, a survey of the geological units in the area was carried out, a geological/stratigraphic division was made, and its correlation with the main geological events was determined. Using the advantages of GIS, all the catchments were delimited. Based on this division, near 30 stream and lake segments were chosen for analyses. In each point, all physiochemical properties of the water were measured, and samples were collected to determine the concentrations of major and trace elements by ICP–OES. The dynamics of the Itacolomi State Park rock-soil and stream water solutions suggest that mixing of drainage waters from different bedrock and soil sources regulates stream water physical–chemical parameters and solute concentrations. The analytical data showed a clear correlation between the chemical compositions of the solute and the geological characteristics of the catchment. Units that are covered by iron oxide hardpan (Manso unit) and iron-banded formations (Custódio unit) show a large amount of soluble elements, including high values of Fe and Mn. On the other hand, the presence of high values of Al and K (Itacolomi unit) are a direct consequence of the presence of quartzite associated with low pH values.  相似文献   

17.
In the study, the relationship between some aquatic insect species (Ephemeroptera, Plecoptera, Trichoptera and Odonata) and some heavy metals (cadmium, lead, copper, zinc, nickel, iron and manganese) and boron were assessed using data obtained from the Ankara Stream, which flows through Ankara, the capital city of Turkey and receives high organic and industrial wastes. Sampling was carried out monthly along the Ankara Stream in 1991. environmental data were used to explain biological variation using multivariate techniques provided by the program canonical correspondence analysis ordination. The ordination method canonical correspondence analysis was applied to evaluate the relationships between environmental variables and distribution of aquatic insect larvae. Data sets were classified by two way indicator species analysis. In this study, aquatic insecta communities have been shown by canonical correspondence analysis ordination as related to total hardness, pH, cadmium, lead, copper, zinc, nickel, iron, manganese and boron. Cadmium, lead, copper and boron exceeded limits of the United States Environmental Protection Agency criteria for aquatic life. Trichopteran, Dinarthrum iranicum was an indicator of two way indicator species analysis and was placed close to the arrow representing copper. Odonate, Aeschna juncea was an indicator of two way indicator species analysis in site 10 and was placed close to the arrows representing manganese, lead, and nickel. Trichopteran, Cheumatopsyche lepida and odonate, Platycnemis pennipes were indicators of two way indicator species analysis for sites 6, 7, 11, 14, 15, 18 and were placed close to the arrows representing cadmium, boron, iron and total hardness.  相似文献   

18.
Red mud (RM), the solid waste of alumina industry, is high in silicon, calcium, aluminum and iron oxides. In this study, RM was activated by heat treatment at different temperatures and characterized with BET nitrogen gas sorption, scanning electron microscopy analysis and X-ray diffraction analysis. Immobilization of phosphorus, copper, zinc, and arsenic in swine manure by activated RM was studied as a function of RM dosage, pH and time. The immobilization efficiency of phosphorus, copper, zinc and arsenic increased with the increase in RM dosage, reaching 77, 39, 42, and 78 % when the proportion of RM to swine manure was 20 %. The pH of the solution had a significant impact on the immobilization and it was found that the efficiency increased with the increase in pH. During the 24-h immobilization, the efficiency increased with time and achieved equilibrium after 12 h. Chemical variations of phosphorus, copper, zinc, and arsenic during the immobilization process were investigated with sequential chemical extraction method and the results showed that the contents of non-labile fractions of phosphorus, heavy metals and arsenic increased obviously, whereas the contents of labile fractions decreased.  相似文献   

19.
Water quality monitoring in developing countries is inadequate, especially in stream water affected by urban effluents and runoff. The purpose of this study was to investigate heavy metal contaminants in the Nakivubo Stream water in Kampala, Uganda. Water samples Nakivubo Channelized Stream, tributaries and industrial effluents that drain into the stream were collected and analysed for the total elemental concentration using flame atomic absorption spectrophotometer. The results showed that: 1) the wastewater was highly enriched with lead and manganese above the maximum permissible limit; 2) the levels of dissolved oxygen were below the maximum permissible limit, while the biological oxygen demand was above the maximum permissible limit. All industrial effluents/wastewater were classified as strong (> 220 mg/L). Factor analysis results reveal two sources of pollutants; 1) mixed origin or chemical phenomena of industrial and vehicular emissions and 2) multiple origin of lead (vehicular, commercial establishment and industrial). In conclusion, Nakivubo Channelized Stream water is not enriched with heavy metals. These heavy metals (lead, cadmium and zinc) were rapidly removed by co-precipitation with manganese and iron hydroxides and total dissolved solids into stream sediments. This phenomena is controlled by pH in water.  相似文献   

20.
Stream sediments and aquatic bryophytes were used as exploration samples during a mineral reconnaissance survey of Chandalar Quadrangle, Alaska. Comparative data demonstrate that aquatic bryophytes accumulate copper, lead, zinc and mercury and locate massive sulfide mineralization better than stream sediments.Aquatic bryophytes are effective because of their ability to chemically bind dissolved trace elements, and physically trap micron-sized particulates. The former regulates mercury and manganese accumulation while the latter is more important for copper, lead, zinc and iron accumulation.Species effects seem to be negligible since statistical tests for measurable differences between bryophyte trace-element accumulations are not strongly positive. Therefore, the bryophyte data can be biogeochemically interpreted without rigorous species identification and statistical treatment.Overall, aquatic bryophytes are effective exploration samples in areas where they are abundant and stream sediments are not.  相似文献   

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