Lead （Pb） contamination has often been recorded in Chinese field soils. In recent years, efforts have been made to inves- tigate Pb toxicity thresholds in soils with plant growth and microbial assays. However, the i...Lead （Pb） contamination has often been recorded in Chinese field soils. In recent years, efforts have been made to inves- tigate Pb toxicity thresholds in soils with plant growth and microbial assays. However, the influence of soil properties on Pb toxicity impacts on soil microbial processes is poorly understood. In this study ten soils with different properties were collected in China to investigate the relationships between thresholds of Pb toxicity to soil microbes and soil properties. The effect of soil leaching on Pb toxicity was also investigated to determine the possible influence of added anions on Pb toxicity during dose-response tests. Toxicity was inferred by measuring substrate-induced nitrification in leached and non-leached soils after Pb addition. We found that soil microbe Pb toxicity thresholds （ECx, x=10, 50） differed significantly between the soils; the 10% inhibition ratio values （ECI0） ranged from 86 to 218 mg kg-1 in non-leached soils and from 101 to 313 mg kg in leached soils. The 50% inhibition ratio values （EC50） ranged from 403 to 969 mg kg^-1 in non-leached soils and from 494 to 1 603 mg kg^-1 in leached soils. Soil leaching increased EC50 and EC50 values by an average leaching factor （LF） of 1.46 and 1.33, respectively. Stepwise multiple regression models predicting Pb toxicity to soil microbes were developed based on ECx and soil properties. Based on these models, soil pH and organic carbon are the most important soil properties af- fecting Pb toxicity thresholds （R2〉0.60）. The quantitative relationship between Pb toxicity and soil properties will be helpful for developing soil-specific guidance on Pb toxicity thresholds in Chinese field soils.展开更多
The polymetallic(Pb,Zn,Cu,etc) ore belt on the southwestern margin of Tarim is one of the major regions with the greatest prospecting potential in Xinjiang.Reported in this paper are the lead isotope data for 66 sulfi...The polymetallic(Pb,Zn,Cu,etc) ore belt on the southwestern margin of Tarim is one of the major regions with the greatest prospecting potential in Xinjiang.Reported in this paper are the lead isotope data for 66 sulfide samples(including 50 galena samples,15 chalcopyrite samples and 1 pyrite sample) collected from such representative deposits as Tamu,Tiekelike,Kalangu,Abalieke,etc.in this ore belt.The Pb isotopic ratios of 206 Pb/204 Pb,207 Pb/204 Pb and 208 Pb/204 Pb in the galena samples range from 17.931 to 18.176,15.609 to 15.818 and 38.197 to 38.944,with the average values of 18.017,15.684 and 38.462,respectively.Those in the chalcopyrite samples range from 17.926 to 18.144,15.598 to 15.628 and 38.171 to 38.583,with the average values of 18.020,15.606 and 38.262,respectively.The pyrite sample has the Pb isotopic ratios of 206 Pb/204 Pb,207 Pb/204 Pb and 208 Pb/204 Pb to be 17.980,15.604 and 38.145,respectively.In combination with the previous Pb isotope data for sulfides,it is found that there is only a slight variation in the Pb isotopic composition of galena,chalcopyrite,sphalerite and pyrite in the ore belt.However,there is some difference in Pb isotopic characteristics between galena and chalcopyrite,especially the Pb isotopic composition of galena shows an obvious linear correlation with some other relevant parameters(e.g.β and γ).The comprehensive analysis suggested that lead in galena(maybe including sphalerite and pyrite) was derived principally from wall rocks and underlying basement,and that in chalcopyrite only originated from the basement.The single-stage model ages of these sulfides couldn't indicate the time limit of metallogenesis(Pb,Zn,Cu,etc.),and the positive linear correlations for the Pb isotopic composition of galena are of no single-stage and two-stage Pb-Pb isochron significance.Furthermore,there are significant differences in Pb isotopic composition characteristics between the genetic type of deposits in this polymetallic ore belt and the Mississippi Valley type(MVT).In addition,the authors also pointed out that there is a phenomenon of differentiation(not paragenesis) for lead and copper elements during the process of metallogenesis in this ore belt.展开更多
The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chi...The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic rcworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentary- metamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks arc introduced and compared with the orc-lead composition, so as to constrain the source of the ore lead. The result indicates that （1） sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their ^206pb/^204pb ratios arc within a range of 17.027- 17.317; ^207Pb/^204pb ratios, 15.451-15.786 and ^208Pb/^204pb ratios, 36.747-37.669; （2） the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks arc characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range, reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; （3） the sedimentary-metamorphic rocks in the mining district arc characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios arc obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic rcworking of these rocks; （4） Pb isotopic compositions of Late Proterozoic diorite-gabbro and Hercynian granite are higher than those of ores. Meanwhile, the Pb isotopic compositions of sulfides in the small-sized strata-penetrating mineralized veinlets formed at later stages arc completely consistent with that of sulfides in stratiform-banded ores, suggesting that these veiniets arc the product of autochthonous rcworking of the stratiform-banded ores during the period of metamorphism and the late magmatic superimposition-mineralization can be excluded; （5） amphibolite, whose protolith is basic volcanic rocks, has the same Pb isotopic compositions as ores, implying that ore lead was derived probably from basic volcanism. So, the source of ore-forming materials for the Huogeqi deposit is like that of the volcanic massive sulfide （VMS） deposits. However, the orebodies do not occur directly within the volcanic rocks, and instead they overlie the volcanic rocks, showing some differences from those typical VMS-type deposits.展开更多
In rice,high concentration of lead(Pb)can cause phyto-toxicity affecting several physiological functions.Cultivation of rice varieties that are resistant to Pb-induced oxidative stress is an important management strat...In rice,high concentration of lead(Pb)can cause phyto-toxicity affecting several physiological functions.Cultivation of rice varieties that are resistant to Pb-induced oxidative stress is an important management strategy in Pb-contaminated soils.In the current study,we evaluated four different rice cultivars for their response to Pb-induced stress.Three japonica type cultivars X-Jigna,Ediget,and Furat,and one Indica type cultivar Amber 33 were grown in soil containing different Pb concentrations(0 mM,0.6 mM,and 1.2 mM).The soil was treated with 0 mM or 0.6 mM or 1.2 mM Pb solution one month prior to rice seedling transplantation.Thereafter,four-week-old rice seedlings were transplanted into the treated soil and their responses were observed until maturity.The data revealed that a highest concentration of Pb(1.2 mM)induced significant reduction in agronomic traits such as plant height,number of tillers per plant,number of panicles per plant,and number of spikelets per panicle in all the rice cultivars.However,least reduction in the agronomic traits was observed in X-Jigna,whereas the highest reduction in the agronomic traits was observed in Ediget.Antioxidant activity of catalase(CAT),peroxidase(POD),polyphenol oxidase(PPO),and superoxide dismutase(SOD),was evaluated along with the accumulation of superoxide ions(O2.-),protein,proline,chlorophyll,sucrose,glucose,and fructose contents in all the rice cultivars.A significant increase in antioxidant activity and in the accumulation of proline and sucrose contents with the least reduction in the chlorophyll and protein contents was observed in X-Jigna suggesting that X-Jigna is the most tolerant among all the rice cultivars tested against Pb-stress.On the other hand,non-significant and slightly significant increase in the antioxidant activity,less accumulation of proline and sucrose contents,and higher reduction in the chlorophyll and protein contents was observed in Ediget,which further suggest that Ediget is the most susceptible rice cultivar to Pb-stress.In addition,the other rice cultivars Furat and Amber 33,were found to be moderately tolerant to Pb-induced oxidative stress.In summary,our results suggest that tolerance to Pb-induced oxidative stress would be a result of a synergetic action of both enzymatic and non-enzymatic antioxidant systems,leading to a balanced redox status in rice.展开更多
[ Objective] The study was to investigate residual regularity in tissues of layer after combined exposure to lead （Pb） and/or cadmium （ Cd ）. [ Method] I.aad acetate （100 mg/L） and/or cadmium chloride （50 mg/L...[ Objective] The study was to investigate residual regularity in tissues of layer after combined exposure to lead （Pb） and/or cadmium （ Cd ）. [ Method] I.aad acetate （100 mg/L） and/or cadmium chloride （50 mg/L） were administered in drinking water to 120 individuals of 40 -week -old hyline layers for 8 weeks. [ Result] Compared with the Cd group, the Cd content in various tissues, except kidney and femur, in Cd ＋ Pb group all increased, but the difference was not significant （P 〉 0.05 ）. The Cd contents in kidney and femur in Cd group were significantly higher than that in Cd ＋ Pb group. Compared with the group Pb, the Pb contents in breast muscle and kidney in Cd ＋ Pb group decreased significantly （ P 〈 0.05 ） ; the Pb contents in femur decreased extremely （ P 〈 0.01 ） ; while the Pb contents in leg muscle, heart and spleen increased significantly （ P 〈 0.05 ） ; the Pb contents in liver and glandular stomach were almost the same. Compared with the control group, the Cd content in various tissues in Pb group increased significantly （ P 〈 0.05 ） ; no significant changes were observed for Pb content in Cd group. [ Conclusion] Deposit of Pb and Cd in poultry body had complex interaction.展开更多
Erdaohezi lead-zinc deposit belongs to the Derbugan metallogenic belt lying on the northwestern Hailaer-Genhe Mesozoic volcanic basin,located on the western slope of the Da Hinggan Mountains. The deposit is considered...Erdaohezi lead-zinc deposit belongs to the Derbugan metallogenic belt lying on the northwestern Hailaer-Genhe Mesozoic volcanic basin,located on the western slope of the Da Hinggan Mountains. The deposit is considered as one of the hypabyssal low-temprature hydrothermal lead-zinc deposits associated with volcanism. In order to lay the foundation on studying its diagenesis and mineralization ages,the detailed studies were carried out by dating the host rocks( i. e. rhyolitic lithic-crystal tuffs) using zircon LA-ICP-MS U-Pb method.The dating results show three groups of ages. The first group is the captured zircons( the weighted mean ^(206)Pb /^(238) U age as 175. 6 ± 2. 3 Ma,MSWD = 0. 70,n = 3). The second group can be regarded as the rockforming age( the weighted mean ^(206)Pb /^(238) U age as 165. 3 ± 1. 9 Ma,MSWD = 2. 40,n = 14). The third group should represent the late stage of the magmatic evolution( the weighted mean ^(206)Pb /^(238) U age as 161. 0 ± 3. 1Ma,MSWD = 0. 86,n = 4). According to the ages and the crystal form or CL image characteristics of zircons,it is determined that the diagenesis occurred in the late Middle Jurassic. Based on the regional geology and geochronological research,the acidic pyroclastic rocks are space accompaniment and time connection with the Tamulangou Formation intermediate-mafic volcanic rocks. Both of them constitute the host rocks of the deposit together. The rock combination also provides favorable conditions for large-scale silver,lead and zinc mineralization in this area.展开更多
Water pollution is one of the most important issues of the 21<sup>st</sup> century. It takes place when the pollutants are being entered into a water reservoir without any treatment. Heavy metals are one o...Water pollution is one of the most important issues of the 21<sup>st</sup> century. It takes place when the pollutants are being entered into a water reservoir without any treatment. Heavy metals are one of the major harmful pollutants that exist in the water;therefore, it is necessary to remove these toxic metals to keep our environment safe. Biosorption is an ecofriendly and economical technique for the elimination of these toxic metals from polluted water. In this research work roots, stems, and leaves of Momordica charantia (Bitter gourd) were used as biosorbent for the elimination of Pb (II) ions from aqueous solution. Many different parameters such as metal ion solution pH, biomass dosage, initial metal ions concentration and contact time were optimized in the batch experiments. The calculated results revealed that biosorption of Pb (II) was maximum at solution pH 5, biosorbent dosage of 0.1 g and 100 ppm of initial metal ions concentration within 240 minutes of contact time. M. charantia’s leaves showed the highest level of lead biosorption capacity (47.62%), followed by stems (42.36%) and roots (38.47%). The Freundlich isotherm and pseudo-second order kinetics model fitted well for the analytical data. The results indicated that Momordica charantia is an effective biosorbent for Pb (II) ions elimination from wastewater.展开更多
基金financially supported by the National Key Research and Development Program of China (2016YDF0800707)the National Key Technology R&D Program of China (2015BAD05B03)the National Natural Science Foundation of China (41271490)
文摘Lead （Pb） contamination has often been recorded in Chinese field soils. In recent years, efforts have been made to inves- tigate Pb toxicity thresholds in soils with plant growth and microbial assays. However, the influence of soil properties on Pb toxicity impacts on soil microbial processes is poorly understood. In this study ten soils with different properties were collected in China to investigate the relationships between thresholds of Pb toxicity to soil microbes and soil properties. The effect of soil leaching on Pb toxicity was also investigated to determine the possible influence of added anions on Pb toxicity during dose-response tests. Toxicity was inferred by measuring substrate-induced nitrification in leached and non-leached soils after Pb addition. We found that soil microbe Pb toxicity thresholds （ECx, x=10, 50） differed significantly between the soils; the 10% inhibition ratio values （ECI0） ranged from 86 to 218 mg kg-1 in non-leached soils and from 101 to 313 mg kg in leached soils. The 50% inhibition ratio values （EC50） ranged from 403 to 969 mg kg^-1 in non-leached soils and from 494 to 1 603 mg kg^-1 in leached soils. Soil leaching increased EC50 and EC50 values by an average leaching factor （LF） of 1.46 and 1.33, respectively. Stepwise multiple regression models predicting Pb toxicity to soil microbes were developed based on ECx and soil properties. Based on these models, soil pH and organic carbon are the most important soil properties af- fecting Pb toxicity thresholds （R2〉0.60）. The quantitative relationship between Pb toxicity and soil properties will be helpful for developing soil-specific guidance on Pb toxicity thresholds in Chinese field soils.
基金supported jointly by the National Natural Science Foundation of China (No.40903021)the Funding Project for Western Doctors of "Light of Western China" under the Talents Cultivation Program sponsored by the Chinese Academy of Sciences+2 种基金the "Eleventh Five-Year Plan" Key Project of National Science and Technology Supporting Plan(2006BAB07B04-04)the Innovation Project of theChinese Academy of Sciences (KZCX2-YW-107-6)the Research Project of the State Key Laboratory of Ore Deposit Geochemistry
文摘The polymetallic(Pb,Zn,Cu,etc) ore belt on the southwestern margin of Tarim is one of the major regions with the greatest prospecting potential in Xinjiang.Reported in this paper are the lead isotope data for 66 sulfide samples(including 50 galena samples,15 chalcopyrite samples and 1 pyrite sample) collected from such representative deposits as Tamu,Tiekelike,Kalangu,Abalieke,etc.in this ore belt.The Pb isotopic ratios of 206 Pb/204 Pb,207 Pb/204 Pb and 208 Pb/204 Pb in the galena samples range from 17.931 to 18.176,15.609 to 15.818 and 38.197 to 38.944,with the average values of 18.017,15.684 and 38.462,respectively.Those in the chalcopyrite samples range from 17.926 to 18.144,15.598 to 15.628 and 38.171 to 38.583,with the average values of 18.020,15.606 and 38.262,respectively.The pyrite sample has the Pb isotopic ratios of 206 Pb/204 Pb,207 Pb/204 Pb and 208 Pb/204 Pb to be 17.980,15.604 and 38.145,respectively.In combination with the previous Pb isotope data for sulfides,it is found that there is only a slight variation in the Pb isotopic composition of galena,chalcopyrite,sphalerite and pyrite in the ore belt.However,there is some difference in Pb isotopic characteristics between galena and chalcopyrite,especially the Pb isotopic composition of galena shows an obvious linear correlation with some other relevant parameters(e.g.β and γ).The comprehensive analysis suggested that lead in galena(maybe including sphalerite and pyrite) was derived principally from wall rocks and underlying basement,and that in chalcopyrite only originated from the basement.The single-stage model ages of these sulfides couldn't indicate the time limit of metallogenesis(Pb,Zn,Cu,etc.),and the positive linear correlations for the Pb isotopic composition of galena are of no single-stage and two-stage Pb-Pb isochron significance.Furthermore,there are significant differences in Pb isotopic composition characteristics between the genetic type of deposits in this polymetallic ore belt and the Mississippi Valley type(MVT).In addition,the authors also pointed out that there is a phenomenon of differentiation(not paragenesis) for lead and copper elements during the process of metallogenesis in this ore belt.
基金supported jointly by the Bureau of Resources and Environment,Chinese Academy of Sciences(KZCX3-SW-125)the National Natural Science Foundation of China(Grant No,40172037).
文摘The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic rcworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentary- metamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks arc introduced and compared with the orc-lead composition, so as to constrain the source of the ore lead. The result indicates that （1） sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their ^206pb/^204pb ratios arc within a range of 17.027- 17.317; ^207Pb/^204pb ratios, 15.451-15.786 and ^208Pb/^204pb ratios, 36.747-37.669; （2） the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks arc characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range, reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; （3） the sedimentary-metamorphic rocks in the mining district arc characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios arc obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic rcworking of these rocks; （4） Pb isotopic compositions of Late Proterozoic diorite-gabbro and Hercynian granite are higher than those of ores. Meanwhile, the Pb isotopic compositions of sulfides in the small-sized strata-penetrating mineralized veinlets formed at later stages arc completely consistent with that of sulfides in stratiform-banded ores, suggesting that these veiniets arc the product of autochthonous rcworking of the stratiform-banded ores during the period of metamorphism and the late magmatic superimposition-mineralization can be excluded; （5） amphibolite, whose protolith is basic volcanic rocks, has the same Pb isotopic compositions as ores, implying that ore lead was derived probably from basic volcanism. So, the source of ore-forming materials for the Huogeqi deposit is like that of the volcanic massive sulfide （VMS） deposits. However, the orebodies do not occur directly within the volcanic rocks, and instead they overlie the volcanic rocks, showing some differences from those typical VMS-type deposits.
基金a grant from the Next-Generation BioGreen 21 Program(SSAC,Grant No.PJ01342501),Rural Development Administration,Republic of Korea.
文摘In rice,high concentration of lead(Pb)can cause phyto-toxicity affecting several physiological functions.Cultivation of rice varieties that are resistant to Pb-induced oxidative stress is an important management strategy in Pb-contaminated soils.In the current study,we evaluated four different rice cultivars for their response to Pb-induced stress.Three japonica type cultivars X-Jigna,Ediget,and Furat,and one Indica type cultivar Amber 33 were grown in soil containing different Pb concentrations(0 mM,0.6 mM,and 1.2 mM).The soil was treated with 0 mM or 0.6 mM or 1.2 mM Pb solution one month prior to rice seedling transplantation.Thereafter,four-week-old rice seedlings were transplanted into the treated soil and their responses were observed until maturity.The data revealed that a highest concentration of Pb(1.2 mM)induced significant reduction in agronomic traits such as plant height,number of tillers per plant,number of panicles per plant,and number of spikelets per panicle in all the rice cultivars.However,least reduction in the agronomic traits was observed in X-Jigna,whereas the highest reduction in the agronomic traits was observed in Ediget.Antioxidant activity of catalase(CAT),peroxidase(POD),polyphenol oxidase(PPO),and superoxide dismutase(SOD),was evaluated along with the accumulation of superoxide ions(O2.-),protein,proline,chlorophyll,sucrose,glucose,and fructose contents in all the rice cultivars.A significant increase in antioxidant activity and in the accumulation of proline and sucrose contents with the least reduction in the chlorophyll and protein contents was observed in X-Jigna suggesting that X-Jigna is the most tolerant among all the rice cultivars tested against Pb-stress.On the other hand,non-significant and slightly significant increase in the antioxidant activity,less accumulation of proline and sucrose contents,and higher reduction in the chlorophyll and protein contents was observed in Ediget,which further suggest that Ediget is the most susceptible rice cultivar to Pb-stress.In addition,the other rice cultivars Furat and Amber 33,were found to be moderately tolerant to Pb-induced oxidative stress.In summary,our results suggest that tolerance to Pb-induced oxidative stress would be a result of a synergetic action of both enzymatic and non-enzymatic antioxidant systems,leading to a balanced redox status in rice.
基金National Quality Safety Risk Assessment of Agricultural Products Program(GJFP2016007)Research Fund for the Doctoral Program of Jiangsu Institute of Poultry Science(JQ201201)+2 种基金Yangzhou Prospective Study of Agriculture Fund(yz2014145)Jiangsu Sanxin Agriculture Engineering(SXGC[2016]292,SXGC[2015]298)General Program of Natural Science Foundation of Jiangsu Province(BK20131235)
文摘[ Objective] The study was to investigate residual regularity in tissues of layer after combined exposure to lead （Pb） and/or cadmium （ Cd ）. [ Method] I.aad acetate （100 mg/L） and/or cadmium chloride （50 mg/L） were administered in drinking water to 120 individuals of 40 -week -old hyline layers for 8 weeks. [ Result] Compared with the Cd group, the Cd content in various tissues, except kidney and femur, in Cd ＋ Pb group all increased, but the difference was not significant （P 〉 0.05 ）. The Cd contents in kidney and femur in Cd group were significantly higher than that in Cd ＋ Pb group. Compared with the group Pb, the Pb contents in breast muscle and kidney in Cd ＋ Pb group decreased significantly （ P 〈 0.05 ） ; the Pb contents in femur decreased extremely （ P 〈 0.01 ） ; while the Pb contents in leg muscle, heart and spleen increased significantly （ P 〈 0.05 ） ; the Pb contents in liver and glandular stomach were almost the same. Compared with the control group, the Cd content in various tissues in Pb group increased significantly （ P 〈 0.05 ） ; no significant changes were observed for Pb content in Cd group. [ Conclusion] Deposit of Pb and Cd in poultry body had complex interaction.
基金Supported by National Natural Science Foundation of China(No.41390444)
文摘Erdaohezi lead-zinc deposit belongs to the Derbugan metallogenic belt lying on the northwestern Hailaer-Genhe Mesozoic volcanic basin,located on the western slope of the Da Hinggan Mountains. The deposit is considered as one of the hypabyssal low-temprature hydrothermal lead-zinc deposits associated with volcanism. In order to lay the foundation on studying its diagenesis and mineralization ages,the detailed studies were carried out by dating the host rocks( i. e. rhyolitic lithic-crystal tuffs) using zircon LA-ICP-MS U-Pb method.The dating results show three groups of ages. The first group is the captured zircons( the weighted mean ^(206)Pb /^(238) U age as 175. 6 ± 2. 3 Ma,MSWD = 0. 70,n = 3). The second group can be regarded as the rockforming age( the weighted mean ^(206)Pb /^(238) U age as 165. 3 ± 1. 9 Ma,MSWD = 2. 40,n = 14). The third group should represent the late stage of the magmatic evolution( the weighted mean ^(206)Pb /^(238) U age as 161. 0 ± 3. 1Ma,MSWD = 0. 86,n = 4). According to the ages and the crystal form or CL image characteristics of zircons,it is determined that the diagenesis occurred in the late Middle Jurassic. Based on the regional geology and geochronological research,the acidic pyroclastic rocks are space accompaniment and time connection with the Tamulangou Formation intermediate-mafic volcanic rocks. Both of them constitute the host rocks of the deposit together. The rock combination also provides favorable conditions for large-scale silver,lead and zinc mineralization in this area.
文摘Water pollution is one of the most important issues of the 21<sup>st</sup> century. It takes place when the pollutants are being entered into a water reservoir without any treatment. Heavy metals are one of the major harmful pollutants that exist in the water;therefore, it is necessary to remove these toxic metals to keep our environment safe. Biosorption is an ecofriendly and economical technique for the elimination of these toxic metals from polluted water. In this research work roots, stems, and leaves of Momordica charantia (Bitter gourd) were used as biosorbent for the elimination of Pb (II) ions from aqueous solution. Many different parameters such as metal ion solution pH, biomass dosage, initial metal ions concentration and contact time were optimized in the batch experiments. The calculated results revealed that biosorption of Pb (II) was maximum at solution pH 5, biosorbent dosage of 0.1 g and 100 ppm of initial metal ions concentration within 240 minutes of contact time. M. charantia’s leaves showed the highest level of lead biosorption capacity (47.62%), followed by stems (42.36%) and roots (38.47%). The Freundlich isotherm and pseudo-second order kinetics model fitted well for the analytical data. The results indicated that Momordica charantia is an effective biosorbent for Pb (II) ions elimination from wastewater.
