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1.
It is generally thought that phosphine (PH3) concentrations exist at the low ng/m3 level during the night and at the pg/m3 level during daylight in the remote atmosphere of the lower troposphere. The first de- termination of gaseous PH3 on the Antarctic Millor Peninsula is reported in this paper. No PH3 was de- tected in the air samples around 10:00 when it was sunny. However, PH3 was found in all the 10:00 air samples when it was cloudy or light snow with the average of 75.3±28.8 ng/m3 (n=5). It was also found in nearly all the samples around 22:00 with the average of 87.2±70.9 ng/m3 (n=11). Atmospheric PH3 concentrations around 22:00 were generally higher than those around 10:00 in January and they were almost the same in February. In addition, PH3 concentrations around 22:00 showed a downtrend with the decreasing air temperature, suggesting that light intensity and air temperature had an important effect on atmospheric PH3 concentration. It is very surprising to have found that high concentrations of PH3 exist in the Antarctic atmosphere under the influence of strong UV-radiation and light intensity. The tentative analyses show that dry, cold and very clean atmosphere may be very suitable for the PH3 sur- vival and cause the concentration to increase and accumulate in the local atmosphere. New ap- proaches for the PH3 formation and the process of atmospheric chemistry may exist under such an extreme environment. Atmospheric PH3 may also be from the emissions of local sources.  相似文献   

2.
Matrix-bound phosphine (PH3),a new form of phosphorus,was found in sediment of Jiaozhou Bay in December 2001,Concentration and distribution of PH3 in different layers of sediment with different stations were analyzed.The results show that PH3 concentrations are various with different layers and different stations.PH3 concentrations in the bottom layer of sediment (20-30 cm) are usually higher than those in the surface layer (0-4cm) ,The highest PH3 concentration in our investigation reaches 685 ng/kg (dry),which is much higher than those in terrestrial paddy soil ,marsh and landfill that have been reported up to now,The correlation analysis indicates that there is no apparent correlation between the concentrations of PH3 and inorganic phosphorus in sediment.However,the correlation between the concentrations of phosphine and organic phosphorus in the bottom layer of sediment is remarkable (R^2=0.83).It is considered that PH3 in sediment of Jiaozhou Bay is mainly produced from the decomposition of organic phosphorus in the anaerobic condition,and so PH3 concentrations are related to organic phosphorus concentration and anaerobic environment in sediment,The discovery of PH3 in sediment will give people some new ideas on the mechanisms of phosphorus supplement and biogeochemical cycle in Jiaozhou Bay.  相似文献   

3.
<正> In this paper,we use pre-column 2 times low-temperature cryo-trap enrichment—gas chromatography(GC) /nitrogen and phosphoms detector(NPD)to detect and analyze phosphine in Arctic pole area forthe first time.The results show phosphine exists in all of the samples in Arctic pole biosphere and phosphineconcentration in Arctic atmosphere is between 18.54~132.18 ng/m~3,almost the same as that inAntarctic atmosphere;phosphine concentration in Dalian bay sea surface sediments is between 116.8~554.3 ng/kg,almost the same as that reported in Jiao-zhou bay.Our research of phosphine will shednew light on the mechanisms showing how the phosphorus supplement influences the biogeochemical cycleand global warming.  相似文献   

4.
The type, size, and compositions of fluid inclusions in a natural sphalerite were investigated and the total concentration of Zn released from the fluid inclusions was measured. To compare the total concentration of Zn released from the fluid inclusions with that dissolved from the sphalerite itself, dissolution experiments and theoretical calculations for the dissolution equilibrium of the sphalerite were also performed. The results indicate that large numbers of fluid inclusions with various sizes exist in the sphalerite, which can be divided into four types, i.e., pure gaseous inclusions, pure liquid inclusions, gas-liquid inclusions, and gas-liquid inclusions containing solid minerals. These inclusions were broken open during the grinding process, and their compositions were released to the solution. The total concentration of Zn released from these inclusions reaches 18.35×10?6 mol/L, which is much higher than that of Zn dissolved from the sphalerite itself (1.93×10?6 mol/L) and the theoretical calculation value (2.73×10?8 mol/L).  相似文献   

5.
The main purpose of this work was to develop an assay as a means of quality control in milk and dairy products. As specific and high abundant proteins in milk and diary products, casein and β-lactoglobulin were chosen as the targets, and an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for determination of the total concentration of casein and β-lactoglobulin. The detection limit of the assay was 79.07 ng/mL, and a working range of the calibration curve was from 140.6 to 36,000 ng/mL. The intrassay and inter-assay coefficients of variations were 4.7 % and 6.5 %, respectively. The recoveries ranged from 94.1% to 106.6 %. The developed ELISA assay was used to detect the total con- centration of casein and β-lactoglobulin in liquid milk and milk powder. The results indicated that the developed assay was very specific, and the addition of nonprotein nitrogen (such as melamine, cyanuric acid, and urea) and vegetable protein did not affect the detection. The good performance of the assay makes it suitable for use in the quality control of milk and dairy products.  相似文献   

6.
The mechanism of carbon isotopic fractionation for gaseous hydrocarbons is revealed by investigating the residual liquid hydrocarbons in laboratory pyrolysates of n-octodecane. The results indicate that cracking and polymerization in the relatively low temperatures and dispropor-tionation reactions leading to light hydrocarbons and pol-yaromatic hydrocarbons at high temperatures are probably causes for the carbon isotope reversal of gaseous hydrocarbons that is commonly observed in pyrolysis experiments. This study provides significant insight for quantitative modeling of natural gas δ13C values and aid in the identification and assessment of natural gases derived from oil cracking.  相似文献   

7.
Occurrence of perfluoroalkyl acids in precipitation from Shenyang, China   总被引:2,自引:0,他引:2  
Perfluorosulfonates (PFSAs) and perfluorocarboxylates (PFCAs) in precipitation collected from Shenyang, China were determined. Snow samples were collected in the snow event on March 4, 2007 from 34 sites involving both the urban and suburban areas in Shenyang. The snowmelt was preconcentrated by solid phase extraction and analyzed using LC-MS method. Measurable amounts of perfluoroalkyl acids (PFAS) were found in precipitation samples from Shenyang, demonstrating that wet deposition is one possible pathway for the removing of the selected PFAS chemicals from atmosphere. Major PFAS detected were PFOS (〈0.38-51 ng/L), PFOA (0.82-13 ng/L) and PFHpA (0.76-11 ng/L), with their mean concentration of 5.4, 3.3 and 2.9 ng/L, respectively. Other PFSAs and PFCAs were detected at much lower frequency or below the limit of detection in all the samples. The work presented here offers some basis for the investigation on the environmental behavior and the evaluation of human exposure to PFAS.  相似文献   

8.
Polychlorinated diebenzo-p-dioxins (PCDDs), polychlorinated diebenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were monitored in the ambient air of Taizhou, an E-waste dismantling area of southeast China to evaluate their concentrations, profiles and gas-particle partitioning. The ∑PCDD/Fs concentrations ranged from 2.91 to 50.6 pg/ma, with an average of 14.3 pg/ma. The I-TEQs for PCDD/Fs were in the range of 0.20-3.45 pg/ma, with an average of 1.10 pg/ma, The ∑PCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/ma, 0.050 to 0.859 pg(TEQ)/ma, respectively. The concentrations of ∑PBDEs ranged from 92 to 3086 pg/ma, with an average of 894 pg/ma, The pollution levels of PCDD/Fs, PCBs and PBDEs were higher than other urban sites, which may be associated with the E-waste dismantling activities. The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase. The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient (Kp) with the subcooled liquid vapor pressure (pL^0). The measured particulate sorptions of PCDD/Fs, PCBs and PBDEs were compared with the predictions from Junge-Pankow model and Koa absorption model. The Junge-Pankow model well estimated the particulate fractions of PCBs. However, it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs. The predicted particulate fractions of PCDD/Fs and PCBs from Koa model fitted well with the measured data.  相似文献   

9.
Dioxin-like polychlorinated biphenyls(PCBs) are a class of toxic and persistent chemicals that are often found in the environment.The determination of dioxin-like PCBs in Fildes Peninsula,Antarctica,is reported in this paper.Dioxin-like PCBs were widely distributed in Antarctic soil and moss with concentration of 2.23-27.2 pg/g in soil and 10.4-812 pg/g in moss.The highest concentrations were found in the Ardley Island area and the lowest concentrations on the west coast.The contribution of PCB-118 to the ∑12PCBs ranged from 36.0% to 69.6% in soil,and 17.2% to 43.4% in moss.The congener specific patterns in soil and moss were similar.Long-range atmospheric transport is thought to be the main source of PCBs detected on King George Island.The ∑12PCBs toxic equivalent(TEQ) in soil was 0.400×10?3 to 516×10?3 pg(TEQ)/g with a mean value of 147×10?3 pg(TEQ)/g.PCB-126 had the largest contribution(81.1%) to the ∑12PCBs TEQ in soil.The ∑12PCBs TEQ in moss ranged from 2.90×10?3 to 1.19 pg/g with a mean value of 0.482 pg/g.PCB-126 was also the largest contributor(91.4%) to the ∑12PCBs TEQ in moss.The mean TEQ in moss was about 40 times that in soil.  相似文献   

10.
The eco-physiological response and adaptation of Populus euphratica Oliv and Tamarix ramosissima Ldb during water release period were investigated. Nine typical 'areas and forty-five transects were selected along the lower reaches of Tarim River. The groundwater table as well as plant performance and the contents of proline, soluble sugars, and plant endogenous hormone (ABA, CTK) in leaves were monitored and analyzed. The groundwater table was raised in different areas and transects by water release program. The physiological stress to P. euphratica and T. ramosissima had been reduced after water release. Our results suggested that the groundwater table in the studied region remained at -3.15 to -4.12 m, theproline content from 9.28 to 11.06 (mmol/L), the soluble sugar content from 224.71 to 252.16 (mmol/L), the ABA content from 3.59 to 5.01 (ng/g FW), and the CK content from 4.01 to 4.56 (ng/g FW), for the optimum growth and restoration of P. euphratica indicated by the plant performance parameters and the efficiency of water application was the highest. The groundwater table in the studied region remained at -2.16 to -3.38 m, the proline content from 12.15 to 14.17 (mmol/L), the soluble sugar content from 154.71 to 183.16 (mmol/ L), the ABA content from 2.78 to 4.86 (ng/g FW), and the CK content from 3.78 to 4.22 (ng/g FW), for the optimum growth and restoration of T. ramosissima indicated by the plant performance parameters and the efficiency of water application was the highest. The rational groundwater table for the restoration of vegetation in the studied region was at -3.15 to -3.38 m.  相似文献   

11.
The spectral absorption coefficient of phytoplankton in coastal waters of southern China is investigated. Large variations in the absorption coefficient of phytoplankton are found. The absorption coefficient of phytoplankton at 443 nm ranged from 0. 006 m- 1 to 0. 484 m - 1, with an average value of 0. 067 m - 1. The chlorophyll-specific absorption coefficient of phytoplankton is also a bio-optical varito pigment composition of phytoplankton and package effect. The chlorophyll-specific absorption coefficient of phytoplankton decreases with the increasing of chlorophyll a concentration. This relationship can be described by a power law function, with the parameters and the coefficient of determination r2 as functions of wavelength, but the parameters describing the relationships in present study differed from that in Case 1 waters, thus the regional adjustment of model parameters was of particular significance for improving the accuracy of bio-optical algorithms for estimation of Chl-a concentration and primary production from remotely sensed data. Regression analysis of reflectance (R rs) ratio and absorption coefficient of phytoplankton (a ph) indicates a close correlation between them, which means that it is possible to retrieve absorption coefficient of phytoplankton using ocean color remote sensing data in optically complex coastal waters.  相似文献   

12.
PCDD/Fs in the urban air of Dalian,China were monitored with high-volume active sampler from November 2009 to October 2010.The concentration of Cl 4-8 DD/Fs ranged from 3065 to 49538 fg m-3,with an average of 10249 fg m-3.The international toxic equivalents(I-TEQ) value of that was 61.8 1182 fg m-3,with an average of 235 fg m-3,which was comparable to those in the other urban locations around the world.It was found that the Cl 4 8 DD/Fs appeared to be present mainly in the particle phase during winter,spring and autumn,while during summer which were dominantly in gas phase.The ratio of Cl 4-8 DD/Fs present in particle phase increased with the increasing level of chlorination.The concentrations of PCDFs and PCDDs decreased with the increase of chlorinated level,while the concentrations of 2,3,7,8-PCDDs congeners increased with the increase of chlorination level.The homolog profiles of the concentrations of PCDFs presented were higher than those of the PCDDs,which indicated the PCDD/Fs pollution source of the air in Dalian was characteristic for thermal source pollution.The correlation analysis of meteorological parameters with the concentrations of Cl 4-8 CDD/Fs was conducted using SPSS packages,and it was found that the ambient temperature and atmospheric pressure were important factors influence the concentration of PCDD/Fs in the air.The respiratory risk and intake dioxins of the residents around the sampling sites were studied in the paper.It was found that Junge-Pankow model was much more accurate in predicting the gas-particle partitioning behavior of PCDD/Fs homologues during winter,while the Harner-Bidleman model shows better agreement with the measured data during winter and summer.  相似文献   

13.
Effect of land use on microbial biomass-C, -N and -P in red soils   总被引:1,自引:0,他引:1  
Eleven red soils varying in land use and fertility status were used to examine the effect of land useon microbial biomass -C, -N and -P. Microbial biomass-C in the red soils ranged from about 68 rag C/kg to 225 mg C/kg, which is generally lower than that reported from other types of soil, probably because of low or-ganic matter and high acidity in the red soils. Land use had considerable effects on the amounts of soil Cmic.The Cmic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest in vegetable and paddy fields. There was significant correlation between Cmic and organic matter content, suggesting that the influence of land use on Cmie is mainly related to the input and ac-cumulation of organic matter. Microbial biomass-N in the soils ranged from 12.1 Nmg/kg to 31.7 Nmg/kg andwas also affected by land use. The change of Nmic with land use was similar to that of Cmic. The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. The Nmic was significantly correlated with soil total N and available N. Microbial biomass-P in the soils ranged from 4.5 mg P/kg to 52.3 rag P/kg. The microbial C/P ratio was in the range of 4-23. The Pmic was relatively less affected by land use due to differences in fertili-zation practices for various land use systems.  相似文献   

14.
The average mass concentration of the aerosols in Beijing during the dust storm in the spring of 2000 was ~6000 mg·m-3, ~30 times as high as that in the non-dust storm days. The enrichment factors of the pollution elements As, Sb and Se were higher than those in the non-dust storm days. This indicated that As, Sb and Se resulted from the pollution sources of those areas, through which the dust storm passed during their long-range transport, in addition to the local pollution sources in Beijing. The enrichment factors of the Pb, Zn, Cd and Cu were much less than those in the non-dust storm days, suggesting that the local pollution sources in Beijing area contributed to them mostly. The enrichment factors of elements Al, Fe, Sc, Mn, Na, Ni, Cr, V and Co were close to 1, showing that these elements originated from crust. The concentration of S in the dust storm was ~10 mg·m-3, 4 times as high as that in non-dust storm. S in the aerosols resulted from the adsorption of gaseous SO2 and the consequent transformation on it. The aerosols of the dust storm contained 16.1% and 76.9% of fine particles with the sizes less than 2.1 and 9.0 mm, respectively, while it had a large number of coarse particles. It was noted that a considerable portion of Fe(Ⅱ) was detected from the dust storm. Fe(Ⅱ) could easily dissolve in seawater to be nutrient for phytoplankton and would lead to the increase of the emission of dimethylsulfide (DMS) from the ocean. The feedbacks of Fe coupled with S in atmosphere might be the important mechanism that would affect the primary productivity in Pacific and/or the global climate change.  相似文献   

15.
The southern part of the Haihe River system, the largest river system in the Haihe River Basin, is important to maintain a healthy ecosystem and safe drinking water as well as for the economic development of China. To assess the effect of rapid industrialization and urbanization on the pattern of polycyclic aromatic hydrocarbon (PAH) contamination, the PAH pollution characteristics of the southern part of the Haihe River system was investigated. Sixteen PAHs in surface sediments samples collected from 24 sites covering the southern part of the Haihe River system from the upstream to the estuaries were detected and analyzed. The total PAH concentration ranged from 258.77 to 11296.66 ng/g dry weight. On average, 2-, 3-, 4-, 5and 6-ring PAHs comprised 25.32%, 27.22%, 22.62%, 14.89% and 9.96% of the total PAHs, respectively. Sites with high concentrations were concentrated in the Fuhe River, Fuyang River and Wei River, which are located near cities. A risk quotient (RQ) was used to assess the ecological risk of PAHs. The mean values of the RQ(MPCs) of individual PAHs were lower than 1.00, except for those of naphthalene (2.00) and pyrene (1.67). The RQPAHs calculated for the samples indicated that the Xidayang reservoir and the estuary of the Ziya River were determined to be at a low risk level, while Baoding City, Handan City and Aixinzhuang were determined to be at a high risk level.  相似文献   

16.
Zhai  Wei  Sun  XiaoMing  Wu  YunShan  Sun  YanYan  Hua  RenMin  Ye  XianRen 《科学通报(英文版)》2012,57(10):1150-1159
Isotopic abundances and ratios of He and Ar found in inclusion fluids in pyrites formed in the Yaoling-Meiziwo tungsten miner-alization epoch show that the concentration of 4He varies widely,from 1.54×10-7 cm3 STP/g to 2609×10-7 cm3 STP/g.3He is 0.759×10-12 cm3 STP/g-3.463×10-12 cm3 STP/g.3He/4He is 0.0043-4.362 Ra,varying from crustal to mantle values.The concen-tration of 40Ar ranges from 0.624×10-7 cm3 STP/g to 8.89×10-7 cm3 STP/g.The 40Ar/36Ar varies extensively,from 330 to 2952,between atmospheric and crustal or mantle radiogenic values.Mantle-derived He is present in ore-forming fluids and the calcu-lated average proportion of the mantle He is 22%;the maximum is 67%.Our research results show that mantle-derived fluids play a significant role in tungsten mineralization.The fractionation of He and Ar indicate that there was 4He-enriched air-saturated water(MSAW) in the ore-forming fluid.The ore-forming fluid was a mixture of mantle fluid,crustal magmatic fluid and MSAW.The occurrence of a mantle component in ore-forming fluid indicates the large-scale W and Sn mineralization,including Yaol-ing-Meiziwo,in southeastern China was the result of crust and mantle interaction.The underplating or intrusion of voluminous basaltic magma formed by partial melting of the upper mantle provided the necessary heat to cause partial melting of the crust and the generation of voluminous S-type granitic magmas.Crustal magmatic fluid and mantle fluid with high 3He/4He were released from magma crystallization and fractionation,mixed with the circulating modified air-saturated water,and filled the extensional tectonic fractures,leading to the formation of world-class W and Sn deposits in southeastern China.  相似文献   

17.
During DY105-17 cruise onboard the PJV "Da Yang Yi Hao" in 2005, methane concentrations in the water column above Logachev hydrothermal vent field were measured by applying stripping/trapping-gas chromatographic (GC) and the distinct methane plumes were detected. Results show that the background methane concentration within the Logachev area is from 1.05 nmol/L to 1.68 nmol/L, significantly higher than the background level of the Atlantic abyssal plain of 0.4-0.5 nmol/L, suggesting that hydrothermal venting is a major source of dissolved methane to the ocean. The highest anomalies of methane concentrations in the water column range from 7.14 nmol/L to 113.9 nmol/L and occur just at 180-500 m above the seafloor. The distribution of methane concentration and the structural characteristics of hydrothermal plumes are strongly influenced by the supply of underlying hydrothermal fluids, the mixing process of ocean bottom currents and the microbial oxidation. Furthermore, the differences in distribution of methane plume between the station MAR-CTD3 and the other stations indicate a probable unknown hydrothermal vent site nearby. There occurs high concentration of methane along with temperature and nephelometry anomalies, which strongly confirms that the subtle measurement of methane concentration in water column is one of the effective ways to locate active sites of hydrothermal venting.  相似文献   

18.
Electrochemical measurements were conducted to study the electrochemical behavior of gold (Au) and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxidation peak appeared; the oxidation peaks of arsenopyrite and chalcocite appeared earlier than that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibnite. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.  相似文献   

19.
Cadmium-metallothionein (Cd-MT) of Pteria penguin was used to immunize domestic rabbit in order to obtain polyclonal antibody against Cd-MT. Using the anti-Cd-MT antibody, a method of indirect non-competitive enzyme-linked immunosorbent assay (non-competitive ELISA) was established to detect shellfish Cd-MT. In this case, the minimum detectable concentration of P. penguin Cd-MT was (4.563±0.051) ng/mL. The linear range of detection was 9.75-2.0×104 ng/mL. Intra-assay relative standard deviation (RSD) was less than 11.6%, and inter-assay RSD less than 6.7%. The recovery rates ranged from 83.7% to 119.0%. The polyclonal antibody against Cd-MT of P. penguin can also be used to detect MT of other four types of shellfish. In the crude extracts from different organs of P. penguin, the MT concentrations determined by this method matched well with the concentrations of cadmium detected by the atomic absorption spectroscopy.  相似文献   

20.
Sources of matrix-bound phosphine in advanced wastewater treatment system   总被引:2,自引:0,他引:2  
Phosphine (PH3), a highly toxic and reductive gas, has been explored in biogases and it proves also to be ubiquitous even in remote atmospheric air at a concentration in the order of (pg-ng) /m^3 [3]. For more than one hundred years, sources and mechanisms of biological phosphine formation in natural and engineered environments have been investigated and discussed. Anaerobic environments were reported to be the main source of phosphine emission.  相似文献   

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