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1.
The ubiquitous occurrence of perfluorinated compounds (PFCs) in environmental samples has drawn much attention. Recent human exposure studies found relatively high perfluorooctane sulfonate (PFOS) concentrations in blood samples from several cities in China when compared with other countries. The objectives of the present study were: (1) to measure PFC concentrations and compositions in chicken egg samples from local markets in China; and (2) to conduct a preliminary human health risk assessment of egg consumption. Eight pooled egg samples from eight locations were analyzed for 11 PFCs. The results showed that close to 100% of the PFOS in the egg was distributed in egg yolk and PFOS was not detected in egg white (〈0.08 ng/g wet weight, w/w). Of the perfluoroalkylsulfonates, only PFOS was detected in all egg samples, while of the perfluoroalkylcarboxylates, perfluoroundecanoic acid (PFUnDA) was detected in all samples, followed by perfluorooctanoate (PFOA) (75% occurrence) and perfluorodecanoic acid (PFDA) (50% occurrence). PFOS concentrations in egg ranged from 45.0 to 86.9 ng/g w/w. The results suggested that current concentrations of PFOS in domestic chicken eggs are unlikely to cause immediate harm to Chinese populations.  相似文献   

2.
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two typical perfluorinated compounds (PFCs), found in a wide range of environmental media and organisms, including humans. Human biomonitoring studies of body fluids have revealed that in many areas of the world the general population has been exposed to background levels of PFOS and PFOA. Fingernail has been suggested as a promising biopsy material for assessment of PFCs environmental exposure. In the present study, PFOS and PFOA were quantified using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in fingernails of urban and rural children (N=93) aged 6–12 years. A questionnaire was conducted to determine factors that could influence the PFOS and PFOA levels in the children. The levels of PFOS in urban children were significantly higher (geometric mean (GM)=328 ng/g) than those in rural children (GM=27 ng/g). In contrast, PFOA levels were significantly lower in the urban children compared with the rural children. Significant positive correlation (R=0.53, P<0.05 for urban areas; R=0.71; P<0.001 for rural areas) between the PFOS and PFOA concentrations indicated they had similar sources. The PFOS and PFOA levels were higher in fingernail samples from children aged <9 years than in children aged ⩾9 years. In addition, females had higher PFOA levels than males, in both regions. Other factors that significantly influenced PFOS and PFOA levels were dietary habits and socio-economic background. The results of this study indicate fingernails are a suitable material for biomonitoring of PFCs environmental exposure. However, the levels determined in the fingernail samples need to be first evaluated with regard to the levels determined in other samples, such as human serum.  相似文献   

3.
汉江水体和沉积物中全氟化合物的风险评估   总被引:2,自引:0,他引:2  
采集汉江旱季和雨季的水样和沉积物,应用超高效液相色谱–三重四级杆质谱,对其中的11种全氟化合物(PFCs)进行检测,研究该区域全氟化合物的污染状况。结果表明,11种全氟化合物都有不同程度的检出,旱季和雨季水样中∑PFCs浓度分别为0.3~23.04和0.16~19.68 ng/L,沉积物中∑PFCs浓度分别为0~55.1和0.99~85.07 ng/g。水样总浓度的最高值出现在汉江汇入长江处的武汉,且武汉采样点的全氟辛酸(PFOA)浓度最高,旱、雨季分别达到22.52和12.52 ng/L。沉积物中总浓度最高值出现在陶岔,且以全氟庚酸(PFHp A)和全氟己酸(PFHx A)为主,沉积物中组分组成的季节差异不大。采用实际检测到的水样中PFOA、全氟辛烷磺酸盐(PFOS)、全氟壬酸(PFNA)、PFHx A和全氟葵酸(PFDA)的浓度以及沉积物中PFOA和PFOS的浓度,运用熵值法,对汉江流域进行全氟化合物污染的风险评估,结果表明,水体和沉积物中的浓度均未达到对生态环境具有风险的水平。  相似文献   

4.
Formic (HCOOH) and acetic (CH3COOH) acids are the chief carboxylic compounds in the troposphere[1]. Although weak acids, they contribute significantly to the free acidity, ionic balance of precipitation and the chemical reactions in the atmosphere, especially in the remote areas[2—4]. General sources for formate and acetate have been identified in the past 3 decades although a satisfactory source attribution is lacking to explain atmospheric observations[5]. Possible sources include veget…  相似文献   

5.
The concentrations and species of organotin compounds(OTCs) in 52 surface sediment samples from nine fishing ports along the Chinese coast were studied.Butyltins(BTs) and phenyltins(PhTs) were derivatized using sodium tetraethylborate(NaBEt 4) and determined by head-space solid-phase microextraction(HS-SPME) gas chromatography coupled with a flame photometric detector(GC-FPD).The concentrations of OTCs ranged from <3.6 to 194 ng(Sn) g-1 dry weight(dw) for monobutyltin(MBT),<2.3 to 41.5 ng(Sn) g-1 dw for dibutyltin(DBT),<0.7 to 86.0 ng(Sn) g-1 dw for tributyltin(TBT) and <5.1 to 66.1 ng(Sn) g-1 dw for monophenyltin(MPhT),respectively.The concentrations of diphenyltin(DPhT) and triphenyltin(TPhT) were below the limit of detection(LOD).BTs were the main species in the sediments except for the samples collected from Shazikou fishing port in Qingdao.The concentrations of MBT were higher than DBT and TBT.The concentrations of OTCs in the sediments varied widely among different sampling locations.The concentrations of BTs were much higher in the samples collected from fishing ports close to the South China Sea than those in coast of the East China Sea and the Yellow Sea.MPhT was prevalent in most sampling stations except for those in coast of the East China Sea.The environmental and ecotoxicological risks of TBT in most sediment samples were low.  相似文献   

6.
In order to study the sus diets and explore the possibility to distinguish domestic pig from wild boar through dietary analysis, stable carbon and nitrogen isotopes of 28 pig bones from archaeological site of Wanfabozi in Tonghua City, Jilin Province were analyzed. The δ^13C and δ^15N values of uncontaminated bones show that the overall pigs in the site were generally herbivores and ate mainly C3 plants. Significant difference of δ^15N values was observed between wild boar and domestic pigs, which may result from the higher consumption of animal protein in domestic pigs other than from that in wild boar, possibly from human leftover or waste,. The dietary difference between wild boar and domestic pigs has great potential to differentiate wild boar and domestic pigs in the early stage of pig domestication.  相似文献   

7.
Tian  XiaoSi  Zhu  Cheng  Sun  ZhiBin  Shui  Tao  Huang  YunPing  Flad  Rowan Kimon  Li  YuMei 《科学通报(英文版)》2011,56(2):169-178
Based on AMS 14C dating data, carbon and nitrogen isotope analyses were conducted on mammal bone collagen of deer, cattle and pigs from the Zhongba site in the Three Gorges Reservoir region of the Yangtze River. These analyses were conducted to reconstruct palaeodiets of mammals, palaeoecology, palaeoenviroment and previous human activities in the study area. Results show that the collagen loss of bone did not change the in vivo isotopic composition of carbon and nitrogen stable isotopes, and most of the bone fossils were well preserved. The bone collagen of samples from deer had a mean δ13C of -23.1‰ and a mean δ15N of 4.7‰, suggesting that deer subsisted in a closed habitat and fed on branches and leaves. The bone collagen of cattle had a mean δ13C of –19.6‰ and a mean δ15N of 5.2‰, which indicates that cattle subsisted in an open habitat and fed on grasses and stems. The δ13C values show that both deer and cattle fed on C3 plants and lived in the same ecosystem, but the t-test results show that deer δ13C and δ15N values were both more negative than those of cattle, indicating that they inhabited different niches. The δ13C and δ15N values of cattle partially overlapped those of deer, suggesting some competition in diets between them. The t-tests show that the δ13C and δ15N values of pigs were more positive than those of cattle and deer, which signifies that pigs occupied a higher trophic level compared to cattle and deer. The wide range of pig δ13C values demonstrates that pig trading had been taking place from early Neolithic Age to late Bronze Age. There were no significant differences in deer δ13C and δ15N values among different archaeological periods, making it clear that climatic, ecological and environmental conditions were kept relatively stable from 2200 to 4200 a BP. This stability may have been responsible for the extensive and complete cultural layers at the Zhongba site. The minimum number of samples required to estimate the mean δ13C values of deer, pigs and cattle are 8, 73 and 16, respectively, and for mean δ15N values of deer, pigs and cattle, the minimum numbers are 4, 5 and 6, respectively.  相似文献   

8.
探究了鸡中铅同位素与相关元素在有机养殖和常规养殖中的差异性,以探讨有机鸡样品溯源的可能性。相同品种的鸡分别采用有机养殖和常规养殖2种不同的饲养方式,利用电感耦合等离子体质谱分别对有机鸡和普通鸡样品中的铅同位素比值和相关元素含量进行测定。方差分析结果表明,铅同位素比值204Pb/206Pb和P、Zn、Fe、Mn、Mg、Ca、Cu、Na、K元素含量具有显著性差异(p<0.05);主成分分析初步表明,Zn、Mn、Mg、Ca、Cu、Na、K为有机鸡和普通鸡样品中的特征无机元素;聚类分析可将鸡样品分为有机养殖和常规养殖两大类,通过判别分析所得模型的初始分组正确率为100.0%,交叉验证正确率为90.0%。利用铅同位素比值(204Pb/206Pb)、相关元素(P、Zn、Fe、Mn、Mg、Ca、Cu、Na、K)含量分析能够对有机鸡进行有效溯源识别,研究结果可为有机鸡的鉴别研究提供新的方法。  相似文献   

9.
Phoshpine (PH3), a volatile and toxic gas, has been proved to commonly exist in the environment. The determination of gaseous phosphine and its emission fluxes in Ny-Ålesund is reported in this paper. Results showed that gaseous phosphine exist in Arctic atmosphere commonly and the concentration of phosphine ranged from 16.3–600.2 ng/m3, with the maximum concentration of phosphine in tundra areas and the minimum in surface air of ocean. The concentration of phosphine ranged from 65.79–1259 ng/m3 in colliery atmosphere at different altitudes and the maximum was found in the center of colliery. Emission fluxes of phosphine were different in various Arctic areas. Emission fluxes of phosphine from protected areas, with average concentration of 32.13±5.353 ng m–2 h–1, were higher than from other areas. And the flux of phosphine from ocean was lower.  相似文献   

10.
To quantitatively determine tylosin and tilmicosin in edible animal tissues,a time-resolved fluoroimmunoassay(TRFIA) has been developed and validated.For this purpose,desmycosin-O-carboxymethoxylamine-BSA was fixed onto microtiter plates,standards and samples were loaded and,finally,diluted europium-labeled anti-tylosin antibodies were added.Results show that the limit of detection for tylosin was 0.03 ng mL-1 and that for tilmicosin was 0.05 ng mL-1.The recoveries were 73.6% to 120.5%,with coefficients of variation below 15.6% in various biological matrices spiked with tylosin and tilmicosin at concentrations of 50-200 ngg-1.There was good correlation(R2>0.99) between the TRFIA,an enzyme-linked immunosorbent assay and high performance liquid chromatography data.In conclusion,the new TRFIA is applicable to the detection of tylosin and tilmicosin and is an effective and economical method that will enable high-throughput sample screening.The method is expected to be widely applicable.  相似文献   

11.
The results of research on the effects of anions on the biosorption of microelement cations by the edible marine macroalga Enteromorpha prolifera in singleand multi-metal systems are discussed in this paper. It was shown that the maximum biosorption capacity (qmax) in a single-metal system of Co(II) ions decreased in the following sequence: Cl- (46.0 mg g-1) > SO42- (42.8 mg g-1) > NO3- (41.9 mg g-1). In multi-metal systems, in which the ratios of Cl-, NO3-, and SO42- were 0:0:4, 1:1:2, 3:0:1, and 4:0:0, there were clear differences among the biosorption capacities. In all the examined systems (other than the 0:0:4 system), inhibition of the binding of microelement cations by the macroalga was observed. In all the systems, the highest value of qmax was obtained for Cu(II) cations; the value ranged from 31.9 mg g-1 in 0:0:4 (SO42- only) to 18.2 mg g-1 in 4:0:0 (Cl-only).  相似文献   

12.
鸡马立克氏病病毒与大肠杆菌混合感染症的病原分离鉴定   总被引:1,自引:0,他引:1  
鸡呼吸道病流行病学调查的过程中,在韶关市某养鸡场观察到一群100日龄广西黄肉仔鸡发生了以呼吸道症状为主要临床表现的疾病,死亡率达10%.病理解剖学检查可见病鸡有单一或多器官肿瘤病变(4/8)、典型腹膜炎病变(3/8)和肿瘤与腹膜炎病变并存(2/8).在病鸡肿瘤组织切片中可见典型MD病理组织学变化.采用CEF接种方法,从有肿瘤和腹膜炎病鸡的羽髓液中分离到MDV.在病鸡的心、肝、脾等脏器分离到大肠杆菌O78血清型菌株.研究结果表明:HVT疫苗免疫鸡群MDV强毒株和E.coliO78血清型菌株以混合感染形式存在,病鸡出现以呼吸道症状为主的临床表现,死亡率明显增加.  相似文献   

13.
日粮能量水平对0~8周龄银香麻鸡生产性能的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
选用360只1日龄银香麻鸡(母),分为3组,每组120只,每组4个重复,每个重复30只。以高、中、低3种代谢能(13.20 M J/kg、12.54M J/kg、11.90M J/kg)日粮进行饲养试验和消化代谢试验,考察日粮能量水平对0~8周龄银香麻鸡生产性能的影响规律。试验结果表明:(1)日增重随着日粮能量水平提高而增加(P<0.05);(2)饲料采食量随着日粮能量水平提高而减少,而代谢能摄入量则随之增加(P<0.05);(3)耗料增重比随着日粮能量水平提高而减少(P<0.05),0~8周龄银香麻鸡,推荐使用代谢能为13.20M J/kg日粮;(4)鸡的增重可用方程Y=1/[1/1000 0.025×(0.491)t]预测。  相似文献   

14.
Gallium, Ge, V, and U are the associated valuable elements in coal. From the 1950s to the 1970s, some researchers in the departments of coal industry and mineral resources of China investigated these elements in coal during geological explorations. The enrichment mechanism and the environmental influence of trace elements in coal have been deeply studied in recent twenty years. With respect to the ore-forming theories and practical utilizations of metals in coal, germanium was furthest studi…  相似文献   

15.
Three new mixed-ligand Fe(II/III) complexes [Fe22–btec)(μ2–H2btec)(phen)2(H2O)2]n (1), [Fe2(btec) (phen)2(H2O)4] (2), and {[Fe(o-pha)(phen)(H2O)]•H2O}n (3) (phen=1,10-phenanthroline, o-H2pha=o-phthalic acid, H4btec=1,2,4,5-benzenetetracarboxylic acid) have been hydrothermally synthesized and detected by single crystal X-ray diffraction, showing that complexes (1) and (2) are both bridged by the betc4− ligands to form 1D chain and dinuclear structure and complex (3) is bridged by the o-pha groups to form 1D chain structure. The coordinated modes of the carboxyl groups adopt μ21η1ηη1η1 and μ22η1 respectively in com-plexes (2) and (3). The betc groups in complex (1) show two different coordinated modes: μ21η1η1η1 and μ21η1. In addition, the hydrogen bonds and π…π type interactions make the complex molecule further connect to three-dimensional and two-dimensional networks respectively. These complexes are detected by IR, UV-Vis-NIR and surface photovoltage spectrum (SPS). The SPS of complexes (1)–(3) indicate that there are positive SPV responses in the range of 300–600 nm and show p-type semiconductor characteristic. Because the structure, the valence and the coordinative environment of the Fe ions are all different in the three complexes, the intensity, position and the number of the response bands are different obviously. The results of SPS are corresponding with UV-Vis-NIR spectra.  相似文献   

16.
Although IFN-γ alone does not prime type I T helper cell (Th1) differentiation, the loss of IFN-γ signaling leads to impaired Th1 phenotype: IFN-γ receptor-deficient (Ifngr-/-) Th1 cells fail to permanently repress IL-4 expression. They can differentiate into IL-4-producing cells under Th2-inducing conditions. These observations suggest that IFN-γ signaling plays a critical role in si- lencing Il4 gene in Th1 cells and stabilizing Th1 phenotype. IFN-γ signaling has been further shown to inhibit IL-4 express...  相似文献   

17.
Using titrimetric method, enzymatic behavior of lipase AK against fullerene end-capped polycaprolactone (C60-PCL) was studied for the first time, compared with polycaprolactone (PCL). The results showed that degradation of both C60-PCL and PCL by lipase followed Mechaelis-Menten equation, with the degradation parameters of PCL and C60-PCL were 0.75 mg mL–1 and 0.16 mg mL–1 for Km, and 0.90 mL h–1 and 0.43 mL h–1 for Vmax, respectively. C60-PCL had a slower degradation rate than PCL under the same conditions. These data indicated that the introduction of fullerene enabled PCL hard to be degraded by lipase.  相似文献   

18.
Lithium iron phosphate coated with carbon (LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis (TG/DTA), X ray diffractometer (XRD), Element Analysis (EA) and Scanning electron microscope (SEM). We also studied the electrochemical properties of the material. The first discharge capacity of the LiFePO4/C is 121 mAh·g−1 at 10 mA·g−1, at room temperature. When the current density increased to 100 mA·g−1, the first discharge capacity decreased to 110 mAh·g−1 and retained 95% of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density. Foundation item: Supported by the National Natural Science Foundation of China (20071026) Biography: ZHOU Xin-wen (1980-), male, Master, research direction: inorganic material chemistry.  相似文献   

19.
The rate constant for the reaction of OH radicals and hydrogen sulfide (H2S) was studied in different bath gases (including N2, air, O2 and He) by using relative technique at 298 K. The small difference of the measured rate constants between N2 and those with the presence of O2 suggested possible influence of HS self reaction. Further experiments with NOx presence for scavenging HS demonstrated this assumption. The rate constant of (5.48±0.12) ×10–12 cm3 molecule–1 s–1 obtained with 4.09 ×10–4 mol m3 NO presence may be accurate for estimating the atmospheric lifetime of H2S. The results provided circumstantial evidence that the rapid reaction of HS with N2O is suspected.  相似文献   

20.
To promote substantially the performances of red phosphorous(P) anode for lithium and sodium-ion batteries, a simple plasma assisted milling(P-milling) method was used to in-situ synthesize SeP2/C composite. The results showed that the amorphous SeP2/C composite exhibits the excellent lithium and sodium storage performances duo to the small nano-granules size and complete combination of selenium(Se) and phosphorous(P) to generate Se–P alloy phase. It was observed that insid...  相似文献   

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