Search Results

You are looking at 1 - 10 of 30 items for

  • Author or Editor: Z. Chai x
  • All content x
Clear All Modify Search

Abstract  

In 1999 investigation, the needles of Sabina chinesis L. from 11 hot spot tourist cities extending over China were collected as biomonitors for evaluation of atmospheric elemental differences in those cities. Thirty five elements were determined by instrumental neutron activation analysis (INAA). The experimental data reflected the environmental alteration in the cities that have different geographical position, population burden and industrialized level. Eventually by using the data processed by factor analysis (FA) and subsequent cluster analysis (CA), the cities were grouped into six sorts of the urban atmospheric deposition with corresponding elements.

Restricted access

Abstract  

The concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in placenta, umbilical cord and hair of mothers delivering disabled or normal newborns as well as the compositions of EPOCl in three analyzed matrices were determined by a combination of NAA, gas chromatography and chemical separation. The results indicated that both EOX and EPOX decreased in the order: hair > umbilical cord > placenta. Organochlorines were the major fraction of organohalogens. More than 77% of EPOCl were unidentified. High organohalogens exposure may induce adverse health effects, and hair, as a biomonitor for organohalogens assessment, is more recommendable.

Restricted access

Summary  

Air samples were collected at a downtown site in Beijing from January to July 2004 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOX were increasing in the order of EOCl >> EOBr ~ EOI in both gaseous and particulate phase. EOCl accounted for 75.8-100% and 83.7-100% of EOX in particulate and gaseous phase, respectively, suggesting that EOCl was the major component of the organohalogens in the atmosphere. In the plots of the logarithm of the EOX concentrations versus the reciprocal temperature, their linear relations were observed for EOCl (R = -0.9), for EOBr (R = -0.6) and EOI (R = -0.7) in gaseous phase, which indicated that the concentrations of EOCl, EOBr and EOI in gaseous phase exhibited a strong temperature dependence, i.e., their concentrations increased with increasing of temperature.

Restricted access

Abstract  

The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants.

Restricted access

Abstract  

Intact chloroplasts were isolated from mesophyll protoplasts of Brassia napus. Concentrations of 8 rare earth elements (REEs) in the chloroplasts were determined by instrumental neutron activation analysis (INAA). The results showed that there were trace amounts of REEs in the chloroplasts, which corresponded to 1 atom of REEs per 2000 chlorophyll molecules. About 30% of the total REEs in the leaves are localized in the chloroplasts and the light REEs were enriched with respect to the heavy elements of the series.

Restricted access

Abstract  

In order to study the metabolism of physiological amounts of51Cr (10 μg/100 g of body wt.) intragastrically administered in rats, the activable enriched stable isotope Cr-50 compound Cr2O3 was used as a tracer. The absorption and distribution of51Cr(III) in rats with time were studied. Significant51Cr contents were found in all the organs and tissues of interest. The kidney, liver and bone contain higher amounts of51Cr than others. The fact that specific activities of51Cr are notably high in kidney, bone, spleen and pancreas and decrease gradually with time suggests that there are tighter binding of chromium in these organs. The excretion of51Cr at various time intervals was also studied. Almost totally intragastrically administered dose was excreted in the feces. The increased urinary excretion of51Cr with time indicates that the urine-chromium is the metabolic derivative of organism. In view of the tissues distribution and excretion, it can be concluded that no more that 1% of the dose was absorbed from the gastrointestinal tract.

Restricted access

Abstract  

To effectively extract organohalogens from human hair, two factors, the extracting time and hair length on the extraction efficiency of organohalogens were studied by neutron activation analysis (NAA) and gas chromatograph-electron capture detector (GC-ECD), respectively. Furthermore, the concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in hair samples from angioma and control babies were also measured by the established method. The results indicated that the optimal Soxhlet-extraction time for EOX and EPOX in hair was from 8 to 11 hours, and the extraction efficiencies for organochlorine pesticides in hair were in the order of powder >2 mm>5 mm. Also, the mean levels of EOC1 and EPOC1 in hair of the angioma babies were significantly higher than those in the control babies (P EOC1<0.01; P EPOC1<0.05), which implied the possible relationship between the environmental pollution and angioma.

Restricted access

Abstract  

The content of chromium in the DNA, RNA and protein fractions separated from chromium-rich and normal brewer's yeast was determined by neutron activation analysis (NAA). Our results show that the extracted relative amounts and concentrations of DNA, RNA and proteins have no significant difference for two types of yeast, but the chromium content in DNA, RNA and proteins fractions extracted from the chromium-rich yeast are substantially higher than those from the normal. In addition, the concentration of chromium in DNA is much higher than that in RNA and proteins. It is evident that the inorganic chromium compounds can enter the yeast cell during the yeast cultivation in the chromium-containing culture medium and are converted into organic chromium species, which are combined with DNA, RNA and proteins.

Restricted access

Abstract  

Chromium speciation was investigated in the liver cytosol, serum and urine of normal and diabetic rats after a single intravenous injection of enriched stable isotope 50Cr tracer solution. Sephadex G-25 gel chromatography combined with instrumental neutron activation analysis was used to isolate and characterize protein-bound chromium in the above materials. The results indicate that Cr is mainly combined with a high-molecular-weight protein either in liver cytosol or serum. A low-molecular-weight, Cr-containing compound (LMWCr) was found in all the observed liver, serum and urine samples of both normal and diabetic rats. Chromium is excreted chiefly as LMWCr in urine.

Restricted access

Abstract  

Cyclic neutron activation analysis method was conducted for determination of Se in food samples. High accuracy and good precision were proved by analyzing certified reference materials (CRMs) of chicken (GBW10018), rice (GBW10010) and cabbage (GBW10014). The detection limits for the three CRMs reached 0.16, 0.66 and 1.2 ng after 6 cycles at the 161.9 keV γ-peak from 77mSe, under a neutron flux of 9.0 × 1011 n cm−2 s−1 and the conditions of 30 s irradiation, 2 s decay, 30 s counting and 2 s waiting, significantly lower than those of conventional neutron activation analysis without any cycles, which were 0.94, 3.6 and 4.3 ng, respectively.

Restricted access