共查询到19条相似文献,搜索用时 171 毫秒
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目的 计算元素从我国土壤经膳食向成年男子全身的转移系数和碱土元素、碱金属元素DF值。方法 依据本系列研究所获我国成年男子膳食元素摄入量更新值和68例尸体全身负荷量,并引用我国土壤背景值,按照UNSCEAR环境转移模式和观察比法分别计算了元素在土壤、膳食和全身三环节间转移系数和DF值。结果 获得了50种元素由土壤经膳食向全身的转移系数,碱土元素(包括Pb)和碱金属元素在这三环节间DF值。结论 这些元素的P23或P234都比P34小得多;P23、P34和P234分别以Hg、Ca和Se最高,而以Ce、In和Y最低;稀土元素的P23和P234都小于碱金属或碱土元素。碱土元素从土壤-膳食-全身的DF都小于1,自钙随原子序的增大或减小,DF值都呈递减趋势,铅DF值在锶和钡之间。碱金属元素铷或铯从土壤向膳食转移DF小于1,而由膳食向全身转移DF大于1。 相似文献
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目的 调查徐州市大气颗粒物中的细颗粒物(PM2.5)中多环芳烃(PAHs)的污染水平并对人群进行健康风险评估。方法 采用大气中流量采样器在徐州市泉山区采集PM2.5样品,用液相色谱法定量分析2016年徐州市PM2.5中16种PAHs的质量浓度,并对人群健康风险进行评估。结果 2016年徐州市大气PM2.5中PAHs月平均总质量浓度(∑16PAHs)范围为0.85~94.8 ng/m3,16种致癌性PAHs的等效致癌浓度(BEQ)范围为0.00011~6.81 ng/m3;儿童、成年男性、成年女性PAHs的致癌超额危险度年平均值分别为1.10×10-6、1.67×10-6、1.59×10-6。结论 徐州市区大气PM2.5中多环芳烃污染较为严重,但致癌风险处于可接受水平。 相似文献
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目的 提出大气放射性气溶胶连续监测大流量空气采样中所遇问题(如滤膜堵塞、滤膜吸水及空气中颗粒物对探测效率的影响)的解决办法。方法 通过对连续监测取得的数据进行分析,通过实验模拟滤膜堵塞情况,并通过实际工作验证。结果 获得具有连续代表性的样品,并且获取到有效监测结果数据的天数占全年天数的比例逐年上升,2003~2006年分别为71%,86%,94%,96%。结论 通过采取综合手段,能够减小不利气候因素对采样连续代表性的影响,获得理想的数据有效率。应通过对探测效率进行修正而减小空气中颗粒物含量对探测效率的影响。 相似文献
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目的 了解宜昌城区霾与非霾天气下PM2.5中元素污染特征,为本地区雾霾天气对人体健康效应的研究以及环保调控措施的制定提供科学依据。 方法 2016年12月-2017年11月利用中流量采样器采集大气中PM2.5,电感耦合等离子体质谱检测铍、铝、铬、锰、镍、砷、硒、镉、锑、汞、铊和铅含量后,对12种元素霾与非霾天气下的差异进行比较。 结果 宜昌市大气中PM2.5质量浓度的年均值为56.4 μg/m3,呈冬季(94.0 μg/m3)>春季(50.6 μg/m3)>秋季(36.6 μg/m3)>夏季(28.1 μg/m3)趋势;12种元素中污染水平最高的是铝(141.2 ng/m3),其次依次是铅(37.8 ng/m3)、锰(25.3 ng/m3)、砷(5.29 ng/m3)等。检测的12种元素占PM2.5质量浓度的0.393%,非霾日(0.555%)高于霾日(0.232%)。 结论 宜昌市大气中PM2.5污染情况较以往有所改善,但砷、铬、铅等金属污染应当予以重视。 相似文献
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目的 探讨环境空气放射性水平及与空气质量的关系。方法 选取2017年9月-12月期间,以SNOW WHITE大流量采样器进行空气样品收集,连续24 h采样,以TBM-3S测量仪对收集的样品滤膜表面进行表面放射性测量,将测得结果分别与空气质量等级、大气中PM2.5、PM10颗粒物浓度进行统计学比较分析。结果 37个大气气溶胶滤膜样品的表面放射性水平为(1.051~2.831)Bq/cm2,平均值为1.802 Bq/cm2;不同空气质量等级间比较大气中放射性水平无显著性差异(P ≥ 0.05),不同颗粒物浓度间比较大气中放射性水平无显著性差异(P ≥ 0.05)。结论 监测期间,空气质量及大气中颗粒物含量的变化,未引起大气中放射性水平的变化,空气质量与大气放射性水平不相关。 相似文献
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稳定性同位素评价藏族青年男子膳食铁的吸收率 总被引:3,自引:1,他引:3
目的用铁的稳定性同位素示踪剂评价藏族青年男子膳食铁的吸收率,为改善该人群膳食铁吸收的提供参考数据。方法于现场进行人体代谢试验,受试者口服稳定性同位素示踪铁剂(浓集57Fe的FeSO4)及稀土元素镝,粪便监测法收集示踪剂排出粪样;用感耦等离子体质谱仪测定粪样57Fe56Fe的比值,分析评价该人群膳食铁的吸收率。结果口服同位素评价藏族青年男子膳食铁的吸收率为13.4%±6.4%;每日示踪剂铁和镝排出呈良好相关性。结论稀土元素镝与未吸收的示踪剂铁在消化道有一致的排出过程,前者的回收率能很好反映粪样收集情况;藏族成年男子膳食铁的吸收较好。 相似文献
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目的:为制定中国健康成年男性左室舒张末期容积参考值的统一标准提供科学依据。方法收集了中国107个单位测定的2311例健康成年男性左室舒张末期容积参考值,运用回归分析、非线性回归和主成分分析3种方法进行比较,选择最优模型,得出其与7项地理环境的关系。结果发现用主成分分析方法得出的模型表达中国健康成年男性左室舒张末期容积参考值与中国地理环境之间的相关关系最优。用主成分分析的方法得出回归方程:=106.43+0.0012867X1+0.0023259X2-0.24617X3-0.18152X4-0.0030320X5+0.13273X6-0.78725X7在该回归方程中,是中国健康成年男性左室舒张末期容积参考值(mL),X1是海拔高度(m),X2是年日照时数(h),X3是年平均气温(℃),X4是年平均相对湿度(%),X5是年降水量(mm),X6是气温年较差(℃),X7是年平均风速(m·s-1)。并通过克里格(Kriging)插值法精确的内插出中国健康成年男性左室舒张末期容积参考值的地理分布图。结论如果知道了中国某地的地理环境,就可用此模型估算该地区中国健康成年男性左室舒张末期容积的参考值,从地理分布图也可得到中国任何地方中国健康成年男性左室舒张末期容积的参考值。 相似文献
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The daily urinary excretion of Th (Th) was estimated in 11 adult German subjects who were not exposed occupationally to thorium and its related compounds. Thirty-one urine samples were collected over 24-h periods on different occasions from these subjects and were analyzed using high resolution sector field inductively coupled plasma mass spectrometry (HR-SF-ICP-MS). Using this instrument a limit of detection of 20 pg L for thorium in the reagent blank was achieved. The median (mean) daily urinary thorium excretion was obtained as 1.0 (1.8) ng. This was in good agreement with the mean value of 1.5 ng Th (6 microBq) reported by another group for German population, but is significantly lower in comparison to the daily excretion range of 3.6 to 105 ng reported from other countries. The expected daily urinary excretion of thorium for the adult German population was also calculated by applying the new ICRP biokinetic model of thorium assuming reference intake values. The expected urinary thorium excretion rate for this age group is about 0.1 ng per day. Even if a small contribution from the inhalation is considered, the calculated value will be much lower than the measured values. The reason for the disagreement appears to be the use of a low gastrointestinal absorption factor (f1) of 5 x 10 in the ICRP model. Based on the present study, a higher f1 factor might be proposed separately for dietary incorporated thorium. 相似文献
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Quantifying the distribution of inhalation exposure in human populations: distribution of minute volumes in adults and children.
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Assessments of inhalation exposure to environmental agents necessitate quantitative estimates of pulmonary ventilation rates. Estimating a range of exposures in a given population requires an understanding of the variability of ventilation rates in the population. Distributions of ventilation rates (Ve) were described based on the results of a large study where Ve were measured while subjects performed a variety of physical tasks. Three distinct ventilation levels were identified using cluster analyses of the mean Ve and then various activities were assigned to the three levels using a k-means procedure. Separate distributions were identified for the three Ve levels for adult males, adult females, and children. The variability of Ve was consistent with a lognormal distribution for all groups. An aggregate daily inhalation rate can be estimated based on the distributions of Ve. 相似文献
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Behavioral factors predicting serum cotinine concentrations of male smokers in a Japanese community. 总被引:1,自引:0,他引:1
T Nakayama T Yokoyama N Yoshiike T Ichimura A Yamamoto H Tanaka 《Journal of epidemiology / Japan Epidemiological Association》1999,9(3):143-145
Cigarette-derived toxic substances are inhaled along with the nicotine that is absorbed to satisfy the smoker's physical demand. Therefore, serum cotinine, a metabolite of nicotine, may be considered to be an indirect marker of absorption of the other toxic substances from smoking. However, few studies have examined factors related to serum cotinine concentrations in natural settings. The authors, therefore, have studied relations among patterns of smoking behavior and serum cotinine concentrations of community residents. Subjects were 60 smoking men living in the town of Yamasaki, Hyogo Prefecture, Japan. Number of daily cigarettes, depth of inhalation, hours from the last cigarette smoked and the total nicotine tolerance score were significantly, while neither nicotine-yields nor butt length of a discarded cigarette was correlated with serum cotinine concentrations. Multiple regression analysis confirmed that depth of inhalation and hours from the last cigarette smoked were independently significant. This finding suggests that attention only to self-reported daily number of cigarettes smoked may not be sufficient to detect smokers who are actually at high risk. Healthcare workers should also pay attention to smokers' patterns of smoking, particularly depth of inhalation. 相似文献
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目的研究简体中文版老年男性症状量表(Chinese version of the Aging Males'Symptoms scale,CN-AMS)应用于国内中老年男性迟发性性腺功能减退时的信度、效度及实际使用效果。方法受访人群包括33岁以下青年男性27人,40岁以上中老年男性81人。要求所有受访志愿者完成AMS量表填写及间隔4周后的复填,以验证CN-AMS量表的有效性。为了验证中老年受访者是否存在雄激素缺乏,在每次填写量表时抽取空腹晨血,检测血清总睾酮(total serum testosterone,TT)、性激素结合球蛋白(sex hormone binding globulin,SHBG)水平,计算出血清游离睾酮(calculated free testosterone,cFT)水平。统计学上采用α信度系数法(Cronbach’s alpha)和重测信度法(test-retest stability)验证CN-AMS量表的信度。重测信度法采用Pearson相关性(Pearson's correlation)分析重测相关系数。采用单项与总和相关效度分析(Pearson's correlation)验证CN-AMS量表的逻辑效度。结果 27位青年男性完成了量表填写及4周后的复填。81位中老年男性中有57人接受了重复抽血,其中46位完成量表复填。CN-AMS量表的Cronbach’sα信度系数和Pearson's correlation系数在青年组为0.86和0.91,老龄组是0.91和0.83,两组人群合并后的数值则是0.94和0.91,显示出很好的效度和内在结构一致性。以cFT 225 pmol/L作为诊断迟发性性腺功能减退(late onset hypogonadism in males,LOH)的血清学阈值。量表的敏感度为81%,特异性为44%。结论研究证明CN-AMS在中国中老年男性LOH筛查中具有良好的适用性,但其特异性并不高,不适合单独用于LOH的诊断。 相似文献
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This study focused on the determination of consumption habits and nutritional composition of ready-to-eat grilled pork from Benin. A face-to-face survey of 372 grilled pork consumers using a semi-structured questionnaire was carried out in the same municipalities where 24 samples of grilled pork were collected for physico-chemical characterisation. Three hundred out of 372 (80.6 %) consumers eating grilled pork at least once per month were selected to estimate the daily intake of protein, lipid and fatty acids. Grilled pork consumption ranged between 0.7 g/day and 342.9 g/day with a median of 28.6 g/day. Protein and lipid contents ranged between 19.5 % and 69.5 % of dry weight and between 27.9 % and 82.1 % of dry weight, respectively. Fatty acid profile showed that linoleic acid was the most abundant omega 6-PUFA (Polyunsaturated fatty acid). The consumption of high quantity of grilled pork (342.9 g/day) enables to cover 25 % (for women) and 31 % (for men) of adult requirement of PUFA (11−22 g/day for women and 14−28 g/day for men). The omega 6 daily intake from high grilled pork consumption contributed to satisfy about 15 % of adult requirement of omega 6 fatty acids for both genders while the omega 3 daily intake from high grilled pork consumption was over 80 % for both genders. 相似文献