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1.
BackgroundStudies on the association of maternal exposure to polychlorinated dibenzo- p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease. ObjectiveThe Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight. MethodsBlood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non- ortho PCBs. ResultsTotal PCDD TEQ (adjusted beta = − 161.9 g; 95% CI, −265.3 to − 58.6), total PCDF TEQ (adjusted beta = − 105.9 g; 95% CI, −179.5 to − 32.2), and total non- ortho PCBs (adjusted beta = − 178.4 g; 95% CI, −318.3 to − 38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ, total PCDF TEQ, and total non- ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF. ConclusionIn the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures. 相似文献
2.
BackgroundSeveral studies have found that living near major roadways is associated with an increase in respiratory illness but few studies have measured the volume and type of traffic. ObjectiveWe investigated the relation between traffic volume and respiratory health of 2328 children 9 to 11 years old in the city of Windsor, Canada. MethodsWe identified the roadways within a 200 meter radius of the child's neighborhood using the latitude and longitude of the residential postal code. Traffic exposure was defined as the sum of the annual volume of vehicles on all of these roadways. Volume was calculated using sensors to detect passing vehicles (simple traffic counts), and by counts and direction of traffic at intersections (turning movement counts). Ventilatory lung function was measured by spirometry and airway inflammation by exhaled nitric oxide (eNO). ResultsThe odds ratio between an interquartile increase in truck turning movement counts and chest congestion was 1.20 (1.06-1.35). The percentage of predicted FVC declined 0.68%, (95% CI 1.32, 0.03) for an interquartile increase in simple traffic counts (33,787 vehicles daily). Among those with self-reported asthma, effect sizes were larger. Percentage predicted FEV 1 declined 1.84% (95% CI 0.07, 3.61) associated with an interquartile range increase in turning movement counts. No statistically significant change was detected between traffic measures and exhaled nitric oxide. ConclusionsOur findings provide further support for the hypothesis that neighborhood exposure to traffic-related air pollution increases respiratory symptoms and reduces ventilatory function in children, especially those with self-reported asthma. 相似文献
3.
Methyl tert-butyl ether (MTBE) and benzene are added to gasoline to improve the combustion process and are found in the urban environment as a consequence of vehicular traffic. Herein we evaluate urinary MTBE (MTBE-U) and benzene (BEN-U) as biomarkers of exposure to urban traffic. Milan urban policemen (130 total) were investigated in May, July, October, and December for a total of 171 work shifts. Personal exposure to airborne benzene and carbon monoxide (CO), and atmospheric data, were measured during the work shift, while personal characteristics were collected by a questionnaire. A time/activity diary was completed by each subject during the work shift. Spot urine samples were obtained for the determination of MTBE-U and BEN-U. Median personal exposure to CO and airborne benzene were 3.3 mg/m(3) and 9.6 μg/m(3), respectively; median urinary levels in end-of-shift (ES) samples were 147 ng/L (MTBE-U) and 207 ng/L (BEN-U). The time spent on traffic duty at crossing was about 40% of work time. Multiple linear regression models, taking into account within-subject correlations, were applied to investigate the role of urban pollution, atmospheric conditions, job variables and personal characteristics on the level of biomarkers. MTBE-U was influenced by the month of sampling and positively correlated to the time spent in traffic guarding, CO exposure and atmospheric pressure, while negatively correlated to wind speed (R(2) for total model 0.63, P<0.001). BEN-U was influenced by the month and smoking habit, and positively correlated to urinary creatinine; moreover, an interaction between CO and smoking was found (R(2)=0.62, P<0.001). These results suggest that MTBE-U is a reliable marker for assessing urban traffic exposure, while BEN-U is determined mainly by personal characteristics. 相似文献
4.
A total of 27 per- and polyfluorinated compounds (PFCs) were determined in both house dust (n = 10) and indoor air (n = 10) from selected homes in Catalonia, Spain. Concentrations were found to be similar or lower than those previously reported for household microenvironments in other countries. Ten PFCs were detected in all house dust samples. The highest mean concentrations corresponded to perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA), 10.7 ng/g (median: 1.5 ng/g) and 10.4 ng/g (median: 5.4 ng/g), respectively, while the 8:2 fluorotelomer alcohol (FTOH) was the dominating neutral PFC at a concentration of 0.41 ng/g (median: 0.35 ng/g). The indoor air was dominated by the FTOHs, especially the 8:2 FTOH at a mean (median) concentration of 51 pg/m 3 (median: 42 pg/m 3). A limited number of ionic PFCs were also detected in the indoor air samples. Daily intakes of PFCs were estimated for average and worst case scenarios of human exposure from indoor sources. For toddlers, this resulted in average intakes of ∑ ionic PFCs of 4.9 ng/day (0.33 ng/kg bw/day for a 15 kg toddlers) and ∑ neutral PFCs of 0.072 ng/day (0.005 ng/kg bw/day) from house dust. For adults, the average daily intakes of dust were 3.6 and 0.053 ng/day (0.05 and 0.001 ng/kg bw/day for a 70 kg adult) for ∑ ionic and ∑ neutral PFCs, respectively. The average daily inhalation of ∑ neutral PFCs was estimated to be 0.9 and 1.3 ng/day (0.06 and 0.02 ng/kg bw/day) for toddlers and adults, respectively. For PFOS, the main ionic PFC detected in indoor air samples, the median intakes (based on those samples where PFOS was detected), resulted in indoor exposures of 0.06 and 0.11 ng/day (0.004 and 0.002 ng/kg bw/day) for toddlers and adults, respectively. Based on previous studies on dietary intake and drinking water consumption, both house dust and indoor air contribute significantly less to PFC exposure within this population. 相似文献
5.
Per- and poly-fluorinated compounds (PFCs), which include perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) and various precursors, are used in a wide variety of industrial, commercial and domestic products. This includes aqueous film forming foam (AFFF), which is used by military and commercial airports as fire suppressants. In a preliminary assessment prior to this study, very high concentrations (> 1 ppm wet weight) of the PFSA, perfluorooctane sulfonate (PFOS), were discovered in the plasma of snapping turtles ( Chelydra serpentina) collected in 2008 from Lake Niapenco in southern Ontario, Canada. We presently report on a suite of C 6 to C 15 PFCAs, C 4, C 6, C 8 and C 10 PFSAs, several PFC precursors (e.g. perfluorooctane sulfonamide, PFOSA), and a cyclic perfluorinated acid used in aircraft hydraulic fluid, perfluoroethylcyclohexane sulfonate (PFECHS) in surface water from the Welland River and Lake Niapenco, downstream of the John C. Munro International Airport, Hamilton, Ontario, Canada. Amphipods, shrimp, and water were sampled from the Welland River and Lake Niapenco, as well as local references. The same suite of PFCs in turtle plasma from Lake Niapenco was compared to those from other southern Ontario sites. PFOS dominated the sum PFCs in all substrates (e.g., > 99% in plasma of turtles downstream the Hamilton Airport, and 72.1 to 94.1% at all other sites). PFOS averaged 2223 (± 247.1 SE) ng/g in turtle plasma from Lake Niapenco, and ranged from 9.0 to 171.4 elsewhere. Mean PFOS in amphipods and in water were 518.1 (± 83.8) ng/g and 130.3 (± 43.6) ng/L downstream of the airport, and 19.1 (± 2.7) ng/g and 6.8 (± 0.5) ng/L at reference sites, respectively. Concentrations of selected PFCs declined with distance downstream from the airport. Although there was no known spill event or publicly reported use of AFFF associated with a fire event at the Hamilton airport, the airport is a likely major source of PFC contamination in the Welland River. 相似文献
6.
The Syabru-Bensi hydrothermal zone, Langtang region (Nepal), is characterized by high radon-222 and CO 2 discharge. Seasonal variations of gas fluxes were studied on a reference transect in a newly discovered gas discharge zone. Radon-222 and CO 2 fluxes were measured with the accumulation chamber technique, coupled with the scintillation flask method for radon. In the reference transect, fluxes reach exceptional mean values, as high as 8700 ± 1500 g m −2 d −1 for CO 2 and 3400 ± 100 × 10 −3 Bq m −2 s −1 for radon. Gases fluxes were measured in September 2007 during the monsoon and during the dry winter season, in December 2007 to January 2008 and in December 2008 to January 2009. Contrary to expectations, radon and its carrier gas fluxes were similar during both seasons. The integrated flux along this transect was approximately the same for radon, with a small increase of 11 ± 4% during the wet season, whereas it was reduced by 38 ± 5% during the monsoon for CO 2. In order to account for the persistence of the high gas emissions during monsoon, watering experiments have been performed at selected radon measurement points. After watering, radon flux decreased within 5 min by a factor of 2–7 depending on the point. Subsequently, it returned to its original value, firstly, by an initial partial recovery within 3–4 h, followed by a slow relaxation, lasting around 10 h and possibly superimposed by diurnal variations. Monsoon, in this part of the Himalayas, proceeds generally by brutal rainfall events separated by two- or three-day lapses. Thus, the recovery ability shown in the watering experiments accounts for the observed long-term persistence of gas discharge. This persistence is an important asset for long-term monitoring, for example to study possible temporal variations associated with stress accumulation and release. 相似文献
7.
The vertical distribution of 137Cs activity in peat soil profiles and 137Cs activity concentration in plants of various species was studied in samples collected at two sites on a raised bog in central Sweden. One site (open bog) was in an area with no trees and only a few sparsely growing plant species, while the other (low pine) was less than 100 m from the open bog site and had slowly growing Scots pine, a field layer dominated by some ericaceous plants and ground well-covered by plants. The plant samples were collected in 2004–2007 and were compared with samples collected in 1989 from the same open bog and low pine sites. Ground deposition of 137Cs in 2005 was similar at both sites, 23?000 Bq m −2. In the open bog peat profile it seems to be an upward transport of caesium since a clear peak of 137Cs activity was found in the uppermost 1–4 cm of Sphagnum layers, whereas at the low pine site 137Cs was mainly found in deeper (10–12 cm) layers. The migration rate was 0.57 cm yr −1 at the open bog site and the migration centre of 137Cs was at a depth of 10.7, while the rate at the low pine site was 0.78 cm yr −1 and the migration centre was at 14.9 cm. Heather ( Calluna vulgaris) was the plant species with the highest 137Cs activity concentrations at both sites, 43.5 k Bq −1 DM in 1989 decreasing to 20.4 in 2004–2007 on open bog and 22.3 k Bq kg −1 DM in 1989 decreasing to 11.2 k Bq −1 DM by the period 2004–2007 on the low pine site. 137Cs transfer factors in plants varied between 0.88 and 1.35 on the open bog and between 0.48 and 0.69 m 2 kg −1 DM at the low pine site. 相似文献
8.
A shallow-land radioactive waste repository operated in boggy forest environment from 1963 to 1989. During the operation period, a considerable amount of technogenic radionuclides, in solidified state, was disposed into the vault established in the geological structure at the depth of up to 3 m. Environmental monitoring activities started after the closure of the repository in 1989. Recent investigations revealed transfer of radiocarbon and plutonium to the groundwater in the prevailing flow direction. Activity concentration of 239,240Pu in non-filtered fraction of the groundwater from observation well no. 4 determined by alpha-spectrometry was 6.4 × 10 −5 Bq l −1 in 2005, and 3.2 × 10 −4 Bq l −1 in 2006. Further analysis of colloid-facilitated transport of plutonium is planned. Variation of 14C activity concentration in the same well was monitored in 2006. It varied from 0.2 ± 0.1 Bq l −1 in October to 2.8 ± 0.6 Bq l −1 in June and July. Results imply further research into radiocarbon transfer to atmosphere and selected plant species. 相似文献
9.
Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of 238U and 232Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of 226Ra, 228Ra, and 40K were determined by gamma-ray spectrum. We found the concentrations of 238U series, 232Th series, and 40K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 × 10 −2 Sv y −1, which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 × 10 −4 Sv y −1, which was lower than intervention exemption levels (1.0 × 10 −3 Sv y −1) given in International Commission of Radiological Protection (ICRP) Publication 82. 相似文献
10.
Long-term exposure to radon increases the risk of developing lung cancer. There is considerable public concern about radon exhalation from building materials and the contribution to indoor radon levels. To address this concern, radon exhalation rates were determined for 53 different samples of drywall, tile and granite available on the Canadian market for interior home decoration. The radon exhalation rates ranged from non-detectable to 312 Bq m −2 d −1. Slate tiles and granite slabs had relatively higher radon exhalation rates than other decorative materials, such as ceramic or porcelain tiles. The average radon exhalation rates were 30 Bq m −2 d −1 for slate tiles and 42 Bq m −2 d −1 for granite slabs of various types and origins. Analysis showed that even if an entire floor was covered with a material having a radon exhalation rate of 300 Bq m −2 d −1, it would contribute only 18 Bq m −3 to a tightly sealed house with an air exchange rate of 0.3 per hour. Generally speaking, building materials used in home decoration make no significant contribution to indoor radon for a house with adequate air exchange. 相似文献
11.
Bиccлoвaнияx вoэмocy;жнocтeф пpимeн eния мeтoдoв coвaдeниф дффeктив нoгo cхeтa иэиuхaтeлeф пoхитpoнoв в б oльщиx oбpaэцax, pнpимeня жидкocт ныф cцинтлляциoнныф cхeтхик 4π для вceгo, cocтoяшиф иэ 2-x дeтeктocy;pныx кaмep 2π. Пpeждe вceгo иэuхaлocв oбpaэoвaниe фoн a, кaк oтвeтнaя peaция в мeтoдe co coвпaдeниф. B peэuлвтaтe импuлвcoв coвпaдeни ф в oбoиx дeтeктopныx кaмepax нaблю энaхитeлвныф uхacтoк фoнa. Иэuхaлacvcy; пoдaвлeни я фoнa пuтa cхeтa пueтa cхeтa aнт иcoвпaдeнeниф, нo этoт мeтoд нe oкaэaлcя uля uлu oхыхныx гaммa-иэлucy;хaтaeлeф. oднaк o, в cлнaяx, кoгпa в oбpaэцax coдepж aлиcв тaкиe иэлuхaтeли пoэитpoнoв, кaк 22Na и 58 co, фoн мoжнo былo энaхитeлвнo пoд aвитв и cхeтнuю cтaтиcтикu нa нa мнoгo юл юхшитв пpимeняя пpимeняя cпoco бы ы coвпaдeниф. Этoт мeтoд нe тoдвкo uмeнвщaeт фoн, нo тaкиe мoнoгaмм-иэлuхaтeли, кaк 137Cs 40К. Taким oбким oбpaэoм, этoт мeт oд нaпpaшивaeтcя caм coбoф для иэ peния иэлuхaтeлeф пoэитpoнoв в хeлoвeкe, гдe 137Cs 40К п pиcuтcтвuют, кaк интepфиpuюшиф фoн:. ZusammenfassungEin 4π-Flüssigkeits-“Ganzkörper”-Szintillationszähler, bestehend aus 2π-Detektrortanks wurde dazu verwendet, die mögliche Anwendung von Koinzidenzarbeitsweisen zur wirksamen Zählung von Positronenemittern in grossen Proben zu studieren. Zunächst wurde die Hintergrundemp-findlichkeit für die Koinzidenzform untersucht. Man beobachtete, dass ein ansehnlicher Teil des Hintergrundes von Impulsen in der Koinzidenz in beiden Detektortanks herrührte. Die Möglichkeit einer Unterdrückung des Hintergrundes durch Antikoinzidenzzählung wurde erforscht, aber dies stellte sich als unbrauchbar für eine Verbesserung der Zählstatistik zum Zählen gewöhnlicher Gammaemitter heraus. Wenn die Proben jedoch Positronenemitter wie 22Na and 58Co enthalten, so könnte der Hintergrund weitgehend unterdrückt und die Zählstatistik beträchtlich verbessert werden, wenn man Koinzidenzzählverfahren anwendet. Das Verfahren verminderte nicht nur den Hintergrund, sondern es diskriminierte auch gegenüber solchen Monogammaemittern wie 137Cs und 40K. Das Verfahren eignet sich somit zur Messung von Positronenemittern im Menschen, wo 137Cs und 40K als “Störhintergrund” zugegen sind. PDF (473 K)
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