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Assessing exposure risks for aquatic organisms posed by Tamiflu use under seasonal influenza and pandemic conditions
2014
Chen, Wei-Yu | Lin, Jiarong | Liao, Chung-Min
Environmental pollution by anti-influenza drugs is increasingly recognized as a threat to aquatic environments. However, little is known about empirical data on risk effects posed by environmentally relevant concentrations of anti-influenza drug based on recently published ecotoxicological researches in Taiwan. Here we linked ecotoxicology models with an epidemiological scheme to assess exposure risks of aquatic organisms and environmental hazards posed by antiviral oseltamivir (Tamiflu) use in Taiwan. Built on published bioassays, we used probabilistic risk assessment model to estimate potential threats of environmentally relevant hazards on algae, daphnid, and zerbrafish. We found that Tamiflu use was unlikely to pose a significant chronic environmental risk to daphnia and zebrafish during seasonal influenza. However, the chronic environmental risk posed by Tamiflu use during pandemic was alarming. We conclude that no significant risk to algal growth was found during seasonal influenza and high pandemic Tamiflu use.
显示更多 [+] 显示较少 [-]Growth losses in Swiss forests caused by ozone: Epidemiological data analysis of stem increment of Fagus sylvatica L. and Picea abies Karst
2014
Braun, Sabine | Schindler, Christian | Rihm, Beat
The estimate of growth losses by ozone exposure of forest trees is a significant part in current C sequestration calculations and will also be important in future modeling. It is therefore important to know if the relationship between ozone flux and growth reduction of young trees, used to derive a Critical Level for ozone, is also valid for mature trees. Epidemiological analysis of stem increment data from Fagus sylvatica L. and Picea abies Karst. observed in Swiss forest plots was used to test this hypothesis. The results confirm the validity of the flux-response relationship at least for beech and therefore enable estimating forest growth losses by ozone on a country-wide scale. For Switzerland, these estimates amount to 19.5% growth reduction for deciduous forests, 6.6% for coniferous forests and 11.0% for all forested areas based on annual ozone stomatal uptake during the time period 1991–2011.
显示更多 [+] 显示较少 [-]Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure
2014
Watanabe, Makoto | Hoshika, Yasutomo | Inada, Naoki | Koike, Takayoshi
To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol−1, during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons.
显示更多 [+] 显示较少 [-]On the use of an explicit chemical mechanism to dissect peroxy acetyl nitrate formation
2014
Xue, Likun | Wang, Tao | Wang, Xinfeng | Blake, Donald R. | Gao, Jian | Nie, Wei | Gao, Rui | Gao, Xiaomei | Xu, Zheng | Ding, Aijun | Huang, Yu | Lee, Shuncheng | Chen, Yizhen | Wang, Shulan | Chai, Fahe | Zhang, Qingzhu | Wang, Wenxing
Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role in atmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides (NOx) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of individual precursor species. Here we use an explicit photochemical model – Master Chemical Mechanism (MCM) model – to dissect PAN formation and identify principal precursors, by analyzing measurements made in Beijing in summer 2008. PAN production was sensitive to both NOx and VOCs. Isoprene was the predominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbons dominated at downtown. PAN production was attributable to a relatively small class of compounds including NOx, xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advance understanding of PAN photochemistry to a species level, and provide more relevant recommendations for mitigating photochemical pollution in large cities.
显示更多 [+] 显示较少 [-]Estimating urban roadside emissions with an atmospheric dispersion model based on in-field measurements
2014
Pu, Yichao | Yang, Chao
Urban vehicle emission models have been utilized to calculate pollutant concentrations at both microscopic and macroscopic levels based on vehicle emission rates which few researches have been able to validate. The objective of our research is to estimate urban roadside emissions and calibrate it with in-field measurement data. We calculated the vehicle emissions based on localized emission rates, and used an atmospheric dispersion model to estimate roadside emissions. A non-linear regression model was applied to calibrate the localized emission rates using in-field measurement data. With the calibrated emission rates, emissions on urban roadside can be estimated with a high accuracy.
显示更多 [+] 显示较少 [-]Passive sampling of perfluorinated chemicals in water: In-situ calibration
2014
Kaserzon, Sarit L. | Hawker, Darryl W. | Booij, Kees | O'Brien, Dominique S. | Kennedy, Karen | Vermeirssen, Etiënne L.M. | Mueller, Jochen F.
Perfluorinated chemicals (PFCs) have been recognised as environmental pollutants that require monitoring. A modified polar organic chemical integrative sampler (POCIS) is able to quantify aqueous PFCs. However, with varying external water velocity, PFC sampling rates (Rs) may change, affecting accuracy of derived water concentrations. To facilitate field deployment of this sampler, two methods of in-situ calibration were investigated: performance reference compounds (PRCs) and passive flow monitors (PFMs). Increased Rs's (by factors of 1.2–1.9) with PFM loss rate (g d−1) were observed for some PFCs. Results indicate PFMs can be used to correct PFC specific Rs's for more reliable estimates of environmental concentrations with a precision of about 0.01 L d−1. Empirical models presented provide an improved means for aquatic monitoring of PFCs. The PRC approach was unsuccessful, confirming concern as to its applicability with such samplers.
显示更多 [+] 显示较少 [-]Explaining PAH desorption from sediments using Rock Eval analysis
2014
Poot, Anton | Jonker, M.T.O. | Gillissen, Frits | Koelmans, Albert A.
Here, we provide Rock Eval and black carbon (BC) characteristics and polycyclic aromatic hydrocarbon (PAH) distribution coefficients (KD) for sediments from the Danube, Elbe, Ebro, and Meuse river basins. PAH desorption kinetic parameters were determined using sequential Tenax extractions. We show that residual carbon (RC) from Rock Eval analysis is an adequate predictor of fast, slow, and very slow desorbing fractions of 4-ring PAHs. RC correlated better than BC, the latter constituting only 7% of RC. A dual domain sorption model was statistically superior to a single domain model in explaining KD for low molecular weight PAHs, whereas the opposite was observed for high molecular weight PAHs. Because particularly the 4-ring PAHs are bioavailable and relevant from a risk assessment perspective and because their fast desorbing fractions correlate best with RC, we recommend RC as a relevant characteristic for river sediments.
显示更多 [+] 显示较少 [-]Dose-response relationship between polycyclic aromatic hydrocarbon metabolites and risk of diabetes in the general Chinese population
2014
Yang, Liangle | Zhou, Yun | Sun, Huizhen | Lai, Hanpeng | Liu, Chuanyao | Yan, Kai | Yuan, Jing | Wu, Tangchun | Chen, Weihong | Zhang, Xiaomin
The incidence of diabetes is increasing rapidly in Chinese population, and it has been postulated that environmental factors may play a role in the etiology of diabetes. Therefore, we aimed to investigate the association between PAHs exposure and risk of diabetes in a community-based population of 2824 participants with completed questionnaires, measurements of biochemical indices, and urinary PAHs metabolites. We found that elevated urinary PAHs metabolites were associated, in a dose-dependent manner, with increased risk of diabetes. Particularly, these associations were more evident in subjects who were female, less than 55 years old, nonsmokers, and normal weight. In addition, there was a modest improvement in diabetes discrimination of prediction models when incorporating certain PAHs metabolites into conventional risk factors (CRF). Overall, our data suggested that there may be a dose-dependent relationship between PAHs metabolites and risk of diabetes among general Chinese population.
显示更多 [+] 显示较少 [-]Synergistic sub-lethal effects of a biocide mixture on the springtail Folsomia fimetaria
2014
Schnug, Lisbeth | Leinaas, Hans Petter | Jensen, John
The toxicity of three biocides, esfenvalerate, picoxystrobin and triclosan, on adult survival and recruitment of juveniles was studied in the springtail Folsomia fimetaria, both in single and mixture experiments. Recruitment of juveniles was more sensitive to biocide exposure than adult survival. The concepts of concentration addition and independent action returned almost identical toxicity predictions, though both models failed to predict the observed toxicity due to synergistic deviations at high exposure concentrations. A comparison with a similar study on earthworms showed that response-patterns were species-specific. Consequently, there is no single reference concept which is applicable for all species of one ecosystem, which in turn questions the usefulness of such mixture prediction concepts in ecological risk assessment.
显示更多 [+] 显示较少 [-]Acute effects of air pollution on asthma hospitalization in Shanghai, China
2014
Cai, Jing | Zhao, Ang | Zhao, Jinzhuo | Chen, Renjie | Wang, Weibing | Ha, Sandie | Xu, Xiaohui | Kan, Haidong
Air pollution has been accepted as an important contributor to asthma development and exacerbation. However, the evidence is limited in China. In this study, we investigated the acute effect of air pollution on asthma hospitalization in Shanghai, China. We applied over-dispersed generalized additive model adjusted for weather conditions, day of the week, long-term and seasonal trends. An interquartile range increase in the moving average concentrations of PM10, SO2, NO2 and BC on the concurrent day and previous day corresponded to 1.82%, 6.41%, 8.26% and 6.62% increase of asthmatic hospitalization, respectively. The effects of SO2 and NO2 were robust after adjustment for PM10. The associations appeared to be more evident in the cool season than in the warm season. Our results contribute to the limited data in the scientific literature on acute effects of air pollution on asthma in high exposure settings, which are typical in developing countries.
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