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Reprint of On the link between biomagnetic monitoring and leaf-deposited dust load of urban trees: Relationships and spatial variability of different particle size fractions Full text
2014
Hofman, Jelle | Wuyts, Karen | Van Wittenberghe, Shari | Brackx, Melanka | Samson, Roeland
Biomagnetic monitoring of urban tree leaves has proven to be a good estimator of ambient particulate matter. We evaluated its relevancy by determining leaf area normalised weight (mg m−2) and SIRM (A) of leaf-deposited particles within three different size fractions (>10 μm, 3–10 μm and 0.2–3 μm) and the SIRM of the leaf-encapsulated particles. Results showed that throughout the in-leaf season, the trees accumulated on average 747 mg m−2 of dust on their leaves, of which 74 mg m−2 was within the 0.2–10 μm (∼PM10) size range and 40 mg m−2 within the 0.2–3 μm (∼PM3) size range. A significant correlation between the SIRM and weight of the surface-deposited particles confirms the potential of biomagnetic monitoring as a proxy for the amount of leaf-deposited particles. Spatial variation of both SIRM and weight throughout the street canyon suggests traffic and wind as key factors for respectively the source and distribution of urban particulates.
Show more [+] Less [-]Release and environmental impact of silver nanoparticles and conventional organic biocides from coated wooden façades Full text
2014
Künniger, Tina | Gerecke, Andreas C. | Ulrich, Andrea | Huch, Anja | Vonbank, Roger | Heeb, Markus | Wichser, Adrian | Haag, Regula | Kunz, Petra | Faller, Markus
This study represents for the first time a comprehensive assessment of functionality and environmental impacts of metallic silver nanoparticles (Ag-NP) compared to conventional organic biocides. Four different transparent, hydrophobic coatings of wooden outdoor façades were tested during one year outdoor weathering.The total silver release from products with Ag-NP was proportional to the overall erosion of the coating. The results indicate that the Ag-NPs are likely transformed to silver complexes, which are considerably less toxic than ionic silver. The protective effect of the silver containing coatings against mold, blue stain and algae was insufficient, even in immaculate and non-weathered conditions. The release of organic biocides from conventional coatings was dependent on the weather conditions, the type of biocide and the use in the base or top coat. The conventional coating showed a good overall performance free from mold, blue stain and algae until the end of the test period.
Show more [+] Less [-]Homologue specific analysis of a polyether trisiloxane surfactant in German surface waters and study on its hydrolysis Full text
2014
The occurrence of a polyether trisiloxane surfactant in the ng L−1 range in German surface waters is reported for the first time. The studied surfactant does not ubiquitously occur in the aquatic environment but can reach surface waters on a local scale. As a first step towards the understanding of the environmental fate, the hydrolysis was studied according to the OECD guideline 111. It confirmed that the trisiloxane surfactant is sensitive to hydrolysis and that the hydrolysis rate strongly depends on the pH and the temperature. If one takes only into account the hydrolysis, the trisiloxane surfactant could persist several weeks in river water (the half-life in water is approximately 50 days at pH 7, 25 °C, and an initial concentration of 2 mg L−1). A degradation product, more polar than the initial trisiloxane surfactant, was identified by high resolution mass spectrometry.
Show more [+] Less [-]Prevalence and sunlight photolysis of controlled and chemotherapeutic drugs in aqueous environments Full text
2014
Lin, Angela Yu-Chen | Lin, Yanjing | Lee, Wan-Ning
This study addresses the occurrences and natural fates of chemotherapeutics and controlled drugs when found together in hospital effluents and surface waters. The results revealed the presence of 11 out of 16 drugs in hospital effluents, and the maximum detected concentrations were at the μg L−1 level in the hospital effluents and the ng L−1 level in surface waters. The highest concentrations corresponded to meperidine, morphine, 5-fluorouracil and cyclophosphamide. The sunlight photolysis of the target compounds was investigated, and the results indicated that morphine and codeine can be significantly attenuated, with half-lives of 0.27 and 2.5 h, respectively, in natural waters. Photolysis can lower the detected environmental concentrations, also lowering the estimated environmental risks of the target drugs to human health. Nevertheless, 5-fluorouracil and codeine were found to have a high risk quotient (RQ), demonstrating the high risks of directly releasing hospital wastewater into the environment.
Show more [+] Less [-]Development of a passive sampler for Zinc(II) in urban pond waters using a polymer inclusion membrane Full text
2014
Almeida, M. Inês G.S. | Chan, Cleopas | Pettigrove, Vincent J. | Cattrall, Robert W. | Kolev, Spas D.
The use of a polymer inclusion membrane (PIM) in a novel passive sampler to measure the time-weighted average concentration of Zn(II) in urban waters is described. The passive sampler consists of a compartment containing an acidic receiving solution, which is separated from the external source solution by a PIM consisting of 40 wt% di-2-(ethylhexyl) phosphoric acid as the extractant, and 60 wt% poly-(vinyl chloride) as the base polymer. Two laboratory passive sampling techniques were tested. One involved immersion of the passive sampler into a source solution (“dip-in” approach) for a predetermined period of time while in the other one the source solution was flown past the membrane of the sampler (“flow-through” approach). The latter approach was found to be more suitable for the calibration of the passive sampler under laboratory conditions. A successful application using the “dip-in” sampling approach in urban waters has been conducted for proof of concept.
Show more [+] Less [-]Environmental externality and inequality in China: Current Status and future choices Full text
2014
Zhao, Xiaoli | Zhang, Sufang | Fan, Chunyang
Along with China's rapid economic growth, the environmental externality in the country is getting more and more serious. China's environmental externality is accompanied by environmental inequality, which presents two characteristics: First, the health loss caused by environmental externality is concentrated in the elderly and children. We take Beijing as an empirical analysis to conclude that children (0–4 years old) are the largest group suffered from respiratory disease; while the seniors are the largest group suffered from cardiovascular disease. Second, China's environmental inequality is mainly caused by the transfer of industries from urban to rural areas/suburbs. The villagers in poor rural areas are the biggest victims. China's environmental inequality is reflected particularly by the phenomenon of “cancer villages” which has existed ever since the end of 1970s. Finally, policy recommendations are provided for reducing China's environmental externality and inequality.
Show more [+] Less [-]Distribution of atmospheric particulate matter (PM) in rural field, rural village and urban areas of northern China Full text
2014
Li, Wei | Wang, Chen | Wang, Hongqijie | Chen, Jiwei | Yuan, Chenyi | Li, Tongchao | Wang, Wentao | Shen, Huizhong | Huang, Ye | Wang, Rong | Wang, Bin | Zhang, Yanyan | Chen, Han | Chen, Yuanchen | Tang, Jianhui | Wang, Xilong | Liu, Junfeng | Coveney, Raymond M. | Tao, Shu
Atmospheric PM10 were measured for 12 months at 18 sites along a 2500 km profile across northern China. Annual mean PM10 concentrations in urban, rural village, and rural field sites were 180 ± 171, 182 ± 154, and 128 ± 89 μg/m3, respectively. The similarities in PM10 concentrations between urban and rural village sites suggest that strong localized emissions and severe contamination in rural residential areas are derived from solid fuels combustion in households. High PM10 concentrations in Wuwei and Taiyuan were caused by either sandstorms or industrial activities. Relatively low PM10 concentrations were observed in coastal areas of Dalian and Yantai. Particulate air pollution was much higher in winter and spring than in summer and fall. Multiple regression analysis indicates that 35% of the total variance can be attributed to sandstorms, precipitation and residential energy consumption. Over 40% of the measurements in both urban and rural village areas exceeded the national ambient air quality standard.
Show more [+] Less [-]Evaluation of effects of long term exposure on lethal toxicity with mammals Full text
2014
Verma, Vibha | Yu, Qiming J. | Connell, D. W.
The relationship between exposure time (LT50) and lethal exposure concentration (LC50) has been evaluated over relatively long exposure times using a novel parameter, Normal Life Expectancy (NLT), as a long term toxicity point. The model equation, ln(LT50) = aLC50ν + b, where a, b and ν are constants, was evaluated by plotting lnLT50 against LC50 using available toxicity data based on inhalation exposure from 7 species of mammals. With each specific toxicant a single consistent relationship was observed for all mammals with ν always <1. Use of NLT as a long term toxicity point provided a valuable limiting point for long exposure times. With organic compounds, the Kow can be used to calculate the model constants a and v where these are unknown. The model can be used to characterise toxicity to specific mammals and then be extended to estimate toxicity at any exposure time with other mammals.
Show more [+] Less [-]Influence of canopy drip on the indicative N, S and δ15N content in moss Hypnum cupressiforme Full text
2014
Skudnik, Mitja | Jeran, Z. (Zvonka) | Batič, Franc | Simoncic, Primoz | Lojen, Sonja | Kastelec, Damijana
Samples of Hypnum cupressiforme were collected at two types of site in forest areas: within the forest stand and within forest openings, and analyzed for N and S concentrations and δ15N. Mosses sampled within forest openings reflect the atmospheric N deposition; however, no influence of throughfall N deposition on the N in the moss that was sampled within the forest stand was found, nor was any influence of S deposition on the S in the moss found. For the N and S concentrations in the mosses sampled within forest openings, the within-site variability was comparable to the between-site variability, and for the δ15N, the within-site variability was lower than the between-site. The results showed that a short distance (<1 m) between the sampling location and the nearest tree canopy increases the N in the moss, and significantly higher values are found in mosses sampled in areas within the forest stand.
Show more [+] Less [-]Spatial and temporal analysis of Air Pollution Index and its timescale-dependent relationship with meteorological factors in Guangzhou, China, 2001–2011 Full text
2014
Li, Li | Qian, Jun | Ou, Chun-Quan | Zhou, Ying-Xue | Guo, Cui | Guo, Yuming
There is an increasing interest in spatial and temporal variation of air pollution and its association with weather conditions. We presented the spatial and temporal variation of Air Pollution Index (API) and examined the associations between API and meteorological factors during 2001–2011 in Guangzhou, China. A Seasonal-Trend Decomposition Procedure Based on Loess (STL) was used to decompose API. Wavelet analyses were performed to examine the relationships between API and several meteorological factors. Air quality has improved since 2005. APIs were highly correlated among five monitoring stations, and there were substantial temporal variations. Timescale-dependent relationships were found between API and a variety of meteorological factors. Temperature, relative humidity, precipitation and wind speed were negatively correlated with API, while diurnal temperature range and atmospheric pressure were positively correlated with API in the annual cycle. Our findings should be taken into account when determining air quality forecasts and pollution control measures.
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