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Trace element concentrations from lichen transplants in Pretoria, South Africa
2011
Olowoyo, Joshua Oluwole | van Heerden, E. | Fischer, J. L.
Purpose The purpose of this study was to assess the level and possible sources of trace elements in Tshwane metropolis using transplanted lichen thallus of Parmelia sulcata with a view to evaluating the ability of this lichen species to monitor air pollutants from a perceived polluted environment. Methods Samples of the lichen thalli were transplanted into ten different sites and covered with a net. Samples were exposed for 3 months. Concentrations of ten trace elements were determined with the use of inductively coupled plasma mass spectrometry. Results A significant difference was observed in the values of elemental concentration in lichen from unpolluted area and those transplanted to all the sites (p < 0.01). Variations in values of trace elements recorded in lichen transplant from different sites were also statistically significant (p < 0.01). The high traffic sites showed significantly higher elemental concentrations, particularly for Pb, Zn, and Cu than the industrial and residential areas (p < 0.05). Conclusion Trends in the trace element values from different sites suggested that the elements might have come from anthropogenic sources.
显示更多 [+] 显示较少 [-]Trace analysis of persistent toxic substances in the main stream of Jiangsu section of the Yangtze River, China
2011
He, Huan | Hu, Guan-jiu | Sun, Cheng | Chen, Su-lan | Yang, Ming-na | Li, Juan | Zhao, Yong | Wang, Hui
Background, aim, and scope The Jiangsu section of the Yangtze River is the downstream of the whole river, serving as an important drinking water source. Persistent toxic substances (PTS), from the industries such as automobile, textile, chemical, and electronic production, are not listed in the National Standard yet and not monitored and controlled. However, pollution of PTS can threaten the environment and human health. In order to understand the pollution status of the PTS contamination and recommend future rationalization of countermeasure, the PTS including organochlorine pesticides (OCPs), polyaromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and phthalates (PAEs) were investigated. Materials and methods Samples were collected at 15 sites from five main stream sections of the Yangtze River in Jiangsu Province. PTS were extracted using solid phase extract method. The analysis of OCPs, PCBs was performed using GC/ECD and PAHs, PAEs was performed by GC/MS. Results and discussions The method detection limits are low and the recoveries are from 58.1% to 110.3%. The total concentrations of OCPs, PCBs, PAHs, and PAEs were 0.27∼2.15 ng l⁻¹, <0.21∼44.4 ng l⁻¹, 0.012∼3.576 μg l⁻¹ and 0.178∼1.474 μg l⁻¹, respectively. γ-HCH, PCB28, PCB101, phenanthrene, anthracene, di-n-butyl phthalate, diethyl phthalate, and di-(2-ethylhexyl) phthalate are the major detected PTS. The concentration of most of the PTS was below the environmental quality standards for surface water of China. Conclusions The pollution status of OCPs, PCBs, PAHs, and PAEs were analyzed. PTS contamination levels of the five main stream sections were relatively low.
显示更多 [+] 显示较少 [-]An approach to determining potential surrogates for analyzing ecological patterns of planktonic ciliate communities in marine ecosystems
2011
Xu, Henglong | Jiang, Yong | Zhang, Wei | Zhu, Mingzhuang | Al-Rasheid, Khaled A. S.
INTRODUCTION: In order to identify a potential surrogate of planktonic ciliate communities for marine bioassessments and evaluating biological conservations, the different taxonomic/numerical resolutions and taxa as surrogates were studied in Jiaozhou Bay, northern China during a 1-year cycle (June 2007–May 2008). MATERIALS AND METHODS: Samples were collected biweekly from a depth of 1 m at each of five sites. A range of physicochemical parameters were also measured in order to determine water quality. RESULTS: The genus- and family-level resolutions maintained sufficient information to evaluate the ecological patterns of the ciliate communities in response to environmental status. The non-loricate oligotrichous ciliate assemblages in both abundance and occurrence may be used as a surrogate of planktonic ciliate communities. Heavy data transformations were an optimal strategy for the species level of planktonic ciliates, while mild data transformations were for the higher. The ordination patterns based on species biomass, occurrence, and biomass/abundance ratio matrices were significantly consistent with that of species abundance data. CONCLUSION: The results suggest that the use of simplifications at both taxonomic and numerical resolutions are time-efficient and would allow improving sampling strategies of large spatial/temporal scale monitoring programs and biological conservation researches in the marine ecosystem with a relative paucity of scientists.
显示更多 [+] 显示较少 [-]Chlorpyrifos degradation by the cyanobacterium Synechocystis sp. strain PUPCCC 64
2011
Singh, D. P. | Khattar, J. I. S. | Nadda, J. | Singh, Y. | Garg, A. | Kaura, Ainna. | Gulati, A.
BACKGROUND, AIM, AND SCOPE: Indiscriminate use of insecticides leads to environmental problems and poses a great threat to beneficial microorganisms. The aim of the present work was to study chlorpyrifos degradation by a rice field cyanobacterium Synechocystis sp. strain PUPCCC 64 so that the organism is able to reduce insecticide pollution in situ. MATERIAL AND METHODS: The unicellular cyanobacterium isolated and purified from a rice field was identified by partial 16S rRNA gene sequence as Synechocystis sp. strain PUPCCC 64. Tolerance limit of the organism was determined by studying its growth in graded concentrations (2.5–20 mg/L) of chlorpyrifos. Chlorpyrifos removal was studied by its depletion from the insecticide supplemented growth medium, and its biodegradation products were identified in the cell extract, biomass wash, and growth medium. RESULTS AND DISCUSSION: The organism tolerated chlorpyrifos up to 15 mg/L. Major fraction of chlorpyrifos was removed by the organism during the first day followed by slow uptake. Biomass, pH, and temperature influenced the insecticide removal and the organism exhibited maximum chlorpyrifos removal at 100 mg protein/L biomass, pH 7.0, and 30°C. The cyanobacterium metabolized chlorpyrifos producing a number of degradation products as evidenced by GC-MS chromatogram. One of the degradation products was identified as 3,5,6-trichloro-2-pyridinol. CONCLUSION AND RECOMMENDATIONS: Present study reports the biodegradation of chlorpyrifos by Synechocystis sp. Biodegradation of the insecticide by the cyanobacterium is significant as it can be biologically removed from the environment. The cyanobacterium may be used for bioremediation of chlorpyrifos-contaminated soils.
显示更多 [+] 显示较少 [-]Pharmaceuticals in the environment: an educational perspective
2011
PURPOSE: Pharmaceuticals are an integral part of a dignified life. However, a lack of degradability and threats to the welfare of living beings cause concern due to their emission into the environment. There is also a lack of knowledge about cause and consequence. Therefore, we intend to contribute to the development of educational programmes which should increasingly include the topic ‘pharmaceuticals in the environment’. METHODS: Considering the current literature, we developed a corresponding series of worksheets (Online Resource) and sample solutions on an introductory level and integrated them into our curriculum. RESULTS: The material compiled for the worksheets was arranged in a logical order and considers several subtopics. The worksheets aim to support the examination of related aspects such as environmental effects, emissions, wastewater treatment plants, degradation, degradation by-products, advanced oxidation processes, hydraulic retention times, half-life times, biosolids, exposition pathways, precautionary principle, classification schemes for pharmaceuticals and, related to the structure–activity relationship, the design for degradability. The students managed to work on the tasks in an appropriate manner and received a good overview of the occurrence and fate of pharmaceuticals in the environment. CONCLUSIONS: Tasks that were presented to students regarding the topic ‘pharmaceuticals in the environment’ contributed to a better understanding of the possible risks of medical care on an introductory level. The tasks have been incorporated into a logic series of worksheets (Online Resource) with sample solutions available. Alternatively, the material would be appropriate for the preparation of a corresponding lecture on this topic.
显示更多 [+] 显示较少 [-]Persistent aryl hydrocarbon receptor inducers increase with altitude, and estrogen-like disrupters are low in soils of the Alps
2011
Levy, Walkiria | Henkelmann, Bernhard | Bernhöft, Silke | Bovee, Toine | Buegger, Franz | Jakobi, Gert | Kirchner, Manfred | Bassan, Rodolfo | Kräuchi, Norbert | Moche, Wolfgang | Offenthaler, Ivo | Simoncic, Primoz | Weiss, Peter | Schramm, Karl-Werner
BACKGROUND: Soil samples from remote Alpine areas were analyzed for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans and polychlorinated biphenyls by high-resolution gas chromatography/high-resolution gas spectrometry. Additionally, the EROD micro-assay and a genetically modified yeast estrogen bioassay were carried out to determine persistent aryl hydrocarbon receptors (AhR) and estrogen receptors (ER) agonists, respectively. Regarding the AhR agonists, the toxicity equivalents of analytical and EROD determined values were compared, targeting both altitude of samples and their soil organic content. The ratio between bioassay derived equivalents and analytical determinations suggested no significant contribution of unknown AhR inducers in these sampling sites and some antagonism in soils with relatively high PCB loading. More CYP1A1 expression was induced at the highest sites or about 1400–1500 m a.s.l. along the altitude profiles. Surprisingly, no clear tendencies with the soil organic content were found for dioxin-like compounds. Mean values obtained in the present study were for ER agonists, 0.37 ± 0.12 pg 17ß-estradiol EQ g⁻¹ dry soil and 6.1 ± 4.2 pg TCDD-EQ g⁻¹ dry soil for AhR agonists. CONCLUSION: Low bioassay responses with a higher relative amount of AhR inducers than ER disrupters were detected, indicating the higher abundance of persistent dioxin-like than estrogen-like compounds in these forested mountainous areas.
显示更多 [+] 显示较少 [-]A possible new mechanism involved in ferro-cyanide metabolism by plants
2011
Yu, Xiao-Zhang | Li, Fan | Li, Kun
BACKGROUND, AIM, AND SCOPE: Ferro-cyanide is one of the commonly found species at cyanide-contaminated soils and groundwater. Unlike botanical metabolism of KCN via the β-cyanoalanine pathway, processes involved in the plant-mediated assimilation of ferro-cyanide are still unclear. The objective of this study was to investigate a possible mechanism involved in uptake and assimilation of ferro-cyanide by plants. MATERIALS AND METHODS: Detached roots of plants were exposed to ferro-cyanide in a closed-dark hydroponic system amended with HgCl2, AgNO3, LaCl3, tetraethylammonium chloride (TEACl), or Na3VO4, respectively, at 25 ± 0.5°C for 24 h. Total CN, free CN-, and dissolved Fe2+ were analyzed spectrophotometrically. Activity of β-cyanoalanine synthase involved in cyanide assimilation was also assayed using detached roots of plants in vivo. RESULTS: Dissociation of ferro-cyanide [FeII(CN)6]-4 to free CN- and Fe2+ in solution was negligible. The applied inhibitors did not show any significant impact on the uptake of ferro-cyanide by soybean (Glycine max L. cv. JD 1) and hybrid willows (Salix matsudana Koidz × alba L.; p > 0.05), but rice (Oryza sativa L. cv. JY 98) was more susceptible to the inhibitors compared with the controls (p < 0.05). However, TEACl had the most severe effect on the assimilation of ferro-cyanide by soybean, hybrid willows, and maize (Zea mays L. cv. PA 78; p < 0.01), whereas AgNO3 was the most sensitive inhibitor to rice (p < 0.01). No measurable difference in β-cyanoalanine synthase activity of roots exposed to ferro-cyanide was observed compared with the control without any cyanides (p > 0.05), whereas roots exposed to KCN showed a considerable increase in enzyme activity (p < 0.05). CONCLUSIONS: Plants take up Fe2+ and CN- as a whole complex, and in vivo dissociation to free CN- is not prerequisite during the botanical assimilation of ferro-cyanide. Ferro-cyanide is likely metabolized by plants directly through an unknown pathway rather than the β-cyanoalanine pathway.
显示更多 [+] 显示较少 [-]Effects of basin topography and monsoon conditions on transport and occurrence of atmospheric PCDD/Fs in the Taichung Basin
2011
Huang, Chao-Kai | Liang, Jeng-Jong
BACKGROUND, AIM, AND SCOPE: Topographical and meteorological factors, such as monsoons, can drastically affect ambient dioxin levels. In order to better understand these phenomena, four sampling lines (comprising 16 sampling sites) were selected in accordance with the topographical characteristics and the transport paths of the Taichung Basin. MATERIALS AND METHODS: The ambient air samples were simultaneously collected according to US EPA TO-9A. Seventeen polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed by a high-resolution gas chromatograph/high-resolution mass spectrometer. RESULTS: Field measurements indicated that, during monsoons, PCDD/Fs concentrations varied from 128 to 4,230 fg m−3. Two locations, the pass between two tablelands and the valley in front of a mountain, had the highest PCDD/Fs concentrations; those concentrations were about two to five times greater than the average concentration. There were 189 analyses of 11 kinds of PCDD/Fs emission sources used to develop emission fingerprints for a CMB8.2 simulation. Chemical mass balance (CMB8.2) model simulation with PCDD/Fs and surface wind field measurements were performed. Results of CMB8.2 modeling indicated that the major source of most sites was secondary copper smelting. CONCLUSIONS: The CMB8.2 model indicated the effects of hills and river valleys on pollutant transport. Results indicated that secondary copper smelting must be controlled to reduce the ambient concentrations of PCDD/Fs in the Taichung Basin.
显示更多 [+] 显示较少 [-]Source apportionment of the ionic components in precipitation over an urban region in Western India
2011
Sunder Raman, Ramya | Ramachandran, S
Introduction Inorganic ion concentrations in event-based wet-only precipitation samples collected during the south-west (SW) monsoon at an urban location in Western India, Ahmedabad between July 2000 and September 2002 were measured by Rastogi and Sarin (2007). Methods For the first time at a location in India, an advanced factor analysis model was retrospectively applied to the measured concentrations of ions (Rastogi and Sarin 2007) in precipitation for source apportionment. Positive matrix factorization resolved five factors, including crustal material, sea salt, nitrate/sulfate-rich factor, ammonium-rich factor, and free acidity. Results and discussion Amongst the model-resolved factors, crustal material was the highest contributor to the total dissolved solids (TDS) accounting for 44.1% on average. Potential source contribution function (PSCF) analysis identified source locations along the eastern coast of Somalia, Yemen, Oman, and the United Arab Emirates for this factor. Sea salt was the second highest contributor accounting for 29.8%. The potential source regions of this factor were also identified in the Arabian Sea and the southern Indian Ocean along the coast of Africa, and the Arabian Gulf. This study also examined the spatial relationships between the source locations of chemical species in precipitation and in ambient aerosol (resolved in an earlier study). Conclusions Crustal material was the highest contributor to TDS at the study location. Spatial relationships between aerosol and precipitation factor source regions suggested that below-cloud scavenging of aerosol particles was a likely contributor to the chemical species apportioned to various precipitation factors. Additionally, source types of chemical species in precipitation resolved in this study were qualitatively compared with those identified at other locations in India. The comparison showed that soil was an important contributor to the dissolved mass of chemical species in precipitation at all locations in India.
显示更多 [+] 显示较少 [-]Anomalous low tropospheric column ozone over Eastern India during the severe drought event of monsoon 2002: a case study
2011
Ghude, Sachin D. | Kulkarni, Santosh H. | Kulkarni, Pavan S. | Kanawade, Vijay P. | Fadnavis, Suvarna | Pokhrel, Samir | Jena, Chinmay | Beig, G. | Bortoli, D.
BACKGROUND, AIM, AND SCOPE: The present study is an attempt to examine some of the probable causes of the unusually low tropospheric column ozone observed over eastern India during the exceptional drought event in July 2002. METHOD: We examined horizontal wind and omega (vertical velocity) anomalies over the Indian region to understand the large-scale dynamical processes which prevailed in July 2002. We also examined anomalies in tropospheric carbon monoxide (CO), an important ozone precursor, and observed low CO mixing ratio in the free troposphere in 2002 over eastern India. RESULTS AND DISCUSSION: It was found that instead of a normal large-scale ascent, the air was descending in the middle and lower troposphere over a vast part of India. This configuration was apparently responsible for the less convective upwelling of precursors and likely caused less photochemical ozone formation in the free troposphere over eastern India in July 2002. CONCLUSION: The insight gained from this case study will hopefully provide a better understanding of the process controlling the distribution of the tropospheric ozone over the Indian region.
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