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Characterization of atmospheric mercury at a suburban site of central China from wintertime to springtime Texto completo
2014
Hu, Qi–Hou | Kang, Hui | Li, Zheng | Wang, Yu–Suo | Ye, Pei–Pei | Zhang, Lu–Lu | Yu, Juan | Yu, Xia–Wei | Sun, Chen | Xie, Zhou–Qing
Atmospheric mercury exits primarily as gaseous mercury and particulate mercury (PHg). Change in the species of atmospheric mercury will pose significant impact on the biogeochemical process of mercury. Here total gaseous mercury (TGM) and total particulate mercury (TPM) were measured from heating season in wintertime to springtime with frequent dust storm during February to May 2009 in the suburban of Hefei, central China, where atmospheric mercury measurements were completely absent. The average concentrations of TGM and TPM were 2.57±1.37ng/m3 and 0.32±0.10ng/m3, respectively. Variations in the TGM were affected by both emissions and meteorological parameters. In the heating period (February), due to coal combustion TGM concentrations were significantly higher than those in the spring (March, April and May). A clear different diurnal variation in TGM concentration was also observed both in late winter and in spring, accompanying with the advance of sunrise. The percentage of total particulate mercury (TPM) in total atmospheric Hg ranged from 5.8%–19.2%, with relatively high levels appeared in March and April. PHg was mainly derived from direct emissions by coal combustion in February and May, while it was dominated by transformation from gaseous Hg on particles in March and April due to dust storms, which may result in more deposition of mercury to ecosystem.
Mostrar más [+] Menos [-]Conservation management options and actions: Putative decline of coral cover at Palmyra Atoll, Northern Line Islands, as a case study Texto completo
2014
Gardner, Jonathan P.A. | John Bartz, R. | Brainard, Russell E. | Collen, John D. | Dunbar, Robert B. | Garton, David W. | Powell, Sam
Localised loss of live coral cover at Palmyra Atoll (central Pacific Ocean) has been attributed to increased temperature and/or sedimentation arising from alterations made to the lagoon system. It has been hypothesised that a causeway spanning the lagoon hinders water circulation, resulting in warmer and/or more turbid water flowing towards a site of high coral cover and diversity (Coral Gardens). Analyses of a multi-site and multi-year data set revealed no differences in mean temperature or turbidity values on either side of the causeway and provided no evidence of significantly warmer or more turbid water at Coral Gardens. We conclude that the putative decline in live coral cover cannot be attributed to the presence of the causeway and that proposed management actions involving modification to the causeway cannot achieve the conservation outcomes suggested of them.
Mostrar más [+] Menos [-]Physicochemical characteristics of PM2.5: Low, middle, and high–income group homes in Agra, India–a case study Texto completo
2014
Singh, Pradyumn | Saini, Renuka | Taneja, Ajay
The present study shows the current scenario of the aggregate relation between income and pollution at the household level. The indoor sampling of fine particulate matter was conducted in low– middle– and high–income group homes in Agra City, the North Central region of India. The mean indoor concentrations of PM2.5 were 46.7μg/m3, 39.2μg/m3 and 25.6μg/m3 in low– middle– and high–income group homes respectively. The full–day variation revealed that the concentrations of fine particles were higher during morning and evening hours in all the three income group homes. The indoor meteorological parameters were also monitored. Using scanning electron microscopy coupled with energy dispersive x–ray spectrometer (SEM–EDS) chemical and elemental analysis of fine particles and their probable sources has been conducted in low– middle– high–income group homes. EDS spectra indicates the elemental composition of PM2.5 which can be distributed into following groups of particles i.e. C–O rich (54%), F rich (42%) and other (4%) in low–income group homes. In middle– and high–income group homes F rich (59–65%), C–O rich (32–37%) and other (3–4%) were observed in PM2.5. The SEM images of fine particles indicates that the particles are clustered into following groups i.e. aluminosilicates/silica particles, spherical carbon rich particles, nearly spherical fluorine rich particles, Mg–Si or Mg–Si–Al particles.
Mostrar más [+] Menos [-]A study of anthropogenic and climatic disturbance of the New River Estuary using a Bayesian belief network Texto completo
2014
Nojavan A., Farnaz | Qian, Song S. | Paerl, Hans W. | Reckhow, Kenneth H. | Albright, Elizabeth A.
The present paper utilizes a Bayesian Belief Network (BBN) approach to intuitively present and quantify our current understanding of the complex physical, chemical, and biological processes that lead to eutrophication in an estuarine ecosystem (New River Estuary, North Carolina, USA). The model is further used to explore the effects of plausible future climatic and nutrient pollution management scenarios on water quality indicators. The BBN, through visualizing the structure of the network, facilitates knowledge communication with managers/stakeholders who might not be experts in the underlying scientific disciplines. Moreover, the developed structure of the BBN is transferable to other comparable estuaries. The BBN nodes are discretized exploring a new approach called moment matching method. The conditional probability tables of the variables are driven by a large dataset (four years). Our results show interaction among various predictors and their impact on water quality indicators. The synergistic effects caution future management actions.
Mostrar más [+] Menos [-]De novo transcriptomic profile in the gonadal tissues of the intertidal whelk Reishia clavigera Texto completo
2014
Ho, Kevin K.Y. | Leung, Priscilla T.Y. | Ip, Jack C.H. | Qiu, J.W. | Leung, Kenneth M.Y.
The intertidal whelk Reishia clavigera (formerly named as Thais clavigera) is one of the most sensitive species to organotin-associated imposex. However, the limited information on mRNA transcriptome of the species has restricted the molecular investigation on such endocrine disruption. By means of Illumina sequencing, we obtained a global de novo transcriptome from the gonadal tissues of both male and female R. clavigera, with 197,324 assembled transcripts and 151,684 condensed non-redundant transcripts. Blast hit results from the NCBI’s non-redundant molluscan database showed that 28,948 transcripts were successfully annotated with significant matches at an e-value of ⩽1e−6. Among them, 1108 transcripts were assigned a well-defined gene ontology term. As the first transcriptomic study on the gonadal tissues of R. clavigera, this study has enhanced the information of mRNA transcriptome on this species and will thus facilitate mechanistic studies of chemical contaminants (e.g., organotins) on this common biomonitor species.
Mostrar más [+] Menos [-]The environmental release and fate of antibiotics Texto completo
2014
Manzetti, Sergio | Ghisi, Rossella
Antibiotics have been used as medical remedies for over 50years and have recently emerged as new pollutants in the environment. This review encompasses the fate of several antibiotics in the environment, including sulfonamides, nitrofurans, terfenadines, cephalosporins and cyclosporins. It investigates the cycle of transfer from humans and animals including their metabolic transformation. The results show that antibiotic metabolites are of considerable persistence and are localized to ground-water and drinking water supplies. Furthermore, the results also show that several phases of the cycle of antibiotics in the environment are not well understood, such as how low concentrations of antibiotic metabolites in the diet affect humans and animals. This review also shows that improved wastewater decontamination processes are remediating factors for these emerging pollutants. The results obtained here may help legislators and authorities in understanding the fate and transformation of antibiotics in the environment.
Mostrar más [+] Menos [-]Courage under fire: Seagrass persistence adjacent to a highly urbanised city–state Texto completo
2014
Yaakub, Siti Maryam | McKenzie, Len J. | Erftemeijer, Paul L.A. | Bouma, Tjeerd | Todd, Peter A.
Due to increasing development Southeast Asia’s coastlines are undergoing massive changes, but the associated impacts on marine habitats are poorly known. Singapore, a densely populated island city–state, is a quintessential example of coastal modification that has resulted in the (hitherto undocumented) loss of seagrass. We reconstructed the historic extent and diversity of local seagrass meadows through herbarium records and backwards extrapolation from contemporary seagrass locations. We also determined the current status of seagrass meadows using long-term monitoring data and identified the main threats to their presence in Singapore. Results show that, even though ∼45% of seagrass has been lost during the last five decades, species diversity remains stable. The main cause of seagrass loss was, and continues to be, land reclamation. We conclude that strict controls on terrestrial runoff and pollution have made it possible for seagrass to persist adjacent to this highly urbanised city–state.
Mostrar más [+] Menos [-]Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments Texto completo
2014
Quilliam, Richard S. | Jamieson, Julie | Oliver, David M.
Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments Texto completo
2014
Quilliam, Richard S. | Jamieson, Julie | Oliver, David M.
The revised Bathing Water Directive (rBWD) introduces more stringent standards for microbial water quality and promotes more pro-active management of the beach environment through the production of a bathing water profile (BWP). The aim of this study was to determine whether living seaweeds in the littoral zone are colonised by faecal indicator organisms (FIOs), and to quantify the survival dynamics of waterborne Escherichia coli in microcosms containing senescing seaweeds. Living seaweed (Fucus spiralis) was not associated with FIO colonisation, although could be providing a protected environment in the underlying sand. Senescing seaweeds enhanced waterborne E. coli survival compared to plastic debris, with the brown seaweed Laminaria saccharina facilitating greater E. coli persistence than either Chondrus crispus or Ulva lactuca. This has important implications for FIO survival on bathing beaches as the majority of beach-cast biomass is composed of brown seaweeds, which could support significant levels of FIOs.
Mostrar más [+] Menos [-]Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments Texto completo
2014
Quilliam, Richard | Jamieson, Julie | Oliver, David | Biological and Environmental Sciences | University of Stirling | Biological and Environmental Sciences | 0000-0001-7020-4410 | 0000-0002-6200-562X
The revised Bathing Water Directive (rBWD) introduces more stringent standards for microbial water quality and promotes more pro-active management of the beach environment through the production of a bathing water profile (BWP). The aim of this study was to determine whether living seaweeds in the littoral zone are colonised by faecal indicator organisms (FIOs), and to quantify the survival dynamics of waterborne Escherichia coli in microcosms containing senescing seaweeds. Living seaweed (Fucus spiralis) was not associated with FIO colonisation, although could be providing a protected environment in the underlying sand. Senescing seaweeds enhanced waterborne E. coli survival compared to plastic debris, with the brown seaweed Laminaria saccharina facilitating greater E. coli persistence than either Chondrus crispus or Ulva lactuca. This has important implications for FIO survival on bathing beaches as the majority of beach-cast biomass is composed of brown seaweeds, which could support significant levels of FIOs.
Mostrar más [+] Menos [-]Hierarchy of factors exerting an impact on nutrient load of the Baltic Sea and sustainable management of its drainage basin Texto completo
2014
Kiedrzyńska, Edyta | Jóźwik, Adam | Kiedrzyński, Marcin | Zalewski, Maciej
The aim of the paper was to evaluate 23 catchment factors that determine total phosphorus and total nitrogen load to the Baltic Sea. Standard correlation analysis and clustering were used. Both phosphorus and nitrogen loads were found to be positively related to the number of pigs and the human population associated with wastewater treatment plants (WWTPs) per km2, while the number of cattle and agricultural area were found to influence nitrogen rather than phosphorus load, and the area of forests is negatively related to loads of both nutrients. Clustering indicates an overall north–south pattern in the spatial co-occurrence of socio-ecological factors, with some exceptions discussed in the paper. Positive steps in the Baltic Sea region have already been taken, but much remains to be done. The development of coherent response policies to reduce eutrophication in the Baltic Sea should be based on a comprehensive knowledge base, an appropriate information strategy and learning alliance platform in each drainage river catchments.
Mostrar más [+] Menos [-]Metal contamination of estuarine intertidal sediments of Moreton Bay, Australia Texto completo
2014
Morelli, Guia | Gasparon, Massimo
Trace element concentrations in surface intertidal sediments were analyzed to assess the level of contamination along the western side of Moreton Bay (Australia). The environmental risks posed by metals were evaluated using sediment quality guidelines, the Risk Assessment Code (RAC) and enrichment relative to background levels. Chromium, Ni, and Cu are the main contributors to sediment pollution. Sediments are also enriched in Zn, Cd and Pb by 1.5–3 times the regional background. Zinc, Cd and Co may pose high to very high risk to the aquatic biota due to their potential bioavailability, while Ni, As, Cu, Pb and Cr may pose medium risk at some of the investigated sites. Results emphasize the importance of using different methods for the assessment of sediment pollution at an estuarine site.
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