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Chemometric techniques in distribution, characterisation and source apportionment of polycyclic aromatic hydrocarbons (PAHS) in aquaculture sediments in Malaysia Full text
2013
Retnam, Ananthy | Zakaria, Mohamad Pauzi | Juahir, Hafizan | Ahmad Zaharin Aris, | Zali, Munirah Abdul | Kasim, Mohd Fadhil
This study investigated polycyclic aromatic hydrocarbons (PAHs) pollution in surface sediments within aquaculture areas in Peninsular Malaysia using chemometric techniques, forensics and univariate methods. The samples were analysed using soxhlet extraction, silica gel column clean-up and gas chromatography mass spectrometry. The total PAH concentrations ranged from 20 to 1841ng/g with a mean of 363ng/gdw. The application of chemometric techniques enabled clustering and discrimination of the aquaculture sediments into four groups according to the contamination levels. A combination of chemometric and molecular indices was used to identify the sources of PAHs, which could be attributed to vehicle emissions, oil combustion and biomass combustion. Source apportionment using absolute principle component scores–multiple linear regression showed that the main sources of PAHs are vehicle emissions 54%, oil 37% and biomass combustion 9%. Land-based pollution from vehicle emissions is the predominant contributor of PAHs in the aquaculture sediments of Peninsular Malaysia.
Show more [+] Less [-]A ten–year source apportionment study of ambient fine particulate matter in San Jose, California Full text
2013
Wang, Yungang | Hopke, Philip K.
Fine particulate matter (PM2.5) composition data from the Speciation Trends Network (STN) site in San Jose, CA, were analyzed by positive matrix factorization (PMF) using U.S. Environmental Protection Agency (EPA) PMF version 5.0. These data were 24–h average mass concentrations and compositions obtained from samples taken every third day from October 2002 to February 2012. The eight identified sources include secondary sulfate, secondary nitrate, fresh sea salt, aged sea salt, diesel emission, road salt, gasoline vehicles, and wood combustion. The contributions to PM2.5 of these eight sources were 13.1%, 20.0%, 5.5%, 7.8%, 9.4%, 5.1%, 14.8, and 24.3%, respectively. The Ni–related industrial source, which was detected in previous PMF analysis, was not identified in our study and a sharp decrease in Ni concentrations was observed after the end of 2004. The contribution of road dust source decreased significantly after 2004 (Mann–Whitney test, p<0.01), which is probably the result of the city wide enhanced street sweeping programs starting in 2005. A 40% reduction in the wood combustion PM2.5 contribution between winter 2008 and winter 2009 was found. This decrease could be attributed to the San Francisco Bay Area Air Quality Management District (BAAQMD) wood burning rule implemented in July 2008. In the future, the effectiveness and benefits of the wood burning rule could be evaluated using the multi–wavelength aethalometer delta–c method.
Show more [+] Less [-]Photosynthetically active radiation loss in the atmosphere in North China Full text
2013
Bai, Jianhui
Based on an understanding of energy, empirical formulas of hourly PAR (photosynthetically active radiation) under all sky conditions in North China were introduced and applied. An interesting and important phenomenon of the absorption of “water vapor factor” in 400–700 nm was studied and its real mechanism can be explained by the energy consumption of the substances (gas, liquid, solid–phase) through OH radicals during chemical and photochemical reactions. The PAR at the top of the atmosphere was estimated with good agreement. PAR losses in the atmosphere associated with “photochemical factor” and other materials in North China are spatial and seasonal dependence; their “annual” averages were 15.33 and 309.30 W m–2 in North China, respectively. The energy loss related to the “photochemical factor” should be considered in all kinds of basic processes in the atmosphere and model studies, including radiation transmission, photochemistry, air motion, and climate.
Show more [+] Less [-]Carbonaceous aerosols in a wood burning community in rural New Zealand Full text
2013
Ancelet, Travis | Davy, P. K. (Perry K.) | Trompetter, William J. | Markwitz, A. (Andreas) | Weatherburn, David C.
Particulate matter (PM) in Masterton, New Zealand, a rural community with a population of 20 000, was studied during the winter to gain an understanding of the carbonaceous species and their influence on PM concentrations. The average PM10 concentration during the winter was 21.0±14.8 µg m–3, of which 64% was PM2.5. PM2.5 concentrations were found to be the main cause of elevated PM10 concentrations, and were responsible for exceedances of the New Zealand National Environmental Standard for PM10. Carbonaceous species were 47 and 77% of the total PM10 and PM2.5, respectively. Organic carbon (OC) concentrations were always higher than elemental carbon (EC) concentrations. OC and EC concentrations showed excellent correlation with PM2.5 concentrations, suggesting that combustion processes were the dominant source of PM. Stable isotope analysis yielded δ13C values ranging from –24.9 to –27.6‰, which is indicative of wood combustion. Analysis of particle–phase PAHs by thermal desorption GC/MS yielded an average total PAH concentration of 38.9±25.9ng m–3, accounting for 0.3% of the PM2.5. Analysis of all of the results revealed that residential wood burning for domestic heating was the main source of PM pollution in Masterton. The results of this study suggest that a PM10 standard alone, particularly in areas where wood combustion is common, may not be providing an adequate level of protection for the exposed population.
Show more [+] Less [-]Correlation between atmospheric deposition of Cd, Hg and Pb and their concentrations in mosses specified for ecological land classes covering Europe Full text
2013
Schröder, Winfried | Pesch, Roland | Hertel, Anne | Schonrock, Simon | Harmens, Harry | Mills, Gina | Ilyin, Ilia
Referring to Europe as a whole and to single European countries, previous studies have shown that heavy metal concentrations in mosses (1) are primarily determined by atmospheric deposition of heavy metals; (2) are country and element–specific; and (3) agree well with respect to element–specific spatial patterns and temporal trends of atmospheric deposition of heavy metals. This paper investigates correlations between the concentrations of cadmium, lead and mercury in atmospheric deposition and mosses within the units of an ecological land classification of Europe. To this end, measurements from the 2005/2006 European moss survey and modeled atmospheric deposition in the previous three years were intersected with a map on ecologically defined land classes of Europe. Then, the minimum numbers of sampling sites required within the ecological land classes were computed. Considering spatial auto–correlations, subsequently the correlations between the concentrations of heavy metals in mosses and corresponding deposition were calculated and mapped for each of those ecological land classes containing moss sampling sites. It was concluded that the numbers of sampling sites within Europe and most participating countries as well as within most of the ecological land classes are sufficient for estimating the mean of measurements for the above mentioned three spatial levels within 20% of its true value with 95% confidence. Spatial patterns of correlations between the atmospheric deposition and bioaccumulation were shown to vary by element and ecologically defined land classes.
Show more [+] Less [-]Mercury in muscle and liver of ten ray species from Northwest Mexico Full text
2013
Ruelas-Inzunza, J. | Escobar-Sánchez, O. | Patrón-Gómez, J. | Moreno-Sánchez, X.G. | Murillo-Olmeda, A. | Spanopoulos-Hernández, M. | Corro-Espinosa, D.
We determined total mercury (Hg) distribution in muscle and liver of ten ray species and assessed health risk considering Hg levels in muscle and average consumption of rays in Mexico. Rays were collected from five sites in NW Mexico between March and November 2012. Hg concentrations ranged from 4.465μgg−1 in muscle of the longtail stingray Dasyatis longa to 0.036μgg−1 in liver of the diamond stingray Dasyatis dipterura. Considering all the individuals, Hg in muscle (1.612±1.322μgg−1) was significantly (p<0.05) higher than in liver (0.745±0.616μgg−1). Regarding local health risk assessment, none of the ray species may cause adverse effects on consumers.
Show more [+] Less [-]Tolerance of Brazilian brain coral Mussismilia braziliensis to sediment and organic matter inputs Full text
2013
Loiola, Miguel | Oliveira, Marília D.M. | Kikuchi, Ruy K.P.
In Brazil, where reefs occur in markedly turbid environments, the relationship between sedimentation/organic matter and corals is poorly known. Thus, the ex situ effects of sediment with and without organic matter over the ΔF/Fm and physical state of Mussismilia braziliensis were analyzed. The ΔF/Fm and coral physical state, evaluated through the susceptibility index to sedimentation (SI), were measured in seven colonies exposed to sedimentation (0–450mgcm−2day−1) free of organic matter after 45days of exposure, and in 12 colonies exposed to sedimentation (0–500mgcm−2day−1) with organic matter content (10%), in which case ΔF/Fm was measured after 72h and SI after 120h. In both cases there were effects of increasing sedimentation on the SI with no effect on ΔF/Fm. Despite the tolerance to high sedimentation rates shown by this coral, we noted that the presence of organic matter might reduce its tolerance to sedimentation stress.
Show more [+] Less [-]Is Jamaica a good model for understanding Caribbean coral reef dynamics? Full text
2013
Côté, Isabelle M. | Precht, William F. | Aronson, Richard B. | Gardner, Toby
Caribbean reefs have experienced unprecedented changes in the past 40years. A major hypothesis to explain shifts in reef community composition relates to declining herbivory. This hypothesis was developed largely based on observations of Jamaican reefs from the 1980s onward, but it is widely held to be relevant regionally. We use a region-wide dataset on benthic composition to examine how well the pattern of ecological change on Jamaican reefs is mirrored by other Caribbean reefs. The extent to which macroalgal cover exceeds coral cover on Jamaican reefs is an order of magnitude more extreme than seen elsewhere. We suggest that Jamaican reefs are not representative of the degradation trajectory of Caribbean reefs and management based on the Jamaican experience may not be relevant elsewhere. However, the recovery of Jamaican reefs following the return of urchins gives us hope that Caribbean reefs are more resilient to catastrophic disturbances than previously thought.
Show more [+] Less [-]Multi-metric index based on the seagrass Zostera noltii (ZoNI) for ecological quality assessment of coastal and estuarine systems in SW Iberian Peninsula Full text
2013
García-Marín, Patricia | Cabaço, Susana | Hernández, Ignacio | Vergara, Juan J. | Silva, João | Santos, Rui
The aim of this study was to develop an ecological quality index based on the seagrass Zostera noltii (ZoNI) according to the WFD requirements. Eleven Z. noltii meadows of SW Iberian Peninsula under contrasting levels of anthropogenic disturbance were considered: 5 sites in Ria Formosa (Portugal), and 6 sites in Spain (Huelva and Cadiz). Environmental quality was assessed through nutrients of the water column and seagrass variables from different organization levels; those variables were analyzed using PCA (47% of explained variance on the first component) to calculate the ecological quality ratio (that was significantly correlated to the environmental variables, R2=0.51, p<0.01) and the ecological quality status of the sites. As a result, 4 sites were classified as good, 6 sites as moderate and 3 sites as poor ecological status. The developed index ZoNI showed to be suitable to assess the ecological status of estuarine and coastal systems in SW Iberian Peninsula reflecting their water quality.
Show more [+] Less [-]Drivers of estuarine benthic species distribution patterns following a restoration of a seagrass bed: A functional trait analyses Full text
2013
Dolbeth, Marina | Cardoso, Patricia | Grilo, Tiago | Raffaelli, Dave | Pardal, Miguel Ângelo
We integrate information on functional diversity (FD) patterns from estuarine intertidal benthic communities from different habitats and along a temporal disturbance gradient, to understand the drivers of species coexistence patterns. Species and traits’ biomass levels seemed to be first determined by habitat filtering, selecting those traits better adapted to the biologically challenging estuarine environment. Within that subset of traits and within each habitat, biotic interactions were probably high, as evidenced by high α-diversity and community weighted mean differences. The former patterns hold for the disturbance/recovery scenario considered. However, as the estuary recovered, biomass became more distributed among different trait categories, consistent with increases in FD when the seagrass started to increase. Policy towards the restoration of seagrass bed and other biogenic structures, and improving the connectivity within adjacent systems were confirmed and suggested, as this would imply higher FD and potentially higher resilience to disturbance within the estuarine intertidal system.
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