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Estimating nitrous oxide emission flux from arable lands in China using improved background emission and fertilizer-induced emission factors
2015
Chen, Jinsong | Cao, Wenzhi | Li, Ying | Cao, Di | Wang, Feifei
A nitrous oxide (N2O) emission database was compiled for arable land (284 measurements from 62 studies) to establish predictive models for building a greenhouse gas emission inventory in China. Arable lands were grouped into dry land and rice paddy based on the IPCC 2006 guidelines. The results of the meta analysis show that the annual mean N2O fluxes from dry land and rice paddy were 4.69±4.62 (SD) and 5.89±3.23kg N2O–N ha–1 yr–1. Fertilizer–induced N2O emission factors were 0.68±0.41% for dry land, and 0.49±0.43% for rice paddy. The relationship between N2O flux from arable lands and various environmental variables were analyzed, and the magnitude of N2O emissions from zero mineral N addition control plots (background emission) was determined based on precipitation. Based on the above background emissions and correlation coefficients, two new predictive models were established to estimate N2O emissions from arable lands in China. Comparison showed that the precipitation–rectified background emissions could largely improve the model predictions, and the two new models had better performance than the 1996 IPCC guideline method. Therefore, it is strongly recommended that the important local environmental variables be included in the estimates when compiling a national N2O emission inventory.
Show more [+] Less [-]Trends in indoor–outdoor PM2.5 research: A systematic review of studies conducted during the last decade (2003–2013)
2015
Mohammed, Mohammed O.A. | Song, Wei–Wei | Ma, Wan–Li | Li, Wen–Long | Ambuchi, John J. | Thabit, Mohammed | Li, Yi–Fan
There has been growing concern about potential health risks from exposure to PM2.5 (fine particulate matter). The importance of conducting simultaneous indoor and outdoor measurements emerged because people, especially in developed countries, spend more than 90% of their time indoors. Great spatial and temporal variations in human exposure to PM2.5 have recently been reported. This review aims to identify the main research areas that have attracted recent attention, any possible gaps in the measurements of PM2.5 in various microenvironments, and the relationships between indoor and outdoor concentrations. This study also provides recommendations for further studies on PM2.5 measurement methods and exposure levels. To achieve these goals, this review included articles published online from 2003 to 2013 in the Science Direct and Web of Science databases. In the initial screening stage, 113 abstracts selected while 61 articles were remained for full review. The reviewed studies consistently showed positive correlations between indoor and outdoor PM2.5. Sulfate/sulfur concentrations were used intensively for calculating the infiltration factor (FINF). The higher FINF indicated high infiltration of outdoor PM2.5 into indoor areas. Great percentage (42%) of the reviewed filter–based studies was conducted in Europe, followed by a similar amount (38%) in the USA, and 20% in Asia, indicating a lack in PM2.5 research in other parts of the world. It was difficult to conclude that ambient fixed–site monitoring provided accurate estimations of actual exposure to PM2.5– Studies shown trends of higher personal concentrations compared to indoor and outdoor ones. Higher indoor levels of OC (organic carbon), compared to outdoor levels, were consistently reported. The opposite trend was true for EC (elemental carbon), and there were higher indoor OC/EC ratios than outdoor OC/EC ratios. There was a consistent general trend of a high (r>0.70) correlation between indoor and outdoor EC, while the correlation between indoor and outdoor OC was much weaker (r=022–0.75). The higher indoor OC/EC ratios, compared to the outdoor OC/EC ratios, reflects multiple sources of indoor OC. Sulfate (SO42–), nitrate (NO3–), and ammonium (NH4+) were primary contributors to PM2.5 mass.
Show more [+] Less [-]Integrated environmental mapping and monitoring, a methodological approach to optimise knowledge gathering and sampling strategy
2015
Nilssen, Ingunn | Ødegård, Øyvind | Sørensen, Asgeir J. | Johnsen, Geir | Moline, Mark A. | Berge, Jørgen
New technology has led to new opportunities for a holistic environmental monitoring approach adjusted to purpose and object of interest. The proposed integrated environmental mapping and monitoring (IEMM) concept, presented in this paper, describes the different steps in such a system from mission of survey to selection of parameters, sensors, sensor platforms, data collection, data storage, analysis and to data interpretation for reliable decision making. The system is generic; it can be used by authorities, industry and academia and is useful for planning- and operational phases. In the planning process the systematic approach is also ideal to identify areas with gap of knowledge. The critical stages of the concept is discussed and exemplified by two case studies, one environmental mapping and one monitoring case. As an operational system, the IEMM concept can contribute to an optimised integrated environmental mapping and monitoring for knowledge generation as basis for decision making.
Show more [+] Less [-]An assessment of PCB and PBDE contamination in two tropical dolphin species from the Southeastern Brazilian coast
2015
Lavandier, Ricardo | Arêas, Jennifer | Dias, Patrick S. | Taniguchi, Satie | Montone, Rosalinda | de Moura, Jailson Fulgencio | Quinete, Natalia | Siciliano, Salvatore | Moreira, Isabel
PCBs and PBDEs were determined in two dolphin species, Sotalia guianensis and Steno bredanensis, from an upwelling system off the Central-northern coast of Rio de Janeiro, Brazil. PCB levels varied from 0.040 to 0.75μgg−1lw in muscles and from 0.022 to 1.32μgg−1lw in liver samples from S. guianensis. In S. bredanensis, values varied from 0.085 to 11.3μgg−1lw in muscles and from 0.024 to 18.6μgg−1lw in livers. PCB-138, -153 and -180 were the major PCB congeners detected in both species, while BDE-47 was the predominant PBDE congener found in both species. Higher concentrations in S. bredanensis were possibly related to the different feeding habits for both delphinid species. These results contribute to extend the database on organic contamination in cetaceans from the southern hemisphere, understanding their distribution and environmental fate in Southeastern Brazil.
Show more [+] Less [-]Optimizing landfill site selection by using land classification maps
2015
Eskandari, M. | Homaee, M. | Mahmoodi, S. | Pazira, E. | Van Genuchten, M. Th
Municipal solid waste disposal is a major environmental concern throughout the world. Proper landfill siting involves many environmental, economic, technical, and sociocultural challenges. In this study, a new quantitative method for landfill siting that reduces the number of evaluation criteria, simplifies siting procedures, and enhances the utility of available land evaluation maps was proposed. The method is demonstrated by selecting a suitable landfill site near the city of Marvdasht in Iran. The approach involves two separate stages. First, necessary criteria for preliminary landfill siting using four constraints and eight factors were obtained from a land classification map initially prepared for irrigation purposes. Thereafter, the criteria were standardized using a rating approach and then weighted to obtain a suitability map for landfill siting, with ratings in a 0–1 domain and divided into five suitability classes. Results were almost identical to those obtained with a more traditional environmental landfill siting approach. Because of far fewer evaluation criteria, the proposed weighting method was much easier to implement while producing a more convincing database for landfill siting. The classification map also considered land productivity. In the second stage, the six best alternative sites were evaluated for final landfill siting using four additional criteria. Sensitivity analyses were furthermore conducted to assess the stability of the obtained ranking. Results indicate that the method provides a precise siting procedure that should convince all pertinent stakeholders.
Show more [+] Less [-]Dioxins in the semen of men with infertility
2015
Galimova, E. F. | Amirova, Z. K. | Galimov, Sh. N.
The purpose of the present study was to assess ejaculate contamination by polychlorinated dibenzo-p-dioxins/furans in male infertility. The database of 168 infertile and 49 fertile men was included in the study. Dioxin content was determined using gas chromatography/high-resolution mass spectrometry (GC/HRMS). In the ejaculate of infertile men, the content of dioxins and furans was 2.2–2.3 times higher than in fertile donors. The maximum level of the most toxic dioxin congener was detected in pathospermia. Contamination of semen of infertile men by polychlorinated dibenzo-p-dioxins/furans supports the hypothesis about the relationship between environmental factors and reproductive health.
Show more [+] Less [-]Changes in the abundance of sugars and sugar-like compounds in tall fescue (Festuca arundinacea) due to growth in naphthalene-treated sand
2015
Balasubramaniyam, Anuluxshy | Harvey, Patricia J
The hydrophilic metabolome of tall fescue (Festuca arundinacea) adapted to grow in naphthalene-treated sand (0.8 g kg⁻¹sand dw) was analysed using gas chromatography-mass spectrometry, and peaks corresponding to the more abundant compounds were tentatively identified from analysis of their mass spectral features and reference to the NIST Mass Spectral Database. Particular attention was paid to sugars as they are known to play important roles as stress regulators in plants. The results showed that the abundance of sugars was greater in the roots but lesser in the shoots of treated plants when compared to their control counterparts. The results for indole acetic acid (IAA) were notable: IAA was prominently less in the treated roots compared to shoots, and in treated shoots, IAA was particularly subdued compared to untreated shoots consistent with IAA degradation in treated plant tissues. The differences in the molecular phenotype between control and treated plants were expressed in root structural differences. The treated roots were modified to have greater suberisation, enhanced thickening in the endodermis and distortions in the cortical zone as demonstrated through scanning electron and epi-fluorescence microscopy.
Show more [+] Less [-]Temporal trend, geographic distribution, and publication quality in asbestos research
2015
Ugolini, Donatella | Bonassi, Stefano | Cristaudo, Alfonso | Leoncini, Giacomo | Ratto, Giovanni Battista | Neri, Monica
Asbestos is a well-known cause of cancer and respiratory diseases. The aim of the current study was to investigate the scientific production in asbestos research evaluating temporal trend, geographic distribution, impact factor (IF) of published literature, and taking into account socioeconomic variables. The PubMed database was searched starting from 1970. Publication numbers and IF were evaluated as absolute values and after standardization by population and gross domestic product (GDP). Six thousand nine hundred seven articles related to asbestos were retrieved. Publications grew steeply in the 1970s, leveled off in the 1980s, decreased in the 1990s, and then increased again. Mesothelioma, lung neoplasms, and occupational diseases are the most commonly used keywords. In the period of 1988–2011, 4220 citations were retrieved, 3187 of whom had an impact factor. The US, Italy, and the UK were the most productive countries. European countries published about 20 % more asbestos-related articles than the US, although the latter reached a higher mean IF, ranking second after Australia. When the national scientific production (sum of IF) was compared taking into account socioeconomic variables, Australia and Scandinavian countries performed very well, opposite to all main asbestos producers like Russia, China, and Brazil (except for Canada). The American Journal of Industrial Medicine and the Italian La Medicina del Lavoro published the highest numbers of articles. This study provides the first bibliometric analysis of scientific production in asbestos research. Interest appears to be higher in selected countries, with strong national features, and is growing again in the new millennium.
Show more [+] Less [-]Large-scale monitoring and assessment of metal contamination in surface water of the Selenga River Basin (2007–2009)
2015
Nadmitov, Bulat | Hong, Seongjin | In Kang, Sang | Chu, Jang Min | Gomboev, Bair | Janchivdorj, Lunten | Lee, Chang Hee | Khim, Jong Seong
An extensive and year-round survey was conducted to assess metal pollution in vast watershed areas of the Selenga River Basin (2007–2009), which provided baseline heavy metal database for the future management. Sources and environmental hazard and risk indices associated with metal pollution were evidenced across the countries of Mongolia and Russia (Buryatia Republic). In general, the concentrations of heavy metals in river water of Mongolia were greater than those of Russia, expect for the upstream of the Dzhida River in Russia. The spatial distribution generally indicated that metal pollution in the Selenga River was mainly associated with the activities in the Mongolian upstream regions. Similar pollution sources of metals between river water and wastewater associated with surrounding activities were found across the industrial and mining areas. Compositional patterns of metals suggested their sources were independent of each other, with hot spots in certain sites. Our measurements indicated that about 63 % of the locations surveyed (48 of 76) exceeded the critical heavy metal pollution index of 100, identifying possible harmful effects on aquatic ecosystems through metal pollution. Zinc was found to be the chemical of priority concern, as more than half of the locations exceeded the corresponding water quality guideline. Other metals including Mn, Fe, Cr, Cu, and As might be problematic in the Selenga River Basin considering the occurrence and their concentrations. Results of our extensive survey during the period of 3 years indicated that urgent action would be necessary in timely manner to improve water quality and mitigate the impact of heavy metals on aquatic environment of the Selenga River Basin.
Show more [+] Less [-]Electrical resistivity characteristics of diesel oil-contaminated kaolin clay and a resistivity-based detection method
2015
Liu, Zhibin | Liu, Songyu | Cai, Yi | Fang, Wei
As the dielectric constant and conductivity of petroleum products are different from those of the pore water in soil, the electrical resistivity characteristics of oil-contaminated soil will be changed by the corresponding oil type and content. The contaminated soil specimens were manually prepared by static compaction method in the laboratory with commercial kaolin clay and diesel oil. The water content and dry density of the first group of soil specimens were controlled at 10 % and 1.58 g/cm³. Corresponding electrical resistivities of the contaminated specimens were measured at the curing periods of 7, 14, and 28 and 90, 120, and 210 days on a modified oedometer cell with an LCR meter. Then, the electrical resistivity characteristics of diesel oil-contaminated kaolin clay were discussed. In order to realize a resistivity-based oil detection method, the other group of oil-contaminated kaolin clay specimens was also made and tested, but the initial water content, oil content, and dry density were controlled at 0~18 %, 0~18 %, 1.30~1.95 g/cm³, respectively. Based on the test data, a resistivity-based artificial neural network (ANN) was developed. It was found that the electrical resistivity of kaolin clay decreased with the increase of oil content. Moreover, there was a good nonlinear relationship between electrical resistivity and corresponding oil content when the water content and dry density were kept constant. The decreasing velocity of the electrical resistivity of oil-contaminated kaolin clay was higher before the oil content of 12 % than after 12 %, which indicated a transition of the soil from pore water-controlled into oil-controlled electrical resistivity characteristics. Through microstructural analysis, the decrease of electrical resistivity could be explained by the increase of saturation degree together with the collapse of the electrical double layer. Environmental scanning electron microscopy (ESEM) photos indicated that the diesel oil in kaolin clay normally had three kinds of effects including oil filling, coating, and bridging. Finally, a resistivity-based ANN model was established based on the database collected from the experiment data. The performance of the model was proved to be reasonably accepted, which puts forward a possible simple, economic, and effective tool to detect the oil content in contaminated clayey soils just with four basic parameters: wet density, dry density, measured moisture content, and electrical resistivity.
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