Affiner votre recherche
Résultats 1951-1960 de 3,208
Impact of a phosphate fertilizer plant on the contamination of marine biota by heavy elements Texte intégral
2015
Aoun, Maria | Arnaudguilhem, Carine | El Samad, Omar | Khozam, Rola Bou | Łobiński, Ryszard
Due to their toxicity, persistence, and bioaccumulation, metals are important marine environment pollutants, especially in low renewal rate water such as the Mediterranean Sea, receiving a lot of untreated industrial waste. The impact of a phosphate fertilizer plant on the marine biota metal contamination was studied. Several types of organisms: crabs, mussels, patella and fish were collected from two areas of the Lebanese coast, one subjected to the impact of the plant and another away from it; samples were analyzed for Zn, U, Cr, V, Mn, Ni, Co, Cu, As, Cd and Pb by ICP-MS. Higher accumulation was in crabs, patella, and mussels. Fish accumulated principally Zn, Cu, and Cd; a difference was observed between species and tissues. Cytosol metal fractionation using size-exclusion LC-ICP-MS showed principally Pb, As, Co, and Mn in the low molecular weight fraction (<1.8 Da); Cd, Zn, and Cu in the metallothionein fraction (1.8–-18 k Da), and Ni in high molecular weight fraction (>20 kDa).
Afficher plus [+] Moins [-]Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species Texte intégral
2015
Barbera, Antonio C. | Borin, Maurizio | Cirelli, Giuseppe L. | Toscano, Attilio | Maucieri, Carmelo
This study investigates carbon dioxide (CO₂) and methane (CH₄) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m⁻²) followed by C. zizanioides (5.3 kg m⁻²) and C. papyrus (1.8 kg m⁻²). Significantly higher emissions of CO₂were detected in the summer, while CH₄emissions were maximum during spring. Cumulative CO₂emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m⁻², respectively, whereas M. giganteus emitted 3,395 g m⁻². Cumulative CH₄bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m⁻²and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH₄cumulative emission with 240.3 g m⁻². The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m⁻²) followed by C. zizanioides (3.78 kg m⁻²) and C. papyrus (1.89 kg m⁻²). To our knowledge, this is the first paper that presents preliminary results on CO₂and CH₄emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth.
Afficher plus [+] Moins [-]Community structure and nutrient level control the tolerance of autotrophic biofilm to silver contamination Texte intégral
2015
Leflaive, J. | Felten, V. | Ferriol, J. | Lamy, A. | Ten-Hage, L. | Bec, A. | Danger, M.
Autotrophic biofilms are complex and fundamental biological compartments of many aquatic ecosystems. Since microbial species differ in their sensitivity to stressors, biofilms have long been proposed for assessing the quality of aquatic ecosystems. Among the many stressors impacting aquatic ecosystems, eutrophication and metal pollution are certainly the most common. Despite that these stressors often occur together, their effects on biofilms have been far much studied separately than interactively. In this study, we evaluated the interactive effects of silver (Ag), a reemerging contaminant, and phosphorus (P), a nutrient often associated with freshwater eutrophication, on the structure and functioning of two types of autotrophic biofilms, one dominated by diatoms and another one dominated by cyanobacteria. We hypothesized that P would alleviate the toxic effects of Ag, either directly, through the contribution of P in metal detoxification processes, or indirectly, through P-mediated shifts in biofilm community compositions and associated divergences in metal tolerance. Results showed that Ag impacted biofilm community structure and functioning but only at unrealistic concentrations (50 μg/L). P availability led to significant shifts in biofilm community composition, these changes being more pronounced in diatom- than those in cyanobacteria-dominated biofilm. In addition, P tended to reduce the impact of Ag but only for the cyanobacteria-dominated biofilm. More generally, our results highlight the preponderant role of the initial community structure and nutrient level on biofilm response to metallic pollutants.
Afficher plus [+] Moins [-]Emerging and priority contaminants with endocrine active potentials in sediments and fish from the River Po (Italy) Texte intégral
2015
Luigi, Viganò | Giuseppe, Mascolo | Claudio, Roscioli
There is a substantial lack of information on most priority pollutants, related contamination trends, and (eco)toxicological risks for the major Italian watercourse, the River Po. Targeting substances of various uses and origins, this study provides the first systematic data for the River Po on a wide set of priority and emerging chemicals, all characterized by endocrine-active potentials. Flame retardants, natural and synthetic hormones, surfactants, personal care products, legacy pollutants, and other chemicals have been investigated in sediments from the River Po and its tributary, the River Lambro, as well as in four fish species from the final section of the main river. With few exceptions, all chemicals investigated could be tracked in the sediments of the main Italian river for tens or hundreds of kilometres downstream from the Lambro tributary. Nevertheless, the results indicate that most of these contaminants, i.e., TBBPA, TCBPA, TBBPA-bis, DBDPE, HBCD, BPA, OP, TCS, TCC, AHTN, HHCB, and DDT, individually pose a negligible risk to the River Po. In contrast, PBDE, PCB, natural and synthetic estrogens, and to a much lower extent NP, were found at levels of concern either to aquatic life or human health. Adverse biological effects and prohibition of fish consumption deserve research attention and management initiatives, also considering the transport of contaminated sediments to transitional and coastal environments of the Italian river.
Afficher plus [+] Moins [-]Ecological, morphological, and histological studies on Blaps polycresta (Coleoptera: Tenebrionidae) as biomonitors of cadmium soil pollution Texte intégral
2015
Osman, Wafaa | M. El-Samad, Lamia | Mokhamer, EL-Hassan | El-Touhamy, Aya | Shonouda, Mourad
Soil pollution in Egypt became far more serious than before due to either the heavy usage of different toxic pesticides or aerosol deposition of industrial pollutants. The present mentioned ground beetle, Blaps polycresta Tschinkel 1975 (Coleoptera: Tenebrionidae), showed ecological, morphological, and histological alterations in adult insects as biomonitors. Two cultivated sites (reference and polluted) were chosen for sampling the insects. The results indicated a significant increase in soil cadmium concentration of the polluted site leading to sex-specific difference in cadmium accumulation in gonads and alimentary canal of insects that being higher in males than females. The cadmium pollution leads significantly to a decrease in population density, a reduction in body weight, an increase in mortality rate, and an increase in sex ratio of the insects. The results also revealed a striking decrease in body length of the polluted insects with a marked increase in the percentage of deformed gonads and alimentary canal of both sexes. Some histopathological alterations were also recorded in testis, ovary, and midgut of the polluted insects. Our results confirmed that beetles are a good bioindicator for soil pollution, and the different studied parameters could be easily employed as sensitive monitors for cadmium soil pollution.
Afficher plus [+] Moins [-]Threats to water resources from hexachlorobenzene waste at Kalush City (Ukraine)—a review of the risks and the remediation options Texte intégral
2015
Lysychenko, Georgii | Weber, Roland | Kovach, Valeria | Gertsiuk, Modest | Watson, Alan | Krasnova, Iryna
The production of chlorinated solvents such as tetrachloroethylene and tetrachloromethane has resulted in large stockpiles of unintentionally produced persistent organic pollutants (POPs) including high content of hexachlorobenzene (HCB waste). HCB waste of 15,000 t arising from the production of chlorinated solvents at the Kalush factory in Ukraine was landfilled. In 2008, it was discovered that HCB and other pollutants were escaping from the landfill into local environment including the Sapogi–Limnytsia Rivers, tributaries of the Dniester River. This showed that the HCB waste was not appropriately contained and represented a threat to the Dniester River basin. A Presidential Decree of Ukraine was therefore issued requiring remediation of the site and excavation of the waste. Between 2010 and 2013, approximately 29,445 t of HCB waste and associated contaminated soil was excavated and exported to various EU countries for incineration. This excavation revealed that these wastes can corrode through their drums within a few decades with release of pollutants. Other sites at which chlorinated solvents were produced should therefore be assessed for possible similar pollution. Despite the remediation efforts and the excavation of the landfill, the Kalush area remains a POP-contaminated site requiring further assessment. A part of the waste was exported to Poland and is stored close to the Baltic Sea and is treated in an incinerator with small capacity over a time frame of years. This case and recent similar cases reveal that the control of POP waste for destruction even in EU countries needs to be improved.
Afficher plus [+] Moins [-]The pollution intensity of Australian power stations: a case study of the value of the National Pollutant Inventory (NPI) Texte intégral
2015
Tang, Minmeng | Mudd, Gavin M.
This paper presents a comprehensive analysis of the pollutant emissions from electrical generation facilities reported to Australia’s National Pollutant Inventory (NPI). The data, in terms of pollutant intensity with respect to generation capacity and fuel source, show significant variability. Based on reported data, the dominant pathway and environmental segment for emissions is point-source air emissions. Surprisingly, pollutant emissions from power stations are generally a very small fraction of Australia’s facility and diffuse emissions, except for F, HCl, NOₓ, PM₂.₅, SO₂ and H₂SO₄ (where it constitutes between 30 and 90 % of emissions). In general, natural gas and diesel facilities have higher organic pollutant intensities, while black and brown coal have higher metal/metalloid pollutant intensities and there is a wide variability for inorganic pollutant intensities. When examining pollutant intensities with respect to capacity, there is very little evidence to show that increased scale leads to more efficient operation or lower pollutant intensity. Another important finding is that the pollutant loads associated with transfers and reuse are substantial, and often represent most of the reported pollutants from a given generation facility. Finally, given the issues identified with the NPI data and its use, some possible improvements include the following: (i) linking site generation data to NPI data (especially generation data, i.e., MWh); (ii) better validation and documentation of emissions factors, especially the methods used to derive and report estimates to the NPI; (iii) using NPI data to undertake comparative life cycle impact assessment studies of different power stations and fuel/energy sources, or even intensive industrial regions (especially from a toxicity perspective) and (iv) linking NPI data in a given region to ongoing environmental monitoring, so that loads can be linked to concentrations for particular pollutants and the relevant guidelines (e.g., air, water, human health). Pollutant inventory systems are clearly valuable tools in understanding pollution burdens and ongoing analysis of the growing body of data should help to further improve environmental and public health outcomes. Overall, this study provides a valuable insight into the current status of pollutant intensities from Australia’s electrical generation facilities and should be a valuable benchmark for future studies and international comparisons.
Afficher plus [+] Moins [-]Legionella detection and subgrouping in water air-conditioning cooling tower systems in Kuwait Texte intégral
2015
Al-Matawah, Qadreyah | Al-Zenki, Sameer | Al-Azmi, Ahmad | Al-Waalan, Tahani | Al-Salameen, Fadila | Hejji, Ahmad Ben
The main aim of the study was to test for the presence of Legionnaires’ disease-causing microorganisms in air-conditioned buildings in Kuwait using molecular technologies. For this purpose, 547 samples were collected from 38 cooling towers for the analysis of Legionella pneumophila. These samples included those from water (n = 178), air (n = 231), and swabs (n = 138). Out of the 547 samples, 226 (41 %) samples were presumptive positive for L. pneumophila, with L. pneumophila viable counts in the positive water samples ranging from 1 to 88 CFU/ml. Of the Legionella culture-positive samples, 204 isolates were examined by latex agglutination. These isolates were predominately identified as L. pneumophila serogroup (sg) 2–14. Using the Dresden panel of monoclonal antibodies, 74 representatives isolates were further serogrouped. Results showed that 51 % of the isolates belonged to serogroup 7 followed by 1 (18 %) and 3 (18 %). Serogroups 4 (4 %) and 10 (7 %) were isolated at a lower frequency, and two isolates could not be assigned to a serogroup. These results indicate the wide prevalence of L. pneumophila serogroup 7 as the predominant serogroup at the selected sampling sites. Furthermore, the 74 L. pneumophila (sg1 = 13; sg3 = 13; sg4 = 3; sg7 = 38; sg10 = 5; sgX = 2) isolates were genotyped using the seven gene protocol sequence-based typing (SBT) scheme developed by the European Working Group for Legionella Infections (EWGLI). The results show that Legionella isolates were discriminated into nine distinct sequence typing (ST) profiles, five of which were new to the SBT database of EWGLI. Additionally, all of the ST1 serogroup 1 isolates were of the OLDA/Oxford subgroup. These baseline data will form the basis for the development of a Legionella environmental surveillance program and used for future epidemiological investigations.
Afficher plus [+] Moins [-]Selected current-use pesticides (CUPs) in coastal and offshore sediments of Bohai and Yellow seas Texte intégral
2015
Zhong, Guangcai | Tang, Jianhui | Xie, Zhiyong | Mi, Wenying | Chen, Yingjun | Möller, Axel | Sturm, Renate | Zhang, Gan | Ebinghaus, Ralf
China is one of the largest producers, consumers, and traders for pesticides in the world. Currently, there are more than 600 pesticide-active substances registered in China, whereas few studies were conducted to improve our understanding of the occurrence and environmental impact of current-use pesticides (CUPs) in China’s environment. In this work, 72 surface sediment samples were taken from the coastal and offshore of Bohai and Yellow seas and were analyzed for six CUPs (trifluralin, dacthal, quintozene, endosulfan, chlorpyrifos, and dicofol) and two metabolites (pentachloroanisole and endosulfan sulfate). Sediment samples were categorized as estuarine or near-shore sediments (Laizhou Bay, Taozi Bay, Sishili Bay, and Jiaozhou Bay) and offshore sediments. Trifluralin, α-endosulfan, endosulfan sulfate, chlorpyrifos, dicofol, and pentachloroanisole were detected in more than 60 % of the samples. Dicofol was the predominant compound with concentrations mostly higher than 100 pg/g dry weight (dw) with the highest concentration of 18,000 pg/g dw. Concentrations of other compounds were mainly below 100 pg/g dw. CUP levels were much lower than the sediment screening benchmark calculated. The highest levels of α-endosulfan, endosulfan sulfate, trifluralin, and chlorpyrifos existed at Laizhou Bay, whereas pentachloroanisole and dicofol had highest mean concentrations at Jiaozhou Bay. Generally, no correlation between pesticide concentrations and total organic carbon was observed either for offshore samples or for near-shore samples.
Afficher plus [+] Moins [-]Bacterial communities of Beijing surface waters as revealed by 454 pyrosequencing of the 16S rRNA gene Texte intégral
2015
Wei, Yu-Mei | Wang, Jing-Qi | Liu, Ting-Ting | Kong, Wei-Wen | Chen, Nan | He, Xiao-Qing | Jin, Yi
As a better understanding of Beijing surface water ecosystems can provide clues for environmental management and public health, here, we report a study of the bacterial communities of five Beijing surface waters conducted using 454 pyrosequencing of 16S ribosomal RNA (rRNA) genes. We expected to observe a core bacterial community among the surface waters and differences in bacterial community abundance over the different locations of sampling. In this study, we obtained a total of 60,810 trimmed reads from the five samples after the removal of unqualified reads. Bacterial sequences from the five samples were classified into taxonomic classes using the default settings of the mothur platform. Our results provided insight into the bacterial community composition of surface waters and revealed that there was a core microbial community in the microbial populations of surface samples at different geographic locations, with 13 phyla and 40 genera in common. Our findings also revealed the differences in bacterial communities among five surface water samples obtained at different locations.
Afficher plus [+] Moins [-]