239 research outputs found
Total mercury concentrations in an industrialized catchment, the Thur River basin (north-eastern France): geochemical background level and contamination factors
No full textRiver bottom sediments and soils were collected from the industrialized Thur River basin (north-eastern France) to assess mercury contamination. The regional geochemical background level of total mercury was evaluated to calculate mercury contamination factors (Fc) in soils and river bottom sediments. Our estimate of the mean background mercury levels in river sediments and soils, not affected by human activities, was 232 ng g1 (range: 27–406 ng g1). Sediments contaminated by the effluent from a chlor-alkali plant yielded the highest contamination factors (Fc¼1784). Contamination factors of surficial soils within 1 km of the industrial site range from 6.3 to 43.6. This contamination is attributed to diffuse atmospheric deposition from this local plant. However, even upstream from this industrial area elevated contamination factors were recorded for river bottom sediments (Fc¼3.2 to 26.4) and for one alluvial soil profile (Fc¼10). This is possibly due to past pollution resulting from waste water discharges. Mercury contamination in the different horizons of alluvial soils is not correlated with soil organic carbon content, but may be the result of occasional accidental pollution arising from the introduction of contaminated suspended particulate matter by the Thur River during periods of flooding
Ravenelia piepenbringiae and Ravenelia hernandezii, two new rust species on Senegalia (Fabaceae, Mimosoideae) from Panama and Costa Rica
No full textTwo new rust species, Ravenelia piepenbringiae and R. hernandezii (Pucciniales) on Senegalia spp. (Fabaceae) are described from the Neotropics (Panama, Costa Rica). A key to the species on neotropical Senegalia spp. is provided. Molecular phylogenetic analyses based on 28S rDNA sequence data suggest that the representatives of Senegalia rusts distributed in the neotropics evolved independently from species known from South Africa. This is further supported by the teliospore morphology, which is characterised by uniseriate cysts in the neotropical Senegalia rusts and contrasting multiseriate cysts in the paleotropic Ravenelia species that infect this host genus
Table 1. Individual concentrations of HCH in the atmosphere in the Atlantic and the Southern Ocean
No full textConcentrations of alpha-HCH in atmospheric particle phase are showed in the blanket, and beta-HCH and gamma-HCH are below the method detection limits
Levels and distribution of Dechlorane Plus in coastal sediments of the Yellow Sea, North China
No full textDechlorane Plus (DP) has been determined in surface sediments from three Chinese coastal bays, e.g. Jiaozhou, Sishili and Taozi Bay in North China. DP concentrations ranged from <1.2 to 187 pg g(-1) dry weight (dw) (mean: 24.7 pg g(-1) dw) in Jiaozhou Bay, <1.2 to 135 pg g(-1) dw (mean 69.9 pg g(-1) dw) in Sishili Bay and <1.2 to 66.7 pg g(-1) dw (mean: 40.4 pg g(-1) dw) in Taozi Bay, respectively. Additionally, two dechlorinated species were quantified, which accounted for 0.6-5.1% of the Sigma DP concentration. The f(syn) values (syn-isomer/(syn- + anti-isomer)) in sediments from Jiaozhou Bay (mean 0.29) were close to the technical DP mixture (0.2-0.4), probably indicating local inputs of DP. In contrast, sediments in Sishili and Taozi Bay showed much lower f(syn) values (mean 0.16). During transportation the DP isomers are subject to stereo selective degradation which partly resulted in the relative enrichment of anti-DP in coastal sediments. (C) 2011 Elsevier Ltd. All rights reserved.Dechlorane Plus (DP) has been determined in surface sediments from three Chinese coastal bays, e.g. Jiaozhou, Sishili and Taozi Bay in North China. DP concentrations ranged from <1.2 to 187 pg g(-1) dry weight (dw) (mean: 24.7 pg g(-1) dw) in Jiaozhou Bay, <1.2 to 135 pg g(-1) dw (mean 69.9 pg g(-1) dw) in Sishili Bay and <1.2 to 66.7 pg g(-1) dw (mean: 40.4 pg g(-1) dw) in Taozi Bay, respectively. Additionally, two dechlorinated species were quantified, which accounted for 0.6-5.1% of the Sigma DP concentration
Table 2. Individual concentrations of HCH in surface seawater in the Atlantic and the Southern Ocean
No full textTable 2. Individual concentrations of HCH in surface seawater in the Atlantic and the Southern Ocea
Determination of atmospheric mercury and aerosol black carbon
No full textDuring the POLARSTERN cruise in the Nordic Seas and at the ice-camp, simultaneous measurements of atmospheric mercury and aerosol black carbon were performed by the GKSS group. The work was aimed at two subjects: 1. Although mercury usually occurs in trace concentrations, it is widely dispersed and occurs in its 'background concentration' on a global scale. For the determination of the natural backgrounds, measurements of mercury in remote areas were required to exclude anthropogenic influences. To our knowledge, atmospheric mercury concentrations in polar regions were still unknown. 2. Aerosol black carbon and potential oxidants for gaseous mercury such as ozone are the decisive factors for the transport and deposition properties of atmospheric mercury. For the validation and improvement of a European long range transport model as used by GKSS Research Centre, simultaneous measurements of atmospheric mercury and aerosol black carbon (soot) concentrations were required. (orig./SR)Reprinted from: Eicken, H.; Meinicke, J. (eds.): The expedition ARKTIS-IX/1 of RV 'Polarstern' in 1993. Published by Alfred-Wegener-Institut, Bremerhaven (DE) in Berichte zur Polarforschung v. 134 (1994), p. 48-52SIGLEAvailable from TIB Hannover: RA 3251(95/E/49) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Distribution and Air-Sea Exchange of Current-Use Pesticides (CUPs) from East Asia to the High Arctic Ocean
No full textSurface seawater and marine boundary layer air samples were collected on the ice-breaker R/V Xuelong (Snow Dragon) from the East China Sea to the high Arctic (33.23-84.5 degrees N) in July to September 2010 and have been analyzed for six current-use pesticides (CUPs): trifluralin, endosulfan, chlorothalonil, chlorpyrifos, dacthal, and dicofol. In all oceanic air samples, the six CUPs were detected, showing highest level (>100 pg/m(3)) in the Sea of Japan. Gaseous CUPs basically decreased from East Asia (between 36.6 and 45.1 degrees N) toward Bering and Chukchi Seas. The dissolved CUPs in ocean water ranged widely fromSurface seawater and marine boundary layer air samples were collected on the ice-breaker R/V Xuelong (Snow Dragon) from the East China Sea to the high Arctic (33.23-84.5 degrees N) in July to September 2010 and have been analyzed for six current-use pesticides (CUPs): trifluralin, endosulfan, chlorothalonil, chlorpyrifos, dacthal, and dicofol. In all oceanic air samples, the six CUPs were detected, showing highest level (>100 pg/m(3)) in the Sea of Japan. Gaseous CUPs basically decreased from East Asia (between 36.6 and 45.1 degrees N) toward Bering and Chukchi Seas. The dissolved CUPs in ocean water ranged widely from <MDL to 111 pg/L. Latitudinal trends of alpha-endosulfan, chlorpyrifos, and dicofol in seawater were roughly consistent with their latitudinal trends in air. Trifluralin in seawater was relatively high in the Sea of Japan (35.2 degrees N) and evenly distributed between 36.9 and 72.5 degrees N, but it remained below the detection limit at the highest northern latitudes in Chukchi Sea. In contrast with other CUPs, concentrations of chlorothalonil and dacthal were more abundant in Chukchi Sea and in East Asia. The air-sea gas exchange of CUPs was generally dominated by net deposition. Latitudinal trends of fugacity ratios of alpha-endosulfan, chlorothalonil, and dacthal showed stronger deposition of these compounds in East Asia than in Chukchi Sea, while trifluralin showed stronger deposition in Chukchi Sea (-455 +/- 245 pg/m(2)/day) than in the North Pacific (-241 +/-. 158 pg/m(2)/day). Air-sea gas exchange of chlorpyrifos varied from net volatilizaiton in East Asia (<40 degrees N) to equilibrium or net deposition in the North Pacific and the Arctic
Distribution and long-range transport of polyfluoroalkyl substances in the Arctic, Atlantic Ocean and Antarctic coast
No full textThe global distribution and long-range transport of polyfluoroalkyl substances (PFASs) were investigated using seawater samples collected from the Greenland Sea, East Atlantic Ocean and the Southern Ocean in 2009-2010. Elevated levels of Sigma PFASs were detected in the North Atlantic Ocean with the concentrations ranging from 130 to 650 pg/L In the Greenland Sea, the Sigma PFASs concentrations ranged from 45 to 280 pg/L, and five most frequently detected compounds were perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS). PFOA (15 pg/L) and PFOS (25-45 pg/L) were occasionally found in the Southern Ocean. In the Atlantic Ocean, the Sigma PFASs concentration decreased from 2007 to 2010. The elevated PFOA level that resulted from melting snow and ice in Greenland Sea implies that the Arctic may have been driven by climate change and turned to be a source of PFASs for the marine ecosystem. (c) 2012 Elsevier Ltd. All rights reserved.The global distribution and long-range transport of polyfluoroalkyl substances (PFASs) were investigated using seawater samples collected from the Greenland Sea, East Atlantic Ocean and the Southern Ocean in 2009-2010. Elevated levels of Sigma PFASs were detected in the North Atlantic Ocean with the concentrations ranging from 130 to 650 pg/L In the Greenland Sea, the Sigma PFASs concentrations ranged from 45 to 280 pg/L, and five most frequently detected compounds were perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS). PFOA (15 pg/L) and PFOS (25-45 pg/L) were occasionally found in the Southern Ocean. In the Atlantic Ocean, the Sigma PFASs concentration decreased from 2007 to 2010. The elevated PFOA level that resulted from melting snow and ice in Greenland Sea implies that the Arctic may have been driven by climate change and turned to be a source of PFASs for the marine ecosystem. (c) 2012 Elsevier Ltd. All rights reserved
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