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Effects of prevalent freshwater chemical contaminants on in vitro growth of Escherichia coli and Klebsiella pneumoniae
2008
Higgins, J. | Hohn, C.
Many surface and ground waters in the continental US are contaminated with a variety of chemical pollutants, which are usually present in concentrations in the ppm and ppb range. The effects of these pollutants on coliform bacteria, which are prominent members of the aquatic flora, are poorly understood. Using a microtiter plate assay, isolates of Escherichia coli (from chicken intestine and fresh water), and an isolate of Klebsiella pneumoniae (from bovine milk) were exposed to varying concentrations of common pollutants over a 24 h period. The herbicides/pesticides simazine, atrazine, and diazinon; the VOCs trichloroethene and MTBE; the estrogens estradiol and estrone; and caffeine, all failed to inhibit bacterial growth at ppm levels. Only ethylene glycol, and the herbicide 2,4-D, significantly inhibited bacterial growth compared to controls. These results suggest that the replication of coliform bacteria in fresh waters is not adversely impacted by many common pollutants. Using a microtiter plate assay, E. coli and Klebsiella bacteria were exposed to a panel of common chemical pollutants of fresh water; only ethylene glycol and 2,4-D inhibited bacterial replication.
Afficher plus [+] Moins [-]Persistent organic pollutants in soils and sediments from James Ross Island, Antarctica
2008
Klánová, J. | Matykiewiczová, N. | Máčka, Z. | Prošek, P. | Láska, K. | Klán, P.
Soil and sediment samples from James Ross Island were analyzed for their PCB, OCP and PAH contents. Soil concentrations ranged between 0.51 and 1.82 ng g-1 for seven indicator PCB congeners, between 0.49 and 1.34 ng g-1 for HCH congeners, between 0.51 and 3.68 ng g-1 for the sum of p,p'-DDT, DDE, and DDD, and between 34.9 and 171 ng g-1 for the sum of 16 EPA PAHs. Sediment levels from 0.32 to 0.83 ng g-1 were found for PCBs, from 0.14 to 0.76 ng g-1 for HCHs, from 0.19 to 1.15 ng g-1 for DDTs, and from 1.4 to 205 ng g-1 for PAHs. A prevalence of low-mass PAHs, less chlorinated PCBs, and more volatile chemicals indicates that the long-range atmospheric transport from populated areas of Africa, South America, and Australia is the most probable contamination source for the solid matrices in James Ross Island. A survey of soil, sediment and air contamination in James Ross Island, Antarctica serves as a baseline study for evaluation of an anthropogenic impact of the new research facility.
Afficher plus [+] Moins [-]Kosetice, Czech Republic – ten years of air pollution monitoring and four years of evaluating the origin of persistent organic pollutants
2008
Dvorska, Alice | Lammel, Gerhard | Klánová, Jana | Holoubek, Ivan
The regional observatory Kosetice is a central European background station. Unique continuous monitoring from 1988 on is held here. POP (persistent organic pollutant) concentration values of air samples from Kosetice taken between 1996 and 2005 were statistically processed. Values of Czech ambient air quality standards were not exceeded. Concentrations of polycyclic aromatic hydrocarbons reached two maxima, in 1996 and 2001–2002. Polychlorinated biphenyls concentrations reached the highest values in 1997 and 1998 and hexachlorocyclohexanes concentrations in 1998. DDTs, hexachlorobenzene and pentachlorobenzene were analysed as well. Long-range transport of pollutants between 2002 and 2005 was evaluated using the Potential Source Contribution Function hybrid receptor model. Indicated potential source areas of PCBs coincide with many well-known urban and industrialised areas, while the indicated potential source areas of HCHs and DDTs coincide with many agricultural and/or forested regions and the potential source areas of HCB comprise all land use types. Source areas of organochlorinated pesticides used in agriculture are similar to each other, but different from the source areas of industrial polychlorinated biphenyls.
Afficher plus [+] Moins [-]Use of toxicity identification evaluations to determine the pesticide mitigation effectiveness of on-farm vegetated treatment systems
2008
Hunt, John | Anderson, Brian | Phillips, Bryn | Tjeerdema, Ron | Largay, Bryan | Beretti, Melanie | Bern, Amanda
Evidence of ecological impacts from pesticide runoff has prompted installation of vegetated treatment systems (VTS) along the central coast of California, USA. During five surveys of two on-farm VTS ponds, 88% of inlet and outlet water samples were toxic to Ceriodaphnia dubia. Toxicity identification evaluations (TIEs) indicated water toxicity was caused by diazinon at VTS-1, and chlorpyrifos at VTS-2. Diazinon levels in VTS-1 were variable, but high pulse inflow concentrations were reduced through dilution. At VTS-2, chlorpyrifos concentrations averaged 52% lower at the VTS outlet than at the inlet. Water concentrations of most other pesticides averaged 20–90% lower at VTS outlets. All VTS sediment samples were toxic to amphipods (Hyalella azteca). Sediment TIEs indicated toxicity was caused by cypermethrin and lambda-cyhalothrin at VTS-1, and chlorpyrifos and permethrin at VTS-2. As with water, sediment concentrations were lower at VTS outlets, indicating substantial reductions in farm runoff pesticide concentrations. Toxicity identification evaluations identified key pesticides in agricultural runoff, and their concentrations were reduced by farmer-installed vegetated treatment systems.
Afficher plus [+] Moins [-]Lysimeter Experiments to Investigate the Fate of Chemicals in Soils - Comparison of Five Different Lysimeter Systems
2008
Schroll, Reiner | Grundmann, Sabine | Dörfler, Ulrike | Rüth, Bernhard | Munch, Jean Charles
Several lysimeter scenarios and approaches exist to study the fate of agro-chemicals or contaminants from deposition in soil columns. In many systems just transport and leaching of the parent compound is followed, in some systems the leaching and transport of the metabolites is investigated as well. In more sophisticated lysimeter systems the volatilization and also the mineralization of the applied chemicals can be additionally monitored. Depending on the lysimeter system used and on the fact whether the applied chemicals are ¹⁴C-labeled or not, different results and various interpretations of the results might be achieved. Different lysimeter systems are described in this paper and a real dataset of a specific lysimeter experiment was transferred and evaluated in a virtual approach in the different lysimeter systems in order to show the advantages and disadvantages of the various systems.
Afficher plus [+] Moins [-]Are Pseudokirchneriella subcapitata and Chlorella vulgaris Affected by Environmental Samples from a Rice Field
2008
Marques, Catarina R. | Abrantes, Nelson | de Figueiredo, Daniela R. | Pereira, Mário J. | Gonçalves, Fernando
Rice fields represent important production rates in Portugal. However, the intensive soil management and the exploitation of agrochemicals may pose a threat to nontarget organisms. Hence, the present work regards the toxicity screening of surface waters and sediment elutriates collected during the drainage of fields in the vicinity of a rice paddy (Quinta do Seminário, Soure, Portugal): 1. in River Pranto (RP), the river from which the field irrigation water is canalized; 2. inside the rice paddy, from the main drainage channel - Vala de Enxugo (VE). For that purpose, it was used a combination of physico-chemical analyses and bioassays with two green algae species - Pseudokirchneriella subcapitata and Chlorella vulgaris. The chemical screening showed an apparent absence of xenobiotics in sediment samples, while no pesticides were found within the chemical contaminants detected in water samples. The nutrient load reflected low levels of inorganic contamination. Bioassays revealed that P. subcapitata was more sensitive to the overall physico-chemical conditions in natural samples than C. vulgaris, being its growth inhibited under water samples from both sites. On a whole, water samples, mainly those from the main irrigation/drainage channel of the rice fields (VE), were more deleterious to microalgae than those from RP or any of the elutriates.
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