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Effects of pollutant accumulation by the invasive weed saltcedar (Tamarix ramosissima) on the biological control agent Diorhabda elongata (Coleoptera: Chrysomelidae)
2009
Sorensen, Mary A. | Parker, David R. | Trumble, John T.
Hydroponic greenhouse studies were used to investigate the effect of four anthropogenic pollutants (perchlorate (ClO4-), selenium (Se), manganese (Mn), and hexavalent chromium (Cr (VI))) on the biological control agent Diorhabda elongata Brullé. Contaminant concentrations were quantified for experimental Tamarix ramosissima Ledab. plants and D. elongata beetles. Growth of larvae was significantly reduced by Se contamination, but was not affected by the presence of perchlorate, Mn, or Cr (VI). All of the contaminants were transferred from plants to D. elongata beetles. Only Cr (VI) was accumulated at greater levels in beetles than in their food. Because T. ramosissima grows in disturbed areas, acquires salts readily, and utilizes groundwater, this plant is likely to accumulate anthropogenic pollutants in contaminated areas. This study is one of the first to investigate the potential of an anthropogenic pollutant to influence a weed biological control system.
Mostrar más [+] Menos [-]Soil burdens of persistent organic pollutants – Their levels, fate and risk. Part II. Are there any trends in PCDD/F levels in mountain soils
2009
Kukučka, Petr | Klánová, Jana | Sáňka, Milan | Holoubek, Ivan
Good quality data apt for an assessment of temporal trends of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs) in soils are difficult to obtain since there is a general lack of information on their residues in soils. Variability of soil profiles, non-homogeneity of samples, and often also inconsistency of applied sampling procedures further complicate this problem. To assess spatial and temporal trends of contamination, three soil sampling campaigns have been performed over the period of 12 years at the mountain forest sites in the Czech Republic. Relation between the air, needle and soil contaminations was addressed in addition to time-related variability of soil. It has been confirmed that soil is a good matrix for evaluation of spatial distribution of persistent organic pollutants (POPs) but difficult for establishment of temporal trends. A slow rate of the soil-forming processes and their site-specificity was generally the major source of uncertainties. More than a decade of POP monitoring is recommended for successful establishment of temporal trends in forest soils.
Mostrar más [+] Menos [-]Vertical distribution of organochlorine pesticides in humus along Alpine altitudinal profiles in relation to ambiental parameters
2009
Kirchner, M. | Faus-Kessler, T. | Jakobi, G. | Levy, W. | Henkelmann, B. | Bernhöft, S. | Kotalik, J. | Zsolnay, A. | Bassan, R. | Belis, C. | Kräuchi, N. | Moche, W. | Simončič, P. | Uhl, M. | Weiss, P. | Schramm, K.W.
In forest soils along vertical profiles located in different parts of the Alps, concentrations of persistent organic pollutants (POPs), namely organochlorine pesticides (OCPs) like dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCH), heptachlor, aldrin, dieldrin and mirex, were measured. Though local characteristics of the sites are influenced by numerous factors like orographic and meteorological parameters, forest stand characteristics and humus parameters, we ascertained a marked vertical increase of concentrations of some organochlorine compounds in the soil. On the basis of climatological values of each site, we found that the contamination increase with altitude can be ascribed to a certain ‘cold condensation effect’. In addition, the perennial atmospheric deposition of POPs is controlled by precipitation. Other key parameters explaining the accumulation of POPs are the soil organic carbon stocks, the turnover times, the re-volatilisation and degradation processes, which vary with altitude. Caused by temperature-dependent processes regarding deposition, re-volatilization and decomposition of POPs, the concentration of organochlorine pesticides varies in the Alpine region with altitude.
Mostrar más [+] Menos [-]Progestagens for human use, exposure and hazard assessment for the aquatic environment
2009
Besse, Jean-Philippe | Garric, Jeanne
Little information is available on the environmental occurrence and ecotoxicological effects of pharmaceutical gestagens released in the aquatic environment. Since eighteen different gestagens were found to be used in France, preliminary exposure and hazard assessment were done. Predicted environmental concentrations (PECs) suggest that if parent gestagens are expected to be found in the ng l−1 range, some active metabolites could be present at higher concentrations, although limited data on metabolism and environmental fate limit the relevance of PECs. The biological effects are not expected to be restricted to progestagenic activity. Both anti-androgenic activity (mainly for cyproterone acetate, chlormadinone acetate and their metabolites) and estrogenic activity (mainly for reduced metabolites of levonorgestrel and norethisterone) should also occur. All these molecules are likely to have a cumulative effect among themselves or with other xenoestrogens. Studies on occurrence, toxicity and degradation time are therefore needed for several of these compounds. Gestagens exposure and hazard assessment for the aquatic environment.
Mostrar más [+] Menos [-]Waste recombinant DNA: Effectiveness of thermo-treatment to manage potential gene pollution
2009
Fu, Xiaohua | Li, Mengnan | Zheng, Guanghong | Le, Yiquan | Wang, Lei
Heating at 100 °C for 5-10 min is a common method for treating wastewater containing recombinant DNA in many bio-laboratories in China. In this experiment, plasmid pET-28b was used to investigate decay efficiency of waste recombinant DNA during thermo-treatment. The results showed that the decay half-life of the plasmid was 2.7-4.0 min during the thermo-treatment, and even heating for 30 min the plasmids still retained some transforming activity. Low pH promoted the decay of recombinant DNA, but NaCl, bovine serum albumin and EDTA, which existed in the most wastewater from bio-laboratories, protected DNA from degradation. Thus, the decay half-life of plasmid DNA may be longer than 2.7-4.0 min practically. These results suggest that the effectiveness of heating at 100 °C for treating waste recombinant DNA is low and a gene pollution risk remains when those thermo-treated recombinant DNAs are discharged into the environment. Therefore other simple and effective methods should be developed. Heating at 100 °C for 5-10 min to treat waste recombinant DNA has potential eco-risk.
Mostrar más [+] Menos [-]Bioaccumulation of organochlorine pollutants in the fish community in Lake Årungen, Norway
2009
Sharma, Chhatra Mani | Rosseland, Bjørn Olav | Almvik, Marit | Eklo, Ole Martin
Organochlorine pollutants in the major fish species (pike Esox lucius, perch Perca fluviatilis, and roach Rutilus rutilus) of Lake Årungen, Norway, were investigated after an extensive removal of large pike in 2004. The organochlorine pollutants detected in fish liver samples in 2005 were dichlorodiphenyltrichloroethane (DDTs), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and heptachlor epoxide (HCE). DDTs were the dominant among all analyzed OCs. ΣPCB and HCB, detected in fish from two clearly distinct trophic levels (prey and predators), give an indication of biomagnification. All OC concentrations in female pike were significantly lower compared to males, which might be due to the removal of high concentrations of pollutants in roe during spawning. Organochlorine pollutants in fish tissues tend to magnify up the food chain.
Mostrar más [+] Menos [-]Ultraviolet absorbance as a proxy for total dissolved mercury in streams
2009
Dittman, Jason A. | Shanley, James B. | Driscoll, Charles T. | Aiken, George R. | Chalmers, Ann T. | Towse, Janet E.
Stream water samples were collected over a range of hydrologic and seasonal conditions at three forested watersheds in the northeastern USA. Samples were analyzed for dissolved total mercury (THgd), DOC concentration and DOC composition, and UV₂₅₄ absorbance across the three sites over different seasons and flow conditions. Pooling data from all sites, we found a strong positive correlation of THgd to DOC (r² = 0.87), but progressively stronger correlations of THgd with the hydrophobic acid fraction (HPOA) of DOC (r² = 0.91) and with UV254 absorbance (r² = 0.92). The strength of the UV₂₅₄ absorbance-THgd relationship suggests that optical properties associated with dissolved organic matter may be excellent proxies for THgd concentration in these streams. Ease of sample collection and analysis, the potential application of in-situ optical sensors, and the possibility for intensive monitoring over the hydrograph make this an effective, inexpensive approach to estimate THgd flux in drainage waters. Ultraviolet absorbance measurements are a cost-effective proxy to estimate dissolved mercury concentration in stream water.
Mostrar más [+] Menos [-]The importance of ammonium mobility in nitrogen-impacted unfertilized grasslands: A critical reassessment
2009
Mian, Ishaq Ahmad | Riaz, Muhammad | Cresser, Malcolm S.
The physico-chemical absorption characteristics of ammonium-N for 10 soils from 5 profiles in York, UK, show its high potential mobility in N deposition-impacted, unfertilized, permanent grassland soils. Substantial proportions of ammonium-N inputs were retained in the solution phase, indicating that ammonium translocation plays an important role in the N cycling in, and losses from, such soils. This conclusion was further supported by measuring the ammonium-N leaching from intact plant/soil microcosms. The ammonium-N absorption characteristics apparently varied with soil pH, depth and soil texture. It was concluded for the most acid soils especially that ammonium-N leached from litter horizons could be seriously limiting the capacity of underlying soils to retain ammonium. Contrary to common opinion, more attention therefore needs to be paid to ammonium leaching and its potential role in biogeochemical N cycling in semi-natural soil systems subject to atmospheric pollution. mmonium mobility is more important than previously thought in N-impacted, unfertilized grasslands.
Mostrar más [+] Menos [-]Production and sedimentation of peptide toxins nodularin-R and microcystin-LR in the northern Baltic Sea
2009
Kankaanpää, Harri T. | Sjövall, Olli | Huttunen, Maija | Olin, Miikka | Karlsson, Krister | Hyvärinen, Kirsi | Sneitz, Laura | Härkönen, Janne | Sipiä, Vesa O. | Meriluoto, Jussi A.O.
This seven-year survey was primarily targeted to quantification of production of nodularin-R (NOD-R), a cyclic pentapeptide hepatotoxin, in Baltic Sea cyanobacteria waterblooms. Additionally, NOD-R and microcystin-LR (MC-LR; a cyclic heptapeptide toxin) sedimentation rates and NOD-R sediment storage were estimated. NOD-R production (70-2450 μg m⁻³; 1 kg km⁻² per season) and sedimentation rates (particles; 0.03-5.7 μg m⁻² d⁻¹; 0.3 kg km⁻² per season) were highly variable over space and time. Cell numbers of Nodularia spumigena did not correlate with NOD-R quantities. Dissolved NOD-R comprised 57-100% of total NOD-R in the predominantly senescent, low-intensity phytoplankton blooms and seston. Unprecedentedly intensive MC-LR sedimentation (0.56 μg m⁻² d⁻¹) occurred in 2004. Hepatotoxin sedimentation rates highly exceeded those of anthropogenic xenobiotics. NOD-R storage in surficial sediments was 0.4-20 μg kg⁻¹ (0.1 kg km⁻²). Loss of NOD-R within the chain consisting of phytoplankton, seston and soft sediments seemed very effective. Production of nodularin-R in pelagic Baltic Sea takes place in a scale of up to kilograms per square kilometre.
Mostrar más [+] Menos [-]Quantification of activated carbon contents in soils and sediments using chemothermal and wet oxidation methods
2009
Brändli, Rahel C. | Bergsli, Anders | Ghosh, Upal | Hartnik, Thomas | Breedveld, Gijs D. | Cornelissen, Gerard
Activated carbon (AC) strongly sorbs organic pollutants and can be used for remediation of soils and sediments. A method for AC quantification is essential to monitor AC (re)distribution. Since AC is black carbon (BC), two methods for BC quantification were tested for AC mixed in different soils and sediments: i) chemothermal oxidation (CTO) at a range of temperatures and ii) wet-chemical oxidation with a potassium dichromate/sulfuric acid solution. For three soils, the amount of AC was accurately determined by CTO at 375 °C. For two sediments, however, much of the AC disappeared during combustion at 375 °C, which could probably be explained by catalytic effects by sediment constituents. CTO at lower temperatures (325–350 °C) was a feasible alternative for one of the sediments. Wet oxidation effectively functioned for AC quantification in sediments, with almost complete AC recovery (81–92%) and low remaining amounts of native organic carbon (5–16%). Activated carbon quantification is best performed for soils with chemothermal oxidation at 375 °C, and for sediments with wet oxidation with potassium dichromate/sulfuric acid.
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