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Fatal embryo chondral damage associated with fluoroquinolones in eggs of threatened avian scavengers 全文
2009
Lemus, J.Á | Blanco, G. | Arroyo, B. | Martinez, F. | Grande, J.
Stabled livestock reared in housed conditions are often subjected to intensive treatments with veterinary drug, which residues may be present in livestock meat ingested by scavengers, but nothing is known about their presence in eggs of wild birds and their potential detrimental effects on breeding success. We searched for residues of veterinary drugs and other toxicants in infertile and embryonated unhatched eggs of griffon vultures (Gyps fulvus) and red kites (Milvus milvus), two threatened avian scavengers. Quinolones (ciprofloxacin and enrofloxacin) were found in most unhatched eggs of both scavenger species clearly associated with severe alterations in the development of embryo cartilage and bones that could preclude embryo movements and subsequently normal development, pre-hatch position and successful hatching. The detrimental effects on developing eggs of veterinary drugs from livestock operations may help to explain reduced breeding success of avian scavengers. Fluoroquinolones used in livestock farming and found in eggs of avian scavenger caused severe alterations in embryo cartilage and bone development.
显示更多 [+] 显示较少 [-]Health risks from arsenic-contaminated soil in Flin Flon-Creighton, Canada: Integrating geostatistical simulation and dose-response model 全文
2009
Zhang, Hua | Huang, Guo-he | Zeng, Guang-ming
Elevated concentrations of arsenic were detected in surface soils adjacent to a smelting complex in northern Canada. We evaluated the cancer risks caused by exposure to arsenic in two communities through combining geostatistical simulation with demographic data and dose-response models in a framework. Distribution of arsenic was first estimated using geostatistical circulant-embedding simulation method. We then evaluated the exposures from inadvertent ingestion, inhalation and dermal contact. Risks of skin caner and three internal cancers were estimated at both grid scale and census-unit scale using parametric dose-response models. Results indicated that local residents could face non-negligible cancer risks (skin cancer and liver cancer mainly). Uncertainties of risk estimates were discussed from the aspects of arsenic concentrations, exposed population and dose-response model. Reducing uncertainties would require additional soil sampling, epidemic records as well as complementary studies on land use, demographic variation, outdoor activities and bioavailability of arsenic. Cancer risks induced by arsenic in soil were evaluated using geostatistical simulation and dose-response model.
显示更多 [+] 显示较少 [-]The study of operating variables in soil washing with EDTA 全文
2009
Zou, Zeli | Qiu, Rongliang | Zhang, Weihua | Dong, Hanying | Zhao, Zhihao | Zhang, Tao | Wei, Xiange | Cai, Xinde
This study discusses the operating variables for removal of metals from soils using EDTA, including the type of EDTA, reaction time, solution pH, dose, temperature, agitation, ultrasound and number of extractions. For As, Cd, Cu, Pb and Zn, the removal efficiency order was: H4-EDTA > Na2EDTA > (NH4)2EDTA. At low EDTA concentrations the removal increased progressively with increasing dose while above 0.4 mmol/g only small increases in extraction efficiency were observed. EDTA induced a two-step process including a rapid desorption within the first hour, and a gradual release in the following hours. The extraction efficiency of metals decreased with increasing pH in the range of 2-10. Consecutive extractions using low concentrations were more effective than a single extraction with concentrated EDTA if the same dose of EDTA was used. Consecutive extractions using low concentrations are more effective than a single extraction with concentrated EDTA if the same dose of EDTA is used.
显示更多 [+] 显示较少 [-]Toxicity of road salt to Nova Scotia amphibians 全文
2009
Collins, Sara J. | Russell, Ronald W.
The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands.
显示更多 [+] 显示较少 [-]Environmental pollution by antibiotics and by antibiotic resistance determinants 全文
2009
Martínez, José Luis
Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations. The article reviews the current knowledge on the effects that pollution by antibiotics and antibiotic resistance genes may have for the microbiosphere.
显示更多 [+] 显示较少 [-]Validation of the stomatal flux approach for the assessment of ozone visible injury in young forest trees. Results from the TOP (transboundary ozone pollution) experiment at Curno, Italy 全文
2009
Gerosa, G. | Marzuoli, R. | Desotgiu, R. | Bussotti, F. | Ballarin-Denti, A.
This paper summarises some of the main results of a two-year experiment carried out in an Open-Top Chambers facility in Northern Italy. Seedlings of Populus nigra, Fagus sylvatica, Quercus robur and Fraxinus excelsior have been subjected to different ozone treatments (charcoal-filtered and non-filtered air) and soil moisture regimes (irrigated and non-irrigated plots). Stomatal conductance models were applied and parameterised under South Alpine environmental conditions and stomatal ozone fluxes have been calculated. The flux-based approach provided a better performance than AOT40 in predicting the onset of foliar visible injuries. Critical flux levels, related to visible leaf injury, are proposed for P. nigra and F. sylvatica (ranging between 30 and 33 mmol O3 m-²). Soil water stress delayed visible injury appearance and development by limiting ozone uptake. Data from charcoal-filtered treatments suggest the existence of an hourly flux threshold, below which may occur a complete ozone detoxification. The stomatal uptake of ozone is an important factor to evaluate visible injury appearance and evolution in plants.
显示更多 [+] 显示较少 [-]Genotoxic effect of polycyclic aromatic hydrocarbons in the metropolitan area of Porto Alegre, Brazil, evaluated by Helix aspersa (Müller, 1774) 全文
2009
Ianistcki, M. | Dallarosa, J. | Sauer, C. | Teixeira, C.E. | Silva, J Da
The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM10-2.5 and PM<2.5). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM<2.5) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions. DNA damage in H. aspersa exposed to atmospheric particulate in Metropolitan Area of Porto Alegre demonstrated association with PAHs in the fine filter (PM<2.5).
显示更多 [+] 显示较少 [-]Effects of chronic elevated ozone exposure on gas exchange responses of adult beech trees (Fagus sylvatica) as related to the within-canopy light gradient 全文
2009
Kitao, Mitsutoshi | Löw, Markus | Heerdt, Christian | Grams, Thorsten E.E. | Haberle, Karl-Heinz | Matyssek, Rainer
The effects of elevated O3 on photosynthetic properties in adult beech trees (Fagus sylvatica) were investigated in relation to leaf mass per area as a measure of the gradually changing, within-canopy light availability. Leaves under elevated O3 showed decreased stomatal conductance at unchanged carboxylation capacity of Rubisco, which was consistent with enhanced δ13C of leaf organic matter, regardless of the light environment during growth. In parallel, increased energy demand for O3 detoxification and repair was suggested under elevated O3 owing to enhanced dark respiration. Only in shade-grown leaves, light-limited photosynthesis was reduced under elevated O3, this effect being accompanied by lowered Fv/Fm. These results suggest that chronic O3 exposure primarily caused stomatal closure to adult beech trees in the field regardless of the within-canopy light gradient. However, light limitation apparently raised the O3 sensitivity of photosynthesis and accelerated senescence in shade leaves.
显示更多 [+] 显示较少 [-]Genotoxicity of water from the Songhua River, China, in 1994-1995 and 2002-2003: Potential risks for human health 全文
2009
Liu, Jia-Ren | Dong, Hong-Wei | Tang, Xuan-Le | Sun, Xiang-Rong | Han, Xiao-Hui | Chen, Bing-Qing | Sun, Chang-Hao | Yang, Bao-Feng
A previous study showed that the cancer mortalities are higher for residents who lived nearby the Songhua River heavily polluted by organic contamination. It is important to determine its risk of carcinogenic potential. Short-term genotoxic bio-assays using Salmonella, Sister Chromatid Exchange (SCE), and Micronuclei (MN) assays were employed to examine the genotoxic activity of ether extracts of water samples taken from the Songhua River. The results of the Salmonella bioassay indicated that there were indirect frame-shift mutagens in the water samples. A dose-response relationship for the SCE and MN assays was obtained. These results showed that organic extracts of water samples have genotoxic activity and the risk of carcinogenic potential to human health. The mutagenesis of water samples had changed compared to the results in 1994-1995. An increasing trend of risk of carcinogenic potential in the Songhua River after ten years should be noted and needs to be studied further.
显示更多 [+] 显示较少 [-]Effects of pollutant accumulation by the invasive weed saltcedar (Tamarix ramosissima) on the biological control agent Diorhabda elongata (Coleoptera: Chrysomelidae) 全文
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.
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