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941.
Respiration induced by substrate and bacteria diversity after application of diuron,hexazinone, and sulfometuron-methyl alone and in mixture 总被引:1,自引:0,他引:1
Fabrícia Cristina Dos Reis Valdemar Luiz Tornisielo Bianca A. B. Martins Adijailton José de Souza Pedro Avelino Maia De Andrade Fernando Dini Andreote 《Journal of environmental science and health. Part. B》2013,48(7):560-568
AbstractAfter application, herbicides often reach the soil and affect non-target soil microorganisms, decreasing their population, diversity or affecting metabolic activity. Therefore, laboratory studies were performed to evaluate the effects of diuron, hexazinone and sulfometuron-methyl alone and mixed upon carbon transformation by soil microorganisms in clayey and sandy soils and the effect on bacterial diversity and structure. Control treatment without herbicide application was also performed. Sub-samples from the control and herbicide treatments (10?g – in triplicate) were collected before herbicide application and 7, 14, 28 and 42?days after treatment (DAT), then 1?mL of 14C-glucose solution was applied. The released 14CO2 was trapped in 2?M NaOH solution and the radioactivity was analyzed by liquid scintillation counting (LSC), 12?h after glucose application. The effect of herbicides on bacterial diversity was evaluated by T-RFLP. The experiment was conducted in a complete randomized design. Hexazinone did not affect 14CO2 evolution. Diuron showed a greater 14CO2 evolution in sandy and clayey soil, while sulfometuron-methyl led to an increase in sandy soil, at 42 DAT. A greater evolution of carbon was observed in the treatment with herbicide mixture in sandy soil, compared with the same treatment in clayey soil or control. However, the herbicide mixture application did not affect the soil biological activity measured by the respiration rate induced by substrate. On the other hand, the herbicide mixtures affected the bacterial diversity in both soils, being the strongest effect to diuron and sulfometuron-methyl in clayey soil and hexazinone in sandy soil. 相似文献
942.
Bulent Kabak Esther F. A. Brandon Isil Var Marco Blokland Adrienne J. A. M. Sips 《Journal of environmental science and health. Part. B》2013,48(5):472-480
In the present study, we aimed at determining the release of aflatoxin B1 (AFB1) and ochratoxin A (OTA) from different food products in the gastro-intestinal tract in the absence and presence of probiotics, a possible adsorbent. The average bioaccessibility of AFB1 and OTA without probiotics was about 90%, and 30%, respectively, depending on several factors, such as food product, contamination level, compound and type of contamination (spiked versus naturally contaminated). The six probiotic bacteria showed varying binding capacity to AFB1 and OTA depending on the bacterial strain, toxin studied, type of food and contamination level. A reduction to a maximum of 37% and 73% as observed for the bioaccessibility of AFB1 and OTA in the presence of probiotic bacteria, respectively. This is the first report on the effect of probiotic bacteria on reducing the fraction of mycotoxins available for absorption in the gastrointestinal tract from different food products. 相似文献
943.
丝状菌对生物淋滤去除底泥中重金属的促进作用 总被引:1,自引:1,他引:0
利用氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)对采自株洲霞湾港底泥中的Cu、Cd、Pb和Zn 4种重金属进行生物淋滤实验,在实验中加入丝状菌考察其对重金属去除效果的影响。结果表明,丝状菌可以有效抑制低分子量有机酸对A.f的毒害作用,促进各种重金属的去除。当加入10%(体积比)的丝状菌后,生物淋滤过程中系统pH值在5 d内降低到2以下,Fe2+在4 d内完全氧化。经过10 d的处理,Cu、Cd、Pb和Zn 4种重金属的最高去除率分别达到76.3%、92.5%、52.6%和88.5%,与不加入丝状菌的处理相比,达到最大去除率所需的时间缩短1~2 d,4种重金属中,丝状菌的加入对Pb的去除促进作用最为明显,其去除率增加1倍左右。因此,在生物淋滤处理重金属-有机物复合污染底泥工艺中接入丝状菌对处理效果有很好的促进作用。 相似文献
944.
R. N. Ferebee R. K. Guthrie 《Journal of the American Water Resources Association》1973,9(6):1125-1135
ABSTRACT: Heterotrophic, mesophilic bacteria derived from, and maintained in, a freshwater environment were subjected to three classes of herbicides. Diuron, 2,4,5-Trichlorophenoxyacetic acid, and paraquat, used as water soluble solutions, were added (0.7 and 1.4 mgA) to a laboratory culture of bacteria. Total numbers of the bacteria, representing several genera, were monitored for alteration of numbers and types. Temperature, pH, and dissolved oxygen were monitored and the culture medium was tested for residual herbicide. Alterations observed in populations were considered to result from herbicide additions. Each herbicide tested was found to affect bacterial populations differently. Reasons for observed differences are discussed. In this aquatic environment the herbicides remained qualitatively measurable for periods up to three weeks. 相似文献
945.
Ure A. Anugwelem Rufits K. Guthrie Ernst M. Davis 《Journal of the American Water Resources Association》1981,17(6):1000-1004
ABSTRACT: Escherichia coli, Streptococcus faecalis, Salmonella typhimurium, and Staphylococcus aureus were tested by plate counts and Warburg respirometry to determine effects of the presence of carbaryl in water. E. coli and S. typhimurium were initially stimulated in the presence of the insecticide whereas S. faecalis and S. aureus were inhibited. Over a period of days, all bacteria died off more rapidly in the presence of carbaryl. The implications of these data in regards to bacteriological testing of water quality are discussed. 相似文献
946.
Roger L. Kaesler Edwin E. Herricks 《Journal of the American Water Resources Association》1979,15(4):1117-1125
ABSTRACT: Hierarchical diversity analysis of data on fish and aquatic insects showed that the component of diversity contributed by the species level was generally very small compared with the component at the generic level or with the total diversity. Very high rank correlations between generic diversity, in which genera were discriminated but not identified, and species diversity suggested that the purposes of environmental monitoring might best be served by working at the generic level rather than the species level. This is particularly true when an index of diversity is to be used as the major comparative and communicative tool. The savings of time and money could be appreciable. 相似文献
947.
948.
949.
Luanne Y. Steffy Angela L. McGinty Claire Welty Susan S. Kilham 《Journal of the American Water Resources Association》2004,40(5):1269-1275
ABSTRACT: Valley Creek watershed is a small stream system that feeds the Schuylkill River near Philadelphia, Pennsylvania. The watershed is highly urbanized, including over 17 percent impervious surface cover (ISC) by area. Imperviousness in a watershed has been linked to fish community structure and integrity. Generally, above 10 to 12 percent ISC there is marked decline in fish assemblages with fish being absent above 25 percent ISC. This study quantifies the importance of ground water in maintaining fish species diversity in subbasins with over 30 percent ISC. Valley Creek contains an atypical fish assemblage in that the majority of the fish are warm‐water species, and the stream supports naturally reproducing brown trout, which were introduced and stocked from the early 1900s to 1985. Fish communities were quantified at 13 stations throughout the watershed, and Simpson's species diversity index was calculated. One hundred and nine springs were located, and their flow rates measured. A cross covariance analysis between Simpson's species diversity index and spring flow rates upstream of fish stations was performed to quantify the spatial correlation between these two variables. The correlation was found to be highest at lag distances up to about 400 m and drop off significantly beyond lag distances of about 800 m. 相似文献
950.
California and other regions in the United States are becoming more populated and ethnically diverse, and thus, ecological
impacts on the wildland–urban interface are a significant policy concern. In a socioeconomic assessment focused on the geographic
regions surrounding four national forests in southern California, population projections are being formulated to assist in
the update of forest plans. In southern California, the projected trend of explosive population growth combined with increased
ethnic and racial diversity indicates four challenges for environmental management. First, patterns of recreation use on wildlands
are likely to change, and management of these areas will have to address new needs. Second, as land-management agencies face
changing constituencies, new methods of soliciting public involvement from ethnic and racial groups will be necessary. Third,
growth in the region is likely to encroach upon wildland areas, affecting water, air, open space, and endangered species.
Fourth, in order to address all these concerns in a climate of declining budgets, resource management agencies need to strengthen
collaborative relationships with other agencies in the region. How environmental managers approach these changes has widespread
implications for the ecological sustainability of forests in southern California. 相似文献