首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
添加物对填埋场稳定化时间的影响   总被引:8,自引:0,他引:8  
在垃圾中添加KCl、KH2PO4、(NH4)2CO3,FeCl2时,对垃圾降解和填埋场稳定化时间的缩短有促进作用,而CuSO4、K2C42O7、Na2MoO4、Na2WO4、醋酸的加入则抑制了垃圾的降解,认为KCl是促进垃圾降解,加速填埋场稳定化的最佳添加物。  相似文献   

2.
雨水中S(Ⅳ)的离子色谱分析及其保护方法的研究   总被引:3,自引:1,他引:3  
栗欣  郭花捷 《环境化学》1996,15(1):76-81
本文研究了用离子色谱法分析雨水中S(Ⅳ)的色谱条件和含S(Ⅳ)样品的保存方法,采用HPIC_ASA分离柱、用2mmol.l^-1Na2CO3/3mmol.l^01NaOH溶液作淋洗液、0.0125mol.l^-1H2SO4为再生液、电导检测的方法,具有无干扰和灵敏度高等优点,而且在S(Ⅵ)的浓度秋-28μg.ml^-1范围内,其浓度与响应值之间呈现出良好的线性关系,其线性相关系数在0.9995以上  相似文献   

3.
对Al2(SO4)3,Ca(OH)2不同反应条件下去除洗涤废水中总磷的情况作了对比试验,结果表明,按Ca(OH)2:TP=3.7:1.0(重量比)投加试剂,回用生成的磷灰石沉淀助凝,TP(总磷)去除率可达95%,CODcr有少量去除。  相似文献   

4.
硅营养缓解水稻幼苗Cd、Cr毒害的生理研究   总被引:58,自引:0,他引:58  
两系法杂交稻“培杂山青”和常规稻“双桂36”幼苗经较高浓度的Cd2+(c=9.6~38.4μmol/L)或Cr3+(c=7.5~25.0μmol/L)处理可使其叶片光合速率、叶绿素(a+b)含量、叶绿素a/b比值、叶片可溶性糖、淀粉及可溶性蛋白质含量降低,而叶片的POD活性提高;低浓度Cd2+(c=4.8μmol/L)和Cr3+(c=2.5μmol/L)处理幼苗对上述生理指标有提高作用,但POD活性稍降低.加Si(Na2SiO3)[c(SiO2)=1.331mmol/L]的Cd、Cr处理比不加Si的Cd、Cr处理的幼苗叶片上述生理指标明显提高,且明显降低其POD活性.说明Si在不同程度上起到缓解Cd、Cr对水稻幼苗的毒害作用.而c(Cr3+)=25.0μmol/L是“双桂36”幼苗的致死浓度  相似文献   

5.
煤的化学脱硫研究   总被引:3,自引:1,他引:3  
高子群  胡旭东 《环境化学》1994,13(6):486-491
以我国的三种高硫煤-山东兖州、四川南楠、东林煤为试验煤样,考察了Fe2(SO4)3溶液和NaOH溶液加热处理的脱硫作用,以及热解时煤中有机硫的变化。试验发现,用2mol/lFe2(SO4)3在反应温度100℃,反应时间4h下,可脱除近80%的硫铁矿硫;经6%NaOH溶液处理后再用5%HCl浸煮,即可有效脱除煤中矿物质,也能明显脱硫;在煤热解时,煤中有机硫大部分滞留于煤焦中,被脱除的硫主要以H2S形  相似文献   

6.
研究红壤对SO4(2-)和H_2PO(4-)的吸附与竞争吸附机理.实验结果表明,红壤吸附H2PO4-的量远远大于SO4(2-),前者几乎是后者的2倍.在两种阴离子共存体系中,H2PO4-使SO4(2-)吸附量明显减少,在浓度低时甚至出现负吸附;SO4(2-)对H2PO4-吸附量的影响很小.说明土壤对H2PO4-的吸持力较强,为高强度专性吸附,不易于被其它阴离子解吸;土壤对SO4(2-)的吸持力则较弱,为低强度专性吸附或非专性物理吸附,能够被吸持力更强的阴离子完全解吸.  相似文献   

7.
福建省沿海地区海盐和大气污染物反应的致酸作用   总被引:4,自引:0,他引:4  
姚小红  崔平 《环境化学》1998,17(4):320-325
本文着重研究福建省沿海地区盐和大气污染物反应的致酸作用,从源排放估算、致酸前体物观测、大气气溶胶组成分析、降水离子特征分析四个层次进行讨论,结果表明HCl人为排放源仅占SO2,NOs的4%;大气中活性氯;HCl最大浓度为4.23μg/m^-3,Cl2最大浓度为3.97μg.m^-3,气溶胶中Cl^-/Na^+比和降水中Cl/Na^+比背离,降水中过量氯与H浓度呈现正相关,过量氯对H浓度最大贡献达3  相似文献   

8.
H2O2对抗旱性不同玉米品种愈伤组织抗氧化系统的影响   总被引:1,自引:0,他引:1  
两个玉米品种愈伤组织经10-4molL-1、10-3molL-1和10-2molL-1H2O2处理3h后,电解质泄漏率加大;H2O2和MDA含量增加;AsA和CAR含量的减少.10-4molL-1的H2O2处理对愈伤组织产生的氧化伤害较小.抗旱性较强品种PAN6043愈伤组织的抗氧化酶(SOD、POD、AP和GR)活性高于抗旱性较弱品种SC701,AsA和CAR含量的下降程度低于SC701.PAN6043愈伤组织具有较强的抗H2O2能力,与含高活力抗氧化系统密切相关  相似文献   

9.
链霉菌碱性脂肪酶的研究   总被引:1,自引:0,他引:1  
从杭州土壤中获得的一支链霉菌,通过UV、DES和Co60 - γ射线的5 代诱变,选育成功了高产的Z94- 2 菌株,经过对Z94 -2 的发酵研究,产碱性脂肪酶活力达596 umL,其最适培养基(λu L-1) 为:糊精10、黄豆饼粉30、尿素10 、K2HPO40 .5、MgSO4·7H2O0 .5、NaCl1 和AEO9 0.5 ,产酶的最适条件为:初始pH9.0~10.0 ,26℃培养48 h.对Z94- 2 与其他菌株的碱性脂肪酶的特性作了比较  相似文献   

10.
OH自由基引发的甲烷光化学氧化体系中有机过氧化物的研究   总被引:11,自引:0,他引:11  
齐斌  陈忠明 《环境化学》1998,17(4):309-314
在1.01325×10^5Pa,298K,O2-N2气氛下,采用长光路付立叶红外光谱仪跟踪反应进程,高压液相色谱仪测定反应产物中有机过氧化物,研究了OH自由基基引发的甲烷光化学反应体系,证实反应产物中有H2O2、甲基过氧化氢(CH3O2H,MHP)和过氧甲醚(CH3O2CH3),并发现羟甲基过氧化氢(HOCH2OOH,HMHP)和一未知有机过氧化物,HMHP的发现表明CH4氧化过程中可能存在过氧甲  相似文献   

11.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

12.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

13.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

14.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

17.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

18.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

19.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

20.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号