中空纤维膜萃取-液相色谱法测定印染废水中芳香胺

建立了一种中空纤维膜液相微萃取的样品前处理技术,结合液相色谱法测定印染废水中芳香胺,并且优化了萃取溶剂、供体相、接收相、搅拌速度、萃取时间等前处理条件.实验结果表明,以正辛醇为萃取溶剂,0.1 mol·L-1Na OH为供体相,0.1 mol·L-1HCl为接收相时,400 r·min-1作为搅拌速度,30 min萃取后的芳香胺富集倍数可达到101—193倍,萃取效率达20.2%—38.6%.结合液相色谱检测芳香胺的线性范围为0.01—0.25 mg·L-1,检出限为1.0—2.0μg·L-1,回收率为95.2%—105.2%.表明该方法可用于检测印染废水中的芳香胺类物质.     

温度驱动的离子液体分散液-液微萃取法同时检测环境水体中磺胺类药物

以l-辛基-3-甲基咪唑六氟磷酸离子液体([C8MIM][PF6])为萃取剂,利用温度驱动离子液体分散液-液微萃取技术,结合高效液相色谱(HPLC)同时测定环境水体中2种磺胺类化合物:磺胺间二甲氧嘧啶(sulfadimethoxine,SDM)和磺胺甲噁唑(sulfamethoxazole,SMZ).对影响萃取效果的一系列因素(萃取剂、分散剂、萃取剂和分散剂的体积、pH、温度、萃取时间、盐度和离心时间等)进行了优化,在最优条件下,该方法具有较宽的线性范围(2—200μg.L-1)、较低的检出限(SDM,1.22μg.L-1;SMZ,0.50μg.L-1)、良好的重现性(RSD:SDM,1.94%;SMZ,1.9%;n=7)和较高的准确性(回收率,SDM,88.7%;SMZ,101.3%;n=7).以该方法对几处环境水样进行测定,获得了良好的回收率(63.0%—124.0%;RSD:2.1%—4.9%;n=6).     

分散固相萃取-超高效液相色谱-串联质谱法测定城市污水中2种溴代阻燃剂

建立了分散固相萃取-超高效液相色谱-串联质谱法准确测定城市污水中六溴环十二烷(HBCD)和三-(2,3-二溴丙基)异氰脲酸酯(TBC)的方法.对萃取剂用量、萃取时间、淋洗剂、洗脱剂及色谱分离和质谱测定等条件进行了优化.优化后方法为:待测水样加入同位素标记的回收率内标,用0.4 g Silica、C18和HLB(1∶1∶1)混合填料分散固相萃取,回收萃取剂后用5 m L的10%的甲醇水溶液淋洗,8 m L甲醇洗脱,氮吹浓缩,加入同位素标记的进样内标测定.方法在1—200μg·L-1范围线性关系良好,HBCD和TBC的线性相关系数R20.9986,检出限为0.6—1.2 ng·L-1.应用该方法在某大型污水处理厂各工艺段污水中检测出了α-HBCD,浓度水平为1.3—5.4 ng·L-1.该方法操作简单、灵敏度高,尤其适合城市污水复杂基质中HBCD和TBC的分析.     

固相萃取-高效液相色谱法测定水中硝基苯含量

环境水中硝基苯主要来自染料、香料、炸药等有机合成工业废水.本文探讨了固相萃取-高效液相色谱法测定水中硝基苯的分析方法,方法在30.0μg·l-1-30mg·l-1范围内具有良好的线性关系(r=0.99984),回收率为89.5%-92.3%,RSD《1.5%,方法检出限为0.02μg·l-1.用本法测定污染水体中硝基苯的含量,结果令人满意.     

在线柱浓缩-液相色谱法测定水体中痕量敌草快和百草枯

采用在线柱浓缩-超快速液相色谱联用技术测定水体中痕量百草枯和敌草快.水样无需样品前处理,过滤后即可进样.采用固相萃取小柱富集待测物,以色谱梯度泵完成样品的净化后,利用阀切换技术将待测物反冲至分析柱进行分离,以二极管阵列检测器定量.方法在1.0—20.0μg.L-1范围内线性良好,百草枯和敌草快的线性相关系数分别为0.9997和0.9989.百草枯和敌草快的检出限(S/N=3)分别为0.10、0.12μg.L-1,加标回收率在96.0%—98.0%之间.用所建立的方法测定了水中痕量的百草枯与敌草快的含量,结果令人满意.     

高效液相色谱法测定水体中的阿特拉津

为建立检测水体中阿特拉津的高效液相色谱法,以ODSC18(250mm×4.6mm×5μm)柱为色谱柱,以甲醇∶水=5∶1为流动相,流速0.6mL·min-1,采用紫外检测器,用外标法测定水体中阿特拉津含量。结果表明,方法线性范围为0.052~13.0mg·L-1,线性相关系数r=0.9998;对浓度低于线性的样品,取100mL样品提取后测定,方法的检出限为0.0002mg·L-1,对含1.95μg·L-1、32.5μg·L-1、72.8μg·L-1阿特拉津水质样品进行测定,其相对标准偏差为1.61%-6.85%,加标回收率为84.6%~96.9%。采用净化方法时的加标回率为74.9%~92.9%。对阿特拉津含量在线性范围内的水样可直接过0.45μm膜后测定,加标回收率为97.0%~99.6%。该方法适用于水体中痕量和常量阿特拉津的测定。     

在线固相萃取-高效液相色谱法测定水中的苯脲化合物

通过在线固相萃取-高效液相色谱法快速、准确测定了EPA532方法规定的水中9种痕量苯脲化合物类杀虫剂.通过双梯度高效液相色谱系统中的上样泵,采用大体积自动进样方式,将2.5 mL水样中的被测物富集在萃取柱上;而后通过阀切换将萃取柱切换至分析流路中,进行分离、测定.上样泵的流动相为纯水和甲醇,分析泵的流动相为20 mmol·L-1甲酸铵水溶液和乙腈,流速分别为1.0 mL·min-1和0.6 mL·min-1,检测波长为245 nm,整个分析时间为20 min.方法在0.5—100μg·L-1范围线性关系良好,9种杀虫剂的线性相关系数R2≥0.9927,检出限≤0.093μg·L-1,7次平行测定保留时间RSD≤0.08%,峰面积RSD≤2.57%.该方法前处理简单,快速,重现性好,可用于环境水体和饮用水中痕量杀虫剂、除草剂等污染物的测定.     

基质固相分散-加压溶剂萃取法测定土壤中多环芳烃

建立基质固相分散(MSPD)辅助加压溶剂萃取(PLE)-高效液相色谱法测定土壤中16种多环芳烃的方法.土壤样品与弗罗里硅土混匀后装入萃取池,在15 MPa、120℃萃取条件下,丙酮∶二氯甲烷(1∶1,V∶V)作为萃取溶剂,静态提取5min,应用高效液相色谱法荧光检测-二极管阵列检测串联,采用外标法对其进行定量分析.结果表明:16种多环芳烃线性关系良好,相关系数均大于0.9994,利用荧光检测器与二极管阵列检测器的方法检出限分别为0.04—0.8μg·L-1、0.6—20μg·L-1,在低、中、高3个水平下的加标回收率在78.4%—105.8%范围内,测定结果的相对标准偏差为1.2%—4.1%(n=5).     

分散液液微萃取-超高效液相色谱-串联质谱法快速测定市售饮用水样中7种双酚-二环氧甘油醚

基于分散液液微萃取技术,以实际样品为研究对象,建立了饮用水中内分泌干扰物双酚A-二缩水甘油醚(BADGE)及其衍生物(BADGE·H_2O、BADGE·2H2O、BADGE·HCl、BADGE·2HCl、BADGE·H_2O·HCl)和双酚F-二缩水甘油醚(BFDGE)等7种双酚-二环氧甘油醚的分散液液微萃取-超高效液相色谱-串联质谱(DLLME-UPLC-MS/MS)检测方法.以三氯甲烷作为萃取剂(3.00 mL)、丙酮为分散剂(2.00 mL)制备分散液液微萃取系统,超声辅助萃取和浓缩样品中的双酚-二环氧甘油醚.含有0.01 mol·L~(-1)乙酸铵和1%甲酸的甲醇水溶液作为流动相,Waters SymmetryC_(18)分离后,电喷雾正离子(ESI+)模式串联四极杆质谱检测.7种双酚-二环氧甘油醚在5.0—1000.0μg·L~(-1)范围内线性关系良好,相关系数均大于0.9953;在50.00、100.00μg·L~(-1)和500.00μg·L~(-1)的3个添加水平下,7种目标化合物的平均回收率为79.9%—100.7%,相对标准偏差(RSD)均低于11.6%,检出限在0.5—5.0μg·L~(-1).该方法操作简单,灵敏度高,重复性好,能够在9 min内实现7种双酚-二环氧甘油醚的快速检测和定量分析.     

基于有序介孔碳涂层的固相微萃取法测定水中多环芳烃

采用溶剂挥发诱导自组装结合提拉法在不锈钢丝表面制备了以有序介孔碳(Ordered mesoporous carbon,OMC)为涂层的固相微萃取(Solid phrase microextraction,SPME)纤维,考察了该纤维的萃取效果和在高温下的稳定性,建立了水中多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)污染物的固相微萃取测定分析方法.扫描电镜(Scanning electron microscopy,SEM)结果表明,制备的OMC涂层连续完整且与不锈钢基体紧密结合,厚度约为11μm.氮吸附脱附结果证明,涂层材料具有规整的二维六方特征,孔径集中分布在3.8 nm,比表面积和孔容分别为522 m~2·g~(-1)和0.36 cm3·g~(-1).以水中多环芳烃类污染物作为分析对象,采用固相微萃取与气相色谱联用法探讨了OMC涂层对多环芳烃类污染物的萃取效果,对萃取方式、萃取时间、萃取温度、搅拌速度等条件进行了优化,并与商品化涂层进行了对比.结果表明,采用直接固相微萃取方式,萃取时间30 min,萃取温度50℃,搅拌速率800 r·min-1萃取效率最高;在最佳萃取条件下,OMC涂层分析5种PAHs的检测限范围是0.004—0.012μg·L~(-1),定量限范围0.010—0.025μg·L~(-1);萘和苊在0.1—250μg·L~(-1)范围内,芴、荧蒽和芘在0.25—100μg·L~(-1)范围内线性关系良好;单根纤维相对标准偏差(RSD)为3.9%—7.4%,多根纤维相对标准偏差为6.7%—9.8%.自制OMC纤维在350℃高温热解析80次后萃取效率不变,且对PAHs的萃取效率优于商用聚二甲基硅氧烷/二乙烯基苯(Polydimethylsiloxane/divinylbenzene,PDMS/DVB)涂层.将自制纤维应用于两种实际水样的固相微萃取分析中,分别添加0.25μg·L~(-1)和100μg·L~(-1)的样品回收率分别为81.3%—92.8%和89.3%—108.8%.     

Achieving Open Access to Conservation Science

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     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

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.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

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.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

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.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.