3种典型有机氯农药对锦鲤幼鱼的雌激素效应及其体内富集

为研究3种典型有机氯农药(%-六六六、p,p'-DDT和七氯)低浓度暴露对锦鲤幼鱼的雌激素效应及其体内富集效应,将锦鲤幼鱼暴露于有机氯农药的6个浓度组中进行20 d慢性毒性试验,测量血清中游离钙和蛋白结合磷含量及体内各组织有机氯农药残留。结果表明,在低浓度暴露20 d后,锦鲤幼鱼血清中游离钙和蛋白结合磷含量均随暴露浓度增加而呈先增后减之势,产生了明显的雌激素效应。p,p'-DDT在鱼体各组织中的富集能力远高于%-六六六和七氯;p,p'-DDT主要在鱼油中富集,其次为鱼肝、鱼鳃和鱼皮;%-六六六和七氯主要在鱼肝中富集,其次为鱼皮、鱼鳃和鱼油;3种有机氯农药在鱼肉中的富集相对较少。     

有机氯农药在太湖水体-沉积物中的交换特征

有机氯农药(OCPs)是一类重要的持久性有机污染物(POPs),具有半挥发性、持久性和高毒性,并能通过食物链富集,危害生态系统和人体健康。有机氯农药可以在不同的环境介质间迁移,并能在大气环境中进行远程输送,导致大范围乃至全球性的环境污染。最近的研究发现太湖地区的有机氯农药含量仍然非常高,为了了解太湖有机氯农药的来源以及环境行为,采用气相色谱质谱法对太湖竺山湾水体和沉积物样品中有机氯农药(OCPs)含量进行了测定,探讨了太湖水体和沉积物中有机氯农药的可能来源以及水体-沉积物之间的交换通量。研究结果表明:沉积物样品中的六氯苯的含量最高,为2.33ng·g-1(干质量,下同),其次为p,p’-DDT、p,p’-DDE和β-HCH,含量分别为0.67、0.64和0.37 ng·g-1。从水体中OCPs的组成来看,p,p’-DDT的含量最高为426.26 pg·L-1,其次是α-HCH和硫丹Ⅰ,含量分别为289.99和215.20 pg·L-1。采用α-HCH/γ-HCH比值对HCHs的来源进行分析,发现太湖水体中的γ-HCH污染来源于工业品六六六和林丹的使用,由交换模型得出HCHs的净交换通量为释放通量,表明HCHs的迁移方向是由沉积物到水中,沉积物的释放已成为太湖水体中HCHs的主要来源之一。水体中的p,p’-DDT/p,p’-DDE比值远大于1,而且由交换模型得出p,p’-DDT的净交换通量为沉降通量,说明了近期可能有新的污染源的输入。值得注意的是,硫丹Ⅰ的净交换通量同样为沉降通量,反映出太湖水体中硫丹Ⅰ可能存在新源的输入。     

环境雌激素o,p′-DDT和抗雌激素氟维司群对斑马鱼胚胎的复合效应

为探究雌激素与抗雌激素的复合效应,将斑马鱼(Danio rerio)的胚胎暴露于o,p′-DDT和氟维司群2种典型的环境内分泌干扰物中,考察胚胎孵化率、孵化时间和总畸形率,并用实时荧光定量PCR技术检测Vtg1、Vtg2和ERα等雌激素效应相关基因的mRNA转录水平.结果显示,与单一化合物的暴露相比,o,p′-DDT和...     

珠江三角洲地区大气中有机氯农药的被动采样观测

利用PUF被动采样装置,对珠江三角洲地区大气中有机氯农药(OCPs)进行监测.结果显示,广东省大气中有机氯农药主要是滴滴涕(DDTs)、六六六(HCH)及氯丹(Chlordane),其中DDTs约占总OCPs的54.5%;香港大气中农药残留主要是氯丹和DDTs,氯丹约占总含量的51.3%.珠三角地区大气中有机氯农药空间分布差异明显(580-5500pg·m-3),香港平均浓度远远低于广东省.另外,广东省仍有工业DDT在使用,造成广东省大气中有"新"的工业DDT输入;而三氯杀螨醇是香港大气中DDT高含量的重要来源;广东省和香港HCH主要源于林丹使用的残留,香港的Eastern及Tsuen Wan源于工业六六六使用的残留;珠江三角洲所有采样点的HCB含量较低,大气中HCB少量残留可能是HCB作为药物中间体的化学合成及HCB在大气中长距离传输的结果.     

厌氧滤池-膜生物反应器处理垃圾渗滤液不同工艺段中有机氯农药残留的分析

建立了基于HLB固相萃取柱和气相色谱／电子捕获(GC／ECD)分析垃圾渗滤液中有机氯农药的分析方法,对厌氧滤池．膜生物反应器处理垃圾渗滤液不同工艺段水体中有机氯农药的浓度进行了分析．结果表明,应用厌氧滤池．膜生物反应器处理垃圾渗滤液可以有效去除有机氯农药残留,主要去除工艺是厌氧,其中P,P’-DDT厌氧反应的中间体产物是P,P’-DDD,大部分继续转化为其它产物．在所试验的垃圾渗滤液中没有检出DDTs和HCHs以外的其它优先控制有机氯农药．     

滴滴涕类农药在广东省沿海地区水产品中的残留及人体暴露水平

水产品的摄入是人体暴露于有机氯农药的主要途径之一.实验检测了采自广东省11个沿海城市水产市场的海鲜类水产品(包括6种虾类、2种蟹类和13种贝类共228个样品)中滴滴涕类农药(包括o,p’-DDT、p,p’-DDT、o,p’-DDD、p,p’-DDD、o,p’-DDE和p,p’-DDE)的残留.结果显示,DDTs在虾类、蟹类和贝类体内的平均湿重含量范围分别为0.8￣17.6ng·g-1、5.1￣16.0ng·g-1和0.6￣209.4ng·g-1.不同水产品之间因生活环境和生活习性的不同,导致其DDTs含量存在较大差别.与我国最新的食品残留标准(GB2763-2005)相比,所检测样品DDTs的含量均未超标.但若以美国环境保护局(USEPA)的标准来衡量,则DDTs含量超标的百分率达27.6%.据最近的膳食结构调查显示,广东省沿海地区的居民每天虾、蟹、贝类水产品的平均消费量为26.0g,因而通过海鲜类水产品每天摄入DDTs的量为2.4ng·kgbodyweight-1·day-1,这一结果远远低于我国设定的每日耐受摄入量(PTDI)和联合国粮农组织及世界卫生组织(FAO/WHO)的相关标准.     

苏南典型土壤中22种有机氯农药的垂直分布特征

近10年来,大批农药、化工企业迁出江苏南部地区,为了解该地区有机氯农药的残留状况以及环境行为,首次对南京、镇江、常州、无锡、苏州部分农业区和工业区浅层土壤中22种有机氯农药(OCPs)的分布特征进行研究,采用加速溶剂萃取法(ASE)和气相色谱法(GC-ECD),对30个不同深度样品进行检测。结果表明:表层土壤依旧是OCPs的主要残留层,主要为滴滴涕(DDTs)和六六六(HCHs)类污染,其中,ω(DDTs)为ND~313.0 ng·g-1(干重,下同),平均值75.04ng·g-1;ω(HCHs)为ND~9.25 ng·g-1,平均值2.82 ng·g-1。DDTs残留以降解代谢产物p,p′-DDD和p,p’-DDE为主,HCHs残留则以β-HCH为主。此外,六氯苯(HCB)、艾氏剂(Aldrin)、七氯(Heptachlor)、狄氏剂(Dieldrin)和硫酸硫丹(Endosulfan sulfate)也有不同程度检出。不同利用类型表层土壤中,有机氯残留状况有所差异,DDTs在工业区土壤中残留量最高,而HCHs在农业区土壤中残留量最高,OCPs残留平均值为工业区(127.2 ng·g-1)农业区(30.75 ng·g-1)。垂向土壤样品分析结果表明:大部分点位OCPs、DDTs及HCHs的残留量均随土壤深度增加而降低,但在下降过程中存在一定的波动性,由于场地土壤受到人为活动的影响,存在一定的干扰现象。本次调查未检出γ-HCH,仅有少量α-HCH检出,说明这些地区近期未出现林丹和HCHs输入。样品中(p,p′-DDD+p,p′-DDE)/DDTs的比值显示该地区近期新的外源DDTs输入较少。本次调查提供的数据可为该地区OCPs垂直分布研究提供参考。     

北京市郊再生水灌区土壤有机氯农药垂向分布特征

在北京市郊再生水灌区采用正三角型布点法进行了3个钻孔的采样工作,钻孔间隔为1m,从表层开始每隔0.5m取一个样,3个钻孔共36组样品,同时采集钻孔附近的灌溉水及地下水,分别测试了土壤的理化参数及其土壤、灌溉水及地下水中9种有机氯农药的质量分数。测试结果表明：表层土壤是有机氯农药的主要残留层,表层土壤中检出的DDTs和BHCs质量分数较高,分别为2814.21ng·kg^-1和1130.41ng·kg^-1,但均符合土壤环境质量一级标准,残留污染程度较轻;其他层位以七氯和艾氏剂为主要检出物,最高质量分数分别为1286.19ng·kg^-1和781.23ng·kg^-1;其中艾氏剂未在表层土壤中检出;灌区内未检出的γ-BHC和（DDE＋DDD）/DDT的计算值为1.80,都说明近期内没有新污染源的输入;检出的有机氯农药在土壤剖面上的迁移能力有HEP〉ALD〉BHCs〉DDTs〉HCB,与地下水中检出的规律一致。     

北江清远段有机氯农药的污染特征与风险评估

北江作为清远市居民的主要生活饮用水水源,水体中持久性有机污染物污染问题备受重视,但目前对于北江清远段水体中酞酸酯的研究较少。了解OCPs的分布、来源及健康、生态风险,对于保障北江清远段居民的饮用水安全,给北江水生态环境保护管理提供技术支持具有重要参考意义。2016年7月和12月于北江清远段采集40个水和表层沉积物样品,采用高分辨气相色谱-高分辨质谱联用仪(HRGC-HRMS)法测定了样品中的有机氯农药(Organochlorine Pesticides,OCPs),分析了北江清远段水环境中OCPs的残留特征,并进行了健康和生态风险评估。结果表明,北江清远段水和沉积物中OCPs的残留较少,检出率低。丰枯两季水中仅有异狄氏剂(Endrin)和六氯苯(HCB)2种化合物被检出,丰水期水中ΣOCPs质量浓度为0.25-12 ng·L~(-1),枯水期水中ΣOCPs质量浓度为nd(表示未检出)-3.29 ng·L~(-1);沉积物中5种目标化合物:HCB、六六六(γ-HCH)、狄氏剂(Dieldrin)、滴滴伊(p,p’-DDE)、滴滴涕(o,p’-DDT)被检出,丰水期沉积物中∑OCPs质量分数为0.14-5.58ng·g~(-1),枯水期沉积物中∑OCPs质量分数为0.02-2.16ng·g~(-1)。OCPs的污染源解析结果表明,沉积物中DDT为历史残留导致,γ-HCH来源于杀虫剂林丹。致癌风险和非致癌风险评价结果表明,北江清远段水中OCPs对人体均未达到致癌风险。采用淡水沉积物环境质量基准法和效应区间中低值法评价沉积物中OCPs生态风险,发现丰水期BJ-1、BJ-4、BJ-6采样点对水生动物产生不良反应。     

酵母双杂交技术构建重组人雌激素受体基因酵母

应用酵母双杂交技术构建重组人雌激素受体基因酵母,用以检测类/抗雌激素化合物和环境样品的类/抗雌激素活性.采用多聚酶链反应(PCR)法扩增人雌激素受体(hER)基因,构建诱饵质粒pGBKT7-ER LBD;分别提取并纯化两种含有ER共激活因子基因的靶质粒pGAD424-GRIP1和pGAD424-SRC1;诱饵质粒和靶质粒同时转染酵母细胞Y187,于营养缺陷型培养基(SD/-Trp/-Leu)上筛选阳性菌落,分别构建两种ER双杂交酵母ER+GRIP1和ER+SRC1.考察双杂交酵母与不同激素:17β-雌二醇(E2)、二氢睾酮(DHT)、孕酮(PG)以及三碘甲状腺原氨酸(T3)的结合情况,并考察了雌激素受体拮抗剂4-羟基他莫昔芬(4-OHT)与酵母的相互作用.结果表明:ER+GRIP1和ER+SRC1酵母均能够专一性的和E2结合,并存在显著的剂量-效应关系,E2对ER+GRIP1和ER+SRC1酵母β-半乳糖苷酶活性诱导的EC50值分别为7.3×10-11mol·L-1和1.5×10-10mol·L-1,其中ER+GRIP1酵母细胞诱导产生的酶活性值明显高于ER+SRC1酵母细胞.4-OHT能够抑制E2诱导ER+GRIP1酵母细胞产生的酶活性,并存在显著的剂量-效应关系,IC50值为1.0×10-7mol·L-1.表明重组人雌激素受体基因酵母可以用于检测化合物和环境样品的类/抗雌激素活性.     

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.     

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.     

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.     

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.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).