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1.
北京密云水库小流域地下水硝酸盐污染来源示踪   总被引:4,自引:0,他引:4  
为确定北京密云水库小流域地下水中氮污染特征及来源,分别在雨季和旱季采集34个地下水样进行分析.结果表明,该流域地下水中NO-3-N污染严重,雨季和旱季NO-3-N的平均含量分别为15.86 mg·L-1和14.67 mg·L-1,均超过世界卫生组织饮用水标准(10 mg·L-1),污染主要分布于人口密集、农业活动频繁的中部地区.研究区域NH+4-N和NO-2-N的含量较低,其中,NO-2-N分布极不均匀.雨季和旱季δ15N的变化范围分别为5.00‰—20.16‰和-5.90‰—12.28‰,表明地下水硝酸盐的主要来源为人畜粪便和污水的排放,也可能为土壤有机氮和农业施肥的混合,表明旱季发生反硝化作用造成同位素的分馏.雨季,硝态氮与村镇面积呈正相关;氨氮与村镇及地表水面积呈显著正相关关系.旱季,硝态氮与村镇面积呈正相关,氨氮与草地面积呈正相关,亚硝态氮与地表水面积呈显著的正相关关系.  相似文献   

2.
为明确蔬菜常用农药在地下水中的环境风险,运用China-Pearl和SCI-GROW模型开展地下水环境暴露评估,并根据我国成人和儿童暴露参数推导25种农药预测无效应浓度(PNEC)。研究发现,25种农药PECgw为0~18.340μg·L-1,成年人PNECgw为0.003~19.654 mg·L-1,儿童PNECgw为0.001~23.253 mg·L-1。成年人和儿童的RQgw值均小于1,表明25种农药按照登记用量使用,我国成人和各年龄阶段儿童直接饮用施用农药区域地下水的环境风险可接受。  相似文献   

3.
博斯腾湖流域地下水重金属污染的人体健康风险评估   总被引:2,自引:0,他引:2  
在新疆博斯腾湖流域绿洲灌区采集67个浅层地下水样品,测定其中Cu、Mn、Cd、Cr、Ni和Zn等6种重金属元素的含量,采用Nemerow综合污染指数对地下水中重金属污染程度进行评价,借助US EPA健康风险评价模型对地下水中重金属污染的潜在健康风险进行评价。结果表明:(1)地下水中各元素平均含量大小顺序依次为:MnZnCuNi CrCd,各元素平均含量均未超出国家标准的限值;(2)研究区地下水中各重金属元素单项污染指数平均值从大到小依次为:Cd(2.04)、Mn(0.69)、Ni(0.45)、Cr(0.24)、Zn(0.07)、Cu(0.03)。综合污染指数的变化范围在0.23~2.22之间,平均值为0.73,呈现轻微污染;(3)健康风险评价结果表明,地下水中6种重金属对成人的潜在非致癌健康风险HI为7.83E-011,表明暴露的个体不太可能有明显的不良健康影响;对儿童的潜在非致癌健康风险HI为1.05E+011,表明研究区地下水重金属可能对当地儿童的健康产生不利影响,有进一步研究的必要性。  相似文献   

4.
成都平原表层水稻土重金属污染健康风险分析   总被引:8,自引:0,他引:8  
杨刚  李燕  巫林  谢丽苹  伍钧 《环境化学》2014,(2):269-275
采样分析了成都平原表层水稻土(0—20 cm)中As、Cd、Cr、Hg、Pb、Cu、Zn含量,参照国家土壤环境质量标准和土壤背景值,并利用健康风险评价模型对土壤重金属环境质量状况和人体健康风险进行了评价.结果表明,成都平原水稻土表层7种重金属平均含量分别为As:9.69 mg·kg-1、Cd:0.12 mg·kg-1、Cr:79.5 mg·kg-1、Hg:0.04 mg·kg-1、Pb:47.5 mg·kg-1、Cu:29.3 mg·kg-1、Zn:81.7 mg·kg-1.与成都地区土壤背景值相比,As、Cr、Pb、Cu、Zn在表层水稻土中有明显积累,部分样区土壤重金属超过《土壤环境质量标准》(GB15618—1995)标准值的二级标准,存在外源污染输入,但污染程度较轻.人体健康风险分析结果表明,经土壤-口接触行为摄入是该区域人体重金属暴露风险的主要途径,重金属致癌风险AsCd,非致癌总风险CrCuHgPbZn,无论儿童还是成人,重金属致癌风险值和非致癌风险值均低于风险阈值,风险值均在可接受水平内,但儿童健康风险值高于成人,应加强监管.  相似文献   

5.
水肥耦合效应对保护地土壤硝态氮运移的影响   总被引:2,自引:0,他引:2  
采用二次回归正交旋转组合设计,研究了水肥耦合效应对保护地土壤硝态氮运移的影响。结果表明,0—20cm土层硝态氮含量主要受灌水和施氮的影响,且灌水影响程度大于施氮,灌水与0—20cm土层硝态氮含量呈负相关,而与施氮呈正相关。20—40cm土层和40—60cm土层硝态氮也主要受灌水和施氮的影响,但施氮影响程度大于灌水。灌水和施氮对0—20cm土层硝态氮含量影响有相互拮抗作用。施磷对3个层次土壤硝态氮含量影响都很小。  相似文献   

6.
土壤氮素迁移规律是农业面源污染研究的重要内容,探讨不同土地利用方式下氮素垂直分布及其影响因素对氮迁移规律研究具有重要意义。在亚热带典型红壤丘陵区利用动力土柱机采集了38个稻田、林地和茶园的1 m深原状土柱,分0~20、20~30、40~50和70~80 cm 4层并间隔5 cm取样分别测定铵态氮、硝态氮和全氮以及其他土壤属性,研究氮素垂直分布对土地利用方式的响应及其影响因素。结果显示:(1)稻田上述4层土壤全氮含量显著高于林地和茶园(P0. 05),土壤铵态氮含量在各土地利用方式间差异不显著。就表层(0~20 cm)硝态氮含量而言,稻田土壤显著高于林地和茶园;茶园下层(20 cm)土壤硝态氮含量显著高于稻田和林地。(2)土壤全氮含量与硝态氮含量关系密切(r=0. 64,P0. 01);有机碳含量、土壤剖面深度和容重是影响氮素垂直分布的重要因子,土壤氮含量与有机碳含量之间呈显著正相关,与容重、土壤剖面深度呈显著负相关(P0. 05),表明土壤性质对氮素的分布有重要影响。该研究有助于评价红壤丘陵区农业氮肥施用对水体污染的影响风险。  相似文献   

7.
选择典型废弃日用品塑料,对特征处置场景下其PBDEs的浸出特征及健康风险进行了评价.结果表明,日用品塑料在硫酸/硝酸、醋酸和腐殖酸溶液中达到溶出平衡时,∑21PBDEs释放量分别为20.00、63.65、125.60μg·kg-1,均以BDE209为主.进入生活垃圾填埋场的释放量高于堆存和简易填埋过程,在最不利条件下距填埋场下游500 m处地下水中PBDEs最大浓度为39.67μg·L-1,居民饮用地下水产生的非致癌风险指数为2.11×10-1,其中十溴代物(BDE209)的非致癌风险指数为1.85×10-1,均小于美国标准中非致癌的可接受风险水平(1.0),表明废旧日用品塑料可进入生活垃圾填埋场处置.  相似文献   

8.
石油污染滩涂生物体内TPH分布及健康风险评估   总被引:1,自引:0,他引:1  
通过研究溢油事故污染区域中典型生物体内TPH(Total Petroleum Hydrocarbons)分布特征,对其进行暴露人体健康风险评估,从而为污染区域的生态系统修复与恢复工作提供指导依据。在研究区域受溢油污染并采取应急处置10个月后,采集了位于4个污染滩涂集中填放区和1个不受污染的对照区内的生物体和沉积物样品,采用紫外分光光度法和荧光分光光度法测得 TPH 含量。结果表明,污染区域中无齿螳臂相手蟹 Chiromantes dehaani)肌肉组织中的 TPH 含量分布范围为2.94~39.63 mg·kg-1,内脏中的TPH含量分布范围为8.62~155.41 mg·kg-1,内脏组织中的TPH含量高于肌肉组织,两者呈显著的相关性(Pearson相关系数r=0.9456)。受潮汐水动力等环境因素的影响,整个研究区域生物体内TPH的累积呈现不连续非均质特征。生物体肌肉和内脏组织中的TPH含量与沉积物中TPH含量具有明显的线性关系(y=283.3 x+100,r2=0.9901;y=60.701 x+100,r2=9038),溢油事故造成的沉积物污染是影响生物体内TPH累积的一个重要因素。同时,采用US EPA人体暴露风险评价方法进行人体健康风险评估,结果显示,污染区域生物体内TPH经口摄入的暴露风险指数ERI均值均大于1,分别为1.13、1.05、2.58、2.73,暴露风险处于不可接受水平。根据人体健康风险的可接受水平计算得出可接受的无齿螳臂相手蟹体内TPH安全值为34.4 mg·kg-1,进一步计算得出污染区域沉积物中TPH的修复目标值为2513 mg·kg-1。  相似文献   

9.
为探明九龙江流域表层水体氮污染分布特征及其污染来源,于2020年7月(丰水期)和2021年1月(枯水期)开展九龙江全流域表层水体多点多断面原位观测,利用正定矩阵因子分析模型(positive matrix factorization, PMF)对不同水期全流域表层水体氮污染来源及贡献率进行解析,耦合相关性统计分析方法研究不同水期流域表层水体氮污染的关键驱动因子。结果表明,九龙江流域表层水体氮污染存在明显的水期分异特征,ρ(TN)为0.72~13.14 mg·L-1,丰水期ρ(TN)为1.39~10.95 mg·L-1,枯水期为0.72~13.14 mg·L-1。硝态氮(NO3--N)、氨氮(NH4+-N)、亚硝态氮(NO2--N)和溶解性有机氮(DON)浓度均表现为丰水期大于枯水期,但颗粒态氮(PN)浓度则表现为枯水期大于丰水期。丰水期氮污染以NO3-  相似文献   

10.
为了研究贵州遵义松林Ni-Mo多金属矿区土壤和农作物Mo污染情况,测定矿区不同类型土壤(旱地土、水稻土和森林土)和农作物样品Mo含量,采用地质累积指数法评价了土壤Mo污染状况,并采用危险商法评价农作物Mo健康风险.分析结果显示,矿区旱地土、水稻土和森林土Mo平均含量分别为64.66 mg·kg~(-1)、11.83 mg·kg~(-1)和40.24 mg·kg~(-1),相比于本研究的对照样品Mo含量(0.54 mg·kg~(-1))及贵州土壤Mo背景值(2.40 mg·kg~(-1)),3种类型土壤均具有高Mo含量特征.地质累积指数评价结果显示,3种类型土壤均出现不同程度的Mo污染.其中,旱地土Mo污染最为严重,污染级别在中度污染至极重污染之间;其次为森林土,处于中度污染至重度污染-极重污染之间;水稻土Mo污染相对较轻,污染级别在轻度污染至中度污染-重度污染之间.6种农作物样品Mo含量范围为0.36—59.97 mg·kg~(-1).危险商法评价结果表明,水稻和白菜的健康风险指数(HQ)大于1,长期食用可能对人体产生一定的健康风险;玉米、甘薯、辣椒和萝卜的健康风险指数小于1,对人体造成健康风险的可能性较小.若同时食用这6种农作物,Mo造成的总风险值高达3.62,存在较高的健康风险.季节性食用农作物(玉米、甘薯、白菜和萝卜)在食用季节(秋季)将具有更高的健康风险.本研究的结果表明,矿区Mo元素存在Ni-Mo多金属矿石及其围岩(黑色页岩)-土壤-农作物的迁移过程,并在土壤和农作物中富集,造成了一定程度的土壤Mo污染和农作物Mo健康风险.  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
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   

16.
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.  相似文献   

17.
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   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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   

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