新疆库尔勒市平原区地下水有机污染评价

本文采用有机污染现状评价法和环境影响度评价法对新疆库尔勒市平原区22组地下水水样进行评价,并对其影响因素进行了分析.地下水有机污染物检测结果显示,无有机污染物超标项,有6项有机污染物检出,分别为反-1,2-二氯乙烯、顺-1,2-二氯乙烯、三氯甲烷、1,2-二氯乙烷、四氯乙烯和甲苯,检出率最高的指标是甲苯(检出率为27.3%),其余5项检出率均为4.5%.地下水有机污染现状评价结果表明,研究区内甲苯未污染占72.7%、轻度污染占27.3%,其余5项未污染占95.5%、轻度污染占4.5%.地下水环境影响度评价结果表明,研究区地下水体中的有机污染物对人和环境没有明显的潜在危害.库尔勒市平原区地下水中有机污染物检出主要受工业污染源、生活污染源、农业污染源、土地利用类型和包气带岩性的影响.     

定靖油气田区地下水有机污染特征初步分析

以地下水水质检测数据为基础,从污染源分布及水文地质条件入手,对定靖油气田区地下水有机污染分布特征及其成因进行了研究,本文检测了卤代烃15项、氯代苯5项、单环芳烃5项、有机氯农药11项和多环芳烃1项,结果发现该地区地下水有机污染具有检出种类少,检出率高,浓度低,超标率低的特点.地下水中检出的有机污染物共有10种,分别为甲苯、苯、邻二甲苯、苯乙烯、二氯甲烷、1,2-二氯乙烷、1,2-二氯丙烷、1,2-二氯苯、1,2,4-三氯苯和苯并(a)芘,检出的9项有机污染物含量均低于《地下水质量标准》(GB/T14848—2007)三类水限值.潜水的检出项比承压水的检出项多,检出率普遍比承压水的检出率高.不同地貌类型的有机污染物检出率为黄土区(28.87%)≈平原区(27.76%)沙漠滩地区(11.11%)河谷区(3.33%).最后,从工业污染源、有机物理化性质和水文地质条件对有机污染分布特征的成因进行了阐述.     

新疆南部典型地区地下水中氟的分布特征及其富集因素分析

以新疆南部典型平原区地下水中的氟为研究对象,依据地下水污染调查数据,分析研究区地下水中氟的分布特征及富集因素.结果表明,水平上,焉耆盆地平原区地下水中氟的含量总体上呈南高北低,若羌-且末地区和叶尔羌河流域平原区地下水中的氟含量呈北高南低;垂向上,焉耆盆地平原区深层承压水的氟含量高于浅层承压水和潜水中的氟含量,若羌-且末地区和叶尔羌河流域平原区浅层承压水的氟含量高于深层承压水和潜水中的氟含量.地下水中的氟主要来源于地层中的含氟矿物;氟的富集主要受气候、地形、水文地质条件以及水化学环境的影响.     

新疆焉耆盆地平原区地下水演化的主要水文地球化学过程分析

地下水资源是焉耆盆地生活、生产及生态用水的主要供水水源.深入研究焉耆盆地地下水演化特征及水文地球化学过程对合理开发地下水资源及保护地下水环境具有重要意义.利用Gibbs图阐明了焉耆盆地平原区地下水所经历的水文地球化学作用(大气降水、蒸发浓缩和岩石风化作用等),平原区采样点主要分布在Gisbbs图的右上角及中部左侧,表明平原区地下水受风化、蒸发浓缩作用影响,且受大气降水作用影响较小;方解石、白云石等碳酸盐矿物,以及岩盐、石膏等蒸发岩的风化溶解是平原区地下水主要离子来源,应用PHREEQC地球化学模拟软件计算了平原区各矿物饱和指数,大部分采样点方解石与白云石未达到饱和状态;随着平原区地下水中的TDS和Cl-浓度的逐渐升高,Mg~(2+)在地下水中的富集受到了白云石沉淀过程的限制,而Ca~(2+)的含量随TDS的增大而持续增加,并结合平原区2011年与2014年地下水水化学Piper三线图,平原区地下水大部分呈Ca·Na型或者Ca·Mg型;地下水ORP值均为正值,表明平原区地下水处于氧化状态;根据离子比例法,γNa+/γ(Na++Ca~(2+)+Mg~(2+))比值深层承压水潜水浅层承压水,表明平原区地下水阳离子交换作用由强到弱依次为深层承压水、潜水、浅层承压水.     

华北平原地下水有机污染特征初步分析

各种污染造成地下水中有害物质逐年增加,地下水水质逐渐下降,严重危及了饮用水安全。针对此情况,按照相关的要求,采集了245组水样。样品由有资质的测试单位测定。依据对地下水质调查的初步分析,华北平原地下水中已有机物检出。对所有水样测试结果的统计显示：检出的有机污染物共有32种。检出率大于4.5%的有氯仿、甲苯、四氯乙烯、苯并[a]芘、氯苯、苯和1,2-二氯苯,其中个别水样中的四氯化碳、苯并[a]芘和挥发性酚类三项超过了饮用水标准（据地下水质量标准报批稿,中国地质调查局,2007）,超标率分别为1.22%、2.45%和1.90%。个别在深层地下水样品中也检出了微量有机污染物,这可能与取样井的混合开采、止水不佳有关。从区域上来看,在人类活动相对强烈的城镇地区地下水中,有机物检出率相对较高,特别是在渗透性好的山前地带,污染物较易进入到地下水中。通过分析发现,地下水有机物的高检出率与地下水硬度的升高有一定相关性。由于地下水有机污染在时间和空间上差异一般较大,建议对已发现的异常点进行重复取样测试,积累水质数据,以利于将来的综合分析。     

新疆南部典型地区地下水重金属空间分布特征

为研究新疆南部地区地下水重金属空间分布特征,在新疆南部选取典型区(叶尔羌河流域、焉耆盆地和若羌-且末地区),并对地下水重金属Fe、Cu、Mn、Zn、Hg、Cr(Ⅵ)、Pb、Cd、Al和As等10项指标进行了测试分析.结果表明,除Hg和Al外,其余指标均有检出;依据《生活饮用水卫生标准(GB5749—2006)》中的标准值,叶尔羌河流域Fe、Mn和As的超标率分别为48.0%、53.3%和20.0%,焉耆盆地Fe和Mn的超标率分别为11.9%和4.8%,若羌-且末地区Fe和Mn的超标率分别为33.3%和11.1%.研究区地下水重金属空间分布特征显著,水平分布上表现为叶尔羌河流域地下水重金属污染最为严重;垂向分布特征为地下水中超标的Fe、Mn和As主要分布于承压水区,且表现为浅层承压水中的超标率高于深层承压水的趋势.     

新疆喀什地区东部地下水“三氮”空间分布特征及影响因素

本文对新疆喀什地区东部地下水"三氮"空间分布特征及影响因素进行了研究.结果表明,该地区地下水"三氮"含量总体较低;NO_3-N含量范围为ND(未检出)—8.02 mg·L~(-1)、样点均值1.17 mg·L~(-1);NO_2-N含量范围为ND(未检出)—0.15 mg·L~(-1)、样点均值0.006 mg·L~(-1);NH_4-N含量范围为ND(未检出)—至0.28 mg·L~(-1)、样点均值0.04 mg·L~(-1);仅个别监测井NO_2-N和NH_4-N含量超标.水平分布特征表现为:NO_3-N含量总体呈南高北低,NO_2-N和NH_4-N含量总体呈南低北高.垂向分布特征表现为:潜水中NO_3-N含量(均值3.14 mg·L~(-1))高于浅层承压水(均值0.50 mg·L~(-1))和深层承压水(均值1.28 mg·L~(-1)),浅层承压水中NO_2-N(均值0.008 mg·L~(-1))和NH_4-N含量(均值0.05 mg·L~(-1))高于深层承压水(NO_2-N均值0.002 mg·L~(-1);NH_4-N均值0.02 mg·L~(-1))和潜水(NO_2-N均值0.001 mg·L~(-1);NH_4-N未检出);NO_2-N和NH_4-N超标点全部集中在浅层承压水中.该地区地下水"三氮"迁移和转化主要受氧化还原条件、地表水水质、包气带岩性、地下水径流条件、潜水埋深、土地利用类型和生活污染等因素的影响.     

新疆喀什地区地下水氟的空间分布规律及其富集因素分析

高氟地下水严重影响当地居民的身体健康.基于新疆喀什地区571个地下水样的氟离子实测含量,运用Mapgis软件绘制研究区地下水氟含量分布图,结果表明,研究区地下水氟含量呈西部、北部高于东部、南部,中部最低的特点;山麓斜坡冲洪积砾质平原区氟含量表现为浅层潜水高于深层潜水,中下游河流冲积平原区地下水氟含量表现为潜水浅层承压水深层承压水.采用绘制Gibbs图、Piper三线图、离子比例图等方法对研究区水化学环境特征及地下水氟的富集因素进行研究,结果表明,研究区地下水氟源于山前含氟基岩;受地下水径流条件影响,研究区地下水氟含量平均值表现为中下游河流冲积平原区山麓斜坡冲洪积砾质平原区;蒸发浓缩作用使F~-浓度进一步增大;研究区高氟地下水水化学类型主要为HCO_3-Na和Cl·SO_4-Na型,地下水弱碱性环境有助于F~-的富集.     

新疆阿克苏地区平原区高砷地下水分布特征及富集因素分析

地下水砷污染是全球化环境问题.本文基于阿克苏地区平原区2017年75个地下水砷实测含量进行分析.结果表明,研究区地下水砷含量变化范围为ND—98.70μg·L^-1,平均值为9.42μg·L^-1,超标率达26.7%.水平方向上,高砷地下水主要集中在研究区的中部偏南一带;垂直方向上,山麓斜坡冲洪积砾质平原潜水区地下水砷含量平均值表现为深层潜水>浅层潜水,中下游河流冲积平原区承压水区地下水砷含量平均值表现为深层承压水>浅层承压水>潜水.采用绘制Piper三线图、Gibbs图、离子比例图等方法对研究区地下水砷的富集因素进行研究.结果表明,研究区地下水砷主要为自然来源;封闭的地质构造和造山带与河流等沉积环境相结合的水文地质条件有利于研究区地下水砷的富集;研究区高砷地下水水化学类型主要为HCO3·SO4-Na,还原性-弱碱性环境利于地下水砷富集;研究区地下水砷受强烈的蒸发浓缩作用进一步浓缩,同时地下水阴离子浓度增大加剧了地下水中阴离子与砷酸根、亚砷酸根之间的竞争吸附,利于地下水砷的富集.     

廊坊市区地下水质量现状评价与分析

为阐明人类活动影响下廊坊市区地下水环境状况,2015年在研究区进行现场调查采集并分析了深浅层(包含3组地表水)水样50组,测试指标包括有机指标(30项)和无机指标(31项).利用基于分类指标的单指标综合评价法进行本区地下水质量评价.结果表明,研究区地下水质量综合评价结果较差,深层地下水相比浅层地下水水质较好;从分类指标来看,对区域地下水质量影响最大的为无机毒理指标,其次为一般化学指标,毒性(类)金属指标及有机指标对地下水质量影响很小,各项指标主要影响浅层地下水;单项组分分析表明,深、浅层地下水水质贡献指标相差较大,其中影响浅层地下水水质的主要指标有总硬度、"三氮"、砷、氟化物、铁锰等,深层地下水影响指标主要为氟化物(50.0%),其次为砷(13.6%);有机组分少量指标检出但无超标.分析认为原生水文地质环境和人类活动是影响该区地下水质量的主要因素,是导致地下水中污染组分异常的根源.     

On the behaviour of the residence time at the bottom of the mixed layer

To understand why the findings of Deleersnijder et al. [(2006), Environ Fluid Mech 6: 25–42]—the residence time in the mixed layer in not necessarily zero at the pycnocline—are consistent with those of Delhez and Deleersnijder [(2006), Ocean Dyn 56:139–150]—the residence time in a control domain vanishes at the open boundaries of this control domain—, it is necessary to consider a control domain that includes part of the pycnocline, in which the eddy diffusivity is assumed to be zero. Then, depending on the behaviour of the eddy diffusivity near the bottom of the mixed layer, the residence time may be seen to exhibit a discontinuity at the interface between the mixed layer and the pycnocline. If such a discontinuity exists, the residence time is non-zero in the former and zero in the latter. This is illustrated by analytical solutions obtained under the assumption that the eddy diffusivity is constant in the mixed layer.     

Observations on the function of the glands of the foot of the pediveliger of Ostrea edulis during settlement

The use during settlement of secretions of the 9 different types of gland in the foot of the pediveliger of Ostrea edulis L. was examined experimentally. During settlement, there is a progressive decrease in the crawling speed of the larva and a strengthening of its bond with the substratum. Both changes are related to (a) a change from ciliary to muscular pedal locomotion; (b) the increasing acidity and viscosity of the mucoid secretions used; (c) the secretion of a byssus thread by the glands of the byssus duet; (d) changes in the form and composition of this byssus. At the termination of settlement, the entire contents of 2 types of gland are discharged. Their secretions give rise to the cement which permanently fixes the larva to the substratum. The 9 types of gland are utilised sequentially in a manner closely related to the 6 phases recognised in settlement behaviour.     

刍议医院资产管理的现状及其对策

医院的固定资产和流动资产是医院赖以生存和发展的基础,是一项非经营性国有资产．目前公立医院固定资产、流动资产管理现状不容乐观,针对这种状况,首先分析问题形成的原因,然后提出管理的措施或建议,从而使资产管理工作规范化、制度化、科学化,使有限的卫生资源发挥出最大的社会效益和经济效益．参3．     

豪猪消化系统的解剖研究

为了了解豪猪的消化生理,为豪猪的人工饲养技术研究提供基础依据,以达到高效饲养豪猪的目的,笔者对豪猪的消化器官进行了系统解剖研究.结果表明:豪猪的胃为单室胃.盲肠很发达,这与其能够消化植物纤维有关.豪猪肝脏很发达,其重量为402 g,是其体重的4.59%,肝脏分叶多而明显.     

Mining of the forest and the time path of the price of timber

The paper analyzes the effect of transportation (site specific) costs and the effect of mining (depletion) of the forest on the time path of the price and of the net price of timber in two forestry models. The models differ in that one has zero costs and the other has positive costs. The analyses yield the standard mining theory results for certain cases. They also yield extentions of these results for cases with growth of the harvested trees and/or regeneration on the harvested land. The paper concludes, as one would expect, that the theory of the mine is useful in analyzing the time path of the price of timber.     

Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e. peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e. expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where economic growth, which requires more oil, would require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.     

Splitting the tail of the displacement kernel shows the unimportance of kurtosis

Animals disperse in space through different movement behaviors, resulting in different displacement distances. This is often described with a displacement kernel where the long-distance dispersers are within the tail of the kernel. A displacement with a large proportion of long-distance dispersers may have impact on different aspects of spatial ecology such as invasion speed, population persistence, and distribution. It is, however, unclear whether the kurtosis of the kernel plays a major role since a fatter tail also influences the variance of the kernel. We modeled displacement in landscapes with different amounts and configurations of habitats and handled kurtosis and variance separately to study how these affected population distribution and transition time. We conclude that kurtosis is not important for any of these aspects of spatial ecology. The variance of the kernel, on the other hand, was of great importance to both population distribution and transition time. We argue that separating variance and kurtosis can cast new light on the way in which long-distance dispersers are important in ecological processes. Consequences for empirical studies are discussed.     

Stimulation of fat-body production in the polyps of the coralPocillopora damicornis by the presence of mutualistic crabs of the genusTrapezia

A mutualism exists between the xanthid crabs of the genusTrapezia and their host corals,Pocillopora damicornis. It has previously been established that these obligate coral residents benefit the coral hosts by defending them against echinoderm predators and by increasing the survival of polyps located deep between the coral branches. In turn, the corals apparently benefit the crabs by producing lipid-filled structures on which the trapezid crabs feed; these fat bodies may contain some of the lipid which in previous studies of coral metabolism has been termed excess. It was determined by experiments conducted at the Hawaii Institute of Marine Biology that the presence of crabs in colonies ofP. damicornis stimulates the polyps to produce the lipid-filled fat bodies; removal of crabs causes corals to cease producing fat bodies. A structure very similar to the fat bodies ofP. damicornis has been reported inAcropora durvillei. Both of these coral genera ordinarily possess xanthid-crab mutualists. This association between branching corals and crustaceans may have evolved because corals of these genera provide shelter among their branches and because these shallow-water corals are evidently capable of releasing lipid which is excess to the corals' metabolic needs, but which can be utilized by the crabs.     

三峡库区消落带土壤中铅污染调查

报道了三峡库区长江干流及小江支流消落带土壤中重金属铅含量背景值的调查结果。结果表明，目前土壤未被重金属铅污染。