华南滨海小流域降雨入渗对地下水的补给分析

以华南滨海小流域——中山大学滨海水循环试验基地(试验基地)作为研究区,在对该流域地下水和雨水分别进行采样、实验分析的基础上,利用氯量平衡法(CMB)与地下水动态法计算了该流域的降雨入渗补给系数与给水度。研究发现,试验基地地下水主要受降雨补给,地下水埋深在雨季(4—9月)、旱季(10—3月)的变动范围大致为0～1.5 m与0～0.5 m。根据CMB计算结果,补给区、中间区雨季降雨入渗补给系数分别为旱季的1.3～1.6倍和1.3～2.0倍,且补给区大于中间区(M5井除外)。利用地下水动态法计算次降雨入渗补给系数,所得雨季、旱季的均值(7.6%和4.6%)与CMB计算结果(7.7%和5.3%)较为接近。给水度、雨强与入渗补给系数均存在一定的线性关系。将地下水埋深分别与降雨入渗补给量及潜水蒸发量进行多项式拟合对比,发现降雨入渗对地下水的最大入渗补给埋深约为2.3 m,当埋深为3.1 m时,地下水可获得最大净补给量。     

利用回归分析确定降水入渗补给量

目前常用降水量乘以降水入渗补给系数的方法计算降水入渗补给量,此法不能表现降水特征、蒸发等因素对降水入渗补给的影响．为解决不同时间尺度、不同降水特征和蒸发情况下的降水入渗补给量,在分析郑州地下水均衡试验场地中渗透仪实测入渗量、降水和蒸发资料的基础上,利用均匀设计法选取最优的与降水入渗补给量关系密切的前期降水量和蒸发量的期次,然后利用回归分析建立各岩性和埋深的年、月和日尺度上的降水入渗函数,可以比较准确的计算降水入渗补给量．表3,参9．     

土地利用变化对茂名市降水入渗补给量的影响

大气降水是地下水补给的主要来源,确定降水入渗补给量对地下水资源管理和规划有着重要意义。以茂名市为研究区,基于Wet Spass分布式水文模型及Geo SOS-FLUS模型,结合GIS技术,估算2010年的降水入渗补给量,分析未来土地利用变化及其对降水入渗补给的影响。结果表明,(1)降水大部分转化为蒸散发量,入渗补给量次之,年平均降水入渗补给量为684.63 mm;不同土地利用类型下,径流量、蒸散发量和降水入渗补给量存在显著差异性,由于城市规划的作用和区域土壤质地的差异,林地、居民用地的降水入渗补给能力较大,高达800 mm,荒地最小。(2)近20年来,居民大量开垦荒地,草地转变为耕地和林地,有利于降水入渗的土地利用类型面积减少,使得降水入渗补给量减少,土地利用变化影响着地下水的水量平衡。(3)到2050年,各类土地利用类型在区域上的分布更加集中,水域面积大量减少,耕地面积普遍大于其他类型土地,导致大部分面积的降水入渗补给量将呈现减少的趋势,全年、丰水期的降水入渗补给量变化较相似,与枯水期的变化相差较大;到2100年则偏向于林地和草地的增加,降水入渗补给量呈增加趋势。可见,在未来一段时期内,茂名市在追求经济高速发展的同时,应加强对生态环境的保护,加大绿化面积,使地下水得到一定量的补给。本研究结果可为茂名市未来土地规划提供一定依据,以进一步加强对地下水的管理和保护。     

降水入渗补给地下水过程分析

该文总结了降水入渗补给的模式,通过分析活塞式降水入渗、降水入渗补给的滞后和延迟、降水入渗优先补给等,研究了土壤不同岩性、不同埋深、不同降水时段与不同土壤含水量条件下的降水入渗补给过程．图5,表1,参8．     

再生水回灌地下水环境安全风险评价技术方法研究

再生水回灌是水资源管理的一条有效途径,也是污水再生利用的重要发展方向。然而,当再生水以农灌、土壤含水层处理（SAT）、河湖入渗和井灌等方式进行地下水回灌时,不可避免的会在回补地下水的过程中造成对地下水环境的污染风险。针对不同回灌方式建立适用于我国的再生水回灌地下水环境安全风险评价技术体系至关重要。借鉴国内外地下水污染风险评价方法,综合分析再生水回灌对地下水产生风险的关键环节,采用层析分析法,从回灌水特征污染物特性、回灌区地下水固有脆弱性以及回灌工程布设方式3个方面,针对地表灌溉、河湖入渗和井灌3种回灌方式,建立了包含污染物浓度水平、分配系数、溶解度、半衰期、半致死剂量、地下水埋深、降雨入渗补给量、地形坡度、土壤介质、包气带介质、含水层介质、含水层厚度、回灌强度、回灌周期、回灌水停留时间以及取水点与回灌点水平距离16个指标在内的风险评价指标体系。在此基础上,结合地下水使用功能,以20个典型再生水回灌场地调研结果和160种再生水回灌地下水污染风险因子物化特性为数据基础,对各指标进行了风险水平的划分,基于聚类分析法,采用各指标风险指数相乘的风险表征方法计算总风险指数,构建了再生水回灌地下水环境安全风险评价技术方法。该方法有效的避免了指标权重计算的主观性,并且能够直观的找出导致风险的主要因素。结果表明：利用建立的风险评价技术方法可将我国再生水回灌地下水环境安全风险划分为3级,风险值〈5为一级,风险值在5-15之间为二级,风险值〉15为三级。在某再生水回灌场地的应用表明,该回灌区地下水环境安全风险为二级,同时得出回灌水特征污染物特性指标是造成该回灌区地下水环境风险的主要因素。     

平原河网地区地下水脆弱性评价体系构建及应用

地下水污染形势严峻,脆弱性评价是区域地下水资源保护和污染防治的重要前提。平原河网地区地表水系复杂,城市化程度高,常规DRASTIC模型难以准确评价其地下水脆弱性。文章根据平原河网地区特点,建立了一套包括地下水埋深、净补给量、含水层介质、土壤带介质等7个本质脆弱性指标和地表水系、地下工程2个特殊脆弱性指标在内的方法体系,并以上海市金山区为例进行了地下水脆弱性评价。结果表明,地下水埋深、地下水净补给量和含水层厚度是影响评价区域本质脆弱性的主要指标,3者评价得分均在3~9之间,其中地下水埋深和净补给量得分为6的区域面积最大,分别为219.35 km~2和187.74 km~2,含水层厚度以得分为8的区域面积最大,达到286.01 km~2。金山区地表水系分布广泛,加上水质较差,其河流水质、河网密度、河流等级的脆弱性评价得分大多为6~10,相比地下工程,这3个指标对该区域的特殊脆弱性影响更大。金山区地下水综合脆弱性评价中,三级和四级面积较大,分别为274.49 km~2和157.82 km~2,两者面积之和占整个评价区的67.93%;三级区域广泛分布于整个评价区范围之内,五级脆弱性零星分布于南部和中部区域。评价结果与实际调研情况相符,能够真实地反映评价区浅层地下水脆弱性程度。该方法体系可为区域地下水环境管理及污染防治工作提供技术支撑和科学依据。     

流溪河流域地下水水化学时空特征及源辨析

流溪河承担了广州市白云区供水的重任,流域内的地下水作为应急水源具有重要的战略意义和生态维持作用.为合理开发利用流溪河流域地下水,了解地下水的形成及其离子的迁移和转化规律,分别于2015年8月和12月共采集90个地下水水样,通过分析地下水化学特征、稳定同位素D和18O分布规律,并利用Gibbs分布图和相关性分析揭示旱季和雨季的地下水化学时空分布特征、地下水及离子来源.结果表明,研究区地下水主要受降水补给.空间上,上游区受人类活动影响比中下游区小,从上游到下游区,水化学类型总体从Ca-HCO_3型和Ca-Na-HCO_3型向Ca-Na-HCO_3-Cl型、Ca-Na-Cl-HCO_3型和Na-Ca-Cl-HCO_3型转变,地层的岩性对于地下水类型影响较大;时间上,水化学特征季节性差异不显著.流域内主离子的来源主要为岩石风化,Ca~(2+)、Mg~(2+)、Na~+与HCO_3~-的来源以碳酸盐岩和硅酸盐岩风化为主,其中,碳酸盐岩的风化占主导地位;NO_3~-和Cl~-主要来自人类生活污染的输入,NH_4~+与TP主要来源于面源污染.     

广花盆地地下水三氮时空分布特征及影响因素分析

广花盆地是广州市唯一的地下水应急水源区。三氮(氨氮、亚硝酸盐氮和硝酸盐氮)是研究区地下水的主要污染物,通过分析其时空变化特征,探讨主要影响因素,可为广州市制定地下水保护与利用规划提供理论基础和科学依据。为准确掌握研究区地下水中三氮的分布,利用广花盆地80个地下水监测井2012—2016年的监测数据,分雨季和旱季分析了研究区松散岩类孔隙水、基岩裂隙水和岩溶水中三氮的时空分布特征,并利用相关系数定量分析了降雨量与氮含量之间的相关性,采用灰色关联法计算了耕地面积、化肥施用量、降雨量与氮含量之间的关联度,以及从垂向和水平两个方向探讨了氮含量变化的原因。结果表明,2012—2016年广花盆地0~100 m深度地下水的氮污染较严重,氨氮、亚硝酸盐氮和硝酸盐氮的超标率分别为47%、29%和5%。由于松散岩类孔隙水、基岩裂隙水和岩溶水均属浅层地下水,相互联系紧密,其含氮污染物的分布极为相似,氮含量按从大到小排列均为硝酸盐氮、氨氮和亚硝酸盐氮,超标率按从大到小排列均为氨氮、亚硝酸盐氮和硝酸盐氮。受氧化还原环境的影响,随地下水埋藏深度的增加,广花盆地地下水中的氮含量逐渐减少,其中氨氮和亚硝酸盐的含量逐渐增大,硝酸盐氮的含量逐渐减小。受土地利用类型的影响,研究区地下水中三氮的空间分布差异较大。其中城乡居民区地下水的污染最严重,其污染主要来源于废污水的排放。近5年耕地地下水中氮的含量随时间呈减少趋势,主要是受耕地面积减少所致。总体而言,近5年研究区地下水中氮的含量随降雨量增大而减小,并随雨季和旱季的交替而增减,雨季地下水中氮的含量较旱季小。     

崇明东滩围垦湿地芦苇生态特征与水盐因子的关系

芦苇是崇明东滩围垦湿地生态系统的重要优势物种和建群种,了解芦苇与滨海围垦区湿地土壤水盐因子的关系对于围垦区湿地水盐调控管理和湿地植被恢复具有重要意义.以崇明东滩围垦湿地芦苇(Phragmites australis)为研究对象,通过野外调查与统计分析,探讨滨海湿地芦苇生态特征与地下水埋深(Ground water depth,WD)和土壤电导率(Siol electrical conductivity,EC)的关系.结果表明:研究区地下水埋深与表层土壤电导率呈显著负相关,相关系数为-0.883;沿着高程从高到低,地下水埋深逐渐升高,土壤电导率逐渐降低,在不同水盐梯度下芦苇种群表现出相应的生态特征,芦苇密度、株高、单株叶面积、单株生物量、叶面积指数和单位面积地上生物量均沿着高程的降低而增加.Pearson相关性分析表明,地下水埋深与芦苇生态特征呈显著正相关,而土壤电导率与芦苇生态特征呈显著负相关,并且土壤电导率与芦苇生态特征的相关性大于地下水埋深.回归分析发现芦苇在土壤水埋深较低区域(-5 cm以下)生长受到限制,表现为低密度、低生物量;在地表有少量积水的土壤环境中(0 cm以上)芦苇生长状况较好,表现为高密度、高生物量.随着土壤电导率的增加,芦苇以低密度、低生物量的生态特征来适应胁迫伤害.当土壤电导率5 m S/cm,随着土壤电导率增加,芦苇生长指标快速下降,而当土壤电导率5 m S/cm,芦苇生长指标下降幅度较小.本研究表明,适当提高芦苇湿地年平均土壤水埋深有利于降低土壤表层土壤电导率,并且提高土壤水埋深均有利于芦苇单株生长和种群生长.     

新疆喀什噶尔河岸植被对地下水埋深的退化响应

地下水是干旱区重要的环境因子,影响着植被的生长分布.基于2018年新疆喀什噶尔河岸的监测井与植物样地监测数据,分析了研究区不同地下水埋深梯度的植物生长与群落分布情况,讨论地下水埋深对植被退化的影响,结果表明:1)研究区主要以乔木和灌木为主,其中胡杨出现频次最高,是研究区优势植被,其盖度和高度较小,长势受到地下水埋深制约...     

深圳铁岗水库水体中抗生素污染特征分析及生态风险评价

近年来水体中不断被检出的抗生素逐渐成为研究者关注的焦点。许多国家的河流、湖泊、地下水中均检出了抗生素残留。目前国内外关于抗生素污染特征的研究主要集中在河流、河口湾和污水处理厂等水环境中,对于抗生素在饮用水源地水体中的污染状况研究极少。利用高效液相色谱-串联质谱技术（HPLC-MS/MS）检测分析了5类典型抗生素在深圳铁岗饮用水源地型水库中的污染特征。结果表明,9种目标抗生素中,有8种在铁岗水库水体中被检出,浓度范围为1.1～203 ng·L^-1,其中,林肯霉素检出浓度最高,红霉素次之,阿莫西林未检出;入库支流抗生素污染程度普遍高于铁岗水库,其中大官陂河中抗生素质量浓度最高（277.0 ng·L^-1）,九围河次之（196.4 ng·L^-1）;枯水期抗生素浓度高于丰水期。采用风险商值法初步评价的结果表明,枯水期时料坑水中红霉素、大官陂河中磺胺甲噁唑和林肯霉素,以及丰水期时九围河中林肯霉素的生态风险商（RQ）均大于1,对生态环境具有高风险;风险简单叠加模型计算结果显示,枯水期时料坑水、塘头河、大官陂河以及丰水期时九围河中抗生素的联合毒性风险商（RQsum）均大于1,对生态环境可能会产生较高的风险。     

Distribution,enrichment mechanism and risk assessment for fluoride in groundwater: a case study of Mihe-Weihe River Basin,China

● High fluorine is mainly HCO₃·Cl-Na and HCO₃-Na type. ● F⁻ decreases with the increase of depth to water table. ● High fluoride is mainly affected by fluorine-containing minerals and weak alkaline. ● Fluorine pollution is mainly in the north near Laizhou Bay (wet season > dry season). ● Groundwater samples have a high F⁻ health risk (children > adults). Due to the unclear distribution characteristics and causes of fluoride in groundwater of Mihe-Weihe River Basin (China), there is a higher risk for the future development and utilization of groundwater. Therefore, based on the systematic sampling and analysis, the distribution features and enrichment mechanism for fluoride in groundwater were studied by the graphic method, hydrogeochemical modeling, the proportionality factor between conventional ions and factor analysis. The results show that the fluorine content in groundwater is generally on the high side, with a large area of medium-fluorine water (0.5–1.0 mg/L), and high-fluorine water is chiefly in the interfluvial lowlands and alluvial-marine plain, which mainly contains HCO₃·Cl-Na- and HCO₃-Na-type water. The vertical zonation characteristics of the fluorine content decrease with increasing depth to the water table. The high flouride groundwater during the wet season is chiefly controlled by the weathering and dissolution of fluorine-containing minerals, as well as the influence of rock weathering, evaporation and concentration. The weak alkaline environment that is rich in sodium and poor in calcium during the dry season is the main reason for the enrichment of fluorine. Finally, an integrated assessment model is established using rough set theory and an improved matter element extension model, and the level of groundwater pollution caused by fluoride in the Mihe-Weihe River Basin during the wet and dry seasons in the Shandong Peninsula is defined to show the necessity for local management measures to reduce the potential risks caused by groundwater quality.     

珠江三角洲小流域地下水化学特征及演化规律

珠江三角洲地下水环境日益恶化,已成为制约经济社会发展的重要因素。以珠海市具有典型特征的闭合小流域作为研究对象,分旱、雨两季采集地下水分析主要离子及D、18O同位素,全面系统地研究了地下水水化学的时空变异特征与演变规律。结果表明:研究区内地下水主要受大气降水及附近地表水体渗透补给,以蒸发及地下水径流排泄,季节变化对区域内水化学空间变异性影响较小。沿地下水流方向(补给区-径流区-排泄区),地下水化学类型主要从Ca-Na(Mg)-HCO3型向Na-Cl和Na-K-HCO3-CO3型演化,风化-溶滤、离子交换、海陆交互作用是控制当地地下水质演变的主要水文化学过程。     

Environmental influences on larval duration,growth and magnitude of settlement of a coral reef fish

The influence of environmental variables on the planktonic growth, pelagic larval duration and settlement magnitude was examined for the coral reef surgeonfish Acanthurus chirurgus. Newly settled fish were collected daily from patch reefs in the San Blas Archipelago, Caribbean Panama for 3.5 years. Environmental influences on growth were examined at three different life history stages: from 0 to 6 days, 7 to 25 days and from 26 to 50 days after hatching. Larval growth was correlated, using multiple regression techniques, with a combination of factors including solar radiation, rainfall, and along-shore winds. Depending on the life history stage, these accounted for 13–38% of the variation in growth rates when all the months were included in the analyses. Correlations between environmental variables and growth also varied among seasons and were stronger in the dry than in the wet season. During the dry season solar radiation, rainfall and along-shore winds described 57%, 86% and 74% of the variability in growth between 0 and 6 days, 7 and 25 days and 26 and 50 days, respectively. During the wet season rainfall, along-shore winds and temperature only described 38% of the variability in early growth and 27% of growth just before settlement. No significant model was found to describe growth 7–25 days after hatching during the wet season. Rainfall, solar radiation and along-shore winds were negatively correlated with growth up to 25 days after hatching but positively correlated as larvae approached settlement at a mean age of 52 days. Over 65% of the variability in pelagic larval duration was accounted for by a regression model that included solar radiation and along-shore winds. When data sets from wet and dry seasons were analysed separately, along-shore winds accounted for 67% of the change in larval duration in the dry season, and solar radiation accounted for 23% of the variation in larval duration in the wet season. Only 22% of the variability in settlement intensity could be described by solar radiation and temperature, when all months of the year were included in the analysis. Solar radiation and rainfall were included in a regression model that accounted for 40% of the variation in numbers of fish settling during the dry season. This study suggests that the levels of solar radiation, along-shore winds and rainfall during the early larval life can have important effects on the growth, larval duration and consequently, the settlement magnitude of marine fishes. Results also highlight the need to account for seasonality and ontogeny in studies of environmental influences.Communicated by G.F. Humphrey, Sydney     

长江口湿沉降汞的时间分布及潜在生态危害

于2008年2月-2009年1月逐月采集长江口右岸陈行采样点的大气湿沉降样品,测试样品的总汞、溶解态汞浓度。分析结果显示,不同月份湿沉降中各形态汞的浓度变化较大,其中总汞浓度变化范围在0.09-0.45μg/L,体积加权平均值为0.22μg/L,总汞沉降通量高达199.79μg/（m2.a）,远高于其它地区,该区域的大气已经受到一定程度的汞污染。总汞、颗粒态汞月沉降量与降水量呈明显的正相关关系（除6月份）,总汞浓度与降水量在汛期（6-9月份）具有良好的负相关性,大气湿沉降汞的形态受到人为活动产生的颗粒物的影响,颗粒态汞占总汞比例变化范围在14%-89%之间,平均为62%。以地表水Ⅲ类标准0.1μg/L为评价标准,长江口湿沉降汞的潜在生态危害系数高,全年湿沉降汞平均值属于强生态危害范围。     

粤北2座饮用水源地水库的富营养化与浮游植物群落动态

粤北地区的水库以山地型水库为主,其中有不少担负着饮用水源的功能。为了解粤北地区水源地水库的富营养化状态与浮游植物种群的动态变化,于2011年的枯水期（2―3月）和丰水期（6―7月）对花山和白水礤2座中型水库进行了采样调查,对水库的营养盐和浮游植物种群进行了分析。结果表明：2座水库均为贫营养型;浮游植物在枯水期和丰水期的种类变化不大,共鉴定出的浮游植物6门37种（属）,以硅藻为主要优势种群,优势种为小环藻（Cyclotella sp.）和颗粒直链藻（Melosira granulata）。同时,枯水期和丰水期2座水库浮游植物的丰度和生物量都比较低,其值分别为0.65×106～1.95×106cells.L-1、0.11 mg.L-1和0.73×106～8.9×106cells.L-1、0.05～0.50 mg.L-1。在浮游植物种群动态中,2座水库浮游植物丰度和生物量的季节变化主要表现为硅藻丰度和生物量的变化,低浓度的氮、磷营养盐限制是影响这2座贫营养水库浮游植物动态变化主要因素。     

Annelids of a west African estuarine system

Annelids collected from eight stations in the western part of Lagos Lagoon between May, 1996 and February, 1998 were reported. Rainfall, salinity and sediment type influenced distribution of annelids, which were either dry season species, wet season species or euryhaline species. A total of fifty-five species were collected, thirty-one not recorded in earlier studies. Pollution indicators, Polydora sp., Capitella capitata, Nereis sp. and Tubifex sp. were collected in both dry and wet seasons.     

Vegetation competition model for water and light limitation. II: Spatial dynamics of groundwater and vegetation

In temperate climates groundwater can have a profound effect on vegetation, because it strongly influences the spatio-temporal distribution of soil moisture in the rootzone and therefore the occurrence of water and oxygen stress of vegetation. This article focuses on vegetation and groundwater dynamics along a hill slope by developing and evaluating a fully coupled hydrological-vegetation model for a temperate forest ecosystem. The vegetation model is described in part 1 of this series of two papers. To simulate the hydrology an extended version of the saturated-unsaturated hydrological model STARWARS has been used. The coupled model is used to investigate both the short and long-term dynamics for a system of two species. Both compete for light and water where one is adapted to wet conditions and the other to dry conditions. The daily dynamics show that the influence of groundwater is particularly strong in spring when waterlogging occurs due to decreased evapotranspiration in winter. Long simulation runs of 1000 years were performed to study the equilibrium state for the two species. Comparison of simulation results with observations of groundwater depth and vegetation types along a dry-wet gradient in a natural forest shows that a reductionist approach is able to capture these patterns well. Sensitivity analysis shows that the border between wet- and dry-adapted species moves upslope with increased rainfall, decreased slope angle and decreased aquifer thickness. These results are similar to previous findings which were based on global maximization of ecosystem evaporation or minimizing ecosystem stress. Comparison of runs with a fixed and a dynamic groundwater table shows that a dynamic groundwater table facilitates a wider transition zone between vegetation types along the hill slope. In this transition the biomass of vegetation is higher in the case of a dynamic groundwater than in case of a static groundwater table. This underlines the importance of incorporating spatial groundwater dynamics in models of groundwater influenced ecosystems.