铜绿微囊藻增值对水体内源磷污染的影响

<正>通过控制外源营养盐流入可以降低水体营养盐浓度,抑制蓝藻爆发。目前一些外源控制措施已经用于富营养化水体的修复,并取得一定成效。但是仅仅控制外源污染并不能抑制蓝藻爆发,底泥中营养物质的释放(内源污染)受到人们广泛关注。目前关于富营养化水体内源污染治理机制是抑制底泥中营养物质向上覆水迁移,如:底泥覆盖和底泥疏浚、生态修复等。但是这些措施成本高、时间长,难以大规模应用。本文基于磷是富营养化水体控制因子,研究铜绿微囊藻增值与底泥磷释放关系及其对底泥形态结构的改     

利用薄膜扩散梯度技术估算红枫湖沉积物磷释放通量

湖水因季节性分层而导致底层滞水带缺氧的亚深水型湖泊,其沉积物内源磷释放对水体磷循环和富营养化有着重要影响。选取典型的高原亚深水型湖泊——贵州红枫湖为研究对象,借助氧化锆薄膜扩散梯度技术获取了5个代表性湖区沉积物有效磷(labile P)的原位、二维、高分辨分布信息,在此基础上估算夏季红枫湖沉积物内源磷释放通量。结果表明,红枫湖后五沉积物有效磷浓度最高,羊昌河、大坝次之,南湖中与北湖中较低。红枫湖沉积物labile P浓度在亚毫米水平上有很大差异,空间分布不均一,时间上夏季磷释放量为6270~7999kg,占全湖水体总磷的22%~28%。沉积物磷释放是红枫湖水体磷的重要来源,在湖泊富营养化防治过程中应予以重视。     

深水湖泊增氧理论与技术研究进展

深水湖泊由于自身物理结构特性,易形成垂直热分层。温跃层阻碍了上层水体中氧气向下转移,使得深水层长期处于缺氧状态,加速了沉积物内源污染物的释放,并导致湖泊水质恶化。利用增氧技术提高深水湖泊水体氧含量是抑制内源污染物释放、改善湖泊水质的一项有效措施。系统论述了国内外深水湖泊增氧方法与原理,深入剖析了人工去分层增氧技术、气体提升增氧技术、Speece锥形增氧技术和气泡羽流扩散增氧技术等4种主要增氧技术的结构与优缺点,介绍了典型深水湖泊增氧技术应用实例研究进展,对比分析了主要深、浅水增氧系统的差异,提出了目前增氧技术存在的主要问题,并对未来研究方向进行了展望。     

上覆水溶解氧水平对苏州城市河道底泥吸附/释放磷影响的研究

为了解上覆水体中溶解氧水平对底泥释放磷的影响,采用室内静态模拟的方法,控制在无外源污染的情况下,模拟水体的三种溶解氧水平范围,好氧、厌氧和自然状况,研究不同的溶解氧水平对底泥释放或吸附营养盐的影响。研究结果表明,溶解氧小于0.5mg/L的厌氧状况能加速底泥中磷的释放,溶解氧大于5.0mg/L的好氧状况则抑制底泥中磷的释放。因此要提高水质,降低内源负荷(底泥中)磷的释放,应该控制水体中的各种耗氧物,提高水体的溶解氧水平。     

沉积物中磷的赋存形态及磷形态顺序提取分析方法

阐述了当前我国水体富营养化的现状,水体的富营养化与水体中磷、氮的浓度以及二者的浓度比值有着密切的关系。水体富营养化时氮和磷的浓度均很高,但没有一个固定的值,是在一个较宽泛的富营养范围内,氮和磷的浓度比值大多在10∶1～20∶1。湖泊沉积物作为湖泊水体中磷的重要蓄积库,是湖泊流域磷循环的重要归属,也是湖泊水体内源性磷的主要来源,沉积物中极少量的稳定磷转化为活性磷就会造成湖泊水体富营养化。文中介绍了沉积物中无机磷形态的分类,评述了欧盟标准局在研制湖泊沉积物磷形态标准物质时比对采用的4种提取方法(Willimas法、Hieltjes-Lijklema法、Ruttenberg法、Golterman法),总结了国内外学者所应用的沉积物中磷的各种形态提取方法和磷各形态的分析测定方法,国内学者应用的方法是在国外学者方法的基础上提出的,阐述了顺序提取方法及其地球化学意义。简要评述了湖泊沉积物中磷的生物释放、物理释放和化学释放三种释放机制,这三种释放机制相辅相成,在一特定的环境条件下某一过程可能占主导地位来控制沉积物磷的释放。最后提出应该加强对沉积物中磷的各种形态的专属提取剂及其提取有效性的分子表征和检测,更加细化对于沉积物中磷形态的分类和创新各种磷形态的分析方法,建立沉积物-水体磷的迁移、循环和转化模型,这对于从根本上解决富营养化问题具有重要意义。     

河道底泥重金属污染的原位修复方法综述

随着城市化的推进,湖泊、河流等水系受到了不同程度的污染。底泥是水中各类污染物的主要蓄积地,底泥中各种污染物,尤其是重金属含量超标,会对水体、水生生物及人类造成严重危害。底泥中的重金属主要蓄积在表层,故水体环境一旦发生变化,底泥中的重金属便容易重新释放,造成二次污染,由此凸显了原位修复技术的优势。重金属污染底泥的原位修复技术旨在不改变污染底泥空间位置的条件下对底泥进行修复,该技术具有对原有环境影响小、成本低、不额外占用空间等优势,在未来的污染底泥修复中呈现出较大的潜力。本文对当前国内主要水系底泥的重金属污染状况以及修复技术进行分析概述,同时重点介绍底泥重金属污染的原位修复技术,并对底泥重金属污染原位修复技术的应用与发展进行展望。     

滇池现代沉积物中磷的地球化学及其对环境影响

湖泊沉积物中,磷是产生富营养化的重要元素.湖泊中磷元素含量、地球化学行为以及它的复杂矿物学特征,使人们对磷的研究极为重视.滇池湖中总磷超标10.3倍,底泥沉积物中P2O5平均含量0.52%,最高可达1.92%.滇池地处磷矿区,是磷质来源最丰富的湖泊,统计表明,磷含量每年在不断增长.滇池沉积物中磷主要以吸附态、有机态、铁结合态、钙结合态、铝结合态等几种形式存在.这些形态磷在底泥中是不稳定的,它们在环境改变条件下,又将磷释放到水体中.微生物在磷的循环过程中起了重要作用,乳酸菌对不溶性磷酸盐的分解,使湖泊中可溶磷含量增高.聚磷菌对磷元素的富集以及聚磷菌死亡后发生有机磷的矿化作用,是湖泊中水合磷酸盐矿物沉积的重要途径.当湖泊中这种不稳定的水合磷酸盐矿物在条件具备的情况下,经沉积物覆盖成岩作用后,最终形成磷灰石。     

平水期洞庭湖不同形态磷赋存特征

通过现场调查和室内实验,对平水期洞庭湖24个断面上覆水-沉积物磷的污染程度、分布特征进行研究;同时,分析了各形态磷间的相关性,探讨了磷的赋存形态对水体富营养化的影响、沉积物释放量和释放风险。结果表明,水体内总磷分布规律为南洞庭西洞庭东洞庭大通湖,东洞庭湖以颗粒态磷为主,西洞庭湖、南洞庭湖、大通湖均以溶解态磷、无机磷为主。沉积物中总磷的分布规律为南洞庭西洞庭东洞庭大通湖。东洞庭湖、西洞庭湖、南洞庭湖则以Ca-P为主,大通湖以Fe/Al-P为主。Ca-P与Fe/Al-P呈现较显著的负相关关系。大通湖释放风险较大,可释放量大;东洞庭湖有一定的可释放量,应对这两个湖泊给予较多的关注。与国内其他湖泊比较,洞庭湖沉积物中TP处于中下水平,IP在沉积物中占据较高比例。湖区沉积物中Fe/Al-P与水体中DIP、DTP、TP均具有较显著的负相关关系,存在磷的内源释放。     

湖水-沉积物界面内源物质交换动态复水模拟研究

分布式采集了玄武湖底长期暴露的底泥,分析了底泥营养物的分层分布及其理化特性对湖泊水质的影响强度。通过动态换水试验,研究了复水过程中暴露底泥营养盐的释放过程和上覆水总磷、总氮浓度变化对水土界面物质交换的作用关系以及对水体富营养化程度的影响机制。实验及模拟表明:由于湖泥表层长期暴露,有机及结合态营养盐降解为无机态营养盐,即使复水过程中使用清水,但由于干涸湖床沉积物总磷T-P、总氮T-N的垂直分布,也将严重导致内源营养盐释放总量持续增加,在相对长时间内,上覆水总磷浓度仍维持在较高(01mg/L)水平。研究成果为实施生态修复,治理复水后湖体富营养化提供了理论和实验依据。     

天然矿物材料修复富营养化水体的实验研究

采用底泥掩蔽技术，选取天然红土，添加适量的粉煤灰及石灰粉作为掩蔽覆盖物，对滇池富营养化水体进行现场修复实验。结果表明：用天然矿物材料减小底泥内源营养盐负荷的释放修复富营养化水体的效果良好；红土是有效的底泥覆盖材料，添加粉煤灰和石灰粉有助于消减底泥中TP、TN的释放量，还可提高对藻类等浮游植物繁殖的营养基础和对藻、藻细胞及其胚胎上浮生长的控制效率，最终达到除藻的目的，为滇池及类似湖库富营养化水体的修复提供了崭新的思路。     

我国河流湖泊污染的防治技术及发展趋势

我国河流湖泊污染现状为V类和劣V类水质占七大水系(辽河、海河、淮河、黄河、松花江、珠江、长江)主要断面的50%以上,高中营养化湖泊占被调查湖泊的85%以上,河流湖泊污染状况十分严峻.目前河流湖泊采取的污染防治技术措施主要有:削减截流污染源、完善城市排水系统和建设污水处理厂、河流低泥疏浚、河道曝气技术、生物修复技术、水生植被恢复工程、引清冲淡等等.生物生态技术将在河流湖泊污染防治及生态恢复中发挥重要的作用.     

Comparison between the lower Nansi Lake and its inflow rivers in sedimentary phosphorus fractions and phosphorus adsorption characteristics

There were many differences between rivers and lakes such as flow velocity, hydraulic retention time, water vegetation community and other chemical-physical factors that may lead to different characteristics of sedimentary phosphorus. In our research, sedimentary phosphorus fractions and its phosphorus adsorption differences between the lower Nansi Lake and its main inflow rivers were compared. The results showed that the contents of NaOH-P, Org-P, IP-P, and TP in lake sediments were obviously higher than those in its inflow river sediments while HCl-P had no obvious difference between them. Based on analysis, the unstable NaOH-P would accumulate in lake sediments, while it is difficult for it to retain in sediments of rivers because of a high frequency of flood flows and unstable bed sediments. In addition, water vegetation communities were helpful in the accumulation of Org-P in lake sediments. From phosphorus adsorption experiments results, the Ceqc (equilibrium concentration of phosphorus release/adsorption) of lake sediments was higher than that of river sediments. It was indicated that sedimentary phosphorus would be more easily released from lake sediments than river sediments. So in future more work should be focused on internal P loading from lake sediments release.     

Hydrobios and Control of Eutrophication in Dongping Lake, Shandong Province

The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake.     

滇池湖泊磷负荷及其对水环境的影响

磷是滇池湖泊富营养化的限制性营养元素。滇池湖泊磷负荷来源一般可分为外环境发生源输入的磷负荷和内环境发生源输出的磷负荷两大类。累积在滇池湖泊内的磷,主要分布在水体与底部沉积物中,滇池湖泊水体中总磷浓度由北向南含量降低,底部沉积物中P2O5含量分布由北向南呈递增趋势。底部0-3m的沉积物P2O5含量由上至下呈明显递减趋势,表明滇池湖泊磷负荷逐年加重。近几年资料显示滇池湖泊单位面积磷负荷达1.52g/m2·a,超过总磷公认允许负荷量中危险值的11.7倍,滇池已成为富营养型湖泊。控制滇池富营养化,在解决入湖磷外负荷的同时,对湖泊底部沉积物中磷内负荷也应予以高度重视。     

Phosphorus Mobilization at the Sediment–Water Interface in Softwater Shield Lakes: the Role of Organic Carbon and Metal Oxyhydroxides

The adsorption of phosphorus on natural diagenetic iron (Feox) and manganese (Mnox) oxyhydroxides was studied in deep and littoral zone sediments of mesotrophic Lac Saint-Charles (46°56 N, 71°23 W), using a Teflon sheet technique for collecting diagenetically produced metal oxyhydroxides. Collected metal oxide amounts were greater at the deep-water station, relative to littoral zone stations reflecting sediment and local diagenetic differences. Two-layer surface complexation modeling on iron oxyhydroxide was consistent with the measured total P/Fe molar ratios except for the upper mixed Mn–Fe oxide layer from the littoral stations, where measured phosphorus exceeded the modeled phosphorus by more than fivefold. Soluble reactive phosphorus (SRP) exchange between oxyhydroxide samples and natural lake water in the laboratory revealed a labile phosphorus pool. Phosphorus determined on the Teflon sheets from the littoral zone stations appears to be related to a distinct non-humic organic carbon pool that readily exchanges SRP, while little exchange was observed from material collected from the deep-water station. We suggest that the enhanced SRP release from littoral zone sediments is due to an organic carbon and/or metal oxide-impoverished sediment matrix, limiting microbial oxide reduction and allowing phosphorus to be rapidly recycled at the sediment–water interface, instead of being slowly incorporated into humic material. The SRP fluxes revealed in our study, which originate from the solid phase at the sediment–water interface, would be difficult to resolve using interstitial pore-water samplers and might be a quantitatively important source of inorganic phosphorus in Shield lakes.     

密云水库沉积物中磷释放的环境因子影响实验

为了探讨密云水库沉积物中磷的释放条件,在实验室模拟了改变溶解氧浓度、调节pH、温度等因素对磷释放的影响实验。结果表明:厌氧条件下沉积物中释放磷的总量是好氧条件下的10倍;上覆水pH值升高有利于沉积物中磷的释放;温度升高,沉积物中磷的释放强度随之增大。同时说明了水库内源性磷对水库水质存在着潜在威胁,为研究水库内源性磷对水质的影响和对水库富营养化趋势的预测提供了可靠的依据。     

黑色岩型铂族矿物中铂钯金相态ICP-MS分析方法研究

黑色岩是近年发现的铂族元素重要载体,由于其金属来源的多样性及成矿作用的复杂性,对于铂族元素在该类矿物中的分布及富集形式目前并不十分清楚,这也是造成黑色岩中铂族元素测定不稳定的主要原因。本文根据黑色岩的矿物性质及组成,将黑色岩中Pt、Pd、Au的赋存状态划分为:可交换相、有机结合相、硫化物结合相、残渣相。通过应用硫氰酸钾+氰化钠作为解吸剂,有效抑制了黑色岩中有机碳对各相态中Pt、Pd、Au的吸附,采用分离富集ICP-MS法测定了Pt、Pd、Au在各相态中的分布。结果表明:(1)各元素各相态的提取总量与该元素在样品中的总量之比分别为Pt 94.4%~101.0%,Pd 95.8%~101.0%,Au 96.7%~102.0%,说明本方法具有较好的准确性和重现性;(2)黑色岩矿物中Pt、Pd、Au的富集不仅具备亲硫性,而且与有机碳形成的地质条件、地质背景有明显的相关性,此结果为研究黑色岩中铂族元素所处的地球化学环境及其成矿规律提供了重要信息。     

Phosphorus fractions and bioavailability in relation to particle size characteristics in sediments from Lake Hongfeng, Southwest China

Information on the chemical composition of phosphorus (P) fractions in sediments is fundamental to understanding P bioavailability and eutrophication in lake ecosystems. Phosphorus fractions and its bioavailability in sediments cores of Lake Hongfeng, southwest China, were investigated using a chemical sequential extraction scheme. Relationships between P fractions, P bioavailability and particle sizes were discussed. P fractions concentrations were ranked in the order: Residual-P > NaOH–rP > NaOH–NRP > HCl–P > BD–P > NH₄Cl–P, and all of them decreased with increasing sediment depth. Statistical analysis showed that concentrations of bioavailable P (BAP) which includes the NH₄Cl–P, BD–P, NaOH–rP and NaOH–NRP fractions ranged from 404.68 to 1,591.99 mg/kg and accounted for 26.8–71.8 % of the concentrations of total phosphorus (TP) in the top 5 cm sediments, whereas in the whole sediment cores, their concentrations ranged from 239.70 to 1,591.99 mg/kg and accounted for 26.8–76.0 % of TP. The results suggested that the sediments were a large potential source of P for algae blooms in Lake Hongfeng. Phosphorus fractions and their potential bioavailability were influenced by the sediment particle sizes, especially the bioavailability of the NH₄Cl–P fraction, which was strongly affected by the presence of fine particle sizes in the sediments.     

Distribution and isotopic composition of sulfur in lake sediments of northern Ontario

Sediments from unpolluted and highly polluted lakes in northern Ontario have been fractionated into acid volatile sulfide, HCl-soluble sulfur, elemental sulfur, pyrite sulfur, ester sulfate and carbon-bonded sulfur and the isotopic composition of each fraction determined. In general, reduced inorganic S constitutes 25–50% of the total S in the polluted surficial sediments, but is <20% in the unpolluted samples, with pyrite formation being a minor process of S diagenesis in lake sediment ecosystems. Organic S in the form of ester sulfate and carbon-bonded S predominates and both the C/S ratios and the isotopic data suggest that, in unpolluted lakes, plant detritus can be a major contributor of organic-S to the sediments. The depth profiles observed suggest that the more labile ester sulfate is diagenetically converted to the carbon-bonded form. For the polluted sediments from the Sudbury basin, the isotopic data suggest that (a) the elemental S is derived from the oxidation of acid volatile sulfide in the aerobic surficial sediments, and (b) the isotopically light reduced S species are incorporated into the organic material. S diagenesis in lake sediments generally results in the release of ³⁴S to the overlying water. The suggestion is made that sulfate concentrations over 5 mg/1 accompanied by an enrichment of surficial sediments with isotopically different S may signal significant inputs of pollutant S into the lake and its basin.