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持久性有机污染物在中国湖泊生物中分布与富集的研究进展 总被引：2，自引：2，他引：0
持久性有机污染物(POPs)在环境中分布广泛且持久存在并具有高生物富集性,通常具有致癌、致畸、致突变等危害.湖泊是POPs的主要环境归宿之一,湖泊中的POPs可被水生生物富集并通过食物网传递,对生态系统及人体健康构成极大的危害.中国是POPs生产及使用大国,也是世界上湖泊较多的国家之一.湖泊生物尤其是水产品是中国人饮食中的重要组成部分,因此POPs在中国湖泊生物体中的富集对当地的生态系统和人体健康存在很大的潜在危害.本文通过收集、分析1997年—2017年7月公开发表的中国湖泊生物体POPs数据,发现中国湖泊生物中POPs富集研究主要集中在东部平原湖区,青藏高原及云贵高原湖区有少量研究;不同POPs在不同湖区湖泊生物中富集的含量存在较大差异,DDTs和HCHs在各湖区生物中普遍检出且存在明显差异,东部平原湖区生物体内多氯联苯、多溴联苯醚含量高于其他湖区生物体内含量,其他POPs在湖泊生物体内的富集研究相对较少且主要集中在东部湖泊.中国湖泊生物中DDTs、HCHs、多环芳烃、多氯联苯、多溴联苯醚、多氯苯并二英和多氯苯并呋喃、全氟化合物、全氟辛酸、有机锡及六溴环十二烷脂肪归一化后的平均含量分别为454.56±653.40、153.57±435.99、2849.49±3092.52、118.40±20.28、18.40±20.28、17.43±19.43、147.17±192.93、1542.18±1347.64、11380.75±5316.75和2.19±1.92 ng/g.POPs在中国湖泊生物体内的含量水平与生物所处营养级、脂肪含量和年龄呈正相关,但并非完全一致,还受到生活习性、生物物种与结构、生存环境及生物量等多种因素的影响;生物不同组织对POPs的富集能力有较大差异,内脏器官对POPs的富集能力明显高于肌肉组织. 相似文献
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紫阳黄柏树湾和竹山文峪河毒重石矿床碳、氧及硼同位素研究 总被引：4，自引：0，他引：4
紫阳黄柏树湾毒重石矿床和竹山文峪河毒重石-重晶石矿床呈层状或似层状产于下寒武统下部的硅质岩中, 矿体受岩性和岩相控制明显. 矿床中毒重石、钡解石和方解石的硼同位素及碳、氧同位素研究结果表明, 形成这些矿物的碳主要来自沉积物中的生物有机质在早期成岩阶段经降解、缩合及脱羧基作用所形成的烃类物质或生物气; 而硼主要为孔隙水中硼与有机质降解过程中所释放的硼的混合, 少部分硼来自盆地深部循环热卤水. 硼同位素及碳、氧同位素研究结果一致表明, 毒重石沉淀于早期成岩阶段富含有机碳的孔隙水介质中. 毒重石矿石中广泛发育的生屑及粒屑结构说明生物作用通过生物成因重晶石(Bio-barite)的形式将海水中的Ba2+浓集并沉降于海底, 形成钡矿床的初始富集体. 海水中生物作用和沉积物的早期成岩作用是形成本区毒重石矿床的主要成矿机制. 相似文献
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重点阐述了生物表面活性剂清洗土壤有机污染物的机理及影响因素。根据国内外最新文献．对使用生物表面活性剂溶液修复有机物污染土壤的研究进展进行了综述。并展望了生物表面活性剂在清洗土壤有机污染物中的研究前景。 相似文献
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环境中的氯苯甲醚类化合物(chloroanisoles,CAs)主要来自于氯酚类化合物及其他结构相似的氯代烃.在我国洞庭湖血吸虫疫区,五氯酚作为灭螺剂施放对周围环境造成了CAs污染.运用气相色谱质谱联用方法测定洞庭湖支流(澧水、藕池河和沱江)表层水和沉积物中的CAs,并分析其分布特征与生态风险.结果显示:(1)水体是CAs的主要赋存介质.三支流表层水中CAs体现出显著差异性,污染水平由大到小为澧水藕池河沱江,三者总CAs浓度分别为18.94、8.83和4.14 ng/L;在3支流中沉积物中的总CAs无明显差异,分别为2.86、3.61和4.07 ng/g.(2)澧水表层水和沉积物中高氯取代CAs(三氯苯甲醚、四氯苯甲醚和五氯苯甲醚)为主要污染物(分别占73.75%和68.89%);藕池河表层水中低氯取代CAs(一氯苯甲醚和二氯苯甲醚)占比相对较高(48.59%),而沉积物中以高氯取代CAs为主(93.38%);沱江表层水和沉积物中占比较高的CAs为一氯苯甲醚,分别占28.26%和75.56%.(3)空间分布上,从上游到下游澧水表层水中CAs浓度呈现波动下降的趋势,而沉积物中呈上升趋势;藕池河表层水中CAs呈现波动下降的趋势,沉积物中无明显变化趋势;沱江表层水和沉积物中一氯苯甲醚呈波动上升趋势,其他CAs有波动但无明显趋势.(4)研究区水中的五氯苯甲醚浓度远低于报道的鱼类和无脊椎动物的五氯苯甲醚急性半数致死浓度,目前不会对水生生物造成太大影响,但其对人类健康和环境的潜在风险不可忽视. 相似文献
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生物处理是一种经济有效处理土壤水环境中有机污染物的手段,本文在研究土地生物处理过程的基础上,建立了综合描述有机污染物在土壤－水－微生物系统中扩散、吸附／解吸、屏蔽和生物降解过程的数学模型。为确定模型中各参数在模型计算中的作用和相对重要性,进行了参数灵敏度分析,预计数学模型可以定量预测有机污染物进行土地生物处理所需的要时间和程度,为构建土地生物处理工程提供参考。 相似文献
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太湖流域滆湖底泥重金属赋存特征及其生物有效性 总被引：1，自引：0，他引：1
为了探讨太湖流域滆湖底泥重金属(Cd、Cr、Cu、Zn、Ni和Pb)的赋存特征及其生物有效性,对底泥重金属总量、形态以及生物富集量进行了分析.结果表明,6种重金属含量的空间分布表现为北部湖区最高,其次为南部湖区,中部湖区最低,重金属Ni、Cu、Zn和Pb含量显著高于沉积物背景值,分别是背景值的4.77、3.89、2.96和2.76倍,重金属总量与沉积物中的黏土成分含量具有显著相关性.采用三级四部提取法对重金属形态进行分析表明,6种重金属的生物有效态(弱酸结合态、可还原态和可氧化态之和)含量顺序为CdCuZnPbNiCr,其中Cd、Cu、Zn和Pb的生物有效态含量分别占总量的84.15%、78.47%、76.50%和64.29%.Cu和Zn在铜锈环棱螺中富集含量要显著高于其他金属元素.相关性分析表明,6种重金属中仅Cr和Pb的生物富集量与有效态含量具有显著相关性,这表明,重金属在生物体内的富集不仅与有效态含量有关,还与底泥重金属总量有关.因此,评价滆湖重金属的生态风险时需要综合考虑重金属的总量及生物有效态含量. 相似文献
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富营养化湖泊的藻类残体大量沉降到湖底,其中易降解成分的降解和转化快速消耗底层水体中的溶解氧,极易造成水土界面缺氧,影响湖泊生态系统的健康.于2014年对巢湖12个样点的表层沉积物进行周年跟踪研究,分析样品中有机质来源、总有机碳(TOC)、蛋白质、总糖、总脂以及生物聚合物碳(BPC)等成分含量,揭示易降解有机质的成分特征及在巢湖的分布规律.研究表明:巢湖表层沉积物TOC含量较高,全湖样点平均含量达到1.24%.BPC含量占TOC含量的30.99%~60.48%,有机质中易降解成分含量较高,并且在冬季和夏季时在巢湖西北部湖区有明显累积;有机质及其中的生物易降解部分均主要集中在粒径4~8μm的表层沉积物上,在应用工程技术手段处理、降解表层沉积物中的过量有机质时,更应该关注粒径为4~8μm的沉积物颗粒. 相似文献
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水闸建设对河流产生阻隔作用，改变了河段水流形态，污染物输运及水质时空分布也随之发生改变，进而可能对水环境容量产生影响。本研究以拉萨河城区段为研究对象，考虑水闸建设对水动力学条件的影响，在利用平面二维模型进行水动力-水质模拟的基础上，计算分析了水闸建设前、后COD的水环境容量，探讨了连续水闸建设对河流水环境容量的影响。研究成果表明，水闸修建对水环境容量的影响主要有两个方面：一是水闸蓄水后，水体由流动转变为相对静止的状态，闸前水流流速减缓，水深增加，影响污染物的扩散，降低污染物降解系数，进而影响污染物降解过程；二是水闸蓄水会使污染物在库区滞留，使污染物滞留时间增加，从而提高污染物的降解量。拉萨河水闸修建后，因水闸蓄水影响，流速减缓，污染物向河道中央扩散受阻，易聚集于排污侧；与天然河道相比，蓄水区河段平均流速由0.34 m/s下降至0.10m/s，平均水深由0.6 m增大至2.0 m,COD降解系数由0.12 d-1下降至0.04 d-1，下降约67%，污染物滞留时间增大为原来的3倍左右。计算结果表明，在两种影响的综合作用下，1个水闸使研究河段CO... 相似文献
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人工湿地废水处理系统的生物学基础研究进展 总被引：45，自引：3，他引：45
主要阐述了人工湿地废水处理系统中生物学基础的研究进展，至今，对作为湿地生产者的水生植物研究较多，水生植物除直接吸收利用废水中的营养物质，吸附和富集重金属外，还起输送氧气至根区，形成根区多种微环境和维护湿地水力传输的作用；而对作为湿地分解者的微生物的研究较少，湿地微生物的代谢活动是废水中有机物质降解的基础机制。 相似文献
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The bile liquid is preserved with ethanol and the protein is precipitated. Prefractionating is done by liquid-liquid extraction by chloroform and ethyl acetate. The extracts are column-chromatographically separated on Florisil and subsequently detected by thin-layer chromatography. For determining the identity of substances, the penta fluorobenzyl derivatives are prepared and chromatographed under the same conditions. Detection is carried out with the aid of ammoniacal silver nitrate reagency and ultraviolet irradiation. The highly polar conjugates of chlorophenoxyalkane acids and chlorophenols which are present in the bile are cracked by acid hydrolysis and then cleaned by re-extraction. In this way, 2, 4-D, MCPA, MCPP, 2,4-dichlorophenol and 2-methyl-4-chlorophenol were detected from Salmo gairdneri. 6… 21 d after the application of the herbicides in the catchment area their concentration in the fish bile amounted to about 200 mg/l, 90% of them having been conjugates. Thus, the biliary excretion of xenobiotic substances offers an important new aspect of biomonitoring by means of fish tests, especially in the range of subacute and chronic toxicity. 相似文献
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Oxygen-enhanced biodegradation of phenoxy acids in ground water at contaminated sites 总被引：1，自引：0，他引：1
The effects of adding oxygen to anaerobic aquifer materials on biodegradation of phenoxy acid herbicides were studied by laboratory experiments with aquifer material from two contaminated sites (a former agricultural machinery service and an old landfill). At both sites, the primary pollutants were phenoxy acids and related chlorophenols. It was found that addition of oxygen enhanced degradation of the six original phenoxy acids and six original chlorophenols. Inverse modeling on 14C 4-chloro-2-methylphenoxypropanoic acid (MCPP) degradation curves revealed that increasing the oxygen concentrations from <0.3 mg/L up to 7 to 8 mg/L shortened the lag phases (from approximately 150 d to 5 to 25 d) and increased first-order degradation rate constants by 1 order of magnitude (from approximately 5 x 10(-2) d(-1) to up to 30 x 10(-2) d(-1)). Additionally, the degree of MCPP mineralization was increased (30% to 50% mineralized at low oxygen concentrations and 50% to 70% mineralized at high oxygen concentrations, based on 14CO2 recovery). These positive effects on degradation were observed even at relatively low oxygen concentrations (2 mg/L). Furthermore, effects related to the addition of oxygen on the general geochemistry were studied. An oxygen consumption of 2.2 to 2.6 mg O2/g dw was observed due to oxidation of solid organic matter and, to some extent (0.5% to 11% of the total oxygen consumption), water-soluble compounds such as Fe2+, dissolved Mn, nonvolatile organic carbon, and NH4+. Overall, the results suggest that stimulated biodegradation by addition of oxygen might be a feasible remediation technology at herbicide-contaminated sites, although oxygen consumption by the sediment could limit the applicability. 相似文献
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E.V. Taguas 《地球表面变化过程与地形》2021,46(4):744-757
Concentrated flow erosion in Mediterranean cultivated areas is considered a major process of land degradation. Rills and ephemeral gullies in a 6.4 ha olive orchard catchment located in an intensive commercial farm, which could represent a common degradation scenario in hilly areas, were measured and compared with the sediment loads at the outlet. Four GPS survey campaigns were carried out between March 2009 and March 2014, for periods with cumulative precipitation ranging between 728 and 121 mm. Chopped pruning residues were kept on the lanes during campaigns 2–4, whereas a grass cover crop was seeded in campaign 4. Rainfall, runoff and sediment loads were measured in a flume gauge station at the catchment outlet. The ratio of concentrated flow erosion to catchment sediment load varied between 1.0 and 35.0. Total concentrated flow erosion ranged between 25.0 and 0.1 t ha−1. Rill erosion was the dominant process on ephemeral gullies for three campaigns, with a mean contribution to the total concentrated flow erosion of 55%. Rills clearly followed tractor tracks along the most parallel lanes to the maximum slope. Therefore, a change in traffic direction would be helpful to reduce the connectivity, controlled by the spatial distribution of rows and lanes in the farm. Olive plantation distributions should prioritize hydrological criteria to adapt traffic patterns in olive farms, as long as the tractor manoeuvrability and risk of overturning are not adversely affected. Although the farmer only kept the cover crop for one campaign, it proved to be an efficient measure for interrupting rills along the lanes, whereas pruning residues were effective for the control of interrill erosion. On-site application of pruning residues reduced their handling and transport costs, while increasing the soil fertility and soil cover. However, guidelines for the efficient application of pruning residues are still necessary in terms of residue rates and orientation. 相似文献
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Wido Schmidt 《洁净——土壤、空气、水》2004,32(1):48-60
Chlorine dioxide stock solutions for the disinfection of drinking water are made by the application of chlorite/chlorine process in many waterworks. In such cases the stock solution is always characterised by a mixture of chlorine and chlorine dioxide. The disinfection of waters of different origin with a mixture of chlorine dioxide and chlorine showed the formation of odours of different intensity. The reasons are the re‐formation of chlorine dioxide and the formation of odorous disinfection by‐products. Applying the chlorine dioxide for disinfection, its re‐formation caused by the reaction of chlorite with chlorine is the dominant reason of odour formation. When chlorine is used, the formation of odorous by‐products becomes more relevant. In order to quantify the sensitivity of water concerning odour, the odour indicator coefficient OI was defined. The decreased demand of chlorine dioxide by applying chlorine and chlorine dioxide in combination is recognised to be the key in order to avoid the formation of odour after the disinfection of drinking water with chlorine dioxide. 相似文献
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《Ground Water Monitoring & Remediation》1988,8(1):88-92
The effect of chlorine concentration, ground water pH, and contact time on chlorine demand and the inactivation of coliform bacteria, Escherichia coli , was studied in the laboratory using a batch reactor under controlled environmental conditions. Ground water for this study was obtained from 200m deep wells in Bangkok, Thailand. The test results demonstrate that the kinetics of chlorine inactivation of coliforms in ground water consist of an initial rapid kill rate followed by a slower rate. Disinfection was more effective in acidic pH (5.5) than basic pH (8.5). Chlorine demand exerted by ground water increased with chlorine dose, contact time, and hydrogen ion concentration. Based on the applied chlorine dose, inactivation of E. coli by chlorine at neutral pH and room temperature was over two orders of magnitude less effective in ground water than in demand-free water. Because of the high chlorine demand exerted by this ground water, chlorine residuals leaving the treatment plant are likely to be unstable. 相似文献
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A demonstration plant for biological heterotrophic water treatment of nitrate polluted groundwater has been operated in Coswig near Dresden since 1989. In this NEBIO tube reactor process the denitrification is achieved in a downstream fluidized bed with continuous regeneration of sintered polystyrene particles as inert carrier material. A nutrient consisting of ethanol and phosphate is dosed in the reactor influent. In the subsequent treatment stages the denitrified water is aerated, filtered through a multilayer and GAC filter, and is finally disinfected with chlorine gas. The influence of changing raw water quality (oxygen content, pH value) on the process performance was examined. Increasing oxygen concentration lowers the nitrate reduction potential and rises the consumptive ratio ΔC/ΔNO3. The technology shows a high removal performance of 270 g NO3 m?3 h?1 in the range of pH 6.2 to pH 7.3 which is typical for natural groundwaters. The degradation of nitrate is increasingly inhibited for pH values beyond 7.6. Nitrite production occurs significantly in high pH ranges. The results lead to further insight in the stoichiometry of heterotrophic denitrification. By expressing the stoichiometric equations for nitrate and oxygen respiration as functions of oxygen and pH value it could be shown that the influent water quality has strong effects on the consumption of ethanol. A kinetic model was developed to predict the reactor performance under changing raw water conditions. A two stage kinetic model was designed, regarding two main effects: biochemical degradation of oxygen, nitrate and ethanol and distribution of active biomass due to hydraulic properties of the tube reactor. This model may be helpful for reactor design for sites of various ground water qualities. 相似文献
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Yi‐Che Hsu Yu‐Hsuan Wang Shuo‐Chuan Wu Chuen‐Mei Wu Ching‐Ping Chu Yu‐Jen Chung Yong‐Tang Huang Kuo‐Liang Wang 《洁净——土壤、空气、水》2012,40(3):254-261
Feasibility of effluent reclamation for the Futian municipal WWTP in Taichung Taiwan was evaluated using an “SF‐UF‐RO” pilot plant. The optimal parameters of each unit were obtained during the pilot plant test. The pilot plant started the operation in late October 2008 and operated until January 2011. The reverse osmosis (RO) system produces 75 m3 water daily, and the produced water quality was comparable to the city water in Taichung. Chlorine dosed in the sand filtration (SF) inlet and ultrafiltration (UF) backwash had the most significant effect on the stability of system performance. When the chlorine was underdosed, biofilm clogged the bag filter (prefilter of UF) and led to the flow rate decay of the UF. The prefilter needed replacement every 1 or 2 weeks resulting in increased process cost. On the other hand, when the chlorine dosage was increased to mitigate the biofilm growth, the residual chlorine not only reacted with TOC and derived trihalomethanes (THMs) in the RO product water (more than 20 µg/L), but it also damaged the RO membrane. After trial and error, the chlorine concentration was optimized as 0.7 mg/L in SF inlet to prevent growth of biofilm as well as to control the residual chlorine in the RO inlet and THMs in the RO product water. It is suggested that cautiously adjusting chlorine dosage is essential for stably operating such a hybrid membrane system to reclaim the municipal wastewater. 相似文献
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Ecological base line states for fish communities are necessary for the evaluation of ecological integrity. In Austria the fish communities of all the larger lakes are strongly influenced by human activities, like commercial fisheries, fish stocking, eutrophication or shore line degradation, and therefore these baseline states can not be developed by comparison with a natural, undisturbed lake. We developed ecological baseline states for the fish communities of the lakes Hallstättersee, Traunsee, Mondsee, Irrsee and Wallersee by reconstructing the native fish communities of these lakes from historical documents (from between 1500 to 1940). Then we classified the potential fish species of these lakes according to their ecological requirements. Finally we developed the base line states with 16 different ecological factors similar to the factors used for the ecological integrity assessment procedure for streams.
The process of reconstructing the fish communities and some advantages and disadvantages of the base line states for fish communities are discussed. 相似文献
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供给侧改革与科技创新耦合助推西藏渔业资源养护 总被引：4，自引：0，他引：4
由于西藏生态环境脆弱、生态系统结构简单、生产力低下以及高原鱼类生长缓慢、资源补充周期长、对生境高度适应和依赖等特点,高原水域水生生态更容易受到外界的影响.尤其近几十年以来,外来鱼类入侵、水电水利设施的兴建、过度捕捞、水质环境恶化,导致162种青藏高原鱼类中,处于极危、濒危、易危或野外绝灭鱼类就有35种,超过了20%,在雅鲁藏布江中游,常见的6种裂腹鱼类中,有3种鱼类处于濒危状态,因此推动西藏渔业资源养护刻不容缓.供给侧改革和科技创新,将为西藏渔业资源养护注入新的活力.通过科学引导放生行为,规范和加强增殖放流行为,积累和推广本土鱼类繁育技术,密切关注西藏水生态系统,将会推动西藏渔业资源养护工作迈上一个新台阶,也会助推西藏"精准扶贫"进程. 相似文献