Effect of pollution on the blood characteristics ofTilapia zillii G.

Lake Mariut, a shallow brackish water basin near Alexandria, was a highly productive lake; however, it now receives large quantities of pollutants. The amount of DO has been greatly reduced.Tilapia zillii G. have been studied to determine the modification of blood characteristics. In O₂ deficient areas of Lake Mariut the fish undergo asphyxiation.     

MAN-MADE IMPACT ON THE GEOCHEMISTRY OF THE NILE DELTA LAKES. A STUDY OF METALS CONCENTRATIONS IN SEDIMENTS

Forty two sediment samples were collected from four River Nile northern delta lakes (Mariut, Edku, Burullus and Manzalah) to asses the man-made impact on their environment during the last 20 years. Due to the continuous discharge of agricultural, industrial and sewage waste waters to these lakes, significant variations in the sediment's nature took place, with fine fractions dominating opposite to the outflowing area of the main drains. Organic carbon was elevated at the southern regions, reaching 10.5 ± 4.5% in lake Mariut. Meanwhile, carbonate increased reaching 90% for samples collected at the lake-sea connection areas. The 0.5 N HCl extractable metals indicated enriched levels of different metals at sites affected by sewage and industrial discharge. This fraction constituted 75 and 81% of the total metals in Lakes Mariut and Manzalah, respectively. Extractable Cd for Lakes Mariut and Manzalah constituted 51 and 53%, respectively, while Pb formed 59% of the total digestable metal in Lake Manzalah. Total metals concentrations especially Cd and Pb were elevated 8 to 70 times than those observed in the same lakes 25 years ago. The conversion of the untreated sewage discharge of Alexandria city to Lake Mariut and significant portion of Cairo sewage to Lake Manzalah during the past 10 years lead to the appearance of elevated levels of contaminants in both lakes. Agricultural discharge showed less impact on Lakes Edku and Burullus. Cluster analysis revealed associations between stations located under same types of stress while the correspondence factor analysis displayed that metals distribution pattern in the Nile delta lakes are governed by organic carbon as well as fine grained size fraction distribution.     

Metals and chlorinated hydrocarbons in surficial sediments of three nile Delta lakes,Egypt

Water, Air, & Soil Pollution - Surficial sediment samples from three shallow Nile Delta lakes (Lake Mariut, Hozha hydrodrome, andke Manzalah) were analyzed for PCBs, DDT-group pesticides, and...     

Occurrence and distribution of chemical pollutants in Lake Mariut,Egypt. II. Heavy metals

The occurrence and distribution of heavy metals in the water of Lake Mariut, a heavily polluted brackish water lake in Egypt, and their accumulation in the different parts ofTilapia fish in this lake were studied. The variations in concentrations of the metals (Zn, Cu, Fe, Mn, and Cd) in the lake water are mostly due to variations in the discharge rate of dumped wastes. The mean concentrations of these metals in different fish parts were much higher than those in the lake water.     

Occurrence and distribution of chemical pollutants in Lake Mariut,Egypt

Occurrence and distribution of organochlorine pesticides in the water of Lake Mariut, a brackish coastal Egyptian lake suffering from pollution, and their accumulation in the common fish Tilapia were studied. The major pesticides detected in the lake water were lindane, p,p′-DDE, o,p′-DDT, and p,p′-DDT. These compounds, except o,p′-DDT, were detected in the fish samples in exceedingly higher concentrations compared with those found in the lake water.     

Differentiation of soil fauna in desert agriculture of the Mariut region

Summary The soil fauna of 23 sites in the Mariut region, west of Alexandria, Egypt, was sampled monthly or seasonally for periods of 1,5–2.5 years. These sites range from unutilized littoral sand dunes, to free-grazing pasture, to low- and high-intensity dry farming, to irrigated agriculture. The average population densities of the encountered taxa were compared by corresponding analysis and by ascending hierarchic classification. With intensification of the agricultural practices, true detritivores of the original system, capable of dealing with the available plant and animal litter and adapted to the harsh desert climate, are replaced by other mesic detritivores adapted to the changes in litter quality (less animal and more plant) and also adapted to the new physical and chemical soil conditions. Meanwhile, the increase in plant biomass encourages the appearance and proliferation of cryptic phytophages (agricultural pests), occupying the niche of the removed large (domestic) herbivores. Carnivores (e.g.Carabidae) also change accordingly. Sites can thus be characterized on the basis of their soil faunas, according to the stage of their evolution, and a system of exchange of missing key taxa between sites should be established.     

PCR扩增法检测江苏省5大淡水湖泊产毒微囊藻的空间分布

微囊藻毒素（Microcystin,MC）的产生受微囊藻毒素合成酶基因簇（microcystin biosynthesis gene,mcy）调控,常用PCR扩增mcy基因检测产毒微囊藻。采集江苏省5大淡水湖泊——太湖、滆湖、高宝-邵伯湖、洪泽湖和骆马湖的水样,测定水体营养盐浓度和叶绿素a浓度,根据叶绿素a浓度计算5个湖泊的富营养化指数（Trophic state index,TSI）,同时应用单一和多重PCR扩增mcy基因。结果表明,太湖和滆湖处于富营养和超富营养化水平,洪泽湖和骆马湖处于中营养和富营养化水平,高宝-邵伯湖处于寡营养水平。太湖、滆湖、洪泽湖和骆马湖的所有水样均检出mcy基因,4个湖泊水体受到微囊藻毒素的潜在威胁,高宝-邵伯湖没有检测出mcy基因的存在,尚未受微囊藻毒素的污染。     

藻华暴发期太湖不同湖区水样对斑马鱼胚胎发育及仔鱼生长毒性研究

为了评价太湖蓝藻暴发对生态系统的危害程度,于蓝藻水华暴发的2009年7月在太湖梅梁湾（M1和M2）、湖心区（H）和胥口湾（X）4个点采集水样,将斑马鱼（Danio rerio）胚胎直接暴露于水样中,研究太湖不同湖区水质对斑马鱼胚胎发育和仔鱼生长的影响。结果表明,暴露于梅梁湾M2点的斑马鱼胚胎畸形率为7%,显著高于空白组（K）（P〈0.01）,湖心H和梅梁湾M1点为5%左右,也高于空白组（P〈0.01）,而胥口湾X点和空白组无显著性差别（P〉0.05）。蓝藻暴发水体对斑马鱼胚胎产生致畸作用,表现为脊椎弯曲、尾部弯曲和心包水肿等。同时,不同湖区水样对仔鱼生存活力指数（SAI）的影响表明,梅梁湾M2点仔鱼活力最弱,胥口湾X点仔鱼活力最强。试验期间梅梁湾M2点蓝藻密度最高,胥口湾最低,太湖蓝藻密度的分布与斑马鱼胚胎发育的畸形频率具高度的一致性。因此,藻华暴发水体会对脊椎动物胚胎发育和仔鱼生长产生不利影响,危害水生态系统的安全。     

青海湖流域土壤保持量动态变化

[目的]对青海湖流域近24a的土壤保持量进行评估,揭示其时空变化规律,为定量评估青海湖流域土壤保持功能和区域土壤保持的重要性提供理论支撑。[方法]利用通用土壤流失方程(USLE)和GIS技术,评估和揭示1987—2010年青海湖流域土壤保持量的时空动态变化。[结果]近24a来青海湖流域土壤保持量平均为4.68×108 t/a;单位面积土壤保持量高值区分布在青海湖流域主要河流的河源区及中部地区,低值区主要集中分布在青海湖周围、河谷以及青海湖流域西北部地区。在各生态系统中,高寒草甸的土壤保持量最大,平均为2.68×108 t/a。近24a来青海湖流域土壤保持量呈先增加后减小的变化趋势,并在2005年达到最大,相比于1987年,2010年其土壤保持总量共计增加了2.17×108 t,其中,高寒草甸的土壤保持量增加最多,增加了1.20×108 t。[结论]近24a来,青海湖流域土壤保持功能在不断增强,土壤侵蚀程度不断减弱,表明青海湖流域的生态环境在不断改善。     

升金湖国家自然保护区土地利用生态风险评价

[目的]为了有效保护升金湖国家自然保护区生态环境。[方法]根据安徽省升金湖国家自然保护区1986,2002和2011年3期TM遥感影像,运用ERDAS,ArcGIS等软件,结合升金湖自然保护区土地利用现状,将升金湖自然保护区试验区、核心区、缓冲区3个功能区的影像进行监督分类,划分成建设用地、草地、耕地、林地、水域、未利用地、交通用地和园地8个地类,并统计各土地利用类型面积。采用层次分析法和模糊数学法建立土地利用生态风险评价模型,计算土地利用生态风险指数。[结果]保护区整体的土地利用生态风险等级为中级,1986—2011年,土地利用生态风险逐渐增强。其中,核心区的土地利用生态风险指数相对较低,但也呈逐渐增强趋势;试验区的土地利用生态风险指数较大,缓冲区的土地利用生态风险指数变化明显,土地利用生态风险较严重。[结论]升金湖自然保护区生态风险呈上升趋势,需要采取措施,建立预警机制,有效控制升金湖的生态风险。     

1951－2015年洞庭湖区旱涝演变及典型年份旱涝急转特征分析

旱涝灾害是制约洞庭湖区经济发展的重要因素,为预测湖区旱涝灾害变化趋势,该文选取1951-2015年洞庭湖区及其周边地区35个气象站点的逐月降水量数据,利用标准化降水指数和夏季长周期旱涝急转指数,辅以小波分析方法,分析近65 a来研究区域的旱涝演变及典型年份旱涝急转特征.结果表明:该区旱涝事件发生的频率高,不同时间尺度旱涝事件发生的平均频率为42.62%.在季节尺度上,夏季洪涝事件发生的频率最高,为33.33%,冬季干旱事件发生的频率最高,为41.54%;在年代际尺度上,20世纪70年代干旱事件发生的频率最高,为25.83%,其次是2001-2015年,频率为22.99%,90年代洪涝事件发生的频率最高,为30%.该区域旱涝变化有4个特征时间尺度,分别为4、10、25和31 a,预测湖区在未来几年降水偏多.洞庭湖区3个区域的旱涝变化大抵一致,但在不同时期仍存在一定的差异.湖区近65 a来有15 a的LDFAI绝对值大于1,旱涝急转现象较频繁,不管是旱涝变化还是旱涝急转变化,东、西洞庭湖区的变化趋于一致,南洞庭湖区与东洞庭湖区旱涝急转变化差异较大.     

近40年鄱阳湖枯水期水体面积变化特征及驱动因素分析

湖泊是维持生态平衡的重要因素,鄱阳湖作为我国最大的淡水湖,由于枯水期提前且持续时间延长导致水体面积发生变化。研究鄱阳湖枯水期水体面积的变化特征及其驱动因素对区域生态环境的稳定及经济发展具有重要意义。利用1973-2018年鄱阳湖枯水期遥感影像数据,采用Mann-Kendall趋势检验法、Mann-Kendall突变分析法及Pettitt突变检验对湖泊水体面积变化特征进行分析,并利用双累积曲线法量化出入湖流量之差和人类活动导致的土地利用的变化对鄱阳湖枯水期水体面积的影响。结果表明:(1)在研究时段内,鄱阳湖枯水期水体面积呈极显著下降趋势(P0.01),突变点年份为2002年(P0.01);(2)出入湖径流量之差多年来呈现不显著的增加趋势;1980-2015年鄱阳湖流域的土地利用情况表现为城乡工建用地增加,其余用地类型均呈现减小趋势;(3)以1977-2002年作为基准期,2003-2016年人类活动导致的土地利用的变化对鄱阳湖枯水期水体面积变化的贡献率为87.48%,是鄱阳湖枯水期水体面积显著减少的主要原因。研究成果为鄱阳湖水资源的合理利用及维持区域生态系统的平衡提供了科学依据。     

基于GIS和RUSLE的滇池流域土壤侵蚀敏感性评价及其空间格局演变

土壤侵蚀是滇池流域重要的生态问题之一,掌握滇池流域土壤侵蚀敏感性的时空变化特征有助于水土保持工作的实施和改进。以降雨量、DEM、土壤类型和Landsat影像为数据源,选择降雨、土壤、坡度坡长、植被覆盖4个因子建立土壤侵蚀敏感性评价体系,对滇池流域进行土壤侵蚀敏感性评价。结果表明:滇池流域土壤侵蚀敏感性以轻度敏感和中度敏感为主。空间分布上,轻度敏感区主要分布在滇池周边。中度敏感区主要分布在滇池流域山地区域,地形陡峭。时间变化上,1999—2014年滇池流域土壤侵蚀敏感程度呈下降趋势。轻度敏感区域面积增加20.18%,中度敏感区域面积减少20.31%,轻度敏感区的增加来源于中度敏感区的转变,转变区域分布于滇池流域西北部和东南部。在土壤侵蚀敏感性影响因子中,降雨是影响滇池流域土壤侵蚀敏感性的关键因子。研究滇池流域土壤敏感性时空变化,识别滇池流域易发生土壤侵蚀的区域,有助于该区域水土保持措施实施、生态治理和土地利用优化。     

内蒙古自治区呼伦湖水质变化特征及其影响因素

[目的]对内蒙古呼伦湖水质变化特征及其影响因素进行分析,为呼伦湖富营养化机理研究提供理论基础。[方法]采用2012—2014年的水质监测数据,对水体中TN,TP和叶绿素a(Chla)浓度的时空分布进行分析,采用综合营养状态指数法对水质进行富营养化评价,并对影响水质变化的因素进行探讨。[结果]在时间上,Chla,TN,TP浓度均表现为:7,8月9月1月;在空间上,TN的浓度的范围为1.70~2.31mg/L,均值为1.94mg/L。TP的浓度的范围为0.15~0.25mg/L,均值为0.19mg/L。呼伦湖水质已经达到地表水环境质量Ⅳ,Ⅴ类水体标准,是磷限制性湖泊。叶绿素a与总氮表现为:西南、东北两端中部,总磷浓度除一个水质观测点较高外,其他各观测点变化不大。呼伦湖水体夏季已经呈现中度富营养化水平,而冬季和秋季呈轻度富营养化水平。[结论]呼伦湖已经处于富营养化状态,丰富的外源输入为非冰封期呼伦湖发生富营养化提供了一定的物质基础。     

滇池流域建设用地景观格局与滇池水质关系分析

运用灰色关联度分析法,研究了高原湖滨区滇池流域建设用地的景观格局指数与滇池水体的TN,TP浓度变化之间的关系。结果表明,1988-2008年,滇池草海与外海TN,TP浓度呈不断上升的趋势;滇池流域建设用地斑块的团聚程度和整合性升高,建设用地斑块间距离变小,大面积的建设用地增多,且建设用地斑块形状趋于复杂,具有不规则的特征;滇池流域建设用地对水质的影响与其景观空间格局关系密切,特别是聚合度和面积加权的平均斑块分维数。要保证该地区迅速发展的城市化背景下的水环境安全,滇池流域土地利用调整的基本方向是在湖滨带地区,保留足够的生态用地,避免建设用地的过度整合及大面积建设用地的形成。     

近500年来骆马湖演变的驱动力探究

[目的]对骆马湖的成因以及影响其演变的驱动因素进行探讨,为该湖泊合理开发以及水资源的可持续利用提供依据。[方法]以近500a来的历史文献数据为基础,辅助以统计学及数字化分析等方式开展研究。[结果]泇运河、中运河等水系的开通促进骆马湖发育与复生;骆马湖淤积年份与黄河泛滥年份有较强的一致性;清嘉庆朝后对骆马湖滩的围垦逐渐加剧;骆马湖区的气候呈干湿交替变化,并在1720—1765年,达到了近500a来最湿润的时期。[结论]流域水文状况变迁与泥沙淤积是影响骆马湖演变的决定性因素;气候因素与湖滩围垦也对骆马湖的演变有一定的影响;骆马湖特殊的社会价值是决定其演变过程的更深层次原因。     

Use of the mercury cycling model (MCM) to predict the fate of mercury in the Great Lakes

In response to U.S. EPA's proposed Great Lakes water quality criteria for mercury (Hg), a fieldvalidated Hg cycling model (MCM) was used to predict Hg levels in the abiotic and biotic components of Lake Superior and Lake Erie. The U.S. EPA criteria are based on water column Hg concentrations and simple trophic level transfer and, thus, do not consider sediment interactions and water chemistry factors. The model, using data from published reports, was run to simulate a 25 year steady state period. For these simulations, methylmercury (MeHg) represented 5% of total Hg in Lake Erie and 8% of total Hg in Lake Superior. These proportions are roughly 3–5 times lower than U.S. EPA's estimate that MeHg contributes about 25% of total Hg in the water column of the Great Lakes. The predicted median concentrations of total Hg in top-carnivore fish were 0.13 mg/kg in Lake Superior and 0.16 mg/kg in Lake Erie. Predicted median MeHg concentrations in Lake Superior and Lake Erie (water column) were 0.019 and 0.075 ng/L, respectively. For both lakes, most (>55%) of the Hg was partitioned to sediments. Although the MCM simulation does have practical limitations (e.g., lakes are treated as fully-mixed open systems), the results demonstrate that generic assumptions of Hg behavior in all Great Lakes waterbodies are too simplistic.     

太湖、巢湖、龙感湖沉积物中磷的地球化学形态

A sequential extraction method for the fractionation of phosphorus （P） in lake sediments was used to analyze phos- phorus fractions of sediments taken from three large, shallow. eutrophic freshwater lakes of China-Talhu Lake. Chaohu Lake, and Long.an Lake. All three lakes are located in the lower reaches of the Changjiang River （Yangtze River）. In Taihu Lake and Chaohu Lake, algae blooms occurred every year, while Longgan Lake was a macrophyte-dominated lake. Results showed that exchangeable phosphorus fractions were much higher in the eutrophic lake sediments than in the macrophyte-flourishing lake sediment. Also, the ratio of Fe：P in the sediments of the algae-predomlnant lakes was generally much lower than that in the macrophyte-predominant lakes. Thus, the geochemical fractions of phosphorus in sediments had a closer relationship with the type of aquatic vegetation.     

湖北省保安湖水体营养状态监测与分析

[目的] 探究湖北省保安湖水体营养状态时空特征,分析影响湖泊水体叶绿素a的主要影响因子,为其生态修复与保护提供科学依据。[方法] 在湖区设置监测点位,于2019—2021年进行取样监测分析,并运用综合营养状态指数(TLI)评价湖区的营养状态。采用空间自相关分析对保安湖营养状态的空间相关性与聚集程度进行研究。通过Logit模型分析叶绿素a浓度变化的关键水环境影响因子。[结果] 保安湖TLI变化范围为47.25～55.86,营养状态在中营养和轻度富营养间波动。湖区营养状态整体呈现显著的正空间自相关关系,其Global Moran’s I分别为0.46,0.93,0.60,0.31,0.60和0.62。主体湖南部是TLI的热点(高/高集聚)区域(p<0.01),扁担塘湖区是TLI的冷点(低/低集聚)区域(p<0.01)。影响叶绿素a浓度变化的主要水环境因子排序为：透明度>TP>pH值>COD_Mn>水深>DO,均与叶绿素a浓度有显著相关性。[结论] 湖区水体营养状态良好。流域内应通过控制农田水土流失及养殖业面源污染,加强入湖河道治理等方式减少外源磷输入,采用生态水位调控和修复水生植被等措施来进一步改善水体营养状态。     

基于降水量的白洋淀最低水位预测研究

为了每年能够提前预测未来10月份至翌年4月份的白洋淀最低水位,指导水资源管理和防灾减灾,利用白洋淀区域多个气象站点雨季不同时段的平均降水量和白洋淀水位资料,采取历史资料回归和机器学习方法,对白洋淀水位随区域降水量的变化规律进行了分析,研究建立了一种利用当年雨季平均降水量和当年雨季前水位预测当年雨季后至翌年雨季前白洋淀最低水位的方法。通过建立最低水位预测模型对已有的数据进行验证,发现所建的模型模拟和预测的结果误差在5%以下,精度较高。根据2018年5月白洋淀水位和白洋淀区域2018年7-8月、7-9月平均降水量预测的2018年10月至2019年4月白洋淀的最低水位分别为8.52 m和8.38 m,根据最新监测的2018年10月至2019年2月20日的最低水位实况,预测误差在4%以下,预测精度较高。因此,所建模型能够提前3~7个月动态预测白洋淀即将出现的最低水位,可为提高雄安新区区域水资源综合管理水平、统筹分配区域水资源、合理安排补水等提供科学依据。