大沙河水库主要入库河流氮磷营养输入分析

为了解大沙河水库流域内营养盐输入对水库水质的影响,以 2011年3月~2012年2月大沙河水库5条主要入库河流(大沙河、白沙河、双石河、富食河和沃江河)的水文水质监测数据为依据,分析了这些入库河流的流量和氮磷营养盐浓度,并估算了外源负荷总量,旨在为水库进行高效和合理的流域规划以及水质保护方案的制定提供科学依据。结果表明:位于西南方向的白沙河年平均流量最大(1.01 m³·s^-1),西北部富食河流量最小(0.23 m³·s^-1)。各入库河流总氮平均浓度变化范围为1.62~4.37 mg·L^-1,总磷平均浓度范围为0.08~0.36 mg·L^-1,其中富食河氮和磷营养盐的浓度最高,大沙河总氮浓度最低,白沙河总磷浓度最低,总体上西北部河流的氮磷浓度高于西南部河流。全年大沙河水库总氮输入量为176.7 t,总磷输入量为13.7 t。在所有入库河流中,位于水库北部的沃江河对水库营养盐输入量贡献最大,氮、磷负荷分别占总输入量的33%和32%,位于西部的双石河氮负荷最小(12%),西南方向大沙河磷负荷最小(9%)。     

三峡水库蓄水前后香溪河氮磷污染状况研究

分别于三峡水库蓄水前的上世纪1996—1997年及蓄水后的2004年采集了香溪河水样及沉积物样,研究了蓄水前后香溪河氮磷的污染状况。结果表明,蓄水前上游总磷浓度低于0.05mg/L,下游在0.22—0.34mg/L之间,其浓度与生活污水及工业废水排放有关;总氮浓度变化不大,在0.7—1.1mg/L之间。蓄水后磷、氮浓度明显升高,但总磷在回水区由于沉降作用反而低于蓄水前。蓄水后下游氮磷比普遍高于10,加之水流变缓,使香溪河库湾发生“水华”的可能性增加。香溪河沉积物磷污染严重,总磷含量高达1221mg/kg,主要以无机磷污染为主。三峡水库蓄水后,对上游库湾水环境的不利影响已开始显现出来,必须采取有效措施,防止水环境的恶化。     

绿色屋顶径流氮磷浓度分布及赋存形态

为了解绿色屋顶暴雨径流的氮磷浓度分布及赋存形态,在重庆大学构建了两种绿色屋顶,于2009年9月至2011年10月期间进行了绿色屋顶和对照屋面的暴雨径流水质监测。研究结果表明,绿色屋顶暴雨径流pH值在7.7左右,氨氮浓度满足地表水环境质量标准Ⅲ类标准;总氮、总磷、硝酸根的平均浓度分别为3.6—4.4 mg/L、0.17—0.28 mg/L和3.1—3.7 mg/L,均高于降雨雨水浓度;与对照屋面暴雨径流相比,同时期的绿色屋顶暴雨径流中总氮、氨氮和总磷浓度较低,而硝酸根、磷酸根浓度较高。绿色屋顶暴雨径流水质的季节差异明显,夏季污染物浓度较低,而春秋季节污染物浓度较高;总体上看,随绿色屋顶运行时间的延长,暴雨径流中总氮和硝酸根浓度逐渐降低,而总磷和磷酸盐浓度则呈现出一定的波动性。气象因素、降雨雨水水质与绿色屋顶暴雨径流水质的相关性分析表明,气温越高、前期干旱时间越长,越有利于绿色屋顶径流中氨氮浓度的降低;绿色屋顶径流中的总磷和氨氮主要来自降雨。研究结果为绿色屋顶的科学构建和城市暴雨径流管理提供了重要参考。     

广西刁江流域主要河流水质评价

为研究广西刁江水质污染现状, 从刁江流域上游到下游共设置 9 个水质监测断面。于 2013 年 12 月-2014 年 12月对河流的 pH、溶解氧、高锰酸盐指数、叶绿素 a、总氮、总磷、氨氮、硝酸盐氮、亚硝酸盐氮、正磷酸盐、重金属(砷、铅、镉、汞、铬)水质指标进行监测。采用单因子和综合污染指数对刁江水质进行评价, 同时开展水体富营养化评价。单因子污染指数评价结果表明刁江流域主要污染物为总氮和砷。综合污染指数评价结果表明刁江流域水质整体较好, 但上游的平村河污染较严重。从时间分布来看, 秋季水质最差, 冬季较好。从营养化状态指数来看, 平村河为中度富营养化状态, 其余河流为中营养状态, 富营养化程度呈现春夏高, 冬季低的特点。对评价结果进行主成分分析, 结果表明刁江流域总氮最大的贡献者可能来源于居民的生活污水。     

漳泽水库主要入库河流氮、磷营养盐特征

以2006—2007年的漳泽水库3条入库河流(南漳河、石子河、绛河)的水文、水质调查数据为依据,研究了漳泽水库入库河流的主要水文变化特征、氮磷营养盐浓度及其通量的逐月动态。3条入库河流水体流速缓慢,水温适宜,年平均值在12.5℃～15.1℃。3—5月水温回升较快,夏季水温高,光照充足,易发生水华。3条入库河流中总氮含量年平均值在1.75～8.90mg·mL-1,总磷含量平均值在0.005～3.760mg·mL-1,氮磷营养盐浓度总体偏高,其中石子河贡献了48.3%的总氮和77.3%的总磷。溶解态无机氮(DIN)是氮的主要存在形式,而其中又以硝酸盐氮(NO3--N)为主,平均占到DIN的60%以上。氮磷通量季节性变化规律不明显,且月均波动较为平缓。点源污染是氮磷进入南漳河、石子河的主要途径,而绛河的氮主要来自面源污染。从保护漳泽水库的角度考虑,应重点控制南漳河和石子河的点源污染。     

氮磷汇入驱动下的河流轮虫群落演替

【目的】解析污染条件下河流生物区系的演替过程及机制,可以为生物多样性减少提供诊断,为生物多样性保护和水生生态系统的生态安全提供科学支撑。【方法】以对污染具有指示作用的轮虫类群为研究对象,选择覆盖京津冀地区的、受到人类活动干扰的北三河水系为研究区域,分别对该区域富营养化相关水质参数和轮虫群落组成进行分析,在解析污染物排放导致的河流水体水质差异和轮虫群落组成差异的基础上,阐明导致轮虫群落演替的关键污染因子。【结果】水体水质指标的分析结果表明,西部河流与东部诸河具有明显不同的环境条件,其氮、磷指标(包括总氮、溶解性总氮、总磷、溶解性总磷及活性磷)浓度显著增加。轮虫群落的分析结果表明,与东部诸河相比,西部河流的物种数目、生物个体数、物种丰度及香农威纳指数均显著降低,且群落组成显著差异。群落-环境相关分析显示,总氮、溶解性总氮、总磷、溶解性总磷、活性磷以及氨氮是导致群落显著差异的关键环境因子。【结论】北三河水系西部河流的氮、磷含量显著高于东北部河流;在环境条件改变的前提下,北三河水系西部河流比东部河流物种丰度、生物量均显著减少,同时群落组成也显著改变,高耐污型物种出现。氮、磷元素的输入是导致轮虫群落演替的关键环境因子。     

太平湖水库水质的理化特征

总结了1985年11月至1986年7月太平湖水库水质的理化特性,结果表明:太平湖水库水质良好,透明度高平均为321cm;pH值平均为7.4;水中溶解氧丰富;总离子量较低;水质属重碳酸盐类钙组Ⅰ型水(CⅠCa).水中主要生物营养元素氮含量较高,总氮平均为1.49mg/L,磷含量较低,总磷平均为0.012mg/L.氮、磷比为124.2:1,表明磷是该水体生物生产力的限制性营养元素。水中多数理化组分有明显的季节变化,多数理化组分在平面和垂直分布上也有差异,但差异不显着。       

贵州草海氮磷分布特征及沉积物释放通量估算

通过对草海丰水期和枯水期水体、表层沉积物及周边河流水体系统的样品采集与测试分析,阐明丰水期和枯水期氮磷在草海水体的空间分布特征,分析表层沉积物中氮磷的释放通量的空间分布特征,识别沉积物的"源"和"汇"特征。结果表明,两个水文期大部分入湖河流的总氮和总磷浓度高于出湖河流,湖水氮磷浓度受外源输入影响较明显;丰、枯两期挺水植物区水中氮磷浓度高于沉水植物区,且沿主要水流方向逐渐降低;丰水期水-沉积物界面水中氮磷浓度高于表层水体,枯水期该特征不明显。枯水期沉积物中总氮的释放通量范围为5.244~362.506 mg·m~(-2)·d~(-1),呈现出"源"的特征;沉积物中总磷释放通量范围为-3.081~3.009 mg·m~(-2)·d~(-1),在挺水植物区表现为"汇",在沉水植物区表现为"源",内源释放也不可忽视。     

水生植物腐烂分解对水质的影响

对6种水生植物进行64 d的腐烂分解试验,对比不同水生植物腐烂分解过程中水体营养盐浓度的变化.结果表明： 6种水生植物的腐烂分解速率差别较大,浮叶植物分解速度最快,沉水植物次之,挺水植物最慢.不同水生植物腐解过程对水质影响不同,并与植物生物量密度相关.挺水植物芦苇腐解过程中的水体化学需氧量、总氮和总磷浓度最低;在茭草分解后期,水体化学需氧量和总氮浓度上升,水质变差.浮叶植物荇菜和莲腐解过程中,水体化学需氧量和总氮浓度高于其他植物.沉水植物菹草和狐尾藻腐解过程中,水体铵态氮、硝态氮和总磷浓度最高.对于同一种植物,不同生物量密度处理下,主要水质指标变化趋势相似.适量的植物残体的存在可以有效促进水体氮、磷等营养元素的循环,一定程度上去除硝态氮,降低水体氮负荷.     

洱海流域44种湿地植物的氮磷含量特征

研究湿地植物中的氮和磷含量既能帮助了解其所处生境的营养状况,又能为湿地生态恢复提供指导。测定了洱海流域44种湿地植物干生物量中的氮、磷含量。结果表明洱海湿地植物中总氮和总磷平均含量为15.7 mg/g和3.3 mg/g,变化范围为6.4-34.3 mg/g和1.4-6.5 mg/g,明显高于其他地区;氮磷比范围为2.2-9.5,显示该地区磷过剩,氮是限制因子;不同功能群植物间的氮和磷含量有显著差异,总氮含量以沉水植物最高而挺水和漂浮/浮叶植物最低,而总磷含量则为湿生植物最高而沉水植物最低;植物的地上部分分别占有整株72%的生物量、82%的氮含量和75%的磷含量,表明收割湿地植物的地上部分可以高效去除湿地生态系统中的氮和磷。     

不同时空尺度下土地利用对洱海入湖河流水质的影响

土地利用与入湖河流水质的关系存在时空差异。以洱海西部入湖河流及其小流域为研究对象,综合空间分析和数理统计手段,探讨两者随空间尺度和时间变化的关系,结果表明:选取的小流域、河岸带30m缓冲区、河岸带60m缓冲区和河岸带90m缓冲区4种尺度下,对入湖河流水质影响显著的土地利用类型为建设用地和植被(包括林地和牧草地),影响最大的空间尺度为小流域尺度,河岸带30m缓冲区次之;小流域尺度下,建设用地面积百分比与入湖河流COD和TP浓度呈正相关,植被面积百分比与NH_4~+-N浓度呈负相关,响应土地利用的主要水质指标为TN和TP,回归调整系数分别为0.624和0.579;季节性关联分析表明建设用地与COD、NH_4~+-N、TP的回归关系在雨季强于旱季,植被与COD、TP的回归关系在雨季强于旱季,雨季建设用地和植被面积变化引起COD浓度变化更快。在流域管理中,针对植被覆盖率低、建设用地占比高的白鹤溪和中和溪应重点加强雨季土地利用管控,增加植被覆盖率,合理开发建设用地。     

基于氮磷比解析太湖苕溪水体营养现状及应对策略

生态化学计量学是评价水体营养状态的重要手段,利用其氮磷比指标探讨了我国太湖主要入湖河流苕溪的营养状态。野外监测结果显示,苕溪水体氮素超标严重,磷素污染轻度,硝酸盐、颗粒态磷为氮磷的主要赋存形态,且氮磷浓度呈现相似的季节变化规律,表明苕溪主要受农业面源污染影响。氮磷比分析表明,苕溪水体春、秋季处于磷素限制状态,夏季适合藻类生长,冬季低温条件下不利于藻类的大量繁殖;苕溪生物量增长受磷素限制,线性拟合亦显示其氮磷比主要受磷素波动的调控;苕溪干流大面积暴发蓝藻水华的风险较部分支流及死水区低,苕溪水入湖后,特别是夏季其暴发风险将显著提高。针对苕溪水体的富营养化现状,提出若干条水质改善应对策略。     

赣江流域土地利用方式对河流水质的影响

赣江是鄱阳湖的最大支流,是鄱阳湖水污染物的主要来源,查明流域土地利用方式对赣江水质的影响和鄱阳湖的水环境保护具有重要意义。基于2012年对赣江7个主要支流NH+4-N、TP、CODMn和DO浓度的每月测定结果,通过不同空间尺度和土地类型等级划分,利用相关分析和冗余分析研究土地利用方式对赣江流域河流水质的影响。研究结果表明,子流域的土地利用方式对TP的影响大于缓冲区;对CODMn的影响在丰水期大于缓冲区,在枯水期小于缓冲区;对NH+4-N的影响在丰水期与缓冲区接近,在枯水期小于缓冲区;DO受土地利用方式的影响较小。水田中的丘陵水田是赣江水体TP和丰水期CODMn的主要来源;平原水田是枯水期CODMn的主要来源。居民建设用地中的城镇用地是赣江水体TP、NH+4-N和丰水期CODMn的主要来源,农村用地是CODMn的主要来源。水域中的水库坑塘是赣江水体TP和丰水期NH+4-N、CODMn的主要来源。     

Effects of Land Use,Topography and Socio-Economic Factors on River Water Quality in a Mountainous Watershed with Intensive Agricultural Production in East China

Understanding the primary effects of anthropogenic activities and natural factors on river water quality is important in the study and efficient management of water resources. In this study, analysis of Variance (ANOVA), Principal component analysis (PCA), Pearson correlations, Multiple regression analysis (MRA) and Redundancy analysis (RDA) were applied as an integrated approach in a GIS environment to explore the temporal and spatial variations in river water quality and to estimate the influence of watershed land use, topography and socio-economic factors on river water quality based on 3 years of water quality monitoring data for the Cao-E River system. The statistical analysis revealed that TN, pH and temperature were generally higher in the rainy season, whereas BOD₅, DO and turbidity were higher in the dry season. Spatial variations in river water quality were related to numerous anthropogenic and natural factors. Urban land use was found to be the most important explanatory variable for BOD₅, COD_Mn, TN, DN, NH₄ ⁺-N, NO₃ ⁻-N, DO, pH and TP. The animal husbandry output per capita was an important predictor of TP and turbidity, and the gross domestic product per capita largely determined spatial variations in EC. The remaining unexplained variance was related to other factors, such as topography. Our results suggested that pollution control of animal waste discharge in rural settlements, agricultural runoff in cropland, industrial production pollution and domestic pollution in urban and industrial areas were important within the Cao-E River basin. Moreover, the percentage of the total overall river water quality variance explained by an individual variable and/or all environmental variables (according to RDA) can assist in quantitatively identifying the primary factors that control pollution at the watershed scale.     

Estimation of long-term variation in nutrient loads from the Hii River by comparing the change in observed and calculated loads in the catchments

To study the long-term change in nutrient loads from the Hii River to Lake Shinji, water samples were taken repeatedly over a year in 1983/1984 and again in 2001/2002. Annual total nitrogen (TN) loads, estimated from observations of water quality and river flow, increased from 860 to 920 t with a corresponding increase in NO₃–N concentration during the cool season. In contrast, total phosphorus (TP) loads decreased from 96 to 62 t. Annual TN and TP loads, calculated using emission factors and annual statistics for the catchments, showed a tendency to decline from 1986 to 2002. No source could be identified which would result in the increase in TN in the catchments, therefore, the increase in observed TN loads was considered to originate in other areas. Atmospheric nitrogen deposition transported from long distances has elevated the sum of NH₄–N and NO₃–N concentration in rainwater in the cool season. Therefore, it was considered that this resulted in the increase in TN loads in the Hii River.     

Using a nitrogen and oxygen isotopic approach to identify nitrate sources and cycling in the Wei River of northwestern China

The Wei River is the largest tributary of the Yellow River in China. To understand the sources and cycling of nitrate in the Wei River, we determined the concentrations and nitrogen and oxygen isotopic values of nitrate from water samples. Our results revealed that NO₃^?-N dominated the inorganic N and ranged from 0.1 to 8.8 mg/L (averaging 3.3 mg/L). Although this NO₃^?-N concentration does not exceed the World Health Organization's drinking water standard of 10 mg/L, the NO₃^?-N content of most water samples exceeded 3 mg/L, indicating poor water quality. The NO₃^?-N concentrations and δ¹⁵N-NO₃^? values demonstrate that there are significant differences in the spatial distribution of nitrogen between the tributaries and the main stream of the Wei River. In addition, a negative linear relationship (r² = 0.63) between NO₃^?-N concentrations and δ¹⁸O-NO₃^? values suggests mixing between two distinct sources (fertilizer and manure or sewage). Furthermore, we infer that the main source of nitrate is not manure or sewage itself, but rather the nitrification of NH₄⁺ in manure and sewage. Finally, no obvious denitrification processes were observed. These results expand our understanding of sewage as a major source of nitrate to the Wei River, emphasizing the role of nitrification.     

Nitrogen and Phosphorus Pollutants Removal from Rice Field Drainage with Ecological Agriculture Ditch: A Field Case

Excessive nitrogen and phosphorus in agricultural drainage can cause a series of water environmental problems such as eutrophication of water bodies and non-point source pollution. By monitoring the water purification effect of a paddy ditch wetland in Gaochun, Nanjing, Jiangsu Province, we investigated the spatial and temporal distribution patterns of N and P pollutants in paddy drains during the whole reproductive period of rice. Then, the dynamic changes of nitrogen and phosphorus in time and space during the two processes of rainfall after basal fertilization and topdressing were analyzed after comparison. At last, the effect of the ditch wetland on nutrient purification and treatment mechanism, along with changing flow and concentration in paddy drains, was clarified. The results of this study showed that the concentrations of various nitrogen and phosphorus in the ditch basically reached the peak on the second and third days after the rainfall (5.98 mg/L for TN and 0.21 mg/L for TP), which provided a response time for effective control of nitrogen and phosphorus loss. The drainage can be purified by the ecological ditch, about 89.61%, 89.03%, 89.61%, 98.14%, and 79.05% of TN, NH₄⁺-N, NO₃⁻-N, NO₂⁻-N, and TP decline. It is more effective than natural ditches for water purification with 80.59%, 40%, 12.07%, 91.06% and 18.42% removal rates, respectively. The results of the study can provide a theoretical basis for controlling agricultural non-point source pollution and improving the water environment of rivers and lakes scientifically.     

The 1994 experimental opening of the Bonnet Carre Spillway to divert Mississippi River water into Lake Pontchartrain, Louisiana

A diversion of Mississippi River water into Lake Pontchartrain, Louisiana, USA by way of the Bonnet Carre Spillway has been proposed as a restoration technique to help offset regional wetland loss. An experimental diversion of Mississippi River water into Lake Pontchartrain was carried out in April 1994 to monitor the fate of nutrients and sediments in the spillway and Lake Pontchartrain. Approximately 6.4×10⁸ m³ of Mississippi River water was diverted into Lake Pontchartrain over 42 days. As water passed through the Bonnet Carre Spillway, there were reductions in total suspended sediment concentrations of 82–83%, nitrite+nitrate (NO_x) of 28–42%, in total nitrogen (TN) of 26–30%, and in total phosphorus (TP) of 50–59%. 3.9±1.1 cm of accretion was measured in the spillway. Nutrient concentrations at the freshwater plume edge in Lake Pontchartrain compared to the Mississippi River were lower for NO_x (44–81%), TN (37–57%), and TP (40–70%), and generally higher for organic nitrogen (−7–57%). The Si:N ratio generally increased and the N:P ratio decreased from the river to the plume edge. Nutrient stoichiometric ratios indicate water at the plume edge was not silicate limited, suggesting conditions favoring diatomic phytoplankton.     

Study on ecological protection and rehabilitation technology of a reservoir-type water source in the northeastern region of China

ABSTRACT

Surface water is the main source of water for human life and production. The quality of water affects living conditions and the overall health of people. Ecological protection and restoration engineering technology, combining ecological revetment and an ecological floating bed, is applied to a selected shallow beach experimentation area of a reservoir water source area in Northeast China. According to local conditions, the ecological revetment plants were identified as Goosegrass, sedges, and water grasses, and other local species of Polygonum hydropiper bagen, reeds, and bulrushes were identified as ecological floating bed plants. Regular monitoring of water quality in the experimentation area and a control area showed that the ecological protection and restoration technology can effectively reduce the concentrations of BOD₅ (five day biochemical oxygen demand), COD (chemical oxygen demand), TN, NH₃-N, NO₃^?-N, TP, TDP, Mn, Zn, Fe, Pb, total coliforms, and other indicators of surface water in the experimentation area. The BOD₅, COD, Max TN, NH₃-N, NO₃^?-N, TP, and TDP reduction rates were 84.76%, 57.14%, 86.76%, 83.78%, 89.26%, 94.02%, and 95.89%, respectively, with the implementation of water pollution prevention and the purifying shoal.     

滇池流域退耕区植物群落构建对地表径流污染物的削减效应

为探索不同群落的构建在滇池流域的实际应用,以确定削减污染物最优植物群落的配置方式,该研究选取地表径流悬浮物(SS)、COD含量、总氮(TN)、总磷(TP)、氨氮(NH_4~+-N)、硝氮(NO_3~--N)六个指标作为主要的分析对象,在滇池流域退耕区开展了不同植物群落配置对地表径流污染物削减效应的试验研究。结果表明:三个植物群落对SS、COD、TN、TP、NO_3~--N在2014年和2015年间均表现出显著性的削减趋势,且三个植物群落对SS、TP和NO_3~--N的削减率均在45%以上,但并未对NH_4~+-N表现出削减效果。不同植物群落对污染物的削减效应存在一定的差异性,但是三个不同群落与年度的交互作用对SS、COD、TN、TP、NO_3~--N五个养分指标的削减并没有表现出显著的差异性。从整体上来看,三种植物群落类型中,以乔-灌-草构建的立体式植物群落对地表径流污染物的削减效果最佳。