渭河干流典型断面非点源污染监测与负荷估算

渭河水质在较大程度上受非点源污染的影响,因此,有必要对其负荷和比重进行研究。2009年至2010年,对渭河干流关中段咸阳和临潼断面进行了洪水期和非洪水期水质水量同步监测。根据监测结果及水文站实测流量资料,分别采用改进的水文分割法和平均浓度法对两断面的非点源污染负荷进行了计算,分析了非点源污染的特点。结果表明:渭河干流关中段主要污染物为COD、NH₃-N和TN,两断面洪水期间各指标的平均浓度基本都小于平时的平均浓度;各指标非洪水期浓度变化总体上小于洪水期浓度变化幅度,量级较大的洪水水质变化幅度相对较小;改进的水文分割法和已被检验并被广泛采用的平均浓度法计算结果符合良好。2009年(枯水年,P=68%)渭河咸阳和临潼站各指标非点源污染所占比例基本在20%～30%左右;2009年渭河干流咸阳-临潼河段污染以点源污染为主,构成比例在80%以上。对比2006年(枯水年,P=69%),2009年临潼站COD、NH₃-N和TN年点源负荷分别减少11937t、791t和29t,渭河点源治理取得一定成效;此外,临潼站这两年的污染构成比例基本相同。非点源污染在渭河水污染中占较大比重,其对渭河水质的影响不容忽视。     

辽河大伙房水库汇水区农业非点源污染入库模拟

利用输出系数法和SWAT模型,对大伙房水库汇水区农业非点源污染(ANSP)进行了入库模拟研究,并用2006—2009年的水文和水质监测数据对模型进行了校准和验证。研究结果表明:汇水区年均输入到水库的泥沙量、总氮和总磷负荷分别为82.65×103 t、1 873.49t和81.97t;月入库泥沙量、总氮和总磷负荷与径流量有着较强的相关性,ANSP的产生和迁移受降水、径流过程影响很大,每年7、8月份的氮、磷和泥沙流失量达到年内最大值,分别占全年流失总量的42.64%、44.42%和67.91%。水库汇水区各流域对水库氮、磷污染的贡献率由大到小依次为:浑河流域(清原段)、苏子河流域、社河流域和水库周边小流域。     

颗粒态氮磷负荷模型研究

为研究妫水河流域的颗粒态氮磷非点源污染来源,以控制非点源污染,在官厅水库周围进行了野外人工降雨试验。试验数据表明,氮磷输移率与产沙率具有很好的相关性,颗粒态氮、磷的平均相关系数分别为0.9594和0.9772。建立了新的颗粒态氮磷负荷模型,其中富集系数等于泥沙中总氮总磷百分含量与土壤中百分含量之比。根据妫水河流域的土壤图、土地利用图及数字高程模型,应用新的模型研究了妫水河流域颗粒态氮磷污染负荷的空间分布。结果表明,颗粒态氮磷主要来自地表植被覆盖差的丘陵和山地。     

丹江鹦鹉沟小流域氮素随径流的迁移及对水质的影响

计算小流域非点源氮素流失负荷,并以此开展丹江水源区水体污染源解析和控制研究。基于流域断面及小区监测试验,利用平均浓度法对鹦鹉沟流域氮素年均流失模数和不同土地利用类型的非点源污染负荷进行计算分析。结果表明:径流水质中主要是总氮质量浓度超标,且硝氮质量浓度均大于氨氮质量浓度;当坡耕地坡度大于25°时,氮素流失严重,水质极差;农村生产生活污染物排放对水质有很大影响,从断面1到把口站,硝氮质量浓度和总氮质量浓度增加较大;农地、草地和林地的总氮年均径流流失模数分别为0.36、0.22和0.09t/(a·km2);流域出口非点源污染物氨氮、硝氮和总氮的平均质量浓度分别为0.17,4.71和7.55mg/L,点源污染物氨氮、硝氮和总氮的平均质量浓度分别为0.20、2.12和4.08mg/L。总体来说,鹦鹉沟流域径流中总氮的流失模数为0.89t/(a·km2),总氮是影响水质的主要污染物,需加强对坡耕地氮素流失和农村生活垃圾的治理。     

太湖流域雪堰镇氮素流失规律及形态特性

以太湖流域雪堰镇为例,通过2009年3月~2010年2月连续12个月及两场次降雨事件的水质监测进行分析,研究不同河流、月份、区域、汛情、土地利用类型下氮素流失规律及形态特性,分析降雨过程中不同尺度3个流域(上涧村、龙泉河、雪堰镇)氮流失特征和不同河段氮流失规律。研究结果表明,雪堰镇氮素为劣Ⅴ类,非汛期污染比汛期严重,变化幅度大,不稳定,氮以溶解态为主,溶解态氮以硝氮为主;镇区硝氮浓度较非镇区低,氨氮比非镇区高,坑塘水面氮流失最严重,有林地(乔木较多)氮流失最少,茶园硝氮占溶解态氮百分比最高,果园氨氮占溶解态氮百分比最高;降雨前期未产流前氮素流失稳定,产流后流失越来越大,不同河段氮沿程变化基本稳定。     

长江三峡库区干流水体主要污染负荷来源及贡献

目前三峡水库枯水期已有11.1%的监测断面水质超标。城区江段岸边水质已出现较为严重的污染带。利用面向环境问题的污染负荷计量方法,对长江三峡库区干流水体主要污染负荷来源及贡献进行了分析。结果表明,富营养化污染负荷2003年总量为2.79万t PO₄3-当量,其中总磷贡献量最大,占总量的45.8%。其次是总氮和COD_Cr,分别占37.9%和16.4%。城市生活污水和农业施肥是主要来源,分别占总量的61.0%和26.3%。水生生态毒性污染负荷为7 612.6t 1,4-二氯苯当量。其中挥发酚和汞贡献量分别占78.0%和21.2%。来自城市生活污水占76.52%,重点工业企业的占23.48%。富营养化污染负荷有逐年增加趋势。重点工业企业六价铬和铅,城市污水中挥发酚水生生态毒性污染负荷增加较快。     

张掖黑河湿地国家级自然保护区水质现状分析研究

2020年全年,在张掖黑河湿地国家级自然保护区选取13个监测点进行采样,分析总磷(TP)、氨氮(NH3-3)、总氮(TN)、溶解氧(DO)、五日生化需氧量(BOD5)、化学需氧量(COD)、高锰酸盐指数(Imn)等重要指标,得出张掖湿地水质现状。研究显示,张掖黑河湿地自然保护区非汛期较汛期污染程度重;污染断面重点在甘州区山丹桥和三闸二社,高台湿地公园断面次之;张掖湿地水质主要是氮磷和有机物污染,因子按超标严重程度分别为:总氮、氨氮、总磷。     

基于污染负荷核算的岷江流域总磷污染成因分析及对策

总磷是长江流域水环境污染的首要超标因子,岷江作为长江上游流量最大的支流,总磷污染严重,对长江总磷污染贡献较大。为了解岷江流域总磷污染,采用排污系数法,计算得到2016年岷江流域污染源总磷入河量为1 154 t,以农村生活污染负荷占比最高(51.3%),其次为城镇生活源(28.7%)、农业非点源(8.24%)、工业源(9.57%)、畜禽养殖源(1.21%),城市径流源(0.99%)最低;在空间上岷江流域总磷污染负荷呈中游(64.2%)>下游(32.6%)>上游(3.1%)的特点,与岷江干流总磷浓度变化趋势相符,其中成都市总磷污染负荷最高(51.2%),与区域人口密度高、生产和生活活动密集有关。结合资料收集和现场调查,岷江流域总磷污染成因主要包括农村生活污染治理缺口较大、城镇生活污染处理基础设施建设不足、工业企业密布、部分支流总磷污染严重、水污染治理导向不全面。针对岷江总磷污染负荷分布特征及成因,提出“上游保护优质水体、中游治理重污染水体、下游恢复不达标水体”的分区污染防治对策,统筹流域监管体制机制,强化岷江流域水环境保护和治理。     

基于资源理论的黄河干流水资源评价

采用循化、小川、兰州、下河沿、青铜峡、石嘴山、三湖河口、头道拐、吴堡、龙门、潼关、三门峡、花园口、泺口和利津共15个黄河干流沿线水文监测断面,计算各水文监测断面水资源多年平均组成。各水文断面监测项目包括水位、流量、气温、水温、pH、电导率、钙、镁、钾、氯离子、硫酸根离子、碳酸根离子、碳酸氢根离子、离子总量、溶解氧、氨氮、亚硝酸盐氮、硝酸盐氮、高锰酸盐指数、生化需氧量、氰化物、砷化物、挥发酚、六价铬、汞、镉、铅、铜、铁、锌和细菌总数等。基于资源理论,采用指标对黄河干流水量和水质进行了统一度量。根据黄河干流实测数据,对水资源化学、物理和生物进行核算,并分析多年水资源变化趋势以模拟黄河干流水资源空间分布状况。最后,势高概念的提出为进一步量化和比较黄河干流的生态发展状况提供基础。     

基于资源(火用)理论的黄河干流水资源评价

采用循化、小川、兰州、下河沿、青铜峡、石嘴山、三湖河口、头道拐、吴堡、龙门、潼关、三门峡、花园口、泺口和利津共15个黄河干流沿线水文监测断面,计算各水文监测断面水资源多年平均组成。各水文断面监测项目包括水位、流量、气温、水温、pH、电导率、钙、镁、钾、氯离子、硫酸根离子、碳酸根离子、碳酸氢根离子、离子总量、溶解氧、氨氮、亚硝酸盐氮、硝酸盐氮、高锰酸盐指数、生化需氧量、氰化物、砷化物、挥发酚、六价铬、汞、镉、铅、铜、铁、锌和细菌总数等。基于资源[火用]理论,采用[火用]指标对黄河干流水量和水质进行了统一度量。根据黄河干流实测数据,对水资源化学[火用]、物理[火用]和生物[火用]进行核算,并分析多年水资源[火用]变化趋势以模拟黄河干流水资源空间分布状况。最后,[火用]势高概念的提出为进一步量化和比较黄河干流的生态发展状况提供基础。     

三峡库区低等级土质道路侵蚀研究

以三峡库区界垭小流域内不同交通荷载土质道路为研究对象,通过自然降雨观测研究其侵蚀规律和污染物流失特征。研究结果表明,交通荷载大的干道产流率和侵蚀率均高于交通荷载低的支道,对产流率影响显著的因子主要为降雨量,对产沙率影响显著的因子为降雨量、雨强。雨型对污染物的流失特征影响显著,前期集中型降雨下,污染物流失过程线与降雨过程线同步性较好,泥沙、总氮、铵态氮、泥沙结合态磷和溶解态磷均发生了较强的初始冲刷效应;中期集中型降雨下,污染物流失浓度峰值优先于雨强峰值,且氮和磷等初始冲刷强度低于前期集中型降雨,泥沙无初始冲刷效应。     

Simulation of spatial and temporal distribution on dissolved non-point source nitrogen and phosphorus load in Jialing River Watershed,China

Jialing River, which covers a basin area of 160,000 km² and a length of 1,280 km, is the largest tributary of the catchment area in Three Gorges Reservoir Area, China. In recent years, water quality in the reservoir area section of Jialing River has been degraded due to land use and the rural residential area induced by non-point source pollution. Therefore, the semi-distributed land-use runoff process (SLURP) hydrological model has been introduced and used to simulate the integrated hydrological cycle of the Jialing River Watershed (JRW). A coupling watershed model between the SLURP hydrological model and dissolved non-point source pollution model has been proposed in an attempt to evaluate the potential dissolved non-point source pollution load; it enhances the simulation precision of runoff and pollution load which are both based on the same division of land use types in the watershed. The proposed model has been applied in JRW to simulate the temporal and spatial distribution of the dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP) pollution load for the period 1990–2007. It is shown that both the temporal and spatial distribution of DTN and DTP load are positively correlated to annual rainfall height. Land use is the key factor controlling the distribution of DTN and DTP load. The source compositions of DTN and DTP are different, where average DTN pollution load in descending order is land use 67.2%, livestock and poultry breeding 30.5%, and rural settlements 2.2%; and for DTP, livestock and poultry breeding is 50%, land use 48.8%, and rural settlements 1.2%. The contribution rates of DTN and DTP load in each sub-basin indicate the sensitivity of the results to the temporal and spatial distribution of different pollution sources. These data were of great significance for the prediction and estimation of the future changing trends of dissolved non-point source pollution load carried by rainfall runoff in the JRW and for studies of their transport and influence in the Three Gorges Reservoir.     

Modeling impacts of sediment delivery ratio and land management on adsorbed non-point source nitrogen and phosphorus load in a mountainous basin of the Three Gorges reservoir area, China

Agricultural nonpoint source (NPS) pollution at the Three Gorges reservoir area in China has been increasingly recognized as a threat to aquatic environment in recent years due to the serious eutrophication problem. Adsorbed NPS pollution is one of the major forms of NPS pollution in mountainous regions, the essential of the adsorbed NPS pollution is soil loss. Thus, simple, highly sensitive and continuous methods are required to simulate and quantify sediments yield at watershed scales. It is imperative to construct an integrated model to estimate the sediment yield and adsorbed NPS pollution load. According to the characteristics of climate, hydrology, topography, geology, geomorphology and land use types in Three Gorges reservoir area, a GIS-based dynamic-integrated-distributed model of annual adsorbed NPS load was presented in view of impacts of the rainfall intensity, sediment delivery ratio (SDR) and land management, where the temporally dynamic-continuous model of annual sediment yield was established by modifying the revised Universal Soil Loss Equation (RUSLE), and the spatially integrated-distributed model of annual adsorbed NPS load was then developed via the correlation between sediment yield and adsorbed NPS load. Furthermore, a case study of the Jialing River basin in China was applied to validate the integrated model, the dynamic-distributed coupling among GIS technology, sediment yield model, and adsorbed NPS load model was achieved successfully. The simulation results demonstrate the following: (1) runoff and sediment are influenced greatly by rainfall intensity, SDR and vegetation cover; rainfall and land management show high sensitivities to the integrated model; the average annual adsorbed TN and TP pollution loads from 2006 to 2010 decreased by 76 and 74 % compared with the previous treatment (1990), respectively. (2) Spatio-temporal variations of adsorbed NPS nitrogen and phosphorus load are mainly related to different land use types and the background level of nutriments in topsoil; different land use types have different contribution rates; the largest contribution rates of adsorbed total nitrogen (TN, 58.9 %) and total phosphorus (TP, 53 %) loads are both from the dryland cropland. (3) The identification of critical source areas can help to implement the prevention and control measures aiming at the reduction of water environmental pollution. These results will provide useful and valuable information for decision makers and planners to take sustainable land use management and soil conservation measures for the control of sediment pollution in the Three Gorges reservoir area. The application of this model in the catchment shows that the integrated model may be used as a major tool to assess sediment yield risks and adsorbed NPS pollution load at mountainous watersheds.     

江淮丘陵区典型农业小流域磷素输出时程变化特征

以安徽省滁州市花山流域为例,开展水量与地表径流磷素浓度同步监测,研究了江淮丘陵区典型农业小流域总磷浓度和输出负荷的时程变化特征和不同连续天数最大输出负荷占全年负荷的比例特征。研究结果表明:花山流域总磷浓度年内变化对于降雨径流过程存在响应关系,年内总磷浓度汛期普遍高于非汛期;流域总磷输出负荷在年中呈现脉冲式输出特点,且输出主要集中在夏季汛期的雨洪时段,在不到全年10%的时段内,花山流域的总磷输出负荷占到全年输出负荷的50%以上。     

Geospatial modeling for assessing the nutrient load of a Himalayan lake

This research makes use of the remote sensing, simulation modeling and field observations to assess the non-point source pollution load of a Himalayan lake from its catchment. The lake catchment, spread over an area of about 11 km², is covered by different land cover types including wasteland (36%), rocky outcrops (30%), agriculture (12%), plantation (12.2%), horticulture (6.2%) and built-up (3.1%) The GIS-based distributed modeling approach employed relied on the use of geospatial data sets for simulating runoff, sediment, and nutrient (N and P) loadings from a watershed, given variable-size source areas, on a continuous basis using daily time steps for weather data and water balance calculations. The model simulations showed that the highest amount of nutrient loadings are observed during wet season in the month of March (905.65 kg of dissolved N, 10 kg of dissolved P, 10,386.81 kg of total N and 2,381.89 kg of total P). During the wet season, the runoff being the highest, almost all the excess soil nutrients that are trapped in the soil are easily flushed out and thus contribute to higher nutrient loading into the lake during this time period. The 11-year simulations (1994–2004) showed that the main source areas of nutrient pollution are agriculture lands and wastelands. On an average basis, the source areas generated about 3,969.66 kg/year of total nitrogen and 817.25 kg/year of total phosphorous. Nash–Sutcliffe coefficients of correlation between the daily observed and predicted nutrient load ranged in value from 0.80 to 0.91 for both nitrogen and phosphorus.     

农业非点源污染模型AnnAGNPS适用性检验

以大沽河典型小流域为研究区,借助GIS和相关资料提取参数,建立模型数据库。在此基础上,采用2001～2002年小流域出口径流量、泥沙和总氮监测数据优化参数、校准和验证模型,分析AnnAGNPS模型在大沽河典型小流域的适用性。结果表明,模型对日均径流量、泥沙及总氮输出的模拟能力较差,而对年均污染负荷估算结果比较理想。当前AnnAGNPS模型主要被用于评价流域非点源污染的长期影响及最佳管理措施的选择精度足矣。     

Estimating non-point source pollutant loads for the large-scale basin of the Yangtze River in China

Taking advantage of the opportunity provided by the nationally funded Water Resources Integrated Planning and Investigation of China program (WRIPI), a model was established to estimate non-point source pollutant loads in a large-scale basin (ENPS-LSB) on the basis of hydrological processes and pollutant transport. The model made use of Environment for Visualizing Images software (ENVI) and Interactive Data Language (IDL) and took the characteristics of present-day China into account: a huge rural population scattered widely, marginal rural infrastructure and livestock cultivation based on scatter-feeding. The model was divided into two sections: one on dissolved and one on adsorbed pollutant loads. The dissolved loads were divided into four different types: those originating from agricultural fields, urban areas, rural residential areas, and livestock. The study was undertaken in the Yangtze River Basin. The results showed the chemical oxygen demand (COD), the total nitrogen (TN), the total phosphorous (TP), and the ammonia nitrogen (NH₃–N) loads to be 2.6 × 10⁶, 1.6 × 10⁶, 9.3 × 10⁵ and 3.1 × 10⁵ tons, respectively, in the year 2000. The dissolved COD resulted mainly from rural residential areas and livestock; 76.8% of the dissolved TN and 86.4% of the dissolved TP produced were from agricultural fields. The Yangtze River Delta, the lower reaches of the Han River, and part of the Dongting Lake, Taihu Lake and Poyang Lake basins all had relatively high dissolved pollutant loads; adsorbed nitrogen and phosphorus loads were mainly observed in the middle and upper reaches of the Yangtze River Basin. Dissolved loads were most affected by human activity, whereas adsorbed loads were most affected by natural factors. The results showed that the model performed well on large scale, describing pollutant loads effectively. This makes it possible to properly consider not only point source pollutant discharge but also non-point source pollution in the Yangtze River Basin. Combining point source discharge investigation with the ENPS-LSB model could assist environmental management with controlling water pollution.     

Evaluation of the extent of pollution of discharged oil field brine in the Bonny estuary,Niger Delta,Nigeria

This is an assessment of the degree of effects of discharged produced water in river and sediments of the Bonny estuary, Niger Delta. It involved seasonal analyses of twenty-two (22) water and thirty-four (34) sediment samples from the Bonny River. The physicochemical properties (i.e., hydrocarbon content, heavy metals, and other inorganic constituents) of the water samples were examined, while the sediments were inspected for heavy metals and organic hydrocarbon constituents that may have been sourced from the discharged produced water. In addition, the principal component and cluster analyses, index of geoaccumulation, and pollution load index plots were utilized to deduce the degree of pollution, source, and distribution of these contaminants. From the results of the analyses, the Bonny seawater is contaminated with nitrate, phosphates, nickel, ammonia, and phenols in dry season, whereas nitrate, sulfate, phosphate, total nitrogen, total petroleum hydrocarbon (TPH), and heavy metals—zinc and lead—are observed in the rainy (wet) season. Similarly, the sediments are contaminated with benzene, toluene, ethyl benzene, xylene, polycyclic aromatic hydrocarbon, TPH, phenols, and heavy metals in both seasons. Considering the outcomes of these analyses, it is evident that the composition and quality of seawater and sediments of the Bonny estuary have been strongly influenced by produced water discharges in the area.