水污染源特性查定程序

本文对水污染湖源特性查定的程序以及查定中遇到的技术问题和解决办法进行了论述，为污染源查定工作科学化，规范化进行了有益探索。     

上海市松江镇饮用水水源区的保护与环境管理方案

保护集镇饮用水河流是当前水污染防治工作的重点。本文通过现状分析，针对城乡结合部河流以面源为主的特点，找出影响饮用水河流水质的主要污染源及污水排放特征．用系统分析方法，将集镇的经济、人口、环境统计资料作为环境管理模型的主要输入信息，经计算机仿真，得出保护水源水质应采取的对策与治理方案。     

天津地区表层土中饱和烃的组成与分布特征

为揭示天津地区不同环境功能区表层土壤中饱和烃污染特征及其来源,分析了该地区几个具代表性的环境功能区表层土(0～25cm)中饱和烃化合物的组成和分布特征,重点讨论了正构烷烃和甾、萜烷烃类化合物的组成、分布及环境意义,比较了不同层次(亚层)(0～5cm,5～10cm,10～15cm,15～20cm,20～25cm)中这些化合物及相关的地球化学参数的变化规律。结果表明,不同采样点以及同一采样点的不同亚层之间正构烷烃的组成特征存在不同程度的差别,而甾、萜烷烃类化合物组成与分布特征均较为接近。正构烷烃以及甾、萜类地球化学参数综合分析揭示,不同采样点之间正构烷烃的来源多样,中低分子量的正构烷烃主要来源于石油等化石燃料,高分子量正构烷烃主要来源于高等植物蜡的分解产物,但甾、萜烷烃类化合物的来源是一致的,且主要来源于石油烃污染。不同采样点表层土中饱和烃的来源及污染程度均存在一定的差别,市区、油田附近、经济开发区以及近郊区受石油源影响较重,北部山区污染较轻,且主要来源于高等植物的降解。除个别采样点外,同一采样点不同亚层之间饱和烃的组成特征基本一致,表明污染源是一致的,主要来源由表层污染物往下迁移所致。     

环太湖丘陵地区农田氮素随地表径流输出特征

对环太湖丘陵地区农田氮素随地表径流的输出特征进行了研究,结果表明,地表径流中TN浓度随径流量而变化,浓度峰值出现时间滞后于径流量峰值;径流发生前期,NH3 N和NO-3 N浓度水平相当,后期NO-3 N浓度缓慢抬升,而NH3 N含量缓慢下降;NO-2 N浓度相对较低,随时间快速下降;对于TN和NO-3 N而言,溶解态含量高于悬浮态,而溶解态和悬浮态NH3 N的浓度相当;无机氮平均浓度高于有机氮,有机氮尤其是悬浮态有机氮浓度表现出随径流量而变化的特点。     

Assessment of groundwater contamination using geographic information systems

In this study two sites were selected in order to investigate groundwater contamination and spatial relationships among groundwater quality, topography, geology, landuse and pollution sources. One site is the Asan area, an agricultural district where pollution sources are scattered and which is mainly underlain by granite of Cretaceous age. The other site is the Gurogu area of Seoul city, an industrial district where an industrial complex and residential areas are located and which is mainly underlain by gneiss of Precambrian age. Groundwater samples collected from these districts were analysed for chemical constituents. An attribute value files of chemical constituents of groundwater and the spatial data layers were constructed and pollution properties were investigated to establish out spatial relationships between the groundwater constituents and pollution sources using geographic information systems (GIS).Relatively high contents of Si and HCO₃ ^– in the groundwater from the Asan area reflect the effect of water–rock interaction whereas high contents of Cl^–, NO₃ ^– and Ca²⁺ in the groundwater from the Gurogu area are due to the pollution of various sources. The significant seasonal variation of SiO₂, HCO₂ ^– and Ca²⁺ contents, and that of Ca²⁺ content were observed in the Asan and the Gurogu areas, respectively. Seasonal variation of pollutants such as Cl^–, NO₃ ^– and SO₄ ^2– was not observed in either area. Pollution over the critical level of the Korean drinking water standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. Pollution by NO₃ ^–, Cl^–, Fe²⁺, Mn²⁺, SO₄ ^2– and Zn²⁺ in the groundwater from the industrial district (Gurogu area) and that of NO₃ , SO₄ ^2– and Zn²⁺ in the groundwater from the agricultural district (Asan area) were observed. The principal pollutant in both areas is NO₃ ^–. Deep groundwater from the Asan area is not yet contaminated with NO₃ ^– except for one site, but most of the shallow groundwater site occurring near the potential point sources is seriously contaminated. From the result of buffering analysis, it seems clear that factories and stock farms are the principal pollution sources in the Asan area. The groundwater from the Gurogu area has already been seriously polluted considering the fact of NO₃ ^– contamination of deep groundwater. Chlorine pollution of shallow groundwater in the Gurogu area was also observed. Spatial relationship between pollution level and its source was clarified in this study by using GIS, which will be applicable to the effective management of groundwater quality.     

巢湖流域不同土地利用类型地表径流污染特征研究

巢湖是我国五大淡水湖之一,目前正面临着严重的环境污染与水体富营养化问题。通过对巢湖流域塘西地区大豆地,水稻田,菜地,山芋地,小麦地,集镇街道,山坡地,饲养场地,农村道路,湖滩芦苇地,荒地等１１种土地利用类型地表径流污染现状的详细调查与分析,建立了巢湖流域不同土地利用类型地表径流污染研究的一般程序与方法。     

EFFECTS OF BEST MANAGEMENT PRACTICES ON FOREST STREAMWATER QUALITY IN EASTERN KENTUCKY1

ABSTRACT: Forest land managers are concerned about the effects of logging on soil erosion, streamflow, and water quality and are promoting the use of Best Management Practices (BMPs) to control impacts. To compare the effects of BMP implementation on streamwater quality, two of three small watersheds in Kentucky were harvested in 1983 and 1984, one with BMPs, the other without BMPs. There was no effect of clearcutting on stream temperatures. Streamflow increased by 17.8 cm (123 percent) on the BMP watershed during the first 17 months after cutting and by 20.6 cm (138 percent) on the Non-BMP watershed. Water yields remained significantly elevated compared to the uncut watershed 8 years after harvesting. Suspended sediment flux was 14 and 30 times higher on the BMP and Non-BMP Watersheds, respectively, than on the uncut watershed during treatment, and 4 and 6.5 times higher in the 17 months after treatment was complete. Clearcutting resulted in increased concentrations of nitrate, and other nutrients compared to the uncut watershed, and concentrations were highest on the non-BMP watershed. Recovery of biotic control over nutrient losses occurred within three years of clearcutting. The streamside buffer strip was effective in reducing the impact of clearcutting on water yield and sediment flux.     

RELATIONSHIPS BETWEEN LAND USES AND RAINWATER QUALITY IN A SOUTHCENTRAL PENNSYLVANIA WATERSHED1

ABSTRACT: Spatial and temporal variability in rainfall concentrations of nutrients, major ions, and herbicides was monitored at 7 locations in or near the Conodoguinet Creek watershed in south-central Pennsylvania from 1991.1993. Results were used to (1) compare precipitation quality in forested, agricultural and urban areas, and (2) assess the practicality of using volunteer citizen monitoring in such a study. As indicated in previous studies, sulfate and nitrogen concentrations in precipitation were linked to sample pH. Concentrations of major ions in precipitation appeared to relate more to regional influences rather than local influences. However, concentrations of herbicides in precipitation may have been influenced by both regional and local use which caused compounds like atrazine, deethylatrazine, propazine, simazine, metolachior, alachlor, ametryn, and prometon to be present in detectable concentrations in rainfall. Seasonality was evident in nitrogen, sulfate, pH, and herbicide data and was suggested in calcium, iron, manganese, magnesium, orthophosphate, and chloride data. Agricultural weed control activities were probably responsible for the seasonal pattern in pesticide data which peaked in May and June. Tropical storm Danielle may have caused the apparent seasonal patterns for the other nine parameters. This storm did not follow the typical west to east movement pattern and consequently produced rainfall of relative high quality. A variety of quality assurance checks indicated that trained volunteer citizen monitors were successful participants in this intensive and extensive scientific study, collecting good quality samples in a timely manner. Without this kind of volunteer help, it is extremely difficult to complete studies that require sampling in response to natural events such as rainfall.     

ANALYSIS OF NITROGEN MANAGEMENT STRATEGIES USING EPIC1

ABSTRACT: This paper illustrates a method of using a hydrologic/water quality model to analyze alternative management practices and recommend best management practices (BMPs) to reduce nitrate-nitrogen (NO₃^--N) leaching losses. The study area for this research is Tipton, an agriculturally intensive area in southwest Oklahoma. We used Erosion Productivity Impact Calculator (EPIC), a field-scale hydrologic/water quality model, to analyze alternative agricultural management practices. The model was first validated using observed data from a cotton demonstration experiment conducted in the Tipton area. Following that, EPIC was used to simulate fertilizer response curves for cotton and wheat crops under irrigated and dryland conditions. From the fertilizer response functions (N-uptake and N-leaching), we established an optimum fertilizer application rate for each crop. Individual crop performances were then simulated at optimum fertilizer application rates and crop rotations for the Tipton area, which were selected based on three criteria: (a) minimum amount of NO₃^--N leached, (b) minimum concentration of NO₃^--N leached, and (c) maximum utilization of NO₃^--M. Further we illustrate that by considering residual N from alfalfa as a credit to the following crop and crediting NO₃^--N present in the irrigation water, it is possible to reduce further NO₃^--N loss without affecting crop yield.     

COMPARING SAMPLING SCHEMES FOR MONITORING POLLUTANT EXPORT FROM A DAIRY PASTURE1

ABSTRACT: Dairy cow pastures and feeding areas around barns can be a significant source of nonpoint source pollutants to nearby streams. To help document the significance of these sources, nutrient export in streamfiow from a 56.7-ha, mostly agricultural, watershed located in southwestern North Carolina was monitored from August 1994 to January 1996. Total nitrogen and phosphorus export rates from the upper, predominantly pasture, part of the watershed were 18.0 and 1.4 kg/ha/yr, respectively, as measured by weekly grab sampling and 18.7 and 4.9 kg/halyr, respectively, as measured from storm event monitoring. Nitrogen and phosphorus export rates for the area between the monitoring sites, which included overgrazed cow holding and feeding areas and farm buildings, were 376 and 86 kgfhalyr, respectively, for grab sampling and 351 and 160 kg/ha/yr, respectively, for storm event monitoring. To estimate the amount of reduction from nonpoint source controls necessary to effect a significant reduction in pollutant loading, statistical analyses of the load data were conducted. The analyses for the five pollutants monitored showed that total suspended solids would require the greatest reduction (34.6 percent for weekly grab and 33.6 percent for storm) in loading after the implementation of controls for statistical significance. Nitrate plus nitrite was found to require the least reduction (12.6 percent for weekly grab). Pollutant export rates computed from weekly grab samples and storm event samples used separately were compared to corresponding export rates computed from combining grab and storm event samples to assess the differences in monitoring schemes.