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1.
为了研究关中盆地浅层地下水氮污染对人体产生的潜在健康危害风险,在研究区采集和测试了232个水样,采用单因子污染指数法和健康风险评价模型对浅层地下水氮污染进行了评价。结果表明,在浅层地下水中硝态氮污染程度相对较重,呈面状分布;而铵态氮和亚硝态氮污染程度较轻,以点状存在。浅层地下水中硝态氮对人体健康的慢性毒害指数较高,高风险区占研究区面积的78.2%,主要分布在农业活动强烈的灌区和人口居住密集、工业相对发达的城镇区;硝态氮含量大于12.6mg/L的三类地下水对人体健康也是高风险的,即传统意义上可以饮用的三类水对人体健康并不都是安全的。上述成果对地下水资源管理和保护具有重要的参考价值。 相似文献
2.
由于人类活动影响,水体硝态氮污染已经成为世界范围内的环境问题。硝态氮污染不仅会造成水体富营养化,长期摄入过量硝酸盐还会严重威胁人体健康,控制并解决水体硝态氮污染是我国经济社会发展过程中亟待解决的重要环境问题。我国西南喀斯特地区是世界上面积最大、发育最典型和人地矛盾尖锐的岩溶连续分布带,具有十分脆弱且高度敏感的生态系统。与非喀斯特地区相比,这里水体硝态氮污染情况更为复杂和严重。因此,明确西南喀斯特地区内硝态氮的时空分布特征并对其来源进行解析是有效治理的前提。本研究梳理了近几十年来西南喀斯特地区水体硝态氮的现代监测结果,探讨了水体硝态氮时空分布特征、来源及受控机制等问题,发现:(1)区域内地表水硝态氮平均检出质量浓度不高,地下水检出质量浓度波动范围较大;(2)近几十年来,地表水硝态氮质量浓度整体呈现小幅增长趋势,而地下水检出质量浓度随时间的变化存在地域差异;(3)降水的稀释和冲携作用对区域内硝态氮质量浓度及分布的影响不容忽视,而人类活动导致的土地利用变化带来的影响可能成为未来的主控因素;(4)区域内水体硝态氮主要来源于铵态化肥、土壤有机氮、粪肥及污水,硝化作用是主要的转化过程。研究结果将为进一步认识喀斯特地区氮循环过程及促进地区可持续发展提供理论基础。 相似文献
3.
包气带作为防止地下水硝酸盐污染的天然屏障,其反硝化效果通常受到碳源的限制。针对地下水硝酸盐污染防治技术现状,本文采用Ca(OH)2处理的玉米芯作为反硝化的碳源材料,构建包气带强化反应层,用响应曲面法研究硝酸盐浓度、含水量和温度的交互作用对脱氮性能影响,并用硝态氮去除率、亚硝态氮累积、pH值变化以及溶解性有机碳(dissolved organic carbon, DOC)淋失通量综合评价脱氮性能,最后采用高通量测序揭示脱氮层中微生物变化。研究结果表明:温度、含水量以及温度和含水量交互作用对硝态氮去除率影响显著,其中温度是反硝化过程中最关键的因素;系统运行74天后,硝态氮去除率达到50%,亚硝态氮累积量(以N计)大多低于3 mg/L,pH值维持在7.0左右,DOC淋失通量(以C计)介于0.10.2 mg/(cm2·d);高通量测序发现,脱氮层中微生物的丰富度降低,而与反硝化和碳分解有关的微生物相对丰度提高,在碳源的刺激下微生物向有利于脱氮的方向演变。 相似文献
4.
对华北平原桓台县584个潜水水样的硝态氮含量进行了测定,应用地统计学方法对数据进行了分析,结果表明潜水硝态氮含量符合对数正态分布.采用Kriging方法对未观测点进行了估值,并绘制了等值线图,按照国家地下水质量标准划分的5个等级,利用GIS空间分析方法分别统计了各个乡镇潜水中硝态氮各等级的面积.同时把各乡镇单位面积化肥、人畜排泄、污水灌溉以及总的氮素年投入量与其潜水中硝态氮的平均含量分别进行了相关性分析,发现污水灌溉投入的氮素和各类氮素的总投入与潜水中硝态氮含量均有显著的相关关系,结果表明,污水灌溉对当地潜水硝态氮含量的影响很大,同时在对区域潜水硝态氮贡献的成因分析时必须考虑区域氮素的总投入. 相似文献
5.
6.
云南滇池流域西芹种植区不同施肥条件下的地下水环境氮素污染 总被引：1，自引：1，他引：0
通过野外田间实验,研究了高量施肥处理、低量施肥处理、不施肥处理以及空白对照裸地等不同施肥处理条件下土壤水中各种形态氮的时空分布情况,探讨了地下水环境中氮素在不同施肥处理条件下的迁移转化特征.结果表明,在各种处理条件下,土壤水中硝态氮质量浓度随深度的增大而减小,而亚硝态氮与铵态氮质量浓度在剖面上的变化幅度较大,这种变化主要受土壤水氧化还原电位的影响.硝态氮随时间的变化趋势在4个处理区表现各异:在高量施肥处理区,各层位的土壤水中硝态氮质量浓度总体上呈增大趋势;在低量施肥处理区,硝态氮受作物生长和灌溉的影响呈拍岸浪式向下迁移;在不施肥处理区和空白对照裸地处理区,由于表层土壤中硝态氮背景值较高(0～30 cm处土壤硝态氮平均质量分数达到15.59 g/kg),灌溉水的下渗也导致硝态氮向下迁移.高量施肥处理区和空白对照裸地处理区土壤水的对比表明,施肥可促进0.6～1.5 m深处土壤的反硝化作用,从而增大这些层位土壤水中亚硝态氮和铵态氮的质量浓度. 相似文献
7.
社会经济的发展和资源的利用产生了一系列环境问题，尤其是化肥的超量施用，已经危及包气带土体和地下水的质量安全。大量的氮素没有被农作物吸收，经微生物硝化作用后，以硝态氮的形式进入包气带土体，使包气带土体普遍受到氮素不同程度的污染。本文简述了包气带土体硝态氮污染的室内微生态修复、阻控技术和实验研究，探讨了今后应用的可行性。 相似文献
8.
灌水定额对玉米膜孔灌土壤水氮运移特性影响试验研究 总被引：1，自引：0，他引：1
通过玉米膜孔灌测坑试验,分析了灌水定额条件下的膜孔灌农田土壤垂直剖面水氮分布规律。经研究表明：灌水定额越大,土壤含水量越大,分布范围越广,土壤80~100 cm层的含水量越高;灌水定额越大,土壤表层（0~20.0 cm）含水量变化越大,硝态氮含量越小,变化越大,对深层80~100 cm硝态氮含量影响越大;随灌水定额的增加,硝态氮累积峰越靠下,低、中、高灌水定额的硝态氮累积峰分别出现在30 cm4、0 cm5、0 cm左右,高灌水定额时,增加了硝态氮的淋失,不利于作物对水氮的吸收。 相似文献
9.
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。 相似文献
10.
根据2010年5月至2010年10月每月对青木关地下河河水的监测数据,利用15N同位素技术并结合水化学指标,分析地下河的水化学特征以及硝态氮来源的时空变化特征。结果表明,地下河出口丁家龙洞硝态氮浓度(5.077mg/L)比入口天池硝态氮浓度(0.842mg/L)高6倍多。入口天池处地下河河水硝态氮浓度比较低,δ15N浓度变化范围为-7.0475‰~+7.059‰,变化幅度不大,说明该点的氮污染较低,地下水受外界影响较小,污水和粪便不是主要的δ15N来源。出口丁家龙洞处的δ15N浓度变化范围在-21.453‰~+37.825‰,总体浓度高且变化幅度大,受上游养猪场粪便直接排入及降水影响较大。 相似文献
11.
安徽淮北平原浅层地下水硝酸盐分布特征及污染来源分析 总被引：4，自引：0，他引：4
地下水中硝酸盐污染是当今世界许多国家或地区普遍关注的问题,研究其分布特征意义重大。文章在水文地质调查基础上,通过取样分析,研究了安徽省淮北平原浅层地下水硝酸盐分布状况和污染来源,结果表明:硝酸盐含量在东北地区较高,在一定范围超过饮用水限制标准(88mg/L),最高达432.56mg/L,研究区南部较低;NO3-与Cl-的同步增长关系表明其主要来源为生活污物和人畜排泄物,且该地区的农田肥料和污水灌溉很可能是另一主要来源;根据R型因子分析发现研究区内浅层地下水水质主要受到三方面的影响,即自然作用、自然与人为的混合作用和人为作用,且贡献率分别为39%、28%、15%。而人为作用中硝酸盐的相关度最高,因此建议加强研究区内人类活动中硝酸盐氮污染控制。 相似文献
12.
基于平均浓度法原理,根据黄河中游降雨径流特点,将年内过程分为汛期和非汛期两个阶段,同时将高含沙水流中的污染负荷分为水体中的溶解态污染负荷、泥沙吸附态负荷两部分,提出了多沙河流非点源污染负荷估算模型;根据黄河干流潼关断面1950-2006年实测水沙资料,结合水体、泥沙污染物浓度测定试验,分别计算了潼关断面2006年以及丰水年(P=25%)、平水年(P=50%)、枯水年(P=75%)3种不同代表年型下的非点源污染负荷.结果表明:黄河干流潼关断面年污染负荷以汛期为主,汛期污染负荷以非点源为主;非点源污染负荷中,硝酸盐氮、氨氮以溶解态为主,总磷以吸附态为主;潼关断面非点源污染负荷占全年负荷比例:丰水年时,硝酸盐氮占63.09%,氨氮占61.32%,总氮占87.17%、总磷占89.83%;枯水年时,硝酸盐氮占26.92%,氨氮占24.62%,总氮占67.60%、总磷占71.73%.2006年,硝酸盐氮、氨氮、总氮和总磷非点源污染负荷占全年比例依次为:17%、14%、15%和41%. 相似文献
13.
本文应用污染指数法,对北方某经济开发区及周边地下水水质进行了污染评价,结果表明研究区地下水水质以轻污染和中污染为主,局部地区出现较重污染,主要指标为硝酸盐氮、三氯甲烷和三氯乙烯。通过对工业废水、再生水、河水水质的检测,发现研究区地表水水质与污水处理厂再生水排放密切相关,地下水污染很可能与开发区企业排污有关。由于开发区所处位置的环境敏感性和脆弱性,建议今后在开发区及附近继续开展相关研究,进一步查明地下水的硝酸盐氮及有机污染物来源、污染途径,建立完善的监测体系,以便及时切断污染源,保障城市及当地供水安全。 相似文献
14.
Manouchehr Chitsazan M. Mohammad Rezapour Tabari Mehdi Eilbeigi 《Environmental Earth Sciences》2017,76(11):391
Considering the importance of groundwater resources in water-supply demands in arid and semiarid areas such as Iran, it is essential to investigate the risk of groundwater pollution. Nitrate is one of the main pollutants that penetrate into the groundwater from various sources such as chemical fertilizers, pesticides, and domestic and industrial sewage. Unfortunately currently, nitrate contamination of the aquifers is a serious problem in Iran. The Karaj aquifer is not exempted, and the nitrate pollution zone, with concentrations far beyond the permitted limit (50 mg/L), expands fast. In this paper, the long-term groundwater-quality data (from 2000 to 2013) collected from Alborz Province Water and Wastewater Company were analyzed using ArcGIS10 and statistical software, and the spatial and temporal patterns of nitrate pollution in drinking-water wells in the Karaj plain and effective parameters (such as depth to groundwater level, hydraulic gradient, land use, precipitation, and urban, agricultural and industrial wastewater) were investigated. The authors also investigated the status of nitrate concentration variation using the concepts of geostatistics, based on determinations from 62 to 194 surveyed wells with a suitable distribution across the plain. With respect to the relationship between quality parameters, hydrogeological status of the aquifer and land usage, causes of the increase in the concentration of nitrate in the water and its trend were investigated as well. Results revealed that the nitrate levels in the northern portion of the study area were the highest with maximum concentrations of 181.7 mg/L from 2000 to 2013. Based on nitrate concentration distribution maps, the levels of nitrate increased from 2006 onwards to 26–100 mg/L. Unfortunately from 2008 to 2012, a pollution zone with a nitrate water concentration of 101–150 mg/L has been observed and even a concentration of 180 mg/L has been determined. In 2000, the entire aquifer area has been drinkable but with the increase in nitrate concentration, the area with undrinkable water has expanded to 21% in 2003, 24% in 2005, 33% in 2007, 39% in 2009, 43% in 2011 and 44% in 2013. The results of this study could provide valuable information with on the status of nitrate water concentrations in the Karaj plain which demands proper strategies and qualitative approaches in the future. 相似文献
15.
Modeling the risk of nitrate leaching and nitrate runoff loss from intensive farmland in the Baiyangdian Basin of the North China Plain 总被引：2，自引：0，他引：2
The water movement and soil nitrogen cycle of the Baiyangdian Basin were simulated, and the risk of nitrate leaching and nitrate runoff loss from intensive farmland was assessed by using the distributed hydrological soil and water assessment tool (SWAT) in this study. The model assessment showed that SWAT was able to simulate water and nitrate movement in the region with satisfactory results. The modeling analysis indicated that fertilizer application was the overriding source of soil nitrogen and might result in a large amount of nitrate accumulation in soils; this nitrate might be lost by leaching or runoff driven by water movement. In 2009, nitrate nitrogen leaching represented 19.5 % of the total amount of nitrogen fertilizer application, while nitrate nitrogen runoff represented 1.7 % only. Thus, it showed that the nitrate leaching was the main approach of soil nitrogen movement in farmland because of strong percolation. It also showed a significant variation of nitrate leaching from different soil depths, with the largest amount leached from surface soil layers and the smallest amount leached from lower soil layers. Therefore, it could be further revealed that the nitrate concentration was very low at soil layers lower than the root zone of crops (1.2 m). Validated by groundwater observations, groundwater pollution by nitrate derived from fertilizers was not serious because of the deep groundwater level in the study plain. However, the risk of groundwater pollution would increase significantly if precipitation increased. 相似文献
16.
Nitrate pollution of groundwater in the Yellow River delta,China 总被引：8，自引：0，他引：8
Jianyao Chen Makoto Taniguchi Guanqun Liu Kunihide Miyaoka Shin-ichi Onodera Tomochika Tokunaga Yoshihiro Fukushima 《Hydrogeology Journal》2007,15(8):1605-1614
Nitrate pollution of groundwater in the Yellow River delta, China is an important issue related not only to nitrate dispersion and health concerns but also to mass transport and interactions of groundwater, sea, and river waters in the coastal area. The spatial distribution of nitrate, nitrate sources, and nitrogen transformation processes were investigated by field surveys and geochemical methods. Nitrate occurred mainly in shallow layers and had a spatial distribution coinciding with geomorphology and land/water use. Irrigation water from the Yellow River and anthropogenic waste are two main nitrogen sources of nitrate in the delta, and both denitrification and mixing processes could take place according to characteristics identified by ionic and isotopic data. 相似文献
17.
氮氧同位素在河流硝酸盐研究中的应用 总被引：9，自引：0，他引：9
多年来，世界各地河流普遍存在硝酸盐污染问题。为控制河流的硝酸盐污染，确定河水中硝酸盐的来源以及研究氮的循环过程就显得尤为重要。由于在不同成因下，硝酸盐的δ15N和δ18O存在着较大差异，因此利用氮、氧同位素方法研究河流硝酸盐问题正日益受到国内外研究人员的重视。综述了用硝酸盐中氮、氧同位素来研究河流硝酸盐的不同来源(大气沉降、化肥、牲畜粪、土壤硝酸盐等)和示踪其地球化学循环过程，特别是反硝化过程，这两方面的研究进展，并对我国河流硝酸盐研究现状进行了讨论及提出今后的研究方向。 相似文献
18.
Alexander Zaporozec 《Environmental Geology》1983,5(1):35-38
In recent years, considerable interest has been expressed in the nitrate content of water supplies. The most notable toxic
effect of nitrate is infant methemoglobinemia. The risk of this disease increases significantly at nitrate-nitrogen levels
exceeding 10 mg/l. For this reason, this concentration has been established as a limit for drinking water in many countries.
In natural waters, nitrate is a minor ionic constituent and seldom accounts for more than a few percent of the total anions.
However, nitrate in a significant concentration may occur in the vicinity of some point sources such as septic tanks, manure
pits, and waste-disposal sites. Non-point sources contributing to groundwater pollution are numerous and a majority of them
are related to agricultural activities.
The largest single anthropogenic input of nitrate into the groundwater is fertilizer. Even though it has not been proven that
nitrogen fertilizers are responsible for much of nitrate pollution, they are generally recognized as the main threat to groundwater
quality, especially when inefficiently applied to irrigated fields on sandy soils. The biggest challenge facing today's agriculture
is to maintain the balance between the enhancement of crop productivity and the risk of groundwater pollution.
Presented at the International Symposium, International Association of Hydrogeologists, “Impact of Agricultural Activities
on Ground Water Quality and Quantity,” Prague, Czechoslovakia, September, 1982. 相似文献