Nitrogen export by runoff from agricultural plots in two basins in China

Runoff and sediment yields from agricultural fields are major sources of nitrogen (N) entering lakes in China. Export of sediment and N can be impacted by soil and cropping management practices, but there is relatively little information on N leaving agricultural fields in lake basins in China. Sediment and surface runoff N from a series of field plots in two experimental lake basins were evaluated in situ under simulated rainfall conditions. Objectives of the study were to evaluate the effects of crop cover, slope, and fertilizer application on N in surface runoff and eroded soils. Sediment yields varied from 4.3 to 299.0 g m^-2, depending on management practice. Mean dissolved nitrogen (DN) and total nitrogen (TN) concentrations are 1.35 and 5.4 mg L^-1, respectively, in Lake Taihu basin, while mean DN and TN concentrations are 2.66 and 4.3 mg L^-1, respectively, in Lake Baiyangdian basin. For all experimental plots in two basins, weighted average concentrations of N for total-N, dissolved N and sediment N are 1.0-5.0 mg L^-1, much higher than 0.2 mg L^-1, indicating a problem in lake eutrophication due to high N concentration from agricultural surface runoff. The estimated mean annual export of total N was 6.0 and 14.7 kg ha^-1 yr^-1 for Baiyangdian and Taihu lake basins, respectively. The study showed that significantly more N (approximately ranging from 10 to 90 of total N) exported was associated with sediment, constituting a long-term source of potentially bioavailable N in lakes.     

我国盐湖锂资源分离提取进展

锂及其化合物是国民经济和国防建设的重要战略资源，在储能电池、精细化工、原子能热核聚变等领域有着重要应用。中国是锂资源消耗与生产大国，但我国锂消费量对外依存度达70%以上，同时我国锂资源主要储存在西部地区的盐湖卤水中，低锂浓度、高镁锂比的问题提升了盐湖提锂的难度。针对我国盐湖提锂现存的问题，本文系统总结了盐湖锂资源分离提取常见的传统方法，并重点阐述了新型膜分离材料及新型膜分离过程在盐湖卤水高效提锂方面的重要进展，特别是我国科研工作者在盐湖提锂应用中所取得的最新成果。     

微污染水源水中氨氮的危害与现代处理技术

在我国微污染水源水中,氨氮污染问题尤为突出,而目前自来水厂大多采用传统工艺,主要针对悬浮物、细菌和病毒,对氨氮的去除效果差,所以必须进行工艺改造。针对我国的微污染水源水中氨氮的污染现状,对当下去除微污染水源水中氨氮的常见物化法、生物法和联合处理法进行综述,介绍了它们的原理和优缺点,并对未来微污染水源中氨氮的去除技术进行了展望。     

寒冷地区湖库富营养化模型研究进展

近年来,随着我国北方寒冷地区水污染问题的加剧,该地区湖库富营养化的发生频率和程度也逐年增加.由于气候及水环境条件的特殊性,寒冷地区湖库中的营养盐浓度水平及分布在丰水期、平水期以及冰封期存在着不同的规律,而模型是研究和提出湖库富营养化治理方案的主要手段.为此,在总结归纳寒冷地区湖库水质特征的基础上,对近年来国内外湖库富营养化模型的研究现状与进展进行了综述,并对寒冷地区湖库富营养化模型未来的研究方向进行了展望.     

城市湖泊的臭氧降解研究

研究臭氧降解方法去除城市湖泊湖水中有机污染的可行性。以广州市五个湖泊湖水为原水样．分别用重铬酸钾法和微生物法BOD快速测定仪测定臭氧降解前后湖泊水的COD和BOD值,并探讨了降解时间的影响。结果表明．臭氧降解方法可以去除城市湖泊中部分有机物质,广州市五个湖泊中麓湖COD去除率最高达49．4％,其它湖泊COD去除率30．0％～35．0％．而且臭氧降解方法还可以提高湖水中有机物的可生化性。     

Levels and Origin of PAHs in Some Big Lakes

This study was designed to assess the contamination of a very special lake, Lake Baikal in Siberia, and two big lakes, Ladoga and Onega in the European part of Russia, by polycyclic aromatic hydrocarbons (PAHs). PAH compounds were analyzed by HPLC and the target PAH, benzo[ a ]pyrene (B a P), by using the spectral-luminescence (Shpol'skii) method. Elevated levels (to 96 w g kg m 1 ) of B a P in sediments of Lake Baikal reflected proximity to potential sources of emission, situated either on shore (a paper and pulp mill in Baikalsk) or upstream river systems. The concentration of B a P in sediments decreased with the distance from outlet and the depth. The sediment samples contained several representatives of PAHs. The total content of identified compounds reached 873 w g kg m 1 (less than four nuclear representatives not included). Dominating heavy PAHs were dibenz[ a,j ]anthracene, dibenz[ a,h ]anthracene, dibenzo[ a,e ]pyrene, and dibenzo[ a,l ]pyrene. The concentration of B a P in sediments of northeastern Baikal was more than two times less than that for the southern part of the lake and corresponds to the background level. The B a P levels estimated for sediments close to paper and pulp mills of the Lake Ladoga exceeded 160 w g kg m 1 , being two orders of magnitude higher than that for other areas of these lakes. The contamination of sediments of Lake Onega by PAHs is affected by pulp and paper mills as well as other sources. Our results clearly demonstrate the contribution of specific industrial sources like paper and pulp mills to the content of PAHs in the Baikal, Ladoga, and Onega water ecosystem.     

磷 ,洗涤剂和富营养化的控制——欧洲和北美经验(英文)

富营养化引起一系列严重问题。早期在北部温暖岩地区的研究认为磷是导致富营养化的决定元素 ,控制磷含量是治理富营养化的最佳途径。废水中的磷大约有 2 5 %来自于洗涤剂所含的磷酸盐 ,因此一直存在要求改进洗涤剂配方的压力。然而要使环境产生显著改善光靠减少这部分磷的含量是远远不够的。目前 ,控制富营养化的手段仍主要依靠控制废水中的磷含量 ,但人们清楚 ,不同地区影响因素是各不相同的。在低洼地区 ,水中的磷主要来源于农业活动。而在另一些土壤肥沃的地区 ,氮化物相对于磷更缺乏 ,这是因为在湖盆边缘潮湿地区的脱氮作用 ,大量硝酸盐可能从土壤中淋溶出去 ,在这种环境下只能通过控制氮来加以改善。其他地区如浅湖 ,温带热带地区的湖泊 ,在富营养化问题上也都是氮比磷重要。在某些地区强调控制磷含量是正确的 ,但并不适用于所有地区。片面强调污水处理同样也不是包治百病的灵丹妙药。只改变洗涤剂的配方并不能显著地改善环境。这些观点反映了我们对富营养化问题虽己有所了解但还需要更加全面、系统地去看待     

Nitrogen budget and surface water nitrogen load in Changshu: a case study in the Taihu Lake region of China

The Taihu Lake region in China is highly developed, but surface water pollution has become a serious environmental problem in recent years, with nitrogen (N) a major pollutant. To assess the impact of human activity on N cycle and to evaluate the sources of N in surface water in the region, a N-budget for Changshu, a representative county in the Taihu Lake region, was established by using N-related human activities data from an intensive household survey conducted in 2007, measurement data on N fluxes and literature data on other necessary parameters. Chemical fertilizer was the largest N input, accounting for 56.3%. Nearly 30% of the N ended up in surface water. Untreated human and animal waste was the major source of N transported to water. The huge amount of N load to surface water would result in N concentrations of >6.0 mg N L⁻¹ even after denitrification removal in wetlands.     

On-farm assessment of soil erosion and non-point source pollution in a rain-fed vegetable production system at Dianchi lake’s catchment, southwestern China

Vegetable is important cash crop in Dianchi lake’s catchment, but the non-point source (NPS) pollution from the intensive agricultural production systems is a critical hurdle on the alleviation of serious eutrophication in Dianchi lake. Our objectives were to quantify soil erosion and NPS pollution in rain-fed vegetable production systems at the area. The experiment was a randomized complete factorial design with two plastic mulch treatments (narrow vs. wide plastic mulch) and two rotation treatments (broccoli–zucchini–winter wheat vs. broccoli–zucchini–fallow). The narrow-plastic-mulch system has significantly (P < 0.05) increased runoff and soil loss than wide-plastic-mulch system. Results indicated that plastic mulch substantially accelerated runoff generation and soil erosion at vegetable seedling stages, whereas runoff and soil loss were apparently alleviated in furrow with residue mulch. The sediment transport played a predominant role in soil nitrogen (N) and phosphorus (P) movement by surface runoff. The annual losses of N and P via surface runoff in the vegetable field were ranged from 2.0 to 5.1 kg/ha and 0.3 to 1.1 kg/ha respectively in the three considerably drier rain season, but their losses never exceeded 1 % of the annual fertilizer application. Removal of crop residues was the major causes of N and P export from the soil in the vegetable fields, which exceeded 20 and 8 % of the annual nitrogen and phosphorus fertilizer application respectively. This implicated that inappropriately discarding of the residues would pose serious consequences for water contamination of Dianchi lake. As under appropriate discarding of residues, the wide-plastic-mulch system could improve NPS pollution control and crop production in vegetable field at Dianchi lake’s catchment.     

沂沭河底泥中污染物空间分布特征及评价

测定沂沭河底泥的有机质(OM)、总氮(TN)、总磷(TP)及有效磷含量,分析了污染物之间的相关性,评价了沂沭河底泥的污染状况.结果表明:沂沭河流域表层沉积物中TN、TP分布特性相似,沂河中OM含量远低于沭河,OM、TN、TP分布的空间差异较大.有效磷含量约占TP含量的17.7％,表明农田及人类活动对流域水环境造成了一定...     

以土壤沟槽渗滤系统为主体的组合工艺技术在污染河道治理中的应用效果

生物过滤和土壤沟槽渗滤系统组合工艺处理污染河水结合底泥原位稳定化技术处理河道底泥,处理效果好、成本低、无二次污染,可应用于内陆河流、城市河段、湖泊、生活污水等范围的水体修复。经在宁波市邹家河河道进行污染水体去污试验,结果表明各项水质指标较处理前均有了较大的改善,对COD、BOD5的去除率为80％以上,对氨氮的去除率一般为65％以上,对总磷的去除率为75％以上。该组合工艺的河道修复处理成本为0．018元/t水,大大降低了运行成本。     

富锂盐湖提锂工艺研究进展

通过对富锂盐湖物质来源的分析,论述了全球富锂盐湖的成因以及主要分布区域,列出了全球主要富锂盐湖的锂资源量及分布情况。按照富锂盐湖水化学组分的不同将富锂盐湖划分为碳酸盐型、硫酸盐型和氯化物型三大类,并根据盐湖水Mg/Li比值的大小分为高镁锂比和低镁锂比卤水。按照上述对富锂盐湖的分类,对不同类型的富锂盐湖锂资源的开发工艺进行了详细的综述。提出盐湖提锂工业化进程需解决以下几个问题：开发能耗低、工艺简单、成本低、污染小的工艺路线;注重矿产的综合开发利用、提高矿产开发的附加值;将提锂工艺的开发和环境保护结合起来。     

给水车间污泥处理工程设计及调试

针对某给水车间沉淀池排泥水及滤池反冲洗排水SS较高的特点，设计采用沉淀浓缩及离心机脱水的方法，使排泥水处理后的清水回用或达标排放，脱水后的干泥外运填埋。系统试运行结果表明，沉淀池出水SS约7mg／L，离心机脱水后污泥含固率达到30％，离心机分离液SS≤200mg／L，处理能力和效果达到了设计要求，实现了节水、控制污染双重目的。     

河湖底泥资源化研究现状与展望

介绍了河湖底泥的矿物组成、污染来源、特性及危害,污染河湖底泥的处置原则和处置方法。阐明了目前底泥资源化技术研究现状,其中包括底泥土地利用、固化后做填方材料和制造建筑材料、制约底泥资源化利用方式的影响因素等,并对河湖底泥资源化的未来研究进行了总结和展望。     

Nutrient distribution and risk assessment in drainage ditches with different surrounding land uses

Due to lack of ditch maintenance, many ditches in the upper reaches of the Yangtze River are strongly affected by nutrient over-enrichment. Accordingly, we conducted surveys of nutrient concentrations in ditchwater and sediment in the hilly area of the central Sichuan Basin to investigate the spatiotemporal variations of nutrient concentrations and to promote the restoration of ditches for ecological functions. The results showed that the mean total nitrogen, particulate nitrogen, nitrate nitrogen, ammonia nitrogen, and total phosphorus values in ditchwater were 4.80, 1.09, 0.94, 1.09, and 0.18 mg/L, respectively. The mean concentrations of total nitrogen, nitrate nitrogen, ammonia nitrogen, and total phosphorus in ditch sediment were 1.58 g/kg, 2.62 mg/kg, 1.54 mg/kg, and 6.95 g/kg, respectively. Higher total nitrogen concentrations in ditchwater occurred in western areas, while higher total phosphorus concentrations occurred in central areas. Seasonally, we measured higher nitrogen and phosphorus concentrations in ditchwater close to agricultural areas during the rainy season, while the opposite effect was true for residential areas. Although nutrient concentrations in ditchwater could be affected by both surrounding land uses and ditch water levels, land use was critical. Moreover, nitrogen and phosphorus concentrations were significantly higher in the ditchwater near residential areas when compared to paddy or sloping cropland ditches. However, we found no significant differences between the nutrient contents of sediments in ditches surrounded by different land uses. Our results indicate that water pollution control initiatives in residential areas would be the most critical factor in combating ditchwater and sediment pollution in this region. Therefore, efforts to restore the ecological functions of drainage ditches should take into account rural township sewage management, fertilizer reduction, and especially ditch vegetation restoration.     

湖泊污染特征及其生物修复

湖泊水体的污染与修复是当今的研究重点.文章从湖泊的污染现状和污染特征,以及湖泊污染水体的主要修复措施进行了综述.对湖泊污染的特征主要从富营养化、有机有毒污染物污染以及重金属污染三个方面进行了阐述;对湖泊水体污染治理的工业工程措施和生物修复技术做了重点阐述,指出生物修复是湖泊污染水体修复的长期的,环保的修复方式,同时对于...     

PAH Distributions in Sediments from High Mountain Lakes

Abstract

The PAH distributions in sediment cores from eight remote lakes distributed over Europe have been investigated. All sites show a similar qualitative composition, being dominated by parent compounds from phenanthrene to coronene. Perylene, a diagenetically produced PAH, dominates the mixtures in deep sediment layers. The distribution and ratios of specific compounds indicate that these hydrocarbons are of pyrolitic origin, mainly from coal combustion processes, but contributions from other sources are also present (i.e., retene is probably indicative of wood combustion inputs). The qualitative differences due to inputs, sources or physico-chemical conditions are discussed.     

永川区卫星湖氨氮、化学需氧量污染现状与控制对策分析

文章简要介绍了卫星湖的自然环境,根据功能分区,在卫星湖设置5个监测断面分别在3月、9月、12月就生化需氧量,氨氮两项水质指标进行了检测分析。分析结果表明生化需氧量,氨氮两项指标均超过地表水Ⅲ类标准,调查显示产生的主要原因是农业面源污染,并针对农业面源控制提出相关的控制对策。     

济南卧虎山水库上游河流氮素含量时空变化特征研究

于2010年12月至2011年10月对济南南部重要水源地上游的锦阳川和锦云川两小流域地表水分季节地进行了系统采集,分析研究了河流水环境因子（水温、pH值、溶解氧、电导率）与水体铵态氮（NH4^＋-N）、硝态氮（NO3^--N）、总氮（TN）的时空变化特征。结果表明：锦阳川流域受旅游污染的影响,10月水体NH4^＋-N含量最高,锦云川流域则受周围农业活动的影响,8月NH4^＋-N含量较高;水体NO3^--N含量的季节变化表现为冬季〉秋季〉夏季〉春季;空间上,NH4^＋-N和NO3^--N沿水流方向基本呈逐渐升高的趋势;NO3^--N是流域氮素的主要稳定形态;河水中TN含量明显高于地表水环境质量的V类标准,说明该地区TN的污染已很严重,应作为重点污染物进行治理。     

太湖流域人工合成麝香的分布调查研究

采用超声辅助乳化-液液微萃取和快速溶剂萃取技术并结合气相色谱-质谱方法,分析检测了太湖水样和湖底沉积物中8种人工合成麝香含量。结果表明,太湖流域人工合成麝香污染物主要有佳乐麝香(HHCB)、吐纳麝香(AHTN)、二甲苯麝香(MX)和麝香酮(MK)。其中水样中的平均浓度分别为15.5ng/L、10.2ng/L、1.82ng/L、0.648ng/L;湖底沉积物中的平均含量分别为0.812ng/g、0.476ng/g、0.0842ng/g、0.0249ng/g。太湖流域与国内外其他地区的人工合成麝香污染水平相当,有关部门应引起注意。