小麦/玉米轮作体系中不同施肥方法下的养分淋溶排污系数测算

为粮田耕地污染监控预警及污染控制提供技术支持,以北京市房山区小麦/玉米轮作为研究对象,采用陶土头负压法,通过2年的田间小区对比试验,以不施肥处理为对照,分析比较优化施肥和常规施肥对淋溶液水质的影响,并测算不同施肥处理的排污系数。研究结果表明:不同的施肥处理氮素淋溶量占总养分淋溶的76%~82%,氮素淋溶中以硝态氮为主,占总氮素淋溶的60%~70%,最高可达到90%;在氮磷钾养分施入量相同的情况下,优化施肥处理在不同程度上降低了养分淋溶量,可使总氮淋溶量减少23%~31%,总磷淋溶量减少32%~46%,硝态氮淋溶量减少22%~36%,在降雨量大时,优化施肥处理可明显减少铵态氮的淋溶;经测算,小麦/玉米轮作农田耕地排污系数(产出每公斤农产品养分淋溶排出量)常规施肥处理总氮、总磷、铵态氮及硝态氮的排放量分别为687.2、3.25、0.22、440 mg,优化施肥处理的排放量分别为348、0.87、0.38、205.9 mg。     

兴山县香溪河流域农业源氮磷排放估算及时空特征分析

基于典型调查与统计分析,应用排污系数法估算了兴山县香溪河流域2007-2013年种植业源、畜禽养殖业源和农村生活源TN、TP污染物的排放量,并对排放量、排放强度及其时空格局进行了分析。结果表明,香溪河流域农业面源污染TN、TP年均排放量分别为 1 145.2、56.5 t·a^-1,排放强度分别为44.5、2.14 kg·hm^-2·a^-1.农业源TN和TP的年排放量逐年增加,2013年较2007年增幅分别为38.0%和85.1%,TN:TP为21:1,TN排放占主导,为香溪河流域兴山县段重点防控指标。从各类污染源贡献来看,畜禽养殖业源是TN的主要贡献源,占农业源污染总量的77.9%;种植业源是TP的主要贡献源,占55.4%.从不同源氮磷排放量空间格局来看,各乡镇中水月寺镇、黄粮镇和峡口镇的TN、TP排放量均最高。从氮磷排放强度空间格局来看,峡口镇、高桥乡和黄粮镇对TN排放强度最高;峡口镇、昭君镇和黄粮镇对TP排放强度最高。     

气阻致输油泵机械密封过热失效分析与对策

西部管道乌鲁木齐输油首站成品油主泵启输及运行中多次出现机械密封泄漏油气油烟的过热失效现象。针对该问题,通过对机械密封失效现象的观察、气阻机理的探讨以及对气阻和杂质堵塞致机械密封失效的现象和原因进行对比分析,确定了气阻是导致机械密封过热失效泄漏油气油烟的主因。同时,提出了机械密封过热失效的解决方法,包括：启泵前需要反复多次对泵腔灌泵以充分排气;运行过程中若发现机械密封压盖及冲洗冷却循环管路快速升温发烫,则应立即在不停泵的状态下缓开泵腔排气阀排气。相关经验可为输油站现场避免发生此类问题提供实践依据。（图2,参6）     

河南省沙颍河流域畜禽养殖污染负荷研究

为了解河南省沙颍河流域畜禽养殖业对环境的污染状况,在流域内平顶山、漯河、许昌、郑州、周口5市所辖区域选择猪、鸡、牛的典型养殖场,分季节采集污水和粪尿,进行化学需氧量（COD）、氨氮（NH3 N）含量检测,计算排污系数,结合各市耕地面积,估算畜禽粪便耕地负荷,采用畜禽粪便负荷警报分级方法评价畜禽养殖环境污染状况。结果表明：沙颍河流域内畜禽养殖量占河南省畜禽养殖总量的25·19％,畜禽个体排污系数以牛最大,其次是猪、鸡,流域内年产生畜禽污染物总量为7529·414万 t,各市畜禽污染物产生量大小依次为：周口、平顶山、许昌、郑州、漯河;流域内单位耕地面积平均畜禽粪便负荷为33·07 t/hm2,NH3 N 耕地负荷为43·47 kg/hm2;畜禽粪便负荷警报值在0·51～1·19,警报值级别为Ⅱ～Ⅳ级,其中以平顶山最为严重。说明河南省沙颍河流域内5市的畜禽养殖污染物已经对环境构成了不同程度的污染。     

半导体工业废水污染特征因子初探

指出了集成电路和印制电路板是半导体工业的主要组成部分,而在生产过程中会大量使用氢氟酸,使得虽经过处理后的生产废水中氟离子浓度仍较高,达到7 mg/L左右;通过将半导体企业排放废水与生活污水、地下水及地表水中氟离子浓度进行比较,提出了以氟离子浓度作为半导体工业废水的污染特征因子,并结合不同雨污混接类型污染特征因子,依据物料和水量守恒得出不同混接类型的近似混接水量比例计算公式,以期为后续的雨污混接溯源和雨污改造工程提供借鉴。     

广西规模化猪场2种主要排污模式的指标测定

应用常规的化学分析技术,测定了广西地区具有代表性的2个规模化猪场不同污水处理阶段的污染物含量,并与国家排放标准进行比较,研究每个处理环节污染指数的变化,从而为畜牧养殖业节能减排采取针对性的整改措施提供参考。污染物指标包括:悬浮物(SS)、氨氮(NH3-N)、五日生化需氧量(BOD5)和化学耗氧量(CODcr)。结果表明,2个规模化猪场排出的污水经过一定的污水处理工艺后,猪场1排放的污水不达标,猪场2排放的污水达标;植物塘对污水有明显的净化作用;沉淀调节池和二沉池环节都能有效降低悬浮物(SS)的指标。     

HPLC-PDA法测定兽药中非法添加四种解热镇痛抗炎类药物

建立了7种兽药中非法添加对乙酰氨基酚、安乃近、地塞米松和地塞米松磷酸钠药物的HPLC-PDA法。采用十八烷基键合硅胶为填充剂,磷酸二氢钠缓冲液（磷酸二氢钠3．0 g加水至1000 mL,加三乙胺1 mL,用氢氧化钠调pH值至7．0±0．2）-甲醇（80∶20）为流动相,梯度洗脱,二极管阵列检测器进行全扫描和240 nm波长测定,并采用峰纯度检查和光谱相似度检查辅助对照品比对方法,对四种目标分析物进行确证。结果显示,4种解热镇痛抗炎药物与其他物质峰分离良好,在测定范围内线性关系良好,平均回收率为73．5％～119．2％,RSD为0．1％～5．8％。本方法准确、可靠、重现性好,可用于兽药制剂中非法添加四种解热镇痛抗炎药物的定性和定量检测。     

Intake and discharge nutrient loads at three intensive shrimp farms

This study was conducted to help provide a framework for Australian regulation of shrimp farm siting and discharges. Monitoring of farm water usage, and intake and discharge water quality was conducted at three commercial intensive shrimp farms, chosen to represent different operating environments, latitudes, cultured species and management styles. Weekly samples were taken over 3 years, for 3–12 months at each farm, to investigate intake and discharge concentrations and loads of total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP). Mean water exchange was 1.4 ML ha^?1 day^?1 (about 10% day^?1) at the first farm studied and 0.5 ML ha^?1 day^?1 (about 3.6% day^?1) at the others. Farm mean discharge concentration varied as follows: TSS, from 36.9 to 119 mg L^?1; TN, from 2.1 to 3.1 mg L^?1 and TP, from 0.22 to 0.28 mg L^?1. Farm mean intake concentrations were from 11% to 91% of equivalent mean discharge concentration (for TN at Farm B and TSS at Farm C respectively). Mean net discharge loads, related to area of production ponds at each farm, varied as follows: TSS, from 4.8 to 85.7 kg ha^?1 day^?1; TN, from 1 to 1.8 kg ha^?1 day^?1 and TP, from 0.11 to 0.22 kg ha^?1 day^?1. The highest net loads of TSS, TN and TP were all from the farm with the highest water exchange rate, located on a coastal river, and studied during a year of high rainfall with associated poor water quality. These results can be used to help predict likely discharge characteristics for new shrimp farms, and provide a benchmark against which to evaluate future improvements in shrimp farm environmental management.     

Floodplains of a regulated southern alpine river (Brenno,Switzerland): ecological assessment and conservation options

• 1. The fifth‐order southern alpine Brenno River and its floodplains are severely impaired by embankments, water abstractions and the construction of dams for hydropower generation. The river's annual mean discharge is reduced to 27% of the natural flow and the number of small (50–100 m³ s^?1) and medium‐sized (101–150 m³ s^?1) floods is reduced significantly.
• 2. Lateral hydrological connectivity has decreased strongly as a result of the flow regulation, whereas the significance of vertical connectivity has increased. The remnants of the middle and lower floodplains still contain springbrooks, ponds, and intermittently connected channels, which are all sustained by emerging groundwater.
• 3. Aquatic floodplain habitats can be classified partially by faunal composition. The lotic/lentic gradient appears to be a dominant compound factor structuring invertebrate assemblages when considering all aquatic habitats. The exfiltration of groundwater in conjunction with a reduced lateral connectivity enables the occurrence of many stenotopic species.
• 4. A comparison of present floodplains with those shown on historical maps shows that the fluvial landscape has changed markedly. The proportions of functional floodplain units characterized by autogenic succession and trends to late successional stages (i.e. senescence) have increased.
• 5. Floodplains of the Brenno river are still considered to represent important ecological areas and they are protected by law. Whilst the legislative protection of floodplains is the basis for conservation, this does not include the restoration of driving hydrological processes. An annual release of small‐ and medium‐sized floods could generate a diversity of disturbances, thereby promoting rejuvenation and counteracting senescence.
• 6. Alternative conservation options that circumvent ongoing contracts of water use, though generally promising, are limited because of the operation of hydropower schemes. At present the exfiltrations of groundwater mitigate the impacts of flow regulation on the ecological integrity of the floodplains.

Copyright © 2002 John Wiley & Sons, Ltd.     

Condition assessment of lamprey populations in the Yorkshire Ouse catchment,north‐east England,and the potential influence of physical migration barriers

• 1. River lamprey (Lampetra fluviatilis) and sea lamprey (Petromyzon marinus) are designated features of the River Derwent Special Area of Conservation (SAC) and the Humber Estuary (a possible SAC). This study determined the condition of lamprey populations in the Yorkshire Ouse catchment by assessing the species composition, distribution, abundance and size‐structure of larval (ammocoete) populations in five major tributary rivers (Derwent, Swale, Ure, Nidd and Wharfe).
• 2. According to EU condition assessment criteria, Lampetra populations (assumed to be mostly river lamprey) are at present in favourable condition, with site mean (±SE) densities ranging from 2.7 (±1.2) to 160.3 (±50.5) individuals m^?2 (all river means >2 individuals m^?2), and at least two size (≈age) classes present in optimal microhabitats. By contrast, no sea lamprey larvae were recorded, suggesting that populations of this species are in unfavourable condition.
• 3. Actions to protect and enhance nationally or internationally important stocks must be implemented from at least a catchment perspective, because many of the issues affecting such species are not localized. With respect to lampreys, particular attention should be given to protecting spawning and nursery habitats, improving water quality, reducing impingement at abstraction points, preventing exploitation at spawning grounds and increasing passage at potential physical obstructions.

Copyright © 2007 John Wiley & Sons, Ltd.