Development and implementation of coral reef biocriteria in U.S. jurisdictions

Coral reefs worldwide are declining at an alarming rate and are under continuous threat from both natural and anthropogenic environmental stressors. Warmer sea temperatures attributed to global climate change and numerous human activities at local scales place these valuable ecosystems at risk. Reefs provide numerous services, including shoreline protection, fishing, tourism and biological diversity, which are lost through physical damage, overfishing, and pollution. Pollution can be controlled under provisions of the Clean Water Act, but these options have not been fully employed to protect coral reefs. No U.S. jurisdiction has implemented coral reef biocriteria, which are narrative or quantitative water quality standards based on the condition of a biological resource or assemblage. The President’s Ocean Action Plan directs the U.S. Environmental Protection Agency (EPA) to develop biological assessment methods and biological criteria for evaluating and maintaining the health of coral reef ecosystems. EPA has formed the Coral Reef Biocriteria Working Group (CRBWG) to foster development of coral reef biocriteria through focused research, evaluation and communication among Agency partners and U.S. jurisdictions. Ongoing CRBWG activities include development and evaluation of a rapid bioassessment protocol for application in biocriteria programs; development of a survey design and monitoring strategy for the U.S. Virgin Islands; comprehensive reviews of biocriteria approaches proposed by states and territories; and assembly of data from a variety of monitoring programs for additional metrics. Guidance documents are being prepared to assist U.S. jurisdictions in reaching protective and defensible biocriteria.     

Comprehensive monitoring of drinking well water quality in Seoul metropolitan city, Korea

In this research, the quality of drinking well waters from 14 districts around Seoul metropolitan city, Korea was assessed by measuring a number of parameters with established guideline (e.g., arsenic, fluoride, nitrate nitrogen, benzene, 1,2-dichloroethene, dichloromethane, copper, and lead) and without such criteria (e.g., hardness, chloride ion, sulfate ion, ammonia nitrogen, aluminum, iron, manganese, and zinc). Physical parameters such as evaporation residue (or total dissolved solids) and turbidity were also measured. The importance of each parameter in well waters was examined in terms of the magnitude and exceedance frequency of guideline values established by international (and national) health agencies. The results of this study indicate that among the eight parameters with well-established guidelines (e.g., WHO), arsenic and lead (guideline value of 0.01 mg?L^?1 for both) recorded the highest exceedance frequency of 18 and 16 well samples ranging in 0.06–136 and 2–9 mg?L^?1, respectively. As such, a number of water quality parameters measured from many well waters in this urban area were in critical levels which require immediate attention for treatment and continuous monitoring.     

对本溪市生态环境问题的探讨

简述了“十五”期间本溪市生态环境质量的现状、特点、趋势;以及生态保护、生态建设的情况。提出了生态环境问题的防治对策。     

Designing reverse-flow packed bed reactors for stable treatment of volatile organic compounds

Reverse-flow packed bed reactors can be used to treat gaseous pollutants from chemical plants. This article describes the design and operation of a modified reverse-flow reactor (MRFR) which has a recuperator on each end of the reactor and a reaction zone in the middle. The recuperators have low thermal dispersion and the reaction zone has a high thermal dispersion, obtained by placing metal inserts into the bed, parallel with the gas flow. Performance of the MRFR during extended lean and rich conditions is determined with analytical analysis and compares well with numerical simulations of CO oxidation; however, the theory is expected to be useful for any reaction kinetics. A major advantage of this MRFR design is an extended time for the reactor to extinguish during lean conditions. This work also describes MRFR performance with internal reactor cooling, which can be used as a control mechanism to maintain reactor temperature for proper removal of volatile organic compounds.     

Anthropogenic N2O production from landfill leachate treatment

The results of a field survey and laboratory study indicated that nitrogenous landfill leachate treatment can be a significant potential source of N2O emission. Nil (raw leachate) to 58.8ngmL(-1)h(-1) (sequential batch reactor) N2O emission was detected at five treatment plants in South China. The production and emission of N2O was especially high soon after the raw leachate was aerated. The emission was positively correlated with the dissolved N2O content in leachate; detected dissolved N2O ranged from 0 to 1309ngmL(-1). All leachate treatment plants studied were effective in NH4+-N removal (>95%); however, the highest N2O emission was estimated to be 0.25g N2Ocapita(-l)year(-1), comparable with the rate of N2O emission in conventional sewage treatment process.     

Comparison of DAYCENT-simulated and measured nitrous oxide emissions from a corn field

Accurate assessment of N(2)O emission from soil requires continuous year-round and spatially extensive monitoring or the use of simulation that accurately and precisely predict N(2)O fluxes based on climatic, soil, and agricultural system input data. DAYCENT is an ecosystem model that simulates, among other processes, N(2)O emissions from soils. The purpose of the study was to compare N(2)O fluxes predicted by the DAYCENT model to measured N(2)O fluxes from an experimental corn field in central Iowa. Soil water content temperature and inorganic N, simulated by DAYCENT were compared to measured values of these variables. Field N(2)O emissions were measured using four replicated automated chambers at 6-h intervals, from day of year (DOY) 42 through DOY 254 of 2006. We observed that DAYCENT generally accurately predicted soil temperature, with the exception of winter when predicted temperatures tended to be lower than measured values. Volumetric water contents predicted by DAYCENT were generally lower than measured values during most of the experimental period. Daily N(2)O emissions simulated by DAYCENT were significantly correlated to field measured fluxes; however, time series analyses indicate that the simulated fluxes were out of phase with the measured fluxes. Cumulative N(2)O emission calculated from the simulations (3.29 kg N(2)O-N ha(-1)) was in range of the measured cumulative N(2)O emission (4.26 +/- 1.09 kg N(2)O-N ha(-1)).     

城市机动车排放因子隧道试验研究

选取典型城市隧道进行机动车排放因子测试,应用隧道试验原理,通过连续48h的现场采样监测,获得了隧道内机动车排放污染物NO_x.CO、SO₂、PM₁₀、VOC和HC浓度、交通参数(车型、车速、交通流量)和气象参数(如风速、风量、温度、湿度)等实测数据.通过质量平衡计算出隧道内机动车NO_x.CO、SO₂、PM₁₀和HC的平均排放因子分别为1.379、15.404、0.142、0.637、1.857g·(km·辆)^-1.并在此基础上应用多元回归方法计算出8大类机动车各种排放污染物的单车排放因子.结果反映目前中国城市机动车污染物排放水平及各污染物排放特征.     

基于向量相似度原理的湖泊富营养化评价方法及其验证

为准确评价湖泊所处的营养状态,提出了基于向量相似度原理的湖泊富营养化评价方法.将富营养化的各级评价标准视为1个特征向量并进行无量纲化处理,然后计算各级特征向量与实测水质指标向量的相似度,归一化后得出各级评价标准对实测水质指标的权重,加权平均即可得出实测水质指标的富营养化综合评价级别.经全国30个湖库湖泊实测水质资料验证,向量相似度方法与随机评价方法、模糊评价方法、灰色评价方法相比较,有27个湖泊评价结果的差异不大于1个级别,其比例为90%.这说明4种方法的计算精度相当.     

不同燃料汽车排放超细微粒特性的实验研究

利用底盘测功机和粒径范围0.015~0.7 m的扫描迁移微粒测定仪 SMPS,对柴油出租车、柴油小巴车、汽油私家车和LPG出租车进行了高低怠速和10 kmh-1到70 kmh-1不同运行工况条件下排放的超细微粒粒径分布试验研究。研究表明：不同燃料车在不同工况条件下排放的细微粒尤其是超细微粒特征呈现显著的不同。柴油车贡献更多的是粒径在30～150 nm的核模态和积聚模态微粒,LPG和汽油车贡献更多的是15～30 nm的核模态微粒。总体上,柴油车比汽油车和LPG燃料车排放更多的微粒数和微粒质量;柴油车、汽油车和LPG车排放的SMPS可测细微粒总数、总质量分别约为(0.3~3.6) 108 cm-3,0.03~0.6 gcm-3;2.3×104~1.2×107 cm-3,8×10-5~0.1 gcm-3; 8.2×103~8.8×106 cm-3, 1.7×10-5~0.09 gcm-3;对所有测试汽车,在低怠速和低行驶速度时,排放微粒数少,在高怠速和高行驶速度时,排放微粒数多。     

原电池驱动污染高岭土中镉的电动力学迁移

以铁屑和活性炭构建的原电池研究不同电极间距下高岭土中的镉在原电池电场下的电动力学迁移.随着反应时间的延长,电压和电流均逐渐减小.反应后,高岭土的pH值从阳极到阴极逐渐增加.高岭土中镉含量从阳极向阴极逐渐增加,镉的去除率随电极间距的增加而降低,高岭土的pH值愈低镉的迁移效果愈明显.10cm的电极间距高岭土中镉的去除率达77.9%,在50cm的电极间距下镉的迁移作用很小.表明利用铁炭原电池产生的电场可以驱动污染高岭土中镉的电动力学迁移.