鸭河口水库水体总氮、总磷预测研究

根据鸭河口水库受纳点源及面源污染负荷情况,选择枯水期为预测时期,采用迪隆模型对鸭河口水库水体总氮、总磷进行预测研究,为鸭河口水库水质保持和富营养化防治提供基础数据。     

Comparison of heavy metal loads in stormwater runoff from major and minor urban roads using pollutant yield rating curves

Trace metal export by stormwater runoff from a major road and local street in urban Sydney, Australia, is compared using pollutant yield rating curves derived from intensive sampling data. The event loads of copper, lead and zinc are well approximated by logarithmic relationships with respect to total event discharge owing to the reliable appearance of a first flush in pollutant mass loading from urban roads. Comparisons of the yield rating curves for these three metals show that copper and zinc export rates from the local street are comparable with that of the major road, while lead export from the local street is much higher, despite a 45-fold difference in traffic volume. The yield rating curve approach allows problematic environmental data to be presented in a simple yet meaningful manner with less information loss.     

Ozone patterns for three metropolitan statistical areas in North Carolina, USA

As part of an effort by the state of North Carolina to develop a State Implementation Plan (SIP) for 1-h peak ozone control, a network of ozone stations was established to monitor surface ozone concentrations across the state. Between 19 and 23 ozone stations made continuous surface measurements between 1993 and 1995 surrounding three major metropolitan statistical areas (MSAs): Raleigh/Durham (RDU), Charlotte/Mecklenburg (CLT), and Greensboro/High Point/Winston-Salem (GSO). Statistical averages of the meteorological and ozone data were performed at each Metropolitan Statistical Area (MSA) to study trends and/or relationships on high ozone days (days in which one of the MSA sites measured an hourly ozone concentration90.0 ppbv). County emission maps of precursor gases, wind roses, total area averages of ozone, total downwind averages of ozone deviations, upwind averages of ozone, and a modified delta ozone analysis were all obtained and analyzed. The results of this study show a reduction in the delta ozone relative to an earlier study at RDU, but no average significant change at CLT (no comparison can be made for GSO). The statistical data analyses in this study are used to quantify the importance of local contributions and regional transport, to ozone air pollution in the MSAs.     

The distribution characteristics of pollutants released at different cross-sectional positions of a river

The distribution characteristics of heavier or lighter pollutants released at different cross-sectional positions of a wide river is investigated with a well-tested three-dimensional numerical model of gravity flows based on Reynolds-Averaged Navier-Stokes equations and turbulence k-? model. By focusing on investigating the influences of flow and buoyancy on pollutants, it is found that while carrying by the river flow downstream: i) a heavier pollutant released from the cross-sectional side position, forms transverse oscillation between two banks with decreased amplitude, i.e. forms kind of helical flow pattern along the straight part of channel bed; ii) a heavier pollutant released from the cross-sectional middle position, forms collapse oscillation in the middle of the straight channel part with reduced amplitude; iii) in the downstream sinuous channel, heavier pollutant is of higher concentration on the outer side of channel bends; iv) a light pollutant released from the cross-sectional side position, slips partly to the other side of the river, resulting in higher concentrations on two sides of the channel top; v) a light pollutant released from the cross-sectional middle position, splits into two parts symmetrically along two sides of the channel top; vi) in the downstream sinuous channel, light pollutant presents higher concentration on the inner side of channel bends. These findings may assist in cost-effective scientific countermeasures to be taken for accidental or planned pollutant releases into a river.     

排污单位排污许可证申请说明示例研究

改革后排污许可制实施以来,积累了宝贵的经验和做法,也暴露出了技术层面操作的问题。文中从技术角度探讨分析排污单位的申请材料填报情况,结合有关要求创新性示范制定了“排污单位排污许可证申请说明”,以期做到排污单位“说得清”、核发单位“审得明”,提高排污许可证申请与核发效率。     

煤气发生站洗冷废水治理研究

研究了以活性炭作为吸附剂处理煤气发生站废水工艺,并摸索出一整套的工艺参数。实验结果表明,采用活性炭吸附工艺使出水水质得到明显改观,硫化物、氰化物和挥发酚的去除效率均达９０％以上,对ＣＯＤｃｒ、氨氮的去除也收到了明显的效果。     

Indoor pollutant mixing time in an isothermal closed room: an investigation using CFD

We report on computational fluid dynamics (CFD) predictions of mixing time of a pollutant in an unventilated, mechanically mixed, isothermal room. The study aims to determine: (1) the adequacy of the standard Reynolds Averaged Navier Stokes two-equation (k−) turbulence model for predicting the mixing time under these conditions and (2) the extent to which the mixing time depends on the room airflow, rather than the source location within the room. The CFD simulations modeled the 12 mixing time experiments performed by Drescher et al. (Indoor Air 5 (1995) 204) using a point pulse release in an isothermal, sealed room mechanically mixed with variable power blowers. Predictions of mixing time were found in good agreement with experimental measurements, over an order of magnitude variation in blower power. Additional CFD simulations were performed to investigate the relation between pollutant mixing time and source location. Seventeen source locations and five blower configurations were investigated. Results clearly show large dependence of the mixing time on the room airflow, with some dependence on source location. We further explore dependence of mixing time on the velocity and turbulence intensity at the source location. Implications for positioning air-toxic sensors in rooms are briefly discussed.     

Experimental and numerical study of the dispersion of motor vehicle pollutants under idle condition

The aim of the work presented here is to study experimentally and numerically the dispersion characteristics of vehicular exhaust plume at an idle condition in an idealized and simplified environment. The gaseous and particulate concentrations in the exhaust plume of three idling motor vehicles were measured in an isolated environment under calm weather conditions. Despite the difference in the initial concentrations, the pollutants decayed exponentially in all directions.The CFD code PHOENICS 3.3, with the k–ε eddy dissipation sub-model, was used for the numerical simulation. The simulated results match very well with the experimental results close to the source of emission but decay to the ambient concentrations much slower. The effects of the initial emission concentration, exit velocity, exit direction and crosswind intensity have been investigated parametrically. The initial pollutant concentration will increase the local concentrations but the pattern of dispersion remains the same. The exit velocity will increase the momentum of the jet, resulting in a deeper penetration downstream. The exit angle has a stronger influence on pollutant dispersion than both initial pollutant concentration and exit velocity. When the exit angle is 15°, the pollutants tend to spread on the ground region. Crosswind shows a significant effect on the dispersion of the exhaust plume also. It will divert the plume to disperse in the same direction of the wind with limited penetration in the downstream direction.     

Identification of two new cytochrome P450 genes and RNA interference to evaluate their roles in detoxification of commonly used insecticides in Locusta migratoria

Composite samples of Australian farmed Yellowtail Kingfish (Seriola lalandi) (YTKF) (n = 27), Mulloway (Argyrosomus hololepidotus) (n = 6) and manufactured feed (n = 5) were analysed to benchmark levels of a broad range of residues and contaminants of potential public health and trade significance. A subset of these samples [YTKF (n = 5), Mulloway (n = 2) and feed (n = 5)] was analysed for dioxins and polychlorinated biphenyls (PCBs). The mean concentration of dioxins in YTKF was 0.6 pg TEQ g⁻¹ (range 0.22-0.8) and in Mulloway was 0.16 pg TEQ g⁻¹ (range 0.16-0.16). The mean concentration of dioxins and dioxin-like PCBs in YTKF was 2.6 pg TEQ g⁻¹ (range 1.4-3.5), while Mulloway had a mean concentration of 0.67 pg TEQ g⁻¹ (range 0.57-0.76). The mean concentration of PCBs in YTKF was 21 μg kg⁻¹ (range 8.6-29) and in Mulloway was 5.4 μg kg⁻¹ (mean 4.7-6). The mean concentration of dioxin-like PCBs in YTKF was 2.1 pg TEQ g⁻¹ (range 1.2-2.8) and in Mulloway was 0.51 pg TEQ g⁻¹ (range 0.41-0.61). The mean mercury concentration in YTKF was 0.03 mg kg⁻¹ (range 0.02-0.05) and in Mulloway it was 0.02 mg kg⁻¹ (range 0.02-0.04). There were no detectable levels of any pesticide or antimicrobial compounds in any sample of YTKF or Mulloway. Attention is drawn to technical differences in port of entry testing programs such as sampling strategies, portion tested, laboratory methodology, residue definitions and reporting conventions that exporters’ products may be subject to. All residues and contaminants were either undetectable or present at very low levels when judged against Australian, Japanese and European Union regulatory standards (where set).     

Rapid measurement of indoor mass-transfer coefficients

Indoor air pollutant concentrations can be influenced by how rapidly species are transported to and from surfaces. Consequently, a greater understanding of indoor transport phenomena to surfaces improves estimates of human exposure to indoor air pollutants. Here, we introduce two methods of rapidly and directly measuring species fluxes at indoor surfaces, allowing us to evaluate the transport-limited deposition velocity, v_t (a mass-transfer coefficient). The deposition velocity sensor (DeVS) method employs a small microbalance coated with a pure hydrocarbon, preferably octadecane. We quantify flux (or evaporation rate) of the hydrocarbon into a room by observing the rate of mass loss on the microbalance. The transport-limited deposition velocity, v_t,octadecane, is then obtained by combining the flux with the vapor pressure of the hydrocarbon. Simultaneously, v_t,ozone is quantified using the deposition velocity of ozone (DeVO) method, which acts as a standard to calibrate and evaluate DeVS. Specifically, DeVO evaluates ozone transport to surfaces by quantifying the conversion by ozone of nitrite to nitrate on a glass fiber filter. Simultaneous laboratory chamber experiments demonstrates that v_t for octadecane and ozone are strongly correlated, with the values for ozone 1.5 times greater than that for octadecane. In an office experiments, the DeVS method responds within minutes to step changes in conditions such as occupancy, activities and ventilation. At present, the results are in order-of-magnitude agreement with predicted indoor mass-transfer coefficients.     

A dynamic modelling approach for estimating critical loads of nitrogen based on plant community changes under a changing climate

A dynamic model of forest ecosystems was used to investigate the effects of climate change, atmospheric deposition and harvest intensity on 48 forest sites in Sweden (n = 16) and Switzerland (n = 32). The model was used to investigate the feasibility of deriving critical loads for nitrogen (N) deposition based on changes in plant community composition. The simulations show that climate and atmospheric deposition have comparably important effects on N mobilization in the soil, as climate triggers the release of organically bound nitrogen stored in the soil during the elevated deposition period. Climate has the most important effect on plant community composition, underlining the fact that this cannot be ignored in future simulations of vegetation dynamics. Harvest intensity has comparatively little effect on the plant community in the long term, while it may be detrimental in the short term following cutting. This study shows: that critical loads of N deposition can be estimated using the plant community as an indicator; that future climatic changes must be taken into account; and that the definition of the reference deposition is critical for the outcome of this estimate.     

An empirical map of critical loads of acidity for soils in Great Britain

The method used to produce a critical load map of acidity for soils in Great Britain is described. Critical loads were assigned to the dominant soil in each 1 km grid square of the UK national grid. Mineral soils were assigned a critical load based on mineralogy and chemistry, using approaches appropriate to UK conditions. Critical loads for peat soils are based primarily on a maximum acceptable reduction of peat pH, and results from laboratory equilibration studies. The map shows that soils with small critical loads (<0.5 kmol_c ha⁻¹ year⁻¹) i.e. highly sensitive to acidic deposition, dominate in the north and west of Britain; the south and east are dominated by soils with large critical loads, with small areas of more sensitive soils associated with sandy soil-forming materials. A modified critical load map illustrates the potential impact of agricultural liming on soil critical loads.     

Geographic variation in tissue accumulation of endocrine disrupting compounds (EDCs) in grazing sheep

Muscle tissue was collected from ewes and lambs derived from farms throughout Scotland and sample concentrations of five endocrine disrupting compound groups were determined. Farms of origin were categorised according to geographic region. There were few statistically-significant differences with region or distance from cities. However, the magnitude of the difference between the highest and lowest mean values in ewe muscle from different regions exceeded 30% for 13 of the 15 compounds that were consistently detected in muscle, with animals derived from the industrialised region having the highest mean values for 11 of the 13 compounds. A less marked trend was apparent in the lamb muscle (8 of 13 highest were in the industrialised region). The physiological effects of such small differences in exposure to mixtures of pollutants remain to be determined.     

Assessment of uncertainties in a long range atmospheric transport model: Methodology, application and implications in a UK context

Acid deposition models are inherently simplified representations of real world behaviour and their performance is best evaluated by comparison with observations. National and international acid rain policy assessments handle observed and modelled deposition fields in different ways. Here, both the observed and modelled deposition fields are seen as uncertain and the Generalised Likelihood Uncertainty Estimation (GLUE) framework is used to choose acceptable sets of model input parameters that minimise the differences between them. These acceptable sets of model parameters are then used to estimate deposition budgets to the UK and to provide a probabilistic treatment of excess deposition over environmental quality standards (critical loads).     

Distribution of polycyclic aromatic hydrocarbons in urban stormwater in Queensland, Australia

This paper reports the distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in wash-off in urban stormwater in Gold Coast, Australia. Runoff samples collected from residential, industrial and commercial sites were separated into a dissolved fraction (<0.45 μm), and three particulate fractions (0.45-75 μm, 75-150 μm and >150 μm). Patterns in the distribution of PAHs in the fractions were investigated using Principal Component Analysis. Regardless of the land use and particle size fraction characteristics, the presence of organic carbon plays a dominant role in the distribution of PAHs. The PAHs concentrations were also found to decrease with rainfall duration. Generally, the 1- and 2-year average recurrence interval rainfall events were associated with the majority of the PAHs and the wash-off was a source limiting process. In the context of stormwater quality mitigation, targeting the initial part of the rainfall event is the most effective treatment strategy. The implications of the study results for urban stormwater quality management are also discussed.     

CANON工艺的典型抑制及其恢复性策略

全程自养脱氮(CANON)工艺在110 d时,总氮去除负荷(NRR)达到了1.8 kg N/(m3·d)。在高溶解氧(DO)的条件下,CANON工艺脱稳失活,脱氮性能急剧下降,ANAMMOX菌受到抑制。采取减少曝气量,降低反应器中的DO,可以有效恢复CANON工艺的脱氮性能。在第327天时,进水氨氮浓度高达1 245.5 mg/L,氨氮和总氮去除效率分别达到98.4%和80.3%,而NRR高达了1 kg N/(m3·d)。此后,CANON工艺脱氮效果较为稳定,表明CANON工艺恢复效果明显。SEM分析表明,颗粒污泥表面附着大量的短杆状细菌,细菌之间联系紧密,部分颗粒污泥表面呈现网状结构,细菌之间通过丝状物联系形成颗粒污泥。能谱分析表明,颗粒污泥表面含有O、Na、P、Fe、Ca、C和Si等元素。     

降雨促渗对地表径流污染物负荷影响模拟试验研究

建立模拟降雨装置,研究降雨条件下功能性材料与聚合物对降水土壤渗透性与地表径流污染负荷的影响.研究证实,沸石与PAM不仅能够促进降雨土壤水的入渗、延缓并减少地表径流,而且使土壤渗液和地表径流水质TSS、TN、TP、COD污染物负荷降低.以3 kg/hm2 PAM、3 kg PAM与7.5 t/hm2沸石、6 kg/hm2 PAM 3种方式处理,径流COD负荷为对照的39.12%～69.76%、26.14%～46.63%和20.60%～28.09%;TN、TP与TSS负荷较对照分别减少44.36%～96.47%、66.63%～98.99%、93.71%～99.62%和50.46%～98.40%、83.30%～99.31%、94.91%～99.72%和31.06%～77.23%、46.82%～86.22%、83.54%～95.33%.聚合物与功能性材料改良土壤是一种削减地表降雨径流非点源污染的有效手段.     

污染负荷及植被生物量变化对缓冲带污染物净化效果的影响

模拟上海地区农业面源污染和降雨特征,进行缓冲带污染物净化效果和植被生物量监测试验研究。结果表明：植被缓冲带对径流污染物质的净化效果明显高于空白对照,百慕大缓冲带SS截留率最高,达到74％;白花三叶草对TN、TP的净化效果最好,去除率分别为28％和25％;百慕大和白花三叶草生物量最大,栽种当年9月份,两者地上部分的生物量鲜重分别达到了6.14和6.49 kg/m²,百慕大生长速度最快,当年9月份生物量几乎达到5月份的6倍;植被生物量增长明显提高了缓冲带截留径流污染物的效果,缓冲带SS截留率与生物量成显著线性相关,而污染负荷变化对缓冲带污染物净化效果的影响很小,明显弱于植被种类和生物量的变化。     

降雨促渗对地表径流污染物负荷影响模拟试验研究

建立模拟降雨装置，研究降雨条件下功能性材料与聚合物对降水土壤渗透性与地表径流污染负荷的影响。研究证实，沸石与PAM不仅能够促进降雨土壤水的人渗、延缓并减少地表径流．而且使土壤渗液和地表径流水质TSS、TN、TP、COD污染物负荷降低。以3kg／hm^2PAM、3kgPAM与7．5t／hm^2沸石、6kg／hm^2 PAM3种方式处理，径流COD负荷为对照的39．12％-69．76％、26．14％-46．63％和20．60％-28.09％；TN、TP与TSS负荷较对照分别减少44．36％-96．47％、66．63％-98．99％、93．71％-99．62％和50．46％～98．40％、83．30％～99．3l％、94．91％～99．72％和31．06％～77．23％、46．82％，86．22％、83．54％-95.33％。聚合物与功能性材料改良土壤是一种削减地袁降雨径流非点源污染的有效手段。