基于遗传算法优化的大气质量评价的污染危害指数公式

基于污染危害率概念,提出了大气环境质量评价的污染危害指数计算公式和新的因子赋权法．指出用污染物的浓度相对值代替其监测值,公式中的参数可认为不随污染物种类和数目而改变．采用遗传算法对公式中的参数进行优化,得到了适用于多种污染物的大气质量评价的污染危害指数计算公式应用该公式对实例评价的结果与用其他多种方法评价结果进行了比较结果表明,该公式用于大气环境质量评价的物理意义明确、普适性强、计算简单、使用方便．     

Watershed Evapotranspiration Increased due to Changes in Vegetation Composition and Structure Under a Subtropical Climate1

Abstract: Natural forests in southern China have been severely logged due to high human demand for timber, food, and fuels during the past century, but are recovering in the past decade. The objective of this study was to investigate how vegetation cover changes in composition and structure affected the water budgets of a 9.6‐km² Dakeng watershed located in a humid subtropical mountainous region in southern China. We analyzed 27 years (i.e., 1967‐1993) of streamflow and climate data and associated vegetation cover change in the watershed. Land use/land cover census and Normalized Difference of Vegetation Index (NDVI) data derived from remote sensing were used to construct historic land cover change patterns. We found that over the period of record, annual streamflow (Q) and runoff/precipitation ratio did not change significantly, nor did the climatic variables, including air temperature, Hamon’s potential evapotranspiration (ET), pan evaporation, sunshine hours, and radiation. However, annual ET estimated as the differences between P and Q showed a statistically significant increasing trend. Overall, the NDVI of the watershed had a significant increasing trend in the peak spring growing season. This study concluded that watershed ecosystem ET increased as the vegetation cover shifted from low stock forests to shrub and grasslands that had higher ET rates. A conceptual model was developed for the study watershed to describe the vegetation cover‐streamflow relationships during a 50‐year time frame. This paper highlighted the importance of eco‐physiologically based studies in understanding transitory, nonstationary effects of deforestation or forestation on watershed water balances.     

污泥龄对LSP & PNR污泥减量新工艺运行效能的影响

通过研究分析污泥龄（SRT）对富磷污水除磷的LSP&PNR污泥减量新工艺运行效果的影响,结果发现,延长污泥龄有利于提高系统的厌氧释磷能力,但不影响其总的除磷率,同时磷的回收比例增大,当SRT=50 d时,磷回收率取得最大值70.4％;LSP&PNR系统污泥龄增加,还有利于污泥产率的降低。试验还发现,排富磷污水除磷的长污泥龄LSP&PNR系统的除磷效率与污泥产率之间不存在制约关系,即系统可以同时获得优异的污泥减量与生物除磷效果,当SRT=50 d时,每降解1 kg COD仅产生0.143 kg污泥,而除磷率达最高值928％;LSP&PNR系统中SRT、DO与SVI之间存在一定的相关性,在供氧充足（DO＝0.8～1.5 mg/L）条件下,SRT增加,SVI越高,但对于SRT为50 d的LSP&PNR系统,稳定运行时没有污泥膨胀之虞。     

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface soils from the Qinghai-Tibetan plateau

Eighty eight surface soil samples were collected from the Qinghai-Tibetan Plateau (QTP) for determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs). The measured concentrations were 51.8 ± 38.5 ng g(-1), 0.329 ± 0.818 ng g(-1), and 0.467 ± 0.741 ng g(-1) as means and standard deviations of PAHs, DDXs, and HCHs, respectively, which were 1-2 orders of magnitude lower than those reported for eastern China. Significant differences were also revealed among four sub-areas within QTP. PAHs detected in the samples from the remote sub-areas of T'ang-ku-la/Hoh Xil Mountains and along the Qinghai-Tibet highway in the west and northwest of QTP were 1 order of magnitude lower than those from Lhasa and east Qinghai. The differences in soil OCPs among the sub-areas were 2-7 times. Soil PAHs were significantly correlated with emission density and soil organic carbon content (SOC), while OCPs were correlated significantly with the population density and SOC. Based on the calculated backward air mass trajectories and geographical distributions of emission and population, it was revealed that PAHs and OCPs accumulated in the soils in the west and northwest QTP were primarily from long-range transport and may represent the background levels of East Asia. This part of QTP can also serve as an important receptor area for regional or even global long-range transport study. The elevated concentrations of PAHs and OCPs in Lhasa and east Qinghai were mainly from local sources, while PAHs from adjacent Lanzhou area also contributed considerably to the accumulation of PAHs in east Qinghai.     

一起立式锅炉爆炸事故原因分析及隐患排查

采用现场勘察、光谱分析和金相检验等方法对一起立式锅炉爆炸事故进行原因分析,发现该锅炉制造时存在严重未焊透的设备缺陷和其他使用管理方面的问题。为此制定了超声波检测工艺,对本地区同一制造厂生产的在用锅炉进行隐患排查。对排查发现存在严重制造缺陷的锅炉进行现场维修或召回,对排查发现的使用管理方面的问题也一并跟踪整改。     

Source apportionment of polycyclic aromatic hydrocarbons in surface soil in Tianjin, China

Principal component analysis and multiple linear regression were applied to apportion sources of polycyclic aromatic hydrocarbons (PAHs) in surface soils of Tianjin, China based on the measured PAH concentrations of 188 surface soil samples. Four principal components were identified representing coal combustion, petroleum, coke oven plus biomass burning, and chemical industry discharge, respectively. The contributions of major sources were quantified as 41% from coal, 20% from petroleum, and 39% from coking and biomass, which are compatible with PAH emissions estimated based on fuel consumption and emission factors. When the study area was divided into three zones with distinctive differences in soil PAH concentration and profile, different source features were unveiled. For the industrialized Tanggu-Hangu zone, the major contributors were cooking (43%), coal (37%) and vehicle exhaust (20%). In rural area, however, in addition to the three main sources, biomass burning was also important (13%). In urban-suburban zone, incineration accounted for one fourth of the total.     

城市供水中藻类去除技术的研究进展

日趋严重的水体富营养化已成为全球性的环境问题,藻类及其副产物给传统净水工艺带来了诸多不利影响,增加了水处理难度。本文对饮用水中藻类各种去除技术进行了具体的论述,并系统分析各技术去除效果、局限性,展望了藻类去除技术发展前景。指出目前控制饮用水中藻类污染必须将水源污染综合治理、强化预氧化工艺、优化常规工艺结合起来。     

EGSB反应器处理含氯苯有机废水的试验研究

在间歇条件下,针对未接触和接触过氯苯的颗粒污泥,研究了氯苯对它们产甲烷活性的抑制及恢复;在动态条件下,研究了EGSB反应器处理含氯苯有机废水的情况.结果表明,不同浓度的氯苯均会对未接触氯苯的颗粒污泥的活性产生抑制;而接触过氯苯的颗粒污泥具有一定适应能力,只有氯苯浓度为100mg/L时才有较明显抑制.在动态运行过程中,进水氯苯浓度为10～50mg/L,前65天出水氯苯浓度均低于7mg/L,66d后出水氯苯浓度突增至25mg/L以上,停止投加氯苯后,出水氯苯浓度在3.4～38.32mg/L之间无规律波动,说明反应器内颗粒污泥对氯苯有较强吸附,生物降解作用不明显.     

牡丹江流域水质变化趋势及水环境污染特征研究

通过对牡丹江近10年水质监测、评价及变化趋势研究,采用单项污染指数评价法、环境功能区达标评价法,评价牡丹江丰水期、平水期、枯水期水质现状,给出超标项目与超标倍数,计算污染分担率、污染负荷比,绘制主要污染物各断面浓度变化图,总结牡丹江污染特点和水质变化趋势,得出牡丹江水环境污染特征,为环境管理提供科学依据。     

DELtatox便携式毒性测试仪在Q—TOX和B—TOX两种模式下应用与探讨

随着经济社会的发展,突发性水质污染事故日趋增多。因此能够快速、准确测定水质状况是环境应急监测的一项重要工作。在一起水厂取水口有人投药打鱼事故中,采用DELtatox便携式毒性测试仪在Q—TOX和B—TOX两种模式下快速检测事发地水质,结果表明快速、高效的检测为此次污染事故的成功处置提供了技术支持,为以后类似突发污染事故的应急监测提供了参考。