不同条件下高炉渣吸附水中无机磷的研究

高炉渣(BFS)是在冶炼生铁过程中产生的固体废弃物,开展高炉渣的资源化研究具有重要意义.为了对水淬高炉渣净化含磷污水的应用提供理论依据,采取等温吸附的实验方法,比较了不同水淬炉渣的吸附磷效果,研究了不同pH和不同温度下水淬炉渣吸附磷的特点,结果如下:利用Langmuir等温吸附方程炉渣吸附磷的过程进行拟合,其相关系数均能达到显著水平.炉渣的碱度越高,吸附磷的效果越好;炉渣对磷的吸附能力随溶液pH的增加而降低,且初始为酸性(pH=2、4)的溶液在吸附达到平衡后pH有所上升,而初始为碱性的溶液(pH=10、12)在吸附达到平衡后pH有所下降;炉渣对磷的吸附是一个自发放热过程.     

Non-microcystin producing Microcystis wesenbergii (Komárek) Komárek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kützing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komárek) Komárek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin.     

家用洗衣粉中磷对斜生栅藻生长的影响

以洗衣粉中的有机磷为磷源,通过室内模拟的方法研究在不同磷浓度的水体条件下斜生栅藻的生长情况,以及磷对斜生栅藻的生长是否有毒害作用.通过显微计数测定藻细胞数目来探讨洗衣粉中磷对斜生栅藻生长的影响;同时分析了洗衣粉中磷对斜生栅藻96 h生长期中光合色素的影响.结果表明,洗衣粉中的磷除了促进藻生长外,其浓度过低或过高都会抑制藻的生长.由实验结果可得,磷对藻生长的富营养化作用和毒性作用取决于磷浓度的高低.     

三峡库区大宁河流域非点源污染研究

以大宁河流域巫溪水文站控制流域为研究对象,应用分布式非点源污染模型SWAT,利用实测流量、泥沙负荷及氮、磷负荷数据对模型进行了率定和验证,并模拟了大宁河流域的径流量和营养物质氮、磷的排放.结果表明,月平均流量在率定期和验证期的效率系数分别达到了0.93和0.62;泥沙负荷的效率系数分别为0.70和0.34;氨氮和总磷的效率系数分别达到了0.31和0.37.大宁河流域污染物质的排放存在着较大的空间差异,有机氮和有机磷的5年平均排放量区间分别为2.01～38.15和0.35～5.89 ks/(hm2·a),其中,流域西南部子流域的有机氮和有机磷平均排放量最大,分别为38.15和5.89 ks/(hm2·a),是大宁河流域污染物排放的最敏感区域.     

Fe0/厌氧微生物联合体系处理2,4,6-三氯酚影响因素的研究

利用Fe⁰/厌氧微生物联合体系对2,4,6-三氯酚(2,4,6-TCP)进行降解研究。结果表明,Fe0/厌氧微生物联合体系可以有效降解2,4,6-TCP,Fe⁰与厌氧微生物之间存在明显的协同效应。Fe⁰/厌氧微生物联合体系处理2,4,6-TCP的最优条件为：微生物接种量0.434 g VSS/L,Fe⁰投加量15 g/L,体系初始pH值7.0～8.0。     

有毒气体危害区域划分之临界浓度标准研究

通过研究毒物伤害准则进而界定有毒气体危害浓度,对有毒气体泄漏扩散后的危害区域进行分级划分,以采取相应的防护措施,最大限度的即时有效的减轻有毒气体对人员的伤害.最后,以氯为例,对比其在不同伤害准则下危害区域划分临界浓度标准值,数值差别较大,因此在使用时应根据实际情况加以判断,选择最适当的标准来划分危害区域.     

Short-term effects of gaseous pollutants on cause-specific mortality in Wuhan, China

In Asia, limited studies have been published on the association between daily mortality and gaseous pollutants of nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2). Our previous studies in Wuhan, China, demonstrated long-term air pollution effects. However, no study has been conducted to determine mortality effects of air pollution in this region. This study was to determine the acute mortality effects of the gaseous pollutants in Wuhan, a city with 7.5 million permanent residents during the period from 2000 to 2004. There are approximately 4.5 million residents in Wuhan who live in the city's core area of 201 km2, where air pollution levels are highest, and pollution ranges are wider than the majority of the cities in the published literature. We used the generalized additive model to analyze pollution, mortality, and covariate data. We found consistent NO2 effects on mortality with the strongest effects on the same day. Every 10-microg/m3 increase in NO2 daily concentration on the same day was associated with an increase in nonaccidental (1.43%; 95% confidence interval [CI]: 0.87-1.99%), cardiovascular (1.65%; 95% CI: 0.87-2.45%), stroke (1.49%; 95% CI: 0.56-2.43%), cardiac (1.77%; 95% CI: 0.44-3.12%), respiratory (2.23%; 95% CI: 0.52-3.96%), and cardiopulmonary mortality (1.60%; 95% CI: 0.85-2.35%). These effects were stronger among the elderly than among the young. Formal examination of exposure-response curves suggests no-threshold linear relationships between daily mortality and NO2, where the NO2 concentrations ranged from 19.2 to 127.4 microg/m3. SO2 and O3 were not associated with daily mortality. The exposure-response relationships demonstrated heterogeneity, with some curves showing nonlinear relationships for SO2 and O3. We conclude that there is consistent evidence of acute effects of NO2 on mortality and suggest that a no-threshold linear relationship exists between NO2 and mortality.     

Characteristics and driving factors of marsh changes in Zhalong wetland of China

Zhalong National Nature Reserve in the northeast of China is a large wetland and a habitat of hundreds species of fauna and flora. The rare red-crowned crane is one kind of endangered birds in it. Recently, Zhalong wetland is shrinking and it encounters many problems including occasional fires, bad water quality, human activities, etc. In order to find out a proper way to protect and restore the wetland, this study, using a geographic information system, the global positioning system and remote sensing techniques, analyses the spatial characteristics of the changes in marsh landscape pattern and examines the driving factors for these changes. Data sources include 8 Landsat Thematic Mapper satellite images of Zhalong area in the period of 1986–2002 and the investigation information on site. Based on the analysis of changes of marsh area and annual precipitation during the 16 years, it is found that there is a close correlation between annual precipitation and marsh area. It means that climate is one of driving factors of marsh pattern changes. To understand influences of other kinds of land uses on marsh spatial distribution in Zhalong wetland, this paper analyses the relationship between marsh and different kinds of land uses, such as water surface, residential area, farmland, salina land and grass land, respectively. According to the patch analysis theory, a fragmental index and a fractal dimension of the marsh are calculated with perimeter-area method. The results indicate that the marsh pattern is affected by human activities significantly. In addition, the location alteration of marsh centroid point over the 16 years is studied. The movement trace of marsh centroid point is concerned with different hydrological situation in different areas of the wetland. In summary the characteristics of the marsh landscape pattern evolution during the 16 years are affected by multiple driving factors. The main driving factors are climate, human activities, distribution of other kinds of land uses and hydrological situation in different areas.     

Generalized models for prediction of pentachlorophenol dissipation dynamics in soils

Dissipation of pentachlorophenol (PCP) in soil was investigated and the chemical relationships with soil properties were addressed. The results indicate that the dissipation of extractable PCP residues can be described using first-order kinetics equations, with a half-dissipation time (T(1/2)) ranging from 6.5 to 173.3d. The sharply different patterns of PCP dissipation in different soils were closely related to soil properties. Correlations of stepwise regression equations obtained were significant at 0.01 probability level between soil parameters and extractable PCP residues (R(2)=0.974**) as well as T(1/2) values (R(2)=0.882**). Using pH together with organic carbon content (OC) and soil particle size distribution, the dissipation dynamics of PCP in soil could be accurately predicted.     

Eutrophication conditions and ecological status in typical bays of Lake Taihu in China

Sampling was conducted at three site groups, group E (in East Taihu Bay), G (in Gonghu Bay) and M (in Meiliang Bay) in Lake Taihu. TN and TP concentrations among site groups was in the increasing order of E < G < M. TP level at G sites is at the critical threshold for loss of submersed macrophytes. Mean values of DO and Transparence showed different trend, i.e., E > G > M. The mean phytoplankton fresh-weight biomass at M sites was 5.81 mg/l, higher than that at E sites (4.96 mg/l) and G sites (5.18 mg/l). Mean zooplankton fresh-weight biomass was in the decreasing order of M (6.4 mg/l) > G (4.9 mg/l) > E (2.7 mg/l). However, Rotifera density was in the sequence of E > G > M. Both zooplankton biomass and phytoplankton biomass increased with the rise of TN and TP concentrations. Relationships between zooplankton biomass and phytoplankton biomass showed that zooplankton played a limited role in the control of algae in eutrophic lakes. Nutrient availability is much more important than zooplankton grazing pressure in controlling phytoplankton growth in lakes. For most sites in Lake Taihu, reduction of nutrient loading, as well as macrophyte conservation, zappears to be especially important in maintaining high water quality and regulating lake biological structure, but for M sites, it’s urgent to control nutrient inputs rather than to restore macrophyte community.