京津冀PM_(2.5)的主要影响因素及内在关系研究

大气污染物的源排放是形成灰霾天气的内因,气象条件是形成灰霾天气的外因。本研究通过构建PM_(2.5)浓度的两段式分布滞后模型,结合自然环境因素及经济因素对PM_(2.5)的影响因素进行了综合分析。在第一段模型中构建了PM_(2.5)和大气污染物排放量的分布滞后模型,第二段模型中构建了不同的大气污染源对大气污染物排放量的影响因素模型。大气污染物排放源主要包括工业源、生活源、机动车源、集中式污染治理设施源。在工业源中,工业废气重度污染行业是大气污染物排放主要的贡献者;在生活源中,燃煤消费量对大气污染物排放影响很大,这也是冬季供暖期间PM_(2.5)剧增的原因;在机动车源中,尽管黄标车的保有量仅占汽车保有量的10%左右,但却占据了颗粒物排放量的绝大部分。利用京津冀代表性城市PM_(2.5)日度数据研究得出平均气温、平均风速、日照时数、平均气压、降雨量、平均相对湿度、沙尘暴等因素对PM_(2.5)浓度的负向与正向作用。研究发现,大气污染物排放量对PM_(2.5)浓度具有聚集的滞后效应,当期大气污染物排放量、滞后一期、滞后两期、滞后三期大气污染物对PM_(2.5)浓度具有显著的正向作用,且影响依次递减。构建的大气污染物排放量的污染源影响因素模型揭示一个地区煤炭消费量、工业废气重度污染行业工业增加值、黄标车保有量对该地区大气污染物排放量具有显著影响。本研究对优化能源消费结构和产业结构,减少空气污染物排放提出了对策建议。     

Assessing the fate of radioactive nickel in cultivated soil cores

Parameters regarding fate of ⁶³Ni in the soil–plant system (soil: solution distribution coefficient, K_d and soil plant concentration ratio, CR) are mostly determined in controlled pot experiments or from simple models involving a limited set of soil parameters. However, as migration of pollutants in soil is strongly linked to the water migration, variation of soil structure in the field and seasonal variation of evapotranspiration will affect these two parameters. The aim of this work was to explore to what extent the downward transfer of ⁶³Ni and its uptake by plants from surface-contaminated undisturbed soil cores under cultivation can be explained by isotopic dilution of this radionuclide in the pool of stable Ni of soils. Undisturbed soil cores (50 cm × 50 cm) were sampled from a brown rendzina (Rendzic Leptosol), a colluvial brown soil (Fluvic Cambisol) and an acidic brown soil (Dystric Cambisol) using PVC lysimeter tubes (three lysimeters sampled per soil type). Each core was equipped with a leachate collector. Cores were placed in a greenhouse and maize (DEA, Pioneer^®) was sown. After 44 days, an irrigation was simulated at the core surfaces to supply 10 000 Bq ⁶³NiCl₂. Maize was harvested 135 days after ⁶³Ni input and radioactivity determined in both vegetal and water samples. Effective uptake of ⁶³Ni by maize was calculated for leaves and kernels. Water drainage and leaching of ⁶³Ni were monitored over the course of the experiment. Values of K_d in surface soil samples were calculated from measured parameters of isotopic exchange kinetics. Results confirmed that ⁶³Ni was strongly retained at the soil surface. Prediction of the ⁶³Ni downward transfer could not be reliably assessed using the K_d values, since the soil structure, which controls local water fluxes, also affected both water and Ni transport. In terms of ⁶³Ni plant uptake, the effective uptake in undisturbed soil cores is controlled by isotope dilution as previously shown at the pot experiment scale.     

Probabilistic distribution coefficients (Kds) in freshwater for radioisotopes of Ag,Am, Ba,Be, Ce,Co, Cs,I, Mn,Pu, Ra,Ru, Sb,Sr and Th – implications for uncertainty analysis of models simulating the transport of radionuclides in rivers

The objective of this study was to provide operational probability density functions (PDFs) for distribution coefficients (K_ds) in freshwater, representing the partition of radionuclides between the particulate and the dissolved phases respectively. Accordingly, the K_d variability should be considered in uncertainty analysis of transport and risk assessment models. The construction of PDFs for 8 elements (Ag, Am, Co, Cs, I, Mn, Pu and Sr) was established according to the procedure already tested in Durrieu et al. [2006. A weighted bootstrap method for the determination of probability density functions of freshwater distribution coefficients (K_ds) of Co, Cs, Sr and I radioisotopes. Chemosphere 65 (8), 1308–1320]: (i) construction of a comprehensive database where K_ds values obtained under various environments and parametric conditions were collected; (ii) scoring procedure to account for the ‘quality’ of each datapoint (according to several criteria such as the presentation of data (e.g. raw data vs mean with or without replicates), contact time, pH, solid-to-liquid ratio, expert judgement) in the construction of the PDF; (iii) weighted bootstrapping procedure to build the PDFs, in order to give more importance to the most relevant datapoints. Two types of PDFs were constructed: (i) non-conditional, usable when no knowledge about the site of concern is available; (ii) conditional PDFs corresponding to a limited range of parameters such as pH or contact time; conditional PDFs can thus be used when some parametric information is known on the site under study. For 7 other radionuclides (Ba, Be, Ce, Ra, Ru, Sb and Th), a simplified procedure was adopted because of the scarcity of data: only non-conditional PDFs were built, without incorporating a scoring procedure.     

莱州湾地区水资源问题与对策分析

分析了莱州湾地区水资源对气候波动的敏感性,旱涝频率及水资源污染等问题。主要结论有：水资源对气候波动很敏感,降水增加 １０％,全区水资源总量将增加 ２１％;降水减少 １０％,全区水资源总量将减少 ２８％。旱涝频繁, ３０ ａ中共发生等级在涝以上的雨涝１０次,等级在旱以上的干旱１４次。在气候偏旱时期,特大旱共发生４次,而在气候偏湿时期仅发生１次特大旱;在气候偏湿时期,大涝及特大涝共发生４次,而在气候偏旱时期仅发生特大涝１次。该区水资源已受到严重污染;尤其是在海水入浸区,水污染已造成严重危害。     

论湖南省水旱灾害的地理规律性

水旱灾害是湖南省最严重的自然灾害,本文依据数十年来的水旱灾情资料,运用自然地理学的理论,方法,从灾害类型以及其特点和时空尺度上揭示了湖南省水旱灾害的地理规律性,为防灾减灾决策提供科学依据。     

盐碱地区土壤对混凝土腐蚀规律和机理的研究

根据多年的试验研究成果及对土壤理化性质的分析结果,论述了内陆盐土对混凝土材料腐蚀的规律和机理,分析研究了各种钢筋混凝土材料在埋设初期混凝土强度增长的机理和在埋设后期混凝土强度降低的机理,为在盐碱地区进行基本建设时合理选材及防腐设计提供参考.     

Distribution patterns of octylphenol and nonylphenol in the aquatic system at Mai Po Marshes Nature Reserve, a subtropical estuarine wetland in Hong Kong

Spatial and temporal distribution of octylphenol （OP） and nonylphenol （NP） in Mai Po Marshes, a subtropical estuarine wetland in Hong Kong, were investigated. Surface water samples were collected every month from 11 sites during the period of September- December 2004. Concentrations of OP and NP ranged from 11.3 to 348 ng/L and from 29 to 2591 ng/L, respectively. The high levels of NP and OP were found in November and December than in September and October. The levels of OP and NP have no significant spatial differences except September. Total organic matter in the sediments appeared to be an important factor in controlling the fate of these compounds in the aquatic environment.     

珠江广州市区河段磷的迁移和分布的初步研究

研究了珠江广州市区河段黄沙－员村全程１３１００ｍ水域和底泥中不同形态磷的含量分布。并探讨磷在水体和底泥中的转移途径，为水污染的防治提供科学依据。     

石膏矿采空区上覆岩层冒落规律与危险性评价

为对上覆岩层冒落的危险性进行有效评价,在工程实勘的基础上,将石膏矿上覆岩层的自然冒落作为一个逐级发展的过程来处理,并根据普氏平衡拱理论对各级拱形作出2点假定,即冒落拱顶部弧线为抛物线,矿柱按θ角剥蚀。提出以临界松散系数K作为其危险性评价因子,并根据所建立的一般冒落拱模型,分别推导得到条带矿柱及间隔点柱区域关于K的计算公式。最后,将该评价因子用于工程实际,实现对邵东石膏矿采空区的危险性分级。该评价体系,即可对石膏矿地表塌陷作出有效预测,也可对石膏矿地表危险程度进行合理分级。     

Concentrations, distribution, and bioaccumulation of synthetic musks in the Haihe River of China

Seven typical synthetic musks (SMs) in the samples from the surface water, sediment and fish of the Haihe River were measured. The SM concentrations in the sediment and surface water of the Haihe River were significantly lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Along the flow direction, the SM concentrations in surface water and sediment tended to increase from the upstream to the downstream of Dagu Drainage River. The Bioaccumulation factors (BAFs) of galaxolide (HHCB) and tonalide (AHTN) were calculated at high levels in the muscles of crucian carp, common carp, and silver carp. Most of the biota-sediment accumulation factors (BSAFs) for HHCB and AHTN were higher than 1.7, suggesting magnification possibly exist in the musk bioaccumulations of the three fishes in the Haihe River. No significant differences in HHCB/AHTN ratios were observed among the water, fish, and sediment samples (p > 0.05). However, the HHCB/AHTN values in the Haihe River were much lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Compared with several typical persistent organic pollutants (POPs), the musk concentrations were higher or comparable in the Haihe River.