Assessing the impact of air pollution sources in Hong Kong, a densely populated city

As the simple dispersion model tested is not sufficiently accurate to predict the SO2 concentration in complex terrain commonly encountered amongst high rise buildings in Hong Kong, and the lack of comprehensive local wind data at most sites prevents the use of more advanced dispersion model to assess the impact of major air pollutant sources, a receptor model approach is adopted for the apportionment of air pollution sources in Hong Kong. The preliminary results obtained are presented and discussed.     

50Hz低频环境磁场对细胞增殖的影响及其机理探讨

本文以细胞株LO2(人肝细胞)和CHL(中国仓鼠肺成纤维细胞)为研究对象，用50Hz正弦磁场以不同强度、不同时间作用于细胞。长时间作用后，2种细胞的增殖均受到抑制，但抑制程度与磁场作用量并非呈简单的线性关系；磁场短时间作用对细胞增殖无明显影响，但细胞膜的流动性变差，在磁场撤去后膜的流动性又有所恢复。这一现象说明，低频弱磁场引起宏观生物效应需要时间的积累。同时观察到磁场短时间作用导致的CHL细胞上表皮生长因子受体(EGFR)的聚集，这可能是低频弱磁场引起宏观生物效应的一种机制。     

宣化城区大气TSP浓度分布预测及控制措施

根据宣化区燃料消耗量和TSP直接排放量 ,统计出全区TSP排放总量。在明确了排放源参数和气象参数的前提下 ,利用ISCST3模型模拟预测TSP浓度空间分布。各受体点的TSP夏季平均浓度值有 2 0 6%超二级标准 ,冬季平均浓度值有 3 4 9%超二级标准。烈士陵园的污染状况明显好于区政府 ,而区政府则明显好于焦化厂 ,焦化厂的全年TSP月平均浓度均超二级标准。通过对TSP污染原因进行分析 ,针对宣化区的特殊情况提出了控制对策     

大气颗粒物上多环芳烃的识别和源解析的进展

本文对当前大气颗粒物上ＰＡＨｓ的识别和源解析的定量及定性和半定量的方法进行了综述，定性及半定量方法简便易行，但误差大；化学质量平衡法结果较准确具体，但ＰＡＨｓ会发生化学反应而降解，并且没有各种燃烧源较完整的ＰＡＨｓ成份谱，这已成为ＣＭＢ广泛推行的障碍；多元统计方法不考虑ＰＡＨｓ的降解，但要求数据量大，国内外的科学工作者用不同的方法和手段，使ＰＡＨｓ来源的识别和源解析工作有了一定进展。     

受体功能区结构与环境内分泌干扰效应生物差异的关系

环境中存在的多种内分泌干扰物能够与生物体内的天然激素受体选择性结合并产生多种生物效应,由于受体功能区三维结构的不同,其内分泌干扰活性存在着种间、种内、组织间等的种种差异,限制了不同物种间毒性效应的外推研究,增加了环境内分泌干扰物筛选和风险评价的难度.论文综述了基于受体介导的环境内分泌干扰物生物活性与相应受体选择性及受体功能区结构关系的研究进展,并利用分子模拟方法分析探讨了雌激素受体与部分化合物结合作用模式,讨论了目前存在的问题,对以后有关方面的研究提出了建议.     

基于生态供受体理论的全国水土保持重要区识别

科学评估土壤保持功能是生态保护红线划定的基础.依据生态供受体理论,针对土壤保持服务对应的水土流失这一生态问题,从水土流失的供体（水土流失量）、受体（人口密度）、辐射传输（距离水体距离）三个方面构建模型,分析土壤保持功能的重要性.结果表明全国潜在侵蚀量577.34×10¹⁰t/a,潜在土壤侵蚀随着坡度和降水量的增加而增加.土壤保持功能极重要区面积98.98×10⁴km²,主要分布在西南地区的无量山和哀牢山,黄土高原东部,东南地区的浙闽丘陵,东部地区的鲁中山区、鲁东半岛,以及辽东半岛.西南地区山高、谷深、坡陡、流急、地形稳定性差等因素造成水土流失严重,维持该地区的水土保持功能极为重要;西北地区的黄土高原土质疏松且多暴雨导致水土流失比较严重,维持该地区土壤保持功能非常重要.对比常用的生态保护功能模型,供受体理论模型除考虑自然影响因素之外,突出了人类活动的因素,对评估生态保护功能与水土保持生态风险更客观.依据供受体理论构建的土壤保持模型适用于土壤保持功能和土壤潜在侵蚀风险的评估,可作为评估生态系统安全和划定生态保护红线的重要依据.     

基于模糊聚类的PM_(2.5)拟合组分选择模型的研究

提出了一种新的PM2.5源成分谱拟合组分选择模型,在充分考虑拟合过程的物理意义的基础上,采用聚类正确率作为组分选择的依据.实验验证,该模型能够准确获取较好的拟合主组分,相比与经验选或者手动盲选所得拟合结果,我们提出的模型将成功拟合(误差范围在0~0.05之间)的比例由40%提升到83%.     

Determination of dioxin concentrations in fish and seafood samples using a highly sensitive reporter cell line, DR-EcoScreen cells

There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay. Interestingly, the bioanalytical equivalent (BEQ) values obtained from the DR-cell assay [<0.1 ∼ 5.4 pg BEQ g⁻¹ wet weight (ww)] were closely correlated with the toxicity equivalent (TEQ) values from conventional high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis (r² = 0.912), and the slope of regression line was 0.913. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (1.095, the reciprocal of 0.913) to approximate the TEQ values from the HRGC-HRMS analysis. Furthermore, we used this DR-cell assay to perform a prescreening test of PCDD/Fs and dl-PCBs in 16 fish and seafood samples purchased from a supermarket, revealing that a sample from the fatty flesh of a bluefin tuna exceeded 8 pg TEQ g⁻¹ ww (the European Union-tolerance limit). Taken together, these results suggest that the DR-cell assay might be applicable as a rapid and low-cost prescreening method to determine dioxin levels in fish and seafood samples.     

The constitutively active Ah receptor (CA-AhR) mouse as a model for dioxin exposure - effects in reproductive organs

The dioxin/aryl hydrocarbon receptor (AhR) mediates most toxic effects of dioxins. In utero/lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) impairs fetal/neonatal development and the developing male reproductive tract are among the most sensitive tissues. TCDD causes antiestrogenic responses in rodent mammary gland and uterus and in human breast cancer cell lines in the presence of estrogen. Also, more recently an estrogen-like effect of TCDD/AhR has been suggested in the absence of estrogen. A transgenic mouse expressing a constitutively active AhR (CA-AhR) was developed as a model mimicking a situation of constant exposure to AhR agonists. Male and female reproductive tissues of CA-AhR mice were characterized for some of the effects commonly seen after dioxin exposure. Sexually mature CA-AhR female mice showed decreased uterus weight, while an uterotrophic assay in immature CA-AhR mice resulted in increased uterus weight. In immature mice, both TCDD-exposure and CA-AhR increased the expression of the estrogen receptor target gene Cathepsin D. When co-treated with 17β-estradiol no increase in Cathepsin D levels occurred in either TCDD-exposed or CA-AhR mice. In sexually mature male CA-AhR mice the weights of testis and ventral prostate were decreased and the epididymal sperm reserve was reduced. The results of the present study are in accordance with previous studies on dioxin-exposed rodents in that an activated AhR (here CA-AhR) leads to antiestrogenic effects in the presence of estrogen, but to estrogenic effects in the absence of estrogen. These results suggest the CA-AhR mouse model as a useful tool for studies of continuous low activity of the AhR from early development, resembling the human exposure situation.