Characterization of environmental water samples using strontium and lead stable isotope compositions

A simple procedure using both cation and anion exchange chromatography has been applied in the study of lead and strontium isotope composition in rain and stream water samples from remote catchments in Scotland. Whereas the soil released strontium to stream waters, lead was removed from rain water and the concentrations in stream waters were very low. Highly precise analysis by thermal ionisation mass spectrometry proved necessary in the determination of strontium isotope composition. The ⁸⁷Sr/⁸⁶Sr ratio in rain water was close to that of marine strontium but the ratios in stream waters were constant and highly characteristic for the stream. In the case of the stream at the Sourhope site, the ratio (0.70798 ± 0.00005) was less than that in rain water and probably resulted from the weathering of one specific mineral. The results suggested that the ⁸⁷Sr/⁸⁶Sr ratios could be used as a stable isotope tracer of waters and to provide information on the weathering processes. Two major anthropogenic components of lead were identified in water samples. One had its origin in petrol additives whereas the other was probably of industrial origin. The low ²⁰⁶Pb/²⁰⁷Pb ratios observed in stream waters confirmed the lead as being of anthropogenic origin and the data suggested that there was a movement, albeit very small, of lead from the soil to waters.     

长春市南湖大气降尘长期演变规律

本文统计分析了１９８４－１９９３年长春市南湖大气降尘数据，探讨了冬季与夏季的代表月份以及１０年间的代表年份大气降尘长期演变规律。１０年间冬季降法量呈波浪式递减趋势；从统计来看，冬季１月份降尘最是夏季７朋份降尘量的２．３倍左右；同年度内冬季、春季大风时段的除尘量一般高于夏、秋季；冬季煤烟型大气污染已逐年在所改善，一些自然因素对大气除尘的影响逐渐突出。     

Organochlorine and organophosphorus pesticide residues in the Atoya river basin, Chinandega, Nicaragua

The hydrographic basin of the Atoya river, located in the Department of Chinandega, one of the main cotton producing regions in Nicaragua, is intensively contaminated by pesticides. Samples of river waters and sediments, as well as strategically selected wells have been analyzed to study variations in the concentrations of organochlorine and organophosphorus pesticide residues between the dry season (November-April) and the rainy season (May-June). Generally, higher concentrations of pesticides have been detected in the river waters and sediments in the dry season. DDT, DDD, DDE compounds and toxaphene are the most frequent organochlorine residues found in the water and sediment samples, while endrin, aldrin, dieldrin and lindane are mainly found in the waters of rivers and wells. Organophosphorus compounds were rarely detected. However, residues of ethion, methyl-parathion and ethyl-parathion were found in high concentrations in some river and well water samples. Generally, organochlorine compounds tend to accumulate in the fine grain-size fractions, rich in organic matter, except DDE, which concentrates basically in the coarse grain-size fractions.     

相对灰色关联度在城市污水处理工艺优选中的应用

通过对城市污水处理工艺评价指标的定量化处理,并根据奖优罚劣的原则对初始指标集进行[-1,1]区间线性规范化处理,确定理想最优方案(A )和理想最劣方案(A-),以此计算出各待选方案与它们的相关系数(ζ)。采用变异系数法计算各指标权重(ω),并计算各候选方案相对最优方案的灰色关联度,进而确定最佳方案。     

还原性物质对化学需氧量（COD）测定的影响及消除方法

文中论述了还原性物质Cl^-、NO2^-、Fe^2＋、S^2-、NH3、NH^4＋等离子对化学需氧量测定的影响，着重探讨了消除上述离子的方法及原理，从而得出消除氯离子干扰可用银柱法的结论，特别是高氯离子浓度（〉20000mg／D的水样，其效果更佳。NO2^-的干扰可通过加入氨基磺酸来消除。Fe^2＋，S^2-干扰可通过在水样中通入空气，使之氧化除去来加以消除。NH3或NH^4＋干扰的消除，可通过除去水中的氯离子或用低浓度的K2C2O7溶液测定来加以消除。     

浅议白云山酸雨现状与发展趋势

通过对广州白云山1994～2004年10年降水监测结果分析及其对白云山酸雨现状调查,分析酸雨产生的原因和发展趋势,并对控制和降低酸雨污染提出建议.     

元江干热河谷环境变迁与适应对策研究

元江是我国著名的干热区，当前的独特生态环境是由自然环境变化和人类活动作用共同影响而形成的。经过区域发展的纵向分析比较，不同时期的环境变化与适应对策都具有特异性，正确的社会行为适应、生产与技术适应是区域特色产业建设和可持续发展的重要保障。     

废水测流堰槽设计方案探讨

分别计算了一般情况和特殊情况时工厂废水的流量 ,以及各种型式堰槽的测流和排水能力。通过分析比较 ,确定上部全幅堰与下部侧收缩堰相结合的方式是废水测流堰槽的最佳设计方案。     

水陆交错带土壤氮素空间分异规律研究——以月亮泡水陆交错带为例

研究了氮素在水陆交错带的水平和垂直分异规律。结果表明表层土壤氮素水平分异显著高于下层（NH4^ －N除外）且随水分梯度分异；表层土壤各形态氮素含量基本上呈由近水体向高岗地带递减的分异趋势；但下层土壤氮素分异因形态不同而异，NO3^-－N含量由中间带向两侧递减，NH4^＋－N变异方向则与表层变异相反，K－N、OR－N与TN分异趋势相似且与表层变异一致；NO3^-－N因具有迁移性和易淋失性而使其空间分异最为显著；NH4^ －N较稳定，易被土壤胶体所吸附不易向下淋失，空间分异程度最小；K－N、OR－N与TN垂直分异趋势也具相似性；水陆交错带湿地土壤中的氮素含量与SOM和TP密切相关，而pH值对氮素分异的影响则不太显著。     

Monitoring and assessment of daily exposure of roadside workers to traffic noise levels in an Asian city: a case study of Bangkok streets

Four noise monitoring sites were strategically established to evaluate average noise level and audiometric assessment at various traffic zones of Bangkok Metropolitan Region (BMR). During the monitoring period, noise levels were found to be 72.8–83.0 dBA during day time and 59.5–74.5 dBA during night time. The finding also indicated that traffic noise levels depend on distance from roadside, diurnal variation and character of the traffic and street configuration. Audiometric measurement of 4000 persons was carried by four major hospitals in Bangkok to study the relationship between traffic noise exposure of groups of people working in the streets and hearing loss. Four different categories of occupational people, i.e., drivers, street vendors, traffic officers and dwellers were selected and were further classified into age groups (16–25, 26–35, 36–45 and 46–55 years old) to monitor the traffic noise induced hearing loss throughout their everyday lives. The control group was deliberately chosen to screen out the effects of traffic noise. According to the audiometric investigation, it was revealed that hearing capacity of the daily noise exposure groups living in the three urban sites (Yaowarat Road, Din Daeng Road and Ratchaprarop Road) were noticeably poorer than those who were living in suburban site (Phahonyothin Road). It was noted that the mean hearing threshold level (HTL) of the 16–25 years old groups were found to have better hearing capacity than those older adults of 46–55 years old. In particular the mean HTL dropped at the frequency of 4000 Hz. Among the occupational population who were living in the urban monitoring sites, the driver groups were found to have the highest risk of traffic noise induced hearing loss.