Effect of an industrial discharge on water quality and periphyton structure in a pampeam stream

Seasonal sampling was carried out at four sites on a pampeanstream that receives industrial effluent from two textile factories. To evaluate water quality, several physical and chemical parameters were examined and the periphyton growing oncattail (Typha latifolia L.) were analyzed.Water quality and periphyton structure differed significantlybetween sites upstream and downstream of the discharge. Differences in temperature and also in concentrations of phosphate, dissolved oxygen, and phaeopigment were detected. At the same time, changes in the dominant algae groups wereobserved. Downstream of the industrial discharge, the numberof Bacillariophyta decreased, while species of Cianophyta andEuglenophyta were more abundant. This abundance correlated withincreased phosphate and organic matter content and decreased oxygen concentration. Although this study did not detect a reduction in the number of species, similarity between stands decreased downstream of the industrial discharge. Changes incommunity structure were readily detected in this situation because the communities of the polluted and unpolluted zones were qualitatively different. Periphyton growing naturally on Typha latifolia is a useful indicator of the impact of waste waters on the biota and can also be used to evaluate water body recovery.     

Using environmental stressor information to predict the ecological status of Maryland non-tidal streams as measured by biological indicators

In Maryland, U.S., an interim framework has recentlybeen developed for using biologically based thresholds, or `biocriteria', to assess the health of nontidal streams statewide at watershed scales. The evaluation of impairment is based on indices of biological integrity from the Maryland Biological Stream Survey (MBSS). We applied logistic regression to quantify how the biotic integrity of streams at a local scale is affected by cumulative effects resulting from catchment land uses, point sources, and nearby transmission line rights-of-way. Indicators for land use were developed from the remote sensing National Land Cover Data and applied at different scales. We determined that the risk of local impairment in nontidal streams rapidly increases with increased urban land use in the catchment area. The average likelihood of failing biocriteria doubled with every 10% points increment in urban land, thus an increase in urban land use from 0 to 20% quadruples the risk of impairment. For the basins evaluated in this study, catchments with more than 40–50% urban land use had greater than 80% probability of failing biocriteria, on average. Inclusion of rights-of-way and point sources in the model did not significantly improve the fit for this data set, most likely because of their low numbers. The overall results indicate that our predictive modeling approach can help pinpoint stream ecosystems experiencing or vulnerable to degradation.     

Assessment of China's economic loss resulting from the degradation of agricultural land in the end of 20th century

Land degradation is a consequence stemming from both natural processes and social economic activities. On the bases of analyzing general situation of agricultural land degradation in China, the monetary estimating methods such as market value method and shadow engineering method were used to quantitatively assess the economic loss resulting from land deterioration. Results showed that the economic loss in 1999 was 326.8l billion RMB Yuan, which accounted for 4.1% of GDP in the same year of China. If taking five items namely farmland conversion, soil erosion, salinization, decline in reservoir functions, and siltation in waterways and, comparing with that in 1992, the percentage of economic loss to GDP has increased by 1.5 in the only 7 years.     

我国热带地区胶—茶—鸡农林复合系统物质循环研究

以海南省文昌市典型的胶—茶—鸡农林复合模式为研究对象 ,以单作胶园、胶茶间作园为对照 ,采用定量研究与定性分析相结合的方法 ,研究其物质循环规律。结果表明 ,胶—茶—鸡农林复合系统的氮、磷输入、输出量最大 ,系统外物质投入率比另两系统明显减少 ,系统内养分循环量增加 ,因此 ,该系统具有较合理的物质循环结构。     

浅议农业源和生活源对长桥海的影响

通过对蒙自下游长桥海水质状况和主要污染源农业源、生活源的分析,提出污染控制对策。     

Effects of atmospheric mercury pollution on terrestrial ecosystem in Chongqing, China

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洞庭湖区湿地资源可持续利用途径研究

湿地具有特殊的生态功能和社会经济价值。洞庭湖区湿地垦殖强度大,造成了生态环境严重退化的恶果。研究表明:控制人口总量,退田还湖,建立湿地自然保护区,大力发展避洪耐涝型湿地特色产业是保护和合理利用湿地资源的有效途径,且已取得了良好的社会、经济、生态效益。由此认为,如何协调好人口、资源与环境的关系是实现湿地资源可持续利用的战略目标。     

我国城市污泥中醚类和卤代烃类有机污染物的初步研究

应用GC／MS联机检测技术对我国大陆和香港共11个城市污泥中4种醚类和4种卤代烃类化合物进行分析。结果表明，醚类化合物的总含量在0－7．743mg/kg之间，以双（2－氯异丙基）醚为主，主要分布在兰州污泥和广州污泥中；卤代烃类化合物的总含量在0．007－3．237mg/kg之间，以六氯环戊二烯为主，主要分布在兰州污泥、佛山污泥和沙田（香港）污泥中。污泥中醚类和卤代烃类化合物的种类及其含量与污水来源、污水处理方式、污泥类型、化合物的结构和理化性质等因素有关。     

钢渣湿法脱硫试验研究

以某厂钢渣为吸收剂,以旋流板塔为吸收器,对湿法脱硫进行了试验研究。通过分析钢渣脱硫前后的化学成分变化,以及试验脱硫率随反应过程的变化,提出了钢渣湿法脱硫的反应机理。同时,试验研究了液气比、进气SO_2浓度、浆液浓度等主要参数对脱硫率的影响,以及加添加剂的效果。试验结果表明,通过合理的设计和适当的操作,可使钢渣湿法应用于中低脱硫率(50％～70％)的场合,以取得综合治理、以废治废的效果。     

Stipulation of the criteria for the construction of eco agricultural county in China

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