Groundwater quality under the influence of spent mushroom substrate weathering

Nitrate and other solutes resulting from field-weathering of spent mushroom substrate (SMS) percolate into underlying soils and may migrate to groundwater. A field trial was conducted to investigate the potential influences of SMS weathering on groundwater quality. Spent mushroom substrate was deposited at 90 and 150 cm pile depths over a Typic Hapludult and weathered for 2 years. Eight casing wells were installed around the SMS piles to monitor the quality changes of groundwater with a high seasonal water table of 760 cm below the surface. Although leachate solutes had moved more than 200 cm deep in soil from the surface, no significant changes of groundwater quality caused by SMS weathering were observed even one year after removal of the SMS piles (3 years total). The groundwater had pH, electrical conductivity (EC) and dissolved organic carbon (DOC) of 4.3-5.7, 0.2-0.3 dS m(-1) and 0.7-2.2 mg L(-1), respectively. The major inorganic ions were Mg(2+), Ca(2+), Na(+), Cl(-), SO(4)(2-) and NO(3)(-), with a concentration range of 2.5-68.3 mg L(-1). The results suggest that SMS leachate solutes migrated fairly slow in deep subsurface soils of the experimental field. Considering that leachate solutes may move several meters in soil through preferential flow channels, weathering of SMS in fields with a high seasonal groundwater table >or=5 m below the ground is recommended. Conservatively, SMS weathering should be conducted on compact surfaces and leachate be collected and reused as liquid fertilizers.     

4类噪声标准适用区最佳监测时间研究

以1年的实测数据为分析样本,分别采用误差理论分析及数理统计分析方法,在保证一定精确度前提下确定出反映4类标准适用区噪声水平的最佳监测时间。     

赤潮研究的现状与展望

赤潮已成为一种严重的海洋灾害 ,引起沿海国家和地区的重视 ,并成为研究的热点。文章从赤潮发生的机理、赤潮管理与减灾等方面论述了赤潮研究的现状 ,并提出今后研究的重点。     

Degradation of Pesticides on Plant Surfaces and its Prediction - A Case Study on Tea Plant

The degradative kinetics of pesticides on plant surface are characterized by an initial rapid degradation which follows a first-order kinetics, then transferred to a more slower degradative rate. The degradative process mainly consists of photodegradation, evaporation, rainfall elution and growth dilution. The influencing parameters of these processes were investigated by using the tea plant as a case study. The predictive model of the initial concentration, photodegradation rate constant, evaporation rate constant, rainfall elution rate, growth dilution rate and the total degradation rate was discussed and verified in four locations situated in the range of 25°-30°N latitude, and acceptable results were obtained.     

工作场所空气中硫酸雾（SO3）的分析

采用碘量法测定工作场所空气中的三氧化硫及硫酸雾，三氧化硫及硫酸雾经中性水吸收后与碘化钾和碘酸钾反应，析出的碘与淀粉指示剂作用产生蓝色，进行比色测定。     

Modeling photocatalytic destruction of the organic contaminants in continuous stir flow reactor

Thin-film technique is becoming an industry standard for the preparation of TiO₂-based photocatalyst for organic destruction. The catalyst provides several advantages over the conventional powder TiO₂ in the treatment of wastewater and groundwater. In this study, a continuous stir flow reactor model is developed capable of describing the photocatalytic process. The model incorporates the following fundamental mechanisms: adsorption, diffusion, liquid-film transfer, UV attenuation, and photocatalytic reaction. All of the simulation results indicate that there exists a highly nonlinear relation between each of these parameters and the destruction rate. Various incident light intensities also are incorporated to simulate the energy efficiency. The simulations illustrate that the photocatalytic model can be used to elucidate the effect of process variables. It is also possible to “custom-design” a catalyst for the treatment of a particular waste stream.     

Modeling the spatial pattern of farmland using GIS and multiple logistic regression: a case study of Maotiao River Basin, Guizhou Province, China

Land use change is an important topic in the field of global environmental change and sustainable development. Land use change modeling has attracted substantial attention because it helps researchers understand the mechanisms of land use change and assists regulatory bodies in formulating relevant policies. Maotiao River Basin is located in the province of Guizhou, China, which has a developed agricultural industry in the karst mountain areas. This paper selected biophysical and social–economic factors as independent variables, and constructed a multiple logistic regression of farmland spatial distribution probability by random sampling. Then, by using GIS technology and integrating the 2000 data, this study predicted the farmland spatial pattern. When the predicted map was compared with the actual farmland map for 2000, we noted that 71% of the simulation is in accordance with the 2000 farmland pattern. The result satisfactorily proves the reasonability and applicability of our model.     

地面水环境质量评价的有时序多目标决策方法

将有时序多目标决策方法应用于地面水环境质量优势的比较，介绍了决策方法的原理和评价步骤。实例分析表明该方法计算过程简便，分辨率高，排序结果与实际环境质量状况相符合。     

发光细菌法评价工业废水的毒性

用发光细菌测定法估算了两城市污水对河道水体污染的分担率，评价了工厂排放废水的毒性，并据此确定了污染源监督管理中应优先治理的工厂（车间）废水。     

地下水环境质量变化动态研究

以邢台市环境保护监测站１０年来的监测资料为依据，运用单因子比值法，环比发展速率外推法和直线回归法，对地下水环境质量现状及１０年的动态变化进行了分析，研究和评述，并对发展趋势做了预测性评价。