重庆主城区空气降尘中重金属的特点及其在表层土壤中的累积量研究

探索不同功能区空气降尘中重金属通量特征并对其进行污染评价,对于了解空气降尘输入对土壤中重金属累积影响具有重要意义。对重庆主城的居住区(JZ)、文教区(WJ)、商业区(SY)、郊区(JQ)、交通区(JT)和工业-居住混合区(GJ)逐月进行空气降尘通量和Cr、Ni、Cd、Pb含量的测定。结果表明,工业–居住混合区的空气降尘通量平均值最高,文教区的最低。6类功能区秋季的降尘量相对较低。Cd、Cr、Ni和Pb的平均降尘量在不同功能区分布存在差异。空气降尘中4种重金属元素的平均含量为:Cd 2.14 mg/kg、Cr 66.36 mg/kg、Ni 27.69 mg/kg、Pb 98.33 mg/kg。6类功能区降尘中Cd、Cr、Ni和Pb 4种重金属含量一般冬季较高。地积累指数法的分析表明降尘中Cd污染最严重。经推算,以空气降尘的方式向土壤中输入的重金属,使重庆主城区土壤中Cd、Cr、Ni和Pb等4种重金属元素的浓度在累积100a后仍将低于《土壤环境质量标准》中的二级标准。土壤中重金属元素增加速度最快为Cd,其次为Pb和Cr,Ni的增长为负值。     

Using rainfall simulation and site measurements to predict annual interrill erodibility and phosphorus generation rates from unsealed forest roads: Validation against in-situ erosion measurements

The measurement of soil erosion rates under natural rainfall conditions is costly and time consuming. Data provided by rainfall simulation and static site measurements can be used to predict erosion rates under natural conditions, however the accuracy of this method is largely untested. This is especially true for erosion rates from unsealed forest roads. In this study, the values for a range of erodibility indices calculated from rainfall simulation experiments are compared to observed erodibility index values from 1 year of detailed in-situ erosion monitoring of seven different forest road types. The prediction of phosphorus generation rates from rainfall simulation and/or soil sampling was also evaluated. The results showed that a series of commonly used erodibility indices such as sediment per unit rainfall, sediment per unit runoff, sediment per unit EI₃₀, and sediment per unit rainfall energy were poorly predicted from the rainfall simulation experiments. Five of the six indices tested substantially overpredicted the observed erodibility at one site, a gravel road subjected to minimal traffic. For the other six road sites predictions were poor and highly variable, the coefficient of efficiency ranging from − 13.32 to 0.17 for these erodibility indices. A modified index, the ratio of sediment per unit rainfall energy to the mean rate of rainfall energy input, was able to predict annual erosion rates from six different road surfaces using rainfall simulation data with a coefficient of efficiency of 0.9. The results indicate that existing erodibility indices are not suitable for predicting observed erosion rates on forest roads using rainfall simulation data as collected in this study. It is argued that the modified index is more suited to sites (such as compacted roads) where interrill processes dominate, and erosion rates are less sensitive to peak flows. With respect to nutrient generation rates, rainfall simulation was able to accurately predict the observed proportion by mass of total phosphorus (TP) in runoff with a coefficient of efficiency of 0.96. Direct soil sampling of the road surface could also be used to predict the proportion by mass of TP in runoff. Concentrations of total nitrogen in forest road materials were found to be at the lower detection limit of the laboratory instruments.     

新疆奎屯垦区土壤砷污染现状评价

研究用网格布点法在奎屯垦区三个团场共采集土壤样品67个。通过对土壤中砷的测定,利用地统计学方法与GIS技术研究了该区域土壤(0～20cm)砷的污染状况,对土壤中砷的分布进行了探讨,并对砷在土壤中的含量进行了预测。结果表明:奎屯垦区土壤砷含量为10.31～33.99mgkg-1,平均值为20.21mgkg-1,高于全国平均水平(11.2mgkg-1);在所调查的67个土壤样点中有14个点超过了农田土壤环境的二级指标,超标率为20.90%,有29个点达到了警戒值;土壤砷含量大于25.00mgkg-1的区域主要在127团的东北部和西南部,128团的西北部和中部,在129团的西部和东南部也有零星分布。     

宝鸡市空气质量监测及数据分析

对宝鸡市环境空气监测国控点2003年的PM10、SO2和NOx监测数据进行统计分析,结合宝鸡市区污染调查资料及地形地貌,分析了污染物的变化规律及原因.结果表明,PM10为空气中首要污染物;PM10、SO2和NOx变化规律呈现典型的槽型分布,最大值出现在冬季12月份.     

固态畜禽废弃物利用现状及发展对策

阐述了畜禽废弃物对环境的污染和处理现状 ,针对存在的问题 ,提出了实现无害化、资源化和产业化利用的方法和途径。     

广州市畜牧业废水排放与治理现状分析

通过对广州市畜牧业废水排放总量、污染物排放强度、污染负荷和废水治理现状进行分析与评价,提出了防治畜牧业废水污染的对策和建议。     

农药对环境和人体危害的探讨

本文简述了农药对环境的污染及对人体健康的影响,并提出几点减轻危害的意见     

河北省农业生态环境劣势分析及其建设途径

河北省是环京津、环渤海的农业大省,由于人类活动的干扰,农业生态环境污染及生态系统退化问题日益突出,建设生态农业是改善农业生态环境的必由之路,为此必须注重农业原则与可操作性的统一,统筹规划,分类指导,抓好主导生态工程。     

中国水环境态势与方略

由于过去人类水资源利用的不合理,目前我国水环境已经恶化到极其严重的地步。文章系统地分析了我国水系、湖泊、海域的水环境状况,并针对我国实际污染情况提出了相应的防治措施     

河水氨污染急性死鱼模拟试验

为了查明河水中氨污染对常见淡水鱼类危害程度,设计本项模拟试验。经测定：水中氨氮含量＞ ４ ｍ ｇ／Ｌ时,淡水鱼就会出现急性中毒现象。不同种类、大小的淡水鱼对氨氮的忍耐度不同,呈一定规律。中毒症状主要表现为鳃部呼吸、血液循环障碍及体表应激反应