Impact of Harvest Intensity on Long-Term Base Cation Budgets in Swedish Forest Soils

The effects of harvesting on the long-term mass balances of calcium (Ca), magnesium (Mg) and potassium (K) were evaluated on a regional level in Sweden. A new high-resolution weathering database was used together with estimates of total deposition, losses through harvest and leaching. Estimates were made for pine and spruce separately and for two harvesting intensity scenarios: stem harvesting and whole-tree harvesting. The mass balance calculations showed net losses of Ca and Mg in almost the whole country for both scenarios. The losses were smaller for pine than for spruce. The K balances were mainly positive for pine but negative for spruce. Leaching was a main factor in the mass balances, especially for Ca and Mg. Whole-tree harvesting in spruce forests led to substantially higher net losses of K and Ca than stem harvesting, according to the calculations. In the whole-tree harvesting scenario in spruce forests the estimated yearly net losses of Ca, Mg and K corresponded to at least 5%, 8% and 3% of the pools of exchangeable base cations, respectively, at 25% of the analysed sites. If losses of this magnitude continue the depletion of the pools of Ca, Mg and K may lead to very low base saturation of the soils, possibly accompanied by negative effects on soil fertility, runoff water quality, tree vitality and tree growth within a forest rotation in parts of Sweden. Avoiding whole-tree harvesting can improve the situation substantially for K, but the losses of Ca and Mg will still be significant.     

成人高校数学课程的改革

本文根据数学教学的现状,提出了三方面的改革,即教学思想的改革、教学内容体系的改革,教师管理体制的改革。构造了数学基础、教学建模、数学实验室的教学体系。     

中国能源煤化工基地循环经济发展研究

能源煤化工基地由煤矿开采、燃煤发电、煤化工和建材四大主导产业组成,各个主导产业之间的产品、原料、能量、废弃物在一定程度上可以在行业内部或基地内部循环利用,达到节能、降耗、低碳、绿色的目的。本文构建了能源煤化工基地的循环经济框架,并针对各主导行业提出了发展循环经济的途径。     

A National Assessment of the Potential Linkage between Soil,and Surface and Groundwater Concentrations of Phosphorus

A meta‐analysis of three national databases determined the potential linkage between soil and surface and groundwater enrichment with phosphorus (P). Soil P was enriched especially under dairying commensurate with an increase in cow numbers and the tonnage of P‐fertilizers sold. Median P concentrations were enriched in surface waters receiving runoff from industrial and dairy land uses, and in groundwater beneath dairying especially in those aquifers with gravel or sand lithology, irrespective of groundwater redox status. After geographically pairing surface and groundwater sites to maximize the chance of connectivity, a subset of sites dominated by aquifers with gravel and sand lithology showed increasing P concentrations with as little as 10 years data. These data raise the possibility that groundwater could contribute much P to surface water if: there is good connectivity between surface and groundwater, intensive land use occurs on soils prone to leaching, and leached‐P is not attenuated through aquifers. While strategies are available to mitigate P loss from intensive farming systems in the short‐term, factors such as enriched soils and slow groundwater may mean that despite their use, there will be a long‐term input (viz. legacy), that may sustain surface water P enrichment. To avoid poor surface water quality, management and planning may need to consider the connectivity and characteristics of P in soil‐groundwater‐surface water systems.     

准东煤电基地工业固体废物综合利用研究

准东煤电基地部署10座燃煤电厂,电厂的开发建设带动当地经济社会发展的同时,对周围生态、环境空气质量产生较大影响.通过对准东煤电基地固体废物调查研究,调查结果显示10个电源项目年产生粉煤灰194.76万t、炉渣24.95万t、石子煤16.15万t、脱硫石膏86.04万t.工业固体废物在灰场堆存占用大面积土地,造成极大的资源浪费.为提高准东煤电基地固体废物综合利用率,结合准东地区现有企业对此类固体废物的利用情况,从循环经济、固废管理等角度提出准东煤电基地工业固体废物污染防治对策.     

基于成土母质的矿产资源基地土壤重金属生态风险评价与来源解析

矿产资源基地具有资源经济与环境污染双重属性,阐明土壤重金属的空间分布特征、污染现状及其来源,有助于甄别“自然污染”和“人为污染”.以滦河流域滦平县红旗镇钒钛磁铁矿资源基地为研究对象,采用地累积指数、内梅罗指数和潜在生态风险指数评价土壤重金属污染特征,利用冗余分析(RDA)和正定矩阵因子分解法(PMF)解析土壤重金属污染来源.结果表明,矿产资源集中的中基性角闪岩类和片麻岩类变质岩母质的Cr、 Cu和Ni含量平均值是其他成土母质的1～2倍,Pb和As含量平均值低于其他母质区.河道冲洪积母质Hg含量平均值最高,Cd在中基性片麻岩类变质岩母质、酸性流纹质火山岩母质和河道冲洪积母质中含量平均值较高.土壤重金属地累积污染程度(I_geo)依次为：Cd>Cu>Pb>Ni>Zn>Cr>Hg>As.内梅罗综合污染指数(P_N)变化范围为0.61～18.99,样点中10.00%和8.08%分别达到中度、重度污染,内梅罗单因子指数(P_i)显示中基性角闪岩类和片麻岩类变质岩母岩区的Cu、 Cd、 Cr和Ni...     

靶场训练环境构设效果评估方法研究

目的 针对靶场基地化训练战场环境构设效果难以定量评估的实际情况,研究定量评估方法,开展效果评估,辅助支撑改进环境构设方案筹划与课目实施。方法 分析环境构设的内容,确定效果评估的对象,构建环境构设效果评估指标体系,采用层次分析法计算权重取值,采用专家打分法确定指标取值,最终得出效果评估值,并给出环境构设效果等级。结果 以某次基地化训练实践活动为例,通过以上方法评估战场环境构设活动效果,验证了该评估方法的可行性。结论 该评估方法实际可行,提供了环境构设效果定量评估的思路,对改进战场环境构设活动有较强的指导意义。     

长期土壤酸化模型(LTSAM)

以碱总量守恒为基础，以Ｕｌｒｉｃｈ缓冲范围为模型主要框架建立了兼能描述酸性与石灰性土壤长期酸化反应过程的动态模型．经与ＳＭＡＲＴ模型在理论设计和模拟结果两方面作对比之后，又利用新建模型以北京地区典型褐土为例进行了硫沉降与酸（Ｈ＋）沉降的对比计算．结果表明：（１）ＬＴＳＡＭ模型能够很好地反映土壤缓冲酸的主要机制．（２）模式运行即稳定又省时．（３）大气硫沉降不同于酸沉降．也就是说，硫沉降改变时，阳离子（尤其是主要离子）沉降量的变化应当加以考虑．     

典型废旧塑料再生基地周边农田土壤中PAHs污染特征及健康风险评价

为了解废旧塑料再生行业对周边农田土壤环境的影响，在莱州市废旧塑料再生基地内部及周边农田采集22个土壤样品，利用高效液相色谱法对样品中16种多环芳烃（PAHs）含量进行了检测，并对其污染特征及健康风险进行了分析.结果表明，基地周边农田土壤中16种PAHs总含量为60.50~303.48 μg·kg^-1，除?（Chr）、二苯并（a，h）蒽（DahA）外，其余组分的检出率均为100%.萘（Nap）、苊烯（Acy）、苊（Ace）为主要组分，分别占总量的49.57%、21.32%、14.95%.参考Maliszewska-Kordybach的土壤PAHs污染程度划分方法，仅有22.73%样品达到轻微污染且集中于基地内部.在空间分布上，基地内部农田土壤中PAHs含量显著高于外部，总体表现为距基地越远，农田土壤中PAHs含量越低.基地内部各采样点PAHs的构成具有相似性，主要以低环芳烃为主，占PAHs总量的89.56%以上，表明基地内部农田土壤有相对固定的PAHs来源.主成分分析法共提取到3个主成分，表明基地周边农田土壤中的PAHs主要与燃煤、生物质燃烧以及废旧塑料焚烧有关.健康风险评估表明，成人和儿童对PAHs的暴露风险主要通过呼吸途径，儿童的暴露剂量均高于成人，但非致癌及致癌风险水平均在可接受范围.     

香草醛类席夫碱的制备及其对水中碘的吸附研究

核废料中的放射性碘对环境的污染日趋严重,固定回收放射性碘对核能的可持续发展至关重要.本文通过醛胺缩合制备了两种席夫碱共价材料—3,5-二氨基苯甲酸缩合香草醛（SB-35）和4-氨基安替比林缩合香草醛（SB-4）,并采用傅里叶变换红外光谱仪（FT-IR）、热重分析仪（TGA/DSC）、X-射线粉末衍射仪（XRD）、场发射扫描电子显微镜（SEM）等对两种材料的结构和形貌分别进行了表征.结果表明,两种席夫碱材料对水中碘具有较好的吸附效果,吸附行为更符合Freundlich等温吸附模型,表明该吸附过程以多分子层吸附为主;由Langmuir等温吸附可知,在25℃时SB-35和SB-4的最大理论吸附量分别为1356.49 mg·g^-1和1680.08 mg·g^-1.吸附热力学结果表明,两种材料对水中碘的吸附是吸热反应且自发进行,升高温度有利于反应进行.