污水处理市场化改革与运营监管探析——以深圳市龙岗区为例

运营监管是污水处理市场化改革中的重要问题。文章在分析污水处理市场运营监管必要性的基础上,围绕监管制度建设问题,通过对深圳市龙岗区污水处理市场化进程、监管体系的建立和运营监管措施的实证分析,总结经验及不足,并从中得出建立健全污水处理市场化运营监管体制机制的相应思路和建议。     

用偏高岭石、铜矿尾砂、粉煤灰生产土聚水泥试验

以偏高岭石和固体废物铜矿尾砂、粉煤灰为基料,以氢氧化钠、水玻璃等作为激发剂,在室温条件下制备土聚水泥。通过正交试验,研究不同基料配比、激发剂、外加剂的不同加入量等因素对试条抗压强度的影响,并确定最优配方;同时通过SEM观察了土聚水泥的形貌并研究了土壤聚合的反应机理。结果表明:其最佳配方中铜矿尾砂、粉煤灰的质量比之和接近60%,7天抗压强度比标号为P.O42.5的水泥高5%;该土聚水泥呈层状结构,缝隙较小,结构紧密。     

A 50-year sedimentary record of heavy metals and their chemical speciations in the Shuangtaizi River estuary (China): implications for pollution and biodegradation

Two parallel sediment cores collected from tidal flat located in the Shuangtaizi River estuary were analyzed for heavy metal concentrations and chemical speciations. Based on the ¹³⁷Cs activity profile, mean sedimentation rate at the sampling site during the past 50 years was estimated to be 1.3 cm·a⁻¹. Correlation analyses show that almost all the metals are associated with each other, suggesting that these metals might be derived from same sources and/or affected by same geochemical processes. Influence of total organic carbon (TOC) content on the concentrations of Cr, Ni, Cu and Cd is evident. Silt and clay contents, instead of sand content, play an important role in the distribution of these metals. The dominant binding phases for most of the metals (except for Cd) are the residual. The relative decrease of the residual fraction of Cd and Pb in the upper 66 cm of the core is striking. The distribution of chemical fraction confirms that the residual fractions of these metals have a natural origin, while only the non-residual fractions of Cd and Pb increased upward the core due to pollution in the past five decades. Pollution assessment on these heavy metals based on Index of Geoaccumulation (I _geo) also demonstrates that most of the metals are unpolluted. The weak pollution as observed in the sediments is perhaps related to a local plant, the Suaeda heteroptera Kitag, which may have played a significant role in the biodegradation of these metals and the metal distribution in the estuary.     

内蒙古四子王旗2008及2009年沙尘天气研究

通过对四子王旗2008年和2009年3-5月份大气TSP浓度的测定,结合同期主要气象因子数据,依据国家规定的大气中TSP含量的标准和国家环境空气质量标准,对四子王旗的沙尘天气进行分类,并对其强度等级进行划分。评价结果表明：在2008年3-5月份中,发生了5次浮尘天气,2次扬沙天气,其中在2008年5月26日TSP浓度值为3.058mg/m3,达到扬沙天气等级。在2009年3-5月份,发生1次扬沙天气,TSP浓度值为3.369 mg/m3;四子王旗大气中TSP浓度含量符合国家环境空气质量二级标准;大气中TSP浓度与风速、环境温度呈正相关,与降雨量、大气压呈负相关。     

危险化学品储存企业的风险分析与应对措施

阐述了危险化学品储存企业存在和面临的风险种类,分析产生风险的原因,通过对风险因素的分析和评估,提出了缩减风险的应对措施,从而降低事故概率和频率,减少了危险化学品储存企业的风险。     

Cd2+、Pb2+在根际和非根际土壤中的吸附-解吸行为

采用1次平衡法对Cd²⁺、Pb²⁺在小麦根际和非根际土壤中的吸附-解吸行为进行比较研究.结果表明,根际土对Cd²⁺和Pb²⁺的吸附能力高于非根际土,2类土壤对Cd²⁺的吸附等温线与Freundlich方程有较好的拟合性,Pb²⁺的等温吸附过程可由Langmuir方程与Freundlich方程来描述.双常数方程是描述根际、非根际土Cd²⁺和Pb²⁺吸附动力学行为的最优模型,其次为Elovich方程,最差模型是一级动力学方程.Cd²⁺、Pb²⁺ 的解吸存在滞后现象,相比于非根际土,根际土吸附态Cd²⁺、Pb²⁺ 的解吸率更低,Cd²⁺、Pb²⁺的解吸量与其初始吸附量之间的关系符合2次幂方程.2类土壤Cd²⁺、Pb²⁺的解吸速率随重金属初始浓度的增加而增加,随解吸时间的延长而不断降低.描述根际和非根际土Cd²⁺、Pb²⁺的解吸动力学过程的最优模型均为双常数方程,其次为Elovich方程,一级动力学方程拟合效果不佳.     

利用连续GPS资料分析芦山7.0级地震区域地壳变形特征

2013年4月20日,龙门山断裂带南段四川芦山附近发生7.0级地震,造成较严重地震灾害及其次生灾害。为研究地震区域地壳变形特征,利用芦山地震震中周边陆态网GPS连续站2010-2013年的观测资料,得到发震区域水平运动速度场和垂直形变场,获得距震中较近站点的同震位移;利用站间基线时间序列和应变参数时间序列得到了区域应变积累背景,并结合块体运动信息分离方法,进一步分析了震前可能存在的异常形变信息。从中得知:芦山地震发震区域处于块体挤出的"分流"地带,地壳水平变形量较小。站间基线QHBM-SCSN和QHBM-SCXJ在2012年下半年均出现偏离原有运动速率的趋势。SCXJ站时间序列信息分离结果显示,其N向和E向应变贡献分量在2012年也有曲线转折现象。     

N-取代氟乙酰胺结构与急性毒性的CoMFA和CoMSIA研究

采用比较分子场分析(Co MFA)法和比较分子相似性分析(Co MSIA)法,对19种N-取代氟乙酰胺的小鼠急性毒性进行三维定量结构活性关系(3D-QSAR)的研究,模拟计算不同基团在立体场和静电场中对化合物急性毒性的影响,采用交叉验证相关系数(Q2)、非交叉验证相关系数(R2)表征模型的优劣。结果表明,Co MFA模型的交叉验证系数Q2为0.563,非交叉验证系数R2为0.992,优于二维构效关系,且其急性毒性主要由其立体场决定;单独采用立体场的Co MSIA模型预测能力最强,交叉验证系数Q2为0.767。在不同场组合的Co MSIA模型中,立体场和疏水场的贡献最大,而静电场的贡献最小。     

黑土微生物量和酶活性对邻苯二甲酸二丁酯污染的响应

邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)是一种在环境中广泛存在的有毒有机化合物,已被我国列为优先控制污染物之一。本研究探讨了不同浓度的DBP污染对黑土呼吸、微生物量以及黑土酶活性的影响。结果表明,DBP污染处理的黑土呼吸速率和微生物量碳较对照均显著增加;微生物氮在DBP污染过程中呈"降低-升高-降低"波动性变化;微生物磷与DBP污染浓度呈显著负相关;DBP对黑土多酚氧化酶表现为先促进后抑制,对转化酶和蛋白酶活性表现为低浓度促进而高浓度抑制;在DBP污染过程中脲酶呈现被激活状态;黑土过氧化氢酶和酸性磷酸酶均受到DBP污染的显著抑制。通过相关性分析发现,土壤微生物量、土壤酶活性与DBP污染浓度之间存在着高度的相关性。由此可推断,DBP污染改变了黑土呼吸、微生物量和酶学活性的代谢特征,进而有可能影响了黑土的生态系统功能,威胁到黑土的可持续利用。     

The Mass and Energy Exchange of a Tibetan Glacier: Distributed Modeling and Climate Sensitivity

Most glaciers in the Tibetan Plateau (TP) are not closely monitored for mass balance (MB) due to their inaccessibility, which makes it difficult to better understand the dynamics of glacial advancement or retreat. Surface energy budget, MB, and the resulting melt runoff were calculated for Zhadang glacier (5,710 m above sea level) of the central TP. Energy balance was calculated on 30‐m square grids for the summers of 2007 and 2008. On average, net radiation dominated the total energy source (66%) while the residual was supplied by sensible heat flux. More than 67% of the energy sink was available for melting on the glacier. Thus, less than 33% of the total energy was consumed by latent heat flux. A large and a slightly negative summer MB were calculated for the 2007 and 2008 summers, respectively. The high sensitivity of the glacier to air temperature may indicate that the lower than average seasonal temperature was more important than the increased precipitation for the slightly negative MB in the summer of 2008. Comparisons of glacial melt runoff indicated that rainfall and snowmelt were the dominant contribution to total runoff in the glacierized basin and the ice melting is also very important. Glacial melt calculation provides a basis for quantifying glacial melt‐runoff contribution to the river streamflow in the TP.