餐厨垃圾国家政策及地方法规研究和思考

文章介绍了餐厨垃圾的产生和危害,以及目前国家及地方在餐厨垃圾处理方面颁布和制定的指导性文件、政策性法规、及行业标准。通过总结苏州、宁波、西宁、乌鲁木齐等城市在治理餐厨垃圾过程中的经验,结合这些地区在餐厨垃圾处理方面的地方法规、收集运输系统、无害化处理体系的建立过程,通过分析思考,提出了适用于一般城市的关于餐厨垃圾收集、运输、处理过程系统性的工作框架。指出了餐厨垃圾处理目前面临的主要问题,并对未来如何推进和完善餐厨垃圾处理工作提出了合理化建议,对政府未来的决策具有一定程度的参考意义。     

一次环境污染司法鉴定的测试与分析

受人民法院的委托,环境监测部门对一起汽车尾气致人死亡案件的现场进行大气污染物和空气质量的模拟测试。测试表明,在密闭的车库内,汽车外和汽车内CO浓度都会迅速增加,达到致人死亡的浓度,O2浓度迅速减少,最终使汽车发动机熄火。测试为司法部门提供案件审理现场空气质量数据,也提醒人们不要在密闭的车库内开启汽车空调取暖或纳凉休息。     

县级城市人居环境主客观指标体系与评价模型对比研究

本文对人居环境相关研究进行了阐述,并就城市人居环境指标体系与评价模型进行了分析研究。提出了人居环境质量主客观评价结合模型,其中指标体系包括四个一级指标和18个单项指标,并依据我国黄河三角洲高效经济区内14个县级城市2007年的调查统计资料,对人居环境客观建设水平和居民满意度进行了对比评价。运用因子分析法处理指标数据,问卷调查的方法进行满意度评价。评价结果科学可行,并揭示出影响县级城市人居环境的根本因素。     

土地利用总体规划环境影响评价技术方法的研究

从国内外土地利用总体规划环境影响评价的技术方法研究出发,总结了各技术方法的优势和缺点。最后提出了完善土地利用总体规划环境影响技术方法的建议。     

高温状态下受热时间对膨润土物性指标的影响∗

高温状态下膨润土的物性指标变化是高放核废物深地质处置库设计的重要参数之一。通过高温状态下不同受热时间MX80钠基膨润土的比重、液塑限、自由膨胀率试验,研究了受热时间对膨润土基本物性指标的影响规律;并通过热重分析(TGA)、X衍射(XDR)、电镜扫描(SEM)试验,从微观角度对上述变化规律进行了合理解释。研究结果表明:随着受热时间的增加,膨润土的比重、液塑限、自由膨胀率在受热15～30天内急剧下降,降幅分别为2.5%、3.1%和28.3%,之后各值变化量很小;高温状态下,膨润土的矿物成分转化、结合水脱附、微观形貌改变是膨润土物性指标发生变化的根本原因,三者之间相互作用和彼此影响。     

条形荷载下三明治形加筋土挡墙的变形特性分析∗

为了研究条形荷载作用下三明治形混合填土方式对加筋土挡墙变形特性的影响,采用 FLAC3D建立了数值计算模型,分析了三明治形加筋土挡墙的黏土弹性模量 E1、砂土弹性模量 E2、砂土厚度 d、筋材长度 L 以及荷载距面板距离 D 对挡墙变形特性的影响。结果表明：相对于加筋黏土挡墙,三明治形加筋土挡墙变形大幅减小,减少其墙顶沉降约 32%,减少面板位移约 44%;其土压力分布规律为墙后水平土压力大体上随填土深度的增加而增大;适当增大黏土弹性模量有利于减小挡墙顶面差异沉降;砂土存在一个最优弹性模量,使得面板水平位移最小;三明治形加筋土挡墙存在一个最优砂土厚度,使得三明治加筋土挡墙工作性能最佳;当 L/H≥0.7 时,继续增加筋材长度或当 D/H≥0.3 时,继续增大荷载距面板距离对挡墙影响相对较小。     

软土地区高墩梁桥抗震支座选型及横向约束构造研究∗

为了研究软土地区地震作用下高墩先简支后桥面连续梁桥的支座选型及横桥向抗震约束问题,选取了普通板式橡胶支座、钢阻尼滑板支座、LNR 橡胶支座和 HDR 高阻尼支座四种支座类型,以软土地区某(4×30)m 跨径高墩先简支后桥面连续梁桥为例,进行了延性抗震体系和减隔震体系抗震设计对比以及设置挡块的横桥向抗震约束效果研究。结果表明：软土地区高墩先简支后桥面连续梁桥墩柱配筋率主要由 E1 地震作用下墩底截面偏心受压检算工况决定,采用减隔震体系并不能降低桥墩配筋率。通过对采用四种不同支座桥梁的内力、墩梁相对位移以及配筋率方面综合分析可知,软土地区高墩先简支后桥面连续梁桥的周期较长,这类桥梁抗震关键问题是防止落梁、减小墩顶位移。采用普通板式橡胶支座并合理的设计纵横向防落梁装置的延性抗震体系更适宜于软土地区高墩梁式桥,合理设计抗震挡块可以起到很好的横向约束作用,避免横向落梁的发生。     

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.     

Molecular characterization and developmental expression patterns of thyroid hormone receptors (TRs) and their responsiveness to TR agonist and antagonist in Rana nigromaculata

Considering some advantages of Rana nigromaculata as an experimental species, we propose that this species, like Xenopus laevis, could be used to assay thyroid hormone（TH） signaling disrupting actions. To validate the utilizability of R. nigromaculata, we investigated the responsiveness of R. nigromaculata to a TH receptor（TR） agonist（T3） and antagonist（amiodarone） by analyzing expression, based on characterizing TR cDNA and developmental expression patterns. With high levels of identity with the corresponding genes in X. laevis, both TRα and TRβ in R. nigromaculata exhibited roughly similar developmental expression patterns to those of X. laevis, in spite of some species-specific differences. Both TRα and TRβ expression had greater changes in the liver and intestine than in the tail and brain during metamorphosis. T3 exposure for 2 days induced more dramatic increases of TRβ expression in stage 27 than in stage34 tadpoles but not in stage 42 tadpoles, showing that the responsiveness of R. nigromaculata to TH decreased with development and disappeared at the onset of metamorphic climax.Corresponding to greater changes of TRβ expression in the liver and intestine than in the tail and brain during metamorphosis, the liver and intestine had higher responsiveness to exogenous T3 than the tail and brain. Amiodarone inhibited T3-induced TRβ expression. Our results show that R. nigromaculata can be used as a model species for assaying TH signaling disrupting actions by analyzing TRβ expression, and intestine tissues at stage 27 are ideal test materials due to high responsiveness and easy accessibility.     

Arbuscular mycorrhizal fungal phylogenetic groups differ in affecting host plants along heavy metal levels

Arbuscular mycorrhizal fungi（AMF） are important components of soil microbial communities,and play important role in plant growth. However, the effects of AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） and host plant functional groups（herbs vs. trees, and non-legumes vs. legumes） at three heavy metal levels. In the meta-analysis, we calculate the effect size（ln（RR）） by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels.Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment.