我国典型农区耕地承载畜禽容量对比分析

根据农田养分平衡理论,对我国南北两个县级区域山东禹城和湖南桃源的耕地承载畜禽容量和负载指数进行了对比分析。 基于农田N收支情景分析表明:当农田施用粪便N分别占到总投入N的30%、60%和100%时,山东禹城耕地承载畜禽容量分别为4.1、8.3和13.8 LU·hm^-2,相应负载指数分别是2.2、1.1和0.7,湖南桃源耕地承载畜禽容量分别是4.4、8.7和14.6 LU·hm^-2,相应负载指数分别是1.4、0.7和0.4;基于农田N收支的耕地畜禽容量呈现为禹城略低于桃源,负载指数呈现为禹城显著高于桃源。基于农田P收支情景分析表明:当农田施用粪便P₂O₅分别占总施入P₂O₅的30%、60%和100%时,山东禹城耕地承载畜禽容量分别为6.7、13.5和22.5 LU·hm^-2,相应的耕地畜禽承载指数分别是1.3、0.7和0.4,湖南桃源耕地承载畜禽容量分别是2.5、5.1和8.5 LU·hm^-2,相应的负载指数分别是2.4、1.2和0.7,基于农田P收支的耕地畜禽容量呈现为禹城显著高于桃源,负载指数为禹城低于桃源。可见,禹城基于农田N收支的耕地承载畜禽容量显著低于基于农田P收支的耕地承载畜禽容量,桃源正好与禹城相反。因此,今后在制定减少农田环境污染对策时,禹城应首先考虑农田N收支及粪便N的有效管理与利用;桃源则应首先考虑农田P收支及粪便P的有效管理与利用,并且因为区域内乡镇之间存在较大差异,还应在乡镇之间进行协调平衡。     

Structural effect on photocatalytic degradation of metallised azo dyes in aqueous TiO2 suspension

Three metallised azo dyes were investigated under TiO₂‐photocatalytic and photosensitised conditions in aqueous buffering solutions. The degradation follows apparent first‐order kinetics. The size and strength of intramolecular conjugation determine the light‐fastness of the investigated dyes. Compared with ¹O₂ produced in photosensitised process, the more powerful *OH radicals in TiCO₂ photocatalytic process are highly reactive towards the investigated azo dyes. And as a result, the TiO₂‐photocatalysis makes little less distinction in the degradation kinetic data of the azo dyes compared with the photosensitised degradation of them.     

双氯芬酸在水环境中光降解的初步研究

考察了在模拟太阳光照射下,双氯芬酸初始浓度、pH值、光强、温度、丙酮和双氧水对双氯芬酸光解的影响,并通过淬灭实验初步探讨了双氯芬酸光解.结果表明,双氯芬酸的光降解过程符合准一级动力学方程.光解速率随着双氯芬酸初始浓度的降低、光强的增强以及温度的升高而增大.当pH值从3变化到5时,反应速率常数变大;pH值从5变到8时,反应速率常数变小,再继续增大pH值,反应速率常数增大.水环境中存在的双氧水和丙酮对双氯芬酸的光解具有促进作用.最后,通过淬灭实验表明双氯芬酸的光解过程包括直接光解以及通过活性氧物种进行的自敏化光解.     

Characteristics of geological hazards in South China coastal areas and impact on regional sustainable development

Prevention and treatment of geological hazards is important for the sustainable development of human society. Surface geological hazards alone caused direct economic losses of ¥3.47 billion, with 768 deaths and 785 injuries in Guangdong Province, South China, from 1994 to 2005. The major factors causing geological hazards can be categorised into three types: geo-environmental, climatic-meteorological and human activity. Accompanied by rapid economic development and population growth, human activities can cause geological hazards that are as serious as those caused by natural factors. The authors propose some suggestions for prevention and treatment of geological hazards to achieve sustainable development on the Chinese coast.     

Higher sorption of arsenate versus arsenite on amorphous Al-oxide, effect of ligands

Arsenic pollution is currently a major health issue because As is toxic for human beings, animals, and plants. Knowledge of As mobility is therefore important to assess health risk. The sorption of arsenite and arsenate on metal oxides in the presence of various anionic ligands is closely linked to the mobility, bioavailability, and risk. It was reported that the sorption mechanisms and characteristics of arsenite and arsenate on Al-oxides were different from that on Fe-oxides. Previous work reports the sorption of arsenite and arsenate on Fe-oxides in the presence of ligands. Whereas there is few knowledge on the sorption of arsenite and arsenate by Al-oxides in the presence of ligands. Here, we studied the sorption of arsenite and arsenate on amorphous Al-oxide by batch experiments. We tested the effect of organic ligands: oxalate, malate, tartrate, citrate; and inorganic ligands: sulfate, phosphate, selenate, selenite. Results show that amorphous Al-oxide has more sorption affinity for arsenate than arsenite. The inhibition of As sorption by ligands at pH 6 is higher for arsenite than arsenate. For arsenite, the As sorption inhibition decreases in the order phosphate, citrate, malate, selenite, oxalate, tartrate, sulfate, and selenate. For arsenate, the As sorption inhibition decreases in the order phosphate, malate, citrate, selenite, tartrate, oxalate, sulfate, and selenate.     

水体沉积物质量基准研究现状

沉积物质量基准是对水质基准的补充,对水质管理具有重要意义。目前国际上沉积物质量基准计算方法有十几种。对各种方法的理论基础、数据需求、适用范围等方面进行了概述之后,综合分析了各种方法的理论基础。研究结果认为,应将建立沉积物质量基准的方法分为以生物效应数据为基础的生物效应数据库法和以相平衡分配原理为依据的相平衡分配法。而根据统计方法不同,生物效应数据库法又分为单值基准、双值基准和三轴图法。同时还对美国、加拿大、荷兰、英国、澳大利亚和新西兰的沉积物质量基准研究发展和应用概况进行了分析。结合我国实际情况认为,依赖于大量生物效应数据的生物效应数据库法,目前在我国的适用范围有限,只能用于推导少数几种污染物的基准值。相平衡分配法具有可靠的理论基础而且不需要大量的生物效应数据,具有很大的发展潜力。因此,对于目前沉积物质量基准研究处于初级阶段的我国,更适合使用相平衡分配法计算污染物沉积物质量基准。     

Fermentative hydrogen production from beet sugar factory wastewater treatment in a continuous stirred tank reactor using anaerobic mixed consortia

A low pH, ethanol-type fermentation process was evaluated for wastewater treatment and bio-hydrogen production from acidic beet sugar factory wastewater in a continuous stirred tank reactor (CSTR) with an effective volume of 9.6 L by anaerobic mixed cultures in this present study. After inoculating with aerobic activated sludge and operating at organic loading rate (OLR) of 12 kgCOD?m^-3·d^-1, HRT of 8h, and temperature of 35°C for 28 days, the CSTR achieved stable ethanol-type fermentation. When OLR was further increased to 18 kgCOD?m^-3·d^-1 on the 53rd day, ethanol-type fermentation dominant microflora was enhanced. The liquid fermentation products, including volatile fatty acids (VFAs) and ethanol, stabilized at 1493 mg·L^-1 in the bioreactor. Effluent pH, oxidation-reduction potential (ORP), and alkalinity ranged at 4.1–4.5, -250–(-290) mV, and 230–260 mgCaCO₃?L^-1. The specific hydrogen production rate of anaerobic activated sludge was 0.1 L?gMLVSS^-1·d^-1 and the COD removal efficiency was 45%. The experimental results showed that the CSTR system had good operation stability and microbial activity, which led to high substrate conversion rate and hydrogen production ability.     

2012年全球地震灾害概要

2012年是近百年来全球地震的轻灾年.根据本年度国内外地震灾害资料,总结出2012年全球地震灾害的主要数据和“双震”成灾、沿“地球脐带”的分布特征.     

白蚁肠道共生微生物多样性及其防治方法研究现状

白蚁是破坏性极大的世界性害虫.结合课题组多年来开展的科研工作,综述了白蚁肠道中内生菌分离和白蚁防治方法的研究现状.已从白蚁肠道内分离出原生动物、细菌、真菌和螺旋体等多种生物.白蚁肠道中存在的微生物对白蚁消化木质纤维素类食物有着重要的作用.白蚁防治方法主要为物理方法、化学方法和生物学方法.生物防治白蚁方法具有高效、低毒、无残留、无污染、价廉的特性.介绍了以从抗白蚁树木分离到的内生菌生物发酵合成的代谢产物作为杀白蚁生物药剂的生物防治方法,该方法优势明显,有可能成为未来白蚁防治剂研究的方向,为白蚁防治提供重要途径,具有广阔的应用前景.     

沉积物中2,2',4,4'-四溴联苯醚(BDE-47)在铜锈环棱螺体内的毒代动力学及其繁殖毒性

多溴联苯醚(PBDEs)是一种全球性的新型持久性有毒污染物,沉积物中高浓度的PBDEs是水生态系统的巨大风险源,2,2’,4,4’-四溴联苯醚(BDE-47)在PBDEs同系物中,目前分布最广,生物毒性最强。为评价沉积物中BDE-47向底栖动物体内转移的潜力及其对底栖动物的潜在繁殖毒性,将实验室培养的铜锈环棱螺(Bellamya aeruginosa)暴露于BDE-47加标沉积物中,研究了BDE-47在铜锈环棱螺体内的毒代动力学特性及其对铜锈环棱螺潜在繁殖力的影响。结果表明,铜锈环棱螺对沉积物中BDE-47吸收较快,代谢速度相对较慢,BDE-47在铜锈环棱螺体内具有较强的生物积累性。生物积累达理论平衡时,铜锈环棱螺体内BDE-47浓度为1440.67ng·g-1(以样品干质量计)。BDE-47在铜锈环棱螺体内的生物积累和生物净化过程较好地符合一级动力学模型,摄入速率常数、清除速率常数和生物-沉积物累积因子分别为0.10、0.038和2.75,生物半衰期为18d。铜锈环棱螺体内BDE-47达到90%稳定状态所需的理论时间约为60d。低浓度BDE-47(160ng·g-1)暴露对铜锈环棱螺的潜在繁殖力没有影响,但当浓度≥640ng·g-1时,铜锈环棱螺的繁殖力下降50%,这表明BDE-47对铜锈环棱螺具有繁殖毒性。铜锈环棱螺可作为指示沉积物中底栖生物长期暴露于BDE-47的良好检测模型。