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.     

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.     

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。     

全氟辛烷磺酸盐(PFOS)替代品对中国白羽鹌鹑的生态毒性

为研究全氟辛烷磺酸盐(perfluorooctane sulfonate,PFOS)替代品对环境生物的毒害效应,选用中国白羽鹌鹑作为受试生物,建立其环境危害评价毒性测试方法,并对PFOS替代化学品进行了急性经口、急性饲喂及繁殖毒性的风险评价。结果表明,全氟丁基有机铵盐阳离子表面活性剂急性经口毒性实验的LD50为500.44mg·kg-1,其余3种替代化学品在上限浓度2000mg·kg-1,白羽鹌鹑均未出现明显死亡,4种PFOS替代品对中国白羽鹌鹑的急性经口毒性均为低毒。全氟丁基有机铵盐阳离子表面活性剂急性饲喂毒性实验的LC50为970.50mg.kg-1,对白羽鹌鹑的饲喂毒性为中毒,而其余3种替代化学品在上限浓度5000mg·kg-1,白羽鹌鹑均未出现明显死亡,对中国白羽鹌鹑的急性饲喂毒性为低毒。在长期饲喂过程中,织物三防整理剂和C6织物三防整理剂会表现出一定的生殖毒性,造成中国白羽鹌鹑的孵化率降低,胚胎死亡率及未受精率升高;全氟丁基有机铵盐阳离子表面活性剂会影响到中国白羽鹌鹑的未受精率,C4织物三防整理剂未表现出明显的生殖毒性。     

全氟辛烷磺酸盐(PFOS)替代品对中华蜜蜂的毒性

选用中国蜂种中华蜜蜂工蜂作为受试生物,建立其环境危害评价毒性测试方法,用所建立的方法对全氟辛烷磺酸盐(PFOS)替代品进行了接触急性毒性及经口急性毒性风险评价,并比较了"小烧杯法"和"饲喂管法"两种经口毒性方法的优缺点及对毒性结果的影响。研究结果表明,"小烧杯法"实验中C4织物三防整理剂对中华蜜蜂的24h-LC50为1435mg·L~(-1),48h-LC_(50)为284.67mg·L~(-1);其余替代品在限度实验均未出现蜜蜂死亡,4种PFOS替代品对中华蜜蜂的接触毒性及经口毒性均为低毒,但"小烧杯法"测得的经口毒性结果比"饲喂管法"高。     

全氟辛烷磺酸盐(PFOS)替代品对家蚕大造的生态毒性

以中国本地家蚕品种大造作为受试生物,实现实验室规模化饲料饲养和初步实验动物化;建立家蚕大造环境危害评价急性毒性测试方法;对4种PFOS替代品包括:50%的全氟丁基有机铵盐阳离子表面活性剂、用调聚法合成的织物三防整理剂(含固率23.7%)、用电解氟化法合成的C4和C6织物三防整理剂,进行了急性接触毒性、急性饲喂毒性及慢性饲喂毒性的安全风险评价。实验使用的4种PFOS替代品试验急性饲喂浓度均达到或超过2000mg·L-1,家蚕未出现明显死亡;在接触实验浓度达到10g·L-1时,家蚕未出现明显死亡,以上结果证明,4种PFOS替代品对大造蚕种的急性饲喂毒性和接触毒性均为低毒。较低浓度的表面活性剂会严重影响到大造蚕种的结茧率,当表面活性剂浓度为0.4g·kg-1时,蚕种不能结茧,其余3种化学品在浓度大于0.004g·kg-1,对大造蚕种的结茧率产生一定的影响作用,但抑制作用相对较为平缓。替代品均会降低家蚕茧层率,表面活性剂在浓度为0.04g·kg-1时,茧层率剧烈下降,其他3种替代品抑制作用相对平缓。织物三防整理剂、C4和C6织物三防整理剂几乎不会影响蚕卵孵化,但表面活性剂会造成家蚕孵化率降低,在0.04g·kg-1后孵化率为0。     

爬行动物应用于毒理学研究的现状

在系统介绍了爬行动物作为受试生物在毒理学研究中的应用现状基础上,总结了不同污染物对常见爬行动物个体和器官水平的毒害作用,重点综述了蜥蜴和龟毒理学研究进展。同时,论述了研究爬行动物毒理学的重要性,提出适合不同毒理学实验使用的爬行动物物种,并指出了爬行动物毒理学今后研究的重点及面临的难题。