Alginate immobilized enrichment culture for atrazine degradation in soil and water system

An atrazine degrading enrichment culture, a consortium of bacteria of genus Bacillus along with Pseudomonas and Burkholderia, was immobilized in sodium alginate and was used to study atrazine degradation in mineral salts medium (MSM), soil and wastewater effluent. Sodium alginate immobilized consortium, when stored at room temperature (24 ± 5°C), was effective in degrading atrazine in MSM up to 90 days of storage. The survival of bacteria in alginate beads, based on colony formation unit (CFU) counts, suggested survival up to 90 days and population counts decreased to 1/5^th on 120 days. Comparison of atrazine degrading ability of the freely suspended enrichment culture and immobilized culture suggested that the immobilized culture took longer time for complete degradation of atrazine as a lag phase of 2 days was observed in the MSM inoculated with alginate immobilized culture. The free cells resulted in complete degradation of atrazine within 6 days, while immobilized cells took 10 days for 100% atrazine degradation. Further, immobilized cultures were able to degrade atrazine in soil and wastewater effluent. Alginate beads were stable and effective in degrading atrazine till 3rd transfer and disintegrated thereafter. The study suggested that immobilized enrichment culture, due to its better storage and application, can be used to degrade atrazine in soil water system.     

Influence of toxicity and dissipation of racemic fenoxaprop and its R-enantiomer in Scenedesmus obliquus suspension by cyclodextrins

Cyclodextrins (CDs), a class of cyclic oligosaccharide molecules containing a variety of chiral centre, are capable of recognizing enantiomeric molecules through the formation of inclusion complexes. In this work, we selected three types of CDs, β-CD and its two derivatives, randomly methylated β-CD (RAMEB) and hydroxypropyl β-CD (HP-β-CD), to evaluate effects on toxicity of racemic fenoxaprop (rac-FA) and its R-enantiomer (R-FA) to freshwater alga Scenedesmus obliquus (S. obliquus) and their dissipation in S. obliquus suspension with and without CDs addition, respectively, in an attempt to get more detail about enantioselective behavior of fenoxaprop acid (FA) in the environment, using CDs as a remediation agent for FA and formulation additive for fenoxaprop-p-ethyl (FE). The significant difference between rac-FA and R-FA was not observed in their acute toxicity to S. obliquus and dissipation in S. obliquus suspension. RAMEB had no effect on either toxicity of FA to S. obliquus or dissipation of FA in S. obliquus suspension, and it also didn't change the extent of enantioselectivity in toxicity of FA to S. obliquus. But the addition of a certain amount of β -CD and HP-β -CD reduced the toxicity of FA to S. obliquus and increased dissipation of FA in S. obliquus suspension, as well as changed the enantioselectivity in toxicity of FA to S. obliquus. The results indicated β-CD and HP-β-CD could be used as a promising agent for remediation of aquatic contamination produced by FA, and RAMEB might be used as potential formulation additives for FE, the parent compound of FA, as RAMEB didn't decrease activity of R-FA and might be environmentally safer than the conventional additives.     

Comparative hersistence of chlorpyrifos in a mineral soil after granular and drench applications

Abstract

Lorsban 15G (15% chlorpyrifos) at 1.6 and 2.2 g a.i./10 m row, and Lorsban 4E (40.7% chlorpyrifos) at 2.0 g a.i./10 m row were applied respectively to a silt loam soil as a band treatment at seeding and as a drench after seeding. The rate of disappearance of chlorpyrifos [Q,Q‐diethyl Q‐(3,5,6‐trichloro‐2‐pyridinyl) phosphorothioate] was relatively fast in the first 15 days but slowed down considerably thereafter regardless of the methods of application and application rates; and there was a statistically significant (p=0.05) linear relationship between the natural logarithm of chlopyrifos concentration and time. Based on the linear regression equations, the calculated pseudo‐first‐order rate constants were 0.041 day^‐1 and 0.044 day^‐1 respectively for the band treatments at 1.6 and 2.2 g a.i./10 m row; and 0.040 day^‐1 for the drench. The calculated half‐lives for all three treatments were similar and they ranged frcm 15.8 days to 17.3 days. The degradation product 3,5,6‐trichloro‐2‐pyridinol (TP) was detected in soil but not 3,5_/6‐trichloro‐2‐methoxypyridine (TMP). The concentration of TP increased steadily to a peak and declined thereafter. The highest mean concentration of TP was 2.21 ppm (dry wt) detected 29 days after band treatment at the high rate. After 90 days the concentration of TP decreased to 0.43 ppm (dry wt).     

矿产资源资产负债表编制技术框架初探

矿产资源资产负债表编制技术框架的探讨对于推进我国不可再生资源资产负债表编制技术的形成、指导我国不可再生资源的科学开发并落实自然资源资产离任审计制度有着明确的实际意义。本文在国际通用的环境与经济综合核算体系的基础上,探索性的提出了矿产资源资产负债表的编制技术框架(以下简称框架)。该框架以实现国家矿产资源资产摸底和官员环境绩效评估为目标,函括了矿产资源资产负债表的编制原则,资产负债表的会计主体、会计要素、相关交易和事项的具体指向,资产负债表的实物量账户和价值量账户的内容和归类,矿产资源资产负债表的具体编制流程,以及矿产资源资产负债表示意等内容。具体而言:首先,本框架指出了矿产资源核算应坚持复式记账原则和权责发生制原则;其次,框架明确了会计主体为矿产资源的所有者(即政府),会计要素中的资产指的是由政府辖区控制的矿产资源,负债指的是政府开采矿产资源过程中从生态系统中"借"的其他自然资源(比如水资源、能源资源等)和生态服务(清洁的空气、水循环、气候调节等),这是本框架区别于传统国民经济核算的核心所在;再次,框架确立了矿产资源开采涉及的六大相关交易和事项,并据此设立了五类实物量账户和三类价值量账户,其中特别构建了集"生态系统服务"、"环境污染"和"资源消耗"三位于一体的"生态成本"和"生态负债"账户;最后,框架根据矿产资源开采的六大相关交易和事项,以及明确的以资产、负债与所有者权益为区分的会计账户,具体展示了矿产资源资产负债表的具体编制流程,并形成了最终的资产负债表示意。除此之外,本框架还提供了如何将实物类账户价值化的方法,特别提出了可用资源租金的净现值方法测度没有直接市场价格的非生产性资产的当前价值。该框架虽然是以矿产资源为研究对象,但其基本思路和技术也适用于其他不可再生资源的资产负债表编制。     

GIS在矿产资源评价中的应用

在矿产资源评价领域中,GIS的应用受到广泛的关注。作为一种地理学领域的信息系统,综合其它地质勘探、物探、化学等多种方法进行分析、判断,对矿产资源进行全面评价。讨论了GIS在矿产资源评价应用中的进展、作用、思路与方法以及应用过程中的关键问题。     

奎屯-独山子石化区夏季和秋季PM2.5形貌及矿物组成

PM2.5是城市大气的主要污染物,对人体健康危害巨大。研究PM2.5的形貌特征及矿物组成有助于解析PM2.5的来源和贡献及评估PM2.5对人体健康的风险。利用高分辨率场发射扫描电镜(FESEM)和能谱(SEM-EDX)对以石化为支柱产业的奎屯-独山子石化区域生活区和工业区的夏季、秋季PM2.5的形貌和矿物类型进行了分析。结果表明,奎屯-独山子的PM2.5主要包括矿物颗粒(规则矿物、不规则矿物)、烟尘集合体、球形颗粒(燃煤飞灰和二次粒子)、其他颗粒(生物质、未知颗粒)等4种类型,其中矿物颗粒在数量上和体积上均占优势。夏季规则矿物颗粒较多。从元素组成分析看,夏季PM2.5有"富Si"、"富Al"、"富Fe"、"富Ca"、"富Cu"、"富Zn"等类型,秋季PM2.5有"富Si"、"富Ca"、"富Fe"、"富Zn"、"富Cu"、"富Ti"、"富Ba"等类型,2个季节均以"富Si"颗粒占优势,表明道路扬尘、燃油飞灰、燃煤飞灰、工业粉尘、机动车尾气尘、城市扬尘等污染源是奎屯-独山子石化区夏季和秋季大气污染的主要来源。     

进口含锌物料的表征和鉴别

采用X射线荧光光谱(XRF)、X射线衍射光谱(XRD)等分析手段,对4种进口疑似固体废物的含锌物料进行了表征。通过分析含锌物料的主要元素组成、物相组成和常规理化特征,结合外观特征,与含锌矿物、含锌产品及相关文献资料等进行比对,推导出含锌物料的产生来源。然后,参照我国《进口废物管理目录》得出鉴别结论。结果表明:4种含锌物料分别为锌矿、湿法冶炼锌浸出渣、热镀锌灰和固定CO2产物;后3种属于我国目前禁止进口的固体废物。     

新的资源-环境勘查一体化评价观及建议

从矿产资源勘查、评价阶段开始考虑矿山环境问题,是实现绿色矿业的基石之一。本文从矿产资源勘查角度,讨论在矿产资源勘查的不同阶段(区域矿产普查、远景区勘查到矿床勘探即详查),传统资源学家所必须考虑的环境问题及地质勘探过程中所获资料在矿床(山)环境评价中的作用。作者建议:①为适应我国新时期地质工作的需要,应适时启动资源-环境一体化方面的研究,在资源评价和勘查阶段考虑环境问题,从资源评价与勘查获得的大量资料中提取环境信息,不仅可帮助解决一些与资源有关的环境问题,而且可提高地质资料的利用率;②虽然资源学家理解矿床环境有关的地质作用,具有研究矿床环境的某些优势,但我们必须即时转变观念,不断更新知识,特别是环境科学、流行病学和生物科学方面的知识,才能真正实现角色转换。     

Inclusive education for children with disabilities in a refugee camp

Children in refugee camps, and particularly those with disabilities, face unique challenges in accessing education and are at high risk of being marginalised. Best practices suggest that main-streaming is the optimal strategy for serving students with disabilities. This study examines the extent to which mainstreaming in a refugee camp helps to promote children's prosocial behaviours, taking into account their emotional and behavioural problems. In Kakuma Refugee Camp, Kenya, researchers collected data from the parents of children currently enrolled in special needs education centres (n=65) and from those formerly enrolled at these facilities who transitioned to mainstream classrooms (n=81). Children in mainstream schools functioned better in terms of prosocial behaviours, but this relationship disappeared when factoring in children's emotional and behavioural difficulties. In the context of a refugee camp, mainstreaming alone is not likely to help children's psychosocial and educational functioning, which requires dedicated supports, appropriate facilities and infrastructure, and a dual focus on disability-specific and disability-inclusive initiatives.     

多孔矿物-聚磷酸铵对甲烷爆炸的协同抑制研究

为探究新型多孔矿物(MTS)-聚磷酸铵(APP)复合粉体对甲烷-空气预混气爆炸的抑制效果,采用20 L球形爆炸装置开展多孔矿物、APP及其复合粉体在不同组成、不同添加浓度条件下的甲烷爆炸抑制试验,并使用热分析仪研究其热解行为.研究结果表明:当粉体添加量为0.100 g/L,多孔矿物与APP质量组成比为1∶3时,复合粉体...