原料乳及其成品乳中重金属污染的研究

为了给消费者提供乳制品质量参考,对山东省某乳制品企业的原料乳和成品乳随机抽样,用原子吸收光谱法和原子荧光光谱法测定了其中铅、铬、汞和砷等重金属的含量．结果表明,该企业的原料乳和成品乳都存在不同程度的铅、铬、汞和砷等重金属污染,其中,部分原料乳铅含量严重超出国家食品质量安全标准,成品乳铅含量轻微超标．     

High arsenic tolerance in Brevundimonas aurantiaca PFAB1 from an arsenic-rich Indian hot spring

BackgroundArsenic contamination in the ground water of rural India is a recurrent problem and decontamination is mostly based on the chemical or physical treatments until now. Microbial bioremediation is eco-friendly, cheap, time-efficient and does not produce any toxic by-products.ResultIn the present study, a high arsenic tolerant bacteria Brevundimonas aurantiaca PFAB1 was isolated from Panifala hot spring located in West Bengal, India. Previously Panifala was also reported to be an arsenic-rich hot spring. B. aurantiaca PFAB1 exhibited both positive arsenic reductase and arsenite oxidase activity. It was tolerant to arsenite up to 90 mM and arsenate up to 310 mM. Electron microscopy has proved significant changes in cellular micromorphology and stalk appearance under the presence of arsenic in growth medium. Bioaccumulation of arsenic in As (III) treated cells were 0.01% of the total cell weight, while 0.43% in case of As (V) treatment.ConclusionsAll experimental lines of evidence prove the uptake/accumulation of arsenic within the bacterial cell. All these features will help in the exploitation of B. aurantiaca PFAB1 as a potent biological weapon to fight arsenic toxicity in the near future.How to cite: Banerjee A, Sarkar S, Gorai S, et al. High arsenic tolerance in Brevundimonas aurantiaca PFAB1 from an arsenic-rich Indian hot spring. Electron J Biotechnol 2021:52. https://doi.org/10.1016/j.ejbt.2021.05.006     

Study on arsenic level in ground water of Delhi using hydride generator accessory coupled with atomic absorption spectrophotometer

Surveillance of drinking water is essentially a health measure intended to protect the public from water borne diseases. Hydride generator accessory coupled with atomic absorption spectrophotometer was used to analyze arsenic level in 49 ground water samples collected from different areas of Delhi. Arsenic level in ground water samples was in the range of 0.0170 to 0.100 ppm (Mean-0.0431, Standard Deviation-0.0136, Std. error of Mean-0.00194) with minimum concentration at Raney Well No. 7 (0.0170 ppm) and maximum at Kotla Mubarak Pur (0.100 ppm). Arsenic containing sediments and percolation of chemicals into soil as the result of dumping of garbage rich in chemicals into open landfills could be the possible source of arsenic in ground water of Delhi. Extensive survey and continuous monitoring is required to be made to assess the magnitude of problem and earlier intervention.     

石膏和煅石膏中砷含量的测定

目的 :研究石膏和煅石膏中的砷含量。方法 :用DDC -Ag方法在 5 2 7nm处测定砷含量。结果 :市售石膏的砷含量超过了《药典》规定限量 ,煅石膏中未检出砷。结论 :砷含量的检测为评估石膏质量提供了依据。     

Effect of Arsenic Contaminated Drinking Water on Human Chromosome: A Case Study

Arsenic contamination of ground water has become a serious problem all over the world. Large number of people from Uttar Pradesh, Bihar and West Bengal of India are suffering due to consumption of arsenic contaminated drinking water. Study was carried out on 30 individuals residing in Ballia District, UP where the maximum concentration of arsenic was observed around 0.37 ppm in drinking water. Blood samples were collected from them to find out the problem related with arsenic. Cytogenetic study of the blood samples indicates that out of 30, two persons developed Klinefelter syndrome.     

以最小二乘法直线度评定食品中砷测定的不确定度分析

目的:以最小二乘法直线度评定食品中砷测定过程中存在的不确定度,并找出影响不确定度的因素较大的环节。方法:根据GB/T 5009.11-2003《食品中总砷及无机砷的测定》的方法,应用最小二乘法拟合直线,进行不确定度评估,并计算出合成不确定度。结果:各分量中工作曲线变动性、移液管、样品定容过程及测量重复性引入的不确定度贡献较大,相对扩展不确定度为U=2.5%(k=2)。结论:以最小二乘法直线度评定食品中砷的不确定度,提高了评定的可信度,通过实验各环节的分析,要求操作过程必须细心、准确、规范,尽量减少不确定度。     

Degradation of Emerald green in oil paint and its contribution to the rapid change in colour of the Descente des vaches (1834–1835) painted by Théodore Rousseau

Abstract

Descente des vaches (1836) by Théodore Rousseau in the Mesdag Collection in The Hague is barely readable and its paint layers are in poor condition. The surface of the painting is strongly deformed and cracked, the whole painting has darkened and especially the greens have lost all or most of their colour resulting in brown passages. Large passages of the painting that were painted with multiple thick and medium-rich layers have darkened dramatically. This paper proposes that the degradation of Emerald green (Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂, copperacetoarsenite) – the main green pigment used in this painting – is a significant factor in the cause of the darkening. Electron backscatter images reveal that the Emerald green particles are shown different degrees of degradation: from partially to completely disintegrated. Elemental maps show that arsenic is distributed throughout the paint cross section, with relatively higher concentrations around iron- and aluminium-containing particles, and in the varnish layer. Imaging-Fourier-transform infrared microscopy detects copper soaps in the degraded Emerald green-containing layers. Analytical data from four paint cross sections strongly suggest that Emerald green reacts with free fatty acids derived from the binding medium forming copper soaps and mobile arsenic-based species. Chemical laboratory experiments fully support this hypothesis. Emerald green and palmitic acid in chloroform form copper palmitate and arsenic trioxide (arsenolite, cubic) under room temperature and normal light conditions. The degradation of Emerald green particles in Descente des vaches has resulted in a loss of light-reflecting surfaces and in newly formed compounds in the paint, both contribute to the colour change from green to brown.     

流动注射氢化物发生原子吸收光谱法测油酸钠中砷的含量

建立一种油酸钠中微量砷的测量方法。方法:用氢化物-原子吸收分光光度法,在砷的特征谱线193.70nm用标准加入法测定油酸钠中砷的含量。线性回归方程为C=43.9445A-1.0075,R=0.99908。线性范围为0.5-6ng·mL-1,检测限是0.309ng·mL-1,油酸钠的回收率为94.3%～105.2%,相对标准偏差为3.26%,结论:该法检测限低、灵敏度高,是一种非常有效的分析方法。     

三江源区砷氟超标人畜饮水处理技术研发

人畜饮用水中砷、氟、矿化度的超标,是影响三江源区饮水安全的因素之一。本文针对人畜饮水中砷、氟超标情况,引进F-Catch、As-Catch2高性能粒状吸附材料,进行技术开发,设计出JCD-砷(氟)吸附系统。这种吸附材料对氟、砷酸、亚砷酸具有很高的吸附能力,吸附能力是目前国内外砷、氟吸附剂吸附能力的6倍以上,能吸附大量0.01ppm以下低浓度的氟离子和砷酸、亚砷酸。将JCD-砷(氟)吸附系统与活性碳联用形成砷、氟水处理工艺流程,该工艺流程的处理能力可达到0.5m3/h,按照国家农村用水标准每人每天40L水,能够解决200人的安全饮用水,适合于农村人畜安全饮水的需求。并在项目区进行了试验示范,将含砷原水打入JCD-砷(氟)吸附系统,吸附系统中的功能材料As-Catch2与进水中的砷进行物化反应。再通过JCD-砷(氟)吸附系统中的As-Catch2层下方的30cm高度的多孔质活性炭滤层,利用活性炭具有的高效吸附作用,吸附水中的微污染物质,最终出水进入集水箱中,通过泵打入居民生活用水管道,进入用户家中得以安全使用。设备处理速率快、时间短,无需进行预处理,实现了砷、氟、磷等指标的同时去除,砷去除率达到100%,氟去除率达到85%以上,处理后的水质满足国家生活饮用水卫生标准,且系统不产生污泥,节省了污泥处理费用,设备结构简单、具有灵活的可变性、成本较低,自动化程度高、操作简单、易于管理,为三江源区人畜安全饮水提供了技术保障。     

甘肃马鬃山玉矿遗址出土砷铜的科学分析

马鬃山玉矿遗址是西北地区目前发现的规模最大的早期工业遗存,出土有较多铜器。对其中4件具有西北地区特色的砷铜进行分析发现：1件为铜铅砷合金,1件为铜锡砷合金,2件为铜砷锑合金。马鬃山玉矿遗址出土铜器在材质上所展现出来的多样性,反映了该遗址与周邻地区文化之间存在着广泛的联系或互动。