Evidence-Based Framework to Manage Cyanobacteria and Cyanotoxins in Water and Sludge from Drinking Water Treatment Plants

Freshwater bodies and, consequently, drinking water treatment plants (DWTPs) sources are increasingly facing toxic cyanobacterial blooms. Even though conventional treatment processes including coagulation, flocculation, sedimentation, and filtration can control cyanobacteria and cell-bound cyanotoxins, these processes may encounter challenges such as inefficient removal of dissolved metabolites and cyanobacterial cell breakthrough. Furthermore, conventional treatment processes may lead to the accumulation of cyanobacteria cells and cyanotoxins in sludge. Pre-oxidation can enhance coagulation efficiency as it provides the first barrier against cyanobacteria and cyanotoxins and it decreases cell accumulation in DWTP sludge. This critical review aims to: (i) evaluate the state of the science of cyanobacteria and cyanotoxin management throughout DWTPs, as well as their associated sludge, and (ii) develop a decision framework to manage cyanobacteria and cyanotoxins in DWTPs and sludge. The review identified that lab-cultured-based pre-oxidation studies may not represent the real bloom pre-oxidation efficacy. Moreover, the application of a common exposure unit CT (residual concentration × contact time) provides a proper understanding of cyanobacteria pre-oxidation efficiency. Recently, reported challenges on cyanobacterial survival and growth in sludge alongside the cell lysis and cyanotoxin release raised health and technical concerns with regards to sludge storage and sludge supernatant recycling to the head of DWTPs. According to the review, oxidation has not been identified as a feasible option to handle cyanobacterial-laden sludge due to low cell and cyanotoxin removal efficacy. Based on the reviewed literature, a decision framework is proposed to manage cyanobacteria and cyanotoxins and their associated sludge in DWTPs.     

肝癌高发区饮用塘水浓缩物诱发人肝细胞非程序DNA合成的研究

利用人原代肝细胞非程序ＤＮＡ合成试验（ＵＤＳ）对广西某肝癌高发区的居民饮用塘水浓缩物进行检测，结果发现：塘水浓缩物的浓度在０．１０ｍｇ／ｍｌ－０．５０ｍｇ／ｍｌ时，可诱导人肝细胞ＵＤＳ反应，对ＤＮＡ具有明显的损伤作用，且显示出一定的剂量一效应关系，表明塘水中存在有基因毒性物质，提示该地区居民的肝癌高发与长期饮用糖水有关。     

Alterations in cerebral potentials evoked by rectal distention and drinking ice water in patients with irritable bowel syndrome

AIM: Visceral hypersensitivity has been found to be present in irritable bowel syndrome (IBS). The current study sought to study visceral afferent hypersensitivity in IBS patients and obtain further objective evidence of alterations in intestinal afferent pathways in IBS patients by cerebral evoked potentials (CEP). METHOD: We studied 30 female IBS patients and 12 female healthy subjects. Rectal perception thresholds to balloon distention were measured and CEP was recorded in response to rhythmic rectal distention (two distention series, each of 100 repetitions at a frequency of 1 Hz) at the volume of perception thresholds. All subjects were then asked to drink 220 mL 4 degrees C ice water and the above steps were repeated 20 min later. RESULTS: Rectal distention led to recognizable and reproducible CEP. Compared to healthy subjects, IBS patients demonstrated significantly shorter N1, P1 and N2 latencies (P < 0.05). After drinking ice water, IBS patients exhibited further shortened N1, P1 and N2 latencies (P < 0.05), but drinking did not alter the latencies of healthy controls and the amplitudes of both IBS patients and healthy controls. CONCLUSION: The shorter latency of cerebral potentials evoked by rectal distention and ice water stimulation in IBS patients provided further objective evidence for defective visceral afferent transmission in IBS patients.     

An evaluation of the relationship between 'atopic skin' and skin irritability in metalworker trainees

Skin hyperirritability to irritants as well as atopy are considered to be predisposing factors for contact dermatitis. The aim of the study was to evaluate whether these predictive factors are independent or whether they are so closely related that one could possibly replace the oilier. 205 metalworker trainees underwent skill examination for skin atopy, including standardised questionnaire, clinical examination of the skin and a series of skin irritability tests. These tests included measurements of transepidermal water loss (TEWL) before and after irritation with 3 different irritants: sodium lauryl sulfate (SLS), dimethylsulfoxide (DMSO) and sodium hydroxide (NaOH). The results of the linear regression analysis demonstrate that skin atopy is not associated with increased skin irritability, as assessed by the irritability testing methods presented.     

注射用水的工业化生产

本文讨论了注射用水生产工艺的发展和近代技术。介绍了纯水和注射用水的各种制造方法,包括蒸馏、反渗透、超滤、去离子法以及这些方法的组合工艺。并指出注射用水应该用去离子水经蒸馏制得。注射用水应贮放在附有空气过滤器的密闭贮罐内,水温应保持在80℃以上及处于循环回流状态,以确保蒸馏水的纯度及无热原。     

荆芥内酯平衡溶解度和油水分配系数的测定

目的:测定荆芥内酯的平衡溶解度和在正辛醇-水/缓冲液体系中的表观油水分配系数。方法:采用HPLC法测定荆芥内酯在水和各种有机溶剂中的平衡溶解度;采用摇瓶法测定荆芥内酯在正辛醇-水/缓冲液体系中的表观油水分配系数。结果:25℃时荆芥内酯在水中的平衡溶解度为910 mg.L-1,常用有机溶剂甲醇对荆芥内酯的溶解性较好,为93 855 mg.L-1;25℃时荆芥内酯的正辛醇-水的表观分配系数为49.35(lnKow=1.69)。结论:荆芥内酯在石油醚中几乎不溶,在水中的平衡溶解度较低,在甲醇中的平衡溶解度较高,在酸性至中性磷酸盐缓冲溶液中的表观分配系数变化不大,碱性条件下的表观分配系数明显下降。     

三起因二次供水引发的腹泻病暴发调查分析

[目的]分析N市三起介水腹泻病暴发的成因,探讨减少二次供水污染事故的对策。[方法]流行病学调查;检验饮用水微生物污染的程度及致病原;比较污染水(暴露组)和非污染水(对照组)供水范围内居民同期腹泻病发病率,计算相关危险度(RR)和归因危险度(AR)。[结果]腹泻病患者的住宅楼二次供水设施存在明显的卫生设计隐患,且日常性卫生管理松懈,蓄水池受到生活污水污染;发病居民饮用的受污染水感官指标异常、菌落总数分别为1.1×103、1.1×103、1.8×103 CFU／mL,总大肠菌群分别为1.6×104、1.6×104、＞230 MPN／L,检出豚鼠气单胞菌、河弧菌、温和气单胞菌、嗜水气单胞菌(菌量大于103CFU／mL),部分菌株检出耐热性肠毒素ST;三起介水腹泻病暴发的RR值分别为63.7、17.3、33.8,AR值分别为30.4、12.2、20.0。[结论]三起腹泻病暴发的主要原因与相关住宅楼二次供水严重污染有高度关联。     

2012—2013年岳阳市生活饮用水卫生状况调查

目的了解岳阳市2012—2013年各类生活饮用水的卫生状况及其影响因素,为保障居民饮用水水质安全提供科学依据。方法采用定期抽样的方法,每季度对岳阳市城区及周边县区的生活饮用水进行采样分析,按照《生活饮用水标准检验方法》中的规定进行采样检测,并依照《生活饮用水卫生标准》对结果进行评价。结果 2012—2013年共检测水样1 132份,其中出厂水186份,合格率94.1%;末梢水700份,合格率95.4%;农村学校内自建设施供水75份,合格率56.0%;城市二次供水171份,合格率96.5%。结论岳阳市生活饮用水整体达标情况较好,但农村学校自建供水水质不达标情况较多,不达标项目主要为总大肠菌群、大肠埃希菌、菌落总数等微生物指标,应引起相关部门的重视。     

Whole-body 3D water/fat resolved continuously moving table imaging

PURPOSE: To study the feasibility of three-dimensional (3D) whole-body, head-to-toe, water/fat resolved MRI, using continuously moving table imaging technology. MATERIALS AND METHODS: Experiments were performed on nine healthy volunteers, acquiring 3D whole-body head-to-toe data under continuous motion of the patient table. Two different approaches for water/fat separation have been studied. Results of a three-point chemical shift encoding and a spectral presaturation technique were compared with respect to image quality and performance. Furthermore, fast, low-resolution, whole-body water/fat imaging was performed in two minutes total scan time to derive patient-specific parameters such as the total water/fat ratio, the intraperitoneal/extraperitoneal fat ratio, and the body mass index (BMI). RESULTS: Good water/fat separation with decent image quality was obtained in all cases. The three-point chemical shift encoding approach was found to be more efficient with respect to signal-to-noise ratio (SNR) and acquisition time. CONCLUSION: Whole-body water/fat sensitive MRI using continuous table motion is feasible and could be of interest for clinical practice. Some improvements of the method are desirable.     

依达拉奉对老年痴呆大鼠学习记忆及海马4-羟基壬烯醛表达的影响

目的:探讨依达拉奉对老年痴呆大鼠学习记忆及海马组织丙二醛(malondialdehyde,MDA)及4-羟基壬烯醛(4-hydroxynonenal,HNE)表达的影响。方法:采用单次双侧脑室注射Aβ蛋白的方法制备老年痴呆大鼠模型,分依达拉奉治疗组(1次/d,3 mg/kg,皮下注射)、空白对照组和模型组。自手术前1 d起给药,第10 d,各组分别进行Morris水迷宫检测后,处死动物并取脑,生物化学方法测定大鼠海马组织MDA含量,免疫组织化学技术检测海马HNE表达。结果:模型组与对照组相比水迷宫实验潜伏期时间显著延长,目的象限停留时间百分比降低,前脑组织MDA含量增加,海马CA1区HNE表达增多。依达拉奉组较模型组水迷宫结果显著改善,前脑组织MDA含量减少,且海马CA1区HNE表达显著减少。结论:依达拉奉能提高老年痴呆大鼠的学习和记忆能力,这种作用可能通过降低MDA及HNE等自由基氧化损伤产物而得以实现。