食物中亚硝酸盐清除方法研究进展

亚硝酸盐作为国家允许的食品添加剂广泛存在食物中,但其过量会对人体产生严重危害,为减少亚硝酸盐对人体的危害需对其进行深入研究.作者从物理、单一成分与食物提取液3个方面描述亚硝酸盐的清除方法,对亚硝酸盐的清除问题提出进一步的思考,为其清除问题提供新的课题,为百姓健康生活提供科学的应用研究.     

城市回用污水中病毒对人体健康风险的评价

目的评价城市回用污水中病毒对人体健康的风险。方法于2002年5～11月对西安北石桥污水净化中心二级处理出水和常规再生工艺处理后的回用水中的总大肠杆菌和粪大肠菌进行检测并进行数据的正态分布假设检验。同时观察了液氯消毒对污水中大肠杆菌的去除效果。利用评价饮用水中病原微生物感染概率的beta-Possion模型和MonteCarlo模拟方法对城市回用污水中病毒对人体健康的风险进行评价。结果二级处理出水和回用水中粪大肠菌群浓度呈对数正态分布。污水中大肠杆菌去除率在7mg/L和15mg/L液氯接触20min时分别为4log和5log。城市回用污水用于城市绿化和灌溉农田时,水中病毒对人体健康的年风险均值分别为1.21×10-6和4.31×10-8,且其最高风险均低于美国EPA地表水处理规范(SWTR)规定的生活饮用水可接受年风险(10-4),即使回用于对人体暴露量较大的景观娱乐用水(如游泳),其年风险值<10-4的概率也在90%以上。结论城市回用污水用于城市绿化和灌溉农用时,水中病毒对人体健康风险很小。     

清除废液管中液体的方法

为落实<医疗废物管理条例>,加强本市医疗卫生机构医疗废物收集、运送、贮存的管理,防止医疗废物污染环境、危害人体健康,我院自2003年5月开始用黄色塑料袋包装废弃液管统一回收,送北京市卫生局指定地点焚烧处理,交费3元/kg,我院每月产生医疗垃圾8000 kg,交费24000余元.     

污水污泥中微量元素提取方法的研究

本文研究了从污水污泥中提取微量元素Ｆｅ、Ｍｎ、Ｃｕ、Ｚｎ的实验方法，通过不同酸不同固液比对微量元素提取的影响研究，得到提取率高、成本低、便于开发应用的有效方法。     

清除眼睛内微尘的方法

在生产劳动中或在日常生活中，时常会遇到眼睛中落入微细灰尘的困扰，影响生产和日常生活，严重时会造成几天不能工作。     

血液透析机水处理系统及供水管道内毒素清除方法的研究

目的 探讨血液透析机水处理系统及供水管道内毒素清除方法的有效性,为预防因血液透析系统污染而引起的医院感染提供控制方法.方法 采用传统和改良方法对血液透析机水处理系统及供水管道消毒处理,在每次消毒后采集透析液、透析用水进行细菌内毒素限度检测.结果 单用传统方法经过氧乙酸或过氧化氧消毒处理后,内毒素清除率分别为33.3%和22.2%;采用改良后的多酶清洗液与含氯消毒剂协同洗消,内毒素清除率为100.0%,传统与改良方法清除内毒素效果差异有统计学意义(P＜0.01).结论 改良后的洗消处理方法能有效清除血液透析机水处理系统及供水管道内毒素的污染.     

辽宁省部分地区人群及生活污水中polio病毒优势株调查

本文报道了1989年辽宁省部分地区正常人群及城镇生活污水中polio病毒调查结果,从211份正常人便中分离出13株polio病毒,11份污水中分离出3株polio病毒。16株polio病毒经Mcab和病毒RNA分析定为polio Sabin株,说明正常人群及外环境中的polio病毒主要是Sabin株。     

Occurrence of norovirus and other enteric viruses in untreated groundwaters of Korea

A total of 39 water samples from 23 different groundwater wells in Korea were collected and analyzed in order to monitor the occurrence of norovirus (NoV) and other indicator microbes as the first part of a national survey of groundwater. More than 500 L of untreated groundwater were filtered through 1MDS filters. Following elution and concentration by organic flocculation, PCR and sequence analysis were employed to detect and identify NoV, enterovirus, rotavirus, hepatitis A virus and adenovirus (Adv). Somatic and F-specific phages, heterotrophic bacteria, total coliforms and Escherichia coli were also analyzed to infer possible fecal contamination. NoVs were detected in 18% of the 39 samples. Five out of seven NoV-positive samples (71%) were identified as GI while the other two (29%) were GII. Enteroviruses and Advs were detected in two and three samples, respectively. Rotavirus and hepatitis A virus were not detected. Total coliforms, E. coli and coliphages were detected in 49, 15 and 13% of the samples, respectively, but did not appear to be suitable indicators of enteric virus contamination in groundwater. These results suggest that additional treatment may be needed for a significant number of groundwaters prior to use as drinking water.     

Water quality indicators: bacteria,coliphages, enteric viruses

Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. However, the presence of above-mentioned indicators do not always suggest the presence of human enteric viruses. It is important to study human enteric viruses in water. Human enteric viruses can tolerate fluctuating environmental conditions and survive in the environment for long periods of time becoming causal agents of diarrhoeal diseases. Therefore, the potential of human pathogenic viruses as significant indicators of water quality is emerging. Human Adenoviruses and other viruses have been proposed as suitable indices for the effective identification of such organisms of human origin contaminating water systems. This article reports on the recent developments in the management of water quality specifically focusing on human enteric viruses as indicators.     

Applicability of quantitative PCR for determination of removal efficacy of enteric viruses and Cryptosporidium by water treatment processes

This study aims to assess the applicability of quantitative PCR (qPCR) for removal studies of adenovirus, coxsackievirus, echovirus and Cryptosporidium by water treatment processes. Bench-scale coagulation jar tests were performed using the enteric viruses and Cryptosporidium. Standard methods (conventional cell-culture methods for the viruses and an immunofluorescence assay (IFA) for Cryptosporidium) were used to compare to qPCR. A significant correlation between microbial removals determined by qPCR and the standard detection methods and an approximate 1:1 correlation were observed for the challenge microorganisms. The results indicated that qPCR could be a satisfactory alternate for microbial removal studies using a relative quantification approach.     

Chemical and microbiological parameters as possible indicators for human enteric viruses in surface water

There are still conflicting results on the suitability of chemical and microbiological parameters as indicators for the viral contamination of surface waters. In this study, conducted over 20 months, the abundance of human adenovirus, human polyomavirus, enterovirus, group A rotavirus and norovirus was determined in Ruhr and Rhine rivers, Germany. Additionally, prevalence of different possible indicators such as somatic coliphages, E. coli, intestinal enterococci, and total coliforms was also considered. Moreover, the chemical parameter TCPP (tris-(2-chloro-, 1-methyl-ethyl)-phosphate), characterized by environmental stability and human origin, was included. Furthermore, chemical parameters (fluoride, chloride, nitrate, nitrite, bromide, phosphate, and sulfate) which may influence the stability and subsequently the detection rates of viruses in aquatic environment were measured. Quantitative Real-Time (RT-)PCR and double agar layer test were used for the quantification of human enteric viruses and somatic coliphages, respectively. The analyses for E. coli, total coliforms, and intestinal enterococci were done with respect to the standard reference method. The chemical parameters were measured by liquid chromatography of ions and by gas chromatography-flame photometer detector (GC-FPD), respectively. We demonstrated that human adenovirus had the highest detection rate (96.3%), followed by somatic coliphages (73.5%), human polyomavirus (68.6%), and rotavirus (63.5%). However, norovirus GII and enterovirus were found in only 25.7 and 17.8%, respectively. The concentration of the viral genome ranged between 16 and 1.1 × 10⁶ gen. equ./l (genome equivalents/l) whereas the concentrations for TCPP ranged between 0.01 and 0.9 μg/l. The results of the Pearson correlation showed no association between TCPP and any other microbiological parameter. None of the other tested chemical parameters correlated negatively, and therefore they do not influence the stability of enteric viruses. We conclude that neither TCPP nor any other chemical or microbiological parameter can be used as a reliable indicator for the presence of enteric viruses in river water.     

High prevalence of enteric viruses in untreated individual drinking water sources and surface water in Slovenia

Waterborne infections have been shown to be important in outbreaks of gastroenteritis throughout the world. Although improved sanitary conditions are being progressively applied, fecal contaminations remain an emerging problem also in developed countries. The aim of our study was to investigate the prevalence of fecal contaminated water sources in Slovenia, including surface waters and groundwater sources throughout the country. In total, 152 water samples were investigated, of which 72 samples represents groundwater from individual wells, 17 samples from public collection supplies and 63 samples from surface stream waters. Two liters of untreated water samples were collected and concentrated by the adsorption/elution technique with positively charged filters followed by an additional ultracentrifugation step. Group A rotaviruses, noroviruses (genogroups I and II) and astroviruses were detected with real-time RT-PCR method in 69 (45.4%) out of 152 samples collected, of which 31/89 (34.8%) drinking water and 38/63 (60.3%) surface water samples were positive for at least one virus tested. In 30.3% of drinking water samples group A rotaviruses were detected (27/89), followed by noroviruses GI (2.2%; 2/89) and astroviruses (2.2%; 2/89). In drinking groundwater samples group A rotaviruses were detected in 27 out of 72 tested samples (37.5%), genogroup I noroviruses in two (2.8%), and human astroviruses in one (1.4%) samples. In surface water samples norovirus genogroup GII was the most frequently detected (41.3%; 26/63), followed by norovirus GI (33.3%; 21/63), human astrovirus (27.0%; 17/63) and group A rotavirus (17.5%; 11/63). Our study demonstrates relatively high percentage of groundwater contamination in Slovenia and, suggests that raw groundwater used as individual drinking water supply may constitute a possible source of enteric virus infections. In the future, testing for enteric viruses should be applied for drinking water sources in waterborne outbreaks.     

饮用水中病毒的消毒技术研究进展

随着水源污染形势的加剧,各国对饮用水水质的要求将越来越严格,微生物指标作为其中一个重要的方面,病毒指标的引入以及针对病毒的消毒工艺的发展对饮用水标准的完善和保障各国人民的健康具有重大的意义。了解目前国内外针对病毒的消毒控制技术的研究进展,对不断完善我国饮用水标准、建立更安全的饮用水处理技术提供一定的理论指导和技术支持。因此,本文将从病毒对各种消毒技术的抗性比较、消毒的影响因素、新工艺的研究进展以及机制等四个方面进行综述。     

Virus removal efficiency of Cambodian ceramic pot water purifiers

Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.     

Ultraviolet-C irradiation for inactivation of viruses in foetal bovine serum

Foetal Bovine Serum (FBS) and porcine trypsin are one of the essential raw materials used in the manufacturing of cell culture based viral vaccines. Being from animal origin, these raw materials can potentially contaminate the final product by known or unknown adventitious agents. The issue is more serious in case of live attenuated viral vaccines, where there is no inactivation step which can take care of such adventitious agents. It is essential to design production processes which can offer maximum viral clearance potential for animal origin products. Ultraviolet-C irradiation is known to inactivate various adventitious viral agents; however there are limited studies on ultraviolet inactivation of viruses in liquid media. We obtained a recently developed UVivatec ultraviolet-C (UV-C) irradiation based viral clearance system for evaluating its efficacy to inactivate selected model viruses. This system has a unique design with spiral path of liquid allowing maximum exposure to UV-C light of a short wavelength of 254 nm. Five live attenuated vaccine viruses and four other model viruses were spiked in tissue culture media and exposed to UV-C irradiation. The pre and post UV-C irradiation samples were analyzed for virus content to find out the extent of inactivation of various viruses. These experiments showed substantial log reduction for the majority of the viruses with few exceptions based on the characteristics of these viruses. Having known the effect of UV irradiation on protein structure, we also evaluated the post irradiation samples of culture media for growth promoting properties using one of the most fastidious human diploid cells (MRC-5). UV-C exposure did not show any notable impact on the nutritional properties of culture media. The use of an UV-C irradiation based system is considered to be promising approach to mitigate the risk of adventitious agents in cell culture media arising through animal derived products.     

Chlorine inactivation of coliphage MS2 on strawberries by industrial-scale water washing units

Fruits and vegetables (produce) intended for minimal processing are often rinsed or washed in water. Chlorine and other sanitizers are used during washing to inactivate produce spoilage microbes, but such procedures may also inactivate pathogens epidemiologically linked to produce, such as hepatitis A virus (HAV). However, no information exists on the efficacy of chlorinated wash water to inactivate HAV and other viruses on produce in actual practice, because of obvious safety concerns. In contrast, coliphage MS2 (a bacterial virus) is commonly used as a surrogate for some pathogenic viruses and may be safely used in field studies. In the present investigation, strawberries seeded with MS2 were passed through industrial-scale water washing units operated with or without added sodium hypochlorite. MS2 on strawberries was inactivated by 68%, 92% and 96% at free chlorine (FC) concentrations of 2, 20 and 200 ppm in wash water, respectively. MS2 was detected in wash water containing 2 ppm FC in one trial, but was not detected in water containing 20 or 200 ppm FC. The presence and absence of MS2 in wash water containing various levels of FC highlight the importance of controlling sanitizer levels to prevent viral cross contamination of strawberries.