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Assessing microbial and chemical exposure risks of Giardia in indoor swimming pool water disinfected by chlorine

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Journal of Environmental Sciences 2022年第7期34卷 276-284页

作者： Chenyue Yin Bingjun Liu Kyu Hur shengkun dong Guangdong Engineering Technology Research Center of Water Security Regulation and Control for Southern China Guangzhou 510275China Southern Laboratory of Ocean Science and Engineering School of Civil EngineeringSun Yat-Sen UniversityZhuhai 519000China 3-10 Shinohara Nishicho Kohoku WardYokohamaKanagawa 222-0025Japan

Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations in pool water and reduce the microbial risk, higher chlorine doses are required during disinfection. Unfortunately, this process produces carcinogenic disinfection byproducts that increase the risk of chemical exposure. Therefore, quantitatively evaluating the comparative microbial vs. chemical exposure risks that stem from chlorination inactivation of Giardia in swimming pool water is an issue that demands attention. We simulated an indoor swimming pool disinfection scenario that followed common real-world disinfection practices. A quantitative microbial risk assessment coupled with a chemical exposure risk assessment was employed to compare the Giardia microbial exposure risk(MER) and the trihalomethane chemical exposure risk(CER) to humans. The results demonstrated a 22% decrease in MER-and CER-induced health exposure risk, from 8.45E-5 at 8:00 to 6.60E-5 at 19:00. Both the MER and CER decreased gradually, dropping to 3.26E-5 and 3.35E-5 at 19:00, respectively. However, the CER exceeded the MER after 18:30 and became the dominant factor affecting the total exposure risk. Past the 18 hr mark, the contribution of trihalomethane CER far exceeded the risk aversion from microbial inactivation, leading to a net increase in total exposure risk despite the declining MER. Swimmers may consider swimming after 19:00, when the total exposure risk is the lowest. Lowering water temperature and/or p H were identified as the most sensitive factors to minimize the overall health exposure risk.

关键词： Microbial risk Chemical risk Giardia Swimming pool Disinfection

Disinfection byproducts in indoor swimming pool water: Detection and human lifetime health risk assessment

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Journal of Environmental Sciences 2023年第4期126卷 378-386页

作者： Di Zhang shengkun dong Li Chen Rong Xiao Wenhai Chu State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China Southern Laboratory of Ocean Science and Engineering Key Laboratory of Water Cycle and Water Security in Southern China of Guangdong Higher Education InstituteSun Yat-sen UniversityGuangzhou 510275China

Quantification of regulated and emerging disinfection byproducts (DBPs) in swimming pool water,as well as the assessment of their lifetime health risk are limited in *** this study,the occurrence of regulated DBPs (e.g.,trihalomethanes,haloacetic acids) and emerging DBPs (e.g.,haloacetonitriles,haloacetaldehydes) in indoor swimming pool water and the corresponding source water at a city in Eastern China were *** concentrations of DBPs in swimming pool water were 1-2 orders of magnitude higher than that in source *** cancer and non-cancer risks of DBPs stemming from swimming pool water were also *** and dermal exposure were the most significant exposure routes related to swimming pool DBP cancer and non-cancer *** the first time,buccal and aural exposure were considered,and were proven to be important routes of DBP exposure (accounting for 17.9%-38.9%of total risk).The cancer risks of DBPs for all swimmers were higher than 10^(-6)of lifetime exposure risk recommended by United States Environmental Protection Agency,and the competitive adult swimmers experienced the highest cancer risk (7.82×10^(-5)).These findings provide important information and perspectives for future efforts to lower the health risks associated with exposure to DBPs in swimming pool water.

关键词： Health risk assessment Swimming pool water Disinfection byproducts Multiple exposure pathway

Comparative mammalian cell cytotoxicity of wastewater with elevated bromide and iodide after chlorination,chloramination, or ozonation

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Journal of Environmental Sciences 2017年第8期29卷 296-301页

作者： shengkun dong Thanh H.Nguyen Michael J.Plewa Department of Civil and Environmental Enoineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA Department of Crop Sciences University of Illinois at Urbana-Champaign Urbana IL 61801 USA Safe Global Water Institute Uniuersity of Illinois at Urbana-Champaign Urbana IL 61801 USA

Recycling wastewater is becoming more common as communities around the world try to better control their water resources against an increased frequency of either prolonged droughts or intense flooding. For communities in coastal areas, wastewaters may contain elevated levels of bromide（Br^-） and iodide（I^-） from seawater intrusion or high mineral content of source waters. Disinfection of such wastewater is mandatory to prevent the spread of pathogens, however little is known about the toxicity of wastewater after disinfection in the presence of Br^-and I^-. In this study we compared the induction of chronic cytotoxicity in mammalian cells in samples of municipal secondary wastewater effluent amended with elevated levels of Br^-/I^-after disinfection by chlorine, chloramines or ozone to identify which disinfection process generated wastewater with the lowest level of adverse biological response. Chlorination increased mammalian cell cytotoxicity by 5times as compared to non-disinfected controls. Chloramination produced disinfected wastewater that expressed 6.3 times more cytotoxicity than the non-disinfected controls and was 1.3 times more cytotoxic than the chlorinated samples. Ozonation produced wastewater with cytotoxicity comparable to the non-disinfected controls and was at least 4times less cytotoxic than the chlorine disinfected wastewaters. These results indicate that compared to chlorination and chloramination, ozonation of wastewater with high Br^-/Ilevels yielded the lowest mammalian cell cytotoxicity, suggesting its potential as a more favorable method to disinfect wastewater with minimizing the biological toxicity in mind.

关键词： Cytotoxicity Ozonation Chlorination Chloramination Wastewater Bromide Iodide Disinfection

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煤化工污泥的微生物种群结构与水分分布特征

中山大学学报（自然科学版）（中英文） 2024年第3期63卷 96-102页

作者：程子睿赵计辉董圣焜王奕仁何国锋柳金秋南京理工大学物理学院江苏南京210094 中山大学土木工程学院广东珠海519082 东莞理工学院生态环境与建筑工程学院广东东莞523000 中煤科工清洁能源股份有限公司北京100013

现代煤化工产业是实现煤炭资源清洁化利用的重要途径,煤化工生产过程会产生大量含水率高、脱水性差的煤化工污泥,是制约煤化工产业发展的典型难处理固废。煤化工污泥的脱水性受污泥中微生物种群结构及水分分布特征的影响,对其解析将有... 详细信息

现代煤化工产业是实现煤炭资源清洁化利用的重要途径,煤化工生产过程会产生大量含水率高、脱水性差的煤化工污泥,是制约煤化工产业发展的典型难处理固废。煤化工污泥的脱水性受污泥中微生物种群结构及水分分布特征的影响,对其解析将有助于揭示煤化工污泥的束水结构并可为煤化工污泥高效脱水方法的研发提供一定的理论指导。本研究以煤制烯烃污泥及煤制油污泥为研究对象,采用16s rRNA基因测序解析其微生物种群结构,通过差示扫描量热法(DSC,differential scanning calorimetry)和低场核磁共振法(LF-NMR,low-field nuclear magnetic resonance)表征污泥的水分分布特征。结果表明:两种煤化工产业选取的污水处理工艺不同,导致煤化工污泥的微生物种群结构存在一定差异,但变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和绿弯菌门(Chloroflexi)是两种污泥中的主要菌种;LF-NMR法测得水分分布更为准确,根据污泥中水的结合能可将其划分为结合水、机械结合水以及自由水,污泥中大部分水分(90%以上)为机械结合水;采用能够破坏污泥絮体及微生物群落结构的脱水方法,可以进一步实现煤化工污泥的高效、深度脱水。

关键词：煤化工污泥微生物种群结构高通量测序分析水分分布低场核磁

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复合改性技术对高掺量铁尾矿沥青混合料水稳定性的影响

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材料科学与工程学报 2023年第5期41卷 768-774页

作者：肖庆一董圣坤余天航龚芳媛赵振超河北工业大学土木与交通学院天津300401 云南省交通规划设计研究院有限公司云南昆明650041

本实验研究了SBS改性沥青、偶联剂及其复合改性技术对提升铁尾矿与沥青界面粘附效果。针对2个不同铁尾矿掺量、2种结合料及3种不同改性工艺进行了混合料配比设计及路用性能研究,分析了粘附效果的同时利用汉堡实验对长期水稳性能效果进... 详细信息

本实验研究了SBS改性沥青、偶联剂及其复合改性技术对提升铁尾矿与沥青界面粘附效果。针对2个不同铁尾矿掺量、2种结合料及3种不同改性工艺进行了混合料配比设计及路用性能研究,分析了粘附效果的同时利用汉堡实验对长期水稳性能效果进行了相关研究。结果表明,通过SBS改性沥青、偶联剂及其复合改性可以明显提高含铁尾矿混合料的水稳定性,整体路用性能也获得一定的提升,从宏观效果及微观指标证实了复合改性的粘附改性功效,并证实了复合改性技术显著提升含铁尾矿的耐久性。

关键词：沥青混合料铁尾矿水稳定性 SBS改性沥青偶联剂

64排螺旋CT头颈部CTA在血管性疾病中的临床应用

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影像研究与医学应用 2019年第7期3卷 6-7页

作者：丁圣玉张慧杰王书江许颖董生坤冯少华内蒙古满洲里市人民医院内蒙古满洲里021400

目的:探究64排螺旋CT头颈部CTA在血管性疾病中的实际应用效果。方法:将2017年2月—2018年10月本院收治的70例血管性疾病患者纳入本研究,均予以64排螺旋CT头颈部CTA检查,对其病例资料及检查结果予以回顾分析。结果:CTA显示,70例心血管疾... 详细信息

目的:探究64排螺旋CT头颈部CTA在血管性疾病中的实际应用效果。方法:将2017年2月—2018年10月本院收治的70例血管性疾病患者纳入本研究,均予以64排螺旋CT头颈部CTA检查,对其病例资料及检查结果予以回顾分析。结果:CTA显示,70例心血管疾病患者中共68例血管病变、2例正常。68例血管病变中包括18例颅内动脉瘤(25.71%,18/70)、17例颈总动脉狭窄(24.29%,18/70)、19例颅内动脉畸形(27.14%,19/70)、14例颈内动脉海绵窦瘘(20.00%,14/70);结论:64排螺旋CT头颈部可对头颈部的血管病变进行确诊,有助于为后续治疗及疗效评估提供重要的参考依据,可将其作为血管性疾病的首选检查方法。

关键词： 64排螺旋CT 头颈部CTA 血管性疾病

Exhaust Manifold TMF Analysis

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Exhaust Manifold TMF Analysis

2013中国汽车工程学会年会

作者： Zhao Qian dong Jin Wang Xijie Liu shengkun Lai Xiangfu ChongQing Hiter Automotive Exhaust systems Co.Ltd

＜正＞In this paper,a technique,combining CFD with FEA,is employed to simulate exhaust manifold TMF performance under thermal shock case.A in-line 4 cylinder engine exhaust manifold is exemplified to implement the *** on the results extracted from the prediction,the manifold structure optimization can be elicited,to effectively improve the high risk area of TMF,and to enhance the TMF performance and development efficiency,hence,the durability testing cost can commensurately be reduced.

关键词： Exhaust manifold TMF(Thermal Mechanical Fatigue) The equivalent plastic strain increments

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约束直接搜索法求解螺旋桨参数优化设计问题

上海交通大学学报 1997年第11期31卷 91-95页

作者：魏东张圣坤上海交通大学船舶与海洋工程学院

建立了螺旋桨参数优化设计的计算模型，包括初步设计和终结设计两部分，都可归结为三变量（螺旋桨盘面比、螺距比、进速系数）的非线性约束优化问题．提出了组合复合形法和自适应随机搜索法的混合方法，经过算例比较，可更有效地解决复... 详细信息

建立了螺旋桨参数优化设计的计算模型，包括初步设计和终结设计两部分，都可归结为三变量（螺旋桨盘面比、螺距比、进速系数）的非线性约束优化问题．提出了组合复合形法和自适应随机搜索法的混合方法，经过算例比较，可更有效地解决复杂的非线性优化问题．

关键词：螺旋桨最优设计约束直接搜索法船舶设计

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基于余度概念的船舶总纵剩余强度评估

上海交通大学学报 1998年第11期32卷 34-37页

作者：魏东张圣坤上海交通大学船舶与海洋工程学院

选取合适的概率余度衡准，并根据ＡＢＳ的要求列出船舶在触礁与碰撞损伤后的极限状态方程，可计算出船舶在事故损伤下的余度．为考虑疲劳腐蚀等必然损伤的影响，建立了船体梁层次的安全评估框架及对各类损伤定义对应余度的破坏水平，并... 详细信息

选取合适的概率余度衡准，并根据ＡＢＳ的要求列出船舶在触礁与碰撞损伤后的极限状态方程，可计算出船舶在事故损伤下的余度．为考虑疲劳腐蚀等必然损伤的影响，建立了船体梁层次的安全评估框架及对各类损伤定义对应余度的破坏水平，并根据模糊合成规则得到总体评估结果．算例表明，采用概率余度（相对指标）作为剩余强度衡准比确定性衡准和可靠性指标能获得更一致的结果．为反映评估中不确定性因素，利用模糊方法评估多种损伤下的船舶安全性是合理的．

关键词：结构失效余度评估船舶总纵剩余强度