水中挥发性卤代烃类有机物的吹扫捕集气相色谱质谱测定法

目的建立吹扫捕集气相色谱质谱法测定水中挥发性卤代烃类有机物的方法。方法对吹扫捕集和气相色谱等条件进行优化,并对实际水样进行实测分析。结果该方法最低检出限为0．06—0．24μg／L,精密度RSD〈3％,加标回收率在92％～106％之间。结论方法灵敏精确,适用于生活饮用水中多组分微量卤代烃的分析。     

饮用水中六价铬2种测定方法的比较

目的建立饮用水中微量六价铬的灵敏、快速的测定方法。方法在弱酸性溶液中,水中微量铬（VI）与二苯碳酰二肼和阴离子表面活性剂十二烷基硫酸钠反应形成紫红色三元离子缔合物,正丁醇存在的可被氯仿萃取,在波长550nm处比色定量。结果方法的线性范围为1～40μg/L,最低检测质量为0．1μg,最低检测质量浓度为0．001mg／L,方法的RSD为1．1％～1．4％,回收率为95％～110％。灵敏度是GB／T5750．6—2006《生活饮用水标准检验方法·金属指标》中的二苯碳酰二肼分光光度法的3．8倍。结论该方法灵敏准确,能满足生活饮用水卫生标准检验方法的要求。     

吹扫捕集-气相色谱法测定生活饮用水中挥发性有机物

目的采用吹扫捕集-气相色谱/质谱联用技术(P&T-GC/MS)快速分析生活饮用水中多组分微量挥发性有机物(VOCs)。方法对解析时间、烘焙时间、烘焙流速、捕集阱填充材料和比例等P&T的条件及GC条件进行优化,并对实际水样实测分析。结果本方法操作简单、省时,一次进样可实现多组分同时测定,具有较高的灵敏度和较广的分析范围,方法的线性范围为0·5~100μg/L,最低检出浓度可达0·01~0·5μg/L,相对标准偏差为1·24%~7·79%,加标回收率在90%~110%之间。结论本方法适用于生活饮用水中多组分微量VOCs的分析。     

石墨炉原子吸收法测定生活饮用水中的微量钡

目的建立一种涂镧石墨管原子吸收法测定生活饮用水中的微量钡。方法以硝酸镁为基体改进剂，硝酸为介质，采用涂镧石器管，无火焰原子吸收法对生活饮用水中微量钡进行测定。结果方法回收率90．0％～106．7％，线性范围10～1000μg／L，检测下限10μg/L,r〉0．9997，RSD〈7．7％（n=6）。结论本方法克服了钡的记忆效应，精密度好，线性范围宽，适用于生活饮用水中钡的测定。     

生活饮用水中5 种卤代烃的吹扫捕集气相色谱质谱测定法

目的建立同时测定生活饮用水中5种卤代烃的吹扫捕集气相色谱质谱法。方法应用吹扫捕集技术,对生活饮用水中三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯和三溴甲烷5种卤代烃进行气相色谱-质谱法（GC—MS）分析。结果5种卤代烃在4min内分析完成,方法的最低检出浓度为0．18～0．23μg/L,最低定量浓度为0．59—0．76μg／L,水样加标回收率为90．3％。107．4％,RSD％为2．3％～3．3％。结论该法简单、准确,灵敏度和精密度高,可应用于测定生活饮用水中5种卤代烃。     

顶空气相色谱质谱法测定软饮料中的微量苯

目的：建立顶空气相色谱质谱联用法测定软饮料中的微量苯。方法：采用静态顶空技术提取饮料样品中的微量苯，顶空温度为80℃，平衡时间为30min，DB-5ms毛细管气相色谱柱分离苯与其他干扰物，采用质谱选择离子监测方式进行检测，保留时间定性，外标法定量，并依据选择离子丰度比进行确证。结果：苯在0.5～50.0μg／L范围内线性相关系数为0．996，回收率在85．2％～112．5％之间，相对标准偏差小于6％，测定低限为0．1μg／L。结论：该方法简单、准确、灵敏度高，适合于软饮料中微量苯的测定。     

次灵敏线石墨炉原子吸收法直接测定饮用水中微量锰

目的：探讨用次灵敏线石墨炉原子吸收法直接测定饮用水中微量锰，增大直接测定饮用水中微量锰的线性范围。方法：通过比较选择，以磷酸二氢铵为基体改进剂，在适宜的干燥、灰化、原子化温度下，直接进样测定。结果：饮用水锰浓度为0～200μg/L，方法线性关系良好，相关系数r〉0．999。检出限为0．03μg/L，加标回收率为95．2％～100．2％，相对标准偏差为1．07％～2．39％。结论：方法简便，灵敏度高，线性范围广，适宜测定生活饮用水中锰。     

饮用水中苯甲醚和8种苯系物的吹扫捕集-气相色谱-质谱联用测定法

目的建立同时测定生活饮用水中苯甲醚和8种苯系物(苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯、异丙苯、苯乙烯)的吹扫捕集-气相色谱-质谱联用方法。方法采用吹扫捕集的方法对水中的苯甲醚和苯系物进行富集,解吸后进入气相色谱-质谱联用仪,经色谱柱分离后,质谱检测器检测测定。结果方法的线性范围分别为0.73~47.0μg/L(异丙苯)和0.78~50.0μg/L(其余8种化合物),检出限为0.16~0.23μg/L,回收率为84.0%~120%,RSD为0.6%~5.0%。结论该方法灵敏度高、重现性好、操作简单、无需有机溶剂,适用于饮用水中苯甲醚和8种苯系物的同时测定。     

超高效液相色谱/串联质谱分析生活饮用水中莠去津和灭草松

目的：建立超高效液相色谱-电喷雾串联四极杆质谱快速测定生活饮用水中莠去津、灭草松的方法。方法：水样经WatersOasisHLB固相萃取净化，应用超高效液相色谱／电喷雾串联四极杆质谱仪多离子反应监测（MRM）定量法检测莠去津、灭草松，建立了定量检测生活饮用水中莠去津、灭草松的快速、准确、高灵敏度的方法。结果：经方法学验证。该方法对莠去津、灭草松的最低检出限LOD分别为0．08、0．8μg／L（进样量10μl），最低定量限LOQ分别是0．1、1．0μg/L。在1．0～100．0μg／L的线性范围中，相关系数r〉0．9999，回收率：87．6％～103．0％。结论：方法灵敏度高、操作简单、定量准确、测定浓度范围宽阔，是环境水质样品中莠去津、灭草松含量检测的理想方法。     

2008年滨州市黄河以南地区居民饮用水碘含量调查

[目的]了解滨州市黄河以南地区居民饮用水水碘含量,了解居民碘营养状况,科学的指导碘缺乏病防治工作。[方法]2008年7～8月,对邹平县和博兴县居民饮用水进行碘含量检测。[结果]检测水样1298份,水碘含量为（93·85±134．86）μg／L,中位数为36．15μg／L,检出值范围为0．07－680．92μg／L。其中,碘含量〈10μg／L的占33·90％·10～49ug／L的占21．ii％．50～99μg／L的占13．56％,100～149μg／L的占7．55％·150～300μg／L的占15·79％,〉300μg／L的占8．09％。水碘含量〈10μg／L者所占比例,邹平县为42．82％,博兴县为14．66％（P〈0.01）;多村联合供水的为6．25％,单村统一供水为35．40％（P〈0．01）。29个乡镇中水碘中位数〈10μg／L的9个,〉150μg／L的6个。[结论]邹平县和博兴县居民饮用水以缺碘和碘适量为主,局部乡村存在一定数量的高碘水。     

Shigella Infections in Household Contacts of Pediatric Shigellosis Patients in Rural Bangladesh

To examine rates of Shigella infections in household contacts of pediatric shigellosis patients, we followed contacts and controls prospectively for 1 week after the index patient obtained care. Household contacts of patients were 44 times more likely to develop a Shigella infection than were control contacts (odds ratio 44.7, 95% CI 5.5–361.6); 29 (94%) household contacts of shigellosis patients were infected with the same species and serotype as the index patient’s. Pulsed-field gel electrophoresis showed that 14 (88%) of 16 with infected contacts had strains that were indistinguishable from or closely related to the index patient’s strain. Latrine area fly counts were higher in patient households compared with control households, and 2 patient household water samples were positive for Shigella. We show high susceptibility of household contacts of shigellosis patients to Shigella infections and found environmental risk factors to be targeted in future interventions.     

Decline in Decreased Cephalosporin Susceptibility and Increase in Azithromycin Resistance in Neisseria gonorrhoeae,Canada

Antimicrobial resistance profiles were determined for Neisseria gonorrhoeae strains isolated in Canada during 2010–2014. The proportion of isolates with decreased susceptibility to cephalosporins declined significantly between 2011 and 2014, whereas azithromycin resistance increased significantly during that period. Continued surveillance of antimicrobial drug susceptibilities is imperative to inform treatment guidelines.     

Salmonella control programs in Denmark

We describe Salmonella control programs of broiler chickens, layer hens, and pigs in Denmark. Major reductions in the incidence of foodborne human salmonellosis have occurred by integrated control of farms and food processing plants. Disease control has been achieved by monitoring the herds and flocks, eliminating infected animals, and diversifying animals (animals and products are processed differently depending on Salmonella status) and animal food products according to the determined risk. In 2001, the Danish society saved U.S.$25.5 million by controlling Salmonella. The total annual Salmonella control costs in year 2001 were U.S.$14.1 million (U.S.$0.075/kg of pork and U.S.$0.02/kg of broiler or egg). These costs are paid almost exclusively by the industry. The control principles described are applicable to most industrialized countries with modern intensive farming systems.     

Bacteremic typhoid fever in children in an urban slum, Bangladesh

We confirmed a bacteremic typhoid fever incidence of 3.9 episodes/1,000 person-years during fever surveillance in a Dhaka urban slum. The relative risk for preschool children compared with older persons was 8.9. Our regression model showed that these children were clinically ill, which suggests a role for preschool immunization.     

Novel lyssavirus in Natterer's bat, Germany

A virus isolated from a Natterer's bat (Myotis nattererii) in Germany was differentiated from other lyssaviruses on the basis of the reaction pattern of a panel of monoclonal antibodies. Phylogenetic analysis supported the assumption that the isolated virus, Bokeloh bat lyssavirus, may represent a new member of the genus Lyssavirus.     

Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance

Pneumocystis pneumonia (PCP) remains a major cause of illness and death in HIV-infected persons. Sulfa drugs, trimethoprim-sulfamethoxazole (TMP-SMX) and dapsone are mainstays of PCP treatment and prophylaxis. While prophylaxis has reduced the incidence of PCP, its use has raised concerns about development of resistant organisms. The inability to culture human Pneumocystis, Pneumocystis jirovecii, in a standardized culture system prevents routine susceptibility testing and detection of drug resistance. In other microorganisms, sulfa drug resistance has resulted from specific point mutations in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim for PCP treatment remains unclear. We review studies of DHPS mutations in P. jirovecii and summarize the evidence for resistance to sulfamethoxazole and dapsone.     

Congenital Transmission of Chagas Disease in Latin American Immigrants in Switzerland

International migration has changed the epidemiologic patterns of Chagas disease. Recently, 2 cases of Chagas disease transmitted from Latin American women to their newborns were diagnosed in Geneva, Switzerland. A retrospective study to detect Chagas disease showed a prevalence of 9.7% among 72 Latin American women tested during pregnancy in Switzerland.     

A Comparison of Short-term and Long-term Air Pollution Exposure Associations with Mortality in Two Cohorts in Scotland

Background: Air pollution-mortality risk estimates are generally larger at longer-term, compared with short-term, exposure time scales.Objective: We compared associations between short-term exposure to black smoke (BS) and mortality with long-term exposure-mortality associations in cohort participants and with short-term exposure-mortality associations in the general population from which the cohorts were selected.Methods: We assessed short-to-medium-term exposure-mortality associations in the Renfrew-Paisley and Collaborative cohorts (using nested case-control data sets), and compared them with long-term exposure-mortality associations (using a multilevel spatiotemporal exposure model and survival analyses) and short-to-medium-term exposure-mortality associations in the general population (using time-series analyses).Results: For the Renfrew-Paisley cohort (15,331 participants), BS exposure-mortality associations were observed in nested case-control analyses that accounted for spatial variations in pollution exposure and individual-level risk factors. These cohort-based associations were consistently greater than associations estimated in time-series analyses using a single monitoring site to represent general population exposure {e.g., 1.8% [95% confidence interval (CI): 0.1, 3.4%] vs. 0.2% (95% CI: 0.0, 0.4%) increases in mortality associated with 10-μg/m3 increases in 3-day lag BS, respectively}. Exposure-mortality associations were of larger magnitude for longer exposure periods [e.g., 3.4% (95% CI: -0.7, 7.7%) and 0.9% (95% CI: 0.3, 1.5%) increases in all-cause mortality associated with 10-μg/m3 increases in 31-day BS in case-control and time-series analyses, respectively; and 10% (95% CI: 4, 17%) increase in all-cause mortality associated with a 10-μg/m3 increase in geometic mean BS for 1970-1979, in survival analysis].Conclusions: After adjusting for individual-level exposure and potential confounders, short-term exposure-mortality associations in cohort participants were of greater magnitude than in comparable general population time-series study analyses. However, short-term exposure-mortality associations were substantially lower than equivalent long-term associations, which is consistent with the possibility of larger, more persistent cumulative effects from long-term exposures.