Cluster randomized controlled trial of the plastic BioSand Water filter in Cambodia

About half of the rural population of Cambodia lacks access to improved water; an even higher percentage lacks access to latrines. More than 35,000 concrete BioSand Water filters (BSF) have been installed in the country. However, the concrete BSF takes time to produce and weighs hundreds of pounds. A plastic BSF has been developed but may not perform to the same benchmarks established by its predecessor. To evaluate plastic BSF performance and health impact, we performed a cluster randomized controlled trial in 13 communities including 189 households and 1147 participants in the Angk Snoul district of Kandal Province from May to December 2008. The results suggest that villages with plastic BSFs had significantly lower concentrations of E. coli in drinking water and lower diarrheal disease (incidence rate ratio 0.41, 95% confidence interval: 0.24-0.69) compared to control villages. As one of the first studies on the plastic BSF in Cambodia, these are important findings, especially in a setting where the concrete BSF has seen high rates of continued use years after installation. The study suggests the plastic BSF may play an important role in scaling up the distribution/implementation of the BSF, potentially improving water quality and health in the region.     

Randomized intervention study of solar disinfection of drinking water in the prevention of dysentery in Kenyan children aged under 5 years

We report the results of a randomized controlled intervention study (September 2007 to March 2009) investigating the effect of solar disinfection (SODIS) of drinking water on the incidence of dysentery, nondysentery diarrhea, and anthropometric measurements of height and weight among children of age 6 months to 5 years living in peri-urban and rural communities in Nakuru, Kenya. We compared 555 children in 404 households using SODIS with 534 children in 361 households with no intervention. Dysentery was recorded using a pictorial diary. Incidence rate ratios (IRR) for both number of days and episodes of dysentery and nondysentery diarrhea were significantly (P < 0.001) reduced by use of solar disinfection: dysentery days IRR = 0.56 (95% CI 0.40 to 0.79); dysentery episodes IRR = 0.55 (95% CI 0.42 to 0.73); nondysentery days IRR = 0.70 (95% CI 0.59 to 0.84); nondysentery episodes IRR = 0.73 (95% CI 0.63 to 0.84). Anthropometry measurements of weight and height showed median height-for-age was significantly increased in those on SODIS, corresponding to an average of 0.8 cm over a 1-year period over the group as a whole (95% CI 0.7 to 1.6 cm, P = 0.031). Median weight-for-age was higher in those on SODIS, corresponding to a 0.23 kg difference in weight over the same period; however, the confidence interval spanned zero and the effect fell short of statistical significance (95% CI -0.02 to 0.47 kg, P = 0.068). SODIS and control households did not differ in the microbial quality of their untreated household water over the follow-up period (P = 0.119), but E. coli concentrations in SODIS bottles were significantly lower than those in storage containers over all follow-up visits (P < 0.001). This is the first trial to show evidence of the effect of SODIS on childhood anthropometry, compared with children in the control group and should alleviate concerns expressed by some commentators that the lower rates of dysentery associated with SODIS are the product of biased reporting rather than reflective of genuinely decreased incidence.     

Study on the structure and mutagenicity of a new disinfection byproduct in chlorinated drinking water

The structure of a new chlorinated disinfection byproduct (DBP) in drinking water is studied. The new DBP was prepared through chlorinating its best precursor, and it was extracted and isolated from the chlorination products. Its structure is identified as 2,2,4-trichloro-5-methoxycyclopent-4-ene-1,3-dione (TCMCD) through FTIR, MS, 1H NMR, and 13C NMR spectroscopic analysis and single-crystal X-ray diffraction method. Results of the Ames test with tester strain TA100 indicated that the newly identified DBP TCMCD is a mutagen.     

Tribromopyrrole,brominated acids,and other disinfection byproducts produced by disinfection of drinking water rich in bromide

Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comprehensive investigation of DBPs formed by chlorine dioxide under high bromide conditions. Drinking water from full-scale treatment plants in Israel was studied, along with source water (Sea of Galilee) treated under carefully controlled laboratory conditions. Select DBPs (trihalomethanes, haloacetic acids, aldehydes, chlorite, chlorate, and bromate) were quantified. Many of the DBPs identified have not been previously reported, and several of the identifications were confirmed through the analysis of authentic standards. Elevated bromide levels in the source water caused a significant shift in speciation to bromine-containing DBPs; bromoform and dibromoacetic acid were the dominant DBPs observed, with very few chlorine-containing compounds found. Iodo-trihalomethanes were also identified, as well as a number of new brominated carboxylic acids and 2,3,5-tribromopyrrole, which represents the first time a halogenated pyrrole has been reported as a DBP. Most of the bromine-containing DBPs were formed during pre-chlorination at the initial reservoir, and were not formed by chlorine dioxide itself. An exception wasthe iodo-THMs, which appeared to be formed by a combination of chlorine dioxide with chloramines or chlorine (either added deliberately or as an impurity in the chlorine dioxide). A separate laboratory study was also conducted to quantitatively determine the contribution of fulvic acids and humic acids (from isolated natural organic matter in the Sea of Galilee) as precursor material to several of the DBPs identified. Results showed that fulvic acid plays a greater role in the formation of THMs, haloacetic acids, and aldehydes, but 2,3,5-tribromopyrrole was produced primarily from humic acid. Because this was the first time a halopyrrole has been identified as a DBP, 2,3,5-tribromopyrrole was tested for mammalian cell cytotoxicity and genotoxicity. In comparison to other DBPs, 2,3,5-tribromopyrrole was 8x, 4.5x, and 16x more cytotoxic than dibromoacetic acid, 3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone [MX], and potassium bromate, respectively. 2,3,5-Tribromopyrrole also induced acute genomic damage, with a genotoxic potency (299 microM) similar to that of MX.     

饮用水中交链孢霉毒素氯消毒副产物鉴定及其毒性作用评价

目的 研究水中交链孢菌酮酸(TeA)和腾毒素(TEN)在氯消毒过程中的反应动力学特征,对产生的氯消毒副产物(DBPs)进行结构鉴定,并对其消毒副产物的细胞毒性进行初步探索。方法 本研究通过实验室模拟其消毒反应过程,研究其反应动力学特征,利用超高效液相色谱-串联四级杆飞行时间质谱(UPLC-Q-TOF/MS)和核磁共振波谱对反应产物进行结构鉴定并初步评价其毒性。结果 TeA氯消毒反应可生成2种氯消毒副产物DBP-188和DBP-240,而TEN氯代反应很慢未观察到氯消毒副产物的产生。反应动力学试验表明TEN与氯的反应速率随着反应体系中氯浓度和pH值的增加而升高。体外毒性预测分析发现TeA的氯消毒副产物经口毒性、发育毒性和致癌性均高于母体。结论 交链孢霉毒素经过氯消毒会产生氯消毒副产物,反应过程受pH值与氯浓度的影响,氯消毒副产物的预测毒性高于母体,细胞试验证明了TeA氯消毒副产物具有一定的细胞毒性。     

A multisite,randomized field trial to evaluate the influence of lactoferrin on the morbidity and mortality of dairy calves with diarrhea

Diarrhea is one of the most common causes of antimicrobial use and mortality in young calves. To reduce antimicrobial use and resistance on dairy farms, research on alternative therapies for calf diarrhea is necessary. Our laboratory previously conducted a randomized clinical trial investigating the effectiveness of lactoferrin, an iron-binding protein found in colostrum, as a treatment for calf diarrhea. The trial showed significantly reduced calf mortality in diarrheic calves that were administered lactoferrin. Thus, the objective of this study was to corroborate the results of our prior clinical trial across multiple farms and to investigate the effect of lactoferrin on the morbidity and mortality of preweaned calves with naturally occurring cases of diarrhea. This randomized field trial was conducted on 5 commercial dairy farms in Ohio. In total, 485 calves (≤21 d of age) were enrolled at first diarrhea diagnosis (fecal score ≥2 defined as loose to watery) and randomly assigned to receive an oral dose of lactoferrin (3 g of lactoferrin powder dissolved in 30 mL of water) or 30 mL of water (control) once daily for 3 consecutive days. Health assessments were conducted on the day of diarrhea diagnosis (d 0) and 1, 2, 3, 7, 14, 21, 28, and 35 d following diagnosis. Producer records of disease treatment and mortality were collected 120 d following diagnosis. A Poisson regression model was used to test differences between treatments in disease frequency through 35 d post-diarrhea diagnosis and the incidence risk of treatment and mortality risk 120 d post-diarrhea diagnosis; the model controlled for calf age at enrollment, farm, and treatment. Median calf age at enrollment was 11 d and ranged from 1 to 26 d of age. At study enrollment, 51.3% (123/240) and 52.2% (128/245) of calves in the control and lactoferrin treatment groups, respectively, were diagnosed with severe diarrhea (fecal score = 3). The frequency of disease (diarrhea, dehydration, depression, signs of respiratory disease) through 35 d following diarrhea diagnosis was not significantly different for calves in the lactoferrin and control groups. Overall mortality risk for enrolled calves was 9.9%, and 10.7% (22/243) and 9.1% (26/242) of calves in the lactoferrin and control groups, respectively, died or were culled in the 120 d following diarrhea diagnosis. The relative risk of death or culling did not differ between treatment groups, however. Therefore, as performed in this study, lactoferrin as a treatment for calf diarrhea was not beneficial.     

Microbiological effectiveness and cost of boiling to disinfect drinking water in rural Vietnam

Despite certain shortcomings, boiling is still the most common means of treating water in the home and the benchmark against which alternative household-based disinfection and filtration methods must be measured. We assessed the microbiological effectiveness and cost of boiling among a vulnerable population relying on unimproved water sources and commonly practicing boiling as a means of disinfecting water. In a 12 week study among 50 households from a rural community in Vietnam, boiling was associated with a 97% reduction in geometric mean thermotolerant coliforms (TTCs) (p < 0.001). Despite high levels of faecal contamination in source water, 37% of stored water samples from self-reported boilers met the WHO standard for safe drinking water (0 TTC/100 mL), and 38.3% fell within the low risk category (1--10 TTC/100 mL). Nevertheless, 60.5% of stored drinking water samples were positive for TTC, with 22.2% falling into the medium risk category (11--100 TTC/100 mL). The estimated cost of wood used to boil water was US$ 0.272 per month for wood collectors and US$ 1.68 per month for wood purchasers, representing approximately 0.48% to 1.04%, respectively, of the average monthly income of participating households.     

Impact of UV disinfection combined with chlorination/chloramination on the formation of halonitromethanes and haloacetonitriles in drinking water

The application of UV disinfection in water treatment is increasing due to both its effectiveness against protozoan pathogens, and the perception that its lack of chemical inputs would minimize disinfection byproduct formation. However, previous research has indicated that treatment of nitrate-containing drinking waters with polychromatic medium pressure (MP), but not monochromatic (254 nm) low pressure (LP), UV lamps followed by chlorination could promote chloropicrin formation. To better understand this phenomenon, conditions promoting the formation of the full suite of chlorinated halonitromethanes and haloacetonitriles were studied. MP UV/postchlorination of authentic filter effluent waters increased chloropicrin formation up to an order of magnitude above the 0.19 μg/L median level in the U.S. EPA's Information Collection Rule database, even at disinfection-level fluences (<300 mJ/cm(2)) and nitrate/nitrite concentrations (1.0 mg/L-N) relevant to drinking waters. Formation was up to 2.5 times higher for postchlorination than for postchloramination. Experiments indicated that the nitrating agent, NO(2)(?), generated during nitrate photolysis, was primarily responsible for halonitromethane promotion. LP UV treatment up to 1500 mJ/cm(2) did not enhance halonitromethane formation. Although MP UV/postchloramination enhanced dichloroacetonitrile formation with Sigma-Aldrich humic acid, formation was not significant in field waters. Prechlorination/MP UV nearly doubled chloropicrin formation compared to MP UV/postchlorination, but effects on haloacetonitrile formation were not significant.     

Arsenic and manganese contamination of drinking water resources in Cambodia: coincidence of risk areas with low relief topography

Arsenic contamination of groundwater has been identified in Cambodia, where some 100,000 family-based wells are used for drinking water needs. We conducted a comprehensive groundwater survey in the Mekong River floodplain, comprising an area of 3700 km(2) (131 samples, 30 parameters). Seasonal fluctuations were also studied. Arsenic ranged from 1 to 1340 microg L(-1) (average 163 microg L(-1)), with 48% exceeding 10 microg L(-1). Elevated manganese levels (57% >0.4 mg L(-1)) are posing an additional health threat to the 1.2 million people living in this area. With 350 people km(-2) potentially exposed to chronic arsenic poisoning, the magnitude is similar to that of Bangladesh (200 km(-2)). Elevated arsenic levels are sharply restricted to the Bassac and Mekong River banks and the alluvium braided by these rivers (Kandal Province). Arsenic in this province averaged 233 microg L(-1) (median 100 microg L(-1)), while concentrations to the west and east of the rivers were <10 microg L(-1). Arsenic release from Holocene sediments between the rivers is most likely caused by reductive dissolution of metal oxides. Regions exhibiting low and elevated arsenic levels are co-incident with the present low relief topography featuring gently increasing elevation to the west and east of a shallow valley-understood as a relict of pre-Holocene topography. The full georeferenced database of groundwater analysis is provided as Supporting Information.     

顶空-气相色谱法测定5种挥发性消毒副产物在饮用水加热前后的含量变化

目的建立顶空气相色谱法测定生活饮用水在加热前后5种挥发性消毒副产物三氯甲烷、四氯化碳、一溴二氯甲烷、二溴一氯甲烷、三溴甲烷含量的变化。方法取出厂水、末梢水、煮沸的开水、敞口持续煮沸1 min的开水各10 mL于顶空瓶中70℃顶空平衡15 min,取上层气体进样进行气相色谱分析, HP-5毛细管色谱柱分离,电子捕获检测器检测,外标法定量。结果 5种挥发性消毒副产物在不同的浓度下线性关系良好,相关系数为0.9992～0.9996;加标回收率为83.3%～101.8%。其中三氯甲烷在4种样品中检出浓度为0.717～44.9μg/L;四氯化碳、一溴二氯甲烷、二溴一氯甲烷均有不同程度检出,三溴甲烷均未检出。结论经过氯化消毒的自来水煮沸后,挥发性消毒副产物含量大幅降低,其中以开盖持续煮沸1min的开水中含量最低,因此建议饮用自来水需要提前煮沸。     

江西部分城乡生活饮用水现状监测分析与评估

目的 通过江西城乡各种水体的监测, 了解掌握水质卫生状况, 便于水质管理、规划。方法 在江西部分城乡随机采集不同来源的生活饮用水106份, 按国标方法对理化性质、微生物指标等进行检测评价。结果 不同类型的水样水质总合格率为69.8%, 影响水质的主要影响因素为微生物污染, 农村的水质合格率低于城镇, 江西省水质合格率低于国家标准。结论 江西省城乡水质仍需进行改善。     

Learning to dislike safe water products: results from a randomized controlled trial of the effects of direct and peer experience on willingness to pay

Low-cost point-of-use (POU) safe water products have the potential to reduce waterborne illness, but adoption by the global poor remains low. We performed an eight-month randomized trial of four low-cost household water treatment products in Dhaka, Bangladesh. Intervention households (n = 600) received repeated educational messages about the importance of drinking safe water along with consecutive two-month free trials with each of four POU products in random order. Households randomly assigned to the control group (n = 200) did not receive free products or repeated educational messages. Households' willingness to pay for these products was quite low on average (as measured by bids in an incentive-compatible real-money auction), although a modest share was willing to pay the actual or expected retail price for low-cost chlorine-based products. Furthermore, contrary to our hypotheses that both one's own personal experience and the influence of one's peers would increase consumers' willingness to pay, direct experience significantly decreased mean bids by 18-55% for three of the four products and had no discernible effect on the fourth. Neighbor experience also did not increase bids. Widespread dissemination of safe water products is unlikely until we better understand the preferences and aspirations of these at-risk populations.     

Impact of salt reduction interventions on salt taste sensitivity and liking,a cluster randomized controlled trial

BackgroundExcessive intake of salt is associated with high blood pressure, a risk factor for cardiovascular disease. Moreover, a high salt consumption has been related to a reduced salt taste sensitivity, and an increased liking of high salt content foods. Whether a reduction in salt intake over a long period of time can increase salt taste sensitivity and liking of foods with lower salt content requires further research.ObjectiveThis study aims to investigate the effect of gradually lowering salt content in bread, either alone or in combination with dietary counselling, on salt taste sensitivity and liking of salt reduced bread.MethodsA four-month, single blinded, cluster RCT with a parallel design was conducted among Danish families. Families were randomized to receive bread gradually reduced in salt content (Intervention A), bread gradually reduced in salt content in combination with dietary counselling (Intervention B) or bread with regular salt content (control). Salt taste detection thresholds (DT) and recognition thresholds (RT) were measured at baseline and follow-up. Moreover, overall liking of bread with very low (0.4 g/100 g), low (0.8 g/100 g) and normal (1.2 g/100 g) salt content was measured using a 7-point hedonic scale.ResultsEighty-nine families (n = 215) participated in the study. No significant differences between groups were found for DT or RT, but a significant reduction in DT of 18% (−28, −7) and a trend towards a reduction in RT of −16% (−30, 2) was found in Intervention B from baseline to follow-up. The intervention resulted in significantly higher liking of bread with 0.4 g salt/100 g in intervention B compared to the control and borderline significantly higher liking in intervention A compared to the control (p-value = 0.055). No differences were seen between groups in liking of bread with 0.8 g and 1.2 g salt/100 g. From baseline to follow-up all three groups reduced their liking of bread with 1.2 g salt/100 g and in the control group liking of bread with 0.4 g salt/100 g was significantly reduced.ConclusionReducing salt intake by lowering salt content in bread and receiving dietary counselling increased salt taste sensitivity (baseline to follow-up) and resulted in higher liking of bread with very low salt content (0.4 g salt/100 g) compared to control.     

2014~2016年保山市农村饮用水卫生状况监测分析

目的 调查保山市农村地区饮用水水质现状, 为改善保山市农村饮水水质卫生状况、预防介水传染病提供科学依据。方法 采集农村集中式供水水样1404份, 水样按照《生活饮用水标准检验方法》(GB/T 5750-2006)进行感官性状和一般化学指标、毒理学指标、微生物指标等31个指标的检验, 按照《生活饮用水卫生标准》(GB 5749-2006)进行评价。采用χ2检验进行率的比较分析。结果 2014~2016年共检测农村地区饮用水1404份, 合格521份, 合格率为37.11%, 其中微生物指标合格率最低(46.72%); 水样合格率随年份增加而升高(χ2=120.174, P<0.001)。感官性状和一般化学指标合格率枯水期(74.36%)高于丰水期(66.81%), 有统计学差异(χ2=9.636, P=0.002); 微生物指标合格率丰水期(52.14%)高于枯水期(41.31%), 有统计学差异(χ2=16.527, P<0.001); 水样合格率常规处理(包含混凝、沉淀、过滤、消毒)>仅消毒>未处理>沉淀/过滤(χ2=264.479, P<0.001); 水样合格率随供水能力的增加而增加(χ2=8.420, P=0.004)。结论 保山市农村地区饮用水水质合格率低, 微生物指标是影响保山市农村地区饮用水安全的主要因素, 水期类型、供水方式、水样类型、供水能力是水质卫生状况的影响因素。为保证该市农村地区饮用水的卫生、安全, 有关部门亟待采取有效的措施, 提高农村地区水质, 保护人民群众的健康。     

The effect of environmental temperature on average daily gain in preweaned calves: A randomized controlled trial and Bayesian analysis

Neonatal calves are relatively susceptible to heat loss, and previous research suggests that reduced environmental temperatures are associated with reduced average daily gain (ADG) during the preweaning phase. Current methods of mitigating negative effects of colder environmental conditions include the use of calf jackets and the provision of supplementary heat sources; however, previous research is limited. The aim of this study was to evaluate the effect of calf jackets and 1-kW heat lamps on the growth rates of preweaning calves and evaluate associations between environmental temperature and ADG using a Bayesian approach to incorporate both current and previous data. Seventy-nine calves from a single British dairy farm were randomly allocated at birth to 1 of the following 4 groups: no jacket and no heat lamp, heat lamp but no jacket, jacket but no heat lamp, or both heat lamp and jacket between January and April of 2021. Calves were weighed at both birth and at approximately 21 d of age. Temperature was recorded both inside and outside of the calf building, and in pens both with and without heat lamps using data loggers. To explore the effect of treatment group and environmental temperature on ADG, a fixed effects model was fitted over 1,000 bootstrap samples. The effect of environmental temperature on ADG was further explored within a Bayesian framework that used temperature and ADG data for 484 calves from 16 farms available from a previous trial as prior information. Calves housed under a 1-kW heat lamp had an increased ADG of 0.09 kg/d (95% bootstrap confidence interval: ?0.02 to 0.20 kg/d), and no effect of jacket or interactions between jacket and heat lamp were found. A significant positive association was identified between the mean environmental temperature of the calf building and ADG, with a 1°C increase in temperature being associated with a 0.03 kg/d increase in ADG (95% bootstrap confidence interval: 0.01 to 0.04 kg/d). Associations between environmental temperature and ADG were further evaluated within a Bayesian framework, and posterior estimates were 0.014 kg/d of ADG per 1°C increase (95% credible interval: 0.009 to 0.021 kg/d). This study demonstrated that a 1-kW heat lamp was effective in increasing ADG in calves, and no significant effect of calf jacket on ADG was found. A significant, positive effect of increased pen temperature on calf ADG was identified in this study and was reinforced when including prior information from previous research within a Bayesian framework.     

Moderate consumption of wine,through both its phenolic compounds and alcohol content,promotes hydroxytyrosol endogenous generation in humans. A randomized controlled trial

In humans, urinary hydroxytyrosol (OHTyr) concentrations have been associated to alcohol and wine consumption. To explore the role of wine components on promoting an endogenous OHTyr generation we performed a cross‐over, double‐blind, randomized controlled clinical trial (n = 28 healthy volunteers). Ethanol (wine and vodka), dealcoholized wine, and placebo were administered. Alcohol, dealcoholized wine, and particularly wine promoted a de novo OHTyr generation in vivo in humans. Potential OHTyr precursors (tyrosine, tyrosol, tyramine) were investigated in rats. Tyrosol was metabolized to OHTyr. Collating both studies, it is postulated that an increased Tyr bioavailability, a shift to a reductive pathway in dopamine and tyramine oxidative metabolism, and the biotransformation of Tyr to OHTyr were mechanisms involved in the OHTyr endogenous generation.     

四川省桶装饮用水铜绿假单胞菌污染情况调查及防控措施研究

目的查找四川省桶装饮用水企业生产过程中铜绿假单胞菌污染的关键风险点,分析污染原因并提出相应防控措施。方法选取四川省内10家包装饮用水生产企业,实地调研生产工艺,并在工艺各环节采集水样,按照GB 8538-2016《食品安全国家标准饮用天然矿泉水检验方法》中铜绿假单胞菌滤膜过滤法检测。结果现有水处理工艺能有效消除源水中的微生物污染,回收桶为引入铜绿假单胞菌污染的最大风险点,回收桶的清洗工艺至关重要。结论企业应从水源保护、水处理工艺、规范操作、生产和灌装环境、机器设备、包装材料、消毒剂合理使用、生产环节监控等8个方面制定合理的工艺流程、监控点、监控频次和监控指标,保障产品质量。