Monthly Archives: September 2015

Microbiological Evaluation of Electric Kettles; Rural China

Cohen A, Tao Y, Luo Q, Zhong G, Romm J, Colford JM Jr, Ray I. Microbiological Evaluation of Household Drinking Water Treatment in Rural China Shows Benefits of Electric Kettles: A Cross-Sectional Study. PloS one. 2015 Sep 30;10(9):e0138451. doi: 10.1371/journal.pone.0138451. 

BACKGROUND: In rural China ~607 million people drink boiled water, yet little is known about prevailing household water treatment (HWT) methods or their effectiveness. Boiling, the most common HWT method globally, is microbiologically effective, but household air pollution (HAP) from burning solid fuels causes cardiovascular and respiratory disease, and black carbon emissions exacerbate climate change. Boiled water is also easily re-contaminated. Our study was designed to identify the HWT methods used in rural China and to evaluate their effectiveness.

METHODS: We used a geographically stratified cross-sectional design in rural Guangxi Province to collect survey data from 450 households in the summer of 2013. Household drinking water samples were collected and assayed for Thermotolerant Coliforms (TTC), and physicochemical analyses were conducted for village drinking water sources. In the winter of 2013-2104, we surveyed 120 additional households and used remote sensors to corroborate self-reported boiling data.

FINDINGS: Our HWT prevalence estimates were: 27.1% boiling with electric kettles, 20.3% boiling with pots, 34.4% purchasing bottled water, and 18.2% drinking untreated water (for these analyses we treated bottled water as a HWT method). Households using electric kettles had the lowest concentrations of TTC (73% lower than households drinking untreated water). Multilevel mixed-effects regression analyses showed that electric kettles were associated with the largest Log10TTC reduction (-0.60, p<0.001), followed by bottled water (-0.45, p<0.001) and pots (-0.44, p<0.01). Compared to households drinking untreated water, electric kettle users also had the lowest risk of having TTC detected in their drinking water (risk ratio, RR = 0.49, 0.34-0.70, p<0.001), followed by bottled water users (RR = 0.70, 0.53-0.93, p<0.05) and households boiling with pots (RR = 0.74, 0.54-1.02, p = 0.06).

CONCLUSION: As far as we are aware, this is the first HWT-focused study in China, and the first to quantify the comparative advantage of boiling with electric kettles over pots. Our results suggest that electric kettles could be used to rapidly expand safe drinking water access and reduce HAP exposure in rural China.

UV Irradiation Effects Free Chlorine Consumption

Zhang TY, Lin YL, Xu B, Xia SJ, Tian FX, Gao NY. Effect of UV irradiation on the proportion of organic chloramines in total chlorine in subsequent chlorination. Chemosphere. 2015 Sep 29;144:940-947. doi: 10.1016/j.chemosphere.2015.09.074.

This study investigated the changes of chlorine species and proportion of organic chloramines during the chlorination process after UV irradiation pretreatment in drinking water. It was found that the UV pretreatment could enhance the percentage of organic chloramines by increasing free chlorine consumption in the chlorination of raw waters. The percentage of organic chloramines in total chlorine increased with UV intensity and irradiation time in raw waters. However, for the humic acid synthesized water, the percentage of organic chloramines increased first and then decreased with the increase of UV irradiation time. The value of SUVA declined in both raw and humic acid synthesized waters over the UV irradiation time, which indicated that the decomposition of aromatic organic matter by UV could be a contributor to the increase of free chlorine consumption and organic chloramine proportion. The percentage of organic chloramines during chlorination of raw waters after 30-min UV irradiation pretreatment varied from 20.2% to 41.8%. Total chlorine decreased obviously with the increase of nitrate concentration, but the percentage of organic chloramines increased and was linearly correlated to nitrate concentration.

Sea Level Dropping in Nain, Canada

Nain canada sea level
The mean sea level trend is -2.02 millimeters/year with a 95% confidence interval of +/- 0.74 mm/yr based on monthly mean sea level data from 1963 to 2010 which is equivalent to a change of -0.66 feet in 100 years.

Environmentalism Gone Mad

There is another side of the story.


Barnes and Noble:

In the mid-2000s he began researching the claims by the environmental movement and the UN that the release of carbon dioxide by modern civilization will lead to catastrophic global warming. This book is an account of his personal journey of discovery.

In Environmentalism Gone Mad, Dr. Carlin documents the dysfunction of the modern environmental movement-demonstrating the need of a major course correction to steer it back to reality.

Manganese Deposition in Drinking Water Distribution Systems

Gerke TL, Little BJ, Barry Maynard J. Manganese deposition in drinking water distribution systems. The Science of the total environment. 2015 Sep 23;541:184-193. doi: 10.1016/j.scitotenv.2015.09.054.

This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn3+ and Mn4+) and hollandite (Mn2+ and Mn4+), and a Mn silicate, braunite (Mn2+ and Mn4+), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality.

Reducing Pathogens in Combined Sewer Overflows

Tondera K, Klaer K, Gebhardt J, Wingender J, Koch C, Horstkott M, Strathmann M, Jurzik L, Hamza IA, Pinnekamp J. Reducing pathogens in combined sewer overflows using ozonation or UV irradiation. International journal of hygiene and environmental health. 2015 Sep 18. pii: S1438-4639(15)00119-4. doi: 10.1016/j.ijheh.2015.09.002.

Fecal contamination of water resources is a major public health concern in densely populated areas since these water bodies are used for drinking water production or recreational purposes. A main source of this contamination originates from combined sewer overflows (CSOs) in regions with combined sewer systems. Thus, the treatment of CSO discharges is urgent. In this study, we explored whether ozonation or UV irradiation can efficiently reduce pathogenic bacteria, viruses, and protozoan parasites in CSOs. Experiments were carried out in parallel settings at the outflow of a stormwater settling tank in the Ruhr area, Germany. The results showed that both techniques reduce most hygienically relevant bacteria, parasites and viruses. Under the conditions tested, ozonation yielded lower outflow values for the majority of the tested parameters.

Fluoride Adversely Affects Intelligence Quotient of 10 to 12 Year-olds?

Note that the “high” fluoride concentration in this study is only 2.2 mg/L.

Sebastian ST, Sunitha S. A cross-sectional study to assess the intelligence quotient (IQ) of school going children aged 10-12 years in villages of Mysore district, India with different fluoride levels. Journal of the Indian Society of Pedodontics and Preventive Dentistry. 2015 Oct-Dec;33(4):307-11. doi: 10.4103/0970-4388.165682.

INTRODUCTION: Besides dental and skeletal fluorosis, excessive fluoride intake can also affect the central nervous system without first causing the physical deformities associated with skeletal fluorosis. With the existence of widespread endemic fluorosis in India, the possible adverse effect of elevated fluoride in drinking water on the Intelligence Quotient (IQ) level of children is a potentially serious public health problem.

AIMS AND OBJECTIVES: This study assessed the Intelligence Quotient (IQ) of school going children aged 10-12 years in villages of Mysore district with different fluoride levels.

MATERIALS AND METHODS: In this cross-sectional study, 405 school children aged 10-12 years were selected from three villages in Mysore district with normal fluoride (1.20 mg F/l), low fluoride (0.40 mg F/l) and high fluoride (2.20 mg F/l) in their water supplies. A pre designed questionnaire was used to collect the required data for the survey which included socio demographic details, oral hygiene practices, diet history, body mass index and dental fluorosis. Intelligence Quotient was assessed using Raven’s colored Progressive Matrices Test.

RESULTS: In bivariate analysis, significant relationships were found between water fluoride levels and Intelligence Quotient of school children (P < 0.05). In the high fluoride village, the proportion of children with IQ below 90, i.e. below average IQ was larger compared to normal and low fluoride village. Age, gender, parent education level and family income had no significant association with IQ.

CONCLUSION: School children residing in area with higher than normal water fluoride level demonstrated more impaired development of intelligence when compared to school children residing in areas with normal and low water fluoride levels. Thus, children’s intelligence can be affected by high water fluoride levels.