Nitzsche KS, Lan VM, Trang PT, Viet PH, Berg M, Voegelin A, Planer-Friedrich B, Zahoransky J, Müller SK, Byrne JM, Schröder C, Behrens S, Kappler A. Arsenic removal from drinking water by a household sand filter in Vietnam – Effect of filter usage practices on arsenic removal efficiency and microbiological water quality. Sci Total Environ. 2014 Oct 6;502C:526-536. doi: 10.1016/j.scitotenv.2014.09.055.
Household sand filters are applied to treat arsenic- and iron-containing anoxic groundwater that is used as drinking water in rural areas of North Vietnam. These filters immobilize poisonous arsenic (As) via co-oxidation with Fe(II) and sorption to or co-precipitation with the formed Fe(III) (oxyhydr)oxides. However, information is lacking regarding the effect of the frequency and duration of filter use as well as of filter sand replacement on the residual As concentrations in the filtered water and on the presence of potentially pathogenic bacteria in the filtered and stored water. We therefore scrutinized a household sand filter with respect to As removal efficiency and the presence of fecal indicator bacteria in treated water as a function of filter operation before and after sand replacement. Quantification of As in the filtered water showed that periods of intense daily use followed by periods of non-use and even sand replacement did not significantly (p<0.05) affect As removal efficiency. The As concentration was reduced during filtration from 115.1±3.4μgL-1 in the groundwater to 5.3±0.7μgL-1 in the filtered water (95% removal). The first flush of water from the filter contained As concentrations below the drinking water limit and suggests that this water can be used without risk for human health. Colony forming units (CFUs) of coliform bacteria increased during filtration and storage from 5±4 per 100mL in the groundwater to 5.1±1.5×103 and 15±1.4×103 per 100mL in the filtered water and in the water from the storage tank, respectively. After filter sand replacement, CFUs of Escherichia coli of <100 per 100 mL were quantified. None of the samples contained CFUs of Enterococcus spp. No critical enrichment of fecal indicator bacteria belonging to E. coli or Enterococcus spp. was observed in the treated drinking water by qPCR targeting the 23S rRNA gene. The results demonstrate the efficient and reliable performance of household sand filters regarding As removal, but indicate a potential risk for human health arising from the enrichment of coliform bacteria during filtration and from E. coli cells that are introduced by sand replacement.
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Changes in climate do indeed occur. But for the military to focus on an ambiguous climate change is to march in circles. This is akin to asking NASA to focus on stopping “solar system change”.
“At a meeting that brings together many of the world’s foremost military leaders, Defense Secretary Chuck Hagel is expected to reveal how the ongoing effects of global climate change pose an urgent risk to national security and require extensive rethinking of many aspects of the U.S. military.” click here
Dunn G, Bakker K, Harris L. Drinking Water Quality Guidelines across Canadian provinces and territories: jurisdictional variation in the context of decentralized water governance. International Journal Of Environmental Research And Public Health 2014 Apr 25; Vol. 11 (5), 4634-51.
This article presents the first comprehensive review and analysis of the uptake of the Canadian Drinking Water Quality Guidelines (CDWQG) across Canada’s 13 provinces and territories. This review is significant given that Canada’s approach to drinking water governance is: (i) highly decentralized and (ii) discretionary. Canada is (along with Australia) only one of two Organization for Economic Cooperation and Development (OECD) member states that does not comply with the World Health Organization’s (WHO) recommendation that all countries have national, legally binding drinking water quality standards. Our review identifies key differences in the regulatory approaches to drinking water quality across Canada’s 13 jurisdictions. Only 16 of the 94 CDWQG are consistently applied across all 13 jurisdictions; five jurisdictions use voluntary guidelines, whereas eight use mandatory standards. The analysis explores three questions of central importance for water managers and public health officials: (i) should standards be uniform or variable; (ii) should compliance be voluntary or legally binding; and (iii) should regulation and oversight be harmonized or delegated? We conclude with recommendations for further research, with particular reference to the relevance of our findings given the high degree of variability in drinking water management and oversight capacity between urban and rural areas in Canada.
“The misuse of specialized methods and procedures is a fundamental problem caused by climatology being a generalist discipline. Most are specialists in a single component, who then, inappropriately, call themselves climate scientists. When they try to link pieces of the massive system together, they invariably have to use unfamiliar techniques and procedures. The chance of error is high. It is most problematic for computer modelers.”
Click here for the full article by Dr. Tim Ball.