Kao PM, Hsu BM, Hsu TK, Liu JH, Chang HY, Ji WT, Tzeng KJ, Huang SW, Huang YL. Seasonal distribution of potentially pathogenic Acanthamoeba species from drinking water reservoirs in Taiwan. Environ Sci Pollut Res Int. 2014 Sep 30.
In order to detect the presence/absence of Acanthamoeba along with geographical variations, water quality variations and seasonal change of Acanthamoeba in Taiwan was investigated by 18S ribosomal RNA (rRNA) gene TaqMan quantitative real-time PCR. Samples were collected quarterly at 19 drinking water reservoir sites from November 2012 to August 2013. Acanthamoeba was detected in 39.5 % (30/76) of the water sample, and the detection rate was 63.2 % (12/19) from samples collected in autumn. The average concentration of Acanthamoeba was 3.59 × 104 copies/L. For geographic distribution, the detection rate for Acanthamoeba at the northern region was higher than the central and southern regions in all seasons. Results of Spearman rank test revealed that heterotrophic plate count (HPC) had a negative correlation (R = -0.502), while dissolved oxygen (DO) had a positive correlation (R = 0.463) in summer. Significant differences were found only between the presence/absence of Acanthamoeba and HPC in summer (Mann-Whitney U test, P < 0.05). T2 and T4 genotypes of Acanthamoeba were identified, and T4 was the most commonly identified Acanthamoeba genotypes. The presence of Acanthamoeba in reservoirs presented a potential public health threat and should be further examined.
Kaplan DI, Denham ME, Zhang S, Yeager C, Xu C, Schwehr KA, Li HP, Ho YF, Wellman D, Santschi PH. Radioiodine Biogeochemistry and Prevalence in Groundwater. Crit Rev Environ Sci Technol. 2014 Oct 18;44(20):2287-2335.
129I is commonly either the top or among the top risk drivers, along with 99Tc, at radiological waste disposal sites and contaminated groundwater sites where nuclear material fabrication or reprocessing has occurred. The risk stems largely from 129I having a high toxicity, a high bioaccumulation factor (90% of all the body’s iodine concentrates in the thyroid), a high inventory at source terms (due to its high fission yield), an extremely long half-life (16M years), and rapid mobility in the subsurface environment. Another important reason that 129I is a key risk driver is that there is uncertainty regarding its biogeochemical fate and transport in the environment. We typically can define 129I mass balance and flux at sites, but cannot predict accurately its response to changes in the environment. As a consequence of some of these characteristics, 129I has a very low drinking water standard, which is set at 1 pCi/L, the lowest of all radionuclides in the Federal Register. Recently, significant advancements have been made in detecting iodine species at ambient groundwater concentrations, defining the nature of the organic matter and iodine bond, and quantifying the role of naturally occurring sediment microbes to promote iodine oxidation and reduction. These recent studies have led to a more mechanistic understanding of radioiodine biogeochemistry. The objective of this review is to describe these advances and to provide a state of the science of radioiodine biogeochemistry relevant to its fate and transport in the terrestrial environment and provide information useful for making decisions regarding the stewardship and remediation of 129I contaminated sites. As part of this review, knowledge gaps were identified that would significantly advance the goals of basic and applied research programs for accelerating 129I environmental remediation and reducing uncertainty associated with disposal of 129I waste. Together the information gained from addressing these knowledge gaps will not alter the observation that 129I is primarily mobile, but it will likely permit demonstration that the entire 129I pool in the source term is not moving at the same rate and some may be tightly bound to the sediment, thereby smearing the modeled 129I peak and reducing maximum calculated risk.
Everyone involved in research wants to be the first to discover something. The pressure is so great especially at research universities where students typically never get to see their professors outside of class. Once someone thinks they have discovered something for the first time they want it published as soon as possible in a “peer-reviewed paper. That’s what is expected by the University Administration. It’s how academicians at research universities keep their job and eventually get tenure.
Open-peer review before publication sounds good and would help to prevent premature announcements of scientific findings that are later proved incorrect (as discussed in the article cited below).
However, there is a danger. Having had research “ideas” stolen by other professors at a public institution I can certainly say it does happen. Would “open peer review” encourage this? I tell students that in academia “Everyone is operating out of different rule books.” And because of this research ideas (and associated data) are a precious commodity that researchers must learn to protect, even if they end up being incorrect. Otherwise, they won’t be doing research for very long.
“The team involved has been criticised for publishing results before they were peer reviewed. But this is what science is: debate, discussion, deliberation.” click here for news article
Konietzka R. Gastrointestinal absorption of uranium compounds – a review. Regul Toxicol Pharmacol. 2014 Sep 25. pii: S0273-2300(14)00192-5. doi: 10.1016/j.yrtph.2014.08.012.
Uranium occurs naturally in soil and rocks, and therefore where it is present in water-soluble form it also occurs naturally in groundwater as well as in drinking water obtained from groundwater. Animal studies suggest that the toxicity of uranium is mainly due to its damage to kidney tubular cells following exposure to soluble uranium compounds. The assessments of the absorption of uranium via the gastrointestinal tract vary, and this has consequences for regulation, in particular the derivation of e. g. drinking water limit values. Absorption rates vary according to the nature and solubility of the compound in which uranium is presented to the test animals and depending on the animal species used in the test. No differences for sex have been observed for absorption in either animals or humans. However, human biomonitoring data do show that boys excrete significantly more uranium than girls. In animal studies neonates took up more uranium than adults or older children. Nutritional status, and in particular the iron content of the diet, have a marked influence on absorption, and higher uranium levels in food intake also appear to increase the absorption rate. If the pointers to an absorption mechanism competing with iron are correct, these mechanisms could also explain the relatively high concentration and chemical toxicity of uranium in the kidneys. It is here (and in the duodenum) that divalent metal transporter 1 (DMT1), which is primarily responsible for the passage of iron (or uranium?) through the cell membranes, is most strongly expressed.
Reason enough to vote democrats out of congress (House and Senate). Click here
“Gobal warming contributed to extreme heat waves in many arts of the world last year, but cannot be definitively linked to the California drought, according to a report released Monday.”
“The third annual analysis of extreme weather events underscored the continuing difficulty of teasing out the influence of human-caused climate change on precipitation patterns.” click here
Posted in Climate
“An Associated Press fact-check on President Obama’s climate change speech to the United Nations Tuesday accused the president of clearly spinning the facts and distorting the truth about America’s response to global warming.” click here