Monthly Archives: November 2016

Nosocomial diarrhea outbreak, Chile

Coria P, Urízar C, Alba A, Noemí I, Pino A, Cerva JL. [The water supply of a pediatric hospital as a possible source of an outbreak of diarrhea due to Microsporidium spp. in immunocompromised patients] Rev Chilena Infectol. 2016 Aug;33(4):373-379. [Article in Spanish]

INTRODUCTION: The hospital water supply is a reservoir of a variety of potentially pathogenic microorganisms that can particularly affect children and immunocompromised patients. Potentially pathogenic Microsporidium spp. have been identified in water. Microsporidiosis is an emerging parasitic and opportunistic infection in immunocompromised patients.

OBJECTIVE AND METHOD: to describe an outbreak of nosocomial diarrhea due to Microsporidium, species Encephalitozoon intestinalis.

RESULTS: Seven cases of E. intestinalis associated diarrhea were reported between november 2012 and february 2013, in a unit of immunocompromised patients in L. Calvo Mackenna Children’s Hospital. Microsporidium spp. was found in the hospital water supply and water reservoir tank. Secondary cases were transmitted by contact. Control measures included contact precautions, not to use faucet water for hand washing, bottled water for drinking and water reservoir tank sanitation.

CONCLUSIONS: This research is about a nosocomial outbreak associated with water supply. Water quality in Chilean hospitals is an unresolved issue, especially in immunocompromised patient areas. Compliance of cleaning and disinfection of water supply systems in hospitals must be ensured.

Ground water transport model requires independent validation

Ground water transport models are relatively easy to develop if enough assumptions are made. Validation is needed before the output of any model is applied. Also, Pb-210 is a decay produce of radon and will be present in any water from an aquifer containing radium-226 or other radionuclides in its decay chain. This model must assume secular equilibrium.

Torres L, Yadav OP, Khan E. Holistic risk assessment of surface water contamination due to Pb-210 in oil produced water from the Bakken Shale. Chemosphere 2016 Nov 29;169:627-635. doi: 10.1016/j.chemosphere.2016.11.125.

A holistic risk assessment of surface water (SW) contamination due to lead-210 (Pb-210) in oil produced water (PW) from the Bakken Shale in North Dakota (ND) was conducted. Pb-210 is a relatively long-lived radionuclide and very mobile in water. Because of limited data on Pb-210, a simulation model was developed to determine its concentration based on its parent radium-226 and historical total dissolved solids levels in PW. Scenarios where PW spills could reach SW were analyzed by applying the four steps of the risk assessment process. These scenarios are: (1) storage tank overflow, (2) leakage in equipment, and (3) spills related to trucks used to transport PW. Furthermore, a survey was conducted in ND to quantify the risk perception of PW from different stakeholders. Findings from the study include a low probability of a PW spill reaching SW and simulated concentration of Pb-210 in drinking water higher than the recommended value established by the World Health Organization. Also, after including the results from the risk perception survey, the assessment indicates that the risk of contamination of the three scenarios evaluated is between medium-high to high.

Lead exposure and diabetes

Tyrrell JB, Hafida S, Stemmer P, Adhami A, Leff T. Lead (Pb) exposure promotes diabetes in obese rodents. J Trace Elem Med Biol. 2017 Jan;39:221-226. doi: 10.1016/j.jtemb.2016.10.007.

BACKGROUND: Pb (lead) exposure occurs at elevated frequency in urban inner city populations that also have high rates of obesity and diabetes.

OBJECTIVES: To determine if Pb can promote the development of diabetes in a setting of obesity, we examined the effect of Pb exposure on glucose metabolism in a rodent model of obesity.

METHODS: Adult female ZDF rats were exposed to Pb in drinking water for 24 weeks. Fasting blood glucose, insulin, and glucose tolerance were measured at regular intervals. Expression of hepatic gluconeogenic genes was measured in exposed and control animals and in cultured hepatoma cells treated with Pb.

RESULTS: Pb exposure induced fasting hyperglycemia after 8 weeks and glucose intolerance after 12 weeks of exposure. In addition, Pb-exposed animals showed elevated hepatic triglyceride levels and increased expression of the gluconeogenic genes PEPCK and glucose-6-phosphatase. In cultured rat hepatoma cells treatment with Pb stimulated PEPCK and glucose-6-phosphatase gene expression, suggesting a possible direct effect of Pb on hepatic gluconeogenic gene expression.

CONCLUSIONS: In the setting of obesity, Pb exposure is prodiabetic, causing fasting hyperglycemia and glucose intolerance in rats. A contributing factor to the metabolic effects of Pb may be the direct stimulation of hepatic gluconeogenic gene expression.

Uranium Exposure from Drinking Water, Rajasthan, India

Jakhu R, Mehra R, Mittal HM. Exposure assessment of natural uranium from drinking water. Environmental Science: Process Impacts. Nov 2016 

The uranium concentration in the drinking water of the residents of the Jaipur and Ajmer districts of Rajasthan has been measured for exposure assessment. The daily intake of uranium from the drinking water for the residents of the study area is found to vary from 0.4 to 123.9 μg per day. For the average uranium ingestion rate of 35.2 μg per day for a long term exposure period of 60 years, estimations have been made for the retention of uranium in different body organs and its excretion with time using ICRP’s biokinetic model of uranium. Radioactive and chemical toxicity of uranium has been reported and discussed in detail in the present manuscript.

Human Health Risk Associated with Perfluorinated Carboxylates (PFCAs)

Rand AA, Mabury SA. Is there a human health risk associated with indirect exposure to perfluorinated carboxylates (PFCAs)? Toxicology. 2016 Nov 19. pii: S0300-483X(16)30281-5. doi: 10.1016/j.tox.2016.11.011.

The production and widespread use of poly- and perfluorinated alkyl substances (PFAS) has led to their presence in environment, wildlife, and humans. Particularly, the perfluorinated carboxylates (PFCAs) are pervasive throughout the world and have been found at ng/mL concentrations in human blood. PFCAs, especially those having longer carbon chain lengths (≥C6), are associated with developmental and hormonal effects, immunotoxicity, and promote tumor growth in rodents through their role as PPARα agonists. Humans are directly exposed to PFCAs primarily through contaminated food, drinking water, and house dust. However, indirect exposure to PFCAs through the biotransformation of fluorotelomer-based substances may also be a significant, yet relatively underappreciated pathway. We are exposed to fluorotelomer-based substances through use of consumer products, ingestion of food, or from inhalation of dust particles, but the risk of this exposure has been largely uncharacterized. Here, we summarize the work that has been done to characterize toxicity of the classes of fluorotelomer-based substances shown to biotransform to PFCAs: the polyfluoroalkyl phosphate esters (PAPs), fluorotelomer alcohols (FTOHs), fluorotelomer iodides (FTIs), and fluorotelomer acrylate monomers (FTAcs). These fluorotelomer-based substances biotranform to yield PFCAs, yet also form bioactive intermediate metabolites, which have been observed to be more toxic than their corresponding PFCAs. We address what is known regarding the toxicity of the fluorotelomer-based substances and their metabolites, with focus on covalent binding to biological nucleophiles, such as glutathione, proteins, and DNA, as a possible mechanism of toxicity that may influence the risk of indirect exposure to PFCAs.

Photochemical Decomposition of perfluororcarboxylic acids (PFCAs)

Qu R, Liu J, Li C, Wang L, Wang Z, Wu J. Experimental and theoretical insights into the photochemical decomposition of environmentally persistent perfluorocarboxylic acids. Water Research. 2016 Nov 1;104:34-43. doi: 10.1016/j.watres.2016.07.071.

Decomposition of perfluorocarboxylic acids (PFCAs) is of great significance due to their global distribution, persistence and toxicity to organisms. In this study, the photodegradation of a series of PFCAs (∼C2C12) in water by a medium-pressure mercury lamp was experimentally and theoretically examined. We found that photolysis of PFCAs all follow pseudo-first-order kinetics with the rate constant (kapp) increasing with carbon chain lengths, except for trifluoroacetic acid (TFA) which cannot be degraded by the polychromatic irradiation. Product analysis showed that the PFCAs were mainly decomposed into shorter carbon chain length PFCAs in a stepwise manner, with the accumulation of TFA and fluoride ions as the end products. Moreover, a small amount of perfluoroolefins (CnF2n) was determined as gas-phase products. Wiberg bond order calculations confirmed the cleavage of the CC bond between carboxylic carbon and the adjacent carbon as the first reaction step, and density functional theory-based calculations revealed that kapp value is correlated with some molecular structural parameters. In the case of mixture irradiation, the evolution profiles of individual PFCAs were different from that in single-component systems, due to the dynamic balance between production and degradation. This work reveals the main molecular descriptors controlling the degradation rate of different PFCAs species, and improves the general understanding on the photodegradation mechanisms, which will provide useful information for future researches.

How to Create Global Warming by Adjusting the Data

NASA shows us how:


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