Monthly Archives: October 2014

Volcanic Aerosols Have Minor Role in Recent Global Temperature Plateau

The absence of any major volcanic eruptions post-2000 raises some serious questions regarding the results of this study. One simply cannot look only at one ‘part” or factor (e.g. particles) at a time in atmospheric chemistry and physics and expect the results to represent  the “whole.” 

Gödel’s incompleteness theorems suggest that no matter how much climate mathematical modeling one does of the parts, it cannot reproduce the “whole.” The “whole” is always much more than what the sum of the “parts” suggest. And in this case the global climate is much, much more than what any mathematical modeling of any part of it (e.g. volcanic particles) suggest, and always will be. Observational science gives us an indication of the physical state of the “whole.” Mathematical modeling cannot do this. And this is why observational science should be preferred and supplemented with modeling rather than the other way around (where modeling is primarily considered).

Lastly, I am always bewildered when I see a paper (or in this case a letter) loaded with coauthors (or signatories), in this case 16. It leaves me with the impression of scientific bullying – the paper with the most coauthors must be the correct one (or perhaps just the politically correct one). But the number of coauthors is irrelevant to the validity of the analysis and likely says more about “group think” dynamics than anything to do with the science itself.

D.A Ridley, S. Solomon, J. E. Barnes, V.D. Burlakov, T. Deshler, S.I. Dolgii, T. Nagai, R.R. Neely III, A.V. Nevzorov, C. Ritter, T. Sakai, B.D. Santer, M. Sato, A. Schmidt, O. Uchino and J. P. Vernier. Total volcanic stratospheric aerosol optical depths and implications for global climate change. Geophysical Research Letters. DOI: 10.1002/2014GL061541

Click here for full paper (fee).

 

Hardness Enhances Virus Survival in High Turbidity Waters?

Turbidity and suspended solids can provide protection of microorganisms against disinfectants and environmental stress. This study suggests hardness plays a role although the experimental conditions were limited.

[Effects of algae and kaolinite particles on the survival of bacteriophage MS2]

He Q, Wu QQ, Ma HF, Zhou ZM, Yuan BL. [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui “Huan jing ke xue” bian ji wei yuan hui.].” Huan Jing Ke Xue. 2014 Aug;35(8):3192-7. Article in Chinese.

In this study, Bacteriophage MS2, Kaolinite and Microcystis aeruginosa were selected as model materials for human enteric viruses, inorganic and organic particles, respectively. The influence of the inorganic (Kaolinite) or organic (Microcystis aeruginosa) particles on the survival of MS2 at different conditions, such as particles concentration, pH, ion concentration and natural organic matter (NOM) were studied. The results showed that Kaolinite had no effect on the survival of phage MS2 except that apparent survival of MS2 increased 1 logarithm in higher hardness water. Microcystis aeruginosa addition reduced 1 logarithm of MS2 survival. However, when the pH value was greater than 4.0 or the concentration of Microcystis aeruginosa was less than 1.0 x 10(6) cells x L(-1), Microcystis aeruginosa addition had no influence on the survival of MS2. In higher hardness water, Microcystis aeruginosa protected MS2 viruses and then increased the survival of MS2. In drinking water, resource containing higher concentration of particles, the survival ability of virus would be enhanced with the increase of the hardness and then elevated the risks of drinking water safety.

Chlorella sorokiniana slows biological denitrification

Petrovič A, Simonič M. Effect of Chlorella sorokiniana on the biological denitrification of drinking water. Environmental science and pollution research international. 2014 Oct 28.

The influence of Chlorella sorokiniana on drinking water’s biological denitrification was studied at two different initial nitrate concentrations, 50 and 100 mg/L, respectively. Sucrose and grape juice were used as carbon sources. The experiments showed that the denitrification process in the presence of algae was, even at low concentrations, i.e. 50 mg/L of nitrate, slower than without them, but yet still more than 95 % of nitrate was removed in 24 h. It was also discovered that, with the addition of ammonium and urea, the urea interfered much more with the denitrification process, as less than 50 % of the initial nitrate was removed. However, algae did not contribute to the nitrate and ammonium removals, as the final concentrations of both in the presence of algae were higher by approx 5 %. At 100 mg/L of initial nitrate, the denitrification kinetics in the presence of algae was apparently slower regarding those experiments at lower levels of nitrate and only 65-70 % of nitrate was removed over 24 h. Using grape juice instead of sucrose improved the nitrate removal slightly.

Click here for paper (fee).

Evaluation of Fluoride, Herbal Toothpastes Against Streptococcus mutans

Randall J, Seow W, Walsh L. Antibacterial activity of fluoride compounds and herbal toothpastes on Streptococcus mutans: An in vitro study. Australian dental journal. 2014 Oct 27. doi: 10.1111/adj.12247.

BACKGROUND: Streptococcus mutans is an important bacterial species implicated in dental caries. This laboratory study compared the antimicrobial activity of a number of fluoride-containing and herbal dentifrices and their components against S. mutans.

METHODS: An agar diffusion method was used with Mueller-Hinton agar. Wells were filled with either 10 commercial fluoride or 6 herbal dentifrices, or with solutions of various fluoride compounds, sodium lauryl sulphate, sodium benzoate, chlorhexidine digluconate or triclosan. Diameters of zones of bacterial growth inhibition surrounding the wells were measured using a micrometer.

RESULTS: Significant differences were found for growth inhibition between the 10 fluoridated dentifrices (P<0.0001), with Colgate Total having the greatest effect. There was not a direct correlation with fluoride type or fluoride concentration. The antibacterial activities of the 6 herbal toothpastes varied, with Herbal Fresh being the strongest. Sodium lauryl sulphate showed strong antimicrobial activity against S. mutans at the levels used in dentifrices.

CONCLUSIONS: Antimicrobial activity of commercial dentifrices against S. mutans may be exerted by components other than fluoride. Ingredients such as triclosan and sodium lauryl sulphate have larger antimicrobial effects than fluorides in this model.

Click here for full paper (fee).

 

CDC Finally Admits Ebola Potentially Transmitted Through Sneezing

“Ebola is a lot easier to catch than health officials have admitted — and can be contracted by contact with a doorknob contaminated by a sneeze from an infected person an hour or more before, experts told The Post Tuesday.” click here

Radon in Beijing City Drinking Water

Wu YY, Ma YZ, Cui HX, Liu JX, Sun YR, Shang B, Su X Radon concentrations in drinking water in beijing city, china and contribution to radiation dose. International journal of environmental research and public health. 2014 Oct 27;11(11):11121-31. doi: 10.3390/ijerph111111121.

222Rn concentrations in drinking water samples from Beijing City, China, were determined based on a simple method for the continuous monitoring of radon using a radon-in-air monitor coupled to an air-water exchanger. A total of 89 water samples were sampled and analyzed for their 222Rn content. The observed radon levels ranged from detection limit up to 49 Bq/L. The calculated arithmetic and geometric means of radon concentrations in all measured samples were equal to 5.87 and 4.63 Bq/L, respectively. The average annual effective dose from ingestion of radon in drinking water was 2.78 μSv, and that of inhalation of water-borne radon was 28.5 μSv. It is concluded that it is not the ingestion of waterborne radon, but inhalation of the radon escaping from water that is a substantial part of the radiological hazard. Radon in water is a big concern for public health, especially for consumers who directly use well water with very high radon concentration.

Click here for paper (Open Access).

Colorado Arsenic Study Looks Impressive, but is it True?

Back in the days when drinking water epidemiology studies were useful, this type of study would not have gotten off the ground because exposure is not directly measured. Why is this important? Because if enough assumptions are made using computer models an association can be found just about anywhere between anything. And that looks to be what has happened here. These authors in many respects have simply ended up assuming their way to the desired conclusion without realizing it. Having said that, it is reasonable to expect arsenic exposure to have a role in CHD and the Alamosa area is known for high ground water arsenic concentrations. (The town of Alamosa now has treatment for arsenic removal.) At issue is whether there is an effect at concentrations below 50 ug/L (the old limit) or even 10 ug/L (the new standard). As with the Alan Smith internal cancer study in 1991, advocates will grab on to this study to make alarming political statements.

As a side note, whether funding was provided for the study (and if so from who) really has no role in defining the credibility of the study. The authors state they were not financially supported. But this is irrelevant. Of most importance are the assumptions behind the analysis many of which are unstated. And of course, if they are employed someone pays them for their work. A lot of work went into this study and some aspects are useful. The weakness is in the underlying data, analysis and interpretation. Data and analysis are not neutral. The presuppositions and assumptions of the researchers define the outcome.

Finally, EHP is government funded and run publication that generally publishes papers from a particular point of view regardless of the strength of the study.

James KA, Byers T, Hokanson JE, Meliker JR, Zerbe GO, Marshall JA. Association between Lifetime Exposure to Inorganic Arsenic in Drinking Water and Coronary Heart Disease in Colorado Residents. Environ Health Perspect. 2014 Oct 28.

BACKGROUND: Chronic diseases, including coronary heart disease, have been associated with ingestion of drinking water with high levels of inorganic arsenic (over 1000 μg/L). However, associations have been inconclusive in populations with lower levels (<100 μg/L) of inorganic arsenic exposure.

OBJECTIVES: We conducted a case-cohort study based on individual estimates of lifetime arsenic exposure to examine the relationship between chronic low-level arsenic exposure and risk of CHD.

METHODS: This study included 555 participants with 96 CHD events diagnosed between 1984 and 1998 for which individual lifetime arsenic exposure estimates were determined using data from structured interviews and secondary data sources to determine lifetime residence which was linked to a, geospatial model of arsenic concentrations in drinking water, which were correlated with historically collected urinary arsenic concentrations. A Cox proportional hazards model with time-dependent CHD risk factors was used to assess the association between lifetime exposure to low-level inorganic arsenic in drinking water and incident CHD.

RESULTS: We estimated a positive association between low-level inorganic arsenic exposure and CHD risk (Hazard Ratio (HR): =1.38, 95%=1.09 1.78 per 15 μg/L) while adjusting for age, gender, first-degree family history of CHD, and serum low density lipoprotein levels. The risk of CHD increased monotonically with increasing TWAs for inorganic arsenic exposure in water relative to < 20 μg/L (HR=1.2; 95% CI: 0.6, 2.2 for 20-30 μg/L, HR=2.2; 95% CI: 1.2, 4.0 for 30-45 μg/L, and HR=3; 95% CI: 1.1, 9.1 for 45-88 μg/L).

CONCLUSIONS: Lifetime exposure to low-level inorganic arsenic in drinking water was associated with increased risk for CHD in this population.

The study is here.