Monthly Archives: January 2016

Risk Assessment of Arsenic in Groundwater, Southern Taiwan

Liang CP, Wang SW, Kao YH, Chen JS. Health risk assessment of groundwater arsenic pollution in southern Taiwan. Environmental Geochemistry and Health. 2016 Jan 27.

Residents of the Pingtung Plain, Taiwan, use groundwater for drinking. However, monitoring results showed that a considerable portion of groundwater has an As concentration higher than the safe drinking water regulation of 10 μg/L. Considering residents of the Pingtung Plain continue to use groundwater for drinking, this study attempted to evaluate the exposure and health risk from drinking groundwater. The health risk from drinking groundwater was evaluated based on the hazard quotient (HQ) and target risk (TR) established by the US Environmental Protection Agency. The results showed that the 95th percentile of HQ exceeded 1 and TR was above the safe value of threshold value of 10-6. To illustrate significant variability of the drinking water consumption rate and body weight of each individual, health risk assessments were also performed using a spectrum of daily water intake rate and body weight to reasonably and conservatively assess the exposure and health risk for the specific subgroups of population of the Pingtung Plain. The assessment results showed that 0.01-7.50 % of the population’s HQ levels are higher than 1 and as much as 77.7-93.3 % of the population being in high cancer risk category and having a TR value >10-6. The TR estimation results implied that groundwater use for drinking purpose places people at risk of As exposure. The government must make great efforts to provide safe drinking water for residents of the Pingtung Plain.

Enamel Fluoride Content Associated with Fluorosis Severity

Martinez-Mier EA, Shone DB, Buckley CM, Ando M, Lippert F, Soto-Rojas AE. Relationship between enamel fluorosis severity and fluoride content. Journal of Dentistry. 2016 Jan 22. pii: S0300-5712(16)30007-0. doi: 10.1016/j.jdent.2016.01.007.

OBJECTIVES: Enamel fluorosis is a hypomineralization caused by chronic exposure to high levels of fluoride during tooth development. Previous research on the relationship between enamel fluoride content and fluorosis severity has been equivocal. The current study aimed at comparing visually and histologically assessed fluorosis severity with enamel fluoride content.

METHODS: Extracted teeth (n=112) were visually examined using the Thylstrup and Fejerskov Index for fluorosis. Eruption status of each tooth was noted. Teeth were cut into 100μm slices to assess histological changes with polarized light microscopy. Teeth were categorized as sound, mild, moderate, or severe fluorosis, visually and histologically. They were cut into squares (2×2mm) for the determination of fluoride content (microbiopsy) at depths of 30, 60 and 90μm from the external surface.

RESULTS: Erupted teeth with severe fluorosis had significantly greater mean fluoride content at 30, 60 and 90μm than sound teeth. Unerupted teeth with mild, moderate and severe fluorosis had significantly greater mean fluoride content than sound teeth at 30μm; unerupted teeth with mild and severe fluorosis had significantly greater mean fluoride content than sound teeth at 60μm, while only unerupted teeth severe fluorosis had significantly greater mean fluoride content than sound teeth at 90μm.

CONCLUSIONS: Both erupted and unerupted severely fluorosed teeth presented higher mean enamel fluoride content than sound teeth.

CLINICAL SIGNIFICANCE: Data on fluoride content in enamel will further our understanding of its biological characteristics which play a role in the management of hard tissue diseases and conditions.

Mr. Ben Carson on America’s “Values and Laws”

NOAA Must Release Data (or Funding Should be Cut)

Public availability of data collected by any US government agency (e.g. EPA, NOAA, etc) is necessary for scientific accountability and to ensure data quality and objectivity, especially with regard to  statistical information.

Mann et al 2016 Time Series Analysis Flawed?

Two views on the paper by Mann et al 2016, The Likelihood of Recent Record Warmth, published in Nature.

The author’s view here which is the original paper.

And a statistician’s view here:

“I am anxious people understand that Mann’s errors are in no way unique or rare; indeed, they are banal and ubiquitous. I therefore hope this article serves as a primer in how not to analyze time series.”

In one sense Mr. Briggs has indirectly (but correctly) raised a problem which I have mentioned many times in the past on this blog, the problem of induction. More simply put, can we assume that the future will be like the past? The answer? No. (No less than Philosophers David Hume and Bertrand Russell made note of this fact decades ago.)

Mr. Barack Obama Pushes Across the “Separation of Powers” Line on Immigration

In 1989 I was sitting in a Washington DC Senate Hearing room next to a legislative director who informed me that “in this town you do what you want until somebody stops you.” This is exactly how the Obama Administration has operated. People of integrity do not behave this way.

But the Obama Administration makes it own rules, in this case by changing immigration law without Congress.

“A three-judge panel of U.S. Court of Appeals for the Fifth Circuit ruled against President Barack Obama’s amnesty with a late Monday decision that will probably last until after Obama leaves office on Jan. 20, 2017.” click here

The Supreme Court is going to hear this case (here). But this branch of government has become politicized as well. It appears to be only too willing to cut congress out as well to interpret the law as it pleases.

Two-State Solution for Arab-Israel Conflict Not Viable

Like it or not, US security is directly tied to Israel. The Obama Administration continues to push in the wrong direction when it comes to a “two-state solution.” Indeed, the Obama Administration is the most anti-Israel administration in history (click here).

“For many Americans claiming to be friends of Israel, belief in the two-state solution to the conflict with the Palestinians is more a matter of faith than anything else.click here for complete commentary.