aelb conference today about tol, page-3

yes,

the University of Malaysia also had their conference today... far less helpful for Lynas.

From the SLSM facebook page:


first hand summary on the talk held in UM today.

*based on my memory. not words to words of what was said.
*to avoid trouble of legal threatening, some contents will be written in not so specific way.

1st Talk: Prof Chan.

1. What is being measured?
- During the process of Thorium-232 decay, alpha and beta(-) radiation will be emitted. the strong ionizing gamma radiation is emitted in very little amount.
- Radiation from gamma particle in irrelevant to the issue, although we cannot totally exclude it.
- When we talk about level of radiation and harm, what is actually being measured? alpha, beta (-) or gamma? you cannot use a gamma dosimeter to assess the risk of exposure to radiation from alpha particle, right?

2. The concern of internal emitters
- Major concern of emission of radiation from rare earth processing plant on health risk is from the alpha particle.
- This is because from point of view of health risk on our issue here, alpha particle has the potential to do more damage
- External exposure to alpha particle cause little harm, as it is very weak and can be absorbed by few inches of air or a piece of paper. you won't be able to measure any radiation from alpha particle from a material contained inside a glass vial, it is absorbed by the glass.
- Concern is the potential of having ingested or inhaled, giving to internal emitter of alpha particle
- Following inverse square law, if the distance of alpha particle emitter to human decrease from meter scale (external) to micrometer scale (internal), the intensity of radiation the cell receive increase 1 trillion folds. (!)
- Dosimetry at micrometer scale from internal emitter should be taken into consideration and assessed. We are talking about radiation damage at cellular and sub-cellular level.
- Sub-cellular level damage, as for other more dangerous element, can bind the DNA, emitting at angstrom scale, further bring the damage a few magnitude of order higher.
- When dealing with health risk, the bio-kinetics inside the body must be emphasized. How it is taken into body, where do it go, how long the retention is and how it is excreted. Because Thorium 232 is bone seeking and deposit in bone marrow, that's why we see cases of leukemia.

3.What standard?
- Our quantitative risk model are mostly from empirical data on intense external gamma radiation exposure. Science are still pretty unclear about chronic and low dose exposure.
- There are different schools of hypotheses to the effects on low dose exposure effect: harmless, or adverse at long term, or even beneficial.
- Studies at national level by the German and French officials using robust statistical design have shown that exposure to low level of radiation at levels of 2-3 order of magnitude (100-1000 times) under 'safety level' can also increase the risk of getting childhood leukemia to those live near to the nuclear power plant.
- There is certainly an uncertainty on the effect of low dose exposure from view of science.
- National Academy of Science adopt Linear No-Threshold Model (LNT). the dose-response curve do not assume any threshold to separate dose of no-effect and dose of harmless effect.
- This is to say: There is no 'safe dose' (threshold) of radiation. All have effects, from extremely small to extremely large.
- Because of this, there is no consensus on 'safe threshold', and any kind of such standard are subjected to challenge. Experts on this don't agree among themselves. When this kind of uncertainty happens, it is best to take precautionary approach.

** I think journalists will write reports later.
** The scientific papers and resources mentioned in this talk can be obtained from Prof Chan's department website in days of time.