Q. What do you think an individual can do in terms of saving themselves from the toxic effects keeping in mind that fishing is their living? As the Japan government didn't do much for a long time for the common people. 
A. The simple answer is to avoid eating and drinking things that may be contaminated.  But, as you learned from Paracelsus, dose matters.   We ingest minuscule quantities of many things that are harmful in large doses. 

Q. Question 9 of Quiz 1: Contaminants in water are often expressed as mg/L. That is mg of contaminant per: 
The correct answer was- liter of contaminated water (solution) But why it is not liter of water? When you were explaining the same thing in the material, its written that we add few grams of arsenic in a beaker and then pour water until it becomes 1 liter. Now this solution will be arsenic contaminated. I find the answer statement and the course material statement contradictory. Can you please help me out with this. I don't know if I've cleared my point or not.
A. Think of it if you added 500 gm of the arsenic.  Then fill to the one liter mark.  Clearly there is not one liter of water.  It is one liter of water plus contaminant. 

Q. Of what use/purpose is LC10?  Is it used by OSHA to define or regulate anything?
A. One could compare LC10s as well as LC50s, it’s just that LC50 is a common standard of comparison.  OSHA deals with human health and never uses those.  EPA and others deal with environmental effects and I have seen LC5 used as a maximum permitted in a discharge.  In humans, no deaths or harms is the standard, while in environmental effects, some deaths or harms might be acceptable, since natural systems recover.

Q. In reference to the Wetterhahn article:  The response from the department head at the time was "We're trying to urge the chemical community to establish a safer substitute for use as a standard."
Is there now a substitute for dimethyl mercury when studying the health effects of heavy metals on living organisms?  Or, is the solution PPE as referenced in the article?
A. Simple methyl mercury is a common environmental contaminant and the chemical that did the harm in Minamata.   Dimethyl-mercury is not found in the natural environment.  Whatever you were testing, you would want to be specific.  As we’ll learn later, PPE is always a last resort.  The first choice is to eliminate the hazard – don’t use dimethyl mercury for anything.  Of course you would need care that what you find for a substitute is not worse. 

Q. One question would be how you define a "hazardous substance"? I work for [an environmenal agency], and we regulate reporting for spills of oil and hazardous substances. Any release of a "hazardous substance" requires the responsible party to immediately notify us, but I have never seen a logic definition of a "hazardous substance". As you wrote in submodule 1F: "all substances can be poisons in excessive amounts".
A. I’ll give you one way in Module 2 – see if it is on a “list.”

Q. Doesn’t the NOEL definition leave room for differences based on method of observation? While I may not observe the fish swimming upside down visually as a result of contamination, how does the NOEL definition change if a more detailed observation method shows an effect I could not have observed without instrument aid?
A. Yes, when stating a NOEL or similar observation, the methods must be stated.  That is one reason why death is often the “end point” used Other than death, responses may be a continuum.    Also, that is why many agencies publish standard testing protocols – so results can be compared.