Questions and Answers of general interest to the class, that all students should be familiar with, are indicated with *** are are first in the queue:

***Q. The do-nothing alternative is characterized as the baseline risk assessment.   Does this mean that is does not require a risk assessment?   The wording on the laws are a bit confusing.  
A. “Do nothing” is a risk management option.  The baseline risk assessment is the risk assessment before you do anything.  From it you make the risk management decisions.  After the baseline, you may decide to clean it all up, which you will do if it is feasible.  However often it is not possible to do a “complete” cleanup.  So you do a risk assessment based on all the feasible risk management (clean up) alternatives, until you identify the alternative that sufficiently protects public health and the environment.

***Q. Would the ‘do nothing’ alternative for the RA/SI also be used if there were no other viable treatment methods or if the contaminant was itself degrading or otherwise diminishing faster than any available treatment method, even if the contaminant posed a health risk? Or am I separating out treatment when I should instead be grouping it with actions related to public outreach and education?
A. First of all, if the baseline risk assessment, base on the PI or the RA/SI indicates there is no or a very low risk, the do nothing is exactly that – no action is necessary.  If the indicates there is some significant risk, but there is not enough money to clean it up, or it is degrading quickly, then we also do nothing, but maybe put a fence around the site.  We then start a monitoring process, and the whole thing is called “natural attenuation with monitoring.”  Which sounds much better than “do nothing.” 

** Q. Module 2 brought up PCBs often. So I was wondering what about PCBs make them hazardous to humans and ecosystems?
A. There are two hundred or so PCB “congeners,” meaning the same basic arrangement of the two benzene rings, but different amounts and arrangements of the chlorine.  The toxicity of the congeners is very different – only some are harmful to humans.  However, most of the PCBs are very persistent in the environment and bioaccumulate up the food chain.  The harm to the environment would be extremely diverse and essentially unknown. 

**Q. In what medium do PCBs pose the greatest risk to humans?
A. The volatility and solubility of PCB congeners again varies quite a bit.  Those with only one chlorine may be slightly volatile, while those with more chlorines become much less volatile and the heavier congeners are solids.

*Q. Are the ‘remedial design’ and ‘remedial action’ phases part of risk assessment or risk management?
A. Yes.

*Q, Are all CERCLA/Superfund sites non-current/abandoned hazardous waste sites?  I worked at Los Alamos National Laboratory for a while last year and I thought it was a Superfund site but it was still very much an active facility.
A. The waste portion of it is non-current.  Many superfund sites are on active military bases and such.  The site is cordoned off, physically and/or administratively, and then life goes on elsewhere.

*Q. I was a bit confused about what is meant by regulatory matrix. Could you elaborate on this
A. That’s just a general term that that indicates many agencies and sets of regulations are often involved, as well as levels of government: federal, state, and sometimes local.

*Q. How is CERCLA funded?  The EPA site mentioned a trust fund established by taxing the chemical and petroleum industries.  Is this an ongoing tax?  Any idea of the size of the tax or how it is levied?
A. There is a tax on chemicals and petroleum, but it is insufficient, so congress chips in from the general fund.  However most CERCLA (“superfund”) sites are cleaned up the “responsible parties”  (AKA “potentially responsible parties” PRP)

*Q. I have heard that agricultural run off is a big contributor to the problems in the Chesapeake Bay.  Has the EPA taken any steps to regulate toxic chemicals released by farmers?
A. It if it is not from a “point source” it is not directly regulated.  There is an ongoing drive to regulate agricultural runoff and I’m not sure of the current status.  However the biggest problem is not “chemicals” but animal waste and nutrients.

*Q I notice that you use different terms than I for environmental documentation…is this a result of occupational preference?  For example….feasibility study, I am assuming is the same as an initial study, due diligence, or environmental site assessment?  
A. I follow the superfund definitions from RAGS if I mean a definite step.  However I sometimes am speaking in generalities and use more general terms.  We will do something with due diligence in a later module.

Q. Any type of activity, even those which sound “good” like gardening, has its own degree of impact on environment. So the risk assessment should be considered. From my working experience I remember a part of work which was called “Environmental Impact Assessment”. My question: should Environmental Impact Assessment be done before any project? I mean does it relate to any activity: construction, extraction, mining, remediation, etc.? Should it be done even if a project is really small?
A. In general, as an ethical person, I should try to not harm other people by my actions.  I recognize that many of my actions will have some effect on the environment, but that the effect will be immeasurably small.  The government, however, makes laws to protect the health and safety of the public.  These laws always have minimums or thresholds, below which the law does not apply. Some of these have scientific reasons for the minimum, while others are political.  My favourite relates to underground fuel tanks.  The threshold is 1100 gallons, smaller than that, they do not have to be tested for leaks.  The reason for that 1100 number is that they typical home tank is 1000 gallons or less.  So the law exempted most homeowners.  If it did not, the law would not have been passed. 

Q. Landfills are not only the areas for wastes storage but also the contaminant sources too. Its location should be based on suitable geologic conditions. If such a place is found in one of the American states, but this state authorities do not want to have it, can a Federal (or National) Authority Body make them obey the order or it should go through some legal procedure like voting? 
A. The federal law distinguishes Municipal Solid Waste (MSW) which is presumed non-hazardous, from Hazardous waste.  The MSW is mentioned in the federal regulations, but not regulated to any great extent.  Hazardous waste is regulated by the federal government.  The rational is that almost all MSW stays within the state where it was generated, while hazardous waste was often transported across state lines.