One way to determine risk is already given in here, but it is still a bit picture of overall process of risk management. From figure above, the interesting thing I would point out is how far away the journey of how environmental risk management should undergoes and work.
Initial step that must be considered is pre-research. This kind of research, scientific research, is to obtain contaminant information which is considered to be hazardous. One of the steps is by conducting epidemiology test or observation.
The research of this chemical or a substance, is to find out the dose in which the dose can cause lethal effect to the organisms. If we use 50% population death as an indicator, then we usually use EC50 or LD50. LD50 is a dose of a certain chemical that cause 50% of animal test are dead (lethal dose), another one EC50, is a dose in which 50% of observed animal are experiencing either physiological or structural organ changes. I am not still quite well understood regarding the basic differences between EC50 and LD50, including another study such as clinical study, SAR and modelling. I am personally not well aware of person or community who are their expertise in this area.
Second step is risk assessment. These are when scientists do their job, because the data have to as objective as possible based on real experiment.
At this stage, few things need to done are hazard identification, dose-response curve and exposure assessment. Dose-response activities are similar to how to determine EC50 and LD50, there are also another additional terms such as LOAEC (Lowest Observable Adverse Effect Concentration), or NOEC (No Observable Effect Concentration), etc.
Exposure is a possibility that the target contaminant is present in a certain area or region, dan with certain population either. We can determine the mass of the chemical in the environmental in term of kg/ca perday. The most importance is, how it is likely, us, public community, get exposed or contacted with this chemical. Usually this quite difficult to do, but it's doable. The problem is, again, how big our spirit and government support (political will) to do these activities.
As soon as we get quantitative data, the result should be whether that particular contaminant present any dangerous to the environment or not, then we enter to the third step. On this stage, outside factor may play a bigger role such as politics, economy and especially social. Why, it's because the final output of these researches, these risk assessment would be a regulation, a rule. And this rule must be implemented toward all elements in the society for social safety.
The problem is, it is not easy to issue new decision, new rule. Politic and power may play inside the process. Well, as both you and I can see, politics may change the right thing become wrong and the wrong thing become right. From the objective value, clear picture, that this chemical is hazardous, for example, thus it is obvious need to forbidden its use, but since it will affect, say worker discharge, or another social-control reasosn, this could make the implementation of environmental risk management meet a huge barrier.
But, oh well, the more important thing is at least you already know risk management elements and what involved in it, and the importance to have public authority whom know environmental risk in our surroundings. We are all aware, that only small part of government attention are directed to our environment. This can be seen from our environmental nation budget. Even if, there are some fund directed for environment, this coud only emphasize to end-of-pipe treatment, not to act as a prevention of environmental deterioration.
I still have a hope to my country.. http://www.envirodiary.com/risk-assessment/risk-management.htm