Very good question! I discuss this at length in a book I am writing. (Not finished yet.)

To me, the working definition of pollution is when the release of a substance or form of energy through human activity exceeds the capacity of the ecosystem (natural or artificial) to dilute or eliminate it, leading it to accumulate to a density (concentration) sufficient to cause an unwanted effect. For pollution to occur, therefore, there has to be human agency in the release, a rate of release exceeding the capacity to get rid of it, and an adverse effect, on the ecosystem or people. The effect has to be adverse because medication, being produced in large quantities and then distributed to individuals for a beneficial effect, could qualify as pollution.

Contamination, however, is simply the presence of some substance or form of energy where it does not belong naturally or by design. Contamination can come from natural sources, it can exist at levels of release the ecosystem can handle, and it does not have to have an adverse or any effect.

Pollution, by this definition, is a subset of contamination. This distinction then becomes very useful in talking about ecotoxicology and contamination.

I will follow discussion on this point with great interest because this definition is important in the logic of the book.

Almost forgot. I count biological agents, such as bacteria, in the definition, not just chemicals and forms of energy.

Tee Guidotti, do you count bacteria in with BOTH pollution and contamination? Man spreading sewage where it didn't occur would then be pollution, - and contamination would be something like an infection with (an overload of) biological agents?

Not exactly. All pollution can be considered contamination, but there can be contamination without pollution. Sewage causes pollution because it has an effect on disease risk. Depends on count and potential effect but disease risk from significant sewage contamination is high and so it therefore counts as pollution. When there are nonpathogenic bacteria in water, that are not naturally occurring, I sound consider than contamination but not necessarily pollution. Even tap water is not sterile, and certainly not pond water.

Life forms may replicate, of course, and that adds a whole different dynamic.

yes, of course, bacteria/biological agents are potentially everywhere - even pathogenic ones. That's why I wanted clarification on your statement that bacteria come into the definition of ..? But the contamination AND pollution with biological agents would be a question of numbers, I guess - more agents (of certain types) than should occur.

I don't see a clear boundary between un-contaminated and contaminated, and between contaminated and polluted, I am afraid. It very much depends on the definition of the "natural" conditions, and when exactly "the release of a substance or form of energy through human activity exceeds the capacity of the ecosystem (natural or artificial) to dilute or eliminate it" is reached. We don't know anywhere near enough about ecosystems' indigenous conditions, nor capacities!, yet. So how to use these two notions appropriately with real data?

Some people reserve the term pollution to Air .. and contamination to water.. do you agree saying water contamination and air pollution?

No, although I used to say the same thing. We do talk about air contaminants and water pollution. I think that the definitions are more useful when contamination is the presence of what doesn't belong and of pollution as contamination from human activity carrying a risk contamination is something you may measure but are not necessarily concerned about except as an indicator that something upstream is wrong, until it reaches a level (such as a count or concentration) that is potentially a risk, in which case it becomes pollution.

Sameh, you started this thread

. What do you think?

Dear Dr Tee, I do appropriate your precise definition of both terms and I do agree with your point of view. Yes, contamination could mean low pollution and pollution may mean highly contamination. If we add the interaction of the human activities, one can say pollution is due to human activity that made the undesirable substance appears above the permissible level in the environment (whatever it is water, air, soil).

Pollution term is used in Broadway- example water pollution, air pollution or noise pollution.When we confined this: example water is polluted by fluoride /arsenic/nitrate etc. Than use the term water is contaminated by fluoride etc. Air is polluted by excessive particulate materials etc.

The definition that I give to my students are the following:

A pollutant is a substance (or energy, or bacteria...) which is present in higher concentration than its natural one due to human influence and which has a detrimental effect on this environment. A contaminant is a substance (or energy...) present in higher concentration than the natural one but without detrimental effect on the environment. And I usually add that our world is definitely contaminated, but not completely polluted.

I would rather say that pollution should be reffered to when a natural water body received (whatever the source) a foreign substance, compound, particles of biological species in quantities that can geopardise the survival of the ecosystem.

Contamination should be related to toxicity. A water may be contaminated for a given species but not for others depending on the ability of the species to wistand the high concentration of the contaminant. We could therefore talk of contamination of drinking water for Human. A water contaminated for Human as drinking water may be good for animals!

Contamination could therefore be related to the health of a given species, while pollution could be related to the whole ecosystem's health.

Theophile , Thanks.

Pollution is a general term that defines the presence of several or a mixture of agents in an environment (water, soil, air) but when we are talking about a specific agent (heavy metal, bacteria, pesticide etc) the term is contamination.

contamination and pollution are synonymous in Spanish, regardless of the amount of the agent to be introduced into the environment.

Language is limiting. The word for safety and for security is also the same in many languages, which makes it difficult in the same conversation to discuss injury prevention as opposed to protection from crime.

We have a contradiction here! Some say "contamination" means an adverse effect and pollution is the general term, and the other half says "pollution" implies an adverse effect and contamination is the general term.

Which is correct?

I would like to know if the discussion about the use of the term contamination and / or pollution is only in academic circles or in the population also. Thank you

Contamination is the presence of a constituent in unusual amounts or concentrations.

Pollution is the presence of a constituent in unusual amounts or concentrations such that an adverse affect on health occurs (ecosystem, human, plant, animal).

The terms are widely misused.

Dear Rolando. The discussion between contamination or pollution is absolutely not a societal question. Most of the people used the term "pollution", but they could not give you a precise definition. The trouble is that (at least in France), this term is used for very different kind of things like smells or plastics that you can see (people talk about pollution sometimes for dirty area).

When I have to discuss about that, I used to say that the entire planet is contaminated, but pollution is not everywhere. This is in agreement with the definition given by John MacArthur. The other point is that it is probably impossible to limit the contamination, but not the pollution.

all types of water pollution is due to contamination, but all contamination in water may not be pollution. Most of the pollutants are harmful to the living species , however all contaminants may not be harmful.

Water pollution is a concern for every person on the earth. Water pollution is contamination of water by water pollutants that are allowed to enter water sources without first being treated to remove compounds that are dangerous to people and animals. Water pollution does not just hurt animals and people alike, they also hurt entire communities doing major damage that takes years to cleanup and fix.

There are many causes of water pollution. One cause is from animal waste that finds its way into the water through a stream or pond. Many times a levy will break and the water will run into the animal yard causing contamination. Sometimes compounds are found in the air and are mixed with water from a rain storm. An oil spill is another example of a water pollution cause.

There are two types of water pollution. The first is point source pollution; this is where contaminants enter the water from a single source that can be located. The second of water pollution is from non-pointed sources, these are sources that do not come from one source but rather many sources working together. An example of this is from fertilized land. Water runoff collects come of the fertilizer from several different fields and the fertilizer finds its way into the water supply causing polluted water. Water pollution is a constant battle all around the world.