factors that contribute to contamination

[alpacinoutd]

Hello.

Can I say some "factors" contribute to "contamination" of rivers?

Is this sentence correct and natural?

There are a number of factors that contribute to the contamination of rivers. Firstly, the effluent that is dumped into the rivers is a major problem that needs to be addressed.

[emsr2d2]

The sentence would be OK if you didn't go on to mention something that's actually a contaminant, not a factor.

There are many contaminants in [our] rivers. First, the effluent ...

The effluent isn't a factor. The lack of treatment of that effluent, or the actions of a company that dumps effluent into rivers, are factors.

[alpacinoutd]

The sentence would be OK if you didn't go on to mention something that's actually a contaminant, not a factor.

There are many contaminants in [our] rivers. First, the effluent ...

The effluent isn't a factor. The lack of treatment of that effluent, or the actions of a company that dumps effluent into rivers, are factors.

What about now?

There are a number of pollutants that contribute to the contamination of rivers. Firstly, the effluent that is dumped into the rivers is a major problem that needs to be addressed.

[emsr2d2]

What examples of pollutants that don't contribute to the contamination of rivers are you going to give?

[alpacinoutd]

What examples of pollutants that don't contribute to the contamination of rivers are you going to give?

Do I have to give examples of those things that are not harmful?

[emsr2d2]

No, what I was getting at is that anything that's a pollutant entering a river is, by definition, contaminating the river. It's a bit tautologous.

[tedmc]

We don't normally say comtamination, but pollution of the rivers. Contamination happens with small quantities of materials, e.g. food, fuel, etc.
Effluent is discharged from a source, e.g. factories, not dumped from them. Dumping is the transporting of effluent from a source far away from the dump site.