To be skinny.
Sewage is waste matter from domestic and industrial establishments, what causes it....Humans
It is because throw trash and materials and dump chemicals, that can really hurt and kill sea life.So unless you want to be a sea killer than don't pollute the ocean!
from sewage
Human beings using the toilet.
Vehicles, litter and sewage.
Through the mouth of rivers that reach the ocean and precipitation (rain and snow).
Industrial waste and sewage
Sewage is a breeding ground for bacteria and viruses. It is not safe at all to inhale the fumes of sewage as a result. Several types of pathogens could enter the sinus and lungs and multiply within the body.
Common causes of blockages in a sewage drain include the buildup of grease, hair, soap scum, food particles, and foreign objects like wipes or sanitary products.
Possible causes of a sewage smell coming from the bathroom sink include a dried-out P-trap, a clog in the drain, or a problem with the sewer venting system.
Oil, Gasoline, Sewage,pesticides, etc.
Yes, I think I see what you are getting at: The only thing that affects the flow of a river is gravity. Put simply water flows downhill. But because water is a fluid the graviational effect of the moon causes tidal flow which has an effect which we see in estuaries, that is rivers where they enter the sea. In aeas of the earth which have a small tidal range rivers do not have estuaries they form deltas....