Water pollution has many forms, all of which are damaging and none of which are less important than the other. Whether it be oil pollution, which is a largely silent (excluding the occasional large spill) but deadly polluter or the widely encompassing chemical pollution which can include Persistant Organic Pollutants (including PCB's and DDT), all water pollution have unimaginable consequences. Some of these effects, which can also be considered further pollutants, are Acid Mine Drainage and Eutrophication. These effects effectively choke out the water they pollute and have the ability to devastate entire ecosystems centered on a water supply.