Aquatic species have these chemicals and debris forced on them against their will. As stated in the article "Combined Sewer Overflows", treatment plants cannot handle the ingress of water and the waste it contains, so they push the water and waste into the ocean ("Combined Sewer Overflows"). Since humans are unable to handle the event, aquatic species become entangled or suffocate in all the garbage and waste from humans. Oil spills are another case where animals are victims of human actions. “Even one part oil per million parts of water can be harmful to the reproduction and growth of fish, shellfish, and plankton” (“Threats to Aquatic Environments”). Even the smallest amount of oil will affect the life of any Oil spills also block sunlight, since oil is lighter than water, oil simply settles on top of the water (“Threats to Aquatic Environments”). When oil sits like this, it blocks sunlight from aquatic plants and kills them. Another problem caused is that when aquatic plants die they sink to the bottom of the water, suffocating other organisms that cannot move quickly or at all. Oil spills have been devastating to many species for years since the 1989 oil spill in The species was so devastated that it is still trying to recover from the spill today (“Threats to Aquatic Environments”)