Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and micro beads) in the Earth's environment that adversely affects wildlife, wildlife habitat, and humans. Living organisms, particularly marine animals, can be harmed either by mechanical effects, such as entanglement in plastic objects, problems related to ingestion of plastic waste, or through exposure to chemicals within plastics that interfere with their physiology. Effects on humans include disruption of various hormonal mechanisms.