Microplastics in the oceans can bind with other harmful chemicals, such as PCBs, before being ingested. Alternatively, additives already found in plastic, such as phthalates and Bisphenol A (BPA), leach out of plastic particles and disrupt hormone systems of vertebrates and invertebrates alike. The chemicals in these plastics harm the endocrine, reproductive, and immune systems of living creatures. For example, it is believed that the dwindling orca population is in part due to the ingestion of plastics and these chemicals which have entered the food chain. The orcas cannot produce as they once did and now suffer with low birth rates and miscarriages. This microplastic pollution has far reaching harmful effects on humans, animals and invertebrates alike.