Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves

by James Nestor

Dr. Roger Payne, an ocean conservationist, analyzed sea life for PCBs and found that orcas had about 400 parts per million of PCBs—eight times the toxic limit. He found beluga whales with 3,200 ppm of PCBs, and bottle-nosed dolphins with 6,800 ppm.