Five years ago, a killer whale called Lulu washed up on the shores of Scotland. She was thought to be over 20 years old, though autopsies revealed she had never had any offspring. Tissues recovered from Lulu suggested she was one of the most PCB-contaminated animals on the planet. She came from the UK's only resident killer whales, a group of eight, none of which had ever had young and are now considered infertile from pollution.