DDTs and PCBs build up in the fatty parts of fish. To lower the amount of these chemicals in the fish you eat, remove these fatty parts and follow these recommendations:
Eat only the fillet. Use only the fillet when making soup.
Remove and throw away the head, guts, kidneys, liver and fatty parts such as the skin and belly flap before cooking.
Bake, broil, steam or grill fish, letting fatty juices drip away.