Gulland points out that blubber samples of sea lions who died of cancer also show high concentrations of the pesticide dichlorodiphenyltrichloroethane ( DDT ) , in part because many are born near the Channel Islands where 1,700 tons of the toxin were dumped prior to its ban in 1972 . + Video : What Happens to Sex Offenders ? + Why Are Women Flocking to Horror Films ? + Could Jogging Be Bad for You ? + Do Diet Restrictions Help With Autism ?