This is especially a problem around industrial centres and big coastal cities. A growing number of rivers are being dammed and dolphins that live within these systems are becoming endangered. More information on habitat loss Information about what you can do go to whale and dolphin links Chemical and nutrient pollution Whales, dolphins and porpoises are vulnerable to the long-term effects of chemical pollution. Some of these pollutants are toxic and can cause death. Others chemicals cause diseases, destroy their environment or reduce their food supply.
Many pollutants accumulate in their body tissue while they feed.
These toxins can remain in their body fats over their whole life. The species most at risk are those that feed high on the food-chain, eating longer lived predatory fish. These are the same group animals found most commonly along our coastlines. In the first weeks of feeding large quantities of these pollutants are passed to calves through their mother's milk. In some populations of dolphins it has become common for the first born calf to die very young from this toxic load.