We now know what happens to all the PCBs and DDT that's spewed into our environment – it ends up in ivory gulls. The Arctic birds were recently found to have the highest concentrations of PCBs and DDT when its eggs were tested. The more interesting point is that both of these chemicals are banned in many countries, though DDT is still used to control disease vectors in some countries.
So how did this happen? Well, the prevailing winds sweep these chemicals from around the globe and concentrate them in a swirling mass in the Arctic. From here, the chemicals accumulate in the fatty tissues of birds, fish and other animals. Ivory gulls are top predators, meaning they eat fish and scavenge dead seals and, yes, polar bears. Any chemicals that are in these animals are then passed onto the gulls, so basically the gulls are eating DDT and PCBs for dinner every night. Bon appétit!