PBDEs, PCBs and OC pesticides are all ubiquitous environmental pollutants. Whilst the last two were introduced in the environment far earlier than PBDEs, they were subsequently banned and/or restricted and their concentrations are decreasing in the environment. PBDEs on the other hand have only recently been recognised as environmental pollutants and their levels have been shown to increase over the last two decades. This talk will investigate the concentrations of PBDEs and other organohalogens (PCBs and OC pesticides) in seals and humans from the United Kingdom, with PBDEs as the main focus. First, the occurrence and distribution of PBDEs in the blubber of free-living grey seal (Halichoerus grypus) pups born in the Farne Islands (on the east coast of the UK) and their relationship to concentrations of PCBs and OCs will be investigated. Secondly, the distribution of PBDEs in human breast milk samples from two different UK regions (inner city London and rural Lancaster) will be investigated, establishing data on previously unavailable UK trends, and relating PBDE concentrations to those of PCBs and OCs, speculating on the role that demographic location may play in influencing such levels.