Organochlorine Contaminants and Reproductive Implication in Cetaceans: A Case Study of the Common Dolphin

Abstract Organochlorines, such as polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), are persistent organic pollutants that both bioaccumulate and biomagnify within marine food webs. These legacy pollutants are known endocrine disruptors and have been reported to have adverse effects on endocrine, reproductive, and immune functions in humans, laboratory animals, and wildlife. This chapter will review evidence of pollutant-mediated effects on the reproductive system in cetaceans from exposure to PCBs and DDT. In addition, an assessment of reproductive failure and reproductive dysfunction was undertaken on stranded and bycaught female common dolphins from the Northeast Atlantic, and their association with exposure to PCBs was investigated. Within the sample, 16.8% (18 out of 107) of females presented with reproductive system pathologies that were associated with higher blubber ΣPCB lw concentrations, above the threshold for the onset of adverse health effects in marine mammals. Cases of reproductive failure were also reported that may be linked to exposure to these endocrine-disrupting chemicals. The continued exposure to legacy pollutants, and new emerging pollutants, raises concerns about the current and future population-level pollutant effects on Northeast Atlantic common dolphins.