Endocrine Disruption in the Aquatic Environment

Abstract

Although the words ‘endocrine disruption’ were introduced only relatively recently, some of what are now considered the clearest and best documented examples of endocrine disruption in aquatic organisms were first described 20 or more years ago. These include imposex in molluscs induced by tributyl tin (TBT) and masculinisation of some species of fish living downstream of where pulp mill effluent is discharged. There are now reasonably well-documented examples of what is probably endocrine disruption in a wide range of aquatic organisms from some invertebrates through to reptiles. However, despite this, much still has to be learnt about what chemicals cause these disturbances to the endocrine systems of exposed aquatic organisms, how they do so, and what the consequences of the effects are. The last issue is of particular importance: only in the case of TBT-induced imposex in molluscs has it been shown that exposure to an endocrine disrupting chemical (or mixture of chemicals) can lead to population declines. More research into the consequences of endocrine disruption to wildlife is required before the gravity of this type of toxicity can be determined. Only then can endocrine disruption be assessed in comparison to other factors, such as habitat loss and over-exploitation, which also undoubtedly adversely affect wildlife populations.