Endocrine Disruption in Freshwater Fish from Contaminants of Emerging Concern

Emerging pollutants are a class of new chemicals that are not commonly monitored for their environmental presence but have the potential to enter the environment and cause adverse biological and ecological effects. The scientific community has awakened to the challenges posed by such pollutants in our environment, and there is a plethora of scientific literature to suggest that these contaminants are potent even at trace levels. Various environmental monitoring bodies, such as the EPA, REACH-ECHA and NORMAN, have also recognized the threat from these emerging contaminants. Contaminants of emerging concern are mostly the chemicals synthesized for human utility, for example, ingredients in pharmaceutical and personal care products and chemicals used in plant protection systems and fire prevention. Properties, such as increased bioavailability and bioreactivity of pharmaceutics and pesticides and increased persistence of halogenated aromatics, make them highly efficient at eliciting biological reactions even at low concentrations. Nanoparticles have emerged as one of the newest classes of contaminants in the twenty-first century, and they too have the ability to interact with biological pathways and disrupt them. The inventive and inquisitive nature of humans is expected to introduce more novel chemicals into the aquatic environment in future which will keep the scientists busy in investigating their biological effects. This chapter is expected to act as a primer for various budding ecotoxicologists to initiate their interest in the toxicology of contaminants of emerging concern.