Environmental pollution has been steadily increasing after the industrial revolution and the consequential increased human activity. A contemporary trend of concern is chemical pollution, and one class of chemical pollutants are endocrine disrupting chemicals (EDCs). These compounds have the ability to impair endocrine function in organisms, and can therefore induce molecular or physiological sub-lethal effects. EDCs enter marine environments either with wastewater or off shore industrial activities, such as oil drilling. Marine organisms can be exposed either chronically through presence of low concentrations of EDCs in the environment, or through accidental spills, such as the Deepwater Horizon (DWH) oil spill in the northern Gulf of Mexico (NGOM) in 2010. The blue crab, Callinectes sapidus, is an economically and ecologically important invertebrate in the NGOM. Because the blue crab has both pelagic and benthic life history stages, it is possible that the blue crab can encounter pollutants from both near shore and off shore sources. Also, this biphasic life history makes the blue crab an important link between pelagic and benthic ecosystems. In this dissertation I investigated what contaminants are present in post-larval blue crabs on a wide spatial scale, and if evidence of contamination from the DWH oil spill can be detected. I also exposed juvenile blue crabs to oil, dispersed oil, and two wastewater compounds and measured effects on growth and gene expression. This research provides important information about contemporary contaminants in the NGOM and how environmentally relevant concentrations of contamination affects blue crabs on a sub-lethal level.