Artificially created substances, Polybrominated Diphenyl Ethers (PBDE) have been widely used by manufacturers since the mid-20th century. Incorporating PBDEs into the products, such as furniture or electric appliances, substantially reduces the intensity of fire as they act as artificial flame retardants. Although, once released into the environment, PBDEs exhibit strong resistance towards environmental degradation and by certain pathways they may collect in various tissues of the human body. PBDEs contamination has been detected across the globe. It is presumed that at some level, PBDEs can be in almost everyone. At high levels, PBDEs may cause severe health problems; therefore, it is crucial to understand how PBDEs are dispersed in the environment. This book is a compilation of several projects implemented at Rutgers University by Archil Zarnadze, Ph.D. and deals with fate and transport of PBDEs in NY/NJ harbor and Lower Delaware River valley. In General PBDEs correlate with temperature but not the population density. Gas-particle partitioning is an important aspect of PBDEs removal from the system. Annual PBDEs loads are 8.7 kg/yr in Delaware Bay and 2 kg/yr in NY/NJ Harbor.