Persistent organic pollutants (POPs) are a large and diverse class of chemical contaminants that can cause significant damage to both the natural environment and human health, when present in even small concentrations. POPs include a range of toxic chemical compounds such as dioxins, PCBs, PCDFs, endrin, PAHs and DDT, and are produced as waste materials or by-products during various industrial and commercial processes. Due to their distinct chemical structure and the nature of their interaction with other compounds, POPs can remain present in the environment for large amounts of time, and can pass through food chains and between species.