Frequently asked questions
Contamination or pollutants in sediment can come from a variety of sources. Heavy metals (such as copper and zinc) and oils (polycyclic aromatic hydrocarbons) can come from automobiles. Other chemicals (such as PCBs) can come from industrial discharges that took place years ago or from yards and streets where people use chemicals (pesticides and fertilizers). Some pollutants found in sediment can date back to times when there wasn't wastewater treatment or containment of polluted discharges. Others are in the air and dust that get deposited on the ground and washed into our waterways.
In general, the pollutants come from all of us. Each person can contribute to the pollution found in sediments by many common things we do in living our daily lives.