Chemicals from auto emissions, industrial processes, and urban development are found in most urban areas. Two of the chemicals found most abundantly in urban areas are calcium and lead. The calcium comes from all the concrete and the lead comes from oil-based fuels. These chemicals bind to the soil and can be carried by waterways. Often after flooding events, these chemicals are deposited in riparian areas along the waterways. Scientists in this study wanted to find out the chemical content in t Topics: Pollution, Water, Baltimore, Calcium, Lead, Long Term Ecological Research Network, Riparian Areas, Sedimentation.