Heavy metal chronology in lake sediments downwind of a coal fired facility.

摘要

Arsenic, cadmium, copper, mercury, lead, and zinc are emitted by a variety of human activities, including coal combustion at coal fired facilities. These heavy metals have recognized human and environmental health impacts, and their emissions are subject to government regulation. Studies investigating coal facility heavy metal emission show a variety of results. This project characterizes depositional trends of arsenic, cadmium, copper, mercury, lead, and zinc, in lakes downwind from a coal fired facility by reconstructing heavy metal deposition rates over time. Shifts in heavy metal deposition rates are identified using cumulative frequency plots. The shifts are age dated by using the deepest shift in lead deposition rate as an absolute age marker representing the year 1900. The sedimentation rate is determined from the depth where the shift in lead occurs. This sedimentation rate is used to age date the shifts in the other heavy metal influx profiles. The depth profiles of the heavy metals show changes in the rate of deposition which coincide chronologically with local changes in human activity. Understanding the processes and sources that control the heavy metal deposition in the study area has implications for future environmental decision making.