Pond and lake sediments are often reservoirs for anthropogenically released heavy metals, making them ideal for recording regional pollution history and trends. To improve upon the knowledge and mechanisms of anthropogenic heavy metal pollution in rural areas I analyzed a sediment core from a mill pond in James City County, Virginia for lead and zinc. The heavy metals were extracted using nitric acid digestion and evaluated using ICP-OES to identify the atomic composition of the samples. Within the sediment, lead recorded significant periods of environmental history, which was captured in the increase and decrease of its concentration. Such significant periods included peak consumption of leaded-gasoline and the passage of environmental legislation in the 1970’s and 1980’s. The pre-industrial average concentration of lead was 19.4 μg Pb/g and the post-industrial maximum concentration was 39.7 μg Pb/g which was reached in 1960. The peak concentration of lead is attributed to an increase in leaded-gasoline use in the James City County area. Zinc recorded extremely elevated and dangerous concentrations within the sediment. Zinc had a stable background average concentration of 56.2 μg Zn/g prior to increasing rapidly in 1976 to a concentration of 703 μg Zn/g. The peak concentration of zinc coincides with the operation of the James City County Landfill that lies to the north of Jolly’s Mill Pond. I suggest zinc originated via ash from incinerated waste and became deposited in the sediment.
Hart, Chrissy, "Sifting through sediment: Evaluating zinc in the remote Gordon Creek Watershed, Virginia" (2022). Geology Senior Theses. William & Mary. Paper 26.