A High-Resolution Mill Pond Record From Eastern Virginia Reveals the Impact of Past Landscape Changes and Regional Pollution History

Spheroidal Carbonaceous Particles in a Virginia Mill Pond Provide a Record of Local and Regional Coal Combustion

“…The high sedimentation rate in Lake Matoaka give this study excellent resolution. As such decadal scale observations of changes in population and industry, locally and regionally, over the past 315 years are observed clearly in the concentration and accumulation curves (Kaste et al, 2016;Balascio et al, 2019). This distinguishes our study from those published in the literature.…”

“…The area experiences high annual precipitation of 1.1 m/yr (Kaste et al, 2016). High annual precipitation in a largely unconsolidated sedimentary bed, allows for high sedimentation rates throughout the year in all local catchments (Balascio et al, 2019).…”

“…7) using a push coring system with a piston rig. The core was dated using 210 Pb, 137 Cs, and 206 Pb/ 207 Pb, developing a very fine scale age model across the 148 cm long core (Balascio et al, 2019). The deepest layer of the core, 148-126 cm, shows cypress root fragments and poorly oxygenated black muds consistent with a swamp environment.…”

“…Previous research shows, at 55 cm, correlated to 1910, the earthen dam was stabilized due to construction of Jamestown Road. This stabilized the lake levels and sedimentation rates, requiring a slightly different sampling interval to achieve higher quality resolution (Balascio et al, 2019). Sample conservation was paramount as this is an archived sediment core, therefore when extracting the sediments, only enough was removed such that dry mass was less than 0.2 g. Samples were dried in an oven at 80℃ for 72 hours.…”

“…SCP normalized to known sedimentation rates over time and compared to total Pb concentration up-core. Sedimentation rate and total Pb data taken from the literature, c/o Balascio et al, (2019). All three plots show year by year concentration increase beginning in 1730, decreasing after 1800, increasing in 1860, with sharp rise and peak 1950.…”