Reports
Sediment Quality Assessment of Blairs Valley Lake, Washington County, Maryland and Franklin County, Pennsylvania
2022, Sylvia, E.R., Gillmor, A., Connallon, C., Van Ryswick, S., and Nicholson, B.
File Reports, Coastal and Estuarine Geology, File Report 20-04
Executive Summary
Maryland Geological Survey, in conjunction with other Maryland Department of Natural Resources programs, including Tidewater Ecosystem Assessment (TEA) and Fishing and Boating Services, was asked to perform sediment quality assessments of state-owned lakes in Maryland. The goal is to provide surficial sediment data for each lake to determine general sediment physical and chemical characteristics as a pre-assessment for potential future lake sediment dredging. Physical and chemical analysis of the sediments from each lake will pose as a baseline for the lake’s sediment data. The sediment data will be incorporated into other study aspects, including fish populations, water quality, and submerged aquatic vegetation (SAV) abundance and distribution in order to generate overall lake health and status.
This report focuses on Blairs Valley Lake in Washington County, Maryland and Franklin County, Pennsylvania. The lake is 22 acres and is located within Indian Springs Wildlife Management Area (WMA). Ten surficial sediment samples were collected throughout the lake and coordinates were stored using Real-Time Kinematic Global Positioning System (RTK GPS). Sediment at each site was described and sampled for analysis. The analysis includes physical properties, including bulk density and grain size, and elemental analysis.
The elemental concentrations of 10 surficial sediments followed similar spatial patterns when plotted by station. The concentrations of major elements Al, Fe, K and Mg as well as the concentrations of trace metals Cu, Ni, Pb and Zn were quite similar to each other in profile-plot, and generally similar to clay content. The concentrations of trace metals As and Cr differed slightly from these others, perhaps because they are less affected by sorption in these environmental conditions. Compared to the relative eco-toxicological screening levels LEL, most trace metals were above the conservative LEL, but only Fe was above the higher SEL in three samples. No eco-toxicological harm is anticipated. Compared to the relative crustal abundance via the use of Fe-normalized enrichment factors, the elements As, Cs, Hf, Pb and Sb are enriched. However, these elements are often encountered in high concentrations in clay-rich sedimentary rocks and the sediments derived from them. No anomalies or outliers were identified.
The 10 collected samples throughout Blairs Valley Lake were similar to sediments of other lakes nearby, including New Germany Lake and Deep Creek Lake. No abnormalities were found in regard to the physical or chemical properties of the bottom sediments of Blairs Valley Lake.
