Characterization of Lake Wapalanne (New Jersey) Sediment Chronology with Environmental Changes
Kiara Jones (Saint Augustine's College) & Elena Noonan (William Paterson University)
Faculty Mentors: Greg Pope, Josh Galster & Huan Feng (Montclair State University)
Lake Wapalanne (Fig. 1), a small lake in northwest New Jersey, was constructed in 1933, which allows for the study of sediment records post and prior to the lake’s formation. In this study, sediment characteristics were compared to environmental changes. Major characteristics that were looked at analyzed were color, carbon content, and particle size. A sediment core was collected out of Lake Wapalanne by inserting a PVC pipe into the sediment, and sectioned every 2 cm (Fig. 2). These samples went through a muffle furnace at 450°C for 8 hours for loss on ignition measurement to determine organic matter content, and the Malvern Mastersizer 2000 for particle size distribution analysis. The color was assessed using the Munsell Soil-Color Charts. The top sediment of the corer was a dark black color, and then became lighter turning into a gley color at the bottom, reflecting a geochemical reaction of organic matter early diagenesis, as indicated by the percent of sediment carbon content decreased with depth (Fig. 3). Finer particles were found at the upper layer of the sediment, while coarser particles were in the deeper sediment depths (Fig. 4). The very bottom of the core decreased in particle size, showing fine particles again. According to the results, the sediment core included lake, stream, and wetland sediment, as suggested by the relationships between color, carbon content, and grain size distributions.
Naturally occurring radionuclides (e.g., Be-7and Pb-210) and anthropogenic radionuclides (e.g., Cs-137) are useful tracers for sediment chronology and mixing study. According to their different half-lives (Be-7: t½=53.3 d; Pb-210: t½=22.3 y; and Cs-137: t½=30.2 y), these radionuclides can be used as tracers for studying the decadal sediment accumulation rates and seasonal sediment mixing (Fig. 5). Future plans include analyzing the sediment for naturally occurring radionuclides (e.g., Be-7and Pb-210) and anthropogenic radionuclides (e.g., Cs-137) using Canberra Model BE2020 Broad Energy Germanium Detector equipped with Model 747 Canberra Lead Shield (Fig. 6) is housed in our Geochemistry Laboratory at Montclair State University. Coupling with the sediment quality assessment, these radionuclides can be used to understand the contamination history since the industrial revolution began. This information is important for Lake Wapalanne environmental protection and assessment.