Arsenic speciation and groundwater chemistry at Shepley Hill Landfill, Devens, Massachusetts

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Authors:Hildum, Brendan; Hon, Rudolph; Ahmed, Shakib; Simeone, Robert
Author Affiliations:Primary:
Boston College, Department of Earth and Environmental Sciences, Chestnut Hill, MA, United States
Other:
Department of the Army Base Realignment and Closure, United States
Volume Title:Geological Society of America, Northeastern Section, 47th annual meeting
Source:Abstracts with Programs - Geological Society of America, 44(2), p.46; Geological Society of America, Northeastern Section, 47th annual meeting, Hartford, CT, March 18-20, 2012. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592
Publication Date:2012
Note:In English
Summary:A contaminant groundwater plume beneath a capped landfill in Devens, north-central Massachusetts contains dissolved arsenic concentrations exceeding 15,000 ppb in some locations. The landfill includes solid waste materials deposited over the course of over 100 years and closed in the early 1990's. Beneath the waste material is a several meter thick layer of peat believed to be a part of the historic marshland, a 30 to 100 ft thick sequence of glacial lake deposits, and 5 to 10 ft layer of till overlying the bedrock. The primary source of arsenic has not yet been conclusively determined and likely involves a combination of the landfill waste material, the peat, and/or the underlying overburden sequence. Arsenic mobilization is likely assisted by reducing conditions on decomposition of organic materials within the landfill section. Another possibility is an arsenic bearing groundwater discharging from the underlying bedrock from the oxidation of naturally occurring sulfides. We are presently testing the possibility that arsenic speciation could aid in the better identification of the arsenic source(s) and its transport within the underlying aquifer. Typical arsenic species in natural waters include inorganic arsenite [As(III), As(OH)3], arsenate [As(V), AsO(OH)3], and methylated arsenic, monomethylarsonic acid [MMA(V), CH3AsO(OH)2], an dimethylarsinic acid [DMA(V), (CH3)2AsO(OH)]. Arsenic speciation data along with groundwater parameters such as pH, redox conditions, and other dissolved components may provide further insights about the arsenic sources, the process of its mobilization, and how it is transported through the aquifer.
Subjects:Arsenic; Chemical composition; Chemical fractionation; Geochemistry; Ground water; Hydrochemistry; Landfills; Metals; Peat; Pollution; Sediments; Waste disposal; Water pollution; Massachusetts; Middlesex County Massachusetts; United States; Devens Massachusetts; Shepley Hill Landfill
Coordinates:N420800 N424400 W0710200 W0715300
Record ID:2012085825
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
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