Groundwater Modeling and GIS to Determine Exposure to TCE at Tucson

Rodenbeck, Sven E.; Maslia, Morris L.

doi:10.1061/(asce)1090-025x(1998)2:2(53)

“…When direct, past knowledge of contaminant concentrations in drinking water is limited or data are unavailable, historical reconstruction methods can be used to provide estimates of contaminant concentrations. Characteristically, historical reconstruction includes information gathering and data mining activities and the application of simulation tools, such as models, to re-create or represent past conditions [ 1 , 4 , 5 , 15 – 21 ]. For ATSDR’s drinking-water exposure analyses at USMCB Camp Lejeune, methods included linking materials mass balance (mixing) and water-distribution system models to groundwater-flow and contaminant fate and transport models [ 1 , 4 , 5 ].…”

Section: Methodsmentioning

confidence: 99%

Reconstructing Historical VOC Concentrations in Drinking Water for Epidemiological Studies at a U.S. Military Base: Summary of Results

Maslia

¹

,

Aral

²

,

Ruckart

³

et al. 2016

Water

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A U.S. government health agency conducted epidemiological studies to evaluate whether exposures to drinking water contaminated with volatile organic compounds (VOC) at U.S. Marine Corps Base Camp Lejeune, North Carolina, were associated with increased health risks to children and adults. These health studies required knowledge of contaminant concentrations in drinking water—at monthly intervals—delivered to family housing, barracks, and other facilities within the study area. Because concentration data were limited or unavailable during much of the period of contamination (1950s–1985), the historical reconstruction process was used to quantify estimates of monthly mean contaminant-specific concentrations. This paper integrates many efforts, reports, and papers into a synthesis of the overall approach to, and results from, a drinking-water historical reconstruction study. Results show that at the Tarawa Terrace water treatment plant (WTP) reconstructed (simulated) tetrachloroethylene (PCE) concentrations reached a maximum monthly average value of 183 micrograms per liter (μg/L) compared to a one-time maximum measured value of 215 μg/L and exceeded the U.S. Environmental Protection Agency’s current maximum contaminant level (MCL) of 5 μg/L during the period November 1957–February 1987. At the Hadnot Point WTP, reconstructed trichloroethylene (TCE) concentrations reached a maximum monthly average value of 783 μg/L compared to a one-time maximum measured value of 1400 μg/L during the period August 1953–December 1984. The Hadnot Point WTP also provided contaminated drinking water to the Holcomb Boulevard housing area continuously prior to June 1972, when the Holcomb Boulevard WTP came on line (maximum reconstructed TCE concentration of 32 μg/L) and intermittently during the period June 1972–February 1985 (maximum reconstructed TCE concentration of 66 μg/L). Applying the historical reconstruction process to quantify contaminant-specific monthly drinking-water concentrations is advantageous for epidemiological studies when compared to using the classical exposed versus unexposed approach.

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“…Characteristically, historical reconstruction includes information gathering and data mining activities and the application of simulation tools, such as models, to re-create or represent past conditions [1,4,5,[15][16][17][18][19][20][21]. For ATSDR's drinking-water exposure analyses at USMCB Camp Lejeune, methods included linking materials mass balance (mixing) and water-distribution system models to groundwater-flow and contaminant fate and transport models [1,4,5].…”

Section: Historical Reconstruction Methodsmentioning

confidence: 99%

Reconstructing Historical Voc Concentrations in Drinking Water for Epidemiological Studies at a U.S. Military Base: Summary of Results

Maslia¹,

Aral²,

Ruckart³

et al. 2016

Preprint

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0

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A U.S. government health agency conducted epidemiological studies to evaluate whether exposures to drinking water contaminated with volatile organic compounds (VOC) at U.S. Marine Corps Base Camp Lejeune, North Carolina, were associated with increased health risks to children and adults. These health studies required knowledge of contaminant concentrations in drinking water-at monthly intervals-delivered to family housing, barracks, and other facilities within the study area. Because concentration data were limited or unavailable during much of the period of contamination (1950s-1985), the historical reconstruction process was used to quantify estimates of monthly mean contaminant-specific concentrations. This paper integrates many efforts, reports, and papers into a synthesis of the overall approach to, and results from, a drinking-water historical reconstruction study. Results show that at the Tarawa Terrace water treatment plant (WTP) reconstructed ( Author Contributions: All authors contributed to the research discussed in this article. Morris L. Maslia oversaw and directed the water-modeling analyses and Mustafa M. Aral contributed to the development of the water-supply well operation reconstructions, numerical modeling, and probabilistic analysis. Perri Z. Ruckart and Frank J. Bove developed the epidemiological studies protocols for application of water-modeling analyses and conducted the epidemiological studies.

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“…Characteristically, historical reconstruction includes the application of simulation tools, such as models, to re‐create or represent past conditions. A plethora of examples that describe successful historical reconstruction analyses exist in the published literature (Rodenbeck and Maslia 1998; McLaren/Hart‐ChemRisk 2000; Costas et al 2002; Reif et al 2003; Kopecky et al 2004; Maslia et al 2005; Sahmel et al 2010). Application of historical reconstruction methods and approaches to the case‐control health study at Camp Lejeune recognized and required the collective expertise of team members with diverse skills and knowledge and did not focus on one discipline, such as groundwater modeling, as implied in the TPC article.…”

Section: “Hindcasting” Vs Historical Reconstructionmentioning

confidence: 99%