Distribution of Heavy Metals and Trace Elements in Soils of Southwest Oregon

Khandoker, Rafiqul Alam

doi:10.15760/etd.6575

Cited by 2 publications

(11 citation statements)

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“…Forested land includes any land with greater than 20% tree cover, while Transitional includes that with less than 20% tree cover. The total Hg soil concentration (0.07 mg kg −1 ) is the median of estimates for the "A" and "B" horizon soils (Khandoker, 1997 Table I). Volatilization of Hg(0) from soils is an important Hg flux from terrestrial systems but its measurement is highly uncertain, with reports of rates varying from <1 ng m −2 h −1 to ≈90,000 ng m −2 h −1 (Schlüter, 2000;Grigal, 2002).…”

Section: Land (M 2 )mentioning

confidence: 99%

A mass Budget for Mercury in the Willamette River Basin, Oregon, USA

Hope

2005

Water Air Soil Pollut

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In Oregon's Willamette River Basin (Basin), health advisories currently limit consumption of fish that have accumulated methylmercury. Under the Clean Water Act, these advisories create the requirement for a mercury Total Maximum Daily Load (TMDL), which, in turn, created the need to better characterize the cycling of mercury in the Basin. This paper presents: (a) a mass balance model relating the processes, reservoirs, and fluxes of the Basin's mercury cycle, (b) first-approximation estimates of reservoir masses, flux rates, and turnover times, and (c) an assessment of the impact of anthropogenic mercury sources on this cycle. Deposition from the atmosphere to land is estimated to be the largest (587 kg yr −1 ) single flux; with much (≈54%) of this deposited mercury returned to the atmosphere via volatilization. Combined local anthropogenic (360 kg yr −1 ) and global emissions (390 kg yr −1 ) substantially overshadow all other anthropogenic point-source inputs. Runoff of mercury from native soils (particulate and dissolved phases) was estimated as the largest (≈70%) single source of Hg to surface water; contributions from anthropogenic air emissions deposited on land and then transported as runoff were ≈17%. All other currently identified and quantifiable nonatmospheric anthropogenic point sources made a small (≈5%) contribution to total loadings. These first-approximation estimates suggest that management of soil erosion should have a higher priority than reductions in local anthropogenic air emissions, with the caveat, however, that the degree of linkage between any such reductions and that of methylmercury levels in fish is presently unclear. Additional work will be required to develop the better parameterized and calibrated model needed to predict the outcome of Hg loading reduction alternatives under consideration within the TMDL process.

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Section: Land (M 2 )mentioning

confidence: 99%

A mass Budget for Mercury in the Willamette River Basin, Oregon, USA

Hope

2005

Water Air Soil Pollut

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“…The study area is from the Pacific Ocean on the west to the city of Bend on the east, the Oregon-California border on the south up to the city of Eugene on the north. The bounds of this study area were chosen to be consistent with a study by Khandoker (1997), since soil samples from Khandoker's study were retested for arsenic for use in this study.…”

Section: Study Areamentioning

confidence: 99%

“…The geologic map of Oregon created by the United States Geological Survey (Walker and MacLeod, 1991) was used as a base map for this study to ensure consistency with arsenic studies done in Oregon previous to this study (Khandoker, 1997;Douglas, 1999). The map was obtained online, and ArcGIS software was used to isolate the lithologic polygons in the southwest Oregon study area.…”

Section: Geographic Information Systemsmentioning

confidence: 99%

“…Originally, the Department of Environmental Quality (DEQ) set remediation standards to one part per million (ppm) of arsenic, but Khandoker (1997) found natural values can be higher in Oregon. For northwest Oregon, Ricker (2013) showed many samples from undisturbed soils were higher in arsenic than one ppm.…”

Section: Chapter I: Introductionmentioning

confidence: 99%

“…As shown in Figure 6, arsenate is more stable under oxidized conditions, while arsenite is more stable at moderate to low redox potentials below the limits for arsenate (Inskeep et al, 2002). Khandoker (1997) summary statistics and background statistics were used to calculate a regional default background concentration at the 95-percent upper limit (Table 1).…”

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confidence: 99%

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Naturally Occurring Background Levels of Arsenic in the Soils of Southwestern Oregon

Hurtado¹

2000

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Dr. Scott Burns, your encouragement and confidence has made the process of creating this Master's thesis much more enjoyable than I imagined it could be. Also, I learned a lot from you! David Anderson from DEQ and Neil Morton from GeoEngineers, Inc. were both invaluable resources for questions I had regarding the DEQ data set. I thank Kassandra Lindsey and Aubrey Frimoth for being my post-surgery arms and legs with their physical contributions (digging many holes) and can-do attitude in the field. Classmates Traci Parker and Kimberly Yazzie joined me in playing with my data for a class project, helped troubleshoot appropriate analyses for the data and traded ideas for what the results may imply. To my immediate family: thank you, parents, for emotional support and perspective, always. I also very much appreciate my dog, Daisy, who has kept my toes warm while snuggled under my desk during all of my higher education. My fantastic husband, Josh, with his patience of steel, earns my lifetime of gratitude; he has sacrificed many date-nights through both my Bachelor's and Master's education. Josh, without your sense of humor and support, I would not have had the fun and focus that I am grateful to have experienced through these degrees. Last but not least… Liam, welcome to the world, my son! v

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Distribution of Heavy Metals and Trace Elements in Soils of Southwest Oregon

Cited by 2 publications

References 21 publications

A mass Budget for Mercury in the Willamette River Basin, Oregon, USA

A mass Budget for Mercury in the Willamette River Basin, Oregon, USA

Naturally Occurring Background Levels of Arsenic in the Soils of Southwestern Oregon

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