Metal contamination within the Oklahoma portion of the Grand Lake watershed: Assessment of toxicity risks to aquatic and terrestrial biota and implications to tribal human health
Garvin, EM
| HERO ID | 7572426 |
|---|---|
| Year | 2016 |
| Title | Metal contamination within the Oklahoma portion of the Grand Lake watershed: Assessment of toxicity risks to aquatic and terrestrial biota and implications to tribal human health |
| Authors | Garvin, EM |
| City | Tulsa, OK |
| Abstract | The Grand Lake o’ the Cherokees (Grand Lake) watershed is located in southeastern Kansas, southwestern Missouri, and northeastern Oklahoma. Since the mid-1800s, the watershed has experienced metals contamination as a consequence of historic Pb and Zn mining operations within a 6,500 km 2 area known as the Tri-State Mining District (TSMD). The Tar Creek Superfund Site (TCSS) comprises a 3,077 km2 portion of the TSMD within which there have been extensive studies of metal concentrations in environmental media. In Oklahoma, there have been limited studies assessing metal concentrations within potentially impacted environmental media outside of the TCSS boundary. The findings presented within this dissertation demonstrated the presence of metals contamination in present-day streambed sediments and floodplain soils outside the TCSS boundary. Results indicated that the presence of metals contamination within these environmental media are of sufficient concentrations to pose toxicity risks to benthic invertebrates and plant populations as far downstream as the upper end of Grand Lake. Recent (2009-2011) consumption survey data showed that tribal communities, including children, consume a wide variety of biological resources from metals contaminated portions of the watershed, including many species of plants, fish, benthic invertebrates, birds, and mammals. This study established that metal concentrations within many species of plants warranted consumption restrictions for plants growing on the floodplains of Elm Creek, Grand Lake, Lost Creek, Spring River, and Tar Creek. A stream-specific consumption restriction guide specifying the weekly number of allowable servings of each species was developed for tribal children and adults. The purpose of this guide was to inform and raise awareness of tribal communities, risk assessors, and risk managers concerning tribal health risks. Importantly, this dissertation demonstrated that many species of plants can accumulate sufficient metal concentrations to exceed dietary limits for one serving even when soil metal concentrations are not exceptionally elevated relative to reference conditions. Consequently, exposure risks associated with the consumption of plants should be based on metal concentrations within specific plant organs and species on a site-specific basis. A weekly consumption scenario was created within this dissertation in order to better understand the potential metal dietary exposures to a child and an adult tribal member who consumes multiple servings of multiple plant species per day, as well as benthic invertebrates and fish from the watershed. The findings of the tribal diet scenario showed that plants pose a greater consumption exposure risk for tribal members than benthic invertebrates or fish. Therefore, without the consideration of exposure risks associated with the consumption of plants within future human health risk assessments, tribal health risks will be severely underestimated. Analysis of the sediment profile within an oxbow lake of the Spring River indicated that since the late 19th century, metal concentrations have been at considerably greater levels than those found in present-day sediments. Specifically, metals in sediments have been of sufficient concentrations to pose moderate to high toxicity risks to benthic invertebrates during the majority of the last 138 years. Since the work presented in this dissertation indicated that present-day sediment metals concentrations produce both ecological and human health risks sufficient to cause extensive tribal losses of use of biological resources, the higher sediment metals concentrations present in past times would have resulted in larger ecological and human health risks and a concomitant increase in the loss of use of biological resources to tribal communities. These losses will persist for future generations until risk-based decision making and remedial/restoration efforts within the downstream area in Oklahoma are focused on the protection of tribal health and supportive of cultural practices. |
| Url | https://search.proquest.com/dissertations-theses/metal-contamination-within-oklahoma-portion-grand/docview/1854183211/se-2?accountid=171501 |
| Is Certified Translation | No |
| Dupe Override | No |
| University Name | University of Tulsa |
| Paper Level | Doctoral Dissertation |
| Is Public | Yes |
| Language Text | English |