College of William and Mary W&M ScholarWorks Undergraduate Honors Theses Theses, Dissertations, & Master Projects 5-2014 Land Use Impacts on Selenium Accumulation in Vegetation and Soil Sharon E. Hartzell College of William and Mary Follow this and additional works at:https://scholarworks.wm.edu/honorstheses Part of theEnvironmental Indicators and Impact Assessment Commons Recommended Citation Hartzell, Sharon E., "Land Use Impacts on Selenium Accumulation in Vegetation and Soil" (2014).Undergraduate Honors Theses. Paper 96. https://scholarworks.wm.edu/honorstheses/96 This Honors Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Undergraduate Honors Theses by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. Table!of!Contents! ! List!of!Tables……………………………………………………………………………………………………………!!3P4! ! List!of!Figures…………………………………………………………………………………………………………….!5! ! ! Abstract……………………………………………………………………………………………………………………….6! ! ! Introduction……………………………………………………………………………………………………………7P12! ! ! Chapter!1:!Validation of Analytical Methods for the Analysis of Selenium in Vegetation! ! Background…………………………………………………………………………………………………13P14! ! Methods………………………………………………………………………………………………………14P21! ! Results…………………………………………………………………………………………………………21P29! ! Discussion……………………………………………………………………………………………………29P31! ! ! Chapter!2:!Land!Use!Impacts!on!Selenium!and!Mercury!Accumulation!in!Vegetation! ! ! Background………………………………………………………………………………………………………32! ! ! ! Methods………………………………………………………………………………………………………32P38! ! ! Results………………………………………………………………………………………………………..38P53! ! ! Discussion…………………………………………………………………………………………………54!–!64! ! ! Conclusions!and!Future!Directions………………………………………………………………………65! ! Acknowledgments…………………………………………………………………………………………………66! ! Works!Cited…………………………………………………………………………………………………………67P73! ! ! ! ! ! ! ! 2! List!of!Tables! ! Table!1:!CoalPtoPCrust!Ratios!of!Elements……………………………………………………………………!15! ! Table!2:!Program!for!Graphite!Furnace!Atomic!Absorption!Spectrometry…………………….19! ! Table!3:!Digestion!Efficiency……………………………………………………………………………………..…22! ! Table!4:!Optimal!Digestion!Time……………………………………………………………………….…………22! .! Table!5:!Digestion!Efficiencies!–!Trace!Metal!Recoveries………………………………………………23! ! Table!6:!Selenium!Recoveries,!UV!Digestion!vs.!Microwave!Digestion……………………………24! ! Tables!7!&!8:!Repeated!Analysis!of!Se!Concentration!in!CRM!and!WQB3,!Peak!Area…24P25! ! Table!9:!Percent!Recoveries,!Peak!Height…………………………………………………………………….25! ! Table!10:!Limit!of!Detection!for!Peak!Height……………………………………………………………….26! ! Table!11:!Selenium!Concentrations!in!Vegetation………………………………………….……………38! ! Table!12:!OnePWay!ANOVA!of!Six!Sample!Sites……………………………………………………………39! ! Table!13:!Selenium!in!Vegetation!Samples,!3PWay!Categorization!Based!on!Land!Use…..41! ! Table!14:!OnePWay!ANOVA!of!ThreePWay!Land!Use!Categorization!…………………………….42! ! Table!15:!T!Test!for!Library/Peach!Street!vs.!Williamsburg!Place/Williamsburg! Pottery/Matthew!Whaley……………………………………………………………………………………………43! ! Table!16:!TPTest!for!Library/Peach!Street!vs.!Waller!Mill…………………………………………….44! ! Table!17:!TPTest!for!Williamsburg!Pottery/Williamsburg!Place/Matthew!Whaley,!vs.! Waller!Mill………………………………………………………………………………………………………………….45! ! Table!18:!OnePWay!ANOVA!of!Site!Variability!within!Waller!Mill…………………………………45! ! Table!19:!Sites!within!Waller!Mill……………………………………………………………………………….46! ! Table!20:!Selenium!in!Soil,!Peach!Street/Library!Sites…………………………………………………..47! ! Table!21:!Selenium!in!Soil,!Williamsburg!Place!Site…………………………………………………….48! ! Table!22:!Selenium!in!Soil,!Waller!Mill!Park!Site…………………………………………………………..49! ! ! 3! Table!23:!Mercury!Concentration!at!Six!Test!Sites………………………………………………..………51! ! Table!24:!OnePWay!ANOVA!for!Mercury!at!6!Sites………………………………………………….……..51! ! Table!25:!Mercury!Concentrations,!3PWay!Land!Use!Categorization………………………………52! ! Table!26:!OnePWay!ANOVA!of!Mercury!3PWay!Land!Use!Categorization………………………...53! ! Table!27:!Selenium!in!Pine!Needles,!Literature!Comparison………………………………………….54! ! Table!28:!Mercury!in!Pine!Needles,!Literature!Comparison………………………………………….56! ! 4! List!of!Figures! ! ! Figure!1:!Demonstration!of!UV!Digestion!Method……………………………………………………..….17! ! Figure!2:!Normal!Test!Plot!for!Limit!of!Detection!Data…………………………………….……………27! ! Figure!3:!Standard!Curve!Plot!showing!Standard!Deviations………………………………………...28! ! Figure!4:!Map!of!Sample!Sites!in!the!Williamsburg,!VA!Area…………………………………………33! ! Figure!5:!Wiley!Mill!used!to!Grind!Pine!Needle!Samples…………………………………………….…35! ! Figure!6:!Scale!Image!of!Ground!Pine!Needles……………………………………………………………...35! ! Figure!7:!Average!Selenium!Concentrations!at!Test!Sites………………………………………………40! ! Figure!8:!Average!Se!Concentration,!3PWay!Land!Use!Categorization…………………………….43! ! Figure!9:!Selenium!in!Soil,!Peach!Street/Library!Sites………………………………………….………..47! ! Figure!10:!Selenium!in!Soil,!Williamsburg!Place!Site………………………………………….………….48! ! Figure!11:!Selenium!in!Soil,!Waller!Mill!Park!Site………………………………………….………………49! ! Figure!12:!Mercury!Concentration!at!Six!Test!Sites…………………………………………..……………50! ! Figure!13:!Mercury!Concentration,!ThreePWay!Land!Use!Categorization……………………….52! ! Figures!14!and!15:!Library/Peach!Road!Sites………………………………………………………………59! ! Figures!16!and!17:!Williamsburg!Pottery!Site……………………………………………………………..60! ! Figures!18!and!19:!Williamsburg!Place!Site……………………………………………………….………..61! ! Figures!20!and!21:!Matthew!Whaley!Site……………………………………………………………………62! ! Figure!22:!Waller!Mill!Park!Site……………………………………………….………………………………….63! ! ! ! ! ! ! ! ! ! 5! Abstract! The!impacts!of!coal!combustion!on!environmental!and!human!health!are!well! known,!but!a!growing!area!of!interest!lies!in!the!study!of!unburned!coal!in!the! environment.!Coal!is!enriched!in!a!number!of!elements,!including!selenium,!which!has! known!deleterious!impacts!on!human!health.!Coal!dust!escaping!from!train!cars!during!rail! transport!may!accumulate!in!the!ecosystems!adjacent!to!railroad!tracks,!leading!to!elevated! levels!of!selenium!in!vegetation,!soil!and!water.!In!this!study,!coal!dust!accumulation! related!to!the!transport!of!coal!from!western!Virginia!to!the!shipping!ports!in!Hampton! Roads!is!investigated!in!the!Williamsburg,!Virginia!area.!The!atmospheric!deposition!of!coal! dust!to!vegetation!was!assessed!by!measuring!levels!of!selenium,!an!element!highly! enriched!in!coal,!in!vegetation!samples!collected!adjacent!to!the!railroad!tracks!and!at!an! undisturbed!control!site.!A!UV!light!digestion!method!was!developed!for!the!analysis!of! selenium!in!pine!needles,!and!was!shown!to!yield!comparable!percent!recoveries!to! microwave!digestion!(83%!vs.!80%!recovery!of!selenium!from!certified!reference! material),!with!100%!recoveries!obtained!under!ideal!analytical!conditions.!Correlations! between!rail!transport,!land!use!and!selenium!levels!were!investigated.!Average!selenium! concentrations!ranged!from!0.069!± 0.010 ppm to 0.15 ± 0.046 ppm, with elevated levels at! control!sites!within!Waller!Mill!Park.!Though!selenium!elevation!was!not!found!to!be! correlated!with!rail!transport!of!coal!or!with!increased!development,!sound!analytical! methods!were!established!for!the!further!study!of!this!element!in!vegetation,!and!questions! were!raised!for!future!analysis!of!selenium!in!forested!ecosystems.!! ! ! ! ! 6! Introduction:! ! ! From!mining!to!combustion,!coal!is!a!significant!source!of!environmental!pollution! in!the!U.S.!and!worldwide.!Coal!combustion!products!are!known!sources!of!both!heavy! metals!and!harmful!organic!compounds!to!the!environment,!and!present!risks!to!organisms! and!ecological!communities!through!exposure!and!bioaccumulation!(Mayfield!et!al.,!2013).! A!study!of!the!2008!Kingston,!TN!coalPash!disaster,!one!of!the!largest!coal!ash!spills!in! history,!pinpointed!ecological!and!community!health!threats!stemming!from!water! pollution!and!atmospheric!exposure!to!particulates!(Ruhl!et!al.,!2009).!Though!the!impacts! of!coal!ash!have!been!extensively!studied,!unburned!coal!in!the!environment!is!an!area!of! more!scientific!uncertainty.!The!health!impacts!of!dust!exposure!during!mining!are!well! known,!but!the!environmental!and!human!health!impacts!of!unburned!coal!dust!at!other! points!in!the!coal!cycle!is!still!a!matter!of!concern!(Finkelman!et!al.,!2002).!This!study! investigates!the!loss!of!coal!dust!during!rail!transport!of!coal!by!examining!selenium!levels! in!vegetation!sampled!from!near!railroad!lines!used!to!transport!coal.!! Coal!dust!loss!during!rail!transport!has!been!identified!as!a!problem!by!railroad! companies,!as!coal!dust!can!function!as!a!fouling!agent!for!railroad!ballast!(Tutumluer!et!al.,! 2008,!Huang!et!al.,!2009).!A!number!of!estimates!exist!for!the!extent!of!this!dust!loss.!The! Burlington!Northern!Santa!Fe!Corporation!Railroad!Company!has!reported!that!their!own! studies!indicate!a!potential!loss!of!between!500!pounds!to!a!ton!of!coal!from!a!single!loaded! car!throughout!transit!(BNSF,!2012).!The Oregon Physicians for Social Responsibility have cited that the amount of coal lost in transit can be three percent of the load, and that coal trains can lose as much as 500 pounds of coal per 500 miles traveled (Profita, 2012). Recent research has investigated air quality implications of rail traffic by measuring particulate matter emissions ! 7! associated with passing coal cars, and concluded that residents living near rail lines may be at risk of particulate matter levels above the National Ambient Air Quality Standards (Jaffe et al., 2014). Jaffe et al. reported that the passing of coal cars results in a statistically significant increase in particulate matter at 6.8 microgram/m cubed higher near the rail lines than elsewhere. They estimated that a 50% increase in rail traffic would raise levels above the NAAQS. Virginia rail routes extend from the western part of the state and West Virginia to the coastal ports in Hampton Roads (Wilson, 2000). The!Williamsburg,!Virginia!area!is!subject!to! significant!coal!transport!by!rail,!with!a!set!of!railroad!tracks!operated!by!CSX! Transportation!running!through!the!city.!A!study!of!the!economic!impacts!of!coal!on! Virginia!and!Hampton!Roads!lists!Hampton!Roads!as!the!largest!coal!port!in!the!United! States,!with!coal!exports!at!just!under!43!million!metric!tons!of!coal!in!2011!(Old!Dominion! University,!2013).!Given!the!significance!of!Hampton!Roads!as!a!coal!shipping!port,!and! thus!the!CSX!railroad!line!as!a!major!transporter!of!coal!from!the!Appalachian!regions!of! West!Virginia!and!western!Virginia,!the!ecosystems!surrounding!these!tracks!are!an!ideal! location!to!study!the!potential!accumulation!of!coal!dust.!! Coal is enriched in a number of potentially toxic chemicals, including organic compounds and heavy metals. Coals from the Appalachian Basin are pyrite-rich, and contain elements like arsenic, selenium, mercury, lead, and nickel that are potentially toxic (Diehl et al., 2012). Selenium is particularly enriched in coal, and has been identified by Yudovich and Ketris as a “coalphile” element, with a strong affinity for coal matter (2005). Enrichment factors of selenium in coal to surrounding soils and mineral layers can reportedly exceed 65:1 (Ensminger, 1981, cited in Lemly, 2004). ! 8! Selenium, though an essential trace element for human and animal health, is also toxic in large doses. With dietary deficiency occurring at less than 40 µg per day and toxic levels occurring at greater than 400 µg (Fordyce, 2005). Selenium has the narrowest range between beneficial levels and detrimental levels of any priority or non-priority pollutant (Environmental Protection Agency, 2004). Selenium toxicity occurs through the substitution of selenium for sulfur in proteins, which disrupts their structure and function (Mézes and Balogh, 2009). Se was not recognized as a toxic agent until 1856, when it was recognized as the cause of ‘alkali disease’ or selenosis caused through chronic selenium intoxication (Fordyce, 2005). Selenium toxicity can occur through a number of exposure pathways. Though evidence has been found that inhalation of coal smoke can lead to selenium exposures, ingestion is generally a more important route of exposure (Fordyce). The effects of selenium toxicity occur throughout the food chain from plants to humans. Selenium toxicity has been implicated in waterfowl death, nervous system disorders, and nail and hair loss in humans, livestock, and sea animals (Qui et al, 2011). In addition to toxicity to animal organisms, some plant species experience toxic effects from selenium accumulation, while others are highly tolerant of selenium (Mézes and Balogh, 2009). According to Fordyce, inorganic and organic selenium enter the food chain almost entirely via plants and algae, and are then further concentrated as they pass through the food chain (2005). In the 1960s, an outbreak of human selenosis occurred in the Shanxi and Hubei Provinces of China, and was traced to the consumption of crops grown in soils that included weathering products of high-selenium coal containing more than 300 mg/kg of selenium (Fordyce, 2005). In this outbreak, the main symptoms were loss of hair and nails, as well as nervous system problems and paralysis (Fordyce, 2005). According to the U.S. Environmental Protection Agency, selenium primarily moves through aquatic ecosystems by means of ! 9!