Brief Summary of Minutes of Annual Meeting

The annual meeting of the Multistate Research Project, NC1187 convened Tuesday, Oct 23, 2012 at 12 PM in Cincinnati, Ohio in conjunction with the ASA-CSA-SSSA Annual International Meeting. We welcomed Paul Schwab, a new participant from Texas A&M, following Richard Loepperts retirement. Jim Harsh, the current chair reminded the group that his term is completed and Daniel Gimenez will become the new chair, Dan Strawn, vice-chair, and Ganga Hettiarachchi was elected secretary. Their terms will begin in 2013. The meeting began with a report from Nancy Cavallaro on RFPs from NIFA that would be relevant to our project. Relevant topics for NC1187 included nanoparticles in the environment; chemicals of environmental concern, including human and animal waste as well as stormwater. One year of funding was missed so there is significant funding in soil chemistry/contaminant areas. Proposals for graduate and post-doctoral fellows should be considered and take care that the project is not simply a re-statement of an advisors grant. These are meant to generate independent projects for the fellow. Other areas to be funded next year involve climate variability and change, bioenergy, and food safety, including pathogen transport and water quality. Dr. Cavallaro stressed how important it is not to give a Hatch Project the title as a NIFA grant because it can be mistakenly perceived as duplicate funding issues, even though they are normally not. Each participant highlighted some of his or her current work relevant to NC1187. Harsh described the colloid transport studies from his collaboration with Dr. Markus Flury. This work is particularly focused on transport as a function of water content and transient flow. Stephen Anderson is using x-ray computed tomography to follow iodide and iodophenol transport in porous media. Retardation parameters could be estimated from the spatial distribution and compared favorably with those determined by conventional column flow experiments. SSSA will publish the 2nd edition of a Special Publication on tomography in 2012 and Anderson is co-editor. Dr. Rajib attended as a guest and talked about his scanning electron microscope work involving carbon sequestration. Alvin Smucker is using CT to study tortuosity in soil at near micrometer resolution. Tomographic data is interfaced with transport modeling with HYDRUS 3D. Issues of concern are carbon sequestration from bacteria, bacteria transport through pores, effects of long term management on pore structure, and how the use of PEG to increase soil water holding capacity effects root growth. Dr. Ganga Hettiarachchi highlighted two projects. An NSF EPSCOR project on C sequestration is being carried out at long term management sites. She is using EXAFS and spectromicroscopy to get C speciation and distribution as a function of management (e.g. till vs. no-till, manure application). Her second project concerns colloid-contaminant transport and remediation in mining areas from both chemical and microbiological perspectives. She is using XAS for S as well as heavy elements and pointed out that APS is working on a new beamline in sector 13 for S chemistry as well as trace levels of heavy metals. Dr. Don Sparks is looking at C-Fe complexation under different land use regimes. He is also characterizing airborne particulates from poultry waste. He is using synchrotron sources at Brookhaven as well as the relatively less-used Canadian source. He is finding As, Fe, Mn in particles as well as evidence for methylation. Bacteria can be observed in the particles with confocal microscopy.' At the conclusion, Harsh stated that he would compile the last years report and reminded everyone to look at the NCRA Impact Statement Form and to consider what they can add.

Short-term Outcomes: A new, passive particle deposition air sampler, called the EinsteinLioy Deposition Sampler (ELDS), has been developed to fill a gap in passive sampling for near-field particle emissions. The sampler can be configured in several ways: with a protective hood for outdoor sampling, without a protective hood, and as a dust plate. The sampler both collects mass and allows for the measurement of an environmental contaminant. The ELDS can be used indoors and outdoors in a variety of configurations to suit the user's needs. (Einstein, et al., 2012). The Mainelis group also developed a personal sampling surrogate: the Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler to better estimate pretoddler exposure to allergens, mold spores, and endotoxin. During sampling, PIPER simulates the activity patterns, speed of motion, and the height of the breathing zones of young children, and mechanically resuspends the deposited dust just as a young child does during running and crawling (Wang et al., 2012). Outputs: Participants at the 2012 NC1187 Annual Meeting reported on their research progress. These included: Harshs work on colloidal transport at both micro- and field lysimeter scale; separate studies by Smucker and Anderson groups to characterize soil pores with x-ray tomography and estimate transport parameters. Dr. Anderson found good agreement with macroscopic retardation factors determined by conventional column experiments. The immediate application is to fluid and solute transport. Dr. Smucker was able to interface tortuosity determineation at the microscale with transport modeling (HYDRUS 3D). In addition to transport, Smuckers group is interested in carbon sequestration, bacteria transport, effects of long-term management, and use of polyethylene glycol for water retention in relation to soil pore structure. Dr. Hettiarachchi has been using x-ray absorption spectroscopy to examine carbon sequestration as a function of soil management and the role of colloid transport and chemical speciation on contaminant transport and remediation in mining areas. Carbon sequestration under different management regimes is also under investigation by Dr. Sparks, working from the aspect of C-Fe interactions. He is also characterizing airborne particulates from poultry waste and finding As, Fe, and Mn with evidence of methylation on the particles. Bacteria were seen on the particles with confocal laser microsocopy. In collaboration with Dr. Markus Flury, Jim Harsh has conducted research on the effect of transient flow on colloid detachment and transport in the vadose zone. Colloids attached to glass capillary tube walls were subjected to incremental water flow after mapping colloid distribution with confocal microscopy. Detachment was quantified following advancing and receding air-water interfaces and we found that detachment was significant following an advancing but not receding interfaces. Results could be explained by capillary forces acting at the air-water interface. Following our publication last year in Langmuir a second publication was submitted in 2013 applying both theory and experiment to non-spherical particles. In a field study, we determined the transport of europium hydroxycarbonate particles in lysimeters filled with material from the Hanford Formation at the Hanford Site in Central Washington. Under transient flow conditions from both irrigated and natural rainfall water additions, a small number of colloids were detected at over 2 m depth after only 2.5 months and 20 mm cumulative rainfall. Over longer time periods colloid velocities were in line with average recharge rates at the site. Most particles remained in the top 30 cm of the lysimeters. These results were consistent with the detachment phenomena in capillary tubes described above. A manuscript has been submitted to and reviewed twice by ES&T and the final revision submitted. Another lysimeter study is in process using an undisturbed Hanford Formation sediment core (50 cm i.d; 59.5 cm depth) and conducted under laboratory conditions. At a solution application rate of 18 mm per year, native colloid (silicates, aluminosilicates, and oxides) transport has been quantified in the outflow for 5.3 years so far. Only 0.5% of the total dispersible particles were recovered in the outflow. Fitted colloid release parameters were six to seven orders of magnitude smaller than ones determined at lower flow rates in disturbed columns. Nevertheless, results show that continuous mobilization of colloids does occur even under low recharge rates and water contents typical of a semi-arid environment. One manuscript has been submitted to Water Resources Research. Dr. Harsh also collaborated with Drs. Seyoum Gebrimariam, Marc Beutel, Markus Flury, and David Yonge in a study of chlorpyrifos sorption hysteresis in soils. At environmentally relevant concentrations, chlorpyrifos exhibited strong adsorption/desorption and hysteresis that correlated significantly with organic matter content. Chlorpyrifos desorption was biphasic and followed a falling desorption isotherm with zero intercept. The isotherm was estimated using a memory-dependent mathematical model. The labile component comprised 18 to 28% of the original solid-phase concentration, and the residue was predicted to slowly partition to the aqueous phase implying long-term desorption from contaminated soils or sediments. The mechanism of hysteresis and biphasic desorption was explained by the unfavorable thermodynamic energy landscape leading to limitation of diffusivity of water molecules through the strongly hydrophobic domain of soils and sediments. Results indicate that contaminated soils and sediments could serve as a secondary long-term source of pollution. Long-term desorption may also explain the detection of chlorpyrifos and other hydrophobic organic compounds in aquatic systems far from application sites, an observation that contradicts conventional transport predictions. Two manuscripts were published in 2012. Dr. Steven Anderson has introduced computed tomography (CT) measurement systems as a method to measure fluid transport at the macropore-scale to estimate transport parameters. The objective was to use x-ray CT methods to measure transport of iodophenol solution in geomedia columns and estimate spatial distributions of chemical retardation. An initial CT-measured breakthrough curve experiment was conducted with potassium iodide to spatially estimate pore-water velocity and dispersivity in the geomedia core, followed with a transport experiment with iodophenol to estimate the spatial distribution of chemical retardation. A geomedia core was removed from the surface horizon of Sarpy loamy sand (Typic Udispamment). Spatial distributions followed a fractal pattern with dimensional values similar among pore-water velocity, dispersivity and retardation coefficient parameters. The retardation coefficient estimated using CT methods was similar compared to the dynamic fluid experiment, thus indicating this new method may be appropriate for pollutant transport analysis. This study illustrates that the CT method is useful for evaluating solute transport on a macropore-scale for porous materials. Information on chemical adsorption during actively flowing water transport will contribute to improved modeling of solute transport for environmental sites. Eight publications resulted from this project. Drs. Alexandra Kravchenkos and Alvin Smuckers groups at Michigan State University are investigating the role of intra-aggregate pores in controlling soil processes on a micro-scale. Differences in parent materials, pedogenic processes, land use, and management practices can have a substantial effect on their characteristics. The goal of this study is to examine intra-aggregate pore characteristics using X-ray computed microtomography (mu CT) images in soils of two contrasting parent materials and of contrasting land use and management. In addition, to quantify pore characteristics in aggregate exterior and interior layers we have developed an approach for aggregate boundary delineation in mu CT images. Soil aggregates from a Hapludalf under Long Term Ecological Research conventional tillage treatment (LTER-CT) and native succession vegetation treatment (LTER-NS) in southwest Michigan, and from an Ustochrept under native succession vegetation and bare soil in northeast China were used. The LTER-CT aggregates had significantly greater macro-porosity (>14.6 mu m in diameter) than those of LTER-NS. The LTER-NS aggregates had more large pores (>97.5 mu m) and more small pores (<15 mu m) than LTER-CT aggregates, while more medium size pores (37.5-97.5 mu m) were found in LTER-CT aggregates. Greater abundance of medium sized pores in LTER-CT aggregates could be the cause of their reported lower stability and higher macro-aggregate turnover rate. The differences in pore size distributions between LTER-CT and LTER-NS were more pronounced in the aggregate interiors, as compared to the exterior layers. In aggregates from both studied soils large pores tended to prevail in the aggregate interiors while medium size pores (37.5-97.5 mu m) were more abundant in the aggregate exteriors. There were three publications. Dr. Daniel Strawn and his associate Dr. Leslie Baker used Fe K-edge X-ray absorption fine structure (XAFS) spectroscopy to examine local molecular structure and cation distribution in the natural nanosilicate hisingerite and synthetic nanoaluminosilicate allophane in comparison to crystalline counterparts. From XAFS interpretations, the following structural information was concluded: (1) Fe in both hisingerite and allophane is present in well-defined octahedral sites, (2) less long-range structure is observed in hisingerite and allophane than in smectites, and (3) Fe in allophane is present in small clusters in the octahedral sheet. The best fit for hisingerite was obtained using a 1:1 model structure rather than a 2:1 model, supporting a description of it as a ferric halloysite-type structure. Allophane could not be fit using paths based on Fe-substituted proto-imogolite nanospherical models but was successfully fit using a montmorillonite structure. Published models of nanospherical particles suggest backscattering path lengths in allophane and hisingerite should be shortened compared to clay minerals; however, no such shortening was observed, suggesting the nanosphere model does not accurately describe the local atomic structure of these Fe-substituted minerals. Dr. Strawns group published three manuscripts in 2012. Dr. Toner in her last year as a participant in NC-1187 has studied deep-sea hydrothermal plume particles known to sequester seawater trace elements and influence ocean-scale biogeochemical budgets. Suspended particulate material was collected from a non-buoyant hydrothermal plume. Analyses included elemental composition with X-ray fluorescence, speciation of Fe, S, and C by 1s X-ray absorption near edge structure spectroscopy, and crystallography with X-ray diffraction. Particle aggregates were common and composed of minerals embedded in an organic matrix. Over 20 different minerals were observed, nine of which were either unpredicted by thermodynamic modeling or had no close match in the thermodynamic database. The organic matrix was: (1) always associated with minerals, (2) composed of biomolecules, and (3) rich in S. These results indicate that particle aggregation with organic material is prevalent in dispersing hydrothermal plume fluxes, as well as in sinking particulate matter at this site. Particle aggregation and organic coatings can influence the reactivity, transport, and residence time of hydrothermal particles in the water column. Thus a biogeochemical approach to particulate analysis is critical to understanding the net effect of hydrothermal fluxes on ocean and sedimentary trace element budgets. Five papers were published overall. Dr. Ganga Hettiarachchi and her collaborators have examined the ability of high-Fe biosolids-based composts to reduce the bioaccessibility of Pb and As in contaminated orchard soils in Washington State. The composts were amended with Fe using Fe powder, waste treatment residuals (WTR), or Fe-chloride salt and applied at different rates. Bioaccessibility was assessed with an in vitro assay and chemical speciation with micro-X-ray fluorescence (XRF) and ¼-XANES. Results showed that the ability to reduce bioaccessability depended on Fe source and reduction of Pb bioaccessibility was more consistent than for As. Another study used ¼-EXAFS, ¼-XRF, and ¼-XRD to characterize Zn speciation in soil contaminated with Pb and Zn from smelters and amended with phosphate sources. Phosphate rock (PR), triple super phosphate (TSP), monoammonium phosphate (MAP), and fluid ammonium polyphosphate induced Zn phosphate formation, but phosphoric acid increased Zn solubility by lowering pH. Hettiarchchi and colleagues also characterized Ca, Fe, Mn, and Zn speciation within and around soil pores at an Alfisol B-horizon/E-horizon interface using ¼-XRF and ¼-EXAFS. While only Ca was found in the pore, Fe- and Mn- were associated with each other and around the pore. Zn occurred in association with carbonate, sulfate, and silicate. Her group also determined differences P speciation in agricultural soils as a function of time and P source and application. Deep banding with liquid sources favored P adsorption and greater lability. Formation of Fe-associated P occurred in broadcast treatments and Ca-phosphate precipitates increased with time. She also participated in a study of how zinc oxide nanoparticle coating of macronutrient fertilizers influence dissolution rates, Five publications came from this group. Joseph Stucki and others at the University of Illinois studied the ability of polydiallyldimethylammonium-exchanged ferruginous smectites to adsorb and abiotically reduce nitrate. The positively-charged clay was able to adsorb nitrate and when Fe in the smectites was reduced to Fe(II), able to reduce nitrate to nitrite. One publication resulted. Dr. Gediminas Mainelis and coworkers have been working to develop samplers for airborne particulates that simulate uptake by humans and that allow for characterization of collected particles by XRF. Particle size and chemical measurements with TEM, XRF, and laser diffraction have allowed them to determine the effect of particle size on inhalation and region of deposition. They have also quantified and located nanoparticles from cosmetics and found that predominant deposition of nanomaterial(s) can occur in the tracheobronchial and head airways, not in the alveolar region as would be expected based on the size of primary nanoparticles. This could potentially lead to different health effects than expected based on the current understanding of nano-particle behavior and toxicology studies for the alveolar region. Activities: Stephen Anderson was a co-organizer of a symposium entitled Tomography and Imaging for Soil-Water-Root Processes at the International Meeting of the SSSA, October, 2012 in Cincinnati, Ohio. This symposium provided an update of tomography and imaging methods for evaluation of soils. Specific methods discussed included x-ray computed tomography, synchrotron microtomography, neutron imaging, geophysical imaging tools, and other tomography techniques for evaluating soil and root systems. These presentations provided a unique collection of topics exploring applications of imaging and tomography systems for soil science. Several new procedures and applications have been developed over the past two decades that were discussed. Milestones: The Bouyoucos Conference did not result in specific publications it did act as a springboard for this years symposium described in the paragraph above. In addition, it started the discussion for multi-investigator proposals within the group that are continuing. Finally, some users are beginning to use the Canadian Light Source in Saskatoon reporting that it is not heavily used. We will explore further its capabilities and the potential for use by members of our group and others.

Baker, L.L., W.C. Rember, K.F. Sprenke and D.G. Strawn. 2012. Celadonite in continental flood basalts of the Columbia River Basalt Group. American Mineralogist 97: 1284-1290. doi:10.2138/am.2012.4129. Baker, L.L. and D.G. Strawn. 2012. Fe K-edge XAFS spectra of phyllosilicates of varying crystallinity. Physics and Chemistry of Minerals 39: 675-684. doi:10.1007/s00269-012- 0521-0. Bangira, C., Y. Deng, R.H. Loeppert, C.T. Hallmark and J.W. Stucki. 2011. Soil Mineral Composition in Contrasting Climatic Regions of the Great Dyke, Zimbabwe. Soil Science Society of America Journal 75: 2367-2378. doi:10.2136/sssaj2011.0134. Bloom, P.R., G.W. Rehm, J.A. Lamb and A.J. Scobbie. 2011. Soil Nitrate is a Causative Factor in Iron Deficiency Chlorosis in Soybeans. Soil Science Society of America Journal 75: 2233-2241. doi:10.2136/sssaj2010.0391. Breier, J.A., B.M. Toner, S.C. Fakra, M.A. Marcus, S.N. White, A.M. Thurnherr, et al. 2012. Sulfur, sulfides, oxides and organic matter aggregated in submarine hydrothermal plumes at 9 degrees 50 ' N East Pacific Rise. Geochimica Et Cosmochimica Acta 88: 216-236. doi:10.1016/j.gca.2012.04.003. Brown, S.L., I. Clausen, M.A. Chappell, K.G. Scheckel, M. Newville and G.M. Hettiarachchi. 2012. High-Iron Biosolids Compost-Induced Changes in Lead and Arsenic Speciation and Bioaccessibility in Co-contaminated Soils. Journal of Environmental Quality 41: 1612-1622. doi:10.2134/jeq2011.0297. Diehl, J., S.E. Johnson, K. Xia, A. West and L. Tomanek. 2012. The distribution of 4- nonylphenol in marine organisms of North American Pacific Coast estuaries. Chemosphere 87: 490-497. doi:10.1016/j.chemosphere.2011.12.040. Dong, H. and J.W. Stucki. 2011. ADVANCES IN CLAY SCIENCE IN CHINA. Clays and Clay Minerals 59: 435-437. doi:10.1346/ccmn.2011.0590500. Edwards, K.J., B.T. Glazer, O.J. Rouxel, W. Bach, D. Emerson, R.E. Davis, et al. 2011. Ultradiffuse hydrothermal venting supports Fe-oxidizing bacteria and massive umber deposition at 5000 m off Hawaii. Isme Journal 5: 1748-1758. doi:10.1038/ismej.2011.48. Einstein, S.A., C.-H. Yu, G. Mainelis, L.C. Chen, C.P. Weisel and P.J. Lioy. 2012. Design and validation of a passive deposition sampler. Journal of Environmental Monitoring 14: 2411-2420. doi:10.1039/c2em30174a. Fortuna, A.-M., C.W. Honeycutt, G. Vandemark, T.S. Griffin, R.P. Larkin, Z. He, et al. 2012. Links among Nitrification, Nitrifier Communities, and Edaphic Properties in Contrasting Soils Receiving Dairy Slurry. Journal of Environmental Quality 41: 262-272. doi:10.2134/jeq2011.0202. Han, T. and G. Mainelis. 2012. Investigation of inherent and latent internal losses in liquid-based bioaerosol samplers. Journal of Aerosol Science 45: 58-68. doi:10.1016/j.jaerosci.2011.11.001. Holden, J.F., J.A. Breier, K.L. Rogers, M.D. Schulte and B.M. Toner. 2012. Biogeochemical Processes at Hydrothermal Vents Microbes and Minerals, Bioenergetics, and Carbon Fluxes. Oceanography 25: 196-208. Ippolito, J.A., D.G. Strawn, K.G. Scheckel, J.M. Novak, M. Ahmedna and M.A.S. Niandou. 2012. Macroscopic and Molecular Investigations of Copper Sorption by a Steam- Activated Biochar. Journal of Environmental Quality 41: 1150-1156. doi:10.2134/jeq2011.0113. Jassogne, L., G. Hettiarachchi, A. McNeill and D. Chittleborough. 2012. Characterising the chemistry of micropores in a sodic soil with strong texture-contrast using synchrotron Xray techniques and LA-ICP-MS. Soil Research 50: 424-435. doi:10.1071/sr11312. Jones, L.C., B.J. Lafferty and D.L. Sparks. 2012. Additive and Competitive Effects of Bacteria and Mn Oxides on Arsenite Oxidation Kinetics. Environmental Science & Technology 46: 6548-6555. doi:10.1021/es204252f. Kelly, J.G., F.X. Han, Y. Su, Y. Xia, V. Philips, Z. Shi, et al. 2012. Rapid Determination of Mercury in Contaminated Soil and Plant Samples Using Portable Mercury Direct Analyzer without Sample Preparation, a Comparative Study. Water Air and Soil Pollution 223: 2361-2371. doi:10.1007/s11270-011-1030-3. Khaokaew, S., G. Landrot, R.L. Chaney, K. Pandya and D.L. Sparks. 2012. Speciation and Release Kinetics of Zinc in Contaminated Paddy Soils. Environmental Science & Technology 46: 3957-3963. doi:10.1021/es204007t. Kwon, J.-W. and K. Xia. 2012. Fate of triclosan and triclocarban in soil columns with and without biosolids surface application. Environmental Toxicology and Chemistry 31: 262- 269. doi:10.1002/etc.1703. Lafferty, B.J., M. Ginder-Vogel and D.L. Sparks. 2011. Arsenite Oxidation by a Poorly- Crystalline Manganese Oxide. 3. Arsenic and Manganese Desorption. Environmental Science & Technology 45: 9218-9223. doi:10.1021/es201281u. Landrot, G., R. Tappero, S.M. Webb and D.L. Sparks. 2012. Arsenic and chromium speciation in an urban contaminated soil. Chemosphere 88: 1196-1201. doi:10.1016/j.chemosphere.2012.03.069. Li, T., Z. Xu, X. Han, X. Yang and D.L. Sparks. 2012. Characterization of dissolved organic matter in the rhizosphere of hyperaccumulator Sedum alfredii and its effect on the mobility of zinc. Chemosphere 88: 570-576. doi:10.1016/j.chemosphere.2012.03.031. Livi, K.J.T., B. Lafferty, M. Zhu, S. Zhang, A.-C. Gaillot and D.L. Sparks. 2012. Electron Energy-Loss Safe-Dose Limits for Manganese Valence Measurements in Environmentally Relevant Manganese Oxides. Environmental Science & Technology 46: 970-976. doi:10.1021/es203516h. Maruya, K.A., D.E. Vidal-Dorsch, S.M. Bay, J.W. Kwon, K. Xia and K.L. Armbrust. 2012. Organic contaminants of emerging concern in sediments and flatfish collected near outfalls discharging treated wastewater effluent to the Southern California Bight. Environmental Toxicology and Chemistry 31: 2683-2688. doi:10.1002/etc.2003. Miguel, C.S., D. Gimenez, U. Krogmann and S.W. Yoon. 2012. Impact of land application of cranberry processing residuals, leaves and biosolids pellets on a sandy loam soil. Applied Soil Ecology 53: 31-38. doi:10.1016/j.apsoil.2011.11.001. Milani, N., M.J. McLaughlin, S.P. Stacey, J.K. Kirby, G.M. Hettiarachchi, D.G. Beak, et al. 2012. Dissolution Kinetics of Macronutrient Fertilizers Coated with Manufactured Zinc Oxide Nanoparticles. Journal of Agricultural and Food Chemistry 60: 3991-3998. doi:10.1021/jf205191y. Munoz, J.D. and A. Kravchenko. 2011. Soil carbon mapping using on-the-go near infrared spectroscopy, topography and aerial photographs. Geoderma 166: 102-110. doi:10.1016/j.geoderma.2011.07.017. Nazarenko, Y., H. Zhen, T. Han, P.J. Lioy and G. Mainelis. 2012. Potential for Inhalation Exposure to Engineered Nanoparticles from Nanotechnology-Based Cosmetic Powders. Environmental Health Perspectives 120: 885-892. doi:10.1289/ehp.1104350. Parsekian, A.D., L. Slater and D. Gimenez. 2012. Application of ground-penetrating radar to measure near-saturation soil water content in peat soils. Water Resources Research 48. doi:10.1029/2011wr011303. Premarathna, H.M.P.L., M.J. McLaughlin, J.K. Kirby, G.M. Hettiarachchi and S. Stacey. 2012. Influence of submergence and subsequent drainage on the partitioning and lability of added selenium fertilizers in a sulphur-containing Fluvisol. European Journal of Soil Science 63: 514-522. doi:10.1111/j.1365-2389.2012.01462.x. Premarathna, L., M.J. McLaughlin, J.K. Kirby, G.M. Hettiarachchi, S. Stacey and D.J. Chittleborough. 2012. Selenate-Enriched Urea Granules Are a Highly Effective Fertilizer for Selenium Biofortification of Paddy Rice Grain. Journal of Agricultural and Food Chemistry 60: 6037-6044. doi:10.1021/jf3005788. Shafer, M.M., B.M. Toner, J.T. Oyerdier, J.J. Schauer, S.C. Fakra, S. Hu, et al. 2012. Chemical Speciation of Vanadium in Particulate Matter Emitted from Diesel Vehicles and Urban Atmospheric Aerosols. Environmental Science & Technology 46: 189-195. doi:10.1021/es200463c. Shi, Z., E. Peltier and D.L. Sparks. 2012. Kinetics of Ni Sorption in Soils: Roles of Soil Organic Matter and Ni Precipitation. Environmental Science & Technology 46: 2212-2219. doi:10.1021/es202376c. Strawn, D.G., P.J. Hickey, P.A. McDaniel and L.L. Baker. 2012. Distribution of As, Cd, Pb, and Zn in redox features of mine-waste impacted wetland soils. Journal of Soils and Sediments 12: 1100-1110. doi:10.1007/s11368-012-0543-8. Subroy, V., D. Gimenez, D. Hirmas and P. Takhistov. 2012. On Determining Soil Aggregate Bulk Density by Displacement in Two Immiscible Liquids. Soil Science Society of America Journal 76: 1212-1216. doi:10.2136/sssaj2011.0333. Sylvan, J.B., B.M. Toner and K.J. Edwards. 2012. Life and Death of Deep-Sea Vents: Bacterial Diversity and Ecosystem Succession on Inactive Hydrothermal Sulfides. Mbio 3. doi:10.1128/mBio.00279-11. Tamir, G., M. Shenker, H. Heller, P.R. Bloom, P. Fine and A. Bar-Tal. 2012. Dissolution and Re-crystallization Processes of Active Calcium Carbonate in Soil Developed on Tufa. Soil Science Society of America Journal 76: 1606-1613. doi:10.2136/sssaj2012.0041. Toner, B.M., M.A. Marcus, K.J. Edwards, O. Rouxel and C.R. German. 2012. Measuring the Form of Iron in Hydrothermal Plume Particles. Oceanography 25: 209-212. Wang, W., A.N. Kravchenko, A.J.M. Smucker, W. Liang and M.L. Rivers. 2012. Intra-aggregate Pore Characteristics: X-ray Computed Microtomography Analysis. Soil Science Society of America Journal 76: 1159-1171. doi:10.2136/sssaj2011.0281. Wang, W., A.N. Kravchenko, A.J.M. Smucker, W. Liang and M.L. Rivers. 2012. Intra-aggregate Pore Characteristics: X-ray Computed Microtomography Analysis. Soil Science Society of America Journal 76: 1159-1171. doi:10.2136/sssaj2011.0281. Wang, Z., S.L. Shalat, K. Black, P.J. Lioy, A.A. Stambler, O.H. Emoekpere, et al. 2012. Use of a robotic sampling platform to assess young children's exposure to indoor bioaerosols. Indoor Air 22: 159-169. doi:10.1111/j.1600-0668.2011.00749.x. Xia, K., G. Hagood, C. Childers, J. Atkins, B. Rogers, L. Ware, et al. 2012. Polycyclic Aromatic Hydrocarbons (PAHs) in Mississippi Seafood from Areas Affected by the Deepwater Horizon Oil Spill. Environmental Science & Technology 46: 5310-5318. doi:10.1021/es2042433. Yoon, S.W. and D. Gimenez. 2012. Entropy Characterization of Soil Pore Systems Derived From Soil-Water Retention Curves. Soil Science 177: 361-368. doi:10.1097/SS.0b013e318256ba1c. Zhu, M., C.L. Farrow, J.E. Post, K.J.T. Livi, S.J.L. Billinge, M. Ginder-Vogel, et al. 2012. Structural study of biotic and abiotic poorly-crystalline manganese oxides using atomic pair distribution function analysis. Geochimica Et Cosmochimica Acta 81: 39-55. doi:10.1016/j.gca.2011.12.006.