@article{gillispie_matteson_duckworth_neumann_phen_polizzotto_2019, title={Chemical variability of sediment and groundwater in a Pleistocene aquifer of Cambodia: Implications for arsenic pollution potential}, volume={245}, ISSN={["1872-9533"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85057339109&partnerID=MN8TOARS}, DOI={10.1016/j.gca.2018.11.008}, abstractNote={Low-arsenic (As) groundwater from Pleistocene aquifers is vulnerable to future geogenic and allogenic arsenic pollution in South and Southeast Asia, threatening the millions who use it as a “safe source” of drinking and irrigation water. The abundance and chemical reactivity of iron and manganese oxides within these aquifer sediments control the occurrence and mobility of arsenic. In the present study, sediment samples varying in As, Fe, and Mn content were obtained from a Pleistocene aquifer in the Kandal Province of Cambodia. Laboratory and spectroscopic characterization of the sediment combined with groundwater analyses revealed that the availability and abundance of sedimentary As varied across a Pleistocene aquifer from the pore to field scales. Concentrations of sediment As (0.47–7 μg/g) correlated more strongly with Fe (R2 > 0.66) than with Mn (R2 > 0.35) concentrations in sediment well cuttings and tended to peak between 10 and 15 m. Chemical extractions and X-ray adsorption spectroscopy indicated the majority of As was strongly adsorbed to aquifer sediments or coprecipitated in oxides in the form of As(V) but that As(III) could be found in sediment microenvironments across the aquifer. Groundwater chemistry and Mn mineralogy indicated that the Pleistocene aquifer was suboxic, with average dissolved oxygen of 1.9 mg/L (±0.9 mg/L), redox potential of 0.155 V (±0.097 V), and abundant Mn(III/IV) oxide minerals. According to our results, allogenic As transport and geogenic As release will likely be dictated by localized geochemical processes that vary over a range of scales. Collectively, the specific Fe and Mn mineralogy and content within aquifers will ultimately govern As pollution potential, so understanding their multi-scale distributions and variability is essential for better predicting future risks to well-water quality in currently low-As aquifers.}, journal={GEOCHIMICA ET COSMOCHIMICA ACTA}, author={Gillispie, Elizabeth C. and Matteson, Audrey R. and Duckworth, Owen W. and Neumann, Rebecca B. and Phen, Nuon and Polizzotto, Matthew L.}, year={2019}, month={Jan}, pages={441–458} }
 @article{matteson_graves_hall_kuy_polizzotto_2016, title={Fecal contamination and Microcystis in drinking-water sources of rural Cambodia using PCR and culture-based methods}, volume={6}, ISSN={["2043-9083"]}, DOI={10.2166/washdev.2016.136}, abstractNote={Rural communities within low-income countries frequently rely on a range of drinking-water sources, and each water source varies in its potential for biological contamination. The extent and source of biological contamination in primary drinking sources within Kien Svay, Kandal, Cambodia, were determined by fecal indicator bacteria (FIB) measurements, 16S rDNA genetic markers for human and bovine fecal Bacteroides, presence of the bloom-forming Microcystis species, and the microcystin toxin mcyD gene marker. Thirteen wells, 11 rain barrels, 10 surface-water sites, and five sediment samples were examined during the dry and wet seasons. Surface water was commonly contaminated with FIB, with up to 1.02 × 105Enterococcus sp., 6.13 × 104E. coli, and 2.91 × 104 total coliforms per 100 mL of water. Human and bovine Bacteroides were detected in 100 and 90% of the surface water samples, respectively. Concentrations of FIB in rain-barrels varied by site, however 91% contained human Bacteroides. Microcystis cells were found in 90% of surface water sites, with many also containing microcystin gene mcyD, representing the first report of microcystin-producing cyanobacteria in surface waters of Cambodia. The study results show that many potential drinking-water sources in Cambodia contain harmful bacterial and algal contaminants, and care should be taken when selecting and monitoring water options.}, number={3}, journal={JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT}, author={Matteson, Audrey R. and Graves, Alexandria K. and Hall, Ann M. and Kuy, Dina and Polizzotto, Matthew L.}, year={2016}, month={Sep}, pages={353–361} }
 @article{mahoney_gannon_jeffries_matteson_polizzotto_2015, title={Management considerations to minimize environmental impacts of arsenic following monosodium methylarsenate (MSMA) applications to turfgrass}, volume={150}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2014.12.027}, abstractNote={Monosodium methylarsenate (MSMA) is an organic arsenical herbicide currently utilized in turfgrass and cotton systems. In recent years, concerns over adverse impacts of arsenic (As) from MSMA applications have emerged; however, little research has been conducted in controlled field experiments using typical management practices. To address this knowledge gap, a field lysimeter experiment was conducted during 2012-2013 to determine the fate of As following MSMA applications to a bareground and an established turfgrass system. Arsenic concentrations in soil, porewater, and aboveground vegetation, were measured through one yr after treatment. Aboveground vegetation As concentration was increased compared to nontreated through 120 d after initial treatment (DAIT). In both systems, increased soil As concentrations were observed at 0-4 cm at 30 and 120 DAIT and 0-8 cm at 60 and 365 DAIT, suggesting that As was bound in shallow soil depths. Porewater As concentrations in MSMA-treated lysimeters from a 30-cm depth (22.0-83.8 μg L(-1)) were greater than those at 76-cm depth (0.4-5.1 μg L(-1)). These results were combined with previous research to devise management considerations in systems where MSMA is utilized. MSMA should not be applied if rainfall is forecasted within 7 DAIT and/or in areas with shallow water tables. Further, disposing of MSMA-treated turfgrass aboveground vegetation in a confined area - a common management practice for turfgrass clippings - may be of concern due to As release to surface water or groundwater as the vegetation decomposes. Finally, long-term MSMA use may cause soil As accumulation and thus downward migration of As over time; therefore, MSMA should be used in rotation with other herbicides.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Mahoney, Denis J. and Gannon, Travis W. and Jeffries, Matthew D. and Matteson, Audrey R. and Polizzotto, Matthew L.}, year={2015}, month={Mar}, pages={444–450} }
 @article{matteson_gannon_jeffries_haines_lewis_polizzotto_2014, title={Arsenic Retention in Foliage and Soil after Monosodium Methyl Arsenate (MSMA) Application to Turfgrass}, volume={43}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2013.07.0268}, abstractNote={Monosodium methyl arsenate (MSMA) is a commonly used herbicide for weed control in turfgrass systems. There is concern that arsenic from applied MSMA could leach to groundwater or run off into surface water, thereby threatening human and ecosystem health. The USEPA has proposed a phase-out of the herbicide but is seeking additional research about the toxicity and environmental impacts of MSMA before establishing a final ruling. Little research has systematically investigated MSMA in field-based settings; instead, risks have been inferred from isolated field measurements or model-system studies. Accordingly, the overall goal of this study was to quantify the fate of arsenic after MSMA application to a managed turfgrass system. After MSMA application to turfgrass-covered and bareground lysimeters, the majority of arsenic was retained in turfgrass foliage and soils throughout year-long experiments, with 50 to 101% of the applied arsenic recovered in turfgrass systems and 55 to 66% recovered in bareground systems. Dissolved arsenic concentrations from 76.2-cm-depth pore water in the MSMA-treated soils were consistently <2 μg L, indistinguishable from background concentrations. As measured by adsorption isotherm experiments, MSMA retention by the sandy soil from our field site was markedly less than retention by a washed sand and a clay loam. Collectively, these results suggest that under aerobic conditions, minimal arsenic leaching to groundwater would occur after a typical application of MSMA to turfgrass. However, repeated MSMA application may pose environmental risks. Additional work is needed to examine arsenic cycling near the soil surface and to define arsenic speciation changes under different soil conditions.}, number={1}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Matteson, Audrey R. and Gannon, Travis W. and Jeffries, Matthew D. and Haines, Stephanie and Lewis, Dustin F. and Polizzotto, Matthew L.}, year={2014}, pages={379–388} }
 @article{matteson_mahoney_gannon_polizzotto_2014, title={Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation}, ISSN={["1940-087X"]}, DOI={10.3791/51862}, abstractNote={Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment.}, number={89}, journal={JOVE-JOURNAL OF VISUALIZED EXPERIMENTS}, author={Matteson, Audrey R. and Mahoney, Denis J. and Gannon, Travis W. and Polizzotto, Matthew L.}, year={2014}, month={Jul} }
 @article{polizzotto_lineberger_matteson_neumann_badruzzaman_ali_2013, title={Arsenic transport in irrigation water across rice-field soils in Bangladesh}, volume={179}, ISSN={["0269-7491"]}, DOI={10.1016/j.envpol.2013.04.025}, abstractNote={Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes.}, journal={ENVIRONMENTAL POLLUTION}, author={Polizzotto, Matthew L. and Lineberger, Ethan M. and Matteson, Audrey R. and Neumann, Rebecca B. and Badruzzaman, A. Borhan M. and Ali, M. Ashraf}, year={2013}, month={Aug}, pages={210–217} }