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If not managed properly, modern agricultural practices can alter surface and groundwater quality and drinking water resources resulting in potential negative effects on aquatic and terrestrial ecosystems. Exposure to agriculturally derived contaminant mixtures has the potential to alter habitat quality and negatively affect fish and other aquatic organisms. Implementation of conservation practices focused on improving water quality continues to increase particularly in agricultural landscapes throughout the United States. The goal of this study was to determine the consequences of land management actions on the primary drivers of contaminant mixtures in five agricultural watersheds in the Chesapeake Bay, the largest watershed of the Atlantic Seaboard in North America where fish health issues have been documented for two decades. Surface water was collected and analyzed for 301 organic contaminants to determine the benefits of implemented best management practices (BMPs) designed to reduce nutrients and sediment to streams in also reducing contaminants in surface waters. Of the contaminants measured, herbicides (atrazine, metolachlor), phytoestrogens (formononetin, genistein, equol), cholesterol and total estrogenicity (indicator of estrogenic response) were detected frequently enough to statistically compare to seasonal flow effects, landscape variables and BMP intensity. Contaminant concentrations were often positively correlated with seasonal stream flow, although the magnitude of this effect varied by contaminant across seasons and sites. Land-use and other less utilized landscape variables including biosolids, manure and pesticide application and percent phytoestrogen producing crops were inversely related with site-average contaminant concentrations. Increased BMP intensity was negatively related to contaminant concentrations indicating potential co-benefits of BMPs for contaminant reduction in the studied watersheds. The information gained from this study will help prioritize ecologically relevant contaminant mixtures for monitoring and contributes to understanding the benefits of BMPs on improving surface water quality to better manage living resources in agricultural landscapes inside and outside the Chesapeake Bay watershed.

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Long Island, New York, has a mix of urban/suburban to agricultural/horticultural land use and nearly 3 million residents that rely on a sole-source aquifer for drinking water. The analysis of shallow groundwater (<40 m below land surface) collected from 54 monitoring wells across Long Island detected 53 pesticides or pesticide degradates. Maximum concentrations for individual pesticides or pesticide degradates ranged from 3 to 368,000 ng/L. The highest concentrations and most frequent pesticide detections occurred in samples collected from the pesticide management (PM) network, set in an agricultural/horticultural area in eastern Long Island with coordinated pesticide management by state and local agencies. The other two networks (Suffolk and Nassau/Queens) were set in suburban and urban areas, respectively, and had less frequent detections and lower pesticide concentrations than the PM network. Pesticide detections and concentration patterns (herbicide, insecticide, or fungicide) differed among the three networks revealing broad differences in land use. The predominance of fungicides metalaxyl, 1H-1,2,4-triazole (propiconazole/myclobutanil degradate), and 4-hydroxychlorothalonil (HCTL, chlorothalonil degradate) in samples from the PM network reflects their intensive use in agricultural settings. Total fungicide concentrations in the PM network ranged from <10 to >300,000 ng/L. The widespread detection of imidacloprid and triazine herbicides, simazine and atrazine, reveal a mixture of current and past use pesticides across the Long Island region. Low concentrations (<200 ng/L) of the triazines in the Suffolk and Nassau/Queens networks may reflect a change in land use and application. Acetanilide herbicides and aldicarb have been discontinued for 20 and 40 years, respectively, yet the concentrations of their degradates were among the highest observed in this study. Acetanilide (total concentrations up to 10,000 ng/L) and aldicarb degradates (up to 270 ng/L) are present in the PM network at much lower concentrations than previous Long Island studies and reflect changes in agricultural practices and pesticide management.

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Groundwater discharge zones in streams are important habitats for aquatic organisms. The use of discharge zones for thermal refuge and spawning by fish and other biota renders them susceptible to potential focused discharge of groundwater contamination. Currently, there is a paucity of information about discharge zones as a potential exposure pathway of chemicals to stream ecosystems. Using thermal mapping technologies to locate groundwater discharges, shallow groundwater and surface water from three rivers in the Chesapeake Bay Watershed, USA were analyzed for phytoestrogens, pesticides and their degradates, steroid hormones, sterols and bisphenol A. A Bayesian censored regression model was used to compare groundwater and surface water chemical concentrations. The most frequently detected chemicals in both ground and surface water were the phytoestrogens genistein (79%) and formononetin (55%), the herbicides metolachlor (50%) and atrazine (74%), and the sterol cholesterol (88%). There was evidence suggesting groundwater discharge zones could be a unique exposure pathway of chemicals to surface water systems, in our case, metolachlor sulfonic acid (posterior mean concentration = 150 ng/L in groundwater and 4.6 ng/L in surface water). Our study also demonstrated heterogeneity of chemical concentration in groundwater discharge zones within a stream for the phytoestrogen formononetin, the herbicides metolachlor and atrazine, and cholesterol. Results support the hypothesis that discharge zones are an important source of exposure of phytoestrogens and herbicides to aquatic organisms. To manage critical resources within the Chesapeake Bay Watershed, more work is needed to characterize exposure in discharge zones more broadly across time and space.

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Investigating the spatiotemporal dynamics of contaminants in surface water is crucial to better understand how introduced chemicals are interacting with and potentially influencing aquatic organisms and environments. Within the Chesapeake Bay Watershed, United States, there are concerns about the potential role of contaminant exposure on fish health. Evidence suggests that exposure to contaminants in surface water is causing immunosuppression and intersex in freshwater fish species. Despite these concerns, there is a paucity of information regarding the complex dynamics of contaminant occurrence and co-occurrence in surface water across both space and time. To address these concerns, we applied a Bayesian hierarchical joint-contaminant model to describe the occurrence and co-occurrence patterns of 28 contaminants and total estrogenicity across six river sites and over three years. We found that seasonal occurrence patterns varied by contaminant, with the highest occurrence probabilities during the spring and summer months. Additionally, we found that the proportion of agricultural landcover in the immediate catchment, as well as stream discharge, did not have a significant effect on the occurrence probabilities of most compounds. Four pesticides (atrazine, metolachlor, fipronil and simazine) co-occurred across sites after accounting for environmental covariates. These results provide baseline information on the contaminant occurrence patterns of several classes of compounds within the Chesapeake Bay Watershed. Understanding the spatiotemporal dynamics of contaminants in surface water is the first step in investigating the effects of contaminant exposure on fisheries and aquatic environments.

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Onsite wastewater disposal systems (OWDS) can introduce bacterial and chemical contaminants, via groundwater, into aquifers and adjacent waterways. We evaluated the concentration of fecal indicator bacteria (FIB) and antibiotic resistant bacteria (ARB) in the shallow groundwater of Eastern Long Island, New York, downgradient of OWDS using cultivation approaches and analysis of 16 S rRNA genes. While FIB and ARB were detected in 80% and 67% of groundwater samples, respectively, concentrations were low, suggesting that, at least at the time of sampling, groundwater was not a large-scale source of fecal bacterial contamination to adjacent embayments. ARB isolates did not include common fecal associated genera and the concentration of FIB and ARB did not correlate well with the concentration of pharmaceutical contaminants, suggesting that bacterial contaminants were poorly linked to OWDS discharge. Concentrations of FIB in the studied embayments were significantly greater in nearshore compared to mid-channel environments, suggesting that land-based sources are likely to be the major contributors of bacterial contamination.

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Magnesium-ion batteries are a promising energy storage technology because of their higher theoretical energy density and lower cost of raw materials. Among the major challenges has been the identification of cathode materials that demonstrate capacities and voltages similar to lithium-ion systems. Thiospinels represent an attractive choice for new Mg-ion cathode materials owing to their interconnected diffusion pathways and demonstrated high cation mobility in numerous systems. Reported magnesium thiospinels, however, contain redox inactive metals such as scandium or indium, or have low voltages, such as MgTi2S4. This article describes the direct synthesis and structural and electrochemical characterization of MgCr2S4, a new thiospinel containing the redox active metal chromium and discusses its physical properties and potential as a magnesium battery cathode. However, as chromium(III) is quite stable against oxidation in sulfides, removing magnesium from the material remains a significant challenge. Early attempts at both chemical and electrochemical demagnesiation are discussed.

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Discharges from pharmaceutical manufacturing facilities (PMFs) previously have been identified as important sources of pharmaceuticals to the environment. Yet few studies are available to establish the influence of PMFs on the pharmaceutical source contribution to wastewater treatment plants (WWTPs) and waterways at the national scale. Consequently, a national network of 13 WWTPs receiving PMF discharges, six WWTPs with no PMF input, and one WWTP that transitioned through a PMF closure were selected from across the United States to assess the influence of PMF inputs on pharmaceutical loading to WWTPs. Effluent samples were analyzed for 120 pharmaceuticals and pharmaceutical degradates. Of these, 33 pharmaceuticals had concentrations substantially higher in PMF-influenced effluent (maximum 555,000 ng/L) compared to effluent from control sites (maximum 175 ng/L). Concentrations in WWTP receiving PMF input are variable, as discharges from PMFs are episodic, indicating that production activities can vary substantially over relatively short (several months) periods and have the potential to rapidly transition to other pharmaceutical products. Results show that PMFs are an important, national-scale source of pharmaceuticals to the environment.

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Stabilization of electrode-electrolyte interfaces is required to increase the energy stored in battery electrodes. Introducing redox-inactive ions on the electrode surface minimizes deleterious side reactions without affecting the bulk properties. A synthetic challenge exists to grow such layers conformally at each primary particle, to fully passivate interfaces that are buried in the final electrode architecture. The development of methods of sequential colloidal growth of complex oxides and overlayers, enabled by surfactant interactions, would provide novel means to advance toward this goal. Here, nanocrystals composed of LiCoO2, a commercially relevant material for high energy devices, were grown with a shell enriched in Al3+, deposited conformally through a one-pot colloidal synthetic method. The effects of synthetic conditions on the composition of the Al-rich shell and the corresponding electrochemical performance were investigated. The modified nanocrystals showed enhanced electrochemical properties, while maintaining carrier transport.

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Coastal onsite wastewater disposal systems (OWDS) were inundated by Hurricane Sandy's storm tide. This study compares the shallow groundwater quality (nutrients, pharmaceuticals, and hormones) downgradient of OWDS before and after Hurricane Sandy, where available, and establishes a baseline for wastewater influence on groundwater in coastal communities inundated by Hurricane Sandy. Nutrients and contaminants of emerging concern (CECs) were detected in shallow groundwater downgradient of OWDS in two settings along the New Jersey and New York coastlines: 1) a single, centralized OWDS in a park; and 2) multiple OWDS (cesspools) in low-density residential and mixed-use/medium density residential areas. The most frequently detected pharmaceuticals were lidocaine (40%), carbamazepine (36%), and fexofenadine, bupropion, desvenlafaxine, meprobamate, and tramadol (24-32%). Increases in the number and total concentration of pharmaceuticals after Hurricane Sandy may reflect other factors (seasonality, usage) besides inundation, and demonstrate the importance of analyzing for a wide variety of CECs in regional studies.

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Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region.

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Changes in bed sediment chemistry of Hempstead Bay (HB) have been evaluated in the wake of Hurricane Sandy, which resulted in the release of billions of liters of poorly-treated sewage into tributaries and channels throughout the bay. Surficial grab samples (top 5cm) collected before and (or) after Hurricane Sandy from sixteen sites in HB were analyzed for 74 wastewater tracers and steroid hormones, and total organic carbon. Data from pre- and post-storm comparisons of the most frequently detected wastewater tracers and ratios of steroid hormone and of polycyclic aromatic hydrocarbon concentrations indicate an increased sewage signal near outfalls and downstream of where raw sewage was discharged. Median concentration of wastewater tracers decreased after the storm at sites further from outfalls. Overall, changes in sediment quality probably resulted from a combination of additional sewage inputs, sediment redistribution, and stormwater runoff in the days to weeks following Hurricane Sandy.

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Direct linkages between endocrine-disrupting compounds (EDCs) from municipal and industrial wastewaters and impacts on wild fish assemblages are rare. The levels of plasma vitellogenin (Vtg) and Vtg messenger ribonucleic acid (mRNA) in male fathead minnows (Pimephales promelas) exposed to wastewater effluents and dilutions of 17α-ethinylestradiol (EE2), estrogen activity, and fish assemblages in 10 receiving streams were assessed to improve understanding of important interrelations. Results from 4-d laboratory assays indicate that EE2, plasma Vtg concentration, and Vtg gene expression in fathead minnows, and 17ß-estradiol equivalents (E2Eq values) were highly related to each other (R(2) = 0.98-1.00). Concentrations of E2Eq in most effluents did not exceed 2.0 ng/L, which was possibly a short-term exposure threshold for Vtg gene expression in male fathead minnows. Plasma Vtg in fathead minnows only increased significantly (up to 1136 µg/mL) in 2 wastewater effluents. Fish assemblages were generally unaffected at 8 of 10 study sites, yet the density and biomass of 79% to 89% of species populations were reduced (63-68% were reduced significantly) in the downstream reach of 1 receiving stream. These results, and moderate to high E2Eq concentrations (up to 16.1 ng/L) observed in effluents during a companion study, suggest that estrogenic wastewaters can potentially affect individual fish, their populations, and entire fish communities in comparable systems across New York, USA.

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There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO2) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO2 are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WxV1-xO2 nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122̅) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO2 structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

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To be able to control the functions of engineered multicomponent nanomaterials, a detailed understanding of heterogeneous nucleation at the nanoscale is essential. Here, by using in situ synchrotron X-ray scattering, we show that in the heterogeneous nucleation and growth of Au on Pt or Pt-alloy seeds the heteroepitaxial growth of the Au shell exerts high stress (∼2 GPa) on the seed by forming a core/shell structure in the early stage of the reaction. The development of lattice strain and subsequent strain relaxation, which we show using atomic-resolution transmission electron microscopy to occur through the slip of {111} layers, induces morphological changes from a core/shell to a dumbbell structure, and governs the nucleation and growth kinetics. We also propose a thermodynamic model for the nucleation and growth of dumbbell metallic heteronanostructures.

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A newly designed, 100 mm2, silicon drift detector has been installed on an aberration-corrected scanning transmission electron microscope equipped with an ultra-high resolution pole piece, without requiring column modifications. With its unique, windowless design, the detector's active region is in close proximity to the sample, resulting in a dramatic increase in count rate, while demonstrating an increased sensitivity to low energy X-rays and a muted tilt dependence. Numerous examples of X-ray energy dispersive spectrometry are presented on relevant materials such as Al x Ga1-x N nanowires, perovskite oxides, and polycrystalline CdTe thin films, across both varying length scales and accelerating voltages.

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In this report, we demonstrate band gap tuning of the active region emission wavelength from 365 nm to 250 nm in light emitting diodes fashioned from catalyst-free III-nitride nanowires. Optical characteristics of the nanowire heterostructures and fabricated devices are studied via electroluminescence (EL) and photoluminescence spectroscopy over a wide range of active region compositions. It is observed that for typical nanowire plasma assisted molecular beam epitaxy growth conditions, tuning of emission to wavelengths shorter than 300 nm is hampered by the presence of an optically active defect level. We show that by increasing the AlGaN nanowire growth temperatures this defect emission can be suppressed. These findings are applied to growth of the active region of a nanowire light emitting diode, resulting in a polarization-induced nanowire light emitting diode with peak EL at 250 nm.

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BACKGROUND: Safe adjustment of insulin therapy requires review of both long-term and short-term glycaemic control, HbA1c and blood glucose monitoring (BGM), respectively. OBJECTIVE: To summarise the information that HbA1c and BGM provide about glycaemic control and to outline how to use these measures to guide insulin therapy. DISCUSSION: There are three components to the 24-hour blood glucose profile: 1. the flat baseline set by the fasting blood glucose 2. often a daytime increment in this baseline 3. the prandial blood glucose increase. Insulin therapy aims to sequentially control each component to achieve a desired level of glycaemic control (usually HbA1c <7%). Clinical use of the two glycaemic measures requires that BGM results are not highly variable (which complicates safe insulin adjustment) and that both BGM and HbA1c results are reliable. If these conditions are met and there is a discrepancy between the BGM profile and the average blood glucose expected from the measured HbA1c, there may be periods of undetected hyper- or hypoglycaemia over the 24-hour period, which require changes in insulin therapy.

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The breaking of orbital degeneracy on a transition metal cation and the resulting unequal electronic occupations of these orbitals provide a powerful lever over electron density and spin ordering in metal oxides. Here, we use ab initio calculations to show that reversibly modulating the orbital populations on Mn atoms can be achieved at ferroelectric/manganite interfaces by the presence of ferroelectric polarization on the nanoscale. The change in orbital occupation can be as large as 10%, greatly exceeding that of bulk manganites. This reversible orbital splitting is in large part controlled by the propagation of ferroelectric polar displacements into the interfacial region, a structural motif absent in the bulk and unique to the interface. We use epitaxial thin film growth and scanning transmission electron microscopy to verify this key interfacial polar distortion and discuss the potential of reversible control of orbital polarization via nanoscale ferroelectrics.

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To determine the prevalence of mycotoxins in streams, 116 water samples from 32 streams and three wastewater treatment plant effluents were collected in 2010 providing the broadest investigation on the spatial and temporal occurrence of mycotoxins in streams conducted in the United States to date. Out of the 33 target mycotoxins measured, nine were detected at least once during this study. The detections of mycotoxins were nearly ubiquitous during this study even though the basin size spanned four orders of magnitude. At least one mycotoxin was detected in 94% of the 116 samples collected. Deoxynivalenol was the most frequently detected mycotoxin (77%), followed by nivalenol (59%), beauvericin (43%), zearalenone (26%), ß-zearalenol (20%), 3-acetyl-deoxynivalenol (16%), α-zearalenol (10%), diacetoxyscirpenol (5%), and verrucarin A (1%). In addition, one or more of the three known estrogenic compounds (i.e. zearalenone, α-zearalenol, and ß-zearalenol) were detected in 43% of the samples, with maximum concentrations substantially higher than observed in previous research. While concentrations were generally low (i.e. < 50 ng/L) during this study, concentrations exceeding 1,000 ng/L were measured during spring snowmelt conditions in agricultural settings and in wastewater treatment plant effluent. Results of this study suggest that both diffuse (e.g. release from infected plants and manure applications from exposed livestock) and point (e.g. wastewater treatment plants and food processing plants) sources are important environmental pathways for mycotoxin transport to streams. The ecotoxicological impacts from the long-term, low-level exposures to mycotoxins alone or in combination with complex chemical mixtures are unknown.

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