236 research outputs found

    Evaluation of growth and yield model performance against remeasured permanent plots

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    The assessment of water use and reuse through reported data: A US case study

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    Increasing demands for freshwater make it necessary to find innovative ways to extend the life of our water resources, and to manage them in a sustainable way. Indirect water reuse plays a role in meeting freshwater demands but there is limited documentation of it. There is a need to analyze its current status for water resources planning and conservation, and for understanding how it potentially impacts human health. However, the fact that data are archived in discrete uncoordinated databases by different state and federal entities, limits the capacity to complete holistic analysis of critical resources at large watershed scales. Humans alter the water cycle for food production, manufacturing, energy production, provision of potable water and recreation. Ecosystems services are affected at watershed scales but there are also global scale impacts from greenhouse gas emissions enabled by access to cooling, processing and irrigation water. To better document these issues and to demonstrate the utility of such an analysis, we studied the Wabash River Watershed located in the U.S. Midwest. Data for water extraction, use, discharge, and river flow were collected, curated and reorganized in order to characterize the water use and reuse within the basin. Indirect water reuse was estimated by comparing treated wastewater discharges with stream flows at selected points within the watershed. Results show that during the low flow months of July–October, wastewater discharges into the Wabash River basin contributed 82 to 121% of the stream flow, demonstrating that the level of water use and unplanned reuse is significant. These results suggest that intentional water reuse for consumptive purposes such as landscape or agricultural irrigation could have substantial ecological impacts by diminishing stream flow during vulnerable low flow periods

    Time series analysis of water use and indirect reusewithin a HUC-4 basin (Wabash) over a nine year period

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    Anthropogenic water use and reuse represent major components of the water cycle. In the context of climate change, water reuse and recycling are considered necessary components for an integrated water management approach. Unplanned, or de facto, indirect water reuse occurs in most of the U.S. river systems, however, there is little real-time documentation of it. Despite the fact that there are national and state agencies that systematically collect data on water withdrawals and wastewater discharges, their databases are organized and managed in a way that makes it challenging to use them for water resource management analysis. The ability to combine reported water data to perform large scale analysis about water use and reuse is severely limited. In this paper, we apply a simple but effective methodology to complete a time series watershed-scale analysis of water use and unplanned indirect reuse for the Wabash River Watershed. Results document the occurrence of indirect water reuse, ranging from 3% to 134%, in a water-rich area of the U.S. The time series analysis shows that reported data effectively describe the water use trends through nine years, from 2009 to 2017, clearly reflecting both anthropogenic and natural events in the watershed, such as the retirement of thermoelectric power plants, and the occurrence of an extreme drought in 2012. We demonstrate the feasibility and significance of using available water datasets to perform large scale water use analysis, describe limitations encountered in the process, and highlight areas for improvement in water data management

    PAH Analysis of Sediments from Pleasant Run Creek adjacent to a Former Manufactured Gas Plant

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    Polycyclic aromatic hydrocarbons (PAHs) are known to be toxic and some are even carcinogenic. A prime source of PAHs is coal tar. Coal tar can be found in soils and sediments near former manufactured gas plants (MGPs) or coking facilities. This study involves characterizing the chemical composition and concentrations of PAHs within stream sediments at a former MGP site by Pleasant Run Creek in Indianapolis, Indiana. To characterize the stream sediments, sediment cores were removed from various locations along the stream and sampled with depth. Sample collection was conducted in partnership with the environmental engineering firm, August Mack Environmental. Samples were taken at 2 feet intervals from the surface (0.5 ft.) to a depth of 8 to 12 feet. Since the study is ongoing, samples continue to be processed in the lab to analyze concentrations of 17 PAHs by gas chromatography-mass spectrometry (GC/MS). A comparison between measured concentrations and published risk-based criteria will be performed to determine if observed concentrations pose an environmental risk. The results are expected to indicate significant PAH weathering (i.e., variable composition) in the sediment, due to the water volume and velocity of Pleasant Run Creek being affected by storm events. The results of this project will be used by August Mack Environmental to evaluate remediation strategies

    Contaminant Release from Storm Water Culvert Rehabilitation Technologies: Understanding Implications to the Environment and Long-Term Material Integrity

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    Millions of miles of existing U.S. storm water culverts are critical for roadway safety but much of this infrastructure requires repair. State departments of transportation (DOT) are increasingly choosing to rehabilitate culverts with spray-on and cured-in-place pipe (CIPP) lining processes. These culvert lining practices involve the manufacture of a new plastic liner inside a damaged culvert. DOTs are selecting these outdoor plastic manufacturing methods partly to avoid open-trench excavation, which can cause traffic disruption and work zone traffic safety issues. This study was conducted to better understand current knowledge about culvert lining caused environmental contamination, final product quality, and recommend improved construction specifications, project oversight, and testing requirements to limit undesirable consequences. Literature reviews, a survey of construction specifications and special provisions for 32 transportation agencies, as well as field- and bench-scale testing for CIPP projects in California, New York, and Virginia, were completed. During this project, the safety of workers, transportation agency employees, and the general public at lining installation sites, was raised as a concern by state and federal agencies. Due to previously unreported hazards which were encountered at multiple CIPP field sites, the provision of worksite safety recommendations for DOTs was added to this study. Recommendations are provided for spray-on lining and CIPP lining culvert repair projects that can (1) limit environmental contamination, (2) improve worksite safety, and (3) aid DOTs in better understanding the quality of their new liners

    Analysis of fullerene-C 60 and kinetic measurements for its accumulation and depuration in Daphnia magna

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    A simple method for analyzing masses of water suspended fullerenes (nC 60 ) in Daphnia magna by extracting to toluene and measuring by ultraviolet-vis spectrophotometry was developed. This method was used to assess bioaccumulation and depuration rates by daphnia after nC 60 exposure in artificial freshwater. Accumulation was rapid during the first few hours, and based on accumulation modeling, 90% of the steady-state concentration was reached in 21 h. After exposure for 24 h to a 2 mg/L fullerene solution, the daphnia accumulated 4.5 ± 0.7 g/kg wet weight, or 0.45% of the organism wet mass. Daphnids exposed to 2 mg/L fullerenes for 24 h eliminated 46 and 74% of the accumulated fullerenes after depuration in clean water for 24 and 48 h, respectively. Transmission electron microscopy revealed that the majority of the fullerenes present in the gut of daphnids were large agglomerates. The significant fullerene uptake and relatively slow depuration suggest that D. magna may play a role as a carrier of fullerene from one trophic level to another. Additionally, D. magna may impact the fate of suspended fullerene particles in aquatic ecosystems by their ability to pack fullerene agglomerates into larger particles than were found in the exposure water, and then excrete agglomerates that are not stable in water, causing them to settle out of solution. This process decreases fullerene exposure to other aquatic organisms in the water column but may increase exposure to benthic organisms in the sediment. Environ. Toxicol. Chem. 2010;29:1072–1078. © 2010 SETACPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71370/1/124_ftp.pd

    Relevance of octanol–water distribution measurements to the potential ecological uptake of multi-walled carbon nanotubes

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    Many potential applications of carbon nanotubes (CNTs) require various physicochemical modifications prior to use, suggesting that nanotubes having varied properties may pose risks in ecosystems. A means for estimating bioaccumulation potentials of variously modified CNTs for incorporation in predictive fate models would be highly valuable. An approach commonly used for sparingly soluble organic contaminants, and previously suggested for use as well with carbonaceous nanomaterials, involves measurement of their octanol–water partitioning coefficient ( K OW ) values. To test the applicability of this approach, a methodology was developed to measure apparent octanol–water distribution behaviors for purified multi-walled carbon nanotubes and those acid treated. Substantial differences in apparent distribution coefficients between the two types of CNTs were observed, but these differences did not influence accumulation by either earthworms ( Eisenia foetida ) or oligochaetes ( Lumbriculus variegatus ), both of which showed minimal nanotube uptake for both types of nanotubes. The results suggest that traditional distribution behavior-based K OW approaches are likely not appropriate for predicting CNT bioaccumulation. Environ. Toxicol. Chem. 2010;29:1106–1112. © 2010 SETACPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71369/1/etc_149_sm_supplData.pd

    Design Build

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    The 2011 Design/Build Studio included 13 undergraduate architects, 2 graduate architects, 6 landscape architects, and 1 interior designer. Under the careful supervision and guidance of Bruce Bassler, this team worked to design and deliver a complete sleeping cabin to the Scenic Park campground in South Sioux City, Nebraska

    Issues in Assessing Environmental Exposures to Manufactured Nanomaterials

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    Manufactured nanomaterials (MNs) are commonly considered to be commercial products possessing at least one dimension in the size range of 10−9 m to 10−7 m. As particles in this size range represent the smaller fraction of colloidal particles characterized by dimensions of 10−9 m to 10−6 m, they differ from both molecular species and bulk particulate matter in the sense that they are unlikely to exhibit significant settling under normal gravitational conditions and they are also likely to exhibit significantly diminished diffusivities (when compared to truly dissolved species) in environmental media. As air/water, air/soil, and water/soil intermedium transport is governed by diffusive processes in the absence of significant gravitational and inertial impaction processes in environmental systems, models of MN environmental intermedium transport behavior will likely require an emphasis on kinetic approaches. This review focuses on the likely environmental fate and transport of MNs in atmospheric and aquatic systems. Should significant atmospheric MNs emission occur, previous observations suggest that MNs may likely exhibit an atmospheric residence time of ten to twenty days. Moreover, while atmospheric MN aggregates in a size range of 10−7 m to 10−6 m will likely be most mobile, they are least likely to deposit in the human respiratory system. An examination of various procedures including the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal particle suspension stability in water indicates that more sophisticated approaches may be necessary in order to develop aquatic exposure models of acceptable uncertainty. In addition, concepts such as Critical Coagulation Concentrations and Critical Zeta Potentials may prove to be quite useful in environmental aquatic exposure assessments

    Seasonal differences in trace metal concentrations in the major rivers of the hyper-arid southwestern Andes basins of Peru

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    The southern rivers of Peru originate in the Andes Mountains and flow in a southwestern direction to the Pacific Ocean through one of the most hyper-arid regions of the world. During each sub-equatorial summer from December to February, rains and snow melt in the Andes increase the streamflow in these rivers, even as they pass through the 100 km arid zone to the ocean. This study quantified seasonal dynamics of 34 trace metal elements (TM) and other constituent concentrations in four southern river basins of Peru (Chili-Quilca, Tambo, Camana-Majes-Colca, and Ocoña) during 2019–2020. Consistent with previous studies, we observed that: (1) the river water in the southern basins had relatively high concentrations of B, As, Fe, Al, Mn, P, Pb and Ni, with As the most ubiquitous toxic TM in all the basins, often detected at concentrations surpassing Peruvian and USEPA regulated concentrations; and (2) basins with the most to least toxic TM contamination were the Tambo > Chili-Quilca > Camana-Majes-Colca > Ocoña. Seasonal streamflow strongly influenced the concentrations of twenty TM, with 15 TM (Al, Au, Ba, Cd, Co, Cu, Fe, Gd, Mn, Ni, P, Pb, Ti, Yb and Zr) consistently higher in the wet season, and with As, B, Ge, Li, and Pd higher in the dry season. Our results improve the understanding of seasonal variability and vulnerability in western Andes superficial water sources, which are highly influenced by both local geogenic and anthropogenic conditions. A Spanish translation of this paper is available in the online Supplementary Material
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