Nitrate Concentrations in Springs Flowing into the Lower Flint River Basin,Georgia U.S.A.1

Allums, Stephanie E., Stephen P. Opsahl, Stephen W. Golladay, David W. Hicks, and L. Mike Conner, 2012. Nitrate Concentrations in Springs Flowing Into the Lower Flint River Basin, Georgia U.S.A. Journal of the American Water Resources Association (JAWRA) 48(3): 423-438. DOI: 10.1111/j.1752-1688.2011.00624.x Abstract: Analysis of long-term data from (2001-2009) in four springs that discharge from the Upper Floridan aquifer into the Flint River (southwestern Georgia, United States) indicate aquifer and surface-water susceptibility to nutrient loading. Nitrate-N concentrations ranged from 1.74 to 3.30 mg/l, and exceeded historical levels reported for the Upper Floridan aquifer (0.26-1.52 mg/l). Statistical analyses suggest increasing nitrate-N concentration in groundwater discharging at the springs (n = 146 over eight years) and that nitrate-N concentration is influenced by a dynamic interaction between depth to groundwater (an indicator of regional hydrologic conditions) and land use. A one-time synoptic survey of 10 springs (6 springs in addition to the 4 previously mentioned) using stable isotopes generated δ¹⁵N-NO₃⁻ values (4.8-8.4‰ for rural springs and 7.7-13.4‰ for developed/urban springs) suggesting mixed sources (i.e., fertilizer, animal waste, and soil organic nitrogen) of nitrate-N to rural springs and predominantly animal/human waste to urban springs. These analyses indicate a direct relation between nitrate-N loading since the 1940s and intensification of agricultural and urban land use. This study demonstrates the importance of evaluating long-term impacts of land use on water quality in groundwater springs and in determining how rapidly these changes occur.     

Effects of red‐headed pine sawfly,Neodiprion lecontei,nuclear polyhedrosis virus on rainbow trout,Salmo gairdneri,and Daphnia pulex

Abstract

The effects of a nuclear polyhedrosis virus (NPV) of the red‐headed pine sawfly, Neodiprion lecontei, on rainbow trout, Salmo gairdnevi, were investigated. The fish were exposed to this virus by intubation and topical application and no ill‐effects were observed. Similarly, no ill‐effects were detected in Daphnia pulex when the same NPV was added to their culture medium. The materials were lyophilized, NPV‐infected sawfly larvae (normally used for insect control), lyophilized, unin‐fected larvae and purified, polyhedral inclusion bodies. On the basis of these laboratory tests, this virus, when disseminated as a biocontrol agent, should present no hazard to rainbow trout or to the aquatic invertebrate Daphnia pulex, two species frequently used in toxicity tests of chemical pesticides.     

Biodegradation of Bloodmeal-Based Thermoplastics in Green-Waste Composting

Polymers that are compostable and manufactured from renewable resources have gained significant importance in recent years. The objective of this work was to assess the biodegradability of bloodmeal-based thermoplastics in a commercial green-waste composting situation. Materials plasticised with tri-ethylene–glycol lost about 45% of their original mass after 12 weeks composting while unplasticised samples lost 35%. Degradation appeared to have been in two phases; an initial loss of soluble, low molecular compounds in the mesophilic phase followed by degradation of high molecular compounds as the temperature exceeded about 40 °C in the thermophilic phase. It was found that as degradation proceeded materials became more soluble. In addition, plasticised and unplasticized samples contained about 60 wt% moisture after 4 weeks of composting conditioning at 50% relative humidity resulted in approximately 8–10 wt% moisture, unaffected by the extent of degradation. FTIR revealed that proteins underwent hydrolytic cleavage resulting in the formation of primary amines. A significant reduction in combustion temperature was observed, indicative of a reduction in covalent bonding, likely due to shorter chains lengths or less cross-linking.     

Open-path,closed-path,and reconstructed aerosol extinction at a rural site

The Handix Scientific open-path cavity ringdown spectrometer (OPCRDS) was deployed during summer 2016 in Great Smoky Mountains National Park (GRSM). Extinction coefficients from the relatively new OPCRDS and from a more well-established extinction instrument agreed to within 7%. Aerosol hygroscopic growth (f(RH)) was calculated from the ratio of ambient extinction measured by the OPCRDS to dry extinction measured by a closed-path extinction monitor (Aerodyne’s cavity-attenuated phase shift particulate matter extinction monitor [CAPS PMex]). Derived hygroscopicity (relative humidity [RH] < 95%) from this campaign agreed with data from 1995 at the same site and time of year, which is noteworthy given the decreasing trend for organics and sulfate in the eastern United States. However, maximum f(RH) values in 1995 were less than half as large as those recorded in 2016—possibly due to nephelometer truncation losses in 1995. Two hygroscopicity parameterizations were investigated using high-time-resolution OPCRDS+CAPS PMex data, and the κ_ext model was more accurate than the gamma model. Data from the two ambient optical instruments, the OPCRDS and the open-path nephelometer, generally agreed; however, significant discrepancies between ambient scattering and extinction were observed, apparently driven by a combination of hygroscopic growth effects, which tend to increase nephelometer truncation losses and decrease sensitivity to the wavelength difference between the two instruments as a function of particle size. There was not a statistically significant difference in the mean reconstructed extinction values obtained from the original and the revised IMPROVE (Interagency Monitoring of Protected Visual Environments) equations. On average, IMPROVE reconstructed extinction was ~25% lower than extinction measured by the OPCRDS, which suggests that the IMPROVE equations and 24-hr aerosol data are moderately successful in estimating current haze levels at GRSM. However, this conclusion is limited by the coarse temporal resolution and the low dynamic range of the IMPROVE reconstructed extinction.

Implications: Although light extinction, which is directly related to visibility, is not directly measured in U.S. National Parks, existing IMPROVE protocols can be used to accurately infer visibility for average humidity conditions, but during the large fraction of the year when humidity is above or below average, accuracy is reduced substantially. Furthermore, nephelometers, which are used to assess the accuracy of IMPROVE visibility estimates, may themselves be biased low when humidity is very high. Despite reductions in organic and sulfate particles since the 1990s, hygroscopicity, particles’ affinity for water, appears unchanged, although this conclusion is weakened by the previously mentioned nephelometer limitations.     

In situ remediation of soils contaminated with toxic metal ions using microwave energy

Following onto our work on the in situ remediation of soils contaminated with PAH's, PCB's and other polychlorinated organic compounds using microwave energy, we now report a preliminary investigation on the in situ remediation of soils contaminated with toxic metal ions: Cd(II), Mn(II), Th(IV), Cr(III) and mainly Cr(VI). The soil is partially vitrified in the process, and extraction with hot (70 degrees C) 35% nitric acid for 4.5 h leads to the recovery of very small amounts of the metals which had been spiked into the clean soil: Cd, Mn, and Cr(III) are completely immobilized (unextractable), Th is mostly unextractable, and Cr(VI) partially extractable at very high levels of spiking, but almost completely unextractable using the US EPA Toxicity Characteristic Leaching Procedure. This suggests that contaminated soils which are not going to be used for agricultural purposes can be remediated safely to preset depths without fear of the toxic metal ions leaching out for a long time.     

A national critical loads framework for atmospheric deposition effects assessment: III. Deposition characterization

Methods are discussed for describing patterns of current wet and dry deposition under various scenarios. It is proposed that total deposition data across an area of interest are the most relevant in the context of critical loads of acidic deposition, and that the total (i.e., wet plus dry) deposition will vary greatly with the location, the season, and the characteristics of individual subregions. Wet and dry deposition are proposed to differ in such fundamental ways that they must be considered separately. Both wet and dry deposition rates are controlled by the presence of the chemical species in question in the air (at altitudes of typically several kilometers in the case of wet deposition, and in air near the surface for dry). The great differences in the processes involved lead to the conclusion that it is better to measure wet and dry deposition separately and combine these quantifications to produce “total deposition” estimates than to attempt to derive total deposition directly. A number of options for making estimates of total deposition to be used in critical loads assessment scenarios are discussed for wet deposition (buckets and source receptor models) and for dry deposition (throughfall, micrometeorology, surrogate surfaces and collection vessels, inference from concentrations, dry-wet ratios, and source-receptor models). The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract #68-C8-0006 with ManTech Environmental Technology, Inc., and Interagency Agreement #1824-B014-A7 with the U.S. Department of Energy and at Oak Ridge National Laboratory managed by Martin Marietta Energy Systems, Inc., under Contract DE-AC05-84OR21400 with the US Department of Energy. Environmental Sciences Division Publication No. 3905. It has been subjected to the Agency’s peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.     

Characterization of monitor recycling in Seattle, Washington

With the rapid growth of electronic waste (e-waste), policies that aim to effectively manage this waste stream have been introduced globally in recent years. Seattle, Washington, has been on the forefront of introducing policies to divert e-waste from the landfills and maximize recycling. With the introduction of the Take-it-Back-Network, a solid recycling infrastructure has existed in the Greater Seattle region since 2003. In 2009, the E-Cycle Washington program took into effect and now allows recyclers to offer free recycling of certain e-waste to households and small entities. Although policies to divert e-waste from the landfill to reuse and recycling is effective, there is also a need to analyze the current regional recycling infrastructure’s capacity to handle changing equipment and material quantities. This study aims to characterize the Seattle regional e-waste management capacity, with a focus on retired monitors as an example of a changing e-waste technology. We investigated waste computer monitor recycling in the Greater Seattle region, which includes the counties of King, Pierce, Snohomish, and Kitsap. Interviews were conducted on 20 collectors, 1 handler, and 2 processors to collect information on their business models, computer monitor management processes, and collection/processing quantities. Using this information, we summarize the material flows of end-of-life (EOL) cathode ray tube (CRT) and liquid crystal display (LCD) monitors in the region, both from the qualitative and quantitative perspective.     

Some Factors that Affect the Deposition Rates of Sulfur Dioxide and Similar Gases on Vegetation

The deposition of sulfur dioxide on growing vegetation is affected by diverse environmental factors, many of which undergo large diurnal and spatial variations. The aerodynamic resistance to vertical transfer in the surface boundary layer can be formulated in terms of the friction velocity, height of observation, vertical heat flux, and surface roughness. Also important are the resistance in the air layer closest to the surface elements and, in dry vegetation, the average stomatal resistance of the plants. The latter variable is among the most difficult to estimate, but over many agricultural field crops like those in the midwestern U.S., a typical minimum value of average stomatal resistance to SO₂ transfer is about 0.7 s cm^-1, as is indicated by various experimental data. The deposition velocity can be estimated as the inverse of the sum of the resistances of the layers, necessarily down to where the concentrations are zero; in the surface boundary layer, any of the various resistances might be dominant. Above the surface layer, the micrometeorological relationships are known with less certainty, but reasonable approximations indicate that during unstable conditions the resistance to transfer is very small at heights of several tens of meters and during stable conditions the aerodynamic resistance is very large aloft.     

Improving mental health status and coping abilities for long‐term unemployed youth using cognitive‐behaviour therapy based training interventions

This paper reports on immediate and long‐term well‐being outcomes for a group of long‐term unemployed youth who attended specially devised training courses based on the cognitive‐behaviour therapy (CBT) model. The courses were aimed specifically at improving the mental health of participants, and providing them with coping skills to deal better with the negative consequences of prolonged unemployment. Results for participants were compared with a waiting‐list, control group. Outcomes investigated were well‐being (psychological distress, self‐esteem, positive and negative affect), and coping behaviours (social support, self care, recreation, and cognitive coping strategies). Behavioural plasticity effects were also examined by comparing outcomes for participants who had higher distress scores prior to the course with participants who reported lower scores at that time. Immediate benefits were identified for both mental health and coping behaviours, and many of these benefits persisted into the long term. Participants with higher levels of pre‐course psychological distress improved more than their low distressed counterparts, supporting the behavioural plasticity hypothesis. Copyright © 1999 John Wiley & Sons, Ltd.     

The effects of plant traits and phylogeny on soil-to-plant transfer of Tc

Assessments of the behaviour of ⁹⁹Tc in terrestrial environments necessitate predicting soil-to-plant transfer. An experiment with 116 plant taxa showed that ⁹⁹Tc transfer to plants was positively related to plant dry weight but negatively related to % dry matter and age at exposure. Activities of ⁹⁹Tc analysed by hierarchical ANOVA coded with an angiosperm phylogeny revealed significant effects, with 55% of the variance between species explained at the Ordinal level and above. Monocots had significantly lower transfer of ⁹⁹Tc than Eudicots, within which Caryophyllales > Solanales > Malvales > Brassicales > Asterales > Fabales. There was a significant phylogenetic signal in soil-to-plant transfer of ⁹⁹Tc. This phylogenetic signal is used to suggest that, for example, a nominal Tc Transfer Factor of 5 could be adjusted to 2.3 for Monocots and 5.3 for Eudicots.