Daily, monthly, seasonal, and annual ammonia emissions from Southern High Plains cattle feedyards

Ammonia emitted from beef cattle feedyards adds excess reactive N to the environment, contributes to degraded air quality as a precursor to secondary particulate matter, and represents a significant loss of N from beef cattle feedyards. We used open path laser spectroscopy and an inverse dispersion model to quantify daily, monthly, seasonal, and annual NH emissions during 2 yr from two commercial cattle feedyards in the Panhandle High Plains of Texas. Annual patterns of NH fluxes correlated with air temperature, with the greatest fluxes (>100 kg ha d) during the summer and the lowest fluxes (<15 kg ha d) during the winter. Mean monthly per capita emission rate (PCER) of NH-N at one feedyard ranged from 31 g NH-N head d (January) to 207 g NH-N head d (October), when increased dietary crude protein from wet distillers grains elevated emissions. Ammonia N emissions at the other feedyard ranged from 36 g NH-N head d (January) to 121 g NH-N head d (September). Monthly fractional NH-N loss ranged from a low of 19 to 24% to a high of 80 to 85% of fed N at the two feedyards. Seasonal PCER at the two feedyards averaged 60 to 71 g NH-N head d during winter and 103 to 158 g NH-N head d during summer. Annually, PCER was 115 and 80 g NH-N head d at the two feedyards, which represented 59 and 52% of N fed to the cattle. Detailed studies are needed to determine the effect of management and environmental variables such as diet, temperature, precipitation, and manure water content on NH emissions.     

Does iodine gas released from seaweed contribute to dietary iodine intake?

Thyroid hormone levels sufficient for brain development and normal metabolism require a minimal supply of iodine, mainly dietary. Living near the sea may confer advantages for iodine intake. Iodine (I₂) gas released from seaweeds may, through respiration, supply a significant fraction of daily iodine requirements. Gaseous iodine released over seaweed beds was measured by a new gas chromatography–mass spectrometry (GC–MS)-based method and iodine intake assessed by measuring urinary iodine (UI) excretion. Urine samples were obtained from female schoolchildren living in coastal seaweed rich and low seaweed abundance and inland areas of Ireland. Median I₂ ranged 154–905 pg/L (daytime downwind), with higher values (~1,287 pg/L) on still nights, 1,145–3,132 pg/L (over seaweed). A rough estimate of daily gaseous iodine intake in coastal areas, based upon an arbitrary respiration of 10,000L, ranged from 1 to 20 μg/day. Despite this relatively low potential I₂ intake, UI in populations living near a seaweed hotspot were much higher than in lower abundance seaweed coastal or inland areas (158, 71 and 58 μg/L, respectively). Higher values >150 μg/L were observed in 45.6% of (seaweed rich), 3.6% (lower seaweed), 2.3% (inland)) supporting the hypothesis that iodine intake in coastal regions may be dependent on seaweed abundance rather than proximity to the sea. The findings do not exclude the possibility of a significant role for iodine inhalation in influencing iodine status. Despite lacking iodized salt, coastal communities in seaweed-rich areas can maintain an adequate iodine supply. This observation brings new meaning to the expression “Sea air is good for you!”     

日本对生物技术安全准则及其标识政策的更新(2001)

日本于2001年4月1日生效的一项新法规规定,从国外进口不在所列名单中的转基因产品被视为非法。日本政府开始对进口货物进行检测,以确保其中不含不在名单中的转基因产品,如果含有且在目前阶段可以被检测出来,则必须对其进行标识。日本政府已批准了37种通过生物技术生产出来的产品。     

Evaluation of Quicklime Incorporation in Bench-Scale and Full-Scale Lime Stabilized Biosolids Using a Flat Surface pH Electrode

Abstract

Uniform lime incorporation into sewage sludge is critical for biosolid lime stabilization processes. There is no class B biosolids regulation for lime incorporation. The slurry method is currently used to evaluate the pH of limed biosolids, but this method homogenizes the biosolids and potentially masks poor lime mixing. In this study, a flat-surface pH electrode was used in bench-scale and full-scale experiments to measure the pH of lime-stabilized biosolids without creating slurries. The standard deviation of 15 pH measurements at different locations in a biosolid sample was used to assess mixing quality. The bench-scale experimental study showed that well-mixed limed biosolids had consistently high pHs (~12) with low standard deviations (<0.5 pH units), whereas poorly mixed biosolids had areas with low pH (<10) and high standard deviations (>2 pH units). Poorly mixed biosolids exhibited rapid and marked pH reduction, as well as offensive odor generation, whereas well-mixed biosolids resisted pH reduction and offensive odor generation. The full-scale study aimed at improving lime incorporation and biosolids quality confirmed the use of a flat surface pH electrode to capture low pH regions in biosolids that were masked by the current slurry method.     

PFAS Experts Symposium: Statements on regulatory policy,chemistry and analytics,toxicology, transport/fate,and remediation for per‐ and polyfluoroalkyl substances (PFAS) contamination issues

Sixty leading members of the scientific, engineering, regulatory, and legal communities assembled for the PFAS Experts Symposium in Arlington, Virginia on May 20 and 21, 2019 to discuss issues related to per‐ and polyfluoroalkyl substances (PFAS) based on the quickly evolving developments of PFAS regulations, chemistry and analytics, transport and fate concepts, toxicology, and remediation technologies.  The Symposium created a venue for experts with various specialized skills to provide opinions and trade perspectives on existing and new approaches to PFAS assessment and remediation in light of lessons learned managing other contaminants encountered over the past four decades. The following summarizes several consensus points developed as an outcome of the Symposium:

• Regulatory and policy issues: The response by many states and the US Environmental Protection Agency (USEPA) to media exposure and public pressure related to PFAS contamination is to relatively quickly initiate programs to regulate PFAS sites. This includes the USEPA establishing relatively low lifetime health advisory levels for PFAS in drinking water and even more stringent guidance and standards in several states. In addition, if PFAS are designated as hazardous substances at the federal level, as proposed by several Congressional bills, there could be wide‐reaching effects including listing of new Superfund sites solely for PFAS, application of stringent state standards, additional characterization and remediation at existing sites, reopening of closed sites, and cost renegotiation among PRPs.
• Chemistry and analytics: PFAS analysis is confounded by the lack of regulatory‐approved methods for most PFAS in water and all PFAS in solid media and air, interference with current water‐based analytical methods if samples contain high levels of suspended solids, and sample collection and analytical interference due to the presence of PFAS in common consumer products, sampling equipment, and laboratory materials.
• Toxicology and risk: Uncertainties remain related to human health and ecological effects for most PFAS; however, regulatory standards and guidance are being established incorporating safety factors that result in part per trillion (ppt) cleanup objectives. Given the thousands of PFAS that may be present in the environment, a more appropriate paradigm may be to develop toxicity criteria for groups of PFAS rather than individual PFAS.
• Transport and fate: The recalcitrance of many perfluoroalkyl compounds and the capability of some fluorotelomers to transform into perfluoroalkyl compounds complicate conceptual site models at many PFAS sites, particularly those involving complex mixtures, such as firefighting foams. Research is warranted to better understand the physicochemical properties and corresponding transport and fate of most PFAS, of branched and linear isomers of the same compounds, and of the interactions of PFAS with other co‐contaminants such as nonaqueous phase liquids. Many PFAS exhibit complex transport mechanisms, particularly at the air/water interface, and it is uncertain whether traditional transport principles apply to the ppt levels important to PFAS projects. Existing analytical methods are sufficient when combined with the many advances in site characterization techniques to move rapidly forward at selected sites to develop and test process‐based conceptual site models.
• Existing remediation technologies and research: Current technologies largely focus on separation (sorption, ion exchange, or sequestration). Due to diversity in PFAS properties, effective treatment will likely require treatment trains. Monitored natural attenuation will not likely involve destructive reactions, but be driven by processes such as matrix diffusion, sorption, dispersion, and dilution.

The consensus message from the Symposium participants is that PFAS present far more complex challenges to the environmental community than prior contaminants. This is because, in contrast to chlorinated solvents, PFAS are severely complicated by their mobility, persistence, toxicological uncertainties, and technical obstacles to remediation—all under the backdrop of stringent regulatory and policy developments that vary by state and will be further driven by USEPA. Concern was expressed about the time, expense, and complexity required to remediate PFAS sites and whether the challenges of PFAS warrant alternative approaches to site cleanups, including the notion that adaptive management and technical impracticability waivers may be warranted at sites with expansive PFAS plumes. A paradigm shift towards receptor protection rather than broad scale groundwater/aquifer remediation may be appropriate.     

Sorption, mobility, and transformation of estrogenic hormones in natural soil

Potent estrogenic hormones are consistently detected in the environment at low concentration, yet these chemicals are strongly sorbed to soil and are labile. The objective of this research was to improve the understanding of the processes of sorption, mobility, and transformation for estrogens in natural soils, and their interaction. Equilibrium and kinetic batch sorption experiments, and a long-term column study were used to study the fate and transport of 17beta-estradiol and its primary metabolite, estrone, in natural soil. Kinetic and equilibrium batch experiments were done using radiolabeled 17beta-estradiol and estrone. At the concentrations used, it appeared that equilibrium sorption for both estrogens was achieved between 5 and 24 h, and that the equilibrium sorption isotherms were linear. The log K(oc) values for 17beta-estradiol (2.94) and estrone (2.99) were consistent with previously reported values. Additionally, it was found that there was rate-limited sorption for both 17beta-estradiol (0.178 h(-1)) and estrone (0.210 h(-1)). An approximately 42 h long, steady-flow, saturated column experiment was used to study the transport of radiolabeled 17beta-estradiol, which was applied in a 5.00 mg L(-1) solution pulse for 44 pore volumes. 17beta-estradiol and estrone were the predominant compounds detected in the effluent. The effluent breakthrough curves were asymmetric and the transport modeling indicated that sorption was rate-limited. Sorption rates and distributions of the estrogens were in agreement between column and batch experiments. This research can provide a better link between the laboratory results and observations in the natural environment.     

Heavy metals in wastewater: Modelling the hydroxide precipitation of copper(II) from wastewater using lime as the precipitant

The effect of effluent composition (Cl⁻, SO₄²⁻ or CO₃²⁻) on the efficiency of the hydroxide precipitation of Cu(II) modelling lime (CaO) as the precipitant has been predicted using the solubility domain approach and has been experimentally validated. Solubility domains were based on the phases that were found to be solubility-limiting for systems representing potential effluent chemical composition limits. The generated solubility domains generally encompassed the experimentally observed solubilities, thereby providing effluent treatment quality assurance ranges for the hydroxide precipitation process. The presence of gypsum (CaSO₄.2H₂O) and calcite (CaCO₃) as secondary precipitates had little effect on the observed residual Cu(II) solubilities, with Cu(II) mobility being governed by the least-soluble kinetically precipitated (rather than thermodynamically favoured) phase in the system under study.     

MATHEMATICAL GENERALIZATION OF STREAM TEMPERATURE IN CENTRAL NEW ENGLAND1

ABSTRACT: The empirical fit of an annual harmonic function to stream temperature measurements in central New England can be improved by considering a harmonic period of less than 365 days instead of 365 or 366 days. Generalized equations, developed using periodic temperature data from 27 streamflow stations, allow predictions of stream temperature at any site given (1) the mean basin altitude (E), in meters above mean sea level, and (2) station latitude (LAT), in degrees. Stream temperature t, in degrees Celsius, on day number d, in days starting with January 1, is estimated as: in which, M = 31.48 – 0.0025 (E) ? 0.4635 (LAT) with standard error of estimate of 0.62°C, and τ= 1228.88 – 21.01 (LAT) with standard error of estimate of 14.1 days.     

A DECISION MODEL TO PREDICT SEDIMENT YIELD FROM FOREST PRACTICES1

ABSTRACT: In order to choose among “best management practices,” forest managers need to predict sediment yield to perennial streams following various forest land operations. The “universal soil loss equation” (USLE) is not directly applicable to forest operations because of the heterogenous soil surface conditions left by harvesting, site preparation, and planting. A sediment hazard index is proposed, to be based on the amount of exposed mineral soil and its proximity to streams. The model offered includes rainfall erosivity, soil erodibility and average land slope, together with the index W. A paired watershed experiment in the central Georgia Piedmont was used to estimate parameters in the model. The experimental basin (80 acres) was clearcut, drum roller chopped twice, and planted by machine. The standard error of estimate of sediment yield was computed to be about 50/lbs/ac per sampling period (four months). Use of William's erogivity index (storm flow times peak flow) reduced the standard error to 33/lbs/ac.