THERMAL DISCHARGES AND PUBLIC POLICY DEVELOPMENT1

ABSTRACT The generation of electric energy in steam-electric power plants is accompanied by the discharge of large quantities of waste heat into the environment. In most cases, this heat is released into natural bodies of water at temperatures relatively close to ambient. In certain locations, such as the Chesapeake Bay, discharges of waste heat may triple in the next decade. It is expected that past practices of thermal discharge, if continued into the future, will result in significant damages to other legitimate users of the water resource, both present and future. This paper reviews the economic causes of these potential damages, and describes the role of public policy as one of removing such causes through regulation incentive or intervention. Possible public policies are reviewed, including prohibition, standards, various types of dollar incentives such as taxes and subsidies, marketable effluent permits, and direct government investment. The innovative power plant siting program recently adopted in Maryland is also discussed. It is concluded that no statements can be made regarding the comparative efficiency or effectiveness of the various policies at the present state of knowledge. It is recommended that policy-makers adopt mixed strategies, preserving as many options as possible for dealing with similar problems in the future.     

The effect of humic acids on the sequential extraction of metals in soils and sediments using ICP-AES and chemometric analysis

The effect of humic acids on the sequential extraction of metals from various soils and sediments has been studied. A new multi-element extraction method optimised via experimental design has been employed. The method uses centrifugation to pass the extractant solution, at varying pH, through the sediment sample. The sequential leaches were collected and analysed by ICP-AES. Chemometric data processing was utilised to identify the composition of the physico-chemical components in order to characterise the sample. A sediment sample collected from Carnon River (Cornwall, UK) and a reference material (NIST 2711 agricultural soil) were spiked with humic acids and the sequential extraction scheme was used to monitor the changes in metal distribution. The method has proved a quick and reliable way to evaluate different sediment samples, and has potential as a new tool for environmental geochemistry analysis.     

Dioxins and polychlorinated biphenyls (PCDD/Fs and PCBs) in food from farms close to foot and mouth disease animal pyres

To control the outbreak of foot and mouth disease, which occurred in the UK in early 2001, a large number of farm animals were slaughtered. Where it was not possible to render or landfill the carcasses, they were destroyed by burning on open pyres, with wood, coal and other materials. Uncontrolled combustion such as this is known to produce small quantities of dioxins and an investigation was made into whether, as a result of the burning, there was an elevation in the concentrations of these compounds in food produced in the areas close to the pyres. With few exceptions, concentrations of PCDD/Fs and PCBs were within the expected ranges as predicted by reference data. No accumulation over time was evident from a repeat milk sampling exercise. Where elevated concentrations of PCDD/Fs and PCBs were found in chickens and eggs, they were in samples not destined for the food chain. Elevated levels in some samples of milk from Dumfries and Galloway were not found in earlier or later samples and may have been found as a result of a temporary feeding regime. Elevated concentrations in lamb from Carmarthenshire were from very young animals which would not have entered the food chain. There was no evidence of any significant increase in dietary exposure to PCDD/Fs and PCBs as a result of the FMD pyres.     

N-Nitrosamine formation from chloramination of two common ionic liquids

Ionic liquids(ILs) are a class of solvents increasingly used as "green chemicals." Widespread applications of ILs have led to concerns about their accidental entry to the environment.ILs have been assessed for some environmental impacts;however,little has been done to characterize their potential impacts on drinking water if ILs accidentally enter surface water.IL cations are often aromatic or alkyl quaternary amines that resemble structures of previously confirmed N-nitrosamine(NA) precursors.Therefore,this study has evaluated two common ILs,1-ethyl-3-methylimidazolium bromide(EMIm Br) and 1-ethyl-1-methylpyrrolidinium bromide(EMPyr Br),for their NA formation potential.Each IL species was reacted with pre-formed monochloramine under various laboratory conditions.The reaction mixtures were extracted using liquid–liquid extraction and analyzed for NAs using high performance liquid chromatography tandem mass spectrometry.At low concentration of IL(250 μmol/L),the yields of NAs(NMEA or NPyr) increased with increasing doses of monochloramine from both IL species.The total NA yield was as high as 2.5 ± 0.3 ng/mg from EMIm Br,and as high as 8.6 ± 0.8 ng/mg from EMPyr Br.At high concentration of IL(5 mmol/L),the NA yield reached a maximum at 2.5 mmol/L NH_2Cl,and then decreased with subsequent increases in the reactant concentrations,demonstrating ILs' solvent effects.This study re-emphasizes the importance of preventing discharge of ILs to water bodies to prevent secondary impacts on drinking water.     

THE IMPACT OF RUNOFF GENERATION MECHANISMS ON THE LOCATION OF CRITICAL SOURCE AREAS1

ABSTRACT: Identifying phosphorus (P) source areas and transport pathways is a key step in decreasing P loading to natural water systems. This study compared the effects of two modeled runoff generation processes ‐ saturation excess and infiltration excess ‐ on total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations in 10 catchment streams of a Catskill mountain watershed in southeastern New York. The spatial distribution of runoff from forested land and agricultural land was generated for both runoff processes; results of both distributions were consistent with Soil Conservation Service‐Curve Number (SCS‐CN) theory. These spatial runoff distributions were then used to simulate stream concentrations of TP and SRP through a simple equation derived from an observed relation between P concentration and land use; empirical results indicate that TP and SRP concentrations increased with increasing percentage of agricultural land. Simulated TP and SRP stream concentrations predicted for the 10 catchments were strongly affected by the assumed runoff mechanism. The modeled TP and SRP concentrations produced by saturation excess distribution averaged 31 percent higher and 42 percent higher, respectively, than those produced by the infiltration excess distribution. Misrepresenting the primary runoff mechanism could not only produce erroneous concentrations, it could fail to correctly locate critical source areas for implementation of best management practices. Thus, identification of the primary runoff mechanism is critical in selection of appropriate models in the mitigation of nonpoint source pollution. Correct representation of runoff processes is also critical in the future development of biogeochemical transport models, especially those that address nutrient fluxes.     

STEP WISE,MULTIPLE OBJECTIVE CALIBRATION OF A HYDROLOGIC MODEL FOR A SNOWMELT DOMINATED BASIN1

ABSTRACT: The ability to apply a hydrologic model to large numbers of basins for forecasting purposes requires a quick and effective calibration strategy. This paper presents a step wise, multiple objective, automated procedure for hydrologic model calibration. This procedure includes the sequential calibration of a model's simulation of solar radiation (SR), potential evapotranspiration (PET), water balance, and daily runoff. The procedure uses the Shuffled Complex Evolution global search algorithm to calibrate the U.S. Geological Survey's Precipitation Runoff Modeling System in the Yampa River basin of Colorado. This process assures that intermediate states of the model (SR and PET on a monthly mean basis), as well as the water balance and components of the daily hydrograph are simulated consistently with measured values.     

Distribution and speciation of metals in annual rings of black willow

Information on the spatial distribution and speciation of metals in nonhyperaccumulator plants is lacking. This study used synchrotron X-ray fluorescence (SXRF) compositional imaging to investigate the spatial distribution of Ni, Mn, Cu, Zn, and Fe in annual rings of black willow (Salix nigra L.) collected from a metal-contaminated area, and used X-ray absorption spectroscopy (XAS) to investigate Ni and Mn speciation in regions of the annual rings with elevated Ni concentrations. Annual rings were recollected in early 2003 from an individual known to be enriched with Ni from previous studies. Compositional imaging showed Ni and associated co-contaminants conservatively located in an annual ring. When compared with a corresponding photomicrograph, SXRF compositional images showed that metals were sharply constrained by the boundaries of the annual ring, indicating a sudden onset and cessation of uptake, and a lack of post-growth mobility of the metals. There was a particularly strong correlation between Ni and Mn in the metal-enriched annual ring (r = 0.8822), which suggested similar transport and binding behavior of these elements. X-ray absorption spectroscopy showed Ni and Mn to be present in the 2+ oxidation state. X-ray absorption near edge structure spectroscopy (XANES) fingerprinting of localized, highly Ni-enriched regions within the lumen of willow xylem vessels found similarities with Ni-pectic acid complexes, Ni-histidine, and NiSO4.     

SERENDIPITY: CAPTURING A DESIGN LEVEL PRECIPITATION EVENT1

ABSTRACT: On February 23–24, 1998, a frontal system moved across the U.S. Department of Energy's 3,500 km² Nevada Test Site (NTS) and resulted in significant depths of precipitation at all recording gages on the NTS. A preliminary analysis suggested that this precipitation event was of the magnitude and duration for which many flood mitigation structures have been designed. Given the data and field observations available and the potential implications of the event on the methodologies used to size flood mitigation structures throughout the West, a detailed analysis of this event was undertaken. The goals of this study were to compare this event with the regulatory design precipitation event, compare the estimated peak flow rates from the rainfall/runoff model used to size the flood mitigation structures at a radioactive waste management site with the estimated peak flows from the precipitation event, and examine if modification of the standard source of the design depths of precipitation is warranted.     

Public-private partnerships: spreading the three Rs

The privatization of government services is a complex, long-term endeavor with significant contractual, financial, operational and political considerations. This article addresses the very different perspectives of government and business toward privatization and identifies areas for negotiation based on examples in the water, solid waste, housing, energy and telecommunications sectors. The article also addresses the fundamentals of privatization—risks, responsibilities and rewards—and the ways in which business and government assess and allocate (or spread) these elements. The article then stresses that each entity must move beyond these basic assessments to better appreciate the legitimate perspectives of their counterparts at the negotiating table. Only then may a critical blending of goals and expectations begin to emerge and form the foundation for a successful privatization programme.