A Benefit‐Cost Analysis of Total Maximum Daily Load Implementation1

Abstract: Total Maximum Daily Load (TMDL) implementation generates benefits and costs from water quality improvements, which are rarely quantified. This analysis examines a TMDL written to address bacteria and aquatic‐life‐use impairments on Abrams and Opequon Creeks in Virginia. Benefits were estimated using a contingent valuation survey of local residents. Costs were based on the number and type of best management practices (BMPs) necessary to achieve TMDL pollution reduction goals. BMPs were quantified using watershed‐scale water quality simulation models (Generalized Watershed Loading Function and Hydrological Simulation Program‐FORTRAN). Based on our projections, the costs to achieve TMDL induced pollution reduction goals outweigh the estimated benefits. Benefit‐cost ratios ranged between 0.1 and 0.3.     

Moving dirt: soil,lead, and the dynamic spatial politics of urban gardening

Urban gardens are often heralded as places for building social, physical, and environmental health. Yet they are also sites of significant conflict based on competing political, economic, and ecological projects. These projects range from radical re-envisionings of liberatory urban spaces, reformist aesthetic and sanitary improvement programmes, to underwriting the production of the neo-liberal city. These projects are based on divergent visions of the garden ground itself, in particular, whether this is soil (the fertile and living source for growing food and social values) or dirt (an inert and even problematic substrate to be removed or built upon for development purposes). These are not fixed or mutually exclusive categories, but are unstable as soil/dirt moves in discursive and material ways over time and space. Contaminants such as lead in the soil contribute to this instability, reframing fertile soil as dangerous dirt. To understand this discursive and material movement of soil/dirt over time and space, a dynamic spatial politics framework is needed that encompasses three scalar concepts: location, duration, and interconnection. This paper applies this dynamic spatial politics framework to interpret the 30-year conflict over the fate of an urban garden in Sacramento, California, that began as a countercultural space and was eventually transformed into a manicured amenity for a gentrifying neighbourhood, and the role of soil lead contamination in this narrative.     

Dealing With Uncertainty When Assessing Fish Passage Through Culvert Road Crossings

Assessing the passage of aquatic organisms through culvert road crossings has become increasingly common in efforts to restore stream habitat. Several federal and state agencies and local stakeholders have adopted assessment approaches based on literature-derived criteria for culvert impassability. However, criteria differ and are typically specific to larger-bodied fishes. In an analysis to prioritize culverts for remediation to benefit imperiled, small-bodied fishes in the Upper Coosa River system in the southeastern United States, we assessed the sensitivity of prioritization to the use of differing but plausible criteria for culvert impassability. Using measurements at 256 road crossings, we assessed culvert impassability using four alternative criteria sets represented in Bayesian belief networks. Two criteria sets scored culverts as either passable or impassable based on alternative thresholds of culvert characteristics (outlet elevation, baseflow water velocity). Two additional criteria sets incorporated uncertainty concerning ability of small-bodied fishes to pass through culverts and estimated a probability of culvert impassability. To prioritize culverts for remediation, we combined estimated culvert impassability with culvert position in the stream network relative to other barriers to compute prospective gain in connected stream habitat for the target fish species. Although four culverts ranked highly for remediation regardless of which criteria were used to assess impassability, other culverts differed widely in priority depending on criteria. Our results emphasize the value of explicitly incorporating uncertainty into criteria underlying remediation decisions. Comparing outcomes among alternative, plausible criteria may also help to identify research most needed to narrow management uncertainty.     

Effect of the Pittsburgh Air Pollution Episode upon Pulmonary Function in School Children

Due to increasing atmospheric concentrations of participates, five of Allegheny County’s seven monitoring areas were placed on first stage air pollution alert by November 18,1975. The Liberty Borough area reached second stage alert, and then emergency stage the morning of November 19. An investigation was mounted to determine whether these emergency levels of par-ticulates had an effect upon the pulmonary function of school children sufficiently severe that it would require several days for pulmonary function to return to normal. Beginning November 20 in two schools and November 21 in four additional schools, the three-quarter second forced expiratory volume (FEV.75) and the forced vital capacity (FVC) of approximately 270 parochial school children in fourth, fifth, and sixth grades were tested daily through November 26. Two schools, approximately 80 children, were in control areas; the remaining children were exposed to high or very high levels of particulate air pollution with significant levels of sulfur oxides. If a severe effect of pollution on pulmonary function occurred, one would expect daily measurements to tend upward in children in the four schools in polluted areas and to remain more or less steady in the two control areas. Analyses of the data yielded no indications of such an effect of air pollution upon the lung function of the school children studied. Pulmonary function values declined very slightly in all six schools over the study period. Unexplained variability over a weekend was observed.     

EPA SITE Demonstration of the International Waste Technologies/Geo-Con In Situ Stabilization/Solidification Process

This paper presents an EPA evaluation of the first field demonstration of an in situ stabilization/solidification process for contaminated soil under the EPA Superfund Innovative Technology Evaluation (SITE) program. Demonstration of this process was a joint effort of two vendors: ? International Waste Technologies (IWT) of Wichita, Kansas, who provided the treatment process, specifically the proprietary additive called HWT-20, and

? Geo-Con, Inc., of Pittsburgh, Pennsylvania, who provided both engineering and hardware for the in situ soil treatment.

The field demonstration took place in April, 1988 at a site in Hialeah, Florida, contaminated mainly with polychlorinated biphenyls (PCBs). EPA tested the soil before and after treatment and the EPA evaluation of this process is based on results from this testing. A year later, in April 1989, EPA tested again the treated soil and results of that testing were compared to those of the demonstration. Results of the EPA evaluation of the IWT process, the Geo-Con performance, and treatment costs are discussed separately.     

Effects of doping amounts of potassium ferricyanide with titanium dioxide and calcination durations on visible-light degradation of pharmaceuticals

Acetaminophen (ACT) is one of the most frequently detected pharmaceuticals in aqueous environments, and treatment of ACT were generally carried out by photocatalytic degradations under high energy UV irradiation. In this study, potassium ferricyanide was utilized as a quadruple-elemental dopant in a TiO₂ photocatalyst in order to enhance its visible-light activity. Two critical parameters (amounts of dopants and durations of calcination) of the synthesis of the photocatalyst by a sol–gel method were systematically evaluated. Crystal structure of the doping TiO₂ was examined by X-ray diffraction while the effects of the two parameters on the photocatalytic activity were elucidated by various characterizations. Increasing the amount of dopant or the duration of calcination red-shifted the UV–vis DRS of the doped TiO₂. The estimated band gap energy of the doped TiO₂ decreased slightly as the amount of dopant increased, but it increased as the duration of calcination increased. The FT-IR yielded characteristic peaks that revealed the effects of the two parameters, whereas the SEM images revealed the morphological evolutions of each effect. The photocatalyst, synthesized at optimum conditions was able to remove 99.1 % acetaminophen with rate constant of 7.9 × 10⁻³ min⁻¹, which was 4.88 times greater than virgin TiO₂. In general, this study not only optimized synthetic conditions of the new visible-light active photocatalyst for ACT degradation but also presented characterizations conducted by SEM, XRD, UV–vis DRS, and FTIR to elucidate the relationship between modified structure and the photocatalytic activity.

Effects of doping amounts of K₃[Fe(CN)₆] and calcunation duration on visible light absorbance of TiO₂ photocatalysts

     

From wetland to farm and back again: phosphorus dynamics of a proposed restoration project

We studied the phosphorus dynamics in a former wetland, which had been converted to a celery farm, and now consists of two shallow, flooded ponds that are being proposed for aquatic habitat restoration. However, like many agricultural areas, this site is plagued by phosphorus legacy issues. Proposed restoration includes hydrologic reconnection of these ponds to its adjacent stream, which are now isolated from one another by an earthen berm, to create a wetland complex. One of the two flooded ponds was partially dredged, whereas the other one has remained undredged. Water column, sediment pore water, and sediment total phosphorus concentrations were significantly greater in the undredged pond compared to the dredged pond, but in both cases phosphorus levels in the water columns (mean TP 929 vs. 133 μg/L in undredged vs. dredged ponds, respectively) would exacerbate downstream water quality issues if hydrologic reconnection occurred without first addressing the phosphorus issue. Sediment isotherm and maximum sorption data indicated that the sediments are close to phosphorus saturation in the undredged pond; simulated dredging of the cores revealed that exposure of deeper sediment layers would increase sorption capacity. Pore water SRP concentrations increased with sediment depth and were significantly greater in the undredged vs. dredged pond at both the 1–4-cm depth (2249 vs. 112 μg/L) and 14–17-cm depth (5506 vs. 222 μg/L). This study provides a framework for other projects that need to balance the competing demands of habitat restoration vs. water quality when restoring wetlands that have been converted to agricultural production.

     

Bioaccumulation of butyltins and liver damage in the demersal fish Cathorops spixii (Siluriformes,Ariidae)

The toxicity of butyltin compounds (BTs), mainly tributyltin (TBT), has been reported in different organisms. However, such an analysis in fish after field exposure with reference to the related biomarkers has not been commonly observed in the literature. This study presents the uptake of BTs in the liver of a neotropical marine catfish Cathorops spixii in Paranagua Bay, an important estuarine system located in southern Brazil. Two different areas, close to and distant from the harbor, were used for chemical analysis evaluation of hepatotoxicity through genetic, enzymatic, and histopathological biomarkers. The presence of polycyclic aromatic hydrocarbons in bile was also considered as a biomarker. The results showed a significant relationship between TBT levels and the inhibition of biotransformation enzymes and high occurrence of melanomacrophages in fish collected close to the harbor site. These effects were linked to the absence of TBT metabolites in the liver. In the second site, the presence of DBT was associated with an increase in EROD and GST activity. The larger amount of DNA damage as well as the highest oxidative stress was noted in fish from the less TBT-polluted area, where DBT and bile PAHs occurred. These findings showed different impact levels due to or increased by the chronic exposure of biota to BTs.     

Assessment of a regulatory model's performance relative to large spatial heterogeneity in observed ozone in Houston,Texas

In Houston, some of the highest measured 8-hr ozone (O₃) peaks are characterized by sudden increases in observed concentrations of at least 40 ppb in 1 hr, or 60 ppb in 2 hr. Measurements show that these large hourly changes appear at only a few monitors and span a narrow geographic area, suggesting a spatially heterogeneous field of O₃ concentrations. This study assessed whether a regulatory air quality model (AQM) can simulate this observed behavior. The AQM did not reproduce the magnitude or location of some of the highest observed hourly O₃ changes, and it also failed to capture the limited spatial extent. On days with measured large hourly changes in O₃ concentrations, the AQM predicted high O₃ over large regions of Houston, resulting in overpredictions at several monitors. This analysis shows that the model can make high O₃, but on these days the predicted spatial field suggests that the model had a different cause. Some observed large hourly changes in O₃ concentrations have been linked to random releases of industrial volatile organic compounds (VOCs). In the AQM emission inventory, there are several emission events when an industrial point source increases VOC emissions in excess of 10,000 mol/hr. One instance increased predicted downwind O₃ concentrations up to 25 ppb. These results show that the modeling system is responsive to a large VOC release, but the timing and location of the release, and meteorological conditions, are critical requirements. Attainment of the O₃ standard requires the use of observational data and AQM predictions. If the large observed hourly changes are indicative of a separate cause of high O₃, then the model may not include that cause, which might result in regulators enacting control strategies that could be ineffective.

Implications To show the attainment of the O₃ standard, the U.S. Environmental Protection Agency (EPA) requires the use of observations and model predictions under the assumption that simulations are capable of reproducing observed phenomena. The regulatory model is unable to reproduce observed behavior measured in the observational database. If the large observed hourly changes were indicative of a separate cause of high O₃, then the model would not include that cause. Inaccurate model predictions may prompt air quality regulators to enact control strategies that are effective in the modeling system, but prove ineffective in the real world.     

Secondhand smoke exposure is associated with smoke-free laws but not urban/rural status

The objective was to determine secondhand smoke (SHS) exposure with and without smoke-free laws in urban and rural communities. The research hypothesis was that SHS exposure in public places could be improved by smoke-free law regardless of urban and rural status. Indoor air quality in hospitality venues was assessed in 53 communities (16 urban and 37 rural) before smoke-free laws; 12 communities passed smoke-free laws during the study period. Real-time measurements of particulate matter with 2.5 µm aerodynamic diameter or smaller (PM_2.5) were taken 657 times from 586 distinct venues; about 71 venues had both pre- and post-law measurements. Predictors of log-transformed PM_2.5 level were determined using multilevel modeling. With covariates of county-level percent minority population, percent with at least high school education, adult smoking rate, and venue-level smoker density, indoor air quality was associated with smoke-free policy status and venue type and their interaction. The geometric means for restaurants, bars, and other public places in communities without smoke-free policies were 22, 63, and 25 times higher than in those with smoke-free laws, respectively. Indoor air quality was not associated with urban status of venue, and none of the interactions involving urban status were significant. SHS exposure in public places did not differ by urban/rural status. Indoor air quality was associated with smoke-free law status and venue type.

Implications:?This study analyzed 657 measurements of indoor PM_2.5 level in 53 communities in Kentucky, USA. Although indoor air quality in public places was associated with smoke-free policy status and venue type, it did not differ by urban and rural status. The finding supports the idea that population in rural communities can be protected with smoke-free policy. Therefore, it is critical to implement smoke-free policy in rural communities as well as urban areas.