Growth variation of white oak subjected to historic levels of fluctuating air pollution

Growth of white oak (Quercus alba L.) trees was examined, using tree-ring analysis, at three sites near a small, remote coal-fired power plant in central Pennsylvania, USA. Forests immediately adjacent to the power plant have been subjected to power plant emissions since the power plant initiated operation in 1954. However, localized, ground-level fumigations have been gradually reduced over the years due to a series of construction projects resulting in increased stack heights. Comparisons of growth were made among the white oaks growing at the three close-in sites, as well to the growth of white oak at three control sites located 10-50 km from the power plant, during periods of differing stack heights. White oak exhibited reduced growth at two of the close-in sites during the time period when historical ground-level air pollution exposures were assumed to be greatest due to low stack heights. White oak growth at the third close-in site was not substantially reduced during this time period. In 1976, taller stacks were implemented at the power plant to reduce local, ground-level concentrations of air pollutants. The recovery of tree growth at the two close-in affected sites, and increased synchronous growth responses from 1976-85 among all three close-in sites, indicates that implementation of taller stacks in 1976 reduced ground-level pollutant levels to such dosages that growth was not impaired at any site. Also, growth rates after 1976 were comparable to the growth rates of the white oaks growing on the control sites. A possible interacting factor was a severe drought that occurred in the mid-1960s in central Pennsylvania.     

THE ROLE OF USER FEES AND CONGESTION TOLLS IN THE MANAGEMENT OF INLAND WATERWAYS1

ABSTRACT In this paper, we discuss how user fees and congestion tolls can be used to improve the efficiency and equity with which the inland waterway system is managed. The advantages and disadvantages of various types of user fees (fuel taxes, segment tolls, and license fees) are presented. The rationale for the employment of congestion tolls on congested waterways is discussed. A segment toll that is equated to average variable cost is recommended for uncongested existing waterwyas. When existing waterways are congested, congestion tolls, in addition to the segment tolls, are recommended, A two-part tariff, consisting of segment tolls and an annual license fee, is recommended for “new” uncongested waterways. A three-part tariff, consisting of the first two parts plus congestion tolls, is recommended for “new” congested waterways.     

Impact of Coal Ash from Electric Power Production on Changes in Water Quality1

ABSTRACT: Since 1972 the use of coal in the U.S. has increased much more rapidly than predicted, with much of this increased use by electric power generating plants. Residue after combustion consists primarily of inorganic materials, with the majority of chemical elements concentrated in fly ash as is sulfate. The concentration of sulfate in this ash fraction most affects the chemical and physical state of other elements when fly ash comes in contact with water by lowering the pH. In a properly constructed and operated ash settling basin, however, major water quality parameters of effluent may be improved as compared to source water. It is necessary, however, to consider the solubility or deposition in sediment of potentially toxic chemical elements from fly ash as these may affect reuse of this water, or as they may impact other parts of the aquatic environment.     

Development and evaluation of a Macroinvertebrate Biotic Integrity Index (MBII) for regionally assessing Mid-Atlantic Highlands Streams

The Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the Mid-Atlantic Highlands region (MAHR) by the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP). Over 100 candidate metrics were evaluated for range, precision, responsiveness to various disturbances, relationship to catchment area, and redundancy. Seven metrics were selected, representing taxa richness (Ephemeroptera richness, Plecoptera richness, Trichoptera richness), assemblage composition (percent non-insect individuals, percent 5 dominant taxa), pollution tolerance [Macroinvertebrate Tolerance Index (MTI)], and one functional feeding group (collector-filterer richness). We scored metrics and summed them, then ranked the resulting index through use of independently evaluated reference stream reaches. Although sites were classified into lowland and upland ecoregional groups, we did not need to develop separate scoring criteria for each ecoregional group. We were able to use the same metrics for pool and riffle composite samples, but we had to score them differently. Using the EMAP probability design, we inferred the results, with known confidence bounds, to the 167,797 kilometers of wadeable streams in the Mid-Atlantic Highlands. We classified 17% of the target stream length in the MAHR as good, 57% as fair, and 26% as poor. Pool-dominated reaches were relatively rare in the MAHR, and the usefulness of the MBII was more difficult to assess in these reaches. The process used for developing the MBII is widely applicable and resulted in an index effective in evaluating region-wide conditions and distinguishing good and impaired reaches among both upland and lowland streams dominated by riffle habitat.     

Fuzzy assessment of land suitability for scientific research reserves

Evaluating the characteristics of a set of sites as potential scientific research reserves is an example of land suitability assessment. Suitability in this case is based upon multiple criteria, many of which can be linguistically imprecise and often incompatible. Fuzzy logic is a useful method for characterizing imprecise suitability criteria and for combining criteria into an overall suitability rating. The Ecosystem Management Decision Support software combined a fuzzy logic knowledge base we developed to represent the assessment problem with a GIS database providing site-specific data for the assessment. Assessment of sites as a potential natural reserve for the new University of California campus at Merced demonstrates the benefits of fuzzy suitability assessment. The study was conducted in three stages of successively smaller assessment regions with increasingly fine spatial resolution and specificity of criteria. Several sites were identified that best satisfy the suitability criteria for a reserve to represent vernal pool habitat.     

Environmental bioavailability of hydrophobic organochlorines in sediments—A review

A number of hydrophobic organochlorines, such as hexachlorobenzene and polychlorinated dibenzo‐p‐dioxins/dibenzofurans (PCDD/Fs), have been reported to be persistent and bioaccumulative; however, their availability to biota appear to be limited due to strong sorption to soil/sediment and sequestration with age. Studies to date have shown that the bioavailability of hydrophobic organic chemicals (HOCs) in sediments is highly variable, depending not only on a chemical's lipophicity (K_ow), but also molecular steric conformation and sediment characteristics. A subdomain of sediment organic carbon, so‐called black carbon (BC), which has much higher affinity to planar HOCs than amorphous organic carbon, has been found to be the predominant repository of many HOCs. The sediment/soil‐bound HOCs are composed of a rapid and reversible desorbing labile fraction and a slow‐desorbing, or resistant‐to‐desorbing, nonlabile fraction. The latter can account for up to 98 percent of the total. A number of chemical extraction methods have been under development to measure the actual bioavailable concentrations in soil/sediment and have shown some correlation to the results of bioaccumulation and/or biodegradation tests. To date, most of the published studies on this subject have focused on polynuclear aromatic hydrocarbons (PAHs). This review summarizes the governing processes and the testing methodologies relevant to the environmental bioavailability of hydrophobic organochlorines in soils and sediments. © 2004 Wiley Periodicals, Inc.     

Managing bioremediation of a creosote‐contaminated superfund site by optimizing moisture and temperature in a biopile

Soil moisture content and temperature in a contaminated soil biopile equipped with immobilized microbe bioreactors (IMBRs) were optimized during ex situ bioremediation at a creosote‐contaminated Superfund site. Efficiency of remediation during warm summer months without soil‐temperature and moisture optimization was compared with that of cold winter months when corrective measures were applied. Significant reduction (35 percent) in total polycyclic aromatic hydrocarbons (PAHs) was observed, compared to 3.97 percent without corrective measures (p < 0.05). Kinetic rates (KRs) for total PAH removal were significantly enhanced from 3.93 to 50.95 mg/kg/day. KRs for removal of high molecular mass four‐to‐six‐ring PAHs were also significantly enhanced from 70.29 mg/kg/day to 97.45 mg/kg/day ( p < 0.05). Bioremediation of two‐ and three‐ring PAHs increased significantly from 15 percent to 40 percent. Benzo[a]pyrene toxicity equivalent mass (BaP_equiv) was significantly reduced by 48 percent with KR of 0.47 mg/kg/day as compared to 22 percent with KR of 0.14 mg/kg/day (p < 0.05). Soil moisture content was enhanced from 15.7 percent to 41.4 percent. © 2007 Wiley Periodicals, Inc.     

A case study of urban heat islands in the Carolinas

Urbanization tends to aggravate the negative effects of climate. The objective of this research is to aid in the understanding of the spatial variation of urban heat islands within selected cities in North and South Carolina. This understanding will help guide efforts to cool cities in order to increase human comfort, conserve energy and resources, and reduce air pollution in both of these states.