Preliminary Evaluation of the Use of Phosphogypsum for Reef Substrate. Ii. A Study of the Effects of Phosphogypsum Exposure On Diversity and Biomass of Aquatic Organisms

The effects of cement consolidated phosphogypsum (PG) on marine organisms was investigated under natural conditions in four 1000 m² estuarine ponds. Two ponds were seeded with 160 kg of PG arranged in aggregations of blocks and two ponds received similar mass of sand/cement blocks. Meiofauna were sampled quarterly and PG did not affect total meiofauna or major taxa (nematodes and copepods) density. Abundant species of copepods either were slightly increased in ponds with PG or were inconsistently affected.

All ponds were drained after one year. Three species of macroinvertebrates and 15 species of fishes were collected. Diversity indices showed modest but inconsistent variation among ponds. Only Pond 1 (control) and Pond 4 (experimental) had similar species abundances and all ponds showed unique distributions of biomasses among species. Thus, no differences in community structure attributable to the presence of PG could be detected among benthic invertebrates, natant invertebrates, or fishes.     

Emergency Planning and Community Right-to-Know

The Emergency Planning and Community Right-to-Know law is an exciting new approach to environmental protection. It is based on the belief that the more information citizens have about environmental conditions in their communities, the better equipped they will be to insure their own protection from unacceptable risks to their health and safety. The law requires disclosure by industry of both the presence and release into the environment—including both accidental and “routine” releases—of hazardous substances. The information will be available not only to government regulators, but also to the people most directly affected—the residents of the communities where the substances are located.     

Preliminary Estimates of Performance and Cost of Mercury Control Technology Applications on Electric Utility Boilers

ABSTRACT

Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications.

Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Regulatory requirements and tools for environmental assessment of hazardous wastes: Understanding tribal and stakeholder concerns using Department of Energy sites

Many US governmental and Tribal Nation agencies, as well as state and local entities, deal with hazardous wastes within regulatory frameworks that require specific environmental assessments. In this paper we use Department of Energy (DOE) sites as examples to examine the relationship between regulatory requirements and environmental assessments for hazardous waste sites and give special attention to how assessment tools differ. We consider federal laws associated with environmental protection include the National Environmental Policy Act (NEPA), the Resource Conservation and Recovery Act (RCRA), the Comprehensive Environmental Response Compensation and Liability Act (CERCLA), as well as regulations promulgated by the Nuclear Regulatory Commission, Tribal Nations and state agencies. These regulatory regimes require different types of environmental assessments and remedial investigations, dose assessments and contaminant pathways. The DOE case studies illustrate the following points: 1) there is often understandable confusion about what regulatory requirements apply to the site resources, and what environmental assessments are required by each, 2) the messages sent on site safety issued by different regulatory agencies are sometimes contradictory or confusing (e.g. Oak Ridge Reservation), 3) the regulatory frameworks being used to examine the same question can be different, leading to different conclusions (e.g. Brookhaven National Laboratory), 4) computer models used in support of groundwater models or risk assessments are not necessarily successful in convincing Native Americans and others that there is no possibility of risk from contaminants (e.g. Amchitka Island), 5) when given the opportunity to choose between relying on a screening risk assessments or waiting for a full site-specific analysis of contaminants in biota, the screening risk assessment option is rarely selected (e.g. Amchitka, Hanford Site), and finally, 6) there needs to be agreement on whether there has been adequate characterization to support the risk assessment (e.g. Hanford). The assessments need to be transparent and to accommodate different opinions about the relationship between characterizations and risk assessments. This paper illustrates how many of the problems at DOE sites, and potentially at other sites in the U.S. and elsewhere, derive from a lack of either understanding of, or consensus about, the regulatory process, including the timing and types of required characterizations and data in support of site characterizations and risk assessments.     

Calculating Air Quality and Its Control

Air quality is shown as a function of averaging times of five minutes to one year for carbon monoxide, hydrocarbons, nitric oxide, nitrogen dioxide, nitrogen oxides, oxidant, and sulfur dioxide in Chicago, Cincinnati, Los Angeles, New Orleans, Philadelphia, San Francisco, and Washington, D. C. Concentrations are approximately lognormally distributed for all pollutants in all cities for all averaging times. Maximum concentration is inversely proportional to averaging time to an exponent. The exponent is a function of the standard geometric deviation. General air quality and control parameters are derived and shown for one example, nitrogen oxides in Washington, D. C. These values are compared to one air quality standard.     

Models for preserving species diversity with backup coverage

The problem of selecting land for preservation of species has been a rich and active area of research over the past two decades. Typically, reserve selection models have tried to maximize species diversity by preserving areas that contain the greatest number of species. However, several studies have shown that seldom do these species-rich areas contain the rarest species most in need of protection. Most reserve selection models seek to maximize diversity by choosing parcels so that all species are covered by or represented in at least one parcel. This approach would usually be expected to result in coverage by a single parcel for the rarest species, especially for those that do not coincide with more abundant species. It is precisely these rare species, however, that would be lost or whose survivability would be most challenged, if the single parcels in which they are represented became unavailable due to some unforeseen event. In this paper, we introduce to reserve selection models the concept of secondary, or backup, coverage of species. Briefly stated, a species is said to have backup representation in the system of reserves if it is covered by, or represented in, two or more parcels. Having backup coverage guarantees that every species is still covered in the event that a natural or man-made catastrophe makes a given parcel uninhabitable. The results show that backup coverage can be obtained at little additional cost (as expressed by the number of parcels selected). Bi-objective formulations that trade-off primary with backup coverage show that backup coverage can be guaranteed for larger numbers of species with little reduction in primary coverage.     

Sustained treatment: Implications for treatment timescales associated with source‐depletion technologies

Sustained treatment is an emerging concept used to describe enhancements in attenuation capacity after the conclusion of the active treatment period for a given source‐depletion technology. The term includes mechanisms that lead to contaminant transformation or destruction over extended periods of time, such as endogenous biomass decay, slow diffusion of remedial amendments from low‐permeability zones, and the formation of reactive mineral species. This “value‐added” treatment continues after the end of capital expenditures at a site, and it provides additional insight in determining if monitored natural attenuation is a viable long‐term option for a site. This article identifies several sustained treatment mechanisms, examines technology‐specific factors that contribute to sustained treatment, and explores the potential timescales of sustained treatment relative to active treatment. As demonstrated in post‐treatment site data obtained during a comprehensive source‐depletion technology performance survey, enhanced bioremediation is the most promising in promoting sustained treatment, and this beneficial effect can extend for several years due to factors such as slow biomass decay. There is little evidence that other commonly used technologies (thermal treatment, in situ chemical oxidation, surfactant‐enhanced remediation, or cosolvent flushing) result in any significant sustained treatment. An exception would be a cosolvent flushing project where large quantities of biodegradable cosolvent are left in the subsurface at the end of the project, which could result in sustained long‐term dechlorination activity. In the case of in situ chemical oxidation, factors that contribute to a higher incidence of concentration rebound mask any potential sustained treatment effects. © 2011 Wiley Periodicals, Inc.