Evaluation of Watering to Control Dust in High Winds

ABSTRACT

A field study was conducted to determine the effectiveness of watering in controlling PM₁₀ emissions under high wind conditions. The focus of the study was the pickup of soil by a belly scraper at a landfill. Four low-volume PM₁₀ samplers were positioned downwind of the storage pile (at two distances, 80 and 110 m, and two elevations, 1 and 3 m) and one was located upwind at 3 m elevation. Integrating nephelometers, which measure the particu-late light scattering coefficient, b_sp, were also set up at locations 80 and 110 m downwind of the storage pile. Wind speed and direction were measured on-site. Samples were collected for two periods, one with and one without water being applied. Watering was effective at reducing PM₁₀ emissions at wind speeds up to the maximum 18 m sec^-1 observed at the landfill soil pickup operation. Measurement of b_sp provided an indication of PM₁₀ concentrations with better time resolution than samplers, but not with sufficient resolution, under the instrumental conditions used, to correlate with wind gusts.     

Mercury Measurement and Its Control: What We Know,Have Learned,and Need to Further Investigate

ABSTRACT

Based on the available evidence of health effects, the U.S. Environmental Protection Agency (EPA) has been evaluating the need to regulate mercury releases to the environment. In response to the congressional mandates in The 1990 Clean Air Act Amendments (CAAA), the EPA has issued the Mercury Study Report and the Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units Report. In spite of the enormous effort represented by these reports, as well as the efforts of both the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), in conducting the field measurement programs that form the basis for these reports, a definitive answer on the need for mercury regulation has not been found. However, the EPA, as well as other regulatory agencies and health researchers, have suggested a “plausible link” between anthropogenic sources emitting mercury and the methylation, bioaccumulation in the food chain, and adverse health effects in humans and wildlife.

Policy-makers have recognized that regulations must be based on good science and that a number of issues still remain. These issues can generally be grouped into four main categories: emissions inventory, control technology, fate of releases, and health effects. This paper will discuss recent, ongoing, and planned studies to address the remaining issues regarding the presence of mercury in the environment, with an emphasis on those studies that are directly related to the DOE/Federal Energy Technology Center’s (FETC) programmatic effort.     

Lipid-soluble conjugates of hydroxylated polybrominated diphenyl ethers in blue mussels from the Baltic Sea

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) of proposed natural origin have been detected throughout the food web of the Baltic Sea. Some OH-PBDEs have been shown to disrupt oxidative phosphorylation and the thyroid hormone system in exposed organisms. This paper describes an investigation into the fate of OH-PBDEs in the Baltic Sea’s predominant specie, the blue mussel. The main focus was on the conjugation of OH-PBDEs with lipophilic moieties (e.g., fatty acids) and the potential role this transformation mechanism may have in heavily exposed mussels in nature. Analytical methods were developed to accurately determine the concentrations of these conjugates in blue mussels collected on different occasions during the summer in a coastal area of the Baltic proper. The measured concentrations of conjugated OH-PBDEs were compared to those of the unconjugated parent compounds, and it was found that in some cases, the levels of the conjugated derivatives can be equal or even higher than the levels of the unconjugated OH-PBDEs. This is, to our knowledge, the first study on lipid-soluble OH-PBDE conjugates, and the first study to investigate the occurrence of such conjugates of halogenated phenolic compounds in environmentally exposed mussels. The mussels were also found to contain hydrolysable water-soluble derivatives of OH-PBDEs (such as e.g., glucuronic acid and/or sulfate conjugates etc.). These were tentatively determined to be of lower concentration (by up to an order of magnitude) than that of the OH-PBDEs which were conjugated with lipophilic moieties.     

Transmissivity as a Primary Metric for LNAPL Recovery—Case Study Comparison of Short‐Term vs. Long‐Term Methods

This article presents a case study and comparative analysis of light nonaqueous phase liquid (LNAPL) transmissivity estimated using short‐ and long‐term test methods at an active petroleum refinery. LNAPL transmissivity (Tn) is a recognized direct indicator of LNAPL recoverability with increasing acceptance by regulatory agencies. Historical releases at a refinery resulted in widespread LNAPL accumulations across the site and, as such, a focused approach is being implemented to enhance recovery, shorten remedial timeframes, and prioritize areas for recovery. Groundwater pumping systems operate continuously to maintain hydraulic containment of impacts, along with 12 LNAPL recovery systems. Transmissivity has been established as a primary metric and management tool for LNAPL recovery at the refinery. In this case study, estimated transmissivity values from short‐term data (baildown testing) and long‐term data (LNAPL skimming operations) from the same locations are analyzed and compared. Overall results are presented with respect to variations in transmissivities between the short‐ and long‐term tests, significance of data collection and quality, and consideration factors affecting transmissivity including fluid properties, soil types, hydrogeology, saturation levels, tidal effects, migration rates, and receptor risks. Additionally, the application of transmissivity as a metric for monitoring progress toward LNAPL recovery endpoints as part of the LNAPL remediation program development is discussed. ©2015 Wiley Periodicals, Inc.     

Influence of fipronil compounds and rice-cultivation land-use intensity on macroinvertebrate communities in streams of southwestern Louisiana, USA

Laboratory tests of fipronil and its degradation products have revealed acute lethal toxicity at very low concentrations (LC50) of <0.5 microg/L to selected aquatic macroinvertebrates. In streams draining basins with intensive rice cultivation in southwestern Louisiana, USA, concentrations of fipronil compounds were an order of magnitude larger than the LC50. The abundance (rho=-0.64; p=0.015) and taxa richness (r2=0.515, p<0.005) of macroinvertebrate communities declined significantly with increases in concentrations of fipronil compounds and rice-cultivation land-use intensity. Macroinvertebrate community tolerance scores increased linearly (r2=0.442, p<0.005) with increases in the percentage of rice cultivation in the basins, indicating increasingly degraded stream conditions. Similarly, macroinvertebrate community-tolerance scores increased rapidly as fipronil concentrations approached about 1 microg/L. Pesticide toxicity index determinations indicated that aquatic macroinvertebrates respond to a gradient of fipronil compounds in water although stream size and habitat cannot be ruled out as contributing influences.     

Improving effectiveness of systematic conservation planning with density data

Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated with species density. We hypothesized that conservation networks designed using species density distributions more efficiently conserve populations of all species considered than networks designed using probability of occurrence models. To test this hypothesis, we used the Zonation conservation prioritization algorithm to evaluate conservation network designs based on probability of occurrence versus density models for 26 land bird species in the U.S. Pacific Northwest. We assessed the efficacy of each conservation network based on predicted species densities and predicted species diversity. High‐density model Zonation rankings protected more individuals per species when networks protected the highest priority 10‐40% of the landscape. Compared with density‐based models, the occurrence‐based models protected more individuals in the lowest 50% priority areas of the landscape. The 2 approaches conserved species diversity in similar ways: predicted diversity was higher in higher priority locations in both conservation networks. We conclude that both density and probability of occurrence models can be useful for setting conservation priorities but that density‐based models are best suited for identifying the highest priority areas. Developing methods to aggregate species count data from unrelated monitoring efforts and making these data widely available through ecoinformatics portals such as the Avian Knowledge Network will enable species count data to be more widely incorporated into systematic conservation planning efforts.     

Designing cost efficient buffer zone programs: An application of the FyrisSKZ tool in a Swedish catchment

Riparian buffer zones are the only measure which has been used extensively in Sweden to reduce phosphorus losses from agricultural land. This paper describes how the FyrisSKZ web tool can be used to evaluate allocation scenarios using data from the Svärta River, an agricultural catchment located in central Sweden. Three scenarios are evaluated: a baseline, a uniform 6-m-wide buffer zone in each sub-catchment, and an allocation of areas of buffer zones to sub-catchments based on the average cost of reduction. The total P reduction increases by 30 % in the second scenario compared to the baseline scenario, and the average reduction per hectare increases by 90 % while total costs of the program fall by 32 %. In the third scenario, the average cost per unit of reduction (€163 kg P^?1) is the lowest of the three scenarios (58 % lower than the baseline) and has the lowest total program costs.