Role of protein, amino acids, and enzyme activity on odor production from anaerobically digested and dewatered biosolids.

The main objective of this research was to test the hypothesis that bioavailable protein and, more specifically, the sulfur-containing amino acids within the protein, can be degraded by proteolytic enzymes to produce odor-causing compounds--mainly volatile sulfur compounds (VSCs)--during biosolids storage. To achieve these objectives, samples of digester effluent and cake solids were collected at 11 different wastewater treatment plants in North America, and the samples were analyzed for protein and amino acid content and general protein-degrading enzyme activity. At the same time, cake samples were stored using headspace bottles, the concentration of VSCs were measured using gas chromatography, and olfactometry measurements were made by a trained odor panel. The results showed that the bound cake protein content and methionine content was well-correlated with VSC production and the detection threshold measured by the odor panel.     

Multimedia emissions inventory of polychlorinated biphenyls for the U.S. Great Lakes states

Polychlorinated biphenyls (PCBs) were banned in the United States in 1979, and since then a significant decline in their release to the environment has been observed. This decline has now reached a plateau. Several new regulatory programs have been put in place to further reduce PCB emissions/releases. However, our ability to measure the effectiveness of these regulatory/voluntary programs and to support regional fate/transport and source/receptor modeling efforts depend on reliable emission information. In this study, we attempt to improve the emission inventory for PCBs by compiling and analyzing the multimedia total PCB emission/release data reported for the U.S Great Lakes states for each year from 1990 to 2000. Although Toxic Release Inventory (TRI), National Emissions Inventory (NEI), Great Lakes Regional Air Toxic Emissions Inventory (GLRATEI), and Integrated Atmospheric Deposition Network (IADN) data formed the basis of estimating air emissions, we used the TRI, National Response Center (NRC), and PCB transformer inventory data to estimate PCB releases to land. We used the Permit Compliance System and NRC data to obtain estimates of PCB discharges to water systems in the Great Lakes states. The Remedial Action Plans for each area of concern were the primary source for estimating PCB loads of dredged sediments. On the basis of the NEI, IADN, and GLRATEI data, the total air emissions within the decade were approximately 126 t. The regionwide discharges to water systems and releases to land in the form of landfills and accidental spills in 1990-2000 were estimated as approximately 170 and 3225 t, respectively. We estimated that approximately 1.3 million t of PCB-contaminated sediment were removed or targeted for removal in five lakes of the U.S. portion of the Great Lakes basin. We stress that these estimates were based on reported amounts and the unreported PCB releases/emissions could result in significantly higher estimates.     

Demolition of High-Rise Public Housing Increases Particulate Matter Air Pollution in Communities of High-Risk Asthmatics

Abstract

Public housing developments across the United States are being demolished, potentially increasing local concentrations of particulate matter (PM) in communities with high burdens of severe asthma. Little is known about the impact of demolition on local air quality. At three public housing developments in Chicago, IL, PM with an aerodynamic diameter <10 μm (PM₁₀) and <2.5 μm were measured before and during high-rise demolition. Additionally, size-selective sampling and real-time monitoring were concurrently performed upwind and downwind of one demolition site. The concentration of particulates attributable to demolition was estimated after accounting for background urban air pollution. Particle microscopy was performed on a small number of samples. Substantial increases of PM₁₀ occurred during demolition, with the magnitude of that increase varying based on sampler distance, wind direction, and averaging time. During structural demolition, local concentrations of PM₁₀ 42 m downwind of a demolition site increased 4- to 9-fold above upwind concentrations (6-hr averaging time). After adjusting for background PM₁₀, the presence of dusty conditions was associated with a 74% increase in PM₁₀ 100 m downwind of demolition sites (24-hr averaging times). During structural demolition, short-term peaks in real-time PM₁₀ (30-sec averaging time) occasionally exceeded 500 μg/m³. The median particle size downwind of a demolition site (17.3 μm) was significantly larger than background (3 μm). Specific activities are associated with real-time particulate measures. Microscopy did not identify asbestos or high concentrations of mold spores. In conclusion, individuals living near sites of public housing demolition are at risk for exposure to high particulate concentrations. This increase is characterized by relatively large particles and high short-term peaks in PM concentration.     

On how environmental stringency influences adoption of best management practices in agriculture

There are relatively few Federal environmental regulations that influence agricultural production in the US. However, many local and state environmental rules may influence the management practices on US farms as might interactions between urban population centers and agricultural producers. Detailed analysis of corn farms gives insight into these relationships and suggests that stringent environmental regulations could increase the likelihood of adoption of certain conservation practices, all else being constant, but that the interaction between urban populations has less of an effect on the adoption decisions.     

Hepatic effects of yttrium oxide nanoflowers: in vitro risk evaluation

Yttrium oxide nanoflowers were prepared by a hydrothermal technique, and X-ray diffraction and scanning electron microscopy were used to determine their structures. The cytotoxic and genotoxic potentials of aqueous dispersions of the nanoflowers to cultured primary rat hepatocytes were examined at concentrations up to 500 mg L^?1 for 72 h. Cell viability was determined by monitoring the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, release of lactate dehydrogenase, and uptake of neutral red. Genotoxicity was assessed by the liver micronucleus assay. Exposure to Y₂O₃ nanoflowers at concentrations lower than 100 mg L^?1 did not lead to any cytotoxicity or genotoxicity. At higher concentrations (200, 400, and 500 mg L^?1), cell viability decreased and induction of micronuclei increased (400 and 500 mg L^?1).