Occurrence and ecological hazard assessment of selected veterinary medicines in livestock wastewater treatment plants

The occurrence of some veterinary medicines in the livestock wastewater plants (WWTPs) was investigated. This investigation represented the occurrence of veterinary medicines to treat in the livestock WWTPs or be discharged into the water system in Korea since the sampling sites were widely distributed across the nation and samples were collected from the 11 livestock WWTPs. Nine antibiotics, two analgesics, and two disinfectants occurred in the livestock wastewater plants (WWTPs). From 11 livestock WWTP influents, chlortetracycline, oxytetracycline, acetylsalicylic acid, and disinfectants frequently occurred with the high concentrations. Meanwhile, sulfamethoxazole, erythromycin-H₂O, and trimethoprim did not occur during sampling periods. The values for log Kow of each chemical showed a high correlation with the number of hydrogen bonding acceptors and were important parameters to estimate and understand the biodegradability and toxicity of a compound in the environment. The biodegradability of each compound was proportional to the hydrophilicity of each compound and the toxicity was proportional to the number of hydrogen bonding acceptors of each compound. The expected introductory concentration (EIC), predicted exposure concentration (PEC), and hazard quotient showed that the livestock WWTP effluents were hazardous to ecosystems.     

Effects of As levels on radial oxygen loss and As speciation in rice

Greenhouse experiment was conducted to examine effects of arsenic (As) on iron plaque formation, radial oxygen loss, As accumulation, and speciation in rice. Three genotypes were grown in soil with three different concentrations of As. The stress of As caused a slight increase of iron plaque formation (P?>?0.05) and a decrease in the rates of radial oxygen loss (ROL; P?<?0.01). The results of As speciation showed that the percentages of DMA increased from 19–28 % to 53–58 %, while the percentages of inorganic As decreased from 53–58 % to 36–42 % with the increasing soil As concentrations, indicating a strong environmental influence on As species in rice grain. The present study showed that elevated soil As may induce As toxicity towards rice plants, leading to the decrease of ROL; environmental factors could influence As methylation or As species transportation. Our study provided useful information on As tolerance and accumulation in rice which may contribute to reducing the health risk posed by As contamination in rice.     

1990 Government Agencies Directory

ABSTRACT

The kinetics of pentachlorophenol (PCP) ozonation in terms of the gaseous O₃ and dissolved PCP concentrations has been investigated. When the O₃ concentration in the gas phase was in the range of 10 to 40 g O₃/m³, the O₃ dissolved for a short time period was proportional to the gaseous O₃ concentration. In this range, the ozonation reaction was first order for each reactant and the overall reaction was second order. At 25 °C, in an aqueous solution, the reaction rate constant was estimated to be 10.048 L/mol-sec. The reaction rate was much greater than the mass-transfer rate, indicating that the reaction of O₃ and PCP was an interface reaction on the surface of gaseous O₃ bubbles. The final product of the PCP ozonation was oxalic acid, with the carbon yield of the reaction being 59.4%. The ozonation of PCP in the aqueous solution was not a radical reaction but a direct reaction between O₃ and PCP molecules under the conditions investigated in this study, since O₃ has a high selectivity toward PCP. The reaction rate increased with the reaction temperature up to 35 °C but decreased at temperatures greater than 35 °C due to the decreased solubility of O₃. The addition of H₂O₂ did not increase the reaction rate significantly.     

Nitrate Artifacts during PM25 Sampling in the South Coast Air Basin of California

ABSTRACT

In February 1993, the South Coast Air Basin (SCAB) was redesignated as a “serious” nonattainment area for PM10. To improve the understanding and characterization of fine particulate matter in the SCAB, the South Coast Air Quality Management District (SCAQMD) initiated a comprehensive PM₁₀ Technical Enhancement Program (PTEP). Using enhanced PTEP monitors (specially designed multichannel/multifilter samplers), a one-year fine particulate matter (PM) monitoring program was initiated in January 1995. As part of the special monitoring program, nitric acid, ammonia, and speciated PM₁₀ and PM_2.5 concentrations were measured at five locations in the SCAB (downtown Los Angeles, Anaheim, Diamond Bar, Fontana, and Rubidoux) and at one background station (San Nicolas Island). The PM2.5 data are the first spatially resolved speciated data collected in the SCAB on an annual basis. Within the SCAB, where nitrate is a major component of PM_2.5, nitrate losses have been documented. The spatial and temporal variations of the nitrate losses during PM_2.5 sampling and the uncertainties of the nitrate losses are discussed. Significant losses occur at a low mass range, between 10 and 50 ìg/m³. Significant gains occur at an even lower mass range of less than 30 ìg/m³. On an annual average basis, nitrate losses vary between 1.25 and 2.32 ìg/m³ and the SCAB-wide average value of nitrate loss is 1.8 ìg/m³ based on five PTEP stations in the SCAB. The maximum nitrate losses for each station vary from 6.4 ìg/m³ to 22.5 ìg/m ³. Theoretical prediction of the sampling efficiency of the nitrate during PM_2.5 sam - pling was compared with the PTEP data. In general, theoretical prediction was in good agreement with measured values.     

Correlation of PCDD/F Emissions with Operating Parameters of Municipal Solid Waste Incinerators

ABSTRACT

Municipal solid waste incinerator (MSWI) operators frequently have expressed the need for an indirect indication of the expected production of PCDD/F and associated abatement procedures through a possible correlation with other real-time data, through using marker pollutants (e.g., penta/hexachlorinated aromatics), or through other indications. Since real-time measurement of PCDD/F is impossible, a correlation of PCDD/F emissions with other operating parameters could help in achieving these goals. Literature data of large-scale MSWIs concerning these correlations are scarce and seldom conclusive. Extensive data of Flemish MSWIs are used to statistically assess possible correlations of PCDD/F and other operating parameters.

The effect of temperature in the electrostatic precipita-tor (ESP) is of major importance. When converting values measured between 180 and 270 °C to a reference temperature of, for example, 230 °C, PCDD/F concentrations achieve nearly constant values, stressing that the major correlating parameter is the temperature of the ESP. High temperatures that enhance de novo synthesis should be avoided.     

Characterization of PM25 and PM10 in the South Coast Air Basin of Southern California: Part 2—Temporal Variations

ABSTRACT

The South Coast Air Quality Management District (SCAQMD) conducted a 1-year special particulate monitoring study from January 1995 to February 1996. This monitoring data indicates that high PM₁₀ and PM_{2 5} concentrations were observed in the fall (October, November, and December), with November concentrations being the highest. During the rest of the year, PM_2.5 and PM₁₀ masses gradually increased from January to September. Monthly PM₁₀ mass varied from 20 to 120 |ig/m³, and monthly PM₂₅ mass varied from 13 to 63 |j.g/m³. The PM_2.5-to-PM₁₀ ratio varied daily and ranged between 22 and 96%. Two types of high-PM days were observed. The first type was observed under fall stagnation conditions, which lead to high secondary species concentrations. The second type was observed under high wind conditions, which lead to high primary coarse particles of crustal components. The highest 24-hr average PM₁₀ concentration (226.3 |ig/m³) was observed at the Fontana station, while the highest PM₂₅ concentration (129.3 |ig/m³) was observed at the Diamond Bar station.     

Preparation of Sulfurized Powdered Activated Carbon from Waste Tires Using an Innovative Compositive Impregnation Process

Abstract

The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na₂S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m²/g and the S content of 2.61% by mass were obtained at 900°C and at the S feed ratio of 2160 mg Na₂S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased.     

Prediction of the Vertical Profile of Ozone Based on Ground-Level Ozone Observations and Cloud Cover

Abstract

A number of statistical techniques have been used to develop models to predict high-elevation ozone (O₃) concentrations for each discrete hour of day as a function of elevation based on ground-level O₃ observations. The analyses evaluated the effect of exclusion/inclusion of cloud cover as a variable. It was found that a simple model, using the current maximum ground-level O₃ concentration and no effect of cloud cover provided a reasonable prediction of the vertical profile of O₃, based on data analyzed from O₃ sites located in North Carolina and Tennessee. The simple model provided an approach that estimates the concentration of O₃ as a function of elevation (up to 1800 m) based on the statistical results with a ±13.5 ppb prediction error, an R² of 0.56, and an index of agreement, d ₁, of 0.66. The inclusion of cloud cover resulted in a slight improvement in the model over the simple regression model. The developed models, which consist of two matrices of 24 equations (one for each hour of day for clear to partly cloudy conditions and one for cloudy conditions), can be used to estimate the vertical O₃ profile based on the inputs of the current day’s 1-hr maximum ground-level O₃ concentration and the level of cloud cover.     

Evaluation of Biopolymer-Modified Concrete Systems for Disposal of Cathode Ray Tube Glass

Abstract

Cathode ray tubes (CRTs) from computer monitors and television sets, which contain significantly high percentage of lead (Pb) by weight, represent an enormous and growing hazardous waste problem in the United States and worldwide. As a result, new technologies are needed to cope with current CRT waste stream and increased hazard and build new markets for its recycled components, developing commercially viable concrete composites, as well as minimizing CRT disposal problems. In this study, commercially available biopolymers, such as xan-than gum, guar gum, and chitosan, were used to encapsulate CRT glass waste, reducing the Pb leachability. The biopolymers utilized contain a number of useful functional groups, such as carboxyl (xanthan), hydroxyl (guar), and amino groups (chitosan), which play important roles in binding and stabilizing Pb onto concrete structures. The use of biopolymers in concrete systems can create a stable interpenetrating cross-linking composite that will last for many years. Results from these new composites show 30% higher compressive strength than standard concrete and a sharp decrease in lead leachability from several thousand milligrams per liter initially to an amount of three-tenths milligrams per liter or lower values (much lower than the U.S. Environment Protection Agency standard for hazardous waste of 5 mg/L by the toxicity characteristic leaching procedure test), and for some of the composites leachability is below even the standard for drinking water. This efficient and cost-effective CRT–biopolymer-concrete composite is a new class of biopolymer-modified material that can potentially perform a significant role in relieving the current CRT issue.     

A Modal Approach to Vehicular Emissions and Fuel Consumption Model Development

Abstract

This study reports on the analysis of emissions and fuel consumption from motor vehicles using a modal approach. The four standard driving modes are idling, accelerating, cruising, and decelerating. On‐road data were collected using instrumented test vehicles traveling many times through the urban areas of Hong Kong. A model was developed for estimating vehicular fuel consumption and emissions as a function of instantaneous speed and driving mode. Piecewise interpolation functions were proposed for each nonidling driving mode. Idling emission and fuel consumption rates were estimated as negative exponential functions of idling time. Preliminary modeling results showed good agreements for the test vehicles and indicated that the on‐road measurements are feasible for the development of modal emission and fuel consumption models.