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At least 541 records · Page 30Linked to original sources
PubMed2002

Tritium doses from chronic atmospheric releases: a new approach proposed for regulatory compliance.

Regulatory models for atmospheric releases of tritium approved by the Environmental Protection Agency (CAP88, AIRDOS-PC, and COMPLY) calculate doses only from tritiated water (HTO) taken into the body. They do not deal with dose from emissions of tritiated hydrogen gas (HT) and conversion of HT to HTO in the environment, nor do they address the dose from ingesting tritium incorporated into organic compounds. A simple model (NEWTRIT) is proposed that accounts for all pathways to dose from atmospheric releases of HT and HTO. The model is formulated in terms of the tritium-to-hydrogen ratio in each environmental compartment. With each transfer, a small reduction in the ratio is introduced to reflect the dilution that occurs in nature. Conversion of HT to HTO in the environment is modeled using the latest experimental data. Concentrations of organically bound tritium are calculated in foodstuffs based on amounts of hydrogen in proteins, fats, and carbohydrates. Concentrations in foodstuffs and doses calculated by NEWTRIT are consistent with the predictions of existing regulatory models. In addition, the HTO component of NEWTRIT is tested using public bioassay data and the HT component is tested using results from a model intercomparison study for a hypothetical HT release. Although tritium doses probably have not been underestimated by regulatory models that account only for HTO (due to the high degree of conservatism built into these models), the explicit treatment of HT and organically bound tritium proposed here will make the dose assessments more comprehensive, defensible, and scientifically acceptable. Because NEWTRIT includes all pathways to dose and predicts conservative doses, it is a suitable model to replace the tritium models currently used for compliance.

Air Pollutants, Radioactive↗
PubMed2000

Pesticide residues and acute risk assessment--the US EPA approach.

The US Environmental Protection Agency (EPA) assesses acute dietary exposure to pesticide residues using a tiered approach, proceeding from conservative to more refined assumptions as the risk management situation requires. Toxicity and food residue data used by EPA in assessing acute dietary risk are obtained from studies submitted by chemical companies in support of pesticide registration and tolerance setting. The primary source of food consumption data used by EPA in acute dietary risk assessments is the Continuing Survey of Food Intakes by Individuals (CSFII) 1989-1991.

Data Interpretation, Statistical↗
PubMed2006

A cancer risk assessment of inner-city teenagers living in New York City and Los Angeles.

BACKGROUND: The Toxics Exposure Assessment Columbia-Harvard (TEACH) project assessed exposures and cancer risks from urban air pollutants in a population of high school teenagers in New York City (NYC) and Los Angeles (LA). Forty-six high school students participated in NYC and 41 in LA, most in two seasons in 1999 and 2000, respectively. METHODS: Personal, indoor home, and outdoor home 48-hr samples of volatile organic compounds (VOCs), aldehydes, particulate matter with aerodynamic diameter < or = 2.5 microm, and particle-bound elements were collected. Individual cancer risks for 13 VOCs and 6 particle-bound elements were calculated from personal concentrations and published cancer unit risks. RESULTS: The median cumulative risk from personal VOC exposures for this sample of NYC high school students was 666 per million and was greater than the risks from ambient exposures by a factor of about 5. In the LA sample, median cancer risks from VOC personal exposures were 486 per million, about a factor of 4 greater than ambient exposure risks. The VOCs with the highest cancer risk included 1,4-dichlorobenzene, formaldehyde, chloroform, acetaldehyde, and benzene. Of these, benzene had the greatest contributions from outdoor sources. All others had high contributions from indoor sources. The cumulative risks from personal exposures to the elements were an order of magnitude lower than cancer risks from VOC exposures. CONCLUSIONS: Most VOCs had median upper-bound lifetime cancer risks that exceeded the U.S. Environmental Protection Agency (EPA) benchmark of 1 x 10-6 and were generally greater than U.S. EPA modeled estimates, more so for compounds with predominant indoor sources. Chromium, nickel, and arsenic had median personal cancer risks above the U.S. EPA benchmark with exposures largely from outdoors and other microenvironments. The U.S. EPA-modeled concentrations tended to overestimate personal cancer risks for beryllium and chromium but underestimate risks for nickel and arsenic.

Adolescent↗
PubMed2001

Microbial inhibitors for U.S. EPA drinking water methods for the determination of organic compounds.

Preservation of chemical analytes in drinking water samples is necessary to obtain accurate information concerning contaminant occurrence. Sample preservation to prevent biodegradation is important for most samples and analytes. With the unique demands of environmental methods, it is not always possible to kill all microorganisms without having undesirable effects. To find a suitable preservative, the sample, analysis, and preservation needs should be considered. During method development of U.S. Environmental Protection Agency (EPA) Methods 526 (for unstable semivolatile compounds) and 532 (for phenylurea pesticides), a number of studies were conducted to identify compatible microbial inhibitors. Copper sulfate was successfully used in Method 532 and is an excellent first-choice antimicrobial agent for many applications. Copper sulfate can catalyze hydrolysis reactions for some pesticides such as those analyzed in Method 526. Under these conditions, a nonmetal compound of antimicrobial activity must be considered. During the development of Method 526, a survey of alternate organic based antimicrobial compounds found that diazolidinyl urea worked well in the method. Several other candidate microbial inhibitors were identified that could have application to other environmental methods. A general approach to selecting antimicrobial compounds in future environmental methods in water matrixes is discussed.

Anti-Infective Agents, Local↗
PubMed2006

Laboratory and field evaluation of instrumentation for the semicontinuous determination of particulate nitrate (and other water-soluble particulate components).

Studies conducted at the U.S. Environmental Protection Agency facility in Research Triangle Park, NC, and at a field study in Southern California have demonstrated the capability for the semicontinuous determination of particulate nitrate (and other water-soluble ionic species). Two instruments, an R&P Series 8400N Ambient Particulate Nitrate Monitor (8400N) and an ion chromatography (IC)-based prototype monitor developed at Texas Tech University, were evaluated both in the laboratory using aqueous standards and simulated ambient aerosols and in the field during a 3-week July 1-21, 2003) joint ambient comparison study with Brigham Young University and the South Coast Air Quality Management District (SCAQMD). The field study was conducted at the SCAQMD Rubidoux field site near Riverside, CA. During initial (before the field study) laboratory studies, both instruments were responsive to changes in the simulated aerosol concentration. However, potential problems were discovered involving both instruments during the laboratory-based studies both before and after the Rubidoux study, and these problems are currently being addressed. During the 3-week field study period, 15-minute average particulate nitrate concentrations approaching 30 microg/m3 were observed. Because of malfunctioning IC components (concentrator columns) of the Texas Tech University prototype monitor, limited data were obtained from this instrument during the 3-week sampling period. Initial ambient comparisons show general agreement between the 8400N and IC-based prototype instrument for the semicontinuous determination of ambient particulate nitrate at lower nitrate concentrations (<15 microg/m3) and an underdetermination by the 8400N at higher concentrations (>15 microg/m3). A decreased molybdenum converter efficiency in the pulse analyzer of the 8400N discovered during postfield study laboratory evaluation may explain the negative bias observed at higher nitrate concentrations. Semicontinuous results obtained from U.S. Environmental Protection Agency-operated instruments were averaged and compared with integrated sampler results obtained by Brigham Young University and SCAQMD.

Aerosols↗
PubMed1991

Future directions and research needs.

In this paper, three perspectives for indoor air issues are considered: a) air inside of our homes and offices is a major component of our overall living environment and has potentially great impact on public health; b) there are important scientific questions raised specifically to indoor air that will require skills and expertise to develop and interpret research and data collection efforts; and c) from a risk assessor's point of view, the types and quality of scientific information is critical to the process of health risk assessment to risk managers to make the best decisions regarding environmental risks from indoor air. The primary focus of this presentation is to highlight suggested future directions and needs of the U.S. Environmental Protection Agency that formed the core of a report to Congress on assessment and control of indoor air pollution. The five major areas that constitute the current EPA indoor air research strategy are monitoring/building studies; health effects; source characterization/mitigation; health impact/risk assessment; and program management/technology transfer. Additionally, major trends and research needs are discussed, including greater emphasis on noncancer effects and multiple pollutants at low levels and the need for more sensitive measures for detecting adverse health effects to more effectively characterize chemically sensitive individuals and population subgroups.

Air Pollution, Indoor↗
PubMedDate not supplied

Collection and evaluation of existing data: an ecological risk assessment perspective.

All scientific disciplines rely to some degree upon existing data to design new studies, test hypotheses, and make decisions. Because existing data can take many forms, a framework for addressing the quality of these data must be general and comprehensive. By nature of this inclusiveness, quality categories for existing data are necessarily broad. Effective employment of existing data requires the development of specific acceptance criteria from broad data quality categories. A framework is presented for collecting and evaluating existing data with examples of Environmental Protection Agency projects employing a tiered data review. The systematic planning inherent in a tiered review is described and attendant data quality considerations are developed in the context of an ecological risk assessment; specifically, the process is illustrated by defining an ecologically protective concentration of a chemical in soil.

Cadmium↗
PubMedDate not supplied

Radon: implications for the health professional.

Radon is a colorless, odorless gas formed by radioactive decay of radium and uranium, which are naturally present in the earth's crust. When concentrated indoors, this invisible gas becomes a potential health hazard. The Environmental Protection Agency estimates that up to 20,000 lung cancer deaths annually can be attributed to prolonged radon exposure. Radon is an important health issue that should be understood by all health care professionals. This paper discusses some of the important issues regarding radon, such as the incidences of lung cancer believed to be attributable to radon, the high-risk areas in the United States, federal safety guidelines, and public apathy. These issues and their impact on the health care required by professionals, especially nurse practitioners, are discussed.

Environmental Exposure↗
PubMed2004

Concentrations of dioxin-like PCB congeners in unweathered Aroclors by HRGC/HRMS using EPA Method 1668A.

We have determined the congener compositions of nine commercial Aroclor products of polychlorinated biphenyls (PCBs) to the sub-part-per-million level using high-resolution gas chromatography combined with high-resolution mass spectrometry according to US Environmental Protection Agency (EPA) Method 1668A. These Aroclor composition data should allow improved characterization and risk assessment of PCB contamination at hazardous waste sites, particularly for dioxin-like PCB congeners. By combining the data on the concentrations of each dioxin-like congener with its World Health Organization toxicity equivalency factor, we have established dioxin toxic equivalent concentrations for each pure Aroclor product.

Aroclors↗
PubMedDate not supplied

Management of infectious waste by US hospitals.

In July 1987 and January 1988, forty-six percent (441/955) of randomly selected US hospitals responded to a questionnaire intended to identify their waste disposal practices. Survey responses were received from hospitals in 48 states. United States hospitals generated a median of 6.93 kg of hospital waste per patient per day and infectious waste made up 15% of the total hospital waste. Most hospitals (greater than 90%) considered blood, microbiology, "sharps," communicable disease isolation, pathology, autopsy, and contaminated animal carcass waste as infectious. Other sources of hospital waste that were commonly (greater than 80%) designated infectious were surgical, dialysis, and miscellaneous laboratory waste. The infectious waste was normally (80%) treated via incineration or steam sterilization before disposal, whereas noninfectious waste was discarded directly in a sanitary landfill. Eight-two percent of these US hospitals are discarding blood, microbiology, sharps, pathology, and contaminated animal carcass waste in accordance with the Centers for Disease Control's recommendations, while the compliance rate for the Environmental Protection Agency's recommendations (excluding optional waste) is 75%. No hospital could identify an infection problem (excluding needle-stick injuries) that was attributable to the disposal of infectious waste. While the management of infectious waste by US hospitals is generally consistent with the Centers for Disease Control's guidelines, many hospitals employ overly inclusive definitions of infectious waste.

Centers for Disease Control and Prevention, U.S.↗
PubMed1997

Risk characterization: A bridge to informed decision making.

Regulatory decisions should be made in the most expert and informed way since they are precipitated by real and perceived threats to human health, under the glare of public scrutiny. In 1994, the National Research Council (NRC) reported that the U.S. Environmental Protection Agency's (USEPA's) overall approach to assessing risks is fundamentally sound, but the Agency must more clearly establish the scientific and policy basis for risk estimates and better communicate the associated uncertainties. On March 21, 1995, USEPA issued a risk characterization policy and guidance. In this policy, an effective risk characterization must fully and clearly characterize risks and disclose the scientific analysis, uncertainties, assumptions, and science policy that underlie decisions throughout the risk assessment process. A number of regulatory reform bills which required risk characterization as part of all Federal risk assessments were introduced by the 104th Congress. The purpose of this workshop was to familiarize Society of Toxicology members with: (1) key elements to be considered in risk characterization and (2) new advances in risk characterization addressed by Federal and State agencies, industry, academia, NRC, and Presidential/Congressional Commission on Risk Assessment and Risk Management. Furthermore, the main objective was to engage the audience in discussing the proper role of science in risk assessment-risk management interface to make informed decisions in the face of scientific uncertainty.

Decision Making↗
PubMedDate not supplied

Effect of household preparation on levels of pesticide residues in produce.

In 1993, the National Academy of Sciences released a report on the effects of pesticides in the diets of infants and children, indicating that current tolerances do not take into account the eating habits and metabolism of young children. In response to that report, a study was undertaken to determine pesticide residues in raw agricultural commodities at levels below the tolerances established by the Environmental Protection Agency. The objective of the study was to determine whether normal household washing, peeling, and cooking procedures had any effect on pesticide residue levels. Low levels of pesticide residues were detected in 97 (40%) of the 243 samples analyzed. The number of samples containing detectable residues dropped to 47 (19%) after household preparation. Results indicate that residue levels in most commodities are substantially reduced after household preparation.

Carbamates↗
PubMed1993

Summary of the 1992 EPA/A&WMA International Symposium: measurement of toxic and related air pollutants.

A joint conference cosponsored for the seventh year by the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the U.S. Environmental Protection Agency (EPA) and the Air & Waste Management Association (A&WMA) was held in Durham, North Carolina, May 4-8, 1992. The technical program consisted of 200 presentations held in 23 technical sessions and covered recent advances in ambient and source measurement techniques for air pollutants. The symposium was attended by almost a thousand professionals from the United States and other countries, covered a wide range of measurement topics, and was supported by 90 exhibitors of instrumentation and consulting services. This overview highlights the technical presentations of the symposium.

Air Pollutants↗
PubMed2000

The use of environmental risk assessment methodologies for an indoor air quality investigation.

The authors of this paper chose several target compounds that have been found in average US homes, applied the current United States Environmental Protection Agency (USEPA) Superfund risk assessment methodologies to indoor air quality, and produced risk numbers for hazard quotients and predicted increases in incidence of cancer which would be unacceptable at US hazardous waste sites. The calculations were made for the average child and adult with USEPA default exposure values. Calculations were also made for a worst case scenario using maximum concentrations and exposure estimates defined by the USEPA as describing the reasonable exposure (RME). Significant cancer risks and non-cancer hazard quotients were predicted.

Adult↗
PubMedDate not supplied

Computer validation in toxicology: historical review for FDA and EPA good laboratory practice.

The application of computer validation principles to Good Laboratory Practice is a fairly recent phenomenon. As automated data collection systems have become more common in toxicology facilities, the U.S. Food and Drug Administration and the U.S. Environmental Protection Agency have begun to focus inspections in this area. This historical review documents the development of regulatory guidance on computer validation in toxicology over the past several decades. An overview of the components of a computer life cycle is presented, including the development of systems descriptions, validation plans, validation testing, system maintenance, SOPs, change control, security considerations, and system retirement. Examples are provided for implementation of computer validation principles on laboratory computer systems in a toxicology facility.

Clinical Laboratory Information Systems↗
PubMed2004

The perils and promise of modern risk assessment: the example of trichloroethylene.

This article summarizes some of the major scientific shortcomings identified by reviewers of the draft "Trichloroethylene Health Risk Assessment: Synthesis and Characterization" (TCE HRA) in the context of current US Environmental Protection Agency risk assessment guidance and the Data Quality Act guidelines. Our purpose is not to further criticize the draft HRA but to highlight specific areas for improvement and suggest specific ameliorative actions that we believe would improve the scientific credibility (quality) of the final document. This exercise is expected to be applicable beyond the specific case of TCE, because the draft HRA surely exemplifies many of the new challenges being posed to risk assessment in general by the ever-increasing sophistication of modern science.

Animals↗
PubMed2006

Prevalence and implementation of IAQ programs in U.S. schools.

In this study, we determined the extent to which U.S. schools are implementing indoor air quality (IAQ) programs. We administered a questionnaire on IAQ programs and practices to a representative sample of schools. Participants were asked to provide information on the use, administration, implementation, challenges, and benefits of the IAQ program in their school. We developed an IAQ Practice Index to determine the level of activity directed toward IAQ in schools. The index was computed based on responses to specific survey questions and was normalized to a range of 0 to 100. Each question was weighted qualitatively according to its contribution to strong IAQ management practices. Forty-two percent of schools in the United States have an IAQ management program, and there has been sustained growth from 1998 through 2002 in the number of schools that have such programs. Nearly half of those schools use the U.S. Environmental Protection Agency's IAQ Tools for Schools program. The IAQ Practice Index scores varied widely for schools with an IAQ management program, suggesting that having a program is not equivalent to implementing effective IAQ policies and procedures. Respondents indicated that their IAQ programs led to improved workplace satisfaction, fewer asthma attacks, fewer visits to the school nurse, and lower absenteeism. When actively supported by the school administration, an IAQ program appears to be a valuable factor in improving the learning environment for U.S. schoolchildren.

Air Pollution, Indoor↗
PubMedDate not supplied

Chemical characterization of sanding dust and methylene chloride usage in automotive refinishing: implications for occupational and environmental health.

Surface preparation activities conducted during automotive refinishing present several potential human health and environmental risks. This study examines the chemical composition of vehicle sanding dust and the prevalence of methylene chloride use as a basis for evaluating potential chemical exposures in the work environment, fugitive environmental releases, and take-home toxics. This article reports on the findings of (1) a statewide technology and work practices survey of 353 licensed auto body shops and (2) laboratory analyses of sanding dust representing more than 200 vehicles, 10 commercial body filler compounds, and work shirts worn during vehicle sanding while using nonventilated equipment. Survey data revealed that the majority of shops (78%) do not use ventilated sanding equipment, that most workers (55%) take their work clothes and shoes home at the end of the workday, and that 17% of the respondents used a methylene chloride-based paint stripper as an adjunct to mechanical sanding. Laboratory results showed that Pb, As, Cr, Mn, and Ni were present in the sanding dust at every facility tested. Lead concentrations in sanding dust were found to be highest at facilities that performed complete vehicle refinishing (range 770 to 7300 ppm) and at a collision repair shop that used a high-lead content body filler compound (1800 ppm). Hexavalent chromium also was found in two vocational high school paint dust samples at concentrations of 54 and 710 ppm. When total lead and chromium concentrations reached 7300 and 2300 ppm, respectively, facility sanding dust samples failed the U.S. Environmental Protection Agency's Toxicity Characteristic Leaching Procedure for hazardous waste. Metals found in the sanding dust also were present on the work shirts of technicians-ranging from 0.06 (Cd) to 81 (Mg) microg/inch2 of cloth-who sanded on paint without ventilated equipment. Results suggest that sanding dust and methylene chloride paint strippers used in vehicle resurfacing operations pose a potential hazard to human health and the environment.

Automobiles↗