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PubMedDate not supplied

Population-based exposure measurements in EPA region 5: a phase I field study in support of the National Human Exposure Assessment Survey.

The National Human Exposure Assessment Survey (NHEXAS) Phase I study is designed to be part of the total NHEXAS framework developed from a series of scientific discussions and workshops conducted by the U.S. Environmental Protection Agency (EPA) during 1992 and 1993. NHEXAS examines total human exposure and is structured to include: Phase I, scoping studies; Phase II, a full national exposure survey; and Phase III, a series of highly focused characterization modules. Our research program examines the scientific issues important to Phase II, including statistical sampling, methods evaluation, media concentration measurements, formulating quality assurance goals, and identification of important pathways leading to exposure. To determine the feasibility of NHEXAS in characterizing human exposure for a representative population, a hypothesis-driven design is used to answer important questions about human exposure to specific environmental contaminants. This paper describes: (1) hypotheses to be tested; (2) contaminants selected for study; (3) strategies for measuring exposure; (4) study area and population; (5) population sampling design; (6) media sampling and analysis procedures; and (7) data analysis. The contaminants of concern in this Phase I study include selected metals and volatile organic compounds. From these classes the first-tier contaminants to be measured are lead, arsenic, benzene, chloroform, perchloroethylene, and trichloroethylene. Contaminants selected for examination may potentially be found in many media (personal-nonoccupational, personal-occupational, indoor, and outdoor residential air; dust; potable water; food/beverages; soil; blood; hair; and urine) and exposures may occur by multiple routes (inhalation, ingestion, dermal). The central hypothesis of our field study is to discover whether individual and population exposures determined by modeled or extant data are/are not significantly different from those determined directly from multipathway and multimedia measurements. In addition, there are a series of subhypotheses ranging from pollutant-specific exposure measurement and body burden hypotheses to the optimization of exposure models. In keeping with the NHEXAS framework, a probability-based population sample for total exposure and the field study will be conducted in counties located throughout EPA Region 5 (Minnesota, Wisconsin, Illinois, Indiana, Ohio, and Michigan). Sampling units will be households and an individual residing within each household. Environmental, exposure, and biological media sample collection will be performed by this consortium. Analyses of the external media and biological media samples will be completed by this consortium or Federal laboratories of the Centers for Disease Control and Prevention (CDC), Food and Drug Administration (FDA), or EPA. The protocols and analytical techniques selected for use represent the best available for total exposure assessment at this time.

Data Interpretation, Statistical↗

PubMed1999

Quantification of polycyclic aromatic hydrocarbons in soil at McMurdo Station, Antarctica.

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that have attracted much attention over the past several years. The United States Environmental Protection Agency (USEPA) has identified numerous PAHs as known or probable human carcinogens. The quantity of PAHs in the environment has dramatically increased, with the majority emitted from fossil fuel combustion sources. Surface soil samples were collected at McMurdo Station, Antarctica (77 degrees 51S, 166 degrees 41E), during peak summer activity and analyzed for PAHs. PAHS were detected at several locations, with maximum concentrations for naphthalene, acenaphthene, acenaphthylene, and fluoranthene at 27,000, 17,800, 15,700 and 13,300 mg/kg, respectively. Results suggest anthropogenic activities may be contributing to increased levels of PAHs present in McMurdo soils.

Antarctic Regions↗

PubMed2006

Comments on article "Applying mode-of-action and pharmacokinetic considerations in contemporary cancer risk assessments: an example with trichloroethylene" by Clewell and Andersen.

In their 2004 article, Clewell and Andersen provide their perspective on the application of mode-of-action (MOA) and pharmacokinetic considerations in contemporary cancer risk assessment using trichloroethylene (TCE) as a case example. TCE is a complex chemical toxicologically, with multiple metabolites, multiple sites of observed toxicity, and multiple potential MOAs. As scientists who are responsible for revising the U.S. Environmental Protection Agency's draft risk assessment of TCE, we welcome input of the quality to which the Agency is held accountable. However, in our view, Clewell and Andersen do not present a sufficiently current, complete, accurate, and transparent review of the pertinent scientific literature. In particular, their article would need to incorporate substantial recently published scientific information, better support its conclusions about MOA and choice of linear or nonlinear dose-response extrapolation, and increase its transparency as to quantitative analyses in order to make a significant contribution to the scientific discussion of TCE health risks.

Animals↗

PubMed1996

Is ingested inorganic arsenic a "threshold" carcinogen?

Ingested inorganic arsenic (As) is known to be a human carcinogen. An intriguing question is whether there is a threshold for the carcinogenic effects of As, i.e., is there a level below which it does not induce the development of cancer(s)? This Roundtable will discuss the United States Environmental Protection Agency's As risk assessment using the Taiwan data from different viewpoints. It will also consider the hypothesis that there is a threshold for As and data for or against this hypothesis. For example, some scientists believe that epidemiological data cannot answer this question, while others feel that different study designs and larger sampling will provide adequate data. Reasons for each position are given. This Roundtable discussion demonstrates the controversy surrounding the use of the Taiwan data for risk assessment.

Arsenic Poisoning↗

PubMed1989

Summary of the 1989 EPA/A&WMA International symposium: measurement of toxic and related air pollutants.

A joint conference, for the fourth straight year cosponsored by the Air & Waste Management Association's TP-6, TP-7, and ITF-2 technical committees, and the Atmospheric Research and Exposure Assessment Laboratory of the U.S. Environmental Protection Agency, was held at Raleigh, North Carolina, May 2-5, 1989. The technical program consisted of 145 presentations, held in 14 separate technical sessions, on recent advances in the measurement and monitoring of toxic and related pollutants found in ambient and source atmospheres. Covering a wide range of measurement topics and superbly supported by 57 exhibitors of instrumentation and consulting services, the symposium was enthusiastically received by more than 700 attendees from the United States and other countries. This overview contains a selection of the highlights from the technical presentations. A synopsis of the keynote address to the symposium is also included.

Air Pollutants↗

PubMed2005

Use of ozone-depleting substances; removal of essential-use designations. Final rule.

The Food and Drug Administration (FDA) is amending its regulation on the use of ozone-depleting substances (ODSs) in self-pressurized containers to remove the essential-use designations for albuterol used in oral pressurized metered-dose inhalers (MDIs). Under the Clean Air Act, FDA, in consultation with the Environmental Protection Agency (EPA), is required to determine whether an FDA-regulated product that releases an ODS is an essential use of the ODS. Two albuterol MDIs that do not use an ODS have been marketed for more than 3 years. FDA has determined that the two non-ODS MDIs will be satisfactory alternatives to albuterol MDIs containing ODSs and is removing the essential-use designation for albuterol MDIs as of December 31, 2008. Albuterol MDIs containing an ODS cannot be marketed after this date.

Adrenergic beta-Agonists↗

PubMed1994

Development and impact of the Gene-Tox-Program, genetic activity profiles, and their computerized data bases.

This invited historical review traces the development and impact of two major data bases in the field of genetic toxicology. Discussed from a personal perspective are the Environmental Protection Agency (EPA) Gene-Tox Program and the EPA/International Agency for Research on Cancer Genetic Activity Profiles (GAPs) and their respective data bases. Whereas Gene-Tox was focused on the assessment of short-term tests and their role in predicting carcinogens and mutagens, GAPs and the GAP data base were designed specifically to aid in the evaluation of individual chemicals. Both data bases have been computerized. Gene-Tox is available on TOXNET and GAP is available in a personal computer format from the author. The Gene-Tox and GAP data bases appear to have had substantial impact, particularly on hazard identification activities in cancer risk assessment.

Carcinogenicity Tests↗

PubMed2001

Developing seasonal ammonia emission estimates with an inverse modeling technique.

Significant uncertainty exists in magnitude and variability of ammonia (NH3) emissions, which are needed for air quality modeling of aerosols and deposition of nitrogen compounds. Approximately 85% of NH3 emissions are estimated to come from agricultural nonpoint sources. We suspect a strong seasonal pattern in NH 3 emissions; however, current NH3 emission inventories lack intra-annual variability. Annually averaged NH 3 emissions could significantly affect model-predicted concentrations and wet and dry deposition of nitrogen-containing compounds. We apply a Kalman filter inverse modeling technique to deduce monthly NH3 emissions for the eastern U.S. Final products of this research will include monthly emissions estimates from each season. Results for January and June 1990 are currently available and are presented here. The U.S. Environmental Protection Agency (USEPA) Community Multiscale Air Quality (CMAQ) model and ammonium (NH4+) wet concentration data from the National Atmospheric Deposition Program (NADP) network are used. The inverse modeling technique estimates the emission adjustments that provide optimal modeled results with respect to wet NH4+ concentrations, observational data error, and emission uncertainty. Our results suggest that annual average NH 3 emissions estimates should be decreased by 64% for January 1990 and increased by 25% for June 1990. These results illustrate the strong differences that are anticipated for NH3 emissions.

Agriculture↗

PubMed2004

Development of freshwater water-quality criteria for perchlorate.

The anion perchlorate (ClO4-) is an oxidizing component commonly used in solid propellants for rockets and missiles; in explosives, flares, fireworks, chemical processes, and automobile air-bag inflators; and for other assorted uses. With recent advances in analytical detection capability, perchlorate has been found in a variety of ground and surface waters throughout the United States. Because perchlorate has been associated with thyroid problems in humans and may have similar effects on wildlife, it is desirable to develop a water-quality criterion to assist in identifying concentrations of perchlorate in water likely to pose an ecological health risk. In the present study, we compiled all available data regarding the effects of perchlorate to aquatic organisms, and we performed additional toxicity and bioconcentration tests as required by the U.S. Environmental Protection Agency (U.S. EPA) for the development of water-quality criteria for aquatic life. A criterion maximum concentration of 20 mg/L and a criterion continuous concentration of 9.3 mg/L were calculated based on the test results. Although these are not formal Clean Water Act Section 304(a) criteria, which must be published by the U.S. EPA, these criteria may be useful in the determination of remedial action levels for contaminated sites, for National Pollutant Discharge Elimination System permit limits, and other water-quality management practices.

Animals↗

PubMedDate not supplied

An innovative blood lead screening program for Indian children.

There is little information on the lead levels of Indian children nationally. In the late 1990s, members of the Chippewa and Cree tribes living on the Rocky Boy Reservation near Box Elder, Montana, were concerned about environmental pollution and how it might be affecting the health of their children. With financial assistance from the Environmental Protection Agency, the tribes designed and implemented an innovative lead screening program for young children. Because most children on the reservation participated in WIC and Head Start, those programs were used to identify and screen close to 100% of young children on the reservation. The average blood lead level for children ages 1-5 on the Rocky Boy reservation was 2.4 micrograms/dL, which is not significantly different from that of children of the same age nationally. The project showed that Indian families will participate readily in screening programs that may improve their children's health.

Age Factors↗

PubMed1990

Comparison of water quality criteria and health advisories for 2,4,6-trinitrotoluene.

The U.S. Environmental Protection Agency (USEPA) has recently recommended health advisories (HAs) for 2,4,6-trinitrotoluene (TNT). The purpose of this brief article is to present these values so that the reader can compare them with the water quality criteria that have been proposed in another article (M. G. Ryon and R. H. Ross, 1990, Regul. Toxicol. Pharmacol. 11, 104-113). In that article, a water quality criterion of 140 micrograms/liter for TNT in drinking water was proposed, and in the present article the methodology by which USEPA calculated a lifetime HA of 2 micrograms/liter is presented. The reasons why the water quality criterion and the HA differ are discussed.

Humans↗

PubMed1989

Critical assessment of motor activity as a screen for neurotoxicity.

Motor activity consists of a large number of motor behaviors not placed under stimulus control. The Environmental Protection Agency defines motor activity in terms of "activity counts," and has incorporated it in the guidelines for the assessment of neurotoxicity. While motor activity testing has some enticing operating characteristics, a dose-related change in activity counts can reflect an effect on the nervous system only in the absence of systemic toxicity. Furthermore, when a motor activity effect has been documented, ancillary data or further testing is needed to determine whether this effect is indeed adverse. In addition, the results of a motor activity test do not usually provide information about either the origin of the problem, or the follow-up tests that need to be conducted.

Animals↗

PubMed1992

An evaluation of the role of epidemiology in assessing current and future disinfection technologies for drinking water.

Six members of the International Society for Environmental Epidemiology provide a discussion of the presentations of the authors of six studies dealing with the potential chronic disease side effects of water disinfection. This symposium, which was jointly sponsored by the Society and the United States Environmental Protection Agency (EPA) also involved state epidemiologists and engineers from state drinking water programs. This article summarizes the results of the studies and the comments about them. There was a general consensus that the recent EPA sponsored studies of cancer endpoints have strengthened the evidence linking bladder cancer with long term exposure to chlorinated drinking water. The evidence for links with colon cancer is not convincing and that for serum lipid changes is quite weak. Any risks, if real, are low when compared to the risk of infection from not disinfecting water. This is particularly true for small water systems where chlorination may be the only practical option.

Chloramines↗

PubMed2006

Comparison of techniques for the detection of helminth ova in drinking water and wastewater.

Many countries use wastewater for irrigation. The World Health Organization established, as reuse guidelines, a maximum value of 1 helminth ovum/L for irrigation. Various techniques for enumerating helminth ova in water have been published. To determine the most adequate method for Mexico, four techniques were compared: the U.S. Environmental Protection Agency (U.S. EPA), membrane-filter, Leeds I, and Faust. Two types of water were used: drinking water and municipal wastewater effluent. Sensitivity, discrimination coefficients, precision, recovery efficiency, and cost were determined. In addition, several unseeded wastewater samples were analyzed. For drinking water, U.S. EPA and the membrane-filter techniques demonstrated comparable results; however, when wastewater was used, the membrane technique showed some deficiencies. Because the U.S. EPA technique may be used for samples with both high and low solids content, allows for the recovery of helminth ova with different specific gravities, and has the lowest total cost, it was selected as the best technique.

Agriculture↗

PubMedDate not supplied

Indoor radon: a case study in risk communication.

Two key questions have influenced the development and implementation of the Environmental Protection Agency (EPA) program to reduce the public health risks of indoor radon gas; the answers may also apply to other preventive health care programs. First, how can we best communicate risk? Risk communication research indicates that simple message, persuasion, and prescriptive guidance will best encourage citizens to protect themselves from voluntary risks (within the control of the individual), such as radon. However, scientists expect technical information, logical and unemotional appeals, and detailed explanations of uncertainty. An appropriate balance between the persuasive and the technical will encourage public action and assuage the scientific community. Second, what environmental health care problems should we focus on? Public concern with involuntary risks imposed by an external force, such as hazardous waste dumps, drive our environmental health agenda. Consequently, because government decision-makers respond to public perceptions and pressures, which they frequently support, the largest fraction of the government's resources and the most aggressive protection programs are typically reserved for environmental health problems that pose involuntary risks. The experience of the EPA's Radon Program suggests that major gains in public health protection could be achieved through communication that effectively persuades people to accept personal responsibility for preventing voluntary risks, such as radon, and a more informed dialogue between the scientific community and the public concerning national priorities for environmental health protection.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Indoor↗

PubMed1999

Particle size separation via soil washing to obtain volume reduction.

A pilot-plant study was performed using a soil washing pilot plant originally designed by the Environmental Protection Agency (EPA) to demonstrate scale-up and potential full-scale remediation. This pilot plant named VORCE (Volume Reduction/Chemical Extraction) was modified to meet the specific requirements for treatment of the Formerly Utilized Sites Remedial Action Program (FUSRAP) and a Department of Energy site soils. After a series of tests on clean soils to develop operating parameters and system performance, the machine was used to treat soils, one contaminated with Thorium-232 and the other with Cesium-137. All indicate that soil washing is very promising for volume reduction treatment. In addition, cost data was generated and is given herein.

Cesium Radioisotopes↗

PubMed2006

The case for integrating low dose, beneficial responses into US EPA risk assessments.

When conducting risk assessments, the US Environmental Protection Agency (EPA) does not currently consider the beneficial effects from exposure to concentrations of agents below the no observed adverse effect level (NOAEL). If such benefits were observed, and if the beneficial and toxicological mechanisms of action were identical, this would probably be represented as a 'j-shaped' hormetic dose-response curve. If such data are available, they should be considered when assigning uncertainty factors for safe exposure calculations. However, when such data are not readily available, as is likely the case when the mechanism of action of the benefit differs from that of toxicity, current US EPA methods appear adequate.

Dose-Response Relationship, Drug↗

PubMedDate not supplied

European Union bans atrazine, while the United States negotiates continued use.

Atrazine is a common agricultural herbicide with endocrine disruptor activity. There is evidence that it interferes with reproduction and development, and may cause cancer. Although the U.S. Environmental Protection Agency (EPA) approved its continued use in October 2003, that same month the European Union (EU) announced a ban of atrazine because of ubiquitous and unpreventable water contamination. The authors reviewed regulatory procedures and government documents, and report efforts by the manufacturer of atrazine, Syngenta, to influence the U.S. atrazine assessment, by submitting flawed scientific data as evidence of no harm, and by meeting repeatedly and privately with EPA to negotiate the government's regulatory approach. Many of the details of these negotiations continue to be withheld from the public, despite EPA regulations and federal open-government laws that require such decisions to be made in the open.

Atrazine↗