Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Environmental Protection Agency”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed1992

EPA priorities for biologic markers research in environmental health.

Recent advances in molecular and cellular biology allow for measurement of biologic events or substances that may provide markers of exposure, effect, or susceptibility in humans. The application of these new and emerging techniques to environmental health offers the possibility of significantly reducing the uncertainties that traditionally hamper risk assessments. The U.S. Environmental Protection Agency (EPA) health research program emphasizes the validation of appropriate biologic markers and their application to high-priority Agency issues. The rationale for EPA's biomarker research program is presented, and future research directions are discussed. Exposure biomarkers will receive most of the research emphasis in the near term, particularly body burden indicators of exposure to high-priority chemicals, such as benzene, ozone, selected heavy metals, and organophosphate pesticides. Research on effects biomarkers will attempt to validate the relationship between the observed biological effects and adverse health consequences in humans, especially for cancer, pulmonary toxicity, immunotoxicity, and reproductive/developmental toxicity.

Animals↗
PubMed1997

Toxicity identification of poultry litter aqueous leachate.

Poultry litter is a mixture of excreta, feed, feathers, and bedding material. Poultry litter is useful as a fertilizer due to the presence of nitrogen, phosphorus, and potassium. Litter is commonly used for growing corn, soybeans, potatoes, tomatoes, leafy vegetables, and cover crops. The aqueous leachate of poultry litter has been shown to exhibit toxicity to a variety of indicator organisms. The objective of this research was to identify classes of toxicants in the litter aqueous leachate. The aqueous extract of poultry litter was subjected to toxicity identification tests approved by the United States Environmental Protection Agency that use Ceriodaphnia dubia as the test organism. Tests performed included pH adjustment, filtration, aeration, C18 solid-phase extraction, EDTA addition, sodium thiosulfate addition, and extraction through zeolite. Zeolite extraction, filtration at low pH, and aeration at low pH reduced overall toxicity by 68, 20, and 22%, respectively. The major sources of toxicity appear to be ammonia and anionic organic compounds. Toxicity was apparently not due to the presence of heavy metals or oxidants.

Ammonia↗
PubMed1996

A Monte Carlo procedure for the construction of complementary cumulative distribution functions for comparison with the EPA release limits for radioactive waste disposal.

A Monte Carlo procedure for the construction of complementary cumulative distribution functions (CCDFs) for comparison with the U.S. Environmental Protection Agency (EPA) release limits for radioactive waste disposal (40 CFR 191, Subpart B) is described and illustrated with results from a recent performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP). The Monte Carlo procedure produces CCDF estimates similar to those obtained with importance sampling in several recent PAs for the WIPP. The advantages of the Monte Carlo procedure over importance sampling include increased resolution in the calculation of probabilities for complex scenarios involving drilling intrusions and better use of the necessarily limited number of mechanistic calculations that underlie CCDF construction.

Monte Carlo Method↗
PubMed2005

Contemplating the assessment of great river ecosystems.

The science and practice of assessing the status and trends of ecological conditions in great rivers have not kept pace with perturbation wrought on these systems. Participants at a symposium sponsored by the U.S. Environmental Protection Agency (USEPA) and the Council of State Governments concluded that useful and efficient assessments of great river ecosystems require thoughtful alignment of sampling designs, spatial and temporal scales, indicators, management needs, and ecosystem characteristics. Site-specific physical, chemical, and biological data long accumulated by monitoring programs have value but fail to provide the integrated system-wide perspective required for adaptive management and the Clean Water Act. Use of existing data may be limited by methodological incompatibilities, access difficulties, and the exclusive applicability of data to specific habitats or sites. The transition from site-specific to system-wide assessments benefits from research being done by USEPA's Environmental Monitoring and Assessment Program (EMAP) and other programs that use probability surveys and biological indicators. Indicators of various taxa (in particular fish, algae, and benthic invertebrates) have been successfully developed for great rivers. However, optimizing the information these ecological indicators convey to managers and the public is the subject of ongoing research.

Conservation of Natural Resources↗
PubMedDate not supplied

Reference dose (RfD): the possible impact of hormesis.

A fictitious US Environmental Protection Agency Administrator in the year 2005 is confronted with making a risk management decision on a chemical that exhibits an unambiguous hormetic effect in an animal system. Dose-response curves for average humans and sensitive humans are derived from the animal data. The question is posed: What should the reference dose (RfD) be in this case? A series of outstanding scientific and policy questions are discussed that have a bearing on the answer. The concept of the 'regulatory dose (RgD)' is revived to address, if not resolve, the issue.

Adaptation, Physiological↗
PubMedDate not supplied

Enumeration of Cryptosporidium spp. in water with US EPA method 1622, USA.

The occurrence of Cryptosporidium parvum or other pathogenic Cryptosporidium species in water must be known in order to assess risk and determine the treatment needed to reduce Cryptosporidium oocysts to acceptable levels in finished drinking water. Because Cryptosporidium oocyst occurrence may be sparse, methods must concentrate a large volume of water and correctly identify oocysts in the concentrate. The U.S. Environmental Protection Agency Information Collection Rule (ICR) protozoan method gives low and variable recoveries of Cryptosporidium oocysts, making risk assessment difficult. Therefore, a method giving better oocyst recovery and more consistent results was needed. Method 1622 was developed with existing materials and procedures, and improvements were made in filtration, cleanup, and detection. Absolute porosity filters were used, with cleanup by immunomagnetic separation and detection by direct fluorescent antibody stain with 4',6-diamidino-2-phenylindole (DAPI) staining for additional cell structures. Both the level and consistency of oocyst recovery were improved compared to recovery with the ICR method.

Animals↗
PubMed1987

Application of the preliminary developmental toxicity screen for chemical hazard identification under the Toxic Substances Control Act.

The Office of Toxic Substances (OTS) within the U.S. Environmental Protection Agency (EPA) is authorized to carry forth the mandates of the Toxic Substances Control Act (TSCA). Included among the provisions of TSCA are the development of requirements for testing of "new" and "existing" chemicals that may present an unreasonable risk of injury to health or the environment. There are over 63,000 "existing" chemicals on the TSCA inventory, and EPA in recent years has been receiving an average of over 1,300 submissions for "new" chemicals a year. Since it is illogical and unrealistic to expect that all of these chemicals should be subjected to detailed testing for all potential adverse health and environmental effects, OTS views screening assays as highly useful tools to assign priorities to chemicals for further testing according to standard methodologies. The Chernoff/Kavlock assay (preliminary developmental toxicity screen) was specifically developed to address the need for a developmental toxicity assay to prioritize for further testing the large number of "new" and "existing" chemicals. OTS has been involved in seeking the development of data through the preliminary developmental toxicity screen for purposes of validating the screen and to obtain critical data necessary for evaluating chemicals. OTS believes that the screen has a role in the risk assessment process and has developed a testing protocol, which is included along with other OTS test guidelines; has provided internal guidance on when the screen may be recommended; and has discussed how the data may be applied in prioritizing chemicals for further study.

Animals↗
PubMed2006

Characterization of background concentrations of contaminants using a mixture of normal distributions.

We present a Bayesian approach for characterizing background contaminant concentration distributions using data from sites that may have been contaminated. Our method, focused on estimation, resolves several technical problems of the existing methods sanctioned by the U.S. Environmental Protection Agency (USEPA) (a hypothesis testing based method), resulting in a simple and quick procedure for estimating background contaminant concentrations. The proposed Bayesian method is applied to two data sets from a federal facility regulated under the Resource Conservation and Restoration Act. The results are compared to background distributions identified using existing methods recommended by the USEPA. The two data sets represent low and moderate levels of censorship in the data. Although an unbiased estimator is elusive, we show that the proposed Bayesian estimation method will have a smaller bias than the EPA recommended method.

Bayes Theorem↗
PubMed2004

Resolving conflict and building cooperation in the National Estuary program.

Since its beginning in 1987, researchers and policymakers have touted the US Environmental Protection Agency National Estuary program (NEP) as one of the leading examples of collaborative institutions designed to resolve conflict and build cooperation at the watershed level. Using the NEP as an example, I summarize the advantages and disadvantages of collaborative institutions. Using data gathered from focused surveys of policy elites in 22 estuaries, I estimate statistical models that show the NEP does a better job of resolving conflict and building project-level cooperation than similar estuaries without the NEP. I also describe the activities of the NEP mentioned by respondents as contributing to this outcome.

Conflict of Interest↗
PubMed2000

Air pollution. Evidence mounts that tiny particles can kill.

Four years ago, the U.S. Environmental Protection Agency (EPA) ignited a fire storm when it declared that tens of thousands of people were dying each year from breathing tiny particles of dust and soot--and issued tough new regulations to crack down on these pollutants. Industry groups and many scientists assailed the decision, arguing that the data underlying the new particulate matter standard were inconclusive at best, and industry took their case to court. Now, a long-awaited study, by a group widely perceived to be politically neutral, comes in solidly behind the earlier EPA decision and strongly implicates particles in excess deaths.

Air Pollutants↗
PubMed2001

Uncertainties in the reference dose for methylmercury.

This paper critically examines the National Academy of Sciences and the National Research Council report on the toxicological effects of methyl mercury and the recently published US Environmental Protection Agency Reference Dose (RfD) for Methylmercury. Particular scrutiny is placed on the choice of the critical study and the underlining assumptions utilized in the selection of specific uncertainty factors (UFs) and the rationale for using a less-than-default factor of 10. The UFs that were utilized or considered by other agencies and organizations are also critically examined, explained and compared to one another. Based on these analyses, the authors suggest research that could be performed that would ameliorate the uncertainty of choosing a more precise partial UFor that may even provide completeness of database to allow for selecting of a UF for unity, thus improving the precision of the current published RfD.

Animals↗
PubMed2004

An overview of data integration methods for regional assessment.

The U.S. Environmental Protections Agency's (U.S. EPA) Regional Vulnerability Assessment(ReVA) program has focused much of its research over the last five years on developing and evaluating integration methods for spatial data. An initial strategic priority was to use existing data from monitoring programs, model results, and other spatial data. Because most of these data were not collected with an intention of integrating into a regional assessment of conditions and vulnerabilities, issues exist that may preclude the use of some methods or require some sort of data preparation. Additionally, to support multi-criteria decision-making, methods need to be able to address a series of assessment questions that provide insights into where environmental risks are a priority. This paper provides an overview of twelve spatial integration methods that can be applied towards regional assessment, along with preliminary results as to how sensitive each method is to data issues that will likely be encountered with the use of existing data.

Animals↗
PubMed1997

Topics in cancer risk assessment.

The estimation of carcinogenic risks from exposure to chemicals has become an integral part of the regulatory process in the United States within the past decade. With it have come considerable controversy and debate over the scientific merits and shortcomings of the methods and their impact on risk management decisions. In this paper we highlight selected topics of current interest in the debate. As an indication of the level of public concern, we note the major recent reports on risk assessment from the National Academy of Sciences and the U.S Environmental Protection Agency's proposed substantial revisions to its Guidelines for Carcinogen Risk Assessment. We identify and briefly frame several key scientific issues in cancer risk assessment, including the growing recognition of the importance of understanding the mode of action of carcinogenesis in experimental animals and in humans, the methodologies and challenges in quantitative extrapolation of cancer risks, and the question of how to assess and account for human variability in susceptibility to carcinogens. In addition, we discuss initiatives in progress that may fundamentally alter the carcinogenesis testing paradigm.

Animals↗
PubMedDate not supplied

A simple method for evaluating data from an interlaboratory study.

Large-scale laboratory- and method-performance studies involving more than about 30 laboratories may be evaluated by calculating the HORRAT ratio for each test sample (HORRAT = [experimentally found among-laboratories relative standard deviation] divided by [relative standard deviation calculated from the Horwitz formula]). The chemical analytical method is deemed acceptable per se if HORRAT approximately 1.0 (+/- 0.5). If HORRAT is > or approximately 2.0, the most extreme values are removed successively until an "acceptable" ratio is obtained. The laboratories responsible for the extreme values that are removed should examine their technique and procedures. If > or approximately 15% of the values have to be removed, the instructions and the methods should be examined. This suggested computation procedure is simple and does not require statistical outlier tables. Proposed action limits may be adjusted according to experience. Data supporting U.S. Environmental Protection Agency method 245.1 for mercury in waters (manual cold-vapor atomic absorption spectrometry), supplemented by subsequent laboratory-performance data, were reexamined in this manner. Method-performance parameters (means and among-laboratories relative standard deviations) were comparable with results from the original statistical analysis that used a robust biweight procedure for outlier removal. The precision of the current controlled performance is better by a factor of 4 than that of estimates resulting from the original method-performance study, at the expense of rejecting more experimental values as outliers.

Chemistry Techniques, Analytical↗
PubMed1990

EPA's control technology approach to assisting states and regions with air toxics problems: five case studies.

The Environmental Protection Agency (EPA) announced in June 1985 a new strategy to reduce public exposure to toxic air pollutants in the ambient air. Over the next 5-8 years, the strategy called for State and Local authorities to take on more of the lead regulatory role, with the Agency providing technical and financial assistance to their efforts. The shift in emphasis and responsibility from the Federal level to State and Local air toxics programs and the need to transfer expertise from the Federal level to the appropriate State or Local level prompted EPA's Office of Research and Development (ORD) and EPA's Office of Air Quality Planning and Standards (OAQPS) to develop and implement an innovative technical assistance program. This program is called the Control Technology Center (CTC). It has since been expanded to include technical assistance in the area of control of air toxics, particulate matter, and volatile organic compounds (VOCs); emission measurements; and other areas where expertise is available to ORD and OAQPS. During the CTC's first year of operation, operating guidelines were developed and three categories of technical assistance were established. These categories are telephone HOTLINE calls, direct engineering assistance, and technical guidance projects. The CTC HOTLINE is a special telephone number which State and Local Agencies can call for easy access to EPA personnel who can provide prompt assistance in a variety of ways including discussions, references to pertinent literature, and referrals to other EPA personnel. In some cases, a HOTLINE call will require more in-depth engineering analysis indicating a need for direct engineering assistance. These projects tend to be short-term (2 to 3 months) and specific in nature. In some cases, several agencies may indicate a need for information on the same source, or a group of Agencies may make a joint request. In these cases, the CTC Steering Committee, a group who advises the CTC managers, may decide that a technical guidance project is indicated. Technical guidance projects are longer-term and are intended to be of broad interest, useful to many agencies. This paper discusses the development of the CTC, experience to date with its operation, and future plans. In addition, five CTC projects are discussed to illustrate the assistance provided.

Air Pollutants↗
PubMed2006

Determination of perchlorate in drinking water by ion chromatography using macrocycle-based concentration and separation methods.

Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.

Chromatography, Ion Exchange↗
PubMed1992

Environmental justice, regulation, and the local community.

This article examines the sociological significance of the concept of "environmental justice" for grassroots groups responding to toxic contamination in their local communities. Taking into account nationwide mobilization patterns in such communities, the author documents a precedent-setting episode in the city of Jacksonville, Arkansas, where citizen protests and support from national environmental groups led the Environmental Protection Agency to withdraw three Technical Assistance Grants inappropriately awarded to a group with links to a polluting industry, and subsequently to rewrite the rules for participation in such grants. As the first such challenge nationally, the Jacksonville scenario is an important "test case" and permits a theoretical and practical evaluation of the relationship between social groups, technology, and the governmental regulatory process. More particularly, it gives insight into the Technical Assistance Grants program, which was set up to enable citizens living close to contaminated sites to interpret and evaluate technical information relating to such sites, but which has been undercut by a weak EPA and cooptation efforts by industries. The article concludes with an exploration of the concept of community in relation to the new construction of environmental justice engaged in by grassroots groups fighting contamination locally and nationally.

Arkansas↗
PubMed2002

Development of a research strategy for integrated technology-based toxicological and chemical evaluation of complex mixtures of drinking water disinfection byproducts.

Chemical disinfection of water is a major public health triumph of the 20th century. Dramatic decreases in both morbidity and mortality of waterborne diseases are a direct result of water disinfection. With these important public health benefits comes low-level, chronic exposure to a very large number of disinfection byproducts (DBPs), chemicals formed through reaction of the chemical disinfectant with naturally occurring inorganic and organic material in the source water. This article provides an overview of joint research planning by scientists residing within the various organizations of the U.S. Environmental Protection Agency Office of Research and Development. The purpose is to address concerns related to potential health effects from exposure to DBPs that cannot be addressed directly from toxicological studies of individual DBPs or simple DBP mixtures. Two factors motivate the need for such an investigation of complex mixtures of DBPs: a) a significant amount of the material that makes up the total organic halide and total organic carbon portions of the DBPs has not been identified; and b) epidemiologic data, although not conclusive, are suggestive of potential developmental, reproductive, or carcinogenic health effects in humans exposed to DBPs. The plan is being developed and the experiments necessary to determine the feasibility of its implementation are being conducted by scientists from the National Health and Environmental Effects Research Laboratory, the National Risk Management Research Laboratory, the National Exposure Research Laboratory, and the National Center for Environmental Assessment.

Chemistry Techniques, Analytical↗