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 1,279 records · Page 71Linked to original sources
PubMed2000

Radon in Wisconsin.

Owners of about 15% to 20% of the homes in Wisconsin have tested their indoor air for the carcinogenic gas radon. Five percent to 10% of homes have year-average main-floor radon levels that exceed the US Environmental Protection Agency (EPA) exposure guideline, and they are found in most regions of the state. Attempting to retroactively seal foundations to keep radon from the ground out of a home is largely ineffective. However, a soil-depressurization radon mitigation system is highly effective for existing houses, and new homes can easily be built radon-resistant. As the number of homeowners obtaining needed repairs increases, significant lung cancer risk reduction is being achieved in a voluntary, non-regulatory setting. In coming years, as radon in community drinking water supplies becomes regulated under the federal 1996 Safe Drinking Water Act, the "multimedia" option of the act may result in additional attention to mitigation of radon in indoor air.

Carcinogens, Environmental↗
PubMed1990

The risk of nitrogen dioxide: what have we learned from epidemiological and clinical studies?

Nitrogen dioxide (NO2) is an oxidant gas which contaminates ambient air in many urban and industrial locations, and indoor air in homes with combustion appliances. The Environmental Protection Agency presently regulates NO2 in ambient air as a "criteria" pollutant. In spite of decades of laboratory, clinical, and epidemiological research, the health effects of NO2 exposure on humans are not well understood. The toxicological evidence suggests that increased susceptibility to infection, functional deficits from effects on airways, and deterioration of the status of persons with chronic respiratory conditions, including asthmatics, are of potential concern. This paper provides a perspective on the present evidence related to human health effects of NO2. It addresses methodological barriers that limit the available data; assesses the adequacy of the data for risk assessment; and proposes a research agenda to obtain needed information on the health effects of NO2.

Air Pollutants↗
PubMed1991

Conservatism in maximally exposed individual (MEI) predictive exposure assessments: a first-cut analysis.

The United States Environmental Protection Agency (USEPA) sometimes applies exposure assessment models based upon the concept of a hypothetical "maximally exposed individual" (MEI) as a means of dealing with uncertainty. This concept has been described in the benzene NESHAPS rule, the proposed RCRA Corrective Action Rule, and the Clean Air Act reauthorization debate. This paper describes a first-cut analysis of the level of conservatism of the current MEI approach relative to a central estimate of exposure of the most exposed population around a source. The inherent level of conservatism of the current MEI model, which appears to be at least one order of magnitude, is usually left unstated. The significance of this conservatism is described along with some proposals for future research.

Benzene↗
PubMed2004

VOCs in shallow groundwater in new residential/commercial areas of the United States.

The quality of shallow groundwater in urban areas was investigated by sampling 518 monitoring wells between 1996 and 2002 as part of the National Water-Quality Assessment Program of the U.S. Geological Survey. Well networks were installed primarily in new residential/commercial areas less than about 30 years old (17 studies) and in small towns (2 studies) by randomly locating as many as 30 monitoring wells in each study area. The median well depth was 10 m. Based on samples with age-date information, almost all groundwater was recharged after 1950. Samples were analyzed for 53 volatile organic compounds (VOCs). Concentrations ranged from about 0.001 to 1000 microg/L (median 0.04), with less than 1% of the samples exceeding a Maximum Contamination Level or Drinking Water Advisory established by the U.S. Environmental Protection Agency. Using uncensored concentration data, at least one VOC was detected in 88% of the samples, and at least two VOCs were detected in 69% of the samples. Chloroform, toluene, and perchloroethene were the three most frequently detected VOCs. Dissolved oxygen concentration, estimated recharge index, and land-use were significant variables in logistic regression models that explained the presence of the commonly detected VOCs. Dissolved oxygen concentration was the most important explanatory variable in logistic regression models for 6 of the 14 most frequently detected VOCs. Bromodichloromethane, chloroform, and 1,1,1-trichloroethane had a positive correlation with dissolved oxygen; in contrast, dichloroethane, benzene, and toluene had a negative correlation with dissolved oxygen.

Benzene↗
PubMed2003

The association of lead-contaminated house dust and blood lead levels of children living on a former landfill in Puerto Rico.

Exposure to lead in children living on a former landfill in Vega Baja-Puerto Rico, a United States Environmental Protection Agency (USEPA) designated Superfund Site, is a major health concern. Direct contact with lead-contaminated soil is considered a major exposure source. However, there is a lack of information regarding the contribution of lead-contaminated house dust to children's blood lead concentrations. This study evaluated the relationship between lead contaminated-house dust and children's blood lead levels. Blood from 42 children, aged 6 years old or less, and dust from 29 houses were analyzed for lead, and face-to-face interviews were performed to gather information on potential risk factors for high blood lead levels. Blood lead levels ranged from 0.97 to 7.79 micrograms/dL. Lead values for floors fluctuated from 0.12 to 98.30 micrograms/ft2, with 17% of houses surpassing the USEPA standard of 40 micrograms/ft2. Multiple regression analysis showed that lead in window sills, toy chewing and soil eating habits were significant predictors of blood lead levels. Further investigations aimed at assessing the long-term effects of constant exposure to environmental lead in these children are warranted.

Air Pollution, Indoor↗
PubMed2006

Community exposure to asbestos from a vermiculite exfoliation plant in NE Minneapolis.

Western Mineral Products/W. R. Grace operated a vermiculite plant in a mixed industrial/residential area of northeast Minneapolis from 1936 to 1989. The plant processed vermiculite ore contaminated with amphibole asbestos from a mine in Libby, MT. Air monitoring in the early 1970s found fiber concentrations in excess of 10 fibers per cubic centimeter of air (f/cc), indicating that worker exposure to asbestos was occasionally 100 times the current occupational standard. Residents of the surrounding community also had direct contact with vermiculite processing wastes (containing up to 10% amphibole asbestos) that were made freely available. Children played on waste piles and neighborhood residents hauled the wastes away for home use. In total, 259 contaminated residential properties have been found to date. Reported emission factors and plant process data were used as inputs to model airborne emissions from the plant over several operating scenarios using the U.S. Environmental Protection Agency (EPA) ISC-Prime model. Results estimate short-term air concentrations of asbestos fibers in residential areas nearest the plant may have at times exceeded current occupational standards. Exposure estimates for other pathways were derived primarily from assessments done in Libby by the U.S. EPA. The Northeast Minneapolis Community Vermiculite Investigation (NMCVI) was conducted by the Minnesota Department of Health to identify and characterize the exposures of a cohort of over 6000 people who live or lived in Northeast Minneapolis and may have been exposed to asbestos. This cohort is now being investigated in a respiratory health screening study conducted by the University of Minnesota and the Minnesota Department of Health.

Aluminum Silicates↗
PubMed2005

Methodologic and logistic issues in conducting longitudinal birth cohort studies: lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research.

In anticipation of the National Children's Study, lessons can be learned from the smaller birth cohort studies conducted by five Centers for Children's Environmental Health and Disease Prevention Research funded by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency. The populations studied are diverse in ethnicity and social class and reside in urban and rural environments. Although almost all of the centers chose to enroll participants through medical care facilities, they had to develop independent staffs and structures because of the overburdened medical care system. Some of the lessons learned by the centers include the importance of continuous funding, building community partnerships to conduct culturally appropriate research, hiring bilingual and bicultural staff from the community, prioritizing research goals, developing biorepositories to ensure future utility of samples, instituting quality control procedures for all aspects of specimen and data collection, maintaining frequent contact with study participants, ensuring ethical conduct of the research in a changing medical-legal climate, and communicating results in a timely and appropriate manner to participants and the wider community. All centers underestimated the necessary start-up time, staff, and costs in conducting these birth cohort studies. Despite the logistical complexity and added expenses, all centers emphasize the importance of studying the impact of environmental exposures on those children most at risk, those living in minority and low-income communities. These centers present barriers encountered, solutions found, and considerations for future research, with the hope that the lessons learned can help inform the planning and conduct of the National Children's Study.

Adolescent↗
PubMed2003

Dynamics of subcellular compartmentalization of steroid receptors in living cells as a strategic screening method to determine the biological impact of suspected endocrine disruptors.

Although a number of screening methods being used for identifying potential endocrine disruptors have generated a wealth of information, a search for alternative combination of methods is still needed to overcome experimental artefacts. There are no generally accepted or validated screening methods for monitoring and studying impact of environmental endocrine disruptors. Also, no single assay can accurately predict all the deleterious effects of endocrine disruptors. For this reason various environmental protection agencies, mainly European and US, have urged that a battery of tests in current use need to be designed to assess their adequacy in detecting the effects of endocrine disruptors. Some details about endocrine disruptors and screening programs can be found at http://www.epa.gov/scipoly/oscpendo/whatis.htm. Several studies in recent years have used fusion proteins between steroid receptors (estrogen, androgen, progesterone, etc.) and green fluorescent protein (GFP) that can serve as an alternative potent screening method to study intracellular dynamics of receptors in living cells. An approach employing nucleocytoplasmic trafficking of steroid receptors as a parameter in response to potential xenobiotic chemicals in living cells may prove to be promising in terms of being direct, fast, reliable, simple and inexpensive.

Animals↗
PubMed2004

Three-dimensional hydrodynamic-eutrophication model (HEM-3D): application to Kwang-Yang Bay, Korea.

The purpose of this paper is twofold: to describe the water quality model of Three-Dimensional Hydrodynamic-Eutrophication Model (HEM-3D) and to present an application of HEM-3D to a coastal system in Korea. HEM-3D, listed as a tool for the development of Total Maximum Daily Load by US Environmental Protection Agency, is a general-purpose modeling package for simulation of the flow field, transport, and eutrophication processes throughout the water column and of diagenetic processes in the benthic sediment. This paper describes the water quality model of HEM-3D with emphasis on its unique features. Excessive loadings of organic wastes have significantly deteriorated water quality conditions of Korean coastal waters. This paper presents an application of HEM-3D to Kwang-Yang Bay, a coastal system in Korea, which is one of the first water quality modeling efforts for Korean coastal waters accompanied by a relatively comprehensive field program. The current status of data availability for water quality modeling in Korea is discussed.

Environmental Monitoring↗
PubMed1997

Assessment of environmental hazards of 1,3,5-trinitrobenzene.

The remedial investigation/feasibility studies conducted at certain Army installations showed a need to clean up contaminated sites, where high levels of ammunition chemicals such as 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 1,3-dinitrobenzene (DNB), and their degradation products/metabolites were detected in surface soil and groundwater. TNB is a photodegradation product of TNT; it is not easily degraded, and persists in the environment. The toxicity data on TNB are scanty. Hence the U.S. Environmental Protection Agency in 1988 (U.S. EPA, 1997) developed a reference dose (RfD) for TNB (0.00005 mg/kg/d for chronic toxicity) based on the toxicity of DNB, which is structurally similar to TNB. Since then we have completed acute, subacute, subchronic, chronic, reproductive, and developmental toxicity studies and toxicokinetics studies. We have reviewed the mammalian toxicity data for TNB and have determined the no observed adverse effect levels (NOAEL) and low observed adverse effect levels (LOAEL) for subchronic, chronic, reproductive, and developmental toxicity. Based on the newly determined NOAEL and LOAEL values, we have now developed a new RfD for TNB (0.03 mg/kg/d), based on the chronic toxic effects on hematology and histopathological changes in testes and kidney.

Administration, Oral↗
PubMedDate not supplied

Comparative evaluation of conventional and alternative methods for the removal of arsenic from contaminated groundwaters.

The present paper intends to summarize the recent findings regarding the development of alternative treatment methods applicable to small municipal drinking water systems. Small systems are frequently affected by the new permissible arsenic concentration rules, as imposed by several international organizations-World Health Organization, European Commission, United States Environmental Protection Agency. The innovate treatment methods reviewed are (a) adsorptive filtration, using iron oxide coated sand or polymeric materials; (b) zero-valent iron; (c) solar disinfection, solar oxidation and removal of arsenic (SORAS); (d) iron-based adsorbents, such as granular ferric hydroxide (GFH); (e) biological oxidation and removal of arsenic, accomplished simultaneously with the biological iron oxidation. In addition, other more conventional methods for arsenic removal are also discussed, such as iron or alum coagulation, lime softening, ion exchange, activated alumina and membrane separation processes. The aforementioned methods have been comparatively evaluated and the relevant conclusions have been drawn with respect to the applicability of arsenic treatment methods, depending on certain parameters, such as locally varying water quality characteristics, sustainability, and economic feasibility.

Arsenic↗
PubMed2004

Aerobic dechlorination of cis- and trans-dichloroethenes by some indigenous bacteria isolated from contaminated sites in Africa.

The innate toxicity of dichloroethenes (DCEs) and their tendency to be reduced to vinyl chloride (VC) (a known human carcinogen) is a cause for environmental concern. Aerobic bacteria capable of growth on cis- and trans-DCEs as sole carbon and energy sources were isolated by enrichment culture technique and identified to belong to the genera; Bacillus, Pseudomonas and Acinetobacter. Axenic and mixed cultures of the bacterial isolates utilized DCEs at concentrations above the maximum contaminant level allowable in drinking water by the Environmental Protection Agency. Their specific growth rate constant ranged significantly (P < 0.05) between 0.346-0.552 and 0.461-0.667 d(-1); while the maximum specific substrate utilization rate ranged significantly (P < 0.05) between 20.01-29.79 and 31.40-42.83 nmol h(-1) (mg of protein)(-1) in cis- and trans-DCE, respectively. The optimum growth was observed at 30 degrees C and at a pH of 7.0 with up to 96% of the stoichiometric-expected chloride released. Serial adaptation positively affected the growth yields and dehalogenase activities of the organisms with multiple antibiotic patterns also demonstrated by the isolates. These findings therefore indicated the important roles that these organisms may play in the bioremediation of sites polluted with chlorinated ethene compounds in Africa.

Bacteria, Aerobic↗
PubMed2006

[Determination of 16 PAHs from atmospheric particulate matter PM2.5 in certain ironworks district by HPLC].

The paper describes the determination of the 16 polycyclic aromatic hydrocarbons (PAHs) prescribed by Environmental Protection Agency in PM2.5 in certain ironworks district of Beijing by HPLC. A HPLC method of VWD-FLD connected in series was founded. The 16 PAHs were completely separated by the method. The earlier eluted ten PAHs were detected by VWD and the rest were detected by FLD. The minimum detection limits of the 16 PAHs vary from 0.29 microg x L(-1) (for Bkf) to 50.6microg x L(-1) (for Nap), the average recoveries range between 85.1% (for Nap) and 103.2% (for Fla) and the relative standard deviations are between 4.31% (for Flu) and 9.93% (for Ind). The detection results indicate that the pollution situation is still very serious in this district.

Air Pollutants↗
PubMed2001

Development of a freshwater aquatic toxicity database for ambient water quality criteria for methyl tertiary-butyl ether.

The detection of methyl tertiary-butyl ether (MTBE) in groundwater and surface water in recent years has drawn attention to its potential effects in aquatic ecosystems. To address concerns regarding MTBE environmental effects and to establish safe concentrations in surface waters, a collaborative effort was initiated in 1997 to develop aquatic toxicity databases sufficient to derive ambient water quality criteria for MTBE consistent with United States Environmental Protection Agency (U.S. EPA) requirements. Acute toxicity data for six species, chronic toxicity data for a fish and an invertebrate, and plant toxicity data were developed in order to complete the freshwater database. The toxicity tests followed U.S. EPA and American Society for Testing and Materials (ASTM, Philadelphia, PA, USA) procedures and were conducted in accordance with U.S. EPA Good Laboratory Practice guidelines. Based on measured exposure concentrations, acute toxicity endpoints ranged from 472 to 1742 mg MTBE/L, while chronic endpoints (IC25) were 57 to 308 mg MTBE/L. Aquatic invertebrates were generally more sensitive than fish to MTBE in both acute and chronic exposures. Acute-to-chronic ratios for fathead minnows and Daphnia magna were 3.4 and 11.3, respectively. The measured acute and chronic toxicity were within a 10-fold factor of toxicity predicted from quantitative structure-activity relationships for baseline toxicity or nonpolar narcosis typical of ether compounds. The data developed in this study were consistent with existing data and showed that MTBE has low acute and chronic toxicity to freshwater organisms. Reported environmental concentrations of MTBE are several orders of magnitude lower than concentrations observed to cause effects in freshwater organisms.

Database Management Systems↗
PubMed2006

Assessment and management of residential radon health risks: a report from the health Canada radon workshop.

Epidemiologic studies of uranium miners and other underground miners have consistently shown miners exposed to high levels of radon to be at increased risk of lung cancer. More recently, concern has arisen about lung cancer risks among people exposed to lower levels of radon in homes. The current Canadian guideline for residential radon exposure was set in 1988 at 800 Bq/m(3). Because of the accumulation of a considerable body of new scientific evidence on radon lung cancer risks since that time, Health Canada sponsored a workshop to review the current state-of-the-science on radon health risks. The specific objectives of the workshop were (1) to collect and assess scientific information relevant to setting national radon policy in Canada, and (2) to gather information on social, political, and operational considerations in setting national policy. The workshop, held on 3-4 March 2004, was attended by 38 invited scientists, regulators, and other stakeholders from Canada and the United States. The presentations on the first day dealt primarily with scientific issues. The combined analysis of North American residential radon and lung cancer studies was reviewed. The analysis confirmed a small but detectable increase in lung cancer risk at residential exposure levels. Current estimates suggest that radon in homes is responsible for approximately 10% of all lung cancer deaths in Canada, making radon the second leading cause of lung cancer after tobacco smoking. This was followed by a perspective from an UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) working group on radon. There were two presentations on occupational exposures to radon and two presentations considered the possibility of radon as a causative factor for cardiovascular disease and for cancer in other organs besides the lung. The possible contribution of environmental tobacco smoke to lung cancers in nonsmokers was also considered. Areas for future research were identified. The second day was devoted to policy and operational issues. The presentations began with a perspective from the U.S. Environmental Protection Agency, followed by a history of radon policy development in Canada. Subsequent presentations dealt with the cost-effectiveness of radon mitigation, Canadian building codes and radon, and a summary of radon standards from around the world. Provincial representatives and a private consultant were given opportunities to present their viewpoints. A number of strategies for reducing residential radon exposure in Canada were recognized, including testing and mitigation of existing homes (on either a widespread or targeted basis) and changing the building code to require that radon mitigation devices be installed at the time a new home is constructed. The various elements of a comprehensive national radon policy were set forth.

Air Pollutants, Radioactive↗
PubMed1999

Environmental contamination and human exposure to manganese--contribution of methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline.

The organomanganese compound MMT (methylcyclopentadienyl manganese tricarbonyl), an antiknock additive in unleaded gasoline, has been used in Canada since 1976. Indeed, Canada is the only country where MMT is almost exclusively used. In October 1995, by court decision the Environmental protection Agency (EPA) granted Ethyl's waiver for the use of MMT in the United States. Paradoxically, in 1997 the federal government of Canada adopted a law (C-29) that banned both the interprovincial trade and the importation for commercial purposes of manganese-based substances, including MMT. However, MMT is currently widely used in Canada because of substantial stockpiling, and six Canadian provinces are challenging the law in the courts. Moreover, MMT has been approved for use in Argentina, Australia, Bulgaria, Russia, and conditionally, in New Zealand. It has been suggested by some scientists that combustion of MMT may be a significant source of exposure to inorganic Mn in urban areas. The crucial question is whether Mn contamination from industrial sources combined with the additional contamination that would result from the widespread use of MMT would lead to toxic effects. Our research efforts have attempted to assess the environmental/ecosystem Mn contamination arising from the combustion of MMT in abiotic and biotic systems as well as human exposure. The experimental evidence acquired so far provides useful information on certain environmental consequences of the use of MMT as well as raising a number of questions. Our results gave evidence indicating that roadside air, soils, plants, and animals may be contaminated by Mn. As well, some specific groups of the population could have a higher level of exposure to Mn. Nevertheless, the levels of exposure remain below international guide values. Further studies and further characterization of dose-response relationships are thus needed to provide successful implementation of evidence-based risk-assessment approaches.

Canada↗
PubMed1991

Application of biological data in cancer risk estimations of chlordane and heptachlor.

Regulatory agencies traditionally use doses associated with ambient concentrations of contaminants in environmental media to estimate lifetime excess cancer risks. This approach is, however, limited by the errors inherent in making several default assumptions such as daily water and food intakes and organ absorption factors. A methodology was developed in this study to estimate daily human doses of chlordane and heptachlor from measured metabolites in adipose tissue. Human biomonitoring data, pharmacodynamic and pharmacokinetic parameters in humans and animals, and selected dose-response data from animal carcinogenicity studies were utilized in this procedure for cancer risk assessment in man. Conversion factors, based on body surface area, were used for animal-to-man extrapolation. Conservative estimates from the Global 82 linearized multistage mathematical model (95% upper confidence limit) associate a 1 x 10(-5) risk probability level to chlordane and heptachlor doses of 1.1 x 10(-4) and 4.0 x 10(-5) mg/kg-day, respectively, via all potential routes of exposure. The unit cancer risks associated with "internal" dose estimates from human adipose tissue concentrations were calculated and compared with U.S. Environmental Protection Agency (1986a, Carcinogenicity Assessment of Chlordane and Heptachlor/Heptachlor Epoxide, EPA-600/6-87-004) unit risks in air and water. The implications and uncertainties associated with the risk estimates were also discussed.

Animals↗
PubMed2003

Assessment of PCB congener analytical methods: do they meet risk assessment needs?

Congener-specific PCB analysis allows use of toxic equivalency (TEQ) TCDD-based risk assessment approaches when analytical methods are sufficiently sensitive. Many efforts to analyze fish samples for PCB congeners report the majority of samples as non-detects; these data are of little use for human health risk assessment if the limits of analytical detection exceed levels of potential health concern. However, increasing analytical sensitivity is costly and technically difficult. An approach to assess analytical sensitivity needs for risk assessment by defining toxicological endpoints of concern and acceptable risk levels is presented. This framework was applied to assessment of potential PCB TEQ cancer risks to the general United States population and tribal consumers of Columbia River fish, but may be easily adjusted for other situations. A probabilistic model was used to calculate the necessary analytical sensitivity for PCB TEQ cancer risk assessment using the Environmental Protection Agency's new draft cancer risk slope factor for TCDD and fish consumption data. Desired levels of analytical sensitivity were estimated for the congener expected to contribute the most to PCB TEQ, PCB 126, and compared to limits of detection for various analytical methods. The financial and health value of methods with different levels of analytical sensitivity were compared using a value of information approach, which includes analytical cost and cost of potential health outcomes, and a proposed risk assessment utility approach which considers the relative health protectiveness of analytical options non-monetarily. Sensitivity analyses indicate that average consumption rate, cancer risk slope factor choice, and knowledge of existing PCB contamination are important considerations for planning PCB congener analysis.

Animals↗