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At least 775 records · Page 43Linked to original sources
PubMed2002

Inhibition of gap-junctional intercellular communication by environmentally occurring polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are a broad class of ubiquitous environmental pollutants with known or suspected carcinogenic properties. Tumor promotion is a cell-proliferative step of cancer that requires the removal of cells from growth suppression via the inhibition of gap-junctional intercellular communication (GJIC). Inhibition of GJIC measured with an in vitro WB-F344 rat liver epithelial cell system was used to assess the relative potencies of 13 PAHs suggested by the U.S. Environmental Protection Agency (EPA) as the principal contaminants and 22 other PAHs, most of them identified in environmental samples. Maximal inhibition of GJIC was detected after 30 min of exposure, followed by a recovery in intercellular communication after an additional 30 min of exposure, suggesting a transient character of inhibition. Although microM concentrations of PAHs were required to reach the inhibition level equal to the model tumor promoter phorbol 12-myristate 13-acetate (IC50 = 8 nM), 12 of the PAHs under study were found to be strong inhibitors of GJIC (strongest effects were observed with fluoranthene, picene, 5-methylchrysene and nine additional PAHs). The other nine PAHs, including benzo[a]pyrene, inhibited GJIC only up to 50-75% of the control level. Interestingly, several high molecular weight PAHs with known strong carcinogenic properties possessed only weak (dibenzopyrenes) or no inhibition potency (dibenzofluoranthenes, naphtho[2,3-a]pyrene and benzo[a]perylene). Based on the IC50 values related to the reference PAH benzo[a]pyrene, we suggested arbitrary values of inhibition equivalency factors (GJIC-IEFs) ranging from 0 (noninhibiting PAHs) to 10.0 (strongest inhibitors), suitable for the purposes of environmental risk assessment.

Animals↗
PubMed1994

Evaluating health risks from occupational exposure to pesticides and the regulatory response.

In this study, we used measurements of occupational exposures to pesticides in agriculture to evaluate health risks and analyzed how the federal regulatory program is addressing these risks. Dose estimates developed by the State of California from measured occupational exposures to 41 pesticides were compared to standard indices of acute toxicity (LD50) and chronic effects (reference dose). Lifetime cancer risks were estimated using cancer potencies. Estimated absorbed daily doses for mixers, loaders, and applicators of pesticides ranged from less than 0.0001% to 48% of the estimated human LD50 values, and doses for 10 of 40 pesticides exceeded 1% of the estimated human LD50 values. Estimated lifetime absorbed daily doses ranged from 0.1% to 114,000% of the reference doses developed by the U.S. Environmental Protection Agency, and doses for 13 of 25 pesticides were above them. Lifetime cancer risks ranged from 1 per million to 1700 per million, and estimates for 12 of 13 pesticides were above 1 per million. Similar results were obtained for field workers and flaggers. For the pesticides examined, exposures pose greater risks of chronic effects than acute effects. Exposure reduction measures, including use of closed mixing systems and personal protective equipment, significantly reduced exposures. Proposed regulations rely primarily on requirements for personal protective equipment and use restrictions to protect workers. Chronic health risks are not considered in setting these requirements. Reviews of pesticides by the federal pesticide regulatory program have had little effect on occupational risks. Policy strategies that offer immediate protection for workers and that are not dependent on extensive review of individual pesticides should be pursued.

Adult↗
PubMed1995

Relevance of risk assessment to exposed communities.

Current environmental policy tends to evaluate potential, theoretical exposure to health risks by evaluating one chemical or hazard at a time. Risk assessment techniques used by the U. S. Environmental Protection Agency (EPA) and other government agencies do not evaluate the cumulative impact of exposure to environmental contaminants. This problem is of particular significance to low-income and minority populations who tend to live in neighborhoods and work in locations that involve exposure to pollutants in air, water, and workplace activity. Certain areas within the border typify this lifestyle. The problem is further complicated by the fact that EPA operates separate programs for different "media." Exposure patterns in the border suggest the need for a cross-media pollution prevention approach. Minority recruitment into health research, a coordination of research approaches and dollars, and new resources for effective monitoring of minority communities could provide a basic assessment of the risks and their sources. Further research into the cumulative impacts of prevalent subsets of chemicals is also needed. Recent efforts in the Great Lakes may provide a model for this type of regional, cross-border effort.

Community Health Planning↗
PubMed2003

A critical evaluation of public health programs at the Bunker Hill Superfund site.

Since 1983, the Bunker Hill Superfund site (BHSS) has been the second largest on US Environmental Protection Agency's (EPA) National Priority List for cleanup. Contaminants include millions of tons of Pb, Cd, Hg and As. In 1974, following a bag house fire, 22.1% of young children had blood lead levels >80 microg/dl. In the early 1980s to the present, EPA initiated the cleanup of exterior residential soils and the smelter complex. In 1999, The National Geological Service confirmed that heavy metal pollution had extended from BHSS to Lake Coeur d'Alene (already known earlier) all the way to the Spokane River in Washington State via water borne tributaries linking Idaho and Washington States. This report focuses on public health programs and their results initiated by Federal and State agencies at the BHSS. These programs include blood lead screening, educational programs, exploratory dust control plans, and land transactions. These programs and their results are then evaluated, assessed and critically discussed. The conclusion of this critical evaluation assessment is that the protection of public health has not been adequately addressed or protected by Federal and State agencies.

Child↗
PubMed2004

Appropriate preservation of dairy wastewater samples for environmental analysis.

Thousands of gallons of water are used in dairies to wash cows before milking and for cleaning equipment. The wastewater generated contains elevated levels of organic matter and pollutants, including nitrogen that once converted, may contaminate groundwater with nitrate. This study was conducted to determine the amount of sulfuric acid needed to preserve wastewater samples from a New Mexico dairy in the southwestern U.S. Titrations of wastewater from a local dairy using full strength (18 M) sulfuric acid were performed to determine the amount of acid needed to bring the pH of the sample to below two, the recommended pH for sample preservation. An average of 0.33 mL of acid was required for every 100 mL of wastewater. Due to sample variability, we recommend that 0.4 mL sulfuric acid be added for every 100 mL dairy wastewater sample to ensure adequate acidification. This quantity is twice the amount currently recommended in U.S. Environmental Protection Agency guidelines.

Dairying↗
PubMed2003

Communicating air quality information: experimental evaluation of alternative formats.

A long-running effort in environmental communication is daily publication of a report on local air pollution in many American newspapers based on the Pollutant Standards Index (PSI). A 1998 proposal by the U.S. Environmental Protection Agency (U.S. EPA) to change the PSI prompted a survey experiment with 1,100 adults in Philadelphia, evaluating the proposed change's ability to better inform the populace. The effects of exposure to the old and new versions of the PSI, as well as health cautions and information about groups sensitive to air pollution, were compared with evaluation criteria suggested by Weinstein and Sandman (1993). Sample respondents had strong baseline concerns about air pollution. Descriptors of air quality (e.g., "good; " "unhealthy") were difficult to discriminate, particularly in the New format. Concern rose as hypothetical air pollution levels rose, but the New format (as well as PSI versions without health cautions or sensitive-group information) evoked a sharp discontinuity in concern between below- and above-standard pollution levels. Both Old and New formats reduced concern relative to no provision of PSI information at all, but the New format reduced concern significantly more than the Old version. No PSI format did particularly well at increasing knowledge of air pollution or decreasing intentions to be active outdoors during high pollution, contrary to the agency's aim. Although U.S. EPA has since adopted the new proposal as a national "Air Quality Index" requirement, the experiment's results illuminate the strengths and limitations of the new PSI as a means of informing citizens and motivating them to protect themselves.

Air Pollution↗
PubMed1995

Using the EPC approach to develop health-based soil and water screening concentrations for environmental chemicals.

Reference doses (RfDs) and reference concentrations (RfCs) developed by the United States Environmental Protection Agency (USEPA) are typically used to assess the risk of potential adverse human health effects from exposure to environmental chemicals. For a large number of chemicals, however, USEPA RfDs or RfCs have not yet been determined. Thus, for risk assessments that involve a large number of chemicals, there may not be USEPA- or state-derived toxicity constants for all chemicals present at a particular site. A potential solution to this problem is to use estimated permissible concentrations (EPCs) to develop acceptable daily dosages from occupational exposure limits. The EPC is defined as the concentration of a chemical which, under continuous exposure conditions, is expected to be devoid of all acute and chronic toxicities. EPC values are based on allowable occupational exposure limits such as threshold limit values (TLVs), which are workplace exposure guidelines suggested by the American Conference of Governmental Industrial Hygienists. In the present analysis, the EPC method was used to develop interim toxicity constants for more than 30 chemicals which possess TLVs and which appear in the Appendix VIII Hazardous Constituents list, but for which the USEPA has not yet assigned a current RfD or RfC. Appendix VIII chemicals are commonly found at hazardous waste and other sites. Consequently, the development of toxicity constants for the more than 30 chemicals on this list would prove to be most useful for risk assessment purposes. These toxicity constants were then used, together with standard exposure assumptions, to develop acceptable human health-based soil and water concentrations for these chemicals. The use of these values as interim guidance would therefore allow individuals responsible for assessing human health effects posed by environmental contamination to address all site chemicals without performing extensive, chemical-specific toxicological analyses.

Adolescent↗
PubMedDate not supplied

Data quality objectives in environmental research planning.

This paper presents highlights of a Data Quality Objectives course relating the Environmental Protection Agency's (EPA) seven step research planning process to research efforts at the U.S. EPA National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, in Duluth, Minnesota. Introductory materials were derived from "Guidance for the Data Quality Objectives Process, EPA QA/G-4." Case studies illustrate decisions that were made during the systematic planning process and subsequent experimentation. This paper demonstrates how the Data Quality Objectives Process clearly links research goals and objectives with the final product. Application of the process to environmental research ensures that environmental research data are of known, credible, defensible and usable quality.

Animals↗
PubMed2002

Comparison of inductively coupled plasma-mass spectrometry and radiochemical techniques for total uranium in environmental water samples.

Inductively coupled plasma-mass spectrometry (ICP-MS) method EPA 200.8 is gradually finding acceptance as an alternative to uranium analysis. A comparison of the ICP-MS with the accepted radiochemical method EPA 908.0 has been carried out based on data from laboratory control standards, national proficiency test samples, and environmental and drinking water samples from the State of Utah. The method detection limit (MDL) for ICP-MS was determined to be 0.017 microg/L or (0.011 pCi/L), and the minimum reporting limit (MRL) was 0.17 microg/L (MDL x 10) or (0.11 pCi/L). The minimum reporting limit for radiochemical 908.0 method is 1 pCi/L. Our spiked matrix recoveries, spiked blank samples, and reference materials deviate only a few percentage from the listed true values. Results demonstrate that the ICP-MS is a superior analytical tool for the determination of uranium in drinking and environmental waters at concentrations required by the United States Environmental Protection Agency.

Mass Spectrometry↗
PubMed1994

The EPC approach to estimating safety from exposure to environmental chemicals.

Reference doses (RfDs) and reference concentrations (RfCs) developed by the United States Environmental Protection Agency (USEPA) are typically used in the quantitation of risk of potential adverse human health effects from exposure to environmental chemicals. For a large number of chemicals, however, USEPA RfDs and RfCs have not yet been determined. Thus, for risk assessments that involve a large number of chemicals, there is insufficient toxicity information with which to evaluate potential adverse human health effects for all chemicals present at a particular site. Due to this insufficiency, the risk assessor must either (1) ignore potential exposures on the assumption that omitting these exposures does not significantly alter decisions concerning the remediation of the site or (2) undertake a lengthy and costly analysis to generate the necessary RfDs or RfCs. A potential solution to this problem is to develop estimated permissible concentrations (EPCs), values which represent permissible environmental concentrations or related acceptable daily dosages derived from occupational exposure limits. In the present analysis, acceptable daily dosages determined using the EPC method were compared to USEPA RfDs or RfCs which were converted to dosages based on standard exposure assumptions. Based on a comparative analysis of EPCs and USEPA reference values for 103 chemicals, it was found that EPC daily dosages represent a reasonably conservative surrogate value when USEPA or state reference values are unavailable. Given that there are hundreds of chemicals with occupational exposure limits but no state or USEPA reference values, acceptance of the EPC methodology would provide an interim solution for the problem of insufficient toxicity information for a substantial number of environmental chemical contaminants.

Animals↗
PubMed2003

Mass-selected resonance-enhanced multiphoton ionisation spectra of laser-desorbed molecules for environmental analysis: 16 representative polycyclic aromatic compounds.

Mass-selected gas-phase UV spectra of laser-desorbed molecules at room temperature have been measured via resonance-enhanced multiphoton ionisation (REMPI) and time-of-flight mass selection. The wavelength range of 260 to 320 nm is optimal for detection of polycyclic aromatic hydrocarbons (PAHs) using REMPI-mass spectrometry. A new laser desorption/laser ionisation source has been used which features a compact size and thermal equilibrium of the desorbed molecules. 16 PAHs have been investigated which have been selected by the US Environmental Protection Agency (EPA). These 16 EPA-PAHs are commonly used world-wide to characterise the PAH-load of environmental samples.

Environmental Monitoring↗
PubMed2005

Aging and the environment: a research framework.

The rapid growth in the number of older Americans has many implications for public health, including the need to better understand the risks posed to older adults by environmental exposures. Biologic capacity declines with normal aging; this may be exacerbated in individuals with pre-existing health conditions. This decline can result in compromised pharmacokinetic and pharmacodynamic responses to environmental exposures encountered in daily activities. In recognition of this issue, the U.S. Environmental Protection Agency (EPA) is developing a research agenda on the environment and older adults. The U.S. EPA proposes to apply an environmental public health paradigm to better understand the relationships between external pollution sources --> human exposures --> internal dose --> early biologic effect --> adverse health effects for older adults. The initial challenge will be using information about aging-related changes in exposure, pharmacokinetic, and pharmacodynamic factors to identify susceptible subgroups within the diverse population of older adults. These changes may interact with specific diseases of aging or medications used to treat these conditions. Constructs such as "frailty" may help to capture some of the diversity in the older adult population. Data are needed regarding a) behavior/activity patterns and exposure to the pollutants in the microenvironments of older adults; b) changes in absorption, distribution, metabolism, and excretion with aging; c) alterations in reserve capacity that alter the body's ability to compensate for the effects of environmental exposures; and d) strategies for effective communication of risk and risk reduction methods to older individuals and communities. This article summarizes the U.S. EPA's development of a framework to address and prioritize the exposure, health effects, and risk communications concerns for the U.S. EPA's evolving research program on older adults as a susceptible subpopulation.

Aged↗
PubMed1993

Reducing the risks from radon.

The U.S. Environmental Protection Agency estimates that residential radon levels in the United States lead to approximately 13,600 lung cancer deaths per year. To address this problem, the Agency has identified three program initiatives that can provide substantial reductions in the public's risks: (1) public information activities that urge the public to test for radon and reduce elevated concentrations in existing homes, (2) new construction standards to reduce radon entry, and (3) radon testing and mitigation during real estate transactions. This paper analyzes the costs and risk reductions that could result from the implementation of these major initiatives, showing how all three elements cost-effectively protect the public's health.

Construction Materials↗
PubMedDate not supplied

Endocrine modulators: risk characterization and assessment.

Over the last several years, information has been accumulating that suggests that adverse effects are being induced in certain wildlife species, and perhaps also in humans, as a consequence of exposure to man-made chemicals that have been released into the environment. Many of these effects have been attributed to interactions with various hormone systems in endocrine tissues. Most often the effects observed have been effects on reproduction and development, although there are also (often conflicting) data regarding an association between exposure and certain kinds of cancer, particularly cancers of reproductive tissues such as breast and testis; effects on the immune system have also been noted. The substances to which these attributes have been ascribed have come to be known as "endocrine modulators" or "endocrine disruptors." The full nature and scope of the "problem" of endocrine modulators/disruptors is currently a matter of great debate, both within and outside of the scientific community. Regulatory authorities around the world are being asked what their position is on this issue and what, if any, regulatory strategies they are developing to address the problem. In many cases, because of the nature of the legislation under which governments manage chemicals, regulatory decisions must be informed by risk assessment. This presentation will describe the general approach to the risk assessment of endocrine modulators/disruptors as practiced by the US government, with particular focus on the current practices/policies of the US Environmental Protection Agency.

Animals↗
PubMedDate not supplied

Toxicological and environmental health information from the National Library of Medicine.

The National Library of Medicine's Toxicology and Environmental Health Information Program is the outgrowth of a 1966 document on "Handling of Toxicological Information," prepared by the Presidents Science Advisory Committee (National Library of Medicine, 1995). The Toxicology and Environmental Health Program is responsible for the creation and deployment of both bibliographic and factual files concerned with toxicology, carcinogenesis, developmental and reproductive effects of chemical substances, toxic chemical releases, and the medical and environmental behavior of chemical substances. The two main computer systems that provide bibliographic and factual data banks are Toxicology Data Network (TOXNET) and ELHILL. A number of the files found in the TOXNET system are built and maintained by other federal agencies such as the National Cancer Institute, the U.S. Environmental Protection Agency, the National Institute for Occupational Safety and Health.

Animals↗
PubMed1999

Resolution of the long-term performance issues at the Waste Isolation Pilot Plant.

The Waste Isolation Pilot Plant (WIPP) is a geological repository for disposal of U.S. defense transuranic radioactive waste. Built and operated by the U.S. Department of Energy (DOE), it is located in the Permian age salt beds in southeastern New Mexico at a depth of 655 m. Performance assessment for the repository's compliance with the 10,000-year containment standards was completed in 1996 and the U.S. Environmental Protection Agency (EPA) certified in 1998 that the repository meets compliance with the EPA standards 40 CFR 191 and 40 CFR 194. The Environmental Evaluation Group (EEG) review of the DOE's application for certification identified a number of issues. These related to the scenarios, conceptual models, and values of the input parameters used in the calculations. It is expected that these issues will be addressed and resolved during the first 5-year recertification process that began with the first receipt of waste at WIPP on March 26, 1999, and scheduled to be completed in March 2004.

Geological Phenomena↗
PubMedDate not supplied

Data and information quality strategic plan.

The Environmental Protection Agency's Strategic Plan was developed in response to internal and external concerns about the integrity, consistency, and accuracy of EPA's environmental data. This document explains why a Strategic Plan is needed and the methodology used in its development, cites Agency models of excellence, and presents the six recommendations of EPA's Data and Information Quality Strategic Plan.

Database Management Systems↗
PubMed2000

Chemicals in the environment and developmental toxicity to children: a public health and policy perspective.

There are numerous pesticides and toxic chemicals in the environment that have yet to be evaluated for potential to cause developmental neurotoxicity. Recent legislation and testing initiatives provide an impetus to generating more information about potential hazards to children. In the United States, the 1996 Food Quality Protection Act (FQPA) required the U.S. Environmental Protection Agency (U.S. EPA) to make a finding that a pesticide food use is safe for children. In addition, the law requires U.S. EPA to incorporate an additional 10-fold factor in risk assessments for pesticide residue tolerances to take into account the special sensitivities of infants and children as well as incomplete data with respect to toxicity and exposures. The potential of chemicals in food and drinking water to cause endocrine disruption will also be examined via the Endocrine Disruptor Screening and Testing Program required by the FQPA and the 1996 Safe Drinking Water Act. In addition, a new voluntary chemical information program will provide screening-level information for the some 2,800 high-volume chemicals in commerce in the United States. These initiatives will need to be accompanied by research focused on developmental toxicity for children, including developmental disabilities. Developmental disabilities exact a large toll on children's health in the United States. Three major developmental disabilities--autism, cerebral palsy, and severe mental retardation--each affect substantial numbers of children. We know very little about the etiology of these conditions. A number of priority areas for research are suggested, including a large environmental prospective study of developmental neurotoxicity.

Child↗