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.

SourceResearch connectionFrom yearThrough year

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

At least 1,225 records · Page 68Linked to original sources

PubMed1997

A multiyear workplace-monitoring program for refractory ceramic fibers: findings and conclusions.

Results of a monitoring program carried out by members of the Refractory Ceramic Fibers Coalition as part of a Consent Agreement with the U.S. Environmental Protection Agency to measure workplace concentrations of refractory ceramic fiber (RCF) are presented. More than 700 personal monitoring samples were collected and analyzed annually from workers in RCF production and processing plants, as well as from those employed by customers/end users. The data indicate that (i) approximately 90% of time-weighted average (TWA) workplace concentrations are below the industry's recommended exposure guideline of 1 fiber per cubic centimeter TWA; (ii) workplace concentrations vary with functional job category; (iii) concentrations are approximately lognormally distributed; (iv) workplace concentrations are generally decreasing; (v) there are significant differences in workplace concentrations among plants operated by both RCF producers and customers; (vi) equations can be developed to interconvert data analyzed using different measurement techniques and counting rules; (vii) usage of respirators varies with the functional job category of the worker and the average fiber concentration; and (viii) workplace samples differ from those used in animal inhalation experiments in terms of the ratio of respirable particles to fibers.

Ceramics↗

PubMed2001

Estimation and validation of mercury intake associated with fish consumption in an EPIC cohort of Spain.

OBJECTIVE: To estimate mercury intake due to fish consumption among the individuals from Gipuzkoa participating in the European Prospective Investigation into Cancer (EPIC), and to validate the estimation of mercury exposure through diet, by measuring blood mercury level. DESIGN AND SETTING: The population for the EPIC Gipuzkoa cohort was recruited from 1992 to 1995. Each individual's diet was assessed regarding habitual intake over the previous year, using the diet history method. Blood samples were taken at the time of the interview. The mercury content of the fish species consumed was supplied by the Food Chemical Surveillance Programme in the Basque Country. SUBJECTS: For the estimation, 8417 volunteers, men and women, aged 35-65 years, of the EPIC cohort; for the validation, a random sample of 120 individuals stratified by fish intake was taken. RESULTS: The validation study confirmed the relationship between fish consumption and mercury intake, as well as between fish consumption and mercury in erythrocytes. 99.9% of individuals have intakes below 75% of the Provisional Tolerable Weekly Intake (PTWI) of mercury established by the World Health Organization. But the limit dosage recommended by the United States Environmental Protection Agency, measured by the average risk index, would be exceeded often. CONCLUSIONS: No individual from the cohort would exceed the PTWI of mercury. Nevertheless, owing to the amount of fish consumed, certain individuals would have mercury intakes approaching the recommended limits. With a view to the future, we believe mercury in fish must continue to be monitored closely in order to assess the risks for the population.

Adult↗

PubMed2002

On-road facility to measure and characterize emissions from heavy-duty diesel vehicles.

In response to lingering concerns about the utility of dynamometer data for mobile source emissions modeling, the U.S. Environmental Protection Agency (EPA) has constructed an on-road test facility to characterize the real-world emissions of heavy-duty trucks. The facility was designed to effectively demonstrate the full range of vehicle operation and to measure the emissions produced. Since it began operation, the facility has been continuously upgraded to incorporate state-of-the-art technology. Its potential uses include collecting modal emissions data, validating dynamometer test parameters and results, and demonstrating new emission control technologies.

Air Pollutants, Occupational↗

PubMed2003

Quantitative structure-activity relationships for predicting potential ecological hazard of organic chemicals for use in regulatory risk assessments.

The use of quantitative structure-activity relationships (QSARs) for deriving the predicted no-effect concentration of discrete organic chemicals for the purposes of conducting a regulatory risk assessment in Europe and the United States is described. In the United States, under the Toxic Substances Control Act (TSCA), the TSCA Interagency Testing Committee and the U.S. Environmental Protection Agency (U.S. EPA) use SARs to estimate the hazards of existing and new chemicals. Within the Existing Substances Regulation in Europe, QSARs may be used for data evaluation, test strategy indications, and the identification and filling of data gaps. To illustrate where and when QSARs may be useful and when their use is more problematic, an example, methyl tertiary-butyl ether (MTBE), is given and the predicted and experimental data are compared. Improvements needed for new QSARs and tools for developing and using QSARs are discussed.

Animals↗

PubMed1986

Hexachlorobenzene in selected marine samples: an environmental perspective.

Hexachlorobenzene (HCB) has been designated by the US Environmental Protection Agency as a chemical of interest. Re-examination of previously analysed gas chromatograms and archived samples revealed peaks that co-eluted with the authentic HCB standard. Levels of HCB were less than 1 ng/g in all samples re-examined, and were at least three to four orders of magnitude lower than those of poly-chlorinated biphenyls, two orders of magnitude lower than those of pyrene and one to two orders of magnitude lower than levels of either phenanthrene or benzo[a]-pyrene found in the same mussel samples. Chromatograms of sea water (dissolved and particulate phases) and sediments also revealed very low levels of HCB. Because gas chromatography-mass spectrometry results indicated that levels of HCB were below the level of detection it was not possible to verify its presence. The environmental data on HCB provided by the US Mussel Watch programme demonstrate that HCB levels in mussels are minor compared with other organic compounds such as polychlorinated biphenyls and polycyclic aromatic hydrocarbons (phenanthrene, pyrene and benzo[a]pyrene). Mussels were transplanted to areas affected by industrial activity and by disposal of sewage sludge and dredged materials, and in relatively clean reference sites. Transplanted mussels were used to monitor the marine food chain, as surrogates for other biota in the same areas and as sentinel organisms to monitor localized differences in biologically available chemical compounds. The degree of environmental threat posed by HCB in the marine environment, as indicated by the US Mussel Watch data, is relatively low. It is therefore recommended that a decision be made not to pursue an expanded HCB monitoring programme in the marine environment solely to collect more HCB data.

Animals↗

PubMed2005

An ecological study of the association of environmental chemicals on breast cancer incidence in Texas.

PURPOSE: To investigate the role of environment in breast cancer development, we conducted an ecological study to examine the association of releases for selected industrial chemicals with breast cancer incidence in Texas. METHODS: During 1995--2000, 54,487 invasive breast cancer cases were reported in Texas. We identified 12 toxicants released into the environment by industry that: (1) were positively associated with breast cancer in epidemiological studies, (2) were Environmental Protection Agency (EPA) Toxics Release Inventory (TRI) chemicals designated as carcinogens or had estrogenic effects associated with breast cancer risk, and (3) had releases consistently reported to EPA TRI for multiple Texas counties during 1988--2000. We performed univariate, and multivariate analyses adjusted for race and ethnicity to examine the association of releases for these toxicants during 1988--2000 with the average annual age-adjusted breast cancer rate at the county level. RESULTS: Univariate analysis indicated that formaldehyde, methylene chloride, styrene, tetrachloroethylene, trichloroethylene, chromium, cobalt, copper, and nickel were positively associated with the breast cancer rate. Multivariate analyses indicated that styrene was positively associated with the breast cancer rate in women and men (beta=0.219, p=.004), women (beta=0.191, p=0.002), and women >or= 50 years old (beta=0.187, p=0.002). CONCLUSION: Styrene was the most important environmental toxicant positively associated with invasive breast cancer incidence in Texas, likely involving women and men of all ages. Styrene may be an important breast carcinogen due to its widespread use for food storage and preparation, and its release from building materials, tobacco smoke, and industry.

Adolescent↗

PubMed2001

New block-grafted anion exchanger for environmental water analysis by ion chromatography.

The IonPac AS14A is a recently developed stationary phase that was produced using a new block-grafting technique, which enables the preparation of high-water-content anion exchangers with excellent peak shape and good chromatographic efficiency. The performance of this column for the analysis of inorganic anions was compared to that obtained using an IonPac AS4A column, which is specified in US Environmental Protection Agency Method 300.0, in addition to another commonly used alternative: the AS14 column. The AS14A column is available in two different formats: 250x4 mm I.D. (7.0 microm diameter particle) and 150x3 mm I.D. (5.5 microm diameter particle). The IonPac AS14A (in 4 mm I.D. format) was found to provide similar performance to the AS14 column with increased peak efficiency and better pH stability and is a suitable alternative for the analysis of anions in moderate- to high-ionic-strength samples. The IonPac AS14A (in 3 mm I.D. format) provides comparable run times to the AS4A column with better overall peak selectivity and improved fluoride resolution, hence this column would be a suitable column to substitute in place of either the AS4A or AS14 columns for the analysis of inorganic anions in low- to moderate-ionic-strength environmental waters. The AS14A column used with an Atlas electrolytic suppressor provides equivalent method detection limits to those obtained when using a micromembrane suppressor but with the operational convenience of a self-regenerating suppressor.

Anion Exchange Resins↗

PubMed2001

The Iowa radon lung cancer study--phase I: Residential radon gas exposure and lung cancer.

Exposure to high concentrations of radon (222Rn) progeny produces lung cancer in both underground miners and experimentally-exposed laboratory animals. The goal of the study was to determine whether or not residential radon exposure exhibits a statistically significant association with lung cancer in a state with high residential radon concentrations. A population-based, case-control epidemiologic study was conducted examining the relationship between residential radon gas exposure and lung cancer in Iowa females who occupied their current home for at least 20 years. The study included 413 incident lung cancer cases and 614 age-frequency-matched controls. Participant information was obtained by a mailed-out questionnaire with face-to-face follow-up. Radon dosimetry assessment consisted of five components: (1) on-site residential assessment survey; (2) on-site radon measurements; (3) regional outdoor radon measurements; (4) assessment of subjects' exposure when in another building; and (5) linkage of historic subject mobility with residential, outdoor, and other building radon concentrations. Histologic review was performed for 96% of the cases. Approximately 60% of the basement radon concentrations and 30% of the first floor radon concentrations of study participants' homes exceeded the US Environmental Protection Agency action level of 150 Bq m(-3) (4 pCi l(-1)). Large areas of western Iowa had outdoor radon concentrations comparable to the national average indoor value of 55 Bq m(-3) (1.5 pCi l(-1)). Excess odds of 0.24 (95% CI = -0.05-0.92) and 0.49 (95% CI = 0.03-1.84) per 11 WLM(5-19) were calculated using the continuous radon exposure estimates for all cases and live cases, respectively. Slightly higher excess odds of 0.50 (95% CI = 0.004-1.80) and 0.83 (CI = 0.11-3.34) per 11 WLM(5-19) were noted for the categorical radon exposure estimates for all cases and the live cases. A positive association between cumulative radon gas exposure and lung cancer was demonstrated using both categorical and continuous analyses. The risk estimates obtained in this study indicate that cumulative radon exposure presents an important environmental health hazard.

Adult↗

PubMed2002

Environmental pollutants and disease in American children: estimates of morbidity, mortality, and costs for lead poisoning, asthma, cancer, and developmental disabilities.

In this study, we aimed to estimate the contribution of environmental pollutants to the incidence, prevalence, mortality, and costs of pediatric disease in American children. We examined four categories of illness: lead poisoning, asthma, cancer, and neurobehavioral disorders. To estimate the proportion of each attributable to toxins in the environment, we used an environmentally attributable fraction (EAF) model. EAFs for lead poisoning, asthma, and cancer were developed by panels of experts through a Delphi process, whereas that for neurobehavioral disorders was based on data from the National Academy of Sciences. We define environmental pollutants as toxic chemicals of human origin in air, food, water, and communities. To develop estimates of costs, we relied on data from the U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, National Center for Health Statistics, the Bureau of Labor Statistics, the Health Care Financing Agency, and the Practice Management Information Corporation. EAFs were judged to be 100% for lead poisoning, 30% for asthma (range, 10-35%), 5% for cancer (range, 2-10%), and 10% for neurobehavioral disorders (range, 5-20%). Total annual costs are estimated to be $54.9 billion (range $48.8-64.8 billion): $43.4 billion for lead poisoning, $2.0 billion for asthma, $0.3 billion for childhood cancer, and $9.2 billion for neurobehavioral disorders. This sum amounts to 2.8 percent of total U.S. health care costs. This estimate is likely low because it considers only four categories of illness, incorporates conservative assumptions, ignores costs of pain and suffering, and does not include late complications for which etiologic associations are poorly quantified. The costs of pediatric environmental disease are high, in contrast with the limited resources directed to research, tracking, and prevention.

Asthma↗

PubMed2003

Worker and Environmental Protection Issues in the Remediation Of an Abandoned Source Manufacturing Facility.

The Gulf Nuclear Superfund Site located in Odessa, Texas, was an abandoned radioactive source production facility slated for cleanup as a Removal Action under the U.S. Environmental Protection Agency Region VI Superfund program. Prior to cessation of operations and abandonment of the facility in 1992, it was used for the production of radioactive sources used in the oil and gas industry and nuclear medicine applications. Pangea Group was contracted by the U.S. Army Corps of Engineers (USACE) Kansas City District to perform remediation of the site and other contaminated debris, cleaning of interior building surfaces, building demolition, and excavation/removal of contaminated soils and septic system. The project scope also included loading, containerization and transportation of low-level radioactive wastes for offsite disposal. Primary radionuclides present at the facility were Cs, Co, and Am. The project also included packaging and removal of radioactive sources and mixed waste consisting of radiologically contaminated lead shot and lead source containers. Included in the paper is a discussion of primary worker protection and environmental protection measures employed on the project. Worker protection issues included the control of industrial and construction safety hazards as well as control of external and internal radiation dose. Control of air emissions and contaminated wastewater were also very important, especially due to the location of the site. The site was located in an area containing both residential and commercial properties. Several residences and businesses were located immediately adjacent to the site. The project involved the participation of the USACE Kansas City District, EPA Region 6, and the Texas Bureau of Radiological Health. Field work on the project started in April 2001 and was completed approximately five months later.

Journal Article↗

PubMed2004

Antimony: an unlikely confounder in the relationship between well water arsenic and health outcomes in Bangladesh.

Recent in vitro studies have suggested a potential role for antimony as a confounder in human health studies related to arsenic in drinking water. We measured tube-well water concentrations of antimony and arsenic in the Pabna region of Bangladesh, where arsenic concentrations are known to be elevated and the concentrations of antimony have not yet been thoroughly documented. Two hundred forty-five tube-well water samples were collected from various regions in Pabna, Bangladesh, as part of an ongoing case-control study. Water samples were analyzed for arsenic and antimony concentrations by inductively coupled plasma-mass spectrometry using U.S. Environmental Protection Agency method 200.8. The arsenic concentrations in the tube-well water samples ranged from < 1 microg/L to 747 microg/L. All 245 water samples had antimony concentrations < 1 microg/L. Based on consideration of the concentrations used the in vitro studies compared with field-observed concentrations, our results do not support the hypothesis that antimony would be a significant confounder in observed relationships between arsenic exposure through drinking water and potential health outcomes in Pabna, Bangladesh.

Antimony↗

PubMedDate not supplied

Environmentally healthy homes and communities. Children's special vulnerabilities.

We like to think that our homes are a safe haven. However, in recent years we have been discovering that certain products, designs, and even the siting of our homes can create health risks. When families moved into a new development in Waynesville, NC, called "Barber Orchard," they were ecstatic about their new surroundings--the fresh air, mountain views, and clean water. When one of the new residents had his well water tested, their dream homes took on a different character. The water was reflective of the years of pesticide use on the former orchard on which their homes were sited; it contained DDT, DDE, and benzene hydrochlorides (Manual, 2000). The soil was contaminated with lead and arsenic, also the result of pesticide applications. The Environmental Protection Agency (EPA) sent in an emergency response team, removed toposil, and advised residents to install carbon filters on their water systems. Sometimes, we unintentionally bring pollution into our homes. In the homes of middle-income families with small children, vacuum dust was found to have pesticide concentrations 10-100 times greater than those found in the surface soils surrounding their houses (Lewis et al, 1994). In the agricultural area of Washington State, 47 of 48 farm homes had chlorpyrifos (an organophosphate pesticide) measured in the house dust. The human health risks associated with chlorpyrifos are substantial (including headaches, dizziness, muscle twitching, vomiting, and blurred vision); hence, in 2000, the EPA eliminated the widely used pesticide for nearly all-household purposes. The purpose of this independent study module (ISM) is to introduce the reader to basic concepts and issues associated with environmental health risks to children in homes and communities. In this ISM, some of the key hazardous exposures occurring in the home will be discussed. Indoor air quality, drinking water, lead, mercury, pesticides, radon, and UV radiation have been selected as topics of focus. A resource section provides a brief listing of resources; many of them are Web sites, which, in turn will link the reader to additional resources. The EPA's Web site is particularly helpful. The University of Maryland School of Nursing has a new Web site, http://enviRN.umaryland.edu, with links to all of the Web sites noted in this ISM.

Air Pollution, Indoor↗

PubMed2006

Does dioxin exert toxic effects in humans at or near current background body levels?: An evidence-based conclusion.

Evidence-based toxicology like evidence-based medicine, provides scientifically grounded evidence-based conclusions as distinguished from authority-based opinions. As an example, we address a proposition from the US Environmental Protection Agency's (EPA) Draft Dioxin [2,3, 7,8-tetrachlorodibenzo-P-dioxin (TCDD)] reassessment that: 'dioxin...can produce effects...at or near current background body burdens or intake levels'. Guided by a systematic, objective, and unbiased analysis of the available molecular, physiological, and clinical/epidemiologic data, in accordance with accepted principles of scientific logic, we reach the evidence-based conclusion that the proposition is rejected. When gaps in scientific knowledge necessitate formulation of opinions to meet preventive or precautionary goals, the reversion to authority should be explicitly acknowledged.

Body Burden↗

PubMed2000

Perchlorate uptake by salt cedar (Tamarix ramosissima) in the Las Vegas wash riparian ecosystem.

Perchlorate ion (ClO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las Vegas Wash. Perchlorate is an oxidant, but its reduction is kinetically hindered. Concern over thyroid effects caused the Environmental Protection Agency (EPA) to add perchlorate to the drinking water Contaminant Candidate List (CCL). Beginning in 2001, utilities will look for perchlorate under the Unregulated Contaminants Monitoring Rule (UCMR). In wood samples acquired from the same plant growing in a contaminated stream, perchlorate concentrations were found as follows: 5-6 microg g(-1) in dry twigs extending above the water and 300 microg g(-1) in stalks immersed in the stream. Perchlorate was leached from samples of wood, and the resulting solutions were analyzed by ion chromatography after clean-up. The identification was confirmed by electrospray ionization mass spectrometry after complexation of perchlorate with decyltrimethylammonium cation. Because salt cedar is regarded as an invasive species, there are large scale programs aimed at eliminating it. However, this work suggests that salt cedar might play a role in the ecological distribution of perchlorate as an environmental contaminant. Consequently, a thorough investigation of the fate and transport of perchlorate in tamarisks is required to assess the effects that eradication might have on perchlorate-tainted riparian ecosystems, such as the Las Vegas Wash. This is especially important since water from the wash enters Lake Mead and the Colorado River and has the potential to affect the potable water source of tens of millions of people as well as irrigation water used on a variety of crops, including much of the lettuce produced in the USA.

Chromatography, Ion Exchange↗

PubMed2003

Determination of methyl mercury in dental-unit wastewater.

OBJECTIVE: The objective of this investigation was to establish whether monomethyl mercury (MMHg) is present in dental-unit wastewater and if present, to determine the concentration relative to total mercury. METHODS: Wastewater samples were collected over an 18-month period from three locations: at the dental chair; at a 30-chair clinic, and at a 107-chair clinic. Total mercury determinations were completed using United States Environmental Protection Agency's (USEPA) method 1631. MMHg was measured utilizing modified USEPA method 1630. RESULTS: The total mercury levels were found to be: 45182.11 microg/l (n=13, SD=68562.42) for the chair-side samples, 5350.74 microg/l (n=12, SD=2672.94) for samples at the 30-chair clinic, and 13439.13 microg/l (n=13, SD=9898.91) for samples at the107-chair clinic. Monomethyl Hg levels averaged 0.90 microg/l (n=13, SD=0.87) for chair side samples, 8.26 (n=12, SD=7.74) for the 30-chair facility, and 26.77 microg/l (n=13, SD=34.50) for 107-chair facility. By way of comparison, the MMHg levels for the open ocean, lakes and rain are orders of magnitude lower than methyl mercury levels seen in dental wastewater (part per billion levels for dental wastewater samples compared to part per trillion levels for samples from the environment). SIGNIFICANCE: Environmentally important levels of MMHg were found to be present in dental-unit wastewater at concentrations orders of magnitude higher than seen in natural settings.

Dental Waste↗

PubMed2006

Workshop overview: reassessment of the cancer risk of dichloromethane in humans.

The U.S. Environmental Protection Agency (U.S. EPA) classifies dichloromethane (DCM) as a "probable human carcinogen," based upon its risk assessment conducted in the late 1980s (http://www.epa.gov/iris/subst/0070.htm). Since that time, cancer risk-assessment practices have evolved, leading to improved scientifically based methods for estimating risk and for illuminating as well as reducing residual uncertainties. A new physiologically based pharmacokinetic (PBPK) model has been developed, using data from human volunteers exposed to low DCM levels, that provides new information on the human to human variability in DCM metabolism and elimination (L. M. Sweeney et al., 2004, Toxicol. Lett. 154, 201-216). This information, along with data from other published human studies, has been used to develop a new cancer risk estimation model utilizing probabilistic methodology similar to that employed recently by U.S. EPA for other chemicals (ENVIRON Health Sciences Institute, 2005, Development of population cancer risk estimates for environmental exposure to dichloromethane using a physiologically based pharmacokinetic model. Final Report to Eastman Kodak Company). This article summarizes the deliberations of a scientific peer-review panel convened on 3 and 4 May 2005 at the CIIT Centers for Health Research in Research Triangle Park, North Carolina, to review the "state of the science" for DCM and to critically evaluate the new information for its utility in assessing potential human cancer risks from DCM exposure. The panel (Melvin E Andersen, CIIT Centers for Health Research, Research Triangle Park, NC 27709; A. John Bailer, Miami University, Scripps Gerontology Center, Oxford, OH 45056; Kenneth S. Crump, ENVIRON Health Sciences Institute, Ruston, LA 71270; Clifford R. Elcombe, University of Dundee, Biomedical Research Centre, Dundee DD1 9SY, United Kingdom; Linda S. Erdreich, Exponent, 420 Lexington Avenue, Suite 1740, New York, NY 10170; Jeffery W. Fisher, University of Georgia, Department of Environmental Health Science, Athens, GA 30602; David Gaylor, Gaylor and Associates, LLC, Eureka Springs, AR 72631; F Peter Guengerich, Vanderbilt University, Department of Biochemistry, Nashville, TN 37232; Kenneth Mundt, ENVIRON Health Sciences Institute, Amherst, MA 01004; Lorenz R Rhomberg, Gradient Corporation, Cambridge, MA 021138; Charles Timchalk, Pacific Northwest National Laboratory, Richland, WA 99352), chaired by M.E.A., was composed of experts in xenobiotic metabolism and carcinogenic mechanisms, PBPK modeling, epidemiology, biostatistics, and quantitative risk assessment. Observers included representatives from U.S. EPA, CIIT, and Eastman Kodak Company (Kodak), as well as several consultants to Kodak. The workshop was organized and sponsored by Kodak, which employs DCM as a solvent in the production of imaging materials. Overall, the panel concluded that the new models for DCM risk assessment were scientifically and technically sound and represented an advance over those employed in past assessments.

Carcinogens↗

PubMedDate not supplied

Assessment of potential health risks associated with ingesting heavy metals in fish collected from a hazardous-waste contaminated wetland in Louisiana, USA.

Significant adverse effects on environmental quality, ecosystem integrity, and human health have often been associated with improper disposal of hazardous materials. This study ascertains the levels of eight heavy metals in various fish species that were collected from a local hazardous-waste-contaminated wet-land and estimates the potential health risk that may be associated with consuming such fish. We examined a total of 53 fish samples representing 12 different species. The respective mean concentrations (ng/g) of arsenic, cadmium, chromium, copper, iron, lead, mercury, and nickel found in edible tissues were as follows: 72.5 +/- 103.1, 55.4 +/- 34.6, 97.4 +/- 111.7, 177.3 +/- 328.3, 2711.0 +/- 4469.6, 26.0 +/- 119.0, 32.7 +/- 75.3, and 81.5 +/- 178.9. For a 10-kg child eating 6.5 g of fish per day, the computed combined hazard index was 0.475 ; for 70-kg adults with a daily consumption of 6.5 g (general population), 30 g (sport fishermen), and 140 g (subsistence fishermen), the respective computed hazard indices were 0.068, 0.313, and 1.462. The results indicate that subsistence fishermen had the highest risk for systemic effects, with an exposure exceeding the Environmental Protection Agency (EPA) Reference Dose value. In a 10-kg child, such excess exposure would be reached--even with such single metals as arsenic and mercury--when applying the EPA-approved maximum fish consumption rate of 54 g/day to the general population. The cancer risk for arsenic, the only metal with an established cancer potency factor from oral exposure, varied from 8 x 10(-6) to 253 x 10(-6), indicating an exposure exceeding the widely accepted risk level of 1 x 10(-6) (one excess cancer per 10(6) population).

Adult↗

PubMed2003

Assessment of the mutagenic potency of sewage sludges contaminated with polycyclic aromatic hydrocarbons by an Ames sludges for fluctuation assay.

The mutagenicity of crude extracts and subfractions of two samples of a reference sewage sludge material and two sewage sludges from two wastewater treatment plants (WWTP), one urban and the other one urban mixed with industrial, was assessed using an Ames fluctuation assay based on 384-well microtiter plates with liquid cultures. Crude extracts of sludges were obtained by ultrasonic extraction with dichloromethane/methanol, and further column fractionation yielded two fractions, one of which containing mutagenic polycyclic aromatic hydrocarbons (PAHs). Quantitative analysis performed by gas chromatography-mass spectrometry gave sum concentrations of the 16 PAHs listed as priority pollutants by the U.S. Environmental Protection Agency at levels between 1,305 and 2,442 microg/kg. Subjecting crude extracts and column fractions to the mutagenicity assay with Salmonella strains TA98 and TA 100 provided good qualitative correlation between the presence of mutagenic PAH and the induction of gene mutations. In general, the crude extracts and the PAH-fractions induced positive responses in the assay with both bacterial strains on metabolic activation by S9 rat-liver homogenate, whereas direct-acting mutagens were not detectable. In the assay with the real sludge samples of two different WWTPs, TA98 proved to be more sensitive than TA100; however, similar sensitivities of the tester strains were observed for two reference sewage sludge materials of the same origin. The outcomes of the Ames fluctuation assay demonstrated its performance as a cost-effective and relatively rapid screening tool to assess the genotoxic potential of complex environmental samples.

Animals↗