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PubMed1990

Sources of mutagenic activity in urban fine particles.

Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model.

Air Pollutants↗
PubMed1997

Variation of 222Rn in public drinking water supplies.

The U.S. Environmental Protection Agency has proposed regulating 222Rn in public drinking water. When implemented, the regulation will require periodic sampling to demonstrate compliance. The work reported in this paper was conducted to evaluate how reliably grab samples can be used to characterize the average 222Rn concentration in a groundwater source. Periodic samples were collected from 14 wells over sampling periods ranging from 2 to 26 mo. Samples were collected using a "slow-flow" collection method, and samples were analyzed using liquid scintillation techniques. The results reveal variation in 222Rn concentration over the study period; however, for the 1,468 samples collected from the 14 wells, approximately 97% of the measurement results were within 30% of the mean value for the well.

Geological Phenomena↗
PubMedDate not supplied

Hazardous waste disposal and the clinical laboratory.

Negligent, unregulated hazardous waste management has resulted in real and potential threats to public health and safety. The federal government has responded with laws and regulations aimed at the producers of hazardous waste, including clinical laboratories. Clinical laboratory managers must understand how the requirements apply to their facilities and how to comply with them, or risk violating the law. The Resources Conservation and Recovery Act (RCRA) imposes controls on hazardous waste management through the Code of Federal Regulations (CFR). The Environmental Protection Agency (EPA) and the Department of Transportation (DOT) regulate these activities through 40 CFR and 49 CFR, respectively. 49 CFR specifies the characteristics of hazardous waste and lists more than 400 toxic chemicals, including several commonly used in clinical laboratories. Laboratories must conduct chemical inventories to determine if they should obtain an EPA identification number as a hazardous waste generator. Most clinical laboratories can operate satellite accumulation points and accumulate, store, transport, and dispose of waste in accordance with EPA and DOT regulations. Regulations pertaining to infectious waste, sure to affect many clinical laboratories, are being developed now by the EPA. The tracking system mandated by the federal government can be supplemented by state and local authorities and poses a significant regulatory challenge to clinical laboratory managers.

Facility Regulation and Control↗
PubMed1990

Methods for reducing lead exposure in young children and other risk groups: an integrated summary of a report to the U.S. Congress on childhood lead poisoning.

As part of a Congressionally mandated report on U.S. childhood lead poisoning prepared by the Federal government (U.S. Agency for Toxic Substances and Disease Registry [ATSDR]), the authors have analyzed the relative effectiveness of measures to reduce source-specific lead exposure of U.S. children. An integrated overview of this analysis is presented in this article. Two national actions, the Federally mandated phasedown of lead in gasoline by the U.S. Environmental Protection Agency and the voluntary phasedown of lead use in domestic food can production, are examples of centrally directed initiatives that have been relatively successful in limiting childhood lead exposure in the U.S. Efforts to abate lead-based paint exposure of children have largely failed. This is especially true for the nation's 21 million residential units with the highest lead content paint. Similarly, abatement of lead exposure from contaminated dusts and soils has generally been unsuccessful. Comprehensive measures to reduce lead exposure from drinking water in residences and public facilities, e.g., elementary schools, are only now being promulgated or implemented. The full extent of their effectiveness remains to be demonstrated. There are many miscellaneous but potentially severe exposure sources that are difficult to control but require attention, such as poorly glazed foodware and ethno-specific preparations.

Air Pollution↗
PubMed1993

A survey of EPA/OPP and open literature data on selected pesticide chemicals tested for mutagenicity. I. Introduction and first ten chemicals.

Parties interested in registering a pesticide chemical with the U.S. Environmental Protection Agency's (USEPA's) Office of Pesticide Programs (OPP) must submit toxicity information to support the registration. Mutagenicity data are a part of the required information that must be submitted. This information is available to the public via Freedom of Information requests to the OPP. However, it is felt that this information would be more effectively and widely disseminated if presented in a published medium. Beginning with this publication, sets of mutagenicity data on pesticide chemicals will be periodically published in the Genetic Activity Profile (GAP) format. In addition, mutagenicity data extracted from the currently available open literature is also presented to provide a more complete database and to allow comparisons between the OPP-submitted data and other publicly available information.

Animals↗
PubMed1995

Evaluation of the use of uncertainty factors in deriving RfDs for some chlorinated compounds.

Risk assessment of exposure to chemicals having a toxic endpoint routinely uses the reference dose (RfD) approach based on uncertainty factors of 10. The purpose of this investigation was to evaluate whether the magnitude of the U.S. Environmental Protection Agency (EPA) 10x uncertainty factors has scientific merit when compared with data from recent human and animal experimental studies. A compilation and comparison of ratios between LOAEL/NOAEL (lowest observed adverse effect level/no observed adverse effect level) and subchronic/chronic values was made for six chlorinated compounds, namely, carbon tetrachloride, methylene chloride, pentachlorophenol, monochlorobenzene, chlorpyrifos, and 1,1-dichloroethane. Data sets demonstrated that 91.3% of the LOAEL/NOAEL ratios were < or = 6 while 87% of the ratios for the same parameter were < or = 5. Furthermore, subchronic/chronic ratios were < or = 3.5. From our investigation we concluded that automatic safety factors of 10x are not scientifically supportable and are overly conservative for the chlorinated compounds studied here.

Animals↗
PubMedDate not supplied

Regulatory perspective of pesticide analytical enforcement methodology in the United States.

A critical overview is presented of the current regulatory problems encountered by the U.S. Environmental Protection Agency in evaluating the adequacy of pesticide analytical enforcement methodologies submitted in support of proposed pesticide tolerances. One of these problems is the development and validation of appropriate, adequate enforcement analytical methods which account for all free or bound/conjugated residue components of the "total toxic residue" in the commodities of concern. Also included is a detailed discussion of suggested improvements in the development and validation of these enforcement methods, for example, integrating radiolabeled metabolism studies with the subsequent development and validation of proposed analytical enforcement methodologies. New procedures are proposed to facilitate the availability of analytical methods to enforcement agencies and other organizations during the method validation process. Future initiatives to use the collaborative study process in the development and validation of Pesticide Analytical Manual, Volume 2, enforcement methods for contemporary pesticides are also discussed.

Legislation, Drug↗
PubMedDate not supplied

Pesticide residues in composited milk collected through the U.S. Pasteurized Milk Network.

The U.S. Food and Drug Administration (FDA) has implemented a comprehensive monitoring program to determine the incidence and levels of organohalogen pesticide residues in milk representing most of the U.S. supply consumed in metropolitan areas. Residue findings for 806 composite milks collected through the Pasteurized Milk Program by the U.S. Environmental Protection Agency (EPA) in 1990-1991 are reported. Milk was collected on a monthly basis from 63 stations selected by EPA for radionuclide monitoring. These stations provide an estimated 80% of the milk delivered to U.S. population centers. At each station, milk from selected sources had been composited to represent the milk routinely consumed in its metropolitan area. Portions of these composites were forwarded to an FDA contract laboratory for pesticide residue analysis. Pesticide residues were found in 398 (49.4%) of 806 test samples, on the basis of a 0.0005 ppm limit of detection for each residue on a whole-product basis. A total of 455 occurrences of pesticide residues were found; p,p'-DDE and dieldrin accounted for 384 (84.4%) of these occurrences. The highest level was 0.019 ppm p,p'-DDE.

Animals↗
PubMed2004

Factors considered in using birds for evaluating endocrine-disrupting chemicals.

Documented effects on fish and wildlife populations, coupled with evidence from human poisonings, epidemiology, and experimental toxicology, led to the formation of the Endocrine Disruptor Screening Program within the US Environmental Protection Agency. The main objectives of the program are to validate and implement the screens and tests that have been proposed for evaluating possible endocrine-disrupting activity of chemicals. An avian two-generation test is one of the recommended higher tier tests currently undergoing prevalidation. The advantages and disadvantages of the two species of quail considered as candidates, the northern bobwhite (Colinus virginianus) and the Japanese quail (Coturnix japonica), are described as well as the basis for final selection of the Japanese quail. Among the numerous considerations necessary for ultimately optimizing a two-generation test method using birds, the following key factors are discussed: the number of birds used in the test, when to begin exposure of the P generation, selection and exposure of the F1 generation, and endpoints.

Animals↗
PubMed2001

Testing methods for detection of Cryptosporidium spp in water samples.

A large waterborne outbreak of cryptosporidiosis in Milwaukee, Wisconsin, USA in 1993 prompted a search for ways to prevent large-scale waterborne outbreaks of protozoan parasitoses. Methods for detecting Cryptosporidium parvum play an integral role in strategies that lead to appropriate treatment of surface water, but are criticized because they produce results that are highly variable. The US Environmental Protection Agency developed a set of criteria to evaluate detection methods for protozoan parasites in water. As a consequence, the Agency has had to develop approaches to reducing uncertainty of evaluations. The variability and accuracy of various methods of producing small numbers of Cryptosporidium spp oocysts were tested. The least variable and most accurate method was used to spike seven surface water, and one tap water sample to compare 4 detection methods that had been reported in the literature. The least variable and most accurate method for spiking specified numbers of oocysts into samples was found to be flow cytometry. The most effective of the methods tested for detection in surface, tap and reagent water was solid phase cytometry.

Animals↗
PubMed1996

Comparison of gas chromatography/mass spectrometry and immunoassay techniques on concentrations of atrazine in storm runoff.

Gas chromatography/mass spectrometry (GC/MS) and enzyme-linked immunosorbent assay (ELISA) techniques were used to measure concentrations of dissolved atrazine in 149 surface-water samples. Samples were collected during May 1992-September 1993 near the mouth of the White River (Indiana) and in two small tributaries of the river. GC/MS was performed on a Hewlett-Packard 5971A with electron impact ionization and selected ion monitoring of filtered water samples extracted by C-18 solid phase extraction; ELISA was performed with a magnetic-particle-based assay with photometric analysis. ELISA results compared reasonably well to GC/MS measurements at concentrations below the Maximum Contaminant Level for drinking water set by the U.S. Environmental Protection Agency (3.0 microg/L), but a systematic negative bias was observed at higher concentrations. When higher concentration samples were diluted into the linear range of calibration, the relation improved. A slight positive bias was seen in all of the ELISA data compared to the GC/MS results, and the bias could be partially explained by correcting the ELISA data for cross reactivity with other triazine herbicides. The highest concentrations of atrazine were found during the first major runoff event after the atrazine was applied. Concentrations decreased throughout the rest of the sampling period even though large runoff events occurred during this time, indicating that most atrazine loading to surface waters in the study area occurs within a few weeks after application.

Atrazine↗
PubMed2000

Development of a single-meal fish consumption advisory for methyl mercury.

Methyl mercury (meHg) contamination of fish is the leading cause of fish consumption advisories in the United States. These advisories have focused upon repeated or chronic exposure, whereas risks during pregnancy may also exist from a single-meal exposure if the fish tissue concentration is high enough. In this study, acute exposure to meHg from a single fish meal was analyzed by using the one-compartment meHg biokinetic model to predict maternal hair concentrations. These concentrations were evaluated against the mercury hair concentration corresponding to the U.S. Environmental Protection Agency's reference dose (RfD), which is intended to protect against neurodevelopmental effects. The one-compartment model was validated against blood concentrations from three datasets in which human subjects ingested meHg in fish, either as a single meal or multiple meals. Model simulations of the single-meal scenario at different fish meHg concentrations found that concentrations of 2.0 ppm or higher can be associated with maternal hair concentrations elevated above the RfD level for days to weeks during gestation. A single-meal fish concentration cutoff of > or = 2.0 ppm is an important consideration, especially because this single high exposure event might be in addition to a baseline meHg body burden from other types of fish consumption. This type of single-meal advisory requires that fish sampling programs provide data for individual rather than composited fish, and take into account seasonal differences that may exist in fish concentrations.

Adult↗
PubMed1999

Evaluation of the EPA exposure assessment for phosphoric acid.

The philosophy of this paper is that the Environmental Protection Agency's (EPA) 1990 exposure assessment for phosphoric acid is not based on sound science and therefore does not accurately characterize the eutrophication potential of phosphoric acid releases from Toxic Release Inventory (TRI) reporting facilities. This error propagates the myth that eutrophication is triggered by the release of phosphoric acid from facilities reporting releases in the TRI. A detailed evaluation of EPA's 1990 exposure assessment for phosphoric acid reveals critical flaws in their applied methodology. Significant methodological improvements detailed in this paper fundamentally alter EPA's 1990 exposure assessment and demonstrate that, contrary to EPA's conclusion, these sources of phosphoric acid do not have the potential to trigger eutrophication in surface waters. Therefore, when sound scientific principles are applied in this comparative exposure assessment, EPA's policy maintaining phosphoric acid on the TRI list is inappropriate.

Agrochemicals↗
PubMed2004

Predicting premature mortality from new power plant development in Virginia.

The authors estimated the number of premature deaths from particulate matter less than 2.5 microm (PM2.5) that would result from making 29 proposed fossil fuel power plants in Virginia operational. We used a U.S. Environmental Protection Agency air quality model (Climatological Regional Dispersion model) to calculate changes in ambient concentrations of PM2.5 and Cox proportional hazard modeling to calculate the resulting premature mortality. The model predicted that if all 29 plants were operational, PM2.5 concentrations would rise in 271 counties across 19 states 5 and increased average annual PM2.5 concentrations would result in a rate of 17 deaths per 37,900,026 people aged 30 yr and older (0.45 deaths per million, 95% confidence interval = 0.31, 0.59) per year by the end of 2004, increasing thereafter. Over a 6 yr period, 104 cumulative excess deaths would occur due to operations of these proposed plants. The authors recommend that precautionary principles be considered when policy decisions related to energy production from fossil fuels are made.

Air Pollutants↗
PubMed2001

Probabilistic risk assessment of cotton pyrethroids: IV. Landscape-level exposure characterization.

Aquatic exposure arising from the use of pyrethroid insecticides on cotton in the United States was estimated as part of an extensive pyrethroid aquatic risk assessment. The exposure analysis was based on the standard U.S. Environmental Protection Agency tier II regulatory scenario for cotton, which assumes a 1-ha pond surrounded by 10 ha of treated crop, with high levels of runoff, erosion, and drift entering the pond. This regulatory scenario was modified to include simplified landscape-level information on the proximity of cotton to ponds derived from a remote sensing study. This scenario also accounts for the no-spray buffers between pyrethroid applications and surface waters mandated on all cotton pyrethroid labels (which differentiate applications made by air and by ground-based equipment), and for the percentage of cotton area that is treated with pyrethroids. Incorporation of these landscape-level factors into the analysis reduced the predicted aquatic exposure concentrations approximately 50- to 100-fold. Because many other conservative assumptions in the original tier II exposure analysis were not revised, the modified exposure predictions are still overestimates of true field exposure concentrations.

Animals↗
PubMedDate not supplied

U.S. Food and Drug Administration monitoring of pesticide residues in infant foods and adult foods eaten by infants/children.

The U.S. Food and Drug Administration uses 3 approaches to monitor pesticide residues in foods: regulatory monitoring, incidence/level monitoring, and the Total Diet Study. The results of monitoring infant foods and adult foods that may be eaten by infants/children under these 3 approaches are presented. Under regulatory monitoring, which is performed to enforce tolerances set by the U.S. Environmental Protection Agency (EPA), during fiscal years 1985-1991, over 10,000 such domestic and imported food samples were collected and analyzed, and under the Total Diet Study, in which pesticide residue intakes are estimated in foods prepared for consumption, the food items in 27 market baskets were analyzed. Under incidence/level monitoring, which is complementary to regulatory monitoring, over 4000 analyses were performed on infant foods and adult foods eaten by children. Fewer than 50 of the 10,000 regulatory samples had violative residues; nearly all of those were residues for which there was no tolerance for the particular commodity/pesticide combination. Under incidence/level monitoring and the Total Diet Study, the levels of pesticide residues found in infant foods and adult foods eaten by children were well below tolerances set by EPA.

Child↗
PubMed2001

Perchlorate levels in samples of sodium nitrate fertilizer derived from Chilean caliche.

Paleogeochemical deposits in northern Chile are a rich source of naturally occurring sodium nitrate (Chile saltpeter). These ores are mined to isolate NaNO3 (16-0-0) for use as fertilizer. Coincidentally, these very same deposits are a natural source of perchlorate anion (ClO4-). At sufficiently high concentrations, perchlorate interferes with iodide uptake in the thyroid gland and has been used medicinally for this purpose. In 1997, perchlorate contamination was discovered in a number of US water supplies, including Lake Mead and the Colorado River. Subsequently, the Environmental Protection Agency added this species to the Contaminant Candidate List for drinking water and will begin assessing occurrence via the Unregulated Contaminants Monitoring Rule in 2001. Effective risk assessment requires characterizing possible sources, including fertilizer. Samples were analyzed by ion chromatography and confirmed by complexation electrospray ionization mass spectrometry. Within a lot, distribution of perchlorate is nearly homogeneous, presumably due to the manufacturing process. Two different lots we analyzed differed by 15%, containing an average of either 1.5 or 1.8 mg g-1. Inadequate sample size can lead to incorrect estimations; 100-g samples gave sufficiently consistent and reproducible results. At present, information on natural attenuation, plant uptake, use/application, and dilution is too limited to evaluate the significance of these findings, and further research is needed in these areas.

Chile↗
PubMed2000

Continuous emissions monitoring using spark-induced breakdown spectroscopy.

A new technology for monitoring airborne heavy metals on aerosols and particulates based on spark-induced breakdown spectroscopy (SIBS) was evaluated at a joint U.S. Environmental Protection Agency (EPA)/U.S. Department of Energy test at the rotary kiln incinerator simulator (RKIS) facility at EPA/Research Triangle Park, NC, in September 1997. The instrument was configured to measure lead and chromium in a simulated combustion flue gas in real time and in situ at target levels of 15 and 75 micrograms/dry standard cubic meters. Actual metal concentrations were measured during the tests using EPA Reference Method (RM) 29. The SIBS technology detected both lead and chromium at the low- and high-level concentrations. Additionally, the hardware performed without failure for more than 100 hr of operation and acquired data for 100% of the RM tests. The chromium data were well correlated with concentration increases resulting from duct operations and pressure fluctuations that are known to entrain dust.

Aerosols↗