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PubMed1990

Modelling of environmental lead contributors to blood lead in human.

The Second National Health and Nutrition Examination Survey (NHANES II) is the only representative national study of body burden of lead where detailed concurrent information is available on a number of geographic and socio-economic factors. To date, however, reliable information on concurrent local environmental lead exposure for the sample has been lacking. In this study, we have identified and utilized previously unused concurrent lead exposure data. Our exposure data include time and region specific information on sales of lead from gasoline and ambient air-lead measurements from the United States Environmental Protection Agency (EPA). In addition, we have included information on lead consumed in food from the United States Food and Drug Administration (FDA). Our results indicate weak but significant associations between state sales of lead from gasoline and blood lead. In addition, we found a significant association between ambient air lead measurements and blood-lead concentrations. Socio-economic factors and life-style factors were significantly related to blood lead, controlling for other possible confounders. Overall, our model explained 34% of the variance in blood-lead levels, which is a significant improvement compared to the maximum of 25% from other studies using the NHANES II data. The study substantiates prior findings that the majority of the variance in overall blood lead is significantly related to lead sources other than gasoline. From a public health perspective, it is therefore imperative that lead screening programs be continued and focused on multiple sources of lead, including lead in gasoline. The study supports prior findings of a continuous decrease in blood lead, independent of decreases of lead from gasoline.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2006

A comparison of bacterial indicators and methods in rural surface waters.

The United States Environmental Protection Agency (USEPA) recommends the use of Escherichia coli (E. coli) and enterococci as indicators of enteric pathogens in fresh waters; however, fecal coliform analyses will remain important by virtue of the large amount of historic data collected in prior years. In this study, we attempted, in a real-world situation (i.e., a rural inland watershed in the Piedmont of South Carolina) to compare different bacterial indicators and methods to one another. We compared fecal coliforms, enumerated by membrane filtration with E. coli, enumerated by a commercialized enzyme substrate method and observed E. coli/fecal coliform ratios of 1.63 and 1.2 for two separate tests. In the same watershed, we observed an E. coli/fecal coliform ratio of 0.84 when we used the commercialized enzyme substrate method for both enumerations. Given these results, users of such data should exercise care when they make comparisons between historic membrane filtration data and data acquired through the use of the more modern enzymatic methods. Some sampling and side-by-side testing between methods in a specific watershed may be prudent before any conversion factors between old and new datasets are applied.

Colony Count, Microbial↗
PubMed2004

Photochemical smog modeling for assessment of potential impacts of different management strategies on air quality of the Bangkok Metropolitan Region, Thailand.

A photochemical smog model system, the Variable-Grid Urban Airshed Model/Systems Applications International Mesoscale Model (UAM-V/SAIMM), was used to investigate photochemical pollution in the Bangkok Metropolitan Region (BMR). The model system was first applied to simulate a historical photochemical smog episode of two days (January 13-14, 1997) using the 1997 anthropogenic emission database available at the Pollution Control Department and an estimated biogenic emission. The output 1-hr ozone (O3) for BMR, however, did not meet the U.S. Environmental Protection Agency suggested performance criteria. The simulated minimum and maximum O3 values in the domain were much higher than the observations. Multiple model runs with different precursor emission reduction scenarios showed that the best model performance with the simulated 1-hr O3 meeting all the criteria was obtained when the volatile organic compound (VOC) and oxides of nitrogen (NOx) emission from mobile source reduced by 50% and carbon monoxide by 20% from the original database. Various combinations of anthropogenic and biogenic emissions in Bangkok and surrounding provinces were simulated to assess the contribution of different sources to O3 pollution in the city. O3 formation in Bangkok was found to be more VOC-sensitive than NOx-sensitive. To attain the Thailand ambient air quality standard for 1-hr O3 of 100 ppb, VOC emission in BMR should be reduced by 50-60%. Management strategies considered in the scenario study consist of Stage I, Stage II vapor control, replacement of two-stroke by four-stroke motorcycles, 100% compressed natural gas bus, 100% natural gas-fired power plants, and replacement of methyltertiarybutylether by ethanol as an additive for gasoline.

Air Pollutants↗
PubMed2003

Significant issues raised by meta-analyses of cancer mortality and dioxin exposure.

Consistent with results from an earlier U.S. Environmental Protection Agency meta-analysis of three occupational cohorts, Crump et al. [Environ Health Perspect 111:681-687 (2003)] recently concluded that "dioxin TEQ [toxic equivalent] exposures within roughly 3-fold of current background levels may be carcinogenic" to humans. In contrast, my meta-analysis using an intercept-only model implied zero additional human cancer deaths from all exposures to dioxin-like compounds, including those arising via dietary intake. How can different investigators reach such markedly different conclusions from similar analyses of essentially the same data? The answer lies in different selections for a dose metric, different assumptions regarding the elimination half-life for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in humans, different assumptions regarding the importance of the most recent 15 years of exposure, and extrapolations from potential effects of TCDD exposure to potential effects of TEQ exposures. Resolution of the ongoing debate regarding the potential human carcinogenicity of dioxin will require detailed information on exposure to TCDD and on direct-acting carcinogens in the workplace, as well as a dose-response model that adequately reflects TCDD's characteristics as a promoter.

Cohort Studies↗
PubMed2005

In-vessel composting--bioremediation of aged coal tar soil: effect of temperature and soil/green waste amendment ratio.

The biodegradation of 16 United States Environmental Protection Agency (USEPA)-listed polycyclic aromatic hydrocarbons (PAHs) present in contaminated soil from a manufactured gas plant site was investigated using laboratory-scale in-vessel composting-bioremediation reactors over 8 weeks. The influence of temperature (T, 38, 55, and 70 degrees C) and soil/green waste ratio (S:GW, 0.6:1, 0.7:1, 0.8:1, and 0.9:1) was investigated. A comparative study using a temperature profile during in-vessel composting-bioremediation to meet current regulatory requirements was also investigated. Temperature and amendment ratio were found to be important operating parameters for PAH removal for in-vessel composting-bioremediation of aged coal tar-contaminated soil. After 8 weeks of continuous treatment, the highest removal of 16 USEPA PAHs was observed at T=38 degrees C and S:GW=0.8:1 (75.2%). Lower removal of 16 USEPA PAHs was observed for temperature profile treatment (60.8%). We recommend that when conventional composting processes using temperature profiles to meet regulatory requirements for pathogen control need to be used, these should start with a prolonged mesophilic stage (6 weeks in this investigation) followed by thermophilic, cooling, and maturation stages.

Biodegradation, Environmental↗
PubMed2001

Determination of the aquatic PNEC0.05 for boron.

Several weight of the evidence approaches for the effects assessment of boron to aquatic organisms have been conducted. The focal point for all of these assessments is the appropriate interpretation of the LC1 for rainbow trout (Oncorhynchus mykiss) from W.J. Birge, J.A. Black, Report No. EPA5601176408. Environmental Protection Agency, Office of Toxic Substances, Washington, DC, 1977, as the LC1 from their studies provided the lowest chronic toxicity values for boron. Other studies by these investigators (W.J. Birge, J.A. Black, Completion Report prepared for the Procter & Gamble Company, Cincinnati, USA, 1981; W.J. Birge, J.A. Black, A.G. Westermann, T.M. Short, S.B. Taylor, M.C. Parekh. Completion Report prepared for the Procter & Gamble Company, Cincinnati, USA, 1984; J.A. Black, J.B. Barnum, W.J. Birge, Chemosphere 26 (1993) 1383-1413) further indicate this species to be particularly sensitive to boron. While weight of the evidence approaches have been necessary for diverse risk assessment needs, they each suffer from potential bias via professional judgment. In order to allay these issues and to update the effects assessment for boron, a probabilistic approach was used. Raw data from the Birge and Black studies were reanalyzed to generate chronic values representative of the adverse effects threshold (e.g., LC10) for several species. A comprehensive list of chronic data from these studies and other studies were combined into a cumulative probability term, allowing for the determination of the fifth percentile protection value, or PNEC0.05. The PNEC0.05 for boron was determined to be at least 1.3 mg B/l.

Animals↗
PubMedDate not supplied

Personal exposure to airborne particles and metals: results from the Particle TEAM study in Riverside, California.

The PTEAM Study was the first large-scale probability-based study of personal exposure to particles. Sponsored by the U.S. Environmental Protection Agency (EPA) and the Air Resources Board of California, it was carried out by the Research Triangle Institute (RTI) and the Harvard University School of Public Health (HSPH). HSPH designed and constructed a 4-lpm, battery-operated personal monitor for inhalable particles (PM10) that could be worn comfortably for up to 14 hours by persons from 10 to 70 years old. The monitor was worn for two consecutive 12-hour periods (day and night) during the fall of 1990 by 178 participants representing 139,000 nonsmoking residents of Riverside, California. Nearly identical monitors were employed to collect concurrent indoor and outdoor samples. The monitors were equipped with a different sampling nozzle to collect fine particles (PM2.5). Population-weighted daytime personal PM10 exposures averaged 150 +/- 9 (SE) micrograms/m3, compared to concurrent indoor and outdoor concentrations of 95 +/- 6 micrograms/m3. This suggested the existence of excess mass near the person, a "personal cloud" that appeared related to personal activities. Fourteen of 15 prevalent elements also were evaluated in the personal samples. The two major indoor sources of indoor particles were smoking and cooking; even in these homes, however, more than half of the indoor particles came from outdoors, and a substantial portion of the indoor particles were of undetermined indoor origin. Outdoor concentrations near the homes were well correlated with outdoor concentrations at the central site, supporting the idea of using the central site as an indicator of of ambient concentrations over a wider area. Indoor concentrations were only weakly correlated with outdoor concentrations, however, and personal exposures were even more poorly correlated with outdoor concentrations. Elemental profiles were obtained for environmental tobacco smoke (ETS) (major contributions from potassium and chlorine) and cooking emissions (aluminum, iron, calcium, and chlorine). These profiles can be used in future source apportionment studies.

Adolescent↗
PubMed2001

Dredged material decontamination demonstration for the port of New York/New Jersey.

Management of contaminated dredged material is a significant challenge in the Port of New York and New Jersey as a result of more stringent regional ocean placement regulations with escalating costs for upland placement. One component of an overall management plan can be the application of a decontamination technology followed by creation of a product suitable for beneficial use. This concept is the focus of a project now being carried out by the US Environmental Protection Agency, Region 2, the US Army Corps of Engineers, New York District, the US Department of Energy, Brookhaven National Laboratory, and regional university groups that have included Rensselaer Polytechnic Institute, Rutgers University, New Jersey Institute of Technology, and Stevens Institute of Technology. The project has progressed through phased testing of commercial technologies at the bench scale (15 liters) (Marcor, Metcalf & Eddy, Gas Technology Institute, Westinghouse Science & Technology, BioGenesis, International Technology, and BioSafe) and pilot-scale (1.5-500m(3)) (BioGenesis, Gas Technology Institute, and Westinghouse Science & Technology) levels. The technologies developed by Gas Technology Institute and BioGenesis are now going forward to commercial demonstration facilities that are intended to treat from 23000 to 60000m(3) of dredged material during their first operational period in 2001-2002. Beneficial use products are soils and cement. Treatment costs for the final commercial facilities are estimated at US$ 39 per m(3). Selection of the technologies was made based on the effectiveness of the treatment process, evaluation of the possible beneficial use of the treated materials, and other factors. Major elements of the project are summarized here.

Conservation of Natural Resources↗
PubMed2006

Contaminated sediment testing with the bivalve Mulinia lateralis: culture refinement for organism availability.

Availability of test species for estuarine benthic assessment is limited; therefore, a method was developed by the U.S. Environmental Protection Agency for using the dwarf surf clam (Mulinia lateralis) to identify adverse biological effects of bulk estuarine sediments. A multilaboratory evaluation of the draft method resulted in favorable responses from the participants with respect to general testing and handling of the clam. However, availability of good-quality test organisms was limited. An investigation of culture techniques determined that culture vessel topography dramatically influenced survival, because larvae accumulated in bottom depressions. Conditioning of brood stock was enhanced by algae naturally containing both 20:5n-3 and 22:6n-3 fatty acids. Survival of larvae to metamorphosis at 14 d postspawn was greatly increased by maintenance at a lighting of 734 lux with addition of gradually increasing amounts of Isochyris galbana and Chaetoceros calcitrans. Greater than 50% survival of 600 juveniles to testing size by 14 d postmetamorphosis was accomplished by intermittent delivery of algae 12 times per day in a total of 13 L of seawater. By 21 d postmetamorphosis, an additional 27% achieved testable size. As a result of identification of these culture parameters, test bivalves can be readily available to improve predictions of adverse biological effects on benthic communities beyond those presently determined through amphipod exposures.

Animals↗
PubMed1983

Selected pesticide residues or metabolites in blood and urine specimens from a general population survey.

The National Center for Health Statistics collaborated with the National Human Monitoring Program of the U.S. Environmental Protection Agency (EPA) in a four-year study to assess the exposure of the general population to selected pesticides through analysis of blood serum and urine specimens. Specimens were collected on a national probability half sample of persons 12-74 years of age from 64 locations across the United States comprising the sample areas in the Second Health and Nutrition Examination Survey (NHANES II) and analyzed for selected organochlorine, carbamate, chlorophenoxy and organophosphorus pesticides. Medical, nutritional and pesticide usage data are also available for each sample person. Preliminary results of the blood serum and urine analyses indicate that the general population is being exposed to some of these types of pesticides. Since 1970, EPA has conducted a national probability sampling of human adipose tissue. Specimens obtained on a survey design representative of the general population were analyzed for selected organochlorine pesticides and toxic chemicals. Findings from the 1978 survey also indicate exposure of the general population to some of these chemicals. Medical data collected from both surveys have yielded no overt correlations between health effects and residue levels. More intensive statistical analyses are underway to investigate the possible existence of more subtle relationships.

Adolescent↗
PubMed2006

Correlation of in vitro cytokine responses with the chemical composition of soil-derived particulate matter.

We treated human lung epithelial cells, type BEAS-2B, with 10-80 microg/cm2 of dust from soils and road surfaces in the western United States that contained particulate matter (PM) < 2.5 microm aerodynamic diameter. Cell viability and cytokine secretion responses were measured at 24 hr. Each dust sample is a complex mixture containing particles from different minerals mixed with biogenic and anthropogenic materials. We determined the particle chemical composition using methods based on the U.S. Environmental Protection Agency Speciation Trends Network (STN) and the National Park Service Interagency Monitoring of Protected Visual Environments (IMPROVE) network. The functionally defined carbon fractions reported by the ambient monitoring networks have not been widely used for toxicology studies. The soil-derived PM2.5 from different sites showed a wide range of potency for inducing the release of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in vitro. Univariate regression and multivariate redundancy analysis were used to test for correlation of viability and cytokine release with the concentrations of 40 elements, 7 ions, and 8 carbon fractions. The particles showed positive correlation between IL-6 release and the elemental and pyrolyzable carbon fractions, and the strongest correlation involving crustal elements was between IL-6 release and the aluminum:silicon ratio. The observed correlations between low-volatility organic components of soil- and road-derived dusts and the cytokine release by BEAS-2B cells are relevant for investigation of mechanisms linking specific air pollution particle types with the initiating events leading to airway inflammation in sensitive populations.

Air Pollutants↗
PubMed1999

A computer program for conducting incinerator risk assessments.

In 1994, the United States Environmental Protection Agency (USEPA) developed a screening methodology for conducting indirect exposure risk assessments for combustion facilities. The United States Army Center for Health Promotion and Preventive Medicine currently utilizes this methodology in conjunction with other USEPA guidance documents to perform human health risk assessments (HHRAs). The HHRAs require the development of complex human health models using spreadsheet software packages which estimate various media concentrations of contaminants in the environment. Since the quality assurance/quality control procedures associated with verifying the model's results are extremely time consuming, a computer program was developed using Microsoft Excel to minimize the amount of time needed. This discussion describes the 6 steps taken in developing this computer program, which are: (1) understanding the problem; (2) establishing the structure of each table in the spreadsheets; (3) developing an algorithm to solve the problem; (4) writing code; (5) running the program; and (6) testing the results. The automated process of having the computer predict health risk and hazards for each potentially exposed individual saves a tremendous amount of time because each calculated value is placed in the correct spreadsheet cell location. In addition to the time needed to develop human health spreadsheets, this program also minimizes the potential for reducing human error.

Algorithms↗
PubMed2002

Development and evaluation of the Lake Macroinvertebrate Integrity Index (LMII) for New Jersey lakes and reservoirs.

In response to the recent focus by the U.S. Environmental Protection Agency on bioassessment of lakes, a multimetric index was developed for New Jersey lakes and reservoirs using benthic macroinvertebrates. Benthic samples were collected from reference and impaired lakes with muck and intermediate sediments in central and northern New Jersey during summer 1997. We used a stepwise process to evaluate properties of candidate metrics and selected five for the Lake Macroinvertebrate Integrity Index (LMII): Hilsenhoff Biotic Index (HBI), percent chironomid individuals, percent collector-gatherer taxa, percent oligochaetes/leeches, and number of Diptera taxa. We scored metrics as the fraction of the best expected value (based on all sites) achieved at a site and summed them into the LMII. Evaluation of the LMII showed that it discriminated well between reference and impaired lakes and was strongly related to several potential stressors. Chemical and physical gradients distinguished between reference and impaired lakes, and the LMII summarized these gradients well. The LMII corresponded strongly with land use, but some lakes with more urban land use still achieved high scores. Based on a power analysis, the ability of the LMII to detect differences in condition was sensitive to the number of samples from each lake.

Animals↗
PubMed2003

Childhood cancer incidence rates and hazardous air pollutants in California: an exploratory analysis.

Hazardous air pollutants (HAPs) are compounds shown to cause cancer or other adverse health effects. We analyzed population-based childhood cancer incidence rates in California (USA) from 1988 to 1994, by HAP exposure scores, for all California census tracts. For each census tract, we calculated exposure scores by combining cancer potency factors with outdoor HAP concentrations modeled by the U.S. Environmental Protection Agency. We evaluated the relationship between childhood cancer rates and exposure scores for 25 potentially carcinogenic HAPs emitted from mobile, area, and point sources and from all sources combined. Our study period saw 7,143 newly diagnosed cancer cases in California; of these, 6,989 (97.8%) could be assigned to census tracts and included in our analysis. Using Poisson regression, we estimated rate ratios (RRs) adjusted for age, race/ethnicity, and sex. We found little evidence for elevated cancer RRs for all sites or for gliomas among children living in high-ranking combined-source exposure areas. We found elevated RRs and a significant trend with increasing exposure level for childhood leukemia in tracts ranked highest for exposure to the combined group of 25 HAPs (RR = 1.21; 95% confidence interval, 1.03, 1.42) and in tracts ranked highest for point-source HAP exposure (RR = 1.32; 95% confidence interval, 1.11, 1.57). Our findings suggest an association between increased childhood leukemia rates and high HAP exposure, but studies involving more comprehensive exposure assessment and individual-level exposure data will be important for elucidating this relationship.

Adolescent↗
PubMed2006

Occurrence and removal of chloro-s-triazines in water treatment plants.

Atrazine, simazine, and propazine and their major chlorinated degradates (deethylatrazine, deisopropylatrazine, and didealkylatrazine) are considered as a group to be endocrine-disrupting chemicals by the U.S. Environmental Protection Agency. On this basis, regulatory action levels are currently under consideration for the total chloro-s-triazine (TCT) levels in drinking waters. To assess the concentrations of each of these species in drinking water and their treatability in conventional water treatment, a comprehensive, full-scale studywas conducted that included frequent monitoring at 33 and 47 water utilities during 2003 and 2004, respectively. Approximately 900 paired raw and treated water samples were analyzed using a gas chromatography/mass spectrometry method with preconcentration using a mixed-mode, solid-phase extraction that allowed quantitation of each species including didealkylatrazine. The results showed that atrazine concentrations were generally well within the 3 microg/L maximum contaminant level (MCL) and that simazine and propazine concentrations were generally negligible. Ninety-fifth-percentile values for the ratio of TCT/atrazine were 4.8 and 4.7, respectively. Effectiveness of conventional treatment technologies, including carbon, was observed to vary significantly. Concerns that didealkyatrazine concentrations may be high and significantly elevate the TCT appear to be unfounded. In general, the results suggest that potential treatment requirements for TCT are not likely to be any more difficult for utilities to meet than the current requirements for atrazine.

Atrazine↗
PubMed2000

Improved estimation of dermal pesticide dose to agricultural workers upon reentry.

Agricultural workers reentering fields after pesticide application to engage in hand labor activities are subject to potentially significant dermal exposures to residues on foliage and in soil. Environmental Protection Agency (EPA) guidelines for assessment of post-application exposures were originally described in the 1984 Pesticide Assessment Guidelines Subdivision K which is currently undergoing revision. A successor document will eventually appear as Series 875, Group B Postapplication Exposure Monitoring Test Guidelines. Regulatory protocols found in these documents utilize dislodgeable foliar residues, foliage-to-human-transfer coefficients, and duration of activity to estimate exposure. Dermal absorption factors are then used to estimate dose. However, the experiments from which absorption factors are derived typically involve constant or nearly constant exposures which are not consistent with assumed field exposure conditions. This can lead to inconsistent interpretation and questionable dose estimates. An AFL-CIO challenge to procedures used by EPA to estimate the dose of the fungicide captan [N-trichloromethylthio-4-cyclohexene-1,2-dicarboximide] to strawberry harvesters, which elicited a response from EPA, provides a useful opportunity for examination of the derivation and use of absorption factors. An improved, but still relatively simple, method for dermal dose estimation featuring explicit treatment of the time dependence of absorption has been developed. A benefit of the proposed method is capability for consideration of the effect of delay in post-shift washing on dose.

Agriculture↗
PubMed2006

Evaluation of a sampling strategy for estimation of long-term PM2.5 exposure for epidemiological studies.

As part of the European Community Respiratory Health Survey (ECRHS) PM2.5 (particles collected with an upper 50% cut point of 2.5 microm aerodynamic diameter) was measured using an EPA-WINS (Environmental Protection Agency Well Impactor Ninety-six) sampler. The monitoring schedule was restricted to 7 days per month for one year. Simultaneously, during this one year study period a collocated Harvard Impactor (HI) was run on a daily basis in Erfurt, Germany. Here we validated the reliability of annual, seasonal and monthly means estimated using the ECRHS scheme (measurements taken less than 25% of the whole study period) with the 'true' long-term averages, which were estimated using all available daily means. The daily PM2.5 means, obtained by both instruments operated in parallel, were only slightly different (the mean difference between EPA-WINS and HI was 1.8 microg m(-3) and 2.8 microg m(-3) for the winter means). The values obtained by the two instruments were highly correlated (r = 0.95). In view of that negligible difference, no additional bias was seen with respect to the annual and the winter means estimated by the two different sampling strategies (the difference was 1.7 microg m(-3) and 2.7 microg m(-3), respectively). Monthly means, however, can only be considered to be a crude estimate that may substantially under- or overestimate the true monthly mean value.

Air Pollutants↗
PubMed2002

Corn leaf nitrate reductase--a nontoxic alternative to cadmium for photometric nitrate determinations in water samples by air-segmented continuous-flow analysis.

Development, characterization, and operational details of an enzymatic, air-segmented continuous-flow analytical method for colorimetric determination of nitrate + nitrite in natural-water samples is described. This method is similar to U.S. Environmental Protection Agency method 353.2 and U.S. Geological Survey method 1-2545-90 except that nitrate is reduced to nitrite by soluble nitrate reductase (NaR, EC 1.6.6.1) purified from corn leaves rather than a packed-bed cadmium reactor. A three-channel, air-segmented continuous-flow analyzer-configured for simultaneous determination of nitrite (0.020-1.000 mg-N/L) and nitrate + nitrite (0.05-5.00 mg-N/L) by the nitrate reductase and cadmium reduction methods-was used to characterize analytical performance of the enzymatic reduction method. At a sampling rate of 90 h(-1), sample interaction was less than 1% for all three methods. Method detection limits were 0.001 mg of NO2- -N/L for nitrite, 0.003 mg of NO3-+ NO2- -N/L for nitrate + nitrite by the cadmium-reduction method, and 0.006 mg of NO3- + NO2- -N/L for nitrate + nitrite bythe enzymatic-reduction method. Reduction of nitrate to nitrite by both methods was greater than 95% complete overthe entire calibration range. The difference between the means of nitrate + nitrite concentrations in 124 natural-water samples determined simultaneously bythe two methods was not significantly different from zero at the p = 0.05 level.

Cadmium↗