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PubMed2002

Persistent toxic chemicals in the US food supply.

Persistent organic pollutants (POPs) have spread throughout the global environment to threaten human health and damage ecosystems, with evidence of POPs contamination in wildlife, human blood, and breast milk documented worldwide. Based on data from the US Food and Drug Administration, this article provides a brief overview of POPs residues in common foods in the United States food supply. The analysis focuses on 12 chemical compounds now targeted for an international phase out under the Stockholm Convention on POPs. The available information indicates that POPs residues are present in virtually all categories of foods, including baked goods, fruit, vegetables, meat, poultry, and dairy products. Residues of five or more persistent toxic chemicals in a single food item are not unusual, with the most commonly found POPs being the pesticides DDT (and its metabolites, such as DDE) and dieldrin. Estimated daily doses of dieldrin alone exceed US Environmental Protection Agency and US Agency for Toxic Substances Disease Control reference dose for children. Given the widespread occurrence of POPs in the food supply and the serious health risks associated with even extremely small levels of exposure, prevention of further food contamination must be a national health policy priority in every country. Implementation of the Stockholm Convention will prevent further accumulation of persistent toxic chemicals in food. Early ratification and rapid implementation of this treaty should be an urgent priority for all governments.

Diet↗
PubMed2002

Elevated birth defects in racial or ethnic minority children of women living near hazardous waste sites.

This case-control study evaluated the relationship between birth defects in racial or ethnic minority children born during 1983-1988 and the potential exposure of their mothers to contaminants at hazardous waste sites in California. Four categories of race or ethnicity were used: black/African American, Hispanic/Latino, American Indian/Alaska Native, and Asian/Pacific Islander. Case subjects were 13,938 minority infants with major structural birth defects (identified by the California Birth Defects Monitoring Program) whose mothers resided in selected counties at the time of delivery. The control group was composed of 14,463 minority infants without birth defects who were randomly selected from the same birth cohort as the case subjects. The potential for exposure was determined by whether the mother resided at the time of delivery in the same census tract as a hazardous waste site that was on the U.S. Environmental Protection Agency's National Priorities List (NPL). Racial/ethnic minority infants whose mothers had been potentially exposed to hazardous waste were at slightly increased risk for birth defects (odds ratio [OR] = 1.12, 95% confidence interval [CI] = 0.98-1.27) than were racial/ethnic minority infants whose mothers had not been potentially exposed. The greatest association was between potential exposure and neural tube defects (OR = 1.54, 95% CI = 0.93-2.55), particularly anencephaly (OR = 1.85, 95% CI = 0.91-3.75). The strongest association between birth defects and potential exposure was among American Indians/Alaska Natives (OR = 1.19, 95% CI = 0.62-2.27). Despite the limitations of this study, the consistency of these findings with previous studies suggests an association between environmental risk factors and birth defects. This is particularly relevant to minority populations. We recommend further investigation of birth defects among minority communities, particularly among American Indians/Alaska Natives. Special attention should also be paid to those defects and contaminants that consistently are associated with exposure to hazardous waste.

Adolescent↗
PubMed2006

Development of an empirical model to estimate real-world fine particulate matter emission factors: the traffic air quality model.

The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.

Air Pollutants↗
PubMed2006

Assessing and managing methylmercury risks associated with power plant mercury emissions in the United States.

Until the Clean Air Mercury Rule was signed in March 2005, coal-fired electric utilities were the only remaining, unregulated major source of industrial mercury emissions in the United States. Proponents of coal-burning power plants assert that methylmercury is not a hazard at the current environmental levels, that current technologies for limiting emissions are unreliable, and that reducing mercury emissions from power plants in the United States will have little impact on environmental levels. Opponents of coal-burning plants assert that current methylmercury exposures from fish are damaging to the developing nervous system of infants, children, and the fetus; that current technology can significantly limit emissions; and that reducing emissions will reduce exposure and risk. One concern is that local mercury emissions from power plants may contribute to higher local exposure levels, or "hot spots." The impact of the Mercury Rule on potential hot spots is uncertain due to the highly site-specific nature of the relationship between plant emissions and local fish methylmercury levels. The impact on the primary source of exposure in the United States, ocean fish, is likely to be negligible due to the contribution of natural sources and industrial sources outside the United States. Another debate centers on the toxic potency of methylmercury, with the scientific basis of the US Environmental Protection Agency's (EPA's) recommended exposure limit questioned by some and defended by others. It is likely that the EPA's exposure limit may be appropriate for combined exposure to methylmercury and polychlorinated biphenyls (PCBs), but may be lower than the available data suggest is necessary to protect children from methylmercury alone. Mercury emissions from power plants are a global problem. Without a global approach to developing and implementing clean coal technologies, limiting US power plant emissions alone will have little impact.

Air Pollution↗
PubMed1980

Photochemical smog standards--practicability or purism: an evaluation of health risk in Sydney.

The photochemical smog conditions in Sydney are related to the effects on health, real and potential. Perspectives are presented with regard to the long-range goals of the World Health Organization, past and current United States Environmental Protection Agency standards, and current New South Wales prudent and actual aspirations in the short and long term. The need for practicable, rather than puritanical, goals in relation to possible adverse health effects is emphasized. The view is expressed that, while no significant ill health will be induced in current and improving atmospheric conditions, the aesthetic appearance of Sydney is unacceptable and therefore is detrimental to the feelings and well-being which are part of health.

Air Pollutants↗
PubMed2004

Evaluation of a strategy for Toxoplasma gondii oocyst detection in water.

Several recent outbreaks of toxoplasmosis were related to drinking water. We propose a strategy for Toxoplasma oocyst detection as part of an approach to detecting multiple waterborne parasites, including Giardia and Cryptosporidium spp., by the U.S. Environmental Protection Agency method with the same sample. Water samples are filtered to recover Toxoplasma oocysts and purified on a sucrose density gradient. Detection is based on PCR and mouse inoculation (bioassay) to determine the presence and infectivity of recovered oocysts. In an experimental seeding assay with 100 liters of deionized water, a parasite density of 1 oocyst/liter was successfully detected by PCR in 60% of cases and a density of 10 oocysts/liter was detected in 100% of cases. The sensitivity of the PCR assay varied from less than 10 to more than 1000 oocysts/liter, depending on the sample source. PCR was always more sensitive than mouse inoculation. This detection strategy was then applied to 139 environmental water samples collected over a 20-month period. Fifty-three samples contained PCR inhibitors, which were overcome in 39 cases by bovine serum albumin addition. Among 125 interpretable samples, we detected Toxoplasma DNA in 10 cases (8%). None of the samples were positive by mouse inoculation. This strategy efficiently detects Toxoplasma oocysts in water and may be suitable as a public health sentinel method.

Animals↗
PubMed2005

Joint toxicity of cadmium and phenanthrene in the freshwater amphipod Hyalella azteca.

The joint toxicity of combined metals and polynuclear aromatic hydrocarbons is poorly understood and may deviate from the summed concentration responses of the individual pollutants. The freshwater amphipod Hyalella azteca was exposed to sediment-amended Cd and phenanthrene (Phen) individually and in combination using United States Environmental Protection Agency 10-day sediment toxicity bioassays with lethality and growth end points. The lethal joint toxicity of Cd and Phen was investigated separately in 24-, 48-, and 72-hour aqueous exposures. In sediment exposures, a sublethal concentration of Phen (144 mg kg(-1)) in combination with Cd increased mortality across a range of Cd concentrations and decreased the 10-day LC50 for Cd from 523 mg kg(-1) (461 to 588, 95% confidence interval [CI]) to 263 mg kg(-1) (214 to 312, 95% CI). In contrast, sublethal concentrations of Phen had no effect on the lethal toxicity of Cd in aqueous exposures. Combined sediment-amended Cd and Phen acted independently on growth rate. Rate decreases were driven primarily by Cd. Our findings indicated that association with sediment influences the joint toxicity of Cd and Phen. Thus, mixtures of Cd and Phen may cause synergistic or independent toxicity in H. azteca depending on the end point investigated and the experimental protocol employed. As an implication of these results, the interpretation of standardized toxicity bioassays, including whole-effluent toxicity tests and single-compound toxicity tests, must be made with caution. These assessment protocols may underestimate potentially hazardous mixture effects in sediment environments. Therefore, risk assessment protocols for environments containing metal-PAH mixtures must include robust methods that can detect possible interactive effects among contaminants to optimize environmental protection.

Amphipoda↗
PubMed2005

Critical evaluation of the cancer risk of dibromochloropropane (DBCP).

Dibromochloropropane (1,2-dibromo-3-chloropropane, DBCP), a pesticide used widely for over 20 years to control nematodes on crops, turf and in nurseries, was banned by the United States Environmental Protection Agency (US EPA) in 1977 because of evidence of infertility in men and induction of a variety of tumors in laboratory animals. Despite the ban on the use of DBCP, this pesticide remains persistent in soil and continues to be detected as a groundwater contaminant in areas of past high use, in particular California's Central Valley. In this review, we present a critical evaluation of the available scientific literature on the potential for DBCP to affect cancer risk, including the results of animal cancer bioassays, human epidemiological studies and in vitro and in vivo genotoxicity studies. In addition, we provide updated information on DBCP chemistry and metabolism, production and past use, current regulations, its environmental fate, potential for human exposure and current remediation efforts. Results from long-term cancer bioassays in rodents show a statistically significant increase in the incidence of malignant and benign mammary gland tumors in female rats treated orally with DBCP compared to controls and some evidence of increased incidence of mammary fibroadenomas in DBCP low-dose treated female rats exposed by inhalation. Significantly increased incidence of tumors of the forestomach occurred in both sexes of rats and mice treated orally. Rats exposed to DBCP by inhalation showed significant increases in tumors of the tunica vaginalis in males; tumors of the pharynx and adrenal gland in females; and tumors of the tongue, nasal turbinate and nasal cavity in both sexes compared to controls. Male and female mice exposed to DBCP by inhalation experienced increased tumor incidence in the lungs and nasal cavity compared to controls. Significant increases in tumors of the lung and forestomach have also been reported in female mice treated by a dermal route. Although high mortality rates in both rat and mouse bioassays limited the ability to detect tumors late in life, the induction of a variety of tumors by multiple routes of exposure in two rodent species provides clear evidence of a DBCP tumorigenic response. In vitro, in vivo and human genotoxicity studies indicate that DBCP is capable of acting as a mutagen and clastogen. Few studies have been conducted to assess whether DBCP workplace or drinking water exposures affect cancer risk in humans. While case-control, cohort and ecological epidemiology studies have not found significant, positive associations between DBCP exposure and cancer in exposed populations, these studies have numerous limitations including small numbers of participants, a lack of control for confounding factors, lack of exposure information on DBCP and other chemicals and short follow-up times. Given the persistent nature of DBCP contamination in areas of past use, efforts should be made to continue remediation efforts and follow previously exposed populations for development of certain human cancers, including breast, ovarian, stomach, respiratory, oral and nasal cancers, among others.

Animals↗
PubMed1995

A side-by-side comparison of dust collection methods for sampling lead-contaminated house dust.

The Environmental Protection Agency is required to set a standard for lead-contaminated house dust, but whether dust lead loading (micrograms/ft2) or concentration (micrograms/g) is more predictive of children's blood lead levels, which dust collection method should be used, and which surfaces should be sampled are unknown. Using a random sample of sequential births, we enrolled 205 urban children, 12 to 30 months of age, who had lived in the same house since at least 6 months of age. Samples of dust were obtained from predetermined surfaces in each child's residence using a wipe method and two vacuum methods, the Baltimore repair and maintenance method (BRM) and the dust vacuum method (DVM). Other potential sources of environmental exposure also were analyzed for lead, including soil, water, and paint. In general, dust lead loading is more predictive of children's blood lead levels than is dust lead concentration. Dust lead loading as measured with the BRM sampler explained more of the variation in children's blood lead levels than did wipe loading and DVM loading (13.7, 10.1, and 5.9%, respectively, adjusted for other significant predictors). The partial correlation between BRM lead loading and children's blood lead was significantly different than that for DVM lead loading, but it was not significantly different than that for wipe lead loading. Of the four surfaces measured, noncarpeted floors and interior window sills or wells were significantly associated with children's blood lead levels in multiple regression models. These data indicate that dust lead loading is more predictive of children's blood lead levels than is dust lead concentration and that, to determine if a housing unit is safe for children, noncarpeted floors and interior window sills or window wells should be measured using either the BRM or wipe sampling method.

Air Pollution, Indoor↗
PubMed1993

Environmental monitoring and dose assessment following the December 1991 K-reactor aqueous tritium release.

Between 22 December and 25 December 1991, approximately 570 L of tritiated water was released from the K Reactor at the Savannah River Site. Analyses of river flow rates and measured tritium concentrations showed that approximately 210 TBq of tritium had been released from the reactor and was being transported down the Savannah River. Elevated tritium concentrations in the Savannah River were first detected on 26 December 1991. The maximum measured tritium concentration at Highway 301 (a major sampling point 37 km downstream of the Savannah River Site) was 2.5 Bq mL-1. A hypothetical maximum individual located at Highway 301 would have received a drinking water dose of approximately 0.35 microSv, less than 1% of the Environmental Protection Agency's 40 microSv y-1 drinking water standard. Concentrations at the intake canals to two water treatment facilities, approximately 160 km downstream, began to rise above normal on 28 December. The population dose to users of the downstream domestic water supplies and consumers of Savannah River biota was estimated to be 4.7 x 10(-3) person-Sv.

Environmental Monitoring↗
PubMed1980

Mutagenicity evaluation of chemical pesticides.

Over the last few decades, the use of chemical pesticides has increased dramatically in the U.S. This relatively sudden increase greatly concerns the U.S. Environmental Protection Agency (EPA), since it has the responsibility for ensuring the safety of all pesticides used in the U.S. In response to this concern, EPA has established a review program, the Rebuttable Presumption Against Registration (RPAR), for periodically reassessing the mutagenic and carcinogenic potential of pesticide compounds. This paper presents a review and evaluation of the data reported in the literature on six chemical pesticides suspect for mutagenic potential. The pesticide chemicals discussed are maleic hydrazide; rotenone; monuron; diallate; triallate, and benomyl.

Animals↗
PubMed1991

An integrated exposure/pharmacokinetic based approach to the assessment of complex exposures. Lead: a case study.

A problem in evaluating the hazard represented by an environmental toxicant is that exposures can occur via multiple media such as water, land, and air. Lead is one of the toxicants of concern that has been associated with adverse effects on heme metabolism, serum vitamin D levels, and the mental and physical development of infants and children exposed at very low environmental levels. Effects of lead on development are particularly disturbing in that the consequences of early delays or deficits in physical or mental development may have long-term consequences over the lifetime of affected individuals. Experimental and epidemiologic studies have indicated that blood lead levels in the range of 10-15 micrograms/dl, or possibly lower, are likely to produce subclinical toxicity. Since a discernible threshold has not been demonstrated, it is prudent to preclude development of a Reference Dose (RfD) for lead. As an alternate, the U.S. Environmental Protection Agency (U.S. EPA) has developed the uptake/biokinetic lead model that provides a means for evaluating the relative contribution of various media to establishing blood lead levels in children. This approach will allow for the identification of site- and situation-specific abatement strategies based on projected blood lead levels in vulnerable human populations exposed to lead in air, diet, water, soil/dust, and paint; thus making it possible to evaluate regulatory decisions concerning each medium on blood levels and potential health effects.

Environmental Exposure↗
PubMed2002

Delineation of groundwater contamination around an ash pond: geochemical and GIS approach.

The study has investigated the levels of metal contamination in groundwater due to particulate matter fallout and leaching from ash pond and assigned contamination indices for the adjacent localities around an ash disposal site with application of geographic information systems (GIS). Fe, Ba, Cu, Mn, S, Pb, V, and Zn were found to be the major contaminants in groundwater. Enrichment factors (EF) of these elements with respect to the United States Environmental Protection Agency (USEPA) maximum contaminant levels show high values for Mn, Fe, and Pb in groundwater. The zone of attenuation for Ba, Fe, Cu, Mn, S, and Zn in groundwater is about 600-900 m from the ash pond, while Pb did not show any significant attenuation even at a distance of 1200 m. Tube wells around Rankasingha and Kukurhanga villages are most contaminated whereas open wells of Lachhmanpur, Kaniapada, and Kurudul villages showed higher degrees of contamination.

Environmental Monitoring↗
PubMed2002

Risks to the public from historical releases of radionuclides and chemicals at the Rocky Flats Environmental Technology Site.

This paper summarizes the methods and results of estimating risks of cancer incidence resulting from plutonium, carbon tetrachloride, and beryllium releases from operations at the Rocky Flats Environmental Technology Site, near Denver, Colorado, from 1953 through 1989. The key findings show that people who lived near the facility were exposed to plutonium mainly through inhalation during routine operations, from a major fire in 1957, and from plutonium resuspended from contaminated soil from an outdoor drum storage area, called the 903 Area. Results were presented for five exposure scenarios that were location-independent. Individuals described by the laborer scenario received the highest risk of all scenarios considered. Upper bound (95th percentile) incremental lifetime cancer incidence risks for the laborer scenario were in about the 10(-4) range (1 chance in 10,000) for developing cancer from Rocky Flats plutonium releases during a lifetime. At the 5th percentile level, the maximum cancer risk was about 10(-7) (1 chance in 10 million) for developing cancer during a lifetime. Estimated cancer risks at the 95th percentile level are within the range of for acceptable risks established by the US Environmental Protection Agency of 10(-6) to 10(-4). Carbon tetrachloride was found to be the chemical that presented the highest risk to the public. The 5th and 95th percentile risk values for exposure to carbon tetrachloride were 9.2x10(-7) and 2.5x10(-5), respectively.

Adolescent↗
PubMedDate not supplied

Toxicity of polyacrylamide and acrylamide monomer.

The purpose of this paper is to present information gathered regarding, in general, the physical characteristics, and, in particular, the possible toxic nature of polyacrylamide A short discussion of the properties and toxicity of the acrylamide monomer is also included. The United States government, specifically the Food and Drug Administration and the Environmental Protection Agency, already regulates several uses of polyacrylamide; criteria and standards have been established based on numerous toxicological studies of both polyacrylamide and acrylamide. These studies are reviewed and summarized. The regulations generally restrict both the amount of residual acrylamide monomer in the polyacrylamide and the amount of polymer that may be used in the specified application. By imposing this type of restriction, a maximum limit on the amount of acrylamide in contact with food or drinking water can be indirectly achieved.

Acrylic Resins↗
PubMed2002

Modeling mobile source emissions during traffic jams in a micro urban environment.

Urbanization typically involves a continuous increase in motor vehicle use, resulting in congestion known as traffic jams. Idling emissions due to traffic jams combine with the complex terrain created by buildings to concentrate atmospheric pollutants in localized areas. This research simulates emissions concentrations and distributions for a congested street in Minsk, Belarus. Ground-level (up to 50-meters above the street's surface) pollutant concentrations were calculated using STAR (version 3.10) with emission factors obtained from the U.S. Environmental Protection Agency, wind speed and direction, and building location and size. Relative emissions concentrations and distributions were simulated at 1-meter and 10-meters above street level. The findings demonstrate the importance of wind speed and direction, and building size and location on emissions concentrations and distributions, with the leeward sides of buildings retaining up to 99 percent of the emitted pollutants within 1-meter of street level, and up to 77 percent 10-meters above the street.

Air Movements↗
PubMed2001

The impact of pollution from a mercury processing plant in KwaZulu-Natal, South Africa, on the health of fish-eating communities in the area: an environmental health risk assessment.

The objective of this study was to determine the human health risk associated with fish consumption in a contaminated area downstream from a mercury processing plant in KwaZulu-Natal, South Africa. The study population consisted of fish consumers living in close proximity to the u'Mgeni River and the Inanda Dam downstream from the plant. A control group was selected from the area upstream from the mercury plant as far as the Nagle Dam. Total daily mercury consumption per kilogram body weight per day was calculated for each person included in the study. These data were compared with the tolerable daily intake standard published by the World Health Organization, as well as to the United States Environmental Protection Agency's reference dose. Human hair samples obtained from the study population and a control group were analysed for mercury content. The results of the risk estimation indicated that the study population is at risk. Human hair samples, however, indicated that dangerous levels of mercury had not yet been consumed. Humans in this study area could be subject to an excessive health risk from mercury as a result of their fish consumption. Fish mercury levels in the contaminated area should be monitored closely.

Adolescent↗
PubMed2001

Performance evaluation of laser-induced breakdown spectrometry as a multimetal continuous emission monitor.

Laser-induced breakdown spectroscopy (LIBS) has been evaluated as a multimetal continuous emissions monitor (CEM) at the U.S. Environmental Protection Agency (EPA) rotary kiln incinerator simulator (RKIS) facility in Raleigh, NC. Two detection systems with a bifurcated optical fiber bundle were used for simultaneously monitoring the concentrations of Be, Cd, Cr, and Hg in the test. Two calibration techniques were evaluated in the laboratory for the field measurements. On-line calibration of relative metal concentration was also performed in the simulated incinerator gas stream. Toxic metal concentrations measured with LIBS have been compared with the EPA reference method (RM) results.

Air Pollutants↗