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Showing papers in "Environmental Health Perspectives in 1991"


Journal ArticleDOI
TL;DR: The estrogenic properties of alkylphenols, specifically nonylphenol, indicate that the use of plasticware containing these chemicals in experimental and diagnostic tests may lead to spurious results, and these compounds as well as alkyLphenol polyethoxylates may also be potentially harmful to exposed humans and the environment at large.
Abstract: Alkylphenols are widely used as plastic additives and surfactants. We report the identification of an alkylphenol, nonylphenol, as an estrogenic substance released from plastic centrifuge tubes. Th...

1,043 citations


Journal ArticleDOI
TL;DR: Knowing the processes that control the migration and transformation of chromium is important in developing and selecting effective, cost-efficient remediation designs for chromium-contaminated sites.
Abstract: The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium-laden waters. Redox reactions, chemical speciation, adsorption/desorption phenomena, and precipitation/dissolution reactions control the transformation and mobility of chromium. The reduction of CrVI to CrIII can occur in the presence of ferrous iron in solution or in mineral phases, reduced sulfur compounds, or soil organic matter. At neutral to alkaline pH, the CrIII precipitates as amorphous hydroxides or forms complexes with organic matter. CrIII is oxidized by manganese dioxide, a common mineral found in many soils. Solid-phase precipitates of hexavalent chromium such as barium chromate can serve either as sources or sinks for CrVI. Adsorption of CrVI in soils increases with decreasing chromium concentration, making it more difficult to remove the chromium as the concentration decreases during pump-and-treat remediation. Knowledge of these chemical and physical processes is important in developing and selecting effective, cost-efficient remediation designs for chromium-contaminated sites.

457 citations


Journal ArticleDOI
TL;DR: Bone as a source of lead to the rest of the body and as a record of past lead exposure is discussed and proposed numerical values for the changes in blood lead levels that occur with changes in turnover rates are presented.
Abstract: This article discusses bone as a source of lead to the rest of the body and as a record of past lead exposure. Bone lead levels generally increase with age at rates dependent on the skeletal site and lead exposure. After occupational exposure, the slow decline in blood lead, a 5- to 19-year half-life, reflects the long skeletal half-life. Repeated measurements of bone lead demonstrate the slow elimination of lead from bone. Stable isotope ratios have revealed many details of skeletal uptake and subsequent release. The bulk turnover rates for compact bone are about 2% per year and 8% for spine. Turnover activity varies with age and health. Even though lead approximates calcium, radium, strontium, barium, fluorine, and other bone seekers, the rates for each are different. A simple, two-pool (bone and blood) kinetic model is presented with proposed numerical values for the changes in blood lead levels that occur with changes in turnover rates. Two approaches are offered to further quantify lead turnover. One involves a study of subjects with known past exposure. Changes in the ratio of blood lead to bone lead with time would reflect the course of bone lead availability. Also, stable isotopes and subjects who move from one geographical area to another offer opportunities. Sequential isotope measurements would indicate how much of the lead in blood is from current exposure or bone stores, distinct from changes in absorption or excretion.

405 citations


Journal ArticleDOI
TL;DR: High levels of polynuclear aromatic hydrocarbon (PAH) carcinogens commonly occur in aquatic systems where neoplasms arise in fish and other animals andenzymes that transform PAHs can act in initiatin formation.
Abstract: High levels of polynuclear aromatic hydrocarbon (PAH) carcinogens commonly occur in aquatic systems where neoplasms arise in fish and other animals. Enzymes that transform PAHs can act in initiatin...

366 citations


Journal ArticleDOI
TL;DR: Current knowledge on mercury and monomethylmercury is reviewed with regard to their environmental fate and the potential for human health effects and the present and future questions of whether the environmental impact is of local, regional, or hemispheric significance remain remain.
Abstract: Global atmospheric changes carry the potential to disrupt the normal cycling of mercury and its compounds. Acid rain may increase methylmercury levels in freshwater fish. Global warming and increased ultraviolet radiation may affect the global budget of methylmercury, including its formation and degradation in both biotic and abiotic environments. In this article we review current knowledge on mercury and monomethylmercury with regard to their environmental fate and the potential for human health effects. Recent findings indicate that atmospheric Hg deposition readily accounts for the total mass of Hg in fish, water, and sediment of Little Rock Lake, a representative temperate seepage lake in north-central Wisconsin. It is strikingly evident that modest increases in atmospheric Hg loading could lead directly to elevated levels in the fish stock. It is doubtful, given the experimental limitations in many recent studies, that the temporal pattern for Hg emissions, for background atmospheric Hg concentrations, and for changes in Hg depositional fluxes has been identified. Thus, the present and future questions of whether the environmental impact is of local, regional, or hemispheric significance remain. Contemporary investigations must address these important questions. Human exposure to methylmercury in the United States is probably increasing due to increased consumption of fish and fish products. A recent epidemiological investigation indicates high susceptibility to brain damage during prenatal exposures to Hg. An important objective for future investigation is to establish the lowest effect level for human exposure to methylmercury.

346 citations


Journal ArticleDOI
TL;DR: Although relatively little is known of lead kinetics during these critical periods, it is likely that bone lead is mobilized and transferred to the more bioavailable compartment of the maternal circulation, with potential toxic effects on the fetus and the mother.
Abstract: Advances in understanding the distribution and retention of lead in mineralized tissues are important for two reasons: first, bone lead may be a more accurate dosimeter of integrated absorption associated with chronic exposures, and second, bone lead may be a source of internal exposure to the host organism. Little attention has been paid to this second aspect, the remobilization of lead from bone. Mobilization of lead from bone is likely to occur during periods of altered mineral metabolism; since calciotropic factors determine the uptake and storage of lead in this compartment, changes in calcium-related regulatory factors are likely to affect lead compartmentation. Calcium metabolism changes drastically in humans during pregnancy and lactation; although relatively little is known of lead kinetics during these critical periods, it is likely that bone lead is mobilized and transferred to the more bioavailable compartment of the maternal circulation, with potential toxic effects on the fetus and the mother.

308 citations


Journal ArticleDOI
TL;DR: Compartmental analysis indicates that the kinetic distribution and behavior of intracellular lead in osteoblasts and osteoclasts is similar to several other cell types, suggesting that the toxic effects of lead on bone cell function may be produced by perturbation of the calcium and cAMP messenger systems in these cells.
Abstract: To fully understand the significance of bone as a target tissue of lead toxicity, as well as a reservoir of systemic lead, it is necessary to define the effects of lead on the cellular components of bone Skeletal development and the regulation of skeletal mass are ultimately determined by the four different types of cells: osteoblasts, lining cells, osteoclasts, and osteocytes These cells, which line and penetrate the mineralized matrix, are responsible for matrix formation, mineralization, and bone resorption, under the control of both systemic and local factors Systemic components of regulation include parathyroid hormone, 1,25-dihydroxyvitamin D3, and calcitonin: local regulators include numerous cytokines and growth factors Lead intoxication directly and indirectly alters many aspects of bone cell function First, lead may indirectly alter bone cell function through changes in the circulating levels of those hormones, particularly 1,25-dihydroxyvitamin D3, which modulate bone cell function These hormonal changes have been well established in clinical studies, although the functional significance remains to be established Second, lead may directly alter bone cell function by perturbing the ability of bone cells to respond to hormonal regulation For example, the 1,25-dihydroxyvitamin D3-stimulated synthesis of osteocalcin, a calcium-binding protein synthesized by osteoblastic bone cells, is inhibited by low levels of lead Impaired osteocalcin production may inhibit new bone formation, as well as the functional coupling of osteoblasts and osteoclasts Third, lead may impair the ability of cells to synthesize or secrete other components of the bone matrix, such as collagen or bone sialoproteins (osteopontin) Finally, lead may directly effect or substitute for calcium in the active sites of the calcium messenger system, resulting in loss of physiological regulation The effects of lead on the recruitment and differentiation of bone cells remains to be established Compartmental analysis indicates that the kinetic distribution and behavior of intracellular lead in osteoblasts and osteoclasts is similar to several other cell types Many of the toxic effects of lead on bone cell function may be produced by perturbation of the calcium and cAMP messenger systems in these cells

305 citations


Journal ArticleDOI
TL;DR: The major links in the cycling of chromium in soils and in natural waters are between chromium(III) and chromium (VI).
Abstract: The major links in the cycling of chromium in soils and in natural waters are between chromium(III) and chromium (VI) Between the larger links are lesser links involving processes of mobilization and oxidation of CrIII and reduction of CrVI The gaps are mainly in our understanding of the factors that control these processes If soluble CrIII is added to an "average" soil, a portion of it will become immediately oxidized by manganese oxides to CrVI The rest of the CrIII may remain reduced for long periods of time, even in the presence of electron-accepting manganese oxides However, this less available CrIII can be mobilized by low molecular weight organic complexers and then oxidized where redox conditions are optimal Usually part of any CrVI added to a soil or sediment will be reduced instantly, especially under acid conditions On the other hand, high concentrations of polluting CrVI may quickly exhaust the readily available reducing power of the matrix material and excess CrVI, the thermodynamically stable form in air, may persist for years in soils or lagoons without reduction Cleanup of chromium pollution must involve the surrounding of both CrIII and CrVI with excesses of slowly available reducing substances and sealing them permanently from inputs of atmospheric oxygen Monitoring the effectiveness of the measures is mandatory, but fortunately the chemical testing for CrVI in soil and water is simple and problem free compared with most colorimetric determinations

300 citations


Journal ArticleDOI
Robert E. Shope1
TL;DR: Global warming may lead to changes in water ecology that could enhance similar spread of cholera in North America and other infectious diseases such as LaCrosse encephalitis and Lyme disease are caused by agents closely dependent on the integrity of their environment.
Abstract: The effects of global climate change on infectious diseases are hypothetical until more is known about the degree of change in temperature and humidity that will occur. Diseases most likely to increase in their distribution and severity have three-factor (agent, vector, and human being) and four-factor (plus vertebrate reservoir host) ecology. Aedes aegypti and Aedes albopictus mosquitoes may move northward and have more rapid metamorphosis with global warming. These mosquitoes transmit dengue virus, and Aedes aegypti transmits yellow fever virus. The faster metamorphosis and a shorter extrinsic incubation of dengue and yellow fever viruses could lead to epidemics in North America. Vibrio cholerae is harbored persistently in the estuaries of the U.S. Gulf Coast. Over the past 200 years, cholera has become pandemic seven times with spread from Asia to Europe, Africa, and North America. Global warming may lead to changes in water ecology that could enhance similar spread of cholera in North America. Some other infectious diseases such as LaCrosse encephalitis and Lyme disease are caused by agents closely dependent on the integrity of their environment. These diseases may become less prominent with global warming because of anticipated modification of their habitats. Ecological studies will help us to understand more fully the possible consequences of global warming. New and more effective methods for control of vectors will be needed.

239 citations


Journal ArticleDOI
TL;DR: Comparative analysis of the spectrum of mutations show that while G to A transitions were the most frequent mutations in pancreatic and colo-rectal tumors, G to T transversions were more prevalent in lung carcinomas.
Abstract: The frequency of point mutations at codons 12 and 13 of the c-K-ras gene has been determined in a panel of more than 400 human tumors. Mutant c-K-ras genes were detected in about 75% of adenocarcinomas of the pancreas (n = 84); 40% of adenomas (n = 72) and carcinomas (n = 244) of the colon end rectum; 30% of carcinomas of the bile duct (n = 19); 25% of carcinomas of the lung (n = 92), and in lower frequency in other carcinomas, including liver, stomach, and kidney. No mutations were found in carcinomas of the breast, prostate, esophagus, and gall bladder, among others. Comparative analysis of the spectrum of mutations show that while G to A transitions were the most frequent mutations in pancreatic and colo-rectal tumors, G to T transversions were more prevalent in lung carcinomas. The aspartic acid mutation at codon 13 (GGC----GAC) was relatively frequent in colo-rectal tumors but rare in pancreatic and lung carcinomas. The differences in the mutation spectrum of the c-K-ras gene in cancers of the gastrointestinal and respiratory tracts are suggestive of differential exposure to genotoxic agents.

217 citations


Journal ArticleDOI
Ruth Sager1
TL;DR: Two independent lines of experimental evidence are presented in support of the hypothesis that senescence is a normal mechanism of tumor suppression, a homeostatic device designed through evolution to limit cell proliferation irreversibly and thereby to protect the organism against cancer.
Abstract: Two independent lines of experimental evidence are presented in support of the hypothesis that senescence is a normal mechanism of tumor suppression, a homeostatic device designed through evolution to limit cell proliferation irreversibly and thereby to protect the organism against cancer. One set of experiments uses normal human foreskin fibroblasts, transfected at early passage with SV40 DNA and subsequently infected with the K-ras virus. If the cells are immortal prior to infection, they become tumorigenic and make large tumors in nude mice, whereas if they are not immortal, though expressing SV40 T-antigen, they make tiny tumors that senesce in the test mouse after as many doublings as similar cells make in culture. This result demonstrates that immortalization is essential for progressive tumor growth in vivo. The second set of experiments demonstrate that normal human mammary epithelial cells can be immortalized by transfection with viral DNA from human papilloma virus 16 or 18, although these viruses have not been associated with breast cancer. The effective immortalization and other premalignant changes induced by human papilloma virus transfection are accompanied by chromosome changes that may contribute to the partially transformed phenotypes. None of the cloned or pooled transfectants have been tumorigenic in the nude mouse assay. Here, too, immortalization is experimentally separable from tumor-forming ability.

Journal ArticleDOI
TL;DR: In addition to studying the pathogenic role of oncogenes, this work is attempting to define negative growth-regulating genes that have tumor-suppressive effects for human lung carcinomas, and involves loss of heterozygosity studies, monochromosome- cell fusion, and cell-cell fusion studies.
Abstract: The functional role of oncogenes in human lung carcinogenesis has been investigated by transfer of activated oncogenes into normal cells or an immortalized bronchial epithelial cell line, BEAS-2B. Transfection of v-Ha-ras, Ki-ras, or the combination of myc and raf into BEAS-2B cells produced tumorigenic cell lines, while transfection of raf or myc alone produced nontumorigenic cell lines. In addition to studying the pathogenic role of oncogenes, we are attempting to define negative growth-regulating genes that have tumor-suppressive effects for human lung carcinomas. Our strategy to identify tumor-suppressor genes involves loss of heterozygosity studies, monochromosome-cell fusion, and cell-cell fusion studies. Loss of heterozygosity studies have revealed consistent allelic DNA sequence deletions on chromosome 17p in squamous cell carcinomas, while large cell carcinomas and adenocarcinomas retained this locus. Mutations in p53, a tumor-suppressor gene located on chromosome 17p, have been observed. Cell-cell hybrid clones produced from fusion of nontumorigenic BEAS-2B cells with tumorigenic HuT292DM cells generally are nontumorigenic. The mechanistic role of the known tumor-suppressor genes Rb-1 and p53 in the development of human lung carcinomas is being investigated in this epithelial cell model of human bronchogenic carcinogenesis.

Journal ArticleDOI
TL;DR: It appears that day-to-day mortality fluctuations are much more sensitive to weather than to pollution concentrations, as the oppressive category associated with the greatest mortality possessed levels of six major pollutants that were not noteworthy.
Abstract: The objective of this study is to introduce a new procedure to determine the impact of climate on human mortality with the use of a synoptic climatological approach. The holistic nature of synoptic categories allows for the simultaneous evaluation of numerous weather elements as they realistically appear within air masses. In addition, this approach allows for a better distinction between pollution-induced mortality and weather-induced mortality. A synoptic categorization was performed for St. Louis, Missouri, and each category was evaluated in terms of its mean daily mortality. Of 10 summer categories found in St. Louis, one possessed the highest mean mortality by far, and 8 of the top 10 mortality days in St. Louis occurred when this category was present. Further analysis determined that long, consecutive day periods of this hot, oppressive category are associated with a continuing rise in mortality. It was determined that the procedure described here has the potential to be used in a weather/mortality watch-warning system. Finally, it appears that day-to-day mortality fluctuations are much more sensitive to weather than to pollution concentrations, as the oppressive category associated with the greatest mortality possessed levels of six major pollutants that were not noteworthy.

Journal ArticleDOI
TL;DR: The hypothesis that lesions in wild English sole can be caused by exposure to certain hepatoxic and hepatocarcinogenic xenobiotic compounds in the marine environment is based on the demonstration of significant and consistent statistical associations between levels of aromatic hydrocarbons in sediment and prevalences of these idiopathic liver lesions.
Abstract: English sole (Parophrys vetulus) inhabiting polluted waterways and embayments of Puget Sound, Washington, are affected with a variety of multiple, co-occurring idiopathic hepatic lesions, including unique degenerative conditions, putatively preneoplastic foci of cellular alteration, and neoplasms. Results of a statistical analysis of the patterns of co-occurrence of these lesions in wild English sole are consistent with the concept that these lesions represent morphologically identifiable steps forming a sequence of progression ultimately leading to the development of hepatic neoplasms. This progressive sequence parallels the pattern identified in experimental models of chemically induced hepatocarcinogenesis in rodents. The rationale for the hypothesis that these lesions in wild English sole can be caused by exposure to certain hepatoxic and hepatocarcinogenic xenobiotic compounds in the marine environment is based on the demonstration of significant and consistent statistical associations between levels of aromatic hydrocarbons (AHs) in sediment and prevalences of these idiopathic liver lesions; a significant contribution by sediment AHs to the variability in hepatic neoplasm prevalence in a logistic regression model; significantly increased probabilities for several idiopathic lesions in sole from chemically contaminated sites in Puget Sound; significant correlations between uptake of polycyclic aromatic hydrocarbons, as measured by levels of fluorescent metabolites of aromatic compounds in bile of sole, and prevalences of several hepatic lesion types; and experimental induction of unique degenerative, proliferative, and putatively preneoplastic focal lesions in English sole injected with either benzo(a)pyrene or a polycyclic aromatic hydrocarbons (PAH) enriched fraction of an extract from a contaminated urban sediment from Puget Sound.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: This paper has compiled listings of chemicals having like carcinogenic target sites for each of the 34 organs or systems for which histopathology diagnoses have been recorded routinely, and permits an evaluation of how well chemically induced cancers in a particular organ in one sex or species will predict or correlate with the othersex or species.
Abstract: The carcinogenicity data base used for this paper originated in the late 1960s by the National Cancer Institute and since 1978 has been continued and made more comprehensive by the National Toxicology Program. The extensive files contain among other sets of information detailed pathology data on more than 400 long-term (most often 24 month) chemical carcinogenesis studies, comprised of nearly 1600 individual experiments having at least 10 million tissue sections that have been evaluated for toxicity and carcinogenicity. Using the current data set of 379 studies made up of 1394 experiments, we have compiled listings of chemicals having like carcinogenic target sites for each of the 34 organs or systems for which histopathology diagnoses have been recorded routinely. The most common tumor site is the liver (15% of all experiments), followed in rank order by: lung, hematopoietic system and kidneys, mammary glands, forestomach, thyroid glands, Zymbal glands, urinary bladder, skin and uterus/cervix, and circulatory system and adrenal glands. These compilations are most useful for maintaining a historic perspective when evaluating the carcinogenicity of contemporary experiments. Equally important, the chemical-tumor-organ connection permits an evaluation of how well chemically induced cancers in a particular organ in one sex or species will predict or correlate with the other sex or species. Using liver cancers as an example, the overall interspecies concordance is 80%. Likewise target site predictions can be made for chemicals selected for study that may be similar to those already evaluated; thereby experimental protocols could be adjusted to allow, for example, more extensive pathology on preselected target organs (i.e., serial sections of the kidney). Further from these observations, one could decide to use two strains of mice to evaluate a short-chain chlorinated aliphatic compound or to study a human carcinogen in a sex-species known to develop chemically induced tumors in the same site observed in humans. Structural classes of chemicals having a propensity for certain organs can be easily identified from these data. Sex-species responders to particular induced cancers become clearly evident, such as in the ovary of female mice or in the kidney of male rats.

Journal ArticleDOI
TL;DR: The nature of chromium(VI)-induced DNA damage appears to be dependent on the reactive intermediates, i.e. chromium (V) or hydroxyl radical, produced during the reduction of chromation(VI).
Abstract: The types of reactive intermediates generated upon reduction of chromium(VI) by glutathione or hydrogen peroxide and the resulting DNA damage have been determined. In vitro, reaction of chromium(VI...

Journal ArticleDOI
TL;DR: In comparison neighborhoods with no nearby waste sites, environmental worry has been found to be associated with symptom occurrence as well, and potential explanations are presented, including the possibility that odors serve as a sensory cue for the manifestation of stress-related illness among individuals concerned about the quality of their neighborhood environment.
Abstract: Retrospective symptom prevalence data, collected from over 2000 adult respondents living near three different hazardous waste sites, were analyzed with respect to both self-reported "environmental worry" and frequency of perceiving environmental (particularly petrochemical) odors. Significant positive relationships were observed between the prevalence of several symptoms (headache, nausea, eye and throat irritation) and both frequency of odor perception and degree of worry. Headaches, for example, showed a prevalence odds ratio of 5.0 comparing respondents who reported noticing environmental odors frequently versus those noticing no such odors and 10.8 comparing those who described themselves as "very worried" versus "not worried" about environmental conditions in their neighborhood. Elimination of respondents who ascribed their environmental worry to illness in themselves or in family members did not materially affect the strength of the observed associations. In addition to their independent effects, odor perception and environmental worry exhibited positive interaction as determinants of symptom prevalence, as evidenced by a prevalence odds ratio of 38.1 comparing headaches among the high worry/frequent-odor group and the no-worry/no-odor group. In comparison neighborhoods with no nearby waste sites, environmental worry has been found to be associated with symptom occurrence as well. Potential explanations for these observations are presented, including the possibility that odors serve as a sensory cue for the manifestation of stress-related illness (or heightened awareness of underlying symptoms) among individuals concerned about the quality of their neighborhood environment.

Journal ArticleDOI
TL;DR: The chemistry, environmental fate, health effects, and human exposure potentials for this waste are described.
Abstract: Chromite ore processing residue occurs at over 130 sites in Hudson County, New Jersey. Many of these sites are in urban residential areas. This waste is a result of 70 years of chromate and bichromate chemical manufacturing. At least 15% of the sites contain total chromium concentrations greater than 10,000 mg/kg, with hexavalent content ranging from about 1 to 50%. Continuing leaching of this waste results in yellow-colored surface water runoff and yellow deposits on the soil surface and inside basement walls. The chemistry, environmental fate, health effects, and human exposure potentials for this waste are described.

Journal ArticleDOI
TL;DR: Upper-bound lifetime risks of cancer are calculated for both indoor and outdoor sources of 12 VOCs and about 23 pesticides measured in the TEAM Studies, supplemented by calculations based on other studies for some additional pollutants, including radon and environmental tobacco smoke.
Abstract: Environmental Protection Agency TEAM (Total Exposure Assessment Measurement) Studies have measured exposures of about 800 persons to 25 volatile organic compounds (VOCs) and exposures of about 300 ...

Journal ArticleDOI
TL;DR: The results suggest that a halving of the population mean blood lead level would reduce myocardial infarctions by approximately 24,000 events per year and incidence of all cardiovascular disease by over 100,000, which suggest a small attributable risk compared to the vast incidence of cardiovascular disease in the U.S., but a large attributable riskCompared to most environmental toxins.
Abstract: Lead has been shown to be associated with elevated blood pressure in males in the NHANES II survey and in numerous other studies. This study confirms the association in males aged 20 to 74 and docu...

Journal ArticleDOI
TL;DR: The fetotoxic effects of toLUene have been demonstrated in controlled studies in animals and are comparable to those observed in humans who have abused toluene-containing products before or during pregnancy.
Abstract: Toluene is a widely used industrial solvent, and humans may also have high exposures to toluene from the deliberate inhalation ("sniffing") of paint reducer, paint thinner, or paint for their narcotic effects. A number of case reports describe neonatal effects that have been attributed to toluene abuse during pregnancy. These effects may include intrauterine growth retardation, premature delivery, congenital malformations, and postnatal developmental retardation. The possibility of exposures to other fetotoxic agents, either as impurities or admixtures in toluene-containing products, or by deliberate or accidental exposures to other chemicals or drugs, cannot be excluded in these cases. The fetotoxic effects of toluene have been demonstrated in controlled studies in animals and are comparable to those observed in humans who have abused toluene-containing products before or during pregnancy. Intrauterine developmental retardation is the most clearly established effect in animals, as evidenced by decreased late fetal weight and retarded skeletal development. There is also limited evidence in rodents for skeletal and kidney abnormalities, as well as some evidence for effects on postnatal physical and possibly neurobehavioral development. Estimated daily exposures from experimental studies in animals are compared to estimated human daily intakes at the occupational permissible exposure level and at the level reported to produce euphoria in humans. Acceptable human intakes under California's Proposition 65 and under U.S. Environmental Protection Agency procedures are discussed.

Journal ArticleDOI
TL;DR: Chromate-induced ATN and LMW proteinuria in chromium workers, nevertheless, raise the possibility that low-level, long-term exposure may produce persistent renal injury.
Abstract: Kidney disease is often cited as one of the adverse effects of chromium, yet chronic renal disease due to occupational or environmental exposure to chromium has not yet been reported. Occasional ca...

Journal ArticleDOI
TL;DR: To obtain some insight into the questions of whether there is any risk to human health from consuming fish and crustaceans from urban areas, techniques must be developed that measure metabolites of carcinogens, such as PAHs, in edible tissue.
Abstract: Studies with several bottom fish species from urban waterways show that of the identified xenobiotic chemicals in bottom sediments, polycylic aromatic hydrocarbons (PAHs) are the most strongly asso...

Journal ArticleDOI
TL;DR: A compendium of carcinogenesis bioassay results organized by target organ is presented, and an analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa.
Abstract: A compendium of carcinogenesis bioassay results organized by target organ is presented for 533 chemicals that are carcinogenic in at least one species. This compendium is based primarily on experiments in rats or mice; results in hamsters, nonhuman primates, and dogs are also reported. The compendium can be used to identify chemicals that induce tumors at particular sites, and to determine whether target sites are the same for chemicals positive in more than one species. The Carcinogenic Potency Database (CPDB), which includes results of 3969 experiments, is used in the analysis. The published CPDB includes details on each test, and literature references. Chemical carcinogens are reported for 35 different target organs in rats or mice. More than 80% of the carcinogens in each of these species are positive in at least one of the 8 most frequent target sites: liver, lung, mammary gland, stomach, vascular system, kidney, hematopoietic system, and urinary bladder. An analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa. Among chemicals tested in both species, 76% of rat carcinogens are positive in mice, and 71% of mouse carcinogens are positive in rats. Prediction is less accurate to the same target site: 52% of rat carcinogens are positive in the same site in mice, and 48% of mouse carcinogens are positive in the same site in rats. The liver is the most frequent site in common between rats and mice.

Journal ArticleDOI
TL;DR: The findings demonstrate the major role of traditional pottery as a contributor to blood lead levels in this population of women from middle to low socioeconomic status and emphasize the need for interventions to produce lead-free pottery.
Abstract: The aim of this study was to determine the main contributors to blood lead levels in a population of women from middle to low socioeconomic status in the southwestern part of Mexico City. Within this area, the authors selected a random sample of 200 women. Age ranged from 21 to 57 years, with a mean of 36 years. Among 99 women who agreed to participate in this study, blood lead levels ranged from 1 to 52 micrograms/dL, with a mean of 10.6 micrograms/dL. Five percent of the women had a blood lead level over 25 micrograms/dL and 22% over 15 micrograms/dL. There was no significant trend in blood levels according to age. The main determinants of blood lead levels were higher socioeconomic status (presence of telephone in the house, t-test, p = 0.01) and using lead-glazed ceramics (LGC) to prepare food (t-test, p less than 0.005). There was a significant increasing trend in blood lead levels with increasing frequency of consumption of food prepared in LGC (test for trend, p = 0.0008). Among the dishes prepared in LGC, the main determinant was the consumption of stew. Time spent outdoors and consumption of tap water and of canned food were not important determinants of blood lead levels. The population attributable risk of high blood level (less than 15 micrograms/dL) due to the use of LGC was 58%. These findings demonstrate the major role of traditional pottery as a contributor to blood lead levels in this population and emphasize the need for interventions to produce lead-free pottery.

Journal ArticleDOI
TL;DR: It has been proposed that with continuous administration ofperoxisome proliferators, liver cells are subjected to persistent oxidative stress resulting from marked proliferation of peroxisomes and a differential increase in the levels of H2O2 producing and degrading enzymes.
Abstract: Peroxisome proliferators are hepatocarcinogens in rats and mice. Chronic administration of these compounds results in the development of altered areas and neoplastic nodules followed by hepatocellu...

Journal ArticleDOI
TL;DR: Lead in bone can be measured in vivo using gamma-rays from a 109Cd source to excite lead K X-rays to produce a determination of the concentration of lead in bone mineral that is accurate and insensitive to variations in measurement or bone geometry.
Abstract: Lead in bone can be measured in vivo using gamma-rays from a 109Cd source to excite lead K X-rays. Normalization of lead X-ray amplitudes to that of the elastically backscattered 88 keV gamma-rays produces a determination of the concentration of lead in bone mineral that is accurate and insensitive to variations in measurement or bone geometry. For in vivo tibia measurements, a typical precision (1 SD) of +/- 5 micrograms lead (g bone mineral)-1 is achieved for an effective dose equivalent of 2.1 microSv. Measurement can be made of any superficial bone site, but precision will vary approximately as the inverse of the square root of the mass of bone mineral sampled. The apparatus required for this technique is readily transportable, and mobile laboratory facilities are easily established.

Journal ArticleDOI
TL;DR: It is demonstrated that low doses of CO produce significant effects on cardiac function during exercise in subjects with coronary artery disease and a significant dose-response relationship was found for the individual differences in the time to ST end point and angina for the pre- versus postexposure exercise tests at the three carboxyhemoglobin levels.
Abstract: The purpose of this study was to determine whether low doses of carbon monoxide (CO) exacerbate myocardial ischemia during a progressive exercise test. The effect of CO exposure was evaluated using the objective measure of time to development of electrocardiographic changes indicative of ischemia and the subjective measure of time to onset of angina. Sixty-three male subjects (41-75 years) with well-documented coronary artery disease, who had exertional angina pectoris and ischemic ST-segment changes in their electrocardiograms, were studied. Results from three randomized, double-blind test visits (room air, low and high CO) were compared. The effect of CO exposure was determined from the percent difference in the end points obtained on exercise tests performed before and after a 1-hr exposure to room air or CO. The exposures resulted in postexercise carboxyhemoglobin (COHb) levels of 0.6% +/- 0.3%, 2.0% +/- 0.1%, and 3.9% +/- 0.1%. The results obtained on the 2%-COHb day and 3.9%-COHb day were compared to those on the room air day. There were 5.1% (p = 0.01) and 12.1% (p less than or equal to 0.0001) decreases in the time to development of ischemic ST-segment changes after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. In addition, there were 4.2% (p = 0.027) and 7.1% (p = 0.002) decreases in time to the onset of angina after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. A significant dose-response relationship was found for the individual differences in the time to ST end point and angina for the pre- versus postexposure exercise tests at the three carboxyhemoglobin levels. These findings demonstrate that low doses of CO produce significant effects on cardiac function during exercise in subjects with coronary artery disease.

Journal ArticleDOI
TL;DR: The priority-based assessment of food additives (PAFA) is a database maintained by the U.S. Food and Drug Administration Center for Food Safety and Applied Nutrition that contains extensive administrative, chemical, and toxicological information on 1685 regulated direct food additives.
Abstract: The priority-based assessment of food additives (PAFA) is a database maintained by the U.S. Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition. PAFA contains extensive administrative, chemical, and toxicological information on 1685 regulated direct food additives. The database also has limited administrative and chemical information on an additional 1236 direct additives. The total 2921 substances represent everything added to food in the United States. PAFA contains up to 150 different kinds of information about each chemical. Administrative and chemical information includes Chemical Abstracts Service Registry numbers, Code of Federal Regulations citations, the annual usage and estimated daily U.S. human consumption, the Joint Committee on Food Additives Allowable Daily Intakes, the FDA Redbook structure categories of the chemicals, and their technical effects. Toxicology information shows the type of studies done for each chemical, the species of animals tested, the toxicological effects observed and the sites where they were seen, the lowest doses that cause a toxicological effect in each study, a source citation, and other types of related information.

Journal ArticleDOI
TL;DR: Cancer incidence and mortality in a cohort of 6000 nonsmoking California Seventh-Day Adventists were monitored for a 6-year period, and relationships with long-term cumulative ambient air pollution were observed.
Abstract: Cancer incidence and mortality in a cohort of 6000 nonsmoking California Seventh-Day Adventists were monitored for a 6-year period, and relationships with long-term cumulative ambient air pollution were observed. Total suspended particulates (TSP) and ozone were measured in terms of numbers of hours in excess of several threshold levels corresponding to national standards as well as mean concentration. For all malignant neoplasms among females, risk increased with increasing exceedance frequencies of all thresholds of TSP except the lowest one, and those increased risks were highly statistically significant. For respiratory cancers, increased risk was associated with only one threshold of ozone, and this result was of borderline significance. Respiratory disease symptoms were assessed in 1977 and again in 1987 using the National Heart, Lung and Blood Institute respiratory symptoms questionnaire on a subcohort of 3914 individuals. Multivariate analyses which adjusted for past and passive smoking and occupational exposures indicated statistically significantly (p less than 0.05) elevated relative risks ranging up to 1.7 for incidence of asthma, definite symptoms of airway obstructive disease, and chronic bronchitis with TSP in excess of all thresholds except the lowest one but not for any thresholds of ozone. A trend association (p = 0.056) was noted between the threshold of 10 pphm ozone and incidence of asthma. These results are presented within the context of standards setting for these constituents of air pollution.