Showing papers in "Environmental Health Perspectives in 1974"

Aluminum in the environment and human health.

Abstract: The review of over 800 references on aluminum (Al) published since the mid-fifties covers the occurrence of Al in soil, air, water, plants and food products, as well as air and water pollution prob...

Environmental impact of cadmium: a review by the Panel on Hazardous Trace Substances.

Abstract: This report is the result of a review by a Panel on Hazardous Trace Substances, as part of a report to an ad hoc Committee on Environmental Health Research whose chairman was Dr. David Rall, Director of the National Institute of Environmental Health Sciences, NIH.

Review of the health effects of sulfur oxides.

Abstract: The pollution in the air is a complex mixture of chemical substances of varying toxicity of which the sulfur oxides are a principal component. Those components which pose the primary hazards to human health have not yet been fully identified, nor have their respective contributions to human disease been fully determined. Efficient and effective control strategies are dependent upon the identification and understanding of these toxic components. Ultimately, the goal of standard-setting should be the development of composite pollution indices rather than control of individual pollutants. Concentrations of SO(2) in the ambient air twice the current standards are associated with adverse health effects. A considerable body of evidence suggests that there may be discernible human health effects from exposure to concentrations approximating the current standards. There is therefore no basis for relaxation of the present standards for sulfur oxides at this time. Since the scientific basis for this judgment is incomplete, further scientific information will be required either to validate the present standards or to justify alteration of these standards.

Passage of particles through the wall of the gastrointestinal tract.

Abstract: In the normal process of digestion, not only substances in solution are absorbed. Solid, undissolved particles in macrocorpuscular form, are "kneaded" into the mucosa during their passage through the digestive tract. These particles in the micrometer size range pass between the epithelial cells into the subepithelial layer. From here they are transmitted both by the lymph vessels and by the mesenteric veins into the circulation, where they remain for a considerable time. This phenomenon, termed persorption, was investigated in detail.

Tumorigenic effect of fibrous dusts in experimental animals.

Abstract: Fibrous dusts (chrysotile, glass fibers, nemalite, palygorscite, and gypsum) and granular dusts (actinolite, biotite, hematite, pectolite, sanidine, and talcum) were injected intraperitoneally into...

Nutritional factors and susceptibility to lead toxicity.

Abstract: Although the quantities of lead (Pb) to which individuals are exposed vary widely, susceptibility of an individual to the effects of a specific level of exposure is another highly important factor in development of lead toxicity. For example, susceptibility to lead toxicity can be modified by several dietary factors. Low dietary intakes of calcium or iron (20% of recommended levels) substantially increase the toxicity of the same level of lead exposure to rats. In the studies of calcium effect, when calcium was fed to rats at (1/5) of the recommended intake, 12 mug Pb/ml drinking water produced the same degree of toxicity as did 200 mug Pb/ml with a normal calcium diet. The maximal dose for a 10-week period that does not impair heme synthesis or renal function in the rat has been established to be 200 mug Pb/ml drinking water. The role of low calcium diet on increasing susceptibility to lead has been confirmed in several species. Mechanisms explaining the effect of calcium on lead toxicity may be related to absorption of lead from the gastrointestinal tract or renal tubule or to function of the parathyroid. Preliminary histological investigations on the parathyroids of control and lead-treated rats on normal and low calcium diets show no effect of lead. Studies are currently underway to evaluate the lead, calcium and iron contents of the diets of children with normal and elevated concentrations of blood lead.

Association between Lower Level Lead Concentrations and Hyperactivity in Children

Abstract: Hyperactive children were compared with a nonhyperactive control group on two measures that reflect the presence of body lead and on a lead exposure questionnaire. The overall hypothesis that was tested was that a relationship exists between hyperactivity in children and a concommitant condition of increased body lead stores. Operationally, the hypothesis was reduced to a comparison of the hyperactive group and control group on the following measures: (1) blood lead levels; (2) post-penicillamine urine lead levels; (3) scores on a lead exposure questionnaire. The designation hyperactive or nonhyperactive was arrived at by using three different measurements: a doctor's diagnosis; a teacher's rating scale; a parent questionnaire. Hyperactive children had significantly higher values on all three measures than did the controls. More than half the hyperactive children had blood lead levels in the range considered to be raised but not toxic, and 60% of post-penicillamine urine levels were in the "toxic" range. It is concluded that there is an association between hyperactivity and raised lead levels, that a large body-lead burden may exact consequencies that have hitherto been unrealized; that the definition of what is a toxic level for blood lead needs reevaluation and that physicians should look for raised lead levels in children with hyperactivity.

Lead aggravates viral disease and represses the antiviral activity of interferon inducers.

Abstract: Lead acetate was administered continuously in the drinking water to CD–1 male mice beginning at 4 weeks of age. An LD10–20 of the lytic viruses or 300 plaque-forming units of RLV was inoculated int...

Role of airborne lead in increased body burden of lead in Hartford children.

Abstract: The ingestion of airborne lead fallout is the mechanism responsible for increased lead body burdens found in 10 urban Connecticut children. The mean indoor lead levels found in housedust was 11,000...

Lead analysis of house dust: a method for the detection of another source of lead exposure in inner city children.

Abstract: A method has been developed to test the hypothesis that lead-containing house dust is responsible for the elevated levels of lead in blood of inner city children. Dust analyses of smears from the floors, walls, and windowsills in low-income inner city dwellings have shown a median concentration of lead five times as high in suburban homes. It is suggested that lead-containing dust may be one of the most important environmental sources of increased lead exposure in this specific population group.

Epidemiology of gastrointestinal cancer.

Abstract: Some 99,000 new cases of cancer of the colon are expected next year, an incidence rate higher than that for both cancer of the lung and cancer of the breast. Evidence from geographic pathology suggests that some environmental factors play a strong role in its etiology. Data obtained in the 1959 survey of one million people by the American Cancer Society and followed since, has failed to show correlation with any of the large number of factors listed. It is suggested that the etiology is one of multiple factors. The synergistic effect of exposure to asbestos and cigarette smoking in the production of bronchogenic carcinoma is demonstrated by data on cohorts of insulation workers. There was also a modest increase in the number of deaths from gastrointestinal cancer in asbestos workers, but smoking did not seem to act in synergistic fashion at that site, except perhaps in the esophagus. Deaths from cancer occurred almost entirely after a period of 20 years or more from initial exposure. The death rate from cancer tended to increase with duration of exposure, but a distinct rise over the expected was seen in those who had been exposed less than one year to amosite dust.

Studies of Human Lead Metabolism by Use of Stable Isotope Tracers

Abstract: Dynamics of lead metabolism were studied by replacement of a portion of the dietary lead with stable isotope tracers, and maintaining subjects on controlled diets for about 6 months Results for on

Lead-Induced Inclusion Bodies: Composition and Probable Role in Lead Metabolism

Abstract: Lead-induced inclusion bodies in renal tubular cells of rats have been studied in vitro after isolation by differential centrifugation. The inclusion bodies are insoluble in physiological media but may be dissolved in denaturants like 6M urea and sodium deoxycholate. They contain about 40-50 mug of lead/mg protein, but only about 10% of this is tightly bound. They also contain calcium, iron, zinc, copper, and cadmium. The protein is rich in glutamic and aspartic acids, glycine and cystine. When dissolved in 6M urea, the protein migrates as a single band on acrylamide gel electrophoresis and has a molecular weight of 27,500. It is suggested that the inclusion bodies function as an intracellular depot of nondiffusible lead. Further studies have been directed toward finding a free, unaggregated lead-containing protein fraction. Nuclear proteins from kidneys of lead-toxic rats were separated into NaCl-, Tris-, and NaOH-soluble fractions and an insoluble acidic fraction. A quantitatively small lead-containing protein was found in the 0.14M NaCl fraction. Amino acid composition, electrophoretic mobility, molecular weight, and ability to bind lead are similar to those of insoluble inclusion body protein. The possible role of this soluble lead-binding protein in the formation of nuclear inclusion bodies is at present time not certain. These studies do suggest, however, that protein-bound lead in renal tubular cells may be partitioned between insoluble and nondiffusible morphologically discrete inclusion bodies and a soluble, extractable fraction which is presumably diffusable.

New information on lead in dirt and dust as related to the childhood lead problem

Abstract: It has been known for many years that the eating of leaded paint is the prime cause of lead poisoning and elevated blood leads of children living in deteriorated housing. Recently, there has been speculation that children may eat dirt and dust contaminated with lead exhausted from cars and that this amount of ingested lead is sufficient to contribute significantly to the childhood lead problem. This paper reports on a twopart study conducted to evaluate the validity of the dirt-and-dust hypotheses. The first part of the study was made to determine the source of lead in dirt to which children are normally exposed. Dirt samples were taken in old urban areas around 18 painted frame houses and 18 houses of brick construction. Samples also were taken around seven old frame farmhouses remote from traffic. Based on the fact that lead concentrations in the dirt were similar in city and rural yards at corresponding distances from the houses, it is clear that nearly all of the lead in dirt around these houses is due to paint from the houses. Lead antiknock additives are therefore not a significant contributor to the lead content of dirt around houses where children usually play. The second part of the study used a naturally occurring radioactive tracer (210)Pb to determine the relative amounts of dust and other lead-containing materials (e.g., paint) eaten by young children. This tracer is present in very low concentrations in paint and in significantly higher concentrations in fallout dust. Stable lead and (210)Pb were analyzed in fecal material from eight children suspected of having elevated body burdens of lead and ten children living in good housing where lead poisoning is not a problem. The normal children averaged 4 mug Pb/g dry feces, with a range of 2 to 7. Of the eight children suspected of having elevated lead body burdens, two had fecal lead values within the normal range. However, the remaining six were 4 to 400 times as high. Despite these differences in fecal lead between the two groups, the groups were essentially identified in the (210)Pb content of their feces. The "elevated" children averaged 0.040 pCi of (210)Pb dry feces, while the normal group averaged 0.044 pCi/g. The results provide sound evidence that these children suspected of elevated lead body burden were not ingesting dust or air-suspended particulate.

Pathobiological and behavioral effects of lead intoxication in the infant rhesus monkey.

Abstract: When infant rhesus monkeys were exposed to lead via the addition of lead acetate (0.5–9 mg/kg body weight) to their formula or by the consumption of lead particles from lead-based surrogate mothers...

Mycotoxins: toxicity, carcinogenicity, and the influence of various nutritional conditions

Abstract: Toxicologic diseases of man and animals, associated with molds growing on foods, have been recognized for centuries Only in recent years, however, have these mycotoxicoses received the attention of many laboratories and skilled scientists around the world in a broad inter-disciplinary effort This review covers the literature on mycotoxicoses but centers on those about which most is known, particularly the diseases associated with metabolites elaborated by some strains of Aspergilli, Penicillia, Fusaria, Stachybotrys, and Claviceps The ubiquitous nature of the aflatoxins, toxic metabolites produced by Aspergillus flavus, make them important to public health, especially since it is now known that certain areas of endemic liver disease coincide with consumption of aflatoxins and, often, malnutrition The older disease of ergotism, the scourge of Europe for centuries, is considered in detail Alimentary toxic aleukia, which has caused enormous suffering in Russian human and animal populations, is better understood as a result of relatively recent experimental investigations Stachybotryotoxicosis, a disease previously considered to be of significance only to man has now been identified in domestic animalsFinally, Japanese studies have clearly revealed the hepatotoxicity of certain metabolites of Penicillium molds Factors that influence susceptibility to mycotoxins and the hazards they present to man are also reviewed

Hyperactivity: a lead induced behavior disorder

Abstract: Mice were exposed to lead from birth by substituting solutions of lead acetate for the drinking water of their mothers. The suckling mice were thus exposed to lead through their mother's milk and, at weaning, directly through the drinking water. Controls received equal concentrations of sodium acetate. No deaths of offspring or mothers occurred during the first 90 days of exposure. It has been suggested recently that lead exposure may account for some incidences of behavior disorders in children. Levels of motor activity of individual offspring were measured from weaning until 70 days of age in specially designed activity cages. Lead-treated mice were more than three times as active as age-matched or size-matched controls. Treated and control animals were administered drugs currently used in the treatment and diagnosis of hyperactivity in children. All control animals responded as expected to all drugs used in this study. However, lead-treated mice responded paradoxically to d- and l-amphetamine, methylphenidate, and phenobarbital. That is, the CNS stimulants suppressed their hyperactivity while phenobarbital exacerbated the lead-induced hyperactivity. These findings suggest that lead produces an animal model of hyperactivity which may have clinical relevance and which may explain some cases of hyperactivity in children.

Electron microscopical investigation of asbestos fibers.

Abstract: Examination of asbestos fibers by electron microscopical techniques enables the observer to distinguish among the fiber types by morphological and structural characteristics. Chrysotile asbestos fi...

Effect of lead intoxication on the postnatal growth of the rat nervous system.

Abstract: Lead encephalopathy was induced in developing Long-Evans rats by adding lead carbonate (4% w/w) to the diet of nursing mother immediately after delivery. The morphological and biochemical features ...

The uptake of lead by children in differing environments.

Abstract: Balance studies have been performed for lead upon eight healthy children in three different home environments and upon eight children with inborn errors of metabolism in hospital (consuming two different types of synthetic diet). The balances were for 3 days and involved the use of metal-free diapers where indicated. The concentration of lead in all the samples was determined by atomic absorption spectroscopy after suitable sample preparation. In addition, the total population of children under the age of 16 living in a working class area exposed to undue amounts of lead was examined in an attempt to determine whether their mental development had been affected. Blood lead levels, general intelligence, reading ability, and rate of behavior disorder were measured. The results of the balances showed that the mean daily intake of lead in both groups of children was lower than previously recorded figures, being lowest of all in the breastfed infant. The healthy group absorbed a mean value of 53% and retained 18% of the dietary intake and there was no relationship to age or month of the year of study. The children with inborn errors showed a significantly lower percentage absorption of lead. The preliminary results of the population survey showed that distance from the polluting lead source was related to blood lead level, but no relationship could be found between blood lead level and any measure of mental function.

Osmium: An Appraisal of Environmental Exposure

Abstract: In the U.S., the chief source of new osmium is copper refining, where this metal is produced as a byproduct. Probably less than 10% of the osmium in the original copper ore is recovered, and 1000–3...

Animal models of human disease: severe and mild lead encephalopathy in the neonatal rat.

Abstract: Inorganic lead produces cerebral dysfunction and clinically definable encephalopathies in man. To date there have been few studies on the biochemical changes in brain following exposure to inorganic lead. Studies correlating toxicity with behavioral and brain neurochemical changes following lead exposure have been hindered because adult laboratory animals are resistant to the central nervous system effects of lead poisoning. Such studies have been impeded by lack of suitable experimental models until Pentschew and Garro showed that brain lesions develop in neonatal rats when a pregnant rat newly delivered of her litter is placed on a 4% lead carbonate containing diet. Lead passes into the developing sucklings via maternal milk. Lead-poisoned new-borns have pronounced retardation of growth and during the fourth week of ilfe develop the severe signs of lead encephalopathy, namely, extensive histological lesions of the cerebellum, brain edema, and paraplegia. There is an approximate 85-fold increase in the lead concentration of both the cerebellum and cerebral cortex relative to controls, but edema and gross vascular changes are confined to the cerebellum. Ingested lead had little effect on RNA, DNA, and protein concentrations of developing rat cerebellum and cerebral cortex. However, there was a reduction of between 10 and 20% in the DNA content of the cerebellum around 3 weeks of age in the lead-exposed sucklings. This suggests a failure of cell multiplication in this part of the brain.A critical evaluation of this experimental approach indicated that under similar dietary conditions experimental lactating rats eat 30% less food than controls resulting in: (a) sustained loss in body weight of nursing mothers and that (b) offsprings who develop paraplegia and cerebellar damage do so after gaining access to lead containing diet. We have studied mothers' food consumption and body weight changes and blood, milk, and brain lead content; and newborns' body and brain weight changes, blood and brain lead content, and brain serotonin (5HT), norepinephrine (NE), dopamine (DA), and gamma-aminobutyric acid (GABA). We have found that a lactating mother rat eating 5% lead acetate (2.73% Pb) produced milk containing 25 ppm lead. When the mothers' diet is changed at day 16 from 5% PbAc to one containing 25 ppm Pb, and neonates allowed free access to the solid diet, the sucklings still have retarded body growth but do not develop paraplegia or grossly apparent vascular damage of the cerebellum. However, during the fourth week these animals exhibit a less severe form of "encephalopathy" consisting of hyperactivity, tremors, and stereotype behavior. Pair-fed controls coetaneous to experimental groups do not display such activities. There was no change in brain 5HT, GABA, or NE, but a 15-20% decrease in brain DA. Change in DA relative to other monoamines suggests a relationship between CNS dysfunction due to lead and DA metabolism in the brain.The experimental design as discribed provides a model of CNS dysfunction due to lead exposure without debilitating histopathologies. It is possible that our findings on increased motor activity and changes in brain dopamine may correspond to early responses to lead exposure before recognized overt signs of toxicity.

Significance of High Soil Lead Concentrations for Childhood Lead Burdens

Abstract: The lead exposure of children and their mothers has been studied in two towns with mean soil lead contents of 900 and 400 ppm. No significant difference in blood or fecal lead contents was demonstr...

Food exposures to lead.

Abstract: Exposures to lead have emanated from various sources, including food, throughout human history. Occupational and environmental exposures (especially pica) appear to account for much of the identified human disease, however, food-borne exposures deserve further investigation. Lead residues in food can result from: biological uptake from soils into plants consumed by food animals or man, usage of lead arsenate pesticides, inadvertent addition during food processing, and by leaching them improperly glazed pottery used as food storage or dining utensils. Estimates of total dietary exposure should reflect frequency distribution data on lead levels in specific food commodities in relation to the quantities actually ingested by various sample populations to distinguish degrees of risk associated with particular dietary habits. Earlier estimates of average total dietary intake of lead by adults have been reported to range from above 500 mug/day downward with more recent estimates suggesting averages of 200 mug/day or lower. The strengths and weaknesses of these data are discussed along with analytical and sampling considerations. FDA programs related to food surveillance, epidemiology, and toxicological investigation are briefly described.

Inorganic particles in human tissues and their association with neoplastic disease.

Abstract: An increased gastrointestinal cancer risk is associated with occupational exposure to asbestos fiber. Examination of tissues obtained from extrapulmonary organs of exposed workmen demonstrates the ...

Identification and quantitation of asbestos in talc

Abstract: The currently used analytical methods for identification, characterization and quantitation of asbestos fiber in consumer talcum products include polarized light microscopy, x-ray diffraction analysis, transmission electron microscopy with selected area electron diffraction and electron microprobe techniques. Light microscope methods have severe limitations imposed by the ultimate size resolution of the light-optical system. Small particles go unresolved; those marginally resolved may possess optical properties different from those properties cited in the literature; most optical properties, e.g., indices of refraction, are difficult to measure on small particles. In addition to these difficulties, talc fibers often possess optical properties different from those of talc plates, which further confound analysis. Light microscopy is recommended for use only as a preliminary tool on limited, large-sized, samples. Transmission electron microscopy is a good standard technique for visualization of contaminant asbestos fibers. Together with selected area electron diffraction, talc fibers may be easily differentiated from amphibole asbestos fibers on the basis of both morphological and structural characterization. Chrysotile fibers are easily distinguished on this basis as well. The amphibole asbestos minerals require chemical characterization to differentiate among the different fiber types. Probe analysis is mandatory for such fibers. The major drawbacks to electron beam instrumentation for the mineralogical characterization of talcum products are the time and effort required for data acquisition. These techniques do not lend themselves to routine study.X-ray diffraction analysis, utilizing the step-scan method, offers a relatively rapid, quantitative technique for gross fiber analysis. Based on comparison with standard specimens the fiber content of talcs may be quantitatively determined. It is essential to employ a specimen preparation technique which yields homogeneously dispersed particles. Tremolite may be determined at levels as low as 0.10% by weight, chrysotile 0.25%, and anthophyllite at 2.0% by weight occurrence in talc. The variance of these values depends upon many factors, including the mass absorption coefficient of the fiber types as compared to talc and selected diagnostic reflections and their relative intensities. Each of the above techniques is described in detail. A method for routine analysis of consumer talcum products is suggested.

Lead content of foodstuffs.

Abstract: The lead content of a number of foodstuffs, particularly baby fruit juices and milk, is reported. Samples were analyzed in quadruplicate by using an automated Delves cup atomic absorption procedure. A large proportion of the products examined contained significant amounts of lead. Of 256 metal can examined, the contents of 62% contained a lead level of 100 mug/l. or more, 37% contained 200 mug/l. or more and 12% contained 400 mug/l. lead or more. Of products in glass and aluminum containers, only 1% had lead levels in excess of 200 mug/l. Lead levels of contents also correlate with the seam length/volume ratio of the leaded seam can. A survey of bulk milk showed a mean lead level of 40 mug/l. for 270 samples; for canned evaporated milk the mean level was 202 mug/l. These data indicate a potential health hazard.

Follow-up of children overexposed to lead.

Abstract: The purpose of this study is to assess the nature and magnitude of the deleterious health effects of subclinical over-exposure to lead in children. The study stems from concerns about the impact on the health of children in city slums who ingest leaded paint without overt evidence of poisoning and the health implication of rising levels of lead in the environment from automotive emissions. The study sample was derived mainly from a registry of children on whom blood lead determinations had been made by the New York City Department of Health and was supplemented by siblings of the registry cases and children from a lead belt area who had extractions of deciduous teeth in dental clinics. Information was obtained through parental interview, medical records, and psychometric evaluation. The data show that deleterious health effects occur in children who were treated for severe lead poisoning and in children without diagnosed lead poisoning who had elevated blood leads (>/=0.06 mg-%). In the absence of diagnosed lead poisoning or elevated blood leads, excess lead exposure, measured in terms of high levels of lead in teeth, was not associated with deleterious health effects.

Deep sea sedimentation

Abstract: An important problem in the study of microparticles in the marine environment, suspended in the water column or deposited as sediment on the ocean bottom, is the determination of provenance of the ...

Drinking water as a source of lead pollution.

Abstract: Frank lead poisoning was found in some inhabitants of houses in the Scottish Highlands, exposed to soft water and lead-lined drinking water tanks. Further investigations were carried out on the clinical and metabolic effects of lead acquired by drinking soft domestic water from lead plumbing systems in 23 Glasgow households. The lead content of water from cold taps was up to 18 times the upper acceptable limit and was proportional to the amount of lead in the plumbing system. The blood lead of 71 inhabitants of these houses showed a significant positive correlation with water lead content. Delta aminolaevulic acid dehydrase activity, an extremely sensitive indicator of lead exposure, showed a significant negative correlation with water-lead content. Atmospheric lead was within acceptable limits in all but one house and no significant correlation could be found with biochemical measurements. A small number of clinical abnormalities were found but could not be directly attributed to lead toxicity. The results of the study underline the possible danger to health of lead plumbing systems in soft-water regions.