Environmental Lead Contamination Research Articles

Blood Lead Monitoring in the General Italian Population

Blood lead (B-Pb) levels were determined in 1978-1979, 1980-1981, and 1985-1986 in subjects living in various regions in Italy according to the regulations contained in European Community Directive 77/312 and in Presidential Decree DPR 496/82. From the data obtained, a lowering time trend in median B-Pb levels was evident for subjects from most of the considered Italian regions. In the total samples of male subjects, the median B-Pb levels were 200, 179, and 153 μg/liter in 1978-1979, 1980-1981, and 1985-1986, respectively. In female subjects median B-Pb levels were 140 μg/liter in 1978-1979, 122 μg/liter in 1980-1981, and 100 μg/liter in 1985-1986. A lowering time trend in B-Pb levels has been also observed in the period between 1980 and 1992 in subjects living in the province of Rome. Median B-Pb levels decreased from 190 to 66 μg/liter in males and from 150 to 42 μg/liter in females. During the period of the monitoring program, all over the national territory, the maximum lead content in gasoline has been progressively reduced from 0.635 g/liter in 1980 to 0.15 g/liter in 1991. These data demonstrate how an appropriate measure may succeed in reducing environmental lead contamination, finally resulting in an actual reduction in the level of human exposure. Within the framework of the monitoring program, we studied the associations of blood lead to selected social, environmental, constitutional, and biochemical factors and to clinical parameters. B-Pb was directly related to alcohol consumption, cigarette smoking, and car-driving habits. A positive association was also found between B-Pb and both HDL-cholesterol and γ-glutamyl-transpeptidase, two biochemical indexes of alcohol consumption. Finally, B-Pb was directly and significantly related to both diastolic and systolic blood pressure.

Lead - where are we now and where to from here?

Over the past decade in Australia there has been a resurgence of interest in environmental lead contamination and lead exposure of children. This has resulted in several major initiatives which are having significant effects in reducing children's exposure.

Measurements of environmental lead contamination and human exposure.

The importance of accurate measurements of environmental lead exposure and toxicity is substantiated by analyses documenting the global contamination of the biosphere with industrial lead and the pervasiveness of measurable lead toxicity in human populations. Those data demonstrating environmental lead contamination and toxicity have, in part, led to regulations that limit the amount of lead in some products (e.g., paint, solder, and gasolines) in many industrialized countries. These regulations have resulted in a substantial reduction in some lead discharges to the environment. In spite of these reductions, current environmental lead levels are still often more than 10-fold, and sometimes more than 10,000-fold, higher than natural levels. Further, environmental lead concentrations are expected to remain elevated for a protracted period due to continued emissions of relatively large amounts of industrial lead to the environment and the persistence of contaminant lead in the environment. Discharges of contaminant lead have resulted in increases in organism and human lead levels comparable to increases documented in environmental matrices, as indicated by a recent estimate of the natural level of lead in blood of preindustrial humans (0.016 microgram/dL or 0.8 nM). This estimate is 175-fold lower than average blood lead levels in the United States (2.8 micrograms/dL or 140 nM) and 600-fold lower than the recently (1991) revised Centers for Disease Control (CDC) action level of concern for early toxic effects in children (10 micrograms/dL or 480 nM). The significance of these comparisons to public health is corroborated by numerous studies suggesting that there may be no lower threshold for sublethal toxicity in contemporary (i.e., lead-contaminated) humans. Those data also indicate that environmental lead concentrations that were previously considered innocuous may be deleterious to human health. It is apparent that the extent of sublethal lead toxicity in humans may be best addressed by studies that consider control populations possessing natural (i.e., preindustrial) lead burdens, as well as state-of-the-art, trace-metal-clean techniques and advanced instrumentation. Trace-metal-clean techniques are required to prevent the inadvertent lead contamination of samples, which has plagued many previous analyses of environmental and human lead levels. Advanced instrumentation is required to provide the sensitivity, accuracy, and precision that are needed to quantify the sublethal effects of lead concentrations at environmental levels of exposure. Fortunately, methodologies utilizing these advancements are now capable of addressing many of the important issues (e.g., lead biomolecular speciation, low exposure effects) in environmental and human lead toxicology.

Lead Levels in the Household Environment of Children in 3 High-Risk Communities in California

To assess environmental lead contamination in the household environment of children in high-risk areas of California, three urban locations were surveyed by the California Department of Health Services. Plant, soil, and dust lead levels were measured and a questionnaire was administered. This survey estimates that 3 million homes in California (27%) may have exterior paint lead levels greater than or equal to 5000 ppm, and 1.3 million homes (12%) may have interior paint lead levels greater than or equal to 5000 ppm. The highest concentrations of lead in paint were found on exterior surfaces and, for homes built between 1920 and 1959, on trim. Age of housing was the best predictor of lead in soil and dust; homes built before 1920 were 10 times more likely to have soil lead levels greater than or equal to 500 ppm compared to post-1950 homes. Most of the variability in dust lead levels could not be explained by factors measured in this survey. Sources of lead in the home were more highly correlated with lead dust concentration levels than they were with lead dust loading levels. Households with members reporting a lead job were twice as likely to have high dust lead levels compared to households with no one reporting a lead job. The significant differences in dust lead concentration levels between communities were not reflected in differences in dust lead loading levels. Measuring dust lead loading levels does not appear to be a meaningful sampling method for risk assessment in the context of prioritizing abatement.

Environmental Lead Contamination:

Aims to: familiarize the audience with the potentially serious consequences of exposure to lead and ways of preventing them; facilitate understanding of how massive environmental contamination with lead occurred, and is still happening, with the expectation that this knowledge will be useful in designing strategies to reduce environmental contamination with lead and other toxic substances, in the future; emphasizes the relevance of lead to the subject‐matter of virtually every department in schools of arts and sciences in anticipation that some instructors will incorporate this information into their respective courses to increase their students′ awareness of this topic. Discusses some of the properties and uses of lead and its compounds and then indicates its ubiquitous presence in air, water, soil, dust and food. Considers some effects of exposure to lead and describes some pivotal contributions of various researchers. Explores the role of lead in history, in literature and in art. Briefly surveys occupational exposure to lead in the USA and elsewhere. Describes the reasons for, and consequences of, lead in petrol and in paint. Summarizes an outstanding paper on the topic of values and lead. Finally, based on an examination of a portion of the voluminous literature on lead, offers some opinions on this subject.

The Adverse Effects of Lead

This article considers the problem of widespread environmental lead contamination. Aspects of its epidemiology and toxicology are presented, with emphasis on the effects of low-level lead exposure on people planning parenthood, on the fetus and on young children. Methods of screening for subclinical lead poisoning and dietary treatment and prevention are discussed. Remedial measures for containing and curtailing environmental lead pollution are recommended.

Children's blood lead levels and environmental lead contamination

Children's blood lead levels and environmental lead contamination

Children's blood lead levels and environmental lead contamination

Children's blood lead levels and environmental lead contamination

Children's blood lead levels and environmental lead contamination

Children's blood lead levels and environmental lead contamination

Community prevalence survey of children's blood lead levels and environmental lead contamination in inner Sydney.

To determine the distribution of blood lead levels in preschool children in inner Sydney and identify possible sources of environmental lead. Cross sectional community based prevalence survey of children and the houses in which they live, and a survey of volunteer children. Mort Bay and Summer Hill, residential localities in inner Sydney. Ninety-five children aged 9-48 months able to be identified in a defined geographic area and 63 children aged 9-48 months volunteered by their parents. Concentrations of lead in venous blood of all children and in samples from the home environment of Mort Bay children. Four of the children (2.5%) had blood lead levels > or = 1.21 mumol/L (25 micrograms/dL, the current Australian threshold of concern), 27 (17.1%) had levels > or = 0.72 mumol/L (15 micrograms/dL, the new US threshold for individual intervention) and 80 (50.6%) had levels > or = 0.48 mumol/L (10 micrograms/dL, the new US threshold for community intervention). Blood lead concentrations were significantly correlated with concentrations of lead in "sink" soil (r = 0.555, P = 0.026), play area soil (r = 0.492, P = 0.016) and dust from vacuum cleaners (r = 0.428, P = 0.05), and with age of child (r = -0.182, P = 0.023). The presence of the child during house renovation was a strong predictor of having a blood lead level above 0.72 mumol/L (15 micrograms/dL) (odds ratio, 4.6; 95% confidence interval, 1.8-11.7, P = 0.001). Lead in soil and in household dust in older areas of Sydney is likely to represent a significant health hazard to young children. Many thousands of children may be affected in Sydney and other Australian cities. There is an urgent need for expanded prevalence surveys, public education and the development of strategies for the abatement of lead in urban environments.

Environmental cadmium, lead and nickel contamination: possible relationship between soil and vegetable content

The cadmium, lead and nickel content of soils of four agricultural areas exposed to different degrees of environmental pollution and vegetables grown there were measured by Atomic Absorption Spectrophotometry (AAS). In order to ascertain the possible relationship between the heavy metal content of soils (total and extractable) and of vegetables grown in them, the correlation between the two was calculated. The highest correlation values between metal content of soil and vegetables are these corresponding to nickel: the total metal content in soils and leaves-stems are linear (p<0.01). The extractable metal content of soils and leaves-stems are linear (p<0.1). Therefore, soil seems to be the main contributor to nickel content of plants (leaves-stems). In the case of cadmium a statistically significant linear correlation (p<0.01) was observed between total metal content in soil and in leaves-stems and a negative one between extractable metal content of soils and that of roots-bulbs. For lead a negative correlation was found between extractable metal content of soils and leaves-stems. In any case, the lead content of soils is not the main factor that influences the lead content of vegetables. Anthropogenic and environmental factors play a more important role than the lead in soils in the lead content of vegetables.

In situ evaluation of biological hazards of environmental pollutants: Chapel Hill, NC (U.S.A.), December 5–7, 1988

Introductory Remarks.- In Situ Evaluation of Biological Hazards of Environmental Pollutants.- Industrial and Regulatory Needs.- Toxicological Research and Related Programs Under Superfund.- Biological Assessment and Ecological Risk Assessment: New Tools for Clean-up Decisions at Hazardous Waste Sites.- Field Studies: Aquatic Systems.- Bioassessment Methods for Determining the Hazards of Dredged Material Disposal in the Marine Environment.- Use of Herring Embryos for In Situ and In Vitro Monitoring of Maring Pollution.- New Methods for On-Site Biological Monitoring of Effluent Water Quality.- Micronucleus Test Using Peripheral Red Blood Cells of Amphibian Larvae for Detection of Genotoxic Agents in Freshwater Pollution.- Predicting the Ecological Significance of Exposure to Genotoxic Substances in Aquatic Organisms.- Field Studies: Terrestrial Systems.- Flow Cytometry as a Technique to Monitor the Effects of Environmental Genotoxins on Wildlife Populations.- Developing Comprehensive Field Studies to Identify Subchronic and Chronic Effects of Chemicals on Terrestrial Ecosystems. Ecosystem Health VI.- Earthworm Immunoassays for Evaluating Biological Effects of Exposure to Hazardous Materials.- Sentinel Surveillance Systems.- Analytical Epidemiology in Pet Populations for Environmental Risk Assessment.- Sentinel Animals (Dogs) as Predictors of Childhood Exposure to Environmental Lead Contamination: Observations on Preliminary Results.- Fish Neoplasms Found at High Prevalence in Polluted Waters.- Biological Markers in Animal Sentinels: Laboratory Studies Improve Interpretation of Field Data.- DNA-Carcinogen Adducts in Fish as a Tool for Measuring the Effective Biological Dose of Aquatic Carcinogens.- IN SITU Monitoring of Environmental Clastogens Using Tradescantia-Micronucleus Bioassay.- The Use of Drosophila Melanogaster for In Situ Biomonitoring.- Chemical Etiology of Endemic Diseases: A Global Perspective.- Integration of Data for Effective Problem Solving and Assessment.- Chemical Analysis for Assessment and Evaluation of Environmental Pollutants: Fact or Artifact.- In Situ Toxicological Monitoring: Use in Quantifying Ecological Effects of Toxic Waste.- Integrated Chemical, Pathological and Immunological Studies to Assess Environmental Contamination.- Use of Wildlife for On-Site Evaluation of Bioavailability and Ecotoxicity of Toxic Substances Found in Hazardous Waste Sites.- Relevancy and Future.- Capabilities and Limitations of Approaches to In Situ Ecological Evaluation.

The influence of pH on the incorporation of lead in Pisolithus tinctorius

It is recognized that environmental lead contamination due to various forms of air pollution may cause serious damage to plant forest tree species. Much of this damage may occur in its action upon soil microorganisms, particularly fungi which form mycorrhizal associations with fine roots of forest trees. Of particular concern is the mobility of lead ions into plant roots from soils which have become acidified through the influence of atmospheric acidic deposition. Both the mobility and uptake may be affected by pH. In order to determine the lead uptake and extent of cellular damage within fungal cells, we have studied the ultrastructure of lead-treated Pisolithus tinctorius, a common ecto- mycorrhizal symbiont of pine species. Furthermore, we have employed energy- dispersive x-ray microanalysis (EDX) to determine the localization of lead within cells at pH levels of 4.5, 3.5, and 2.5.Agar cultures of P. tinctorius were used to inoculate defined liquid media adjusted to the three pH levels with 1 N HCl and supplemented with 0, 50 and 100 ppm PbCl2. After growth for 10 days, terminal hyphae were harvested, conventionally fixed for transmission electron microscopy (TEM) with glutaraldehyde and osmium tetroxide, dehydrated in a graded ethanol series, and embedded in an Epon 812/Araldite resin mixture. Ultrathin sections were cut for TEM observations, and semithin sections were prepared for EDX. Sections to be analyzed for lead by means of EDX were unstained.

Use of Epidemiological and Toxicological Observations in Domestic and Wild Animal Populations for Evaluating Human Health Risks

Domesticated and wild animal populations are important resources in evaluating human health risks. Animals not only share man's environment, but some of them are also part of the human food chain. Three examples of monitoring the health of animal populations and using these data in evaluating human health risk were reviewed. A study of horses, cattle and wildlife in a Missouri lead mining and smelting area revealed that horses were sensitive indicators of environmental lead contamination; they developed clinical signs of lead poisoning and died, while other animal species in the same area did not exhibit signs of illness. Although they did not appear ill, cattle in the same area had liver and kidney lead concentrations that were higher than tolerance levels established in England, Wales and Canada. Wildlife such as bullfrogs, muskrats, and greenbacked herons collected downstream from an old lead mining area had significantly higher lead and cadmium levels than either upstream samples or comparable downstream samples collected at a new lead mining area. Some of these data were used in a court trial which resulted in the lead company buying the farmland so that humans and domestic animals would not be exposed. Another study of municipal sludge application on Ohio farms did not reveal excess illness rates for either livestock or humans living on farms receiving the sludge, as compared with those on control farms. However, cattle were more sensitive than humans as early indicators of low level exposure to toxic heavy metals such as cadmium and lead. Also, calves on sludge-receiving farms accumulated cadmium and lead in their kidneys. The National Animal Health Monitoring System (NAHMS), currently in a pilot stage in eight states, is another example of the use of animal populations to evaluate human health risk. Information from NAHMS about zoonotic infections, use of drugs in food producing animals and diseases common to both animals and man, provide a better understanding of human disease. Population-based animal studies are desirable adjuncts to laboratory animal studies in assessing human health risk due to environmental exposure.

Assessment of lead contamination of the general environment through blood lead levels

More than 2000 blood samples were collected at random from full-time middle school teachers in 9 cities of China and analyzed for lead concentration with strict quality assurance procedures. Questionnaries about the smoking habits, alcohol consumption, residence condition, and fuel used at home were filled out by each person, and information about traffic, and lead concentration in different areas of the environment was also collected as far as possible. The result showed that the geometric mean of blood lead levels of teachers in different cities was ranging between 59-82 μg l(-1) among them the lowest levels were found in Nanjing and the highest in Shanghai. The difference between the lowest and the highest value was only 23 μg l(-1). Comparing with the results of WHO/UNEP and CEC projects. The overall geometric average blood level in China is lower than in all the other countries except Japan. It indicates that the lead pollution in the general environment of China was not as severe as in the participating countries of WHO/UNEP and CEC projects. This may be attributed by the following factors: The less automobile triffic, the larger proportion of non-leaded gasoline used and the less canned food consumption. Factors influencing the lead levels in blood were also analyzed and the 'normal value' (95% upper limit) of blood lead was assessed to be 160 μg l(-1).

Monitoring of lead deposition near highway: A ten years study

Ten years ago, a survey of lead contamination near highways started in Belgium. Most of the observations, samplings and analyses were devoted to plant materials and soil. Samples were collected in more than twenty different sites: in rural sites, and in a few urban parks or avenues. The first topic was to survey heavy metals dispersion (Pb, Zn, Cd) and the factors affecting lead contamination of roadside environment. A similar study was performed in urban conditions. The efficiency of an experimental green screen has been followed, for its protection and filtering abilities, during seven consecutives years, and it's still operating.

Lead poisoning in roadside populations of deer mice

Deer mice living adjacent to a major Colorado highway ( 19,800 vehicles/day flow rate) were examined to determine if current levels of lead pollution from automobile exhaust presented a hazard to this species. The level of environmental lead contamination, as measured by lead concentration in surface soil and vegetation, was significantly greater 15 m from highway than in a control site 800 m distant. Bones of roadside mice contained approximately ten times as much lead as did those from the control site. Significant differences were also found between the roadside and control populations in regard to lead accumulation in kidney, liver and brain. Lead poisoning, however, could not be demonstrated in roadside mice. The exposure level required to produce recognisable lead poisoning in captive deer mice was approximately five times greater than that encountered by the wild roadside population.

An overview of the conference on low level lead toxicity.

Alice had come through the looking-glass and had just read an intriguing poem in a book she had found on a table. When she had finished it she said, Somehow it seems to fill my head with ideas-only I don't exactly know what they are! On several occasions during this conference, and many times in the past, I have shared Alice's dilemma. Fortunately for most of us here, this is not our first conference on the toxicity of lead, and it becomes increasingly less difficult to place pertinent ideas and data into perspective. We have really come a very long way in our understanding of low-level lead toxicity. How many conferences, symposia, books, review and research articles have there been since that Public Health Service Conference on Environmental Lead Contamination in December of 1965? Our numbers and efforts have expanded daily and data are being generated almost too rapidly for any one to keep up-to-date with it all. As stimulating as this has been for the involved and concerned scientist, the past eight years have not been completely joyous ones; rapid expansion can bring its problems. For some it has been the frustration of keeping patience while new investigators redis-

ENVIRONMENTAL CONTRIBUTION TO BLOOD LEAD LEVELS IN INFANCY

Data have not previously been presented which allow for separation of the relative role of pica from general environmental lead contamination in the development of high blood lead levels in childhood. This study has examined the lead levels in cord and maternal blood and related these values to sources of maternal environmental lead exposure. Infants were then followed prospectively to assess subsequent lead accumulation. Mean maternal blood lead level (n=114) was 1.29 ± .51 μ moles/LRBC and values were significantly influenced (p < .05) by race (Puerto Rican > Black > White), urban location, and age of dwelling, but not by social class or smoking. Mean newborn blood lead level (n=182) was 1.00 ± .51 μ moles/LRBC and values were similarily influenced by maternal race, location and age of dwelling as well as by direct proximity of dwelling to high traffic flow. There was linear relationship between paired maternal and newborn lead levels (r=.687., p < .001). After birth the rise in subsequent blood lead determinations was gradual over the first 18 months of life without evidence of a sudden rise at the age of ambulation. These data suggest that certain environmental factors play a major role in defining a group of infants who are “at risk” for developing high blood lead levels even prior to the development of pica. Exposure to this environment starts in utero.

Lead contamination of environment in Meža valley

From 1896 the lead smelting plant in MeŽa valley, Slovenia, Yugoslavia, is contaminating the environment with lead aerosols. From 1968 a broad ecological and epidemiological study on environmental contamination and human exposure is developed.