Higher Bone Lead Research Articles

Acute and Chronic Lead Exposure in Four Avian Scavenger Species in Switzerland.

Despite irrefutable evidence of its negative impact on animal behaviour and physiology, lethal and sublethal lead poisoning of wildlife is still persistent and widespread. For scavenging birds, ingestion of ammunition, or fragments thereof, is the major exposure route. In this study, we examined the occurrence of lead in four avian scavengers of Switzerland and how it differs between species, regions, and age of the bird. We measured lead concentration in liver and bone of the two main alpine avian scavengers (golden eagle Aquila chrysaetos and bearded vulture Gypaetus barbatus) over the entire area of the Swiss Alps and two of the main avian scavengers occurring in the lowlands of Switzerland (red kite Milvus milvus and common raven Corvus corax). Of those four species, only the bearded vulture is an obligate scavenger. We found that lead burdens in the two alpine avian scavengers were higher than those found for the same species elsewhere in Europe or North America and reached levels compatible with acute poisoning, whereas lead burdens of the two lowland avian scavengers seemed to be lower. Several golden eagles, but only one red kite with abnormally high bone lead concentrations were found. In all four species, a substantial proportion of birds had elevated levels which presumably represent recent (liver lead levels) or past (bone lead levels) uptake of sublethal doses of lead.

The frequency distribution of lead concentration in feathers, blood, bone, kidney and liver of golden eagles Aquila chrysaetos: insights into the modes of uptake

Several cases of acute lead poisoning of golden eagles Aquila chrysaetos have been documented in the Alps. The question, however, remains how often golden eagles take up lead (once, chronically or episodically) and whether this uptake is in fatal or sublethal amounts. We approached this question by examining the level and frequency distribution of lead concentration in different tissues and in three segments of flight feathers in 41 golden eagles found dead, injured or moribund in the Swiss Alps. The frequency distribution of lead concentration in the blood, liver, kidney, wing coverts and shaft of flight feathers were all right-skewed. The highest values in blood, kidney and liver reached levels typical for acute fatal poisoning. In contrast, the frequency distribution of lead in bones was more symmetrical, but 71 % had bone lead concentrations >10 µg/g, which are considered elevated, and 29 % >20 µg/g, values often observed in cases of lethal poisoning. In 22 % of individuals, only one segment of a flight feather had a high lead concentration, while the other two segments had a low concentration. These findings indicate an episodic intake of lead of various amounts that may be immediately fatal (generating high blood levels) or sublethal. The patterns of lead in flight feathers and in bone suggest a repeated sublethal lead intake by the same individual. Such an episodic lead uptake seems only possible through ingestion of lead particles from carcasses or offal left behind by hunters. This also constitutes a risk to other scavengers, notably to the bearded vulture Gypaetus barbatus for which several high bone lead values have been found.

Cumulative Lead Exposure, HFE Polymorphism and QTc and QRSc intervals

Background: We previously reported an association between higher bone lead—a biomarker of cumulative lead exposure—and longer heart rate-corrected QT interval (QTc) among non-occupationally exposed...

Effect of Calcium Supplementation on Blood Lead Levels in Pregnancy: A Randomized Placebo-Controlled Trial

BackgroundPrenatal lead exposure is associated with deficits in fetal growth and neurodevelopment. Calcium supplementation may attenuate fetal exposure by inhibiting mobilization of maternal bone lead and/or intestinal absorption of ingested lead.ObjectiveOur goal was to evaluate the effect of 1,200 mg dietary calcium supplementation on maternal blood lead levels during pregnancy.MethodsIn a double-blind, randomized, placebo-controlled trial conducted from 2001 through 2003 in Mexico City, we randomly assigned 670 women in their first trimester of pregnancy to ingest calcium (n = 334) or placebo (n = 336). We followed subjects through pregnancy and evaluated the effect of supplementation on maternal blood lead, using an intent-to-treat analysis by a mixed-effects regression model with random intercept, in 557 participants (83%) who completed follow-up. We then conducted as-treated analyses using similar models stratified by treatment compliance.ResultsAdjusting for baseline lead level, age, trimester of pregnancy, and dietary energy and calcium intake, calcium was associated with an average 11% reduction (0.4 μg/dL) in blood lead level relative to placebo (p = 0.004). This reduction was more evident in the second trimester (−14%, p < 0.001) than in the third (−8%, p = 0.107) and was strongest in women who were most compliant (those who consumed ≥ 75% calcium pills; −24%, p < 0.001), had baseline blood lead > 5 μg/dL (−17%, p < 0.01), or reported use of lead-glazed ceramics and high bone lead (−31%, p < 0.01).ConclusionCalcium supplementation was associated with modest reductions in blood lead when administered during pregnancy and may constitute an important secondary prevention effort to reduce circulating maternal lead and, consequently, fetal exposure.

Problems in determination of skeletal lead burden in archaeological samples: an example from the First African Baptist Church population.

Human bone lead content has been demonstrated to be related to socioeconomic status, occupation and other social and environmental correlates. Skeletal tissue samples from 135 individuals from an early nineteenth century Philadelphia cemetery (First African Baptist Church) were studied by electrothermal atomic absorption spectrometry and X-ray fluorescence for lead content. High bone lead levels led to investigation of possible diagenetic effects. These were investigated by several different approaches including distribution of lead within bone by X-ray fluorescence, histological preservation, soil lead concentration and acidity as well as location and depth of burial. Bone lead levels were very high in children, exceeding those of the adult population that were buried in the cemetery, and also those of present day adults. The antemortem age-related increase in bone lead, reported in other studies, was not evidenced in this population. Lead was evenly deposited in areas of taphonomic bone destruction. Synchrotron X-ray fluorescence studies revealed no consistent pattern of lead microdistribution within the bone. Our conclusions are that postmortem diagenesis of lead ion has penetrated these archaeological bones to a degree that makes their original bone lead content irretrievable by any known method. Increased bone porosity is most likely responsible for the very high levels of lead found in bones of newborns and children.

Current Blood Lead Is Associated With Decline in Stature Among Children in Chennai, India

ISEE-743 Objective: High bone lead has been associated with higher bone density in the children. This has been postulated to be due to rapid bone mineralization, which during childhood, is associated with decreased stature. Also animal studies have shown decreased longitudinal bone growth. We tested the hypothesis that higher blood lead is associated with decreased stature. Materials and Methods: Subjects comprised 3- to 7-year-old children (N=756), recruited for a cross-sectional gene-lead neurobehavioral study in Chennai. Blood lead levels (BLL) were analyzed using LeadCare Analyzer instrument (ESA Laboratories). Anthropometric measurements [mid arm circumference (MAC), height, and weight] were taken at the time of blood draw. Covariate information was collected using questionnaires administered to the primary caregiver. Multivariate linear models were used to model blood lead and physical growth. Results: Blood lead was significantly associated with height. After adjusting for age, sex, household income, number of other children, birth weight, and dairy consumption, we found that there was a 1.2-cm decline in height per 5 μg/dL of blood lead (P = 0.006). No association was found between BLL and BMI or MAC. However, blood lead was associated (P = 0.04) with increased BMI among children with hemoglobin levels ranging from 11.6 to 12.4 g/dL (second tertile of hemoglobin). Conclusions: This study suggests that blood lead is associated with decreased height. This could be due to the inhibition of growth hormone and parathyroid hormone-related peptide by lead.

Bone lead in the prehistoric population of Gran Canaria.

The present study determined the lead concentration in bone tissue from 40 prehistoric individuals of Gran Canaria, and in a sample of 19 modern day residents of the Canary Islands. Higher bone lead values were observed in the modern sample (18.65 +/- 12.13 &mgr;g/g dry bone tissue) than in the ancient sample (4.41 +/- 3.45 &mgr;g/g dry bone tissue, P < 0.001). Older individuals showed higher bone lead values than younger individuals, but only in the modern group. The correlation between age and bone lead approached statistical significance (P = 0.058). Low bone lead observed in the prehistoric sample suggests a low lead exposure in prehispanic times in Gran Canaria. Am. J. Hum. Biol. 11:405-410, 1999. Copyright 1999 Wiley-Liss, Inc.

Lead concentration in the bones of the feral pigeons (Columba livia): sources of variation relating to body condition and death.

This paper reports on lead concentrations in the tarsometatarsi of 84 individuals of adult feral pigeons Columba livia found dead or experimentally captured in Bratislava, Slovakia. The interrelationships between lead concentrations and time of death, place of death, body measurements, sex, condition, and plumage phenotype were investigated. Size and shape of pigeons was not correlated with bone lead contamination. Sex and plumage color and pattern were slightly associated with variation in bone lead levels, females and melanic (urban) phenotypes tending to have higher bone lead concentrations than males and blue-bar (wild) individuals. Birds with antibodies to chlamydiae did not contain significantly higher lead concentrations in the tarsometatarsi than birds without antibodies. Concentration of lead in tarsi was significantly higher in birds dying in winter, compared to birds dying at the end of summer. Chronic lead poisoning probably causes mortality in pigeons in winter. The natural stressor, cold weather, has the capability of exacerbating the effects of lead poisoning, and the mortality is due to lead exposure coupled with cold stress.

Bone lead levels and delinquent behavior

Objective. —To evaluate the association between body lead burden and social adjustment. Design. —Retrospective cohort study. Setting. —Public school community. Participants. —From a population of 850 boys in the first grade at public schools, 503 were selected on the basis of a risk scale for antisocial behavior. All of the 850 boys who scored in the upper 30th percentile of the distribution on a self-reported antisocial behavior scale were matched with an equal number drawn by lot from the lower 70% of the distribution. From this sample, 301 students accepted the invitation to participate. Exposure Measure. —K x-ray fluorescence spectroscopy of tibia at subjects' age of 12 years. Main Outcome Measures. —Child Behavior Checklist (CBCL), teachers' and parents' reports, and subjects' self-report of antisocial behavior and delinquency at 7 and 11 years of age. Results. —Subjects, teachers, and parents were blind to the bone lead measurements. At 7 years of age, borderline associations between teachers' aggression, delinquency, and externalizing scores and lead levels were observed after adjustment for covariates. At 11 years of age, parents reported a significant lead-related association with the following CBCL cluster scores: somatic complaints and delinquent, aggressive, internalizing, and externalizing behavior. Teachers reported significant associations of lead with somatic complaints, anxious/depressed behavior, social problems, attention problems, and delinquent, aggressive, internalizing, and externalizing behavior. High-lead subjects reported higher scores in subjects' self-reports of delinquency at 11 years. High-lead subjects were more likely to obtain worse scores on all items of the CBCL during the 4-year period of observation. High bone lead levels were associated with an increased risk of exceeding the clinical score (T>70) for attention, aggression, and delinquency. Conclusion. —Lead exposure is associated with increased risk for antisocial and delinquent behavior, and the effect follows a developmental course. (JAMA. 1996;275:363-369)

Bone Lead Levels and Delinquent Behavior

To evaluate the association between body lead burden and social adjustment.Retrospective cohort study.Public school community.From a population of 850 boys in the first grade at public schools, 503 were selected on the basis of a risk scale for antisocial behavior. All of the 850 boys who scored in the upper 30th percentile of the distribution on a self-reported antisocial behavior scale were matched with an equal number drawn by lot from the lower 70% of the distribution. From this sample, 301 students accepted the invitation to participate. EXPOSURE MEASURE: K x-ray fluorescence spectroscopy of tibia at subjects' age of 12 years.Child Behavior Checklist (CBCL), teachers' and parents' reports, and subjects' self-report of antisocial behavior and delinquency at 7 and 11 years of age.Subjects, teachers, and parents were blind to the bone lead measurements. At 7 years of age, borderline associations between teachers' aggression, delinquency, and externalizing scores and lead levels were observed after adjustment for covariates. At 11 years of age, parents reported a significant lead-related association with the following CBCL cluster scores: somatic complaints and delinquent, aggressive, internalizing, and externalizing behavior. Teachers reported significant associations of lead with somatic complaints, anxious/depressed behavior, social problems, attention problems, and delinquent, aggressive, internalizing, and externalizing behavior. High-lead subjects reported higher scores in subjects' self-reports of delinquency at 11 years. High-lead subjects were more likely to obtain worse scores on all items of the CBCL during the 4-year period of observation. High bone lead levels were associated with an increased risk of exceeding the clinical score (T > 70) for attention, aggression, and delinquency.Lead exposure is associated with increased risk for antisocial and delinquent behavior, and the effect follows a developmental course.

Renal function and hyperfiltration capacity in lead smelter workers with high bone lead.

The study was undertaken to assess whether the changes in urinary excretion of eicosanoids (a decrease of 6-keto-PGF1 alpha and PGF2 and an increase of thromboxane) previously found in lead (Pb) exposed workers may decrease the renal haemodynamic response to an acute oral protein load. The renal haemodynamic response was estimated by determining the capacity of the kidney to increase the glomerular filtration rate (in terms of creatinine clearance) after an acute consumption of cooked red meat (400 g). A cross sectional study was carried out in 76 male Pb workers (age range 30 to 60 years) and 68 controls matched for age, sex, socioeconomic state, general environment (residence), and workshift characteristics. The Pb workers had been exposed to lead on average for 18 (range 6-36) years and showed a threefold higher body burden of Pb than the controls as estimated by in vivo measurements of tibial Pb concentration (Pb-T) (geometric mean 66 v 21 micrograms Pb/g bone mineral). The geometric mean concentrations of Pb in blood (Pb-B) and Pb in urine (Pb-U) were also significantly higher in the Pb group (Pb-B: 430 v 141 micrograms Pb/l; Pb-U: 40 v 7.5 micrograms Pb/g creatinine). These conditions of chronic exposure to Pb did not entail any significant changes in the concentration of blood borne and urinary markers of nephrotoxicity, such as urinary low and high molecular weight plasma derived proteins (beta 2-microglobulin, retinol binding protein, albumin, transferrin), urinary activities of N-acetyl-beta-D-glucosaminidase and kallikrein, and serum concentrations of creatinine, beta 2-microglobulin, urea, and uric acid. All participants also had normal baseline creatinine clearances (> 80 ml/min/1.73 m2) amounting on average to 115.5 in the controls v 121.3 ml/min/1.73 m2 in the Pb group. Both control and Pb exposed workers showed a significant increment in creatinine clearance (on average 15%) after oral protein load suggesting that the previously found changes in secretion of urinary eicosanoids apparently has no deleterious effect on renal haemodynamics in the examined Pb workers. The finding that both baseline and stimulated creatinine clearance rates were not only significantly higher in the Pb workers but also positively correlated with Pb-T, suggests that moderate exposure to Pb may be associated with a slight hyperfiltration state, which has been found to attenuate the age related decline in baseline creatinine clearance by a factor of two. Although the relevance of this effect for the worker's health is unknown, it can be concluded that adverse renal changes are unlikely to occur in most adult male Pb workers when their blood Pb concentration is regularly kept below 700 micrograms Pb/l. One should, however, be cautious in extra-polating this conclusion to the general population because of pre-employment screening of the Pb workers for the absence of renal risk factors.

Lead Levels in Human Tissues from the Franklin Forensic Project

Abstract Elemental analyses of bone samples from members of the 1845 Franklin Arctic Expedition revealed the presence of high levels of lead. Initial studies using inductively coupled plasma atomic emission spectrometry (ICP-AES) on one bone indicated a level of 125 μg/g and prompted a more detailed analysis of lead levels by graphite furnace atomic absorption spectrometry in hair, tissues, and bone from various anatomical regions. Results of lead analysis in 27 bone samples from sailors who succumbed on King William Island in 1848 ranged from 87–223 μg/g. Lead levels in bones taken from Inuit (Eskimo) of the same time period with the same geographical area ranged from 1–14 μg/g suggesting that environmental lead levels were not a contributing factor in the high bone lead levels in the British sailors. This is also confirmed by bone lead in two caribou samples found with one of the British sailors which had a lead level of 2 μg/g. Lead levels in bone of a modern population range from 18–50 μg/g. The presentation will include detailed statistics on lead results of 58 individual bone samples. Explanations for the elevated lead levels in sailors has been attributed to the use of food preserved in crudely soldered tin cans. Examination of tin can residues found at Beechey Island substantiated the possibility of gross lead contamination of food consumed during the course of the three year expedition. The implications of the above data on the ultimate fate of the Franklin Expedition will be discussed.