Bone Lead Research Articles

Cumulative lead exposure in community-dwelling adults and fine motor function: Comparing standard and novel tasks in the VA Normative Aging Study

Background and aimsLead exposure in children and occupationally exposed adults has been associated with reduced visuomotor and fine motor function. However, associations in environmentally exposed adults remain relatively unexplored. To address this, we examined the association between cumulative lead exposure—as measured by lead in bone—and performance on the grooved pegboard (GP) manual dexterity task, as well as on handwriting tasks using a novel assessment approach, among men in the VA Normative Aging Study (NAS). MethodsGP testing was done with 362 NAS participants, and handwriting assessment with 328, who also had tibia and patella lead measurements made with K-X-Ray Fluorescence (KXRF). GP scores were time (s) to complete the task with the dominant hand. The handwriting assessment approach assessed the production of signature and cursive lowercase l and m letter samples. Signature and lm task scores reflect consistency in repeated trials. We used linear regression to estimate associations and 95% confidence intervals (CI) with adjustment for age, smoking, education, income and computer experience. A backward elimination algorithm was used in the subset with both GP and handwriting assessment to identify variables predictive of each outcome. ResultsThe mean (SD) participant age was 69.1 (7.2) years; mean patella and tibia concentrations were 25.0 (20.7)μg/g and 19.2 (14.6)μg/g, respectively. In multivariable-adjusted analyses, GP performance was associated with tibia (β per 15μg/g bone=4.66, 95% CI: 1.73, 7.58, p=0.002) and patella (β per 20μg/g=3.93, 95% CI: 1.11, 6.76, p=0.006). In multivariable adjusted models of handwriting production, only the lm-pattern task showed a significant association with tibia (β per 15μg/g bone=1.27, 95% CI: 0.24, 2.29, p=0.015), such that lm pattern production was more stable with increasing lead exposure. GP and handwriting scores were differentially sensitive to education, smoking, computer experience, financial stability, income and alcohol consumption. ConclusionsLong-term cumulative environmental lead exposure was associated with deficits in GP performance, but not handwriting production. Higher lead appeared to be associated with greater consistency on the lm task. Lead sensitivity differences could suggest that lead affects neural processing speed rather than motor function per se, or could result from distinct brain areas involved in the execution of different motor tasks.

Analysis of Trace Elements in Bone by Radioisotope Induced EDXRF

In order to obtain a correlation of lead in bone and osteoporosis and other toxic related disease a study was carried out on bones. Femoral head bone samples obtained from osteoporosis patients were analyzed using Cd109 induced EDXRF consisting of a Si(Li) X-ray detector spectrometer coupled to a PC based Multichannel Analyzer. Besides other trace elements, calcium and strontium were predominantly seen in all samples. Lead was also detected.

Cumulative exposure to lead and cognition in persons with Parkinson's disease

Dementia is an important consequence of Parkinson's disease (PD), with few known modifiable risk factors. Cumulative exposure to lead, at levels experienced in the community, may exacerbate PD-related neural dysfunction, resulting in impaired cognition. Among 101 persons with PD ("cases") and, separately, 50 persons without PD ("controls"), we evaluated cumulative lead exposure, gauged by tibia and patella bone lead concentrations, in relation to cognitive function, assessed using a telephone battery developed and validated in a separate sample of PD patients. We also assessed the interaction between lead and case-control status. After multivariable adjustment, higher tibia bone lead concentration among PD cases was associated with worse performance on all of the individual telephone tests. In particular, tibia lead levels corresponded to significantly worse performance on a telephone analog of the Mini-Mental State Examination and tests of working memory and attention. Moreover, higher tibia bone lead concentration was associated with significantly worse global composite score encompassing all the cognitive tests (P = 0.04). The magnitude of association per standard deviation increment in tibia bone lead level was equivalent to the difference in global scores among controls in our study, who were approximately 7 years apart in age. The tibia lead-cognition association was notably stronger within cases than within controls (P(difference) = 0.06). Patella bone lead concentration was not consistently associated with performance on the tests. These data provide evidence suggesting that cumulative exposure to lead may result in worsened cognition among persons with PD.

BMD, Micro-Architecture Estimation (TBS) and Vertebral Fracture Assessment (VFA) Extracted From a Single DXA Device in Combination With Clinical Risk Factors Improve Significantly the Identification of Women at High Risk of Fracture

BMD, Micro-Architecture Estimation (TBS) and Vertebral Fracture Assessment (VFA) Extracted From a Single DXA Device in Combination With Clinical Risk Factors Improve Significantly the Identification of Women at High Risk of Fracture

Lead Bone Toxicity in Growing Rats Exposed to Chronic Intermittent Hypoxia

Lead chronic intoxication under hypoxic conditions revealed growth retardation in growing rats and damages on femoral and mandibular bones that predispose to fractures. These findings aimed us to investigate if bone material and geometric properties, bone mass in terms of histomorphometry or antioxidant capacity are also impaired in such experimental model. Combined treatments significantly reduced hemimandible cross sectional geometry and intrinsic stiffness (-16% and -34%); tibia and hemimandible bone volume (-45% and -40%) and growth plate cartilage thickness (-19%). These results show a previously unreported toxic effect of lead on mandible however, longer studies should be necessary to evaluate if an adaptation of bone architecture to maintain structural properties may occur and if the oxidative stress can be identified as the primary contributory agent in the pathogenesis of lead poisoning.

The effects of low pre-pregnant lead exposure level on maternal bone turnover during gestation and lactation in mice

To study the effects of low pre-pregnant lead exposure level on the mobilization of lead and calcium in maternal skeleton during gestation and lactation in mice. Seventy Kunming female mice were randomly divided into the lead exposure or control groups, 36 mice were exposed to lead by drinking water (50 mg/L) and 36 mice were exposed to deionized water for 4 weeks. The levels of calcium and lead in blood and femurs were measured on the 1st, 7th and 14th days during gestation and on the 1st,10th and 21st days during lactation with atomic absorption spectrophotometry using a heated graphite atomizer or flame atomic absorption spectrophotometry. As compared with the pre-pregnant, at the end of lactation in exposure group the levels of calcium in blood and bones significantly decreased 18.5% and 17.75%, respectively, the levels of lead in blood significantly increased 65.22% and the levels of lead in bones significantly decreased 28.45% (P < 0.05). There was a significant negative correlation between the blood lead level and the bone lead level during gestation and lactation in exposure group (r = -0.904, P < 0.01). There were significant differences of lead and calcium levels during the gestation and lactation between exposure group and control group (P < 0.05). The lead mobilization in maternal bone occurred during gestation and lactation in mice, which could be accelerated by the low pre-pregnant lead exposure.

Synthesis and Biological Evaluation of Phenyl Substituted 1H‐1,2,4‐Triazoles as Non‐Steroidal Inhibitors of 17β‐Hydroxysteroid Dehydrogenase Type 2

A series of disubstituted-1H-1,2,4-triazole derivatives was synthesized with the aim of developing new non-steroidal inhibitors of 17β-hydroxysteroid dehydrogenase type 2 (17βHSD2) - a novel and attractive target for the treatment of osteoporosis. 17βHSD2 catalyzes the oxidation of the highly active estrogen 17β-estradiol (E2) and androgen testosterone (T) into the weak estrone and androstenedione, respectively. Inhibition of this enzyme will locally in the bone lead to an increase in E2 and T levels, two key players in the maintenance of the balance between bone resorption and bone formation. In this study, a new class of 17βHSD2 inhibitors with a 1H-1,2,4-triazole scaffold was identified; the three best compounds 8b, 8f, and 13a showed moderate 17βHSD2 inhibitory activity and a good selectivity toward 17βHSD1. They could be a useful tool to map the unexplored enzyme active site.

Relation of Cumulative Low-Level Lead Exposure to Depressive and Phobic Anxiety Symptom Scores in Middle-Age and Elderly Women

Background: Different lines of evidence suggest that low-level lead exposure could be a modifiable risk factor for adverse psychological symptoms, but little work has explored this relation.Objective: We assessed whether bone lead—a biomarker of cumulative lead exposure—is associated with depression and anxiety symptoms among middle-age and elderly women.Methods: Participants were 617 Nurses’ Health Study participants with K-shell X-ray fluorescence bone lead measures and who had completed at last one Mental Health Index 5-item scale (MHI-5) and the phobic anxiety scale of the Crown-Crisp Index (CCI) assessment at mean ± SD age of 59 ± 9 years (range, 41–83 years). With exposure expressed as tertiles of bone lead, we analyzed MHI-5 scores as a continuous variable using linear regression and estimated the odds ratio (OR) of a CCI score ≥ 4 using generalized estimating equations.Results: There were no significant associations between lead and either outcome in the full sample, but associations were found among premenopausal women and women who consistently took hormone replacement therapy (HRT) between menopause and bone lead measurement (n = 142). Compared with women in the lowest tertile of tibia lead, those in the highest scored 7.78 points worse [95% confidence interval (CI): –11.73, –3.83] on the MHI-5 (p-trend = 0.0001). The corresponding OR for CCI ≥ 4 was 2.79 (95% CI: 1.02, 7.59; p-trend = 0.05). No consistent associations were found with patella lead.Conclusions: These results provide support for an association of low-level cumulative lead exposure with increased depressive and phobic anxiety symptoms among older women who are premenopausal or who consistently take postmenopausal HRT.

Trace metals and micronutrients in bone tissues of the red fox Vulpes vulpes (L., 1758).

In this study we determined the levels of trace elements (zinc, copper, lead, cadmium and mercury) in three layers of bones of the hip joint (cartilage, compact bone and spongy bone) of 30 red foxes (Vulpes vulpes) from north-western Poland. Concentrations of Cu, Zn, Pb and Cd were determined by atomic absorption spectrophotometry (ICP-AES) in inductively coupled argon plasma using a Perkin-Elmer Optima 2000 DV. Determination of Hg concentration was performed by atomic absorption spectroscopy. In cartilage, compact bone and spongy bone samples from the red fox, median concentrations of the metals studied could be arranged in the following descending series: Zn > Cu > Pb > Cd > Hg, the values ranging from 142 to 0.002 mg/kg dw. There was a significant difference in Cu concentrations, among all the materials analyzed, with much more Cu found in spongy bone than in compact bone. Significant differences were also noted in the case of Hg concentrations in cartilage with compact bone and the spongy bone, and between concentrations of this metal in compact bone and spongy bone. In males, the concentration of Hg in spongy bone was greater than in females. Younger foxes had a higher concentration of this metal in cartilage than adults. The strongest synergistic relationships were observed in spongy bone between the Zn and Cu, Zn and Cd, as well as between Cu and Cd. Statistically significant antagonistic relationships were detected between zinc and lead in compact bone. In addition to monitoring studies conducted on the abiotic environment, an urgent need exists for long-term monitoring of concentrations of heavy metals with long-term effects on living organisms. An important addition is provided by biomonitoring studies on domesticated and free-living mammals, including Canidae.

An interlaboratory comparison of bone lead measurements via K-shell X-ray fluorescence spectrometry: validation against inductively coupled plasma mass spectrometry

(109)Cd-based K-shell X-ray fluorescence spectrometry (hereafter, for brevity, XRF) is used, often in epidemiological studies, to perform non-invasive, in vivo measurements of lead in bone. We conducted the first interlaboratory study of XRF via the circulation of nine goat tibiæ in which the mean lead value ranged from 4.0 µg g(-1) to 55.3 µg g(-1) bone mineral. The test tibiæ were subsequently analyzed via nitric acid digestion followed by lead determination by inductively coupled plasma mass spectrometry (ICP-MS) - along with certified reference materials for bone lead - thus providing measurement traceability to SI units. Analysis of dried bone for lead via nitric acid digestion and ICP-MS yields mass fraction data in units of µg g(-1) dry weight. The mean bone lead value based on ICP-MS analysis ranged from 1.8 µg g(-1) to 35.8 µg g(-1) dry weight. For comparison purposes, XRF-measured Pb values (µg g(-1) bone mineral) were converted into the ICP-MS-measured units (µg g(-1)dry weight bone) by multiplying the former by the average ash fraction from the nine tibiæ. Eight of the XRF systems did not yield a significant bias for any of the nine tibiæ; one system was biased for one of the tibiæ; two systems were biased for two tibiæ; one system was biased for four tibiæ; two systems (813-1 and 804-2) were biased for five tibiæ and one system (801-1) was biased for six of the nine tibiæ. Average bias for the systems (under those particular operating conditions) that were biased for the majority of samples ranged from -2.6 µg g(-1) (-15.7%) to 5.1 µg g(-1) (30.7%) dry weight bone. All participants now have the ICP-MS data, allowing any corrective actions deemed necessary to be implemented. The ICP-MS data, however, indicated that the lead mass fraction varied considerably with the sampling location within the tibiæ, to the extent of exceeding XRF variability for the higher lead values. Material heterogeneity is an unavoidable reality of measuring lead in bone.

Statistical and Mathematical Concepts and Principles Applicable to Uncertainty Calculations for the Measurement of In Vivo Bone Lead by 109Cd K X Ray Fluorescence

This work discusses the statistical and mathematical concepts and principles applicable to in vivo 109Cd K X Ray Fluorescence measurements ( 109 Cd KXRF) of lead in human bone. The primary aim of this paper is to examine divergent views about the quantitative methods applied to estimate in vivo bone lead concentrations and their uncertainty when using the 109 Cd KXRF technique. The emphasis is on the potential effect of covariance between quantities of interest on the result of an in vivo measurement of bone lead by 109 Cd KXRF, a question which has received little attention in view of the long standing problem of why the average measurement uncertainty is less than the standard deviation of repeated measurements.

Nonlinearity in the relationship between bone lead concentrations and CBLI for lead smelter employees

494 smelter employees from New Brunswick participated in a bone lead survey conducted by McMaster University in 2008, using the four element "clover-leaf" geometry germanium detector system. The employees were measured at two different bone sites, tibia and calcaneus, each measurement lasting 30 minutes. Scattered photons, including Pb X-rays, were collected by the germanium detectors located behind the ¹⁰⁹Cd source. A strong positive correlation was observed between tibia and calcaneus lead concentrations. Having been provided with blood lead levels, a cumulative blood lead index (CBLI) was generated. The employees were classified into four groups based on their date of hire, and their CBLI levels were compared to their tibia and calcaneus lead concentrations in the different groups. The slopes of bone Pb versus CBLI varied amongst groups, with those hired earliest showing the steepest slopes. This could be taken to imply a non-linearity in the uptake of Pb by bone from blood. In this paper, the association of the bone lead concentrations versus CBLI has been expressed by a polynomial function for the whole group of employees.

Study of lead accumulation in bones of Wistar rats by X-ray fluorescence analysis: aging effect

The accumulation of lead in several bones of Wistar rats with time was determined and compared for the different types of bones. Two groups were studied: a control group (n = 20), not exposed to lead and a contaminated group (n = 30), exposed to lead from birth, first indirectly through mother's milk, and then directly through a diet containing lead acetate in drinking water (0.2%). Rats age ranged from 1 to 11 months, with approximately 1 month intervals and each of the collections had 3 contaminated rats and 2 control rats. Iliac, femur, tibia-fibula and skull have been analysed by Energy Dispersive X-ray Fluorescence Technique (EDXRF). Samples of formaldehyde used to preserve the bone tissues were also analysed by Electrothermal Atomic Absorption (ETAAS), showing that there was no significant loss of lead from the tissue to the preservative. The bones mean lead concentration of exposed rats range from 100 to 300 μg g(-1) while control rats never exceeded 10 μg g(-1). Mean bone lead concentrations were compared and the concentrations were higher in iliac, femur and tibia-fibula and after that skull. However, of all the concentrations in the different collections, only those in the skull were statistically significantly different (p < 0.05) from the other types of bones. Analysis of a radar chart also allowed us to say that these differences tend to diminish with age. The Spearman correlation test applied to mean lead concentrations showed strong and very strong positive correlations between all different types of bones. This test also showed that mean lead concentrations in bones are negatively correlated with the age of the animals. This correlation is strong in iliac and femur and very strong in tibia-fibula and skull. It was also shown that the decrease of lead accumulation with age is made by three plateaus of accumulation, which coincide, in all analysed bones, between 2nd-3rd and 9th-10th months.

Decreased blood lead levels after calcitriol treatment in hemodialysis patients with secondary hyperparathyroidism

ObjectiveSecondary hyperparathyroidism (SHP) is characterized by high bone turnover, which may, in turn, result in increased release of lead from bone stores. This study investigated the effects of intravenous calcitriol on blood lead (BL) levels in patients with SHP. MethodsIntravenous calcitriol therapy was administered for 16wk to 28 patients who were on maintenance hemodialysis (HD) and had intact parathyroid hormone (iPTH) plasma levels of >300pg/mL. Blood was drawn at baseline and every 4wk for 16wk to determine the levels of iPTH; bone remodeling markers, including bone-specific alkaline phosphatase (bAP) and type 5b tartrate-resistant acid phosphatase (TRAP); and BL. ResultsOf the 28 patients, 25 responded to calcitriol therapy; they exhibited significant decrements in serum iPTH levels by the end of 4wk of therapy and thereafter. After 16wk of therapy, these patients had significant reductions in serum iPTH levels (p<0.01) and significant and parallel decreases in the levels of bAP (p<0.01), TRAP (p<0.01), and BL (p<0.01). Further analysis showed a significant positive correlation between the levels of BL and serum iPTH (r=0.34, p<0.01) and BL and serum TRAP (r=0.22, p<0.05). However, there was no significant correlation between the levels of BL and serum bAP. ConclusionElevated levels of BL and serum bone remodeling markers, which are common features of SHP, can be effectively suppressed by calcitriol therapy. This indicates that hyperparathyroidism not only accelerates bone remodeling but may also enhance bone lead mobilization in patients on maintenance HD.

RELATION OF CHRONIC ENVIRONMENTAL LEAD EXPOSURE TO DEPRESSION AND ANXIETY SYMPTOMS IN OLDER WOMEN

Background and Aims: Environmental lead exposure has been associated with adverse cardiovascular and cognitive outcomes, which are themselves correlated with psychological symptoms. Yet few studies have examined links between lead exposure and psychological symptoms. We explored the association between bone lead—a biomarker of cumulative lead exposure—and depression and anxiety symptoms among older women. Methods: We measured patella and tibia bone lead by K-X-Ray-Fluorescence, and obtained repeated measures of depression and anxiety symptoms using the Mental Health Index 5-item subscale (MHI-5) and Crown-Crisp Index phobic anxiety scale (CCI) in 615 women in the Nurses Health Study. We analyzed MHI scores as a continuous variable using linear regression and estimated the odds of a CCI score ≥4 using generalized estimating equations, in both cases accounting for correlation between repeated outcomes (MHI: 3; CCI: 2) and adjusting for potential confounders. Results: The average age of participants was 61 (sd=6) years at the time of bone lead measurement. While tibia lead was associated with moderately worse MHI-5 and CCI scores among all women, results were much stronger among women who, at bone lead measurement, were premenopausal or had been consistently on hormone replacement therapy (HRT) since menopause. In these analyses, women in the highest tibia lead tertile scored 8.16 points worse (95% CI: -11.60, -4.72; p-trend&lt;0.0001) on the MHI-5 than women in the lowest tertile, and had increased odds of high phobic anxiety (CCI ≥4; OR=2.41; 95% CI: 1.06-5.50; p-trend=0.04). We found no relation of patella lead to depression and anxiety symptoms. Conclusions: Our results support an association of cumulative environmental lead exposure with increased risk of depression and anxiety symptoms among older women. Weaker results when including women not consistently on HRT after menopause may be an artifact of increased error in estimating cumulative exposure with bone lead among these women.

LEAD EXPOSURE ALTERS NEURAL MECHANISMS OF LEARNING: A PILOT STUDY OF FEAR-POTENTIATED STARTLE IN ELDERLY MEN

Background and Aims: Physiologically-based indicators of neurological function could provide mechanistic insight into toxicant actions on the brain, and perhaps prove a more objective and sensitive measure of such effects than other methods. We explored the effects of lead exposure on classical conditioning of the acoustic startle reflex (ASR)—a simple form of learning in the brain—in a population of elderly men. Methods: Fifty-one men from the Normative Aging Study (NAS) with patella and tibia bone lead measurements made with K-XRay-Fluorescence participated in a fear-conditioning protocol. One of two visual conditioned stimuli (CS) on a computer was paired with a mild finger shock. Eye-blink responses (electromyogram) to a loud noise burst were recorded with surface electrodes. Conditioning was indexed as the difference in z-scored eye-blink responses to noise bursts delivered in the presence of the paired and non-paired CS after the pairing process—when no shocks were delivered. Results: The mean age of the men was 76 years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.4μg/g bone (sd=12.2; range=5-63). In unadjusted analyses among 37 men with valid eyeblink responses at the end of the protocol, conditioning was 0.56sd less (95% CI:-1.02, -0.11; p=0.02) per 20 μg/g patella lead (the interquartile range of the parent NAS population). Tibia results were similar. Adjusting for age weakened associations only slightly, but there was no association between age itself and conditioning. Baseline startle amplitude was associated with age (β=-26.577μV per year; 95% CI:-47.67, -5.48; p=0.0137), but not with conditioning. Conclusions: In elderly men patella bone lead concentrations, a marker of cumulative lead exposure, predicted learning in a fear-conditioning startle paradigm. While the data are taken from a relatively small sample, this initial exploration offers the possibility that the ASR may provide a new paradigm to explore the effects of neurotoxicant exposure.

MATERNAL LEAD LEVELS AT ONE-MONTH POSTPARTUM IN RELATION TO DIETARY FOOD GROUP INTAKE

Background and Aims: Increasing evidence suggests that dietary intake of fiber and micronutrients such as calcium, iron and vitamin C may interact with lead absorption, deposition, and excretion; however, there is limited information on the association with specific food groups so we assessed relationships between their intake over the course of pregnancy and lead levels in blood, bone, and breast milk at one-month postpartum in a cohort of 613 lactating women in Mexico City. Methods: Maternal dietary intake was assessed using a semi-quantitative food frequency questionnaire of 120 foods that were grouped into 8 groups: dairy products, legumes, fruits and vegetables, whole grain cereals, refined cereals, all-meats, fats and oils and typical Mexican foods. Blood and breast milk were analyzed for lead by ICP-MS and maternal bone lead was estimated by K-x-ray fluorescence (KXRF). Results: In a multivariate linear regression model using log-transformed blood and breast milk lead, women in the highest (v. lowest) tertile of intake of whole grain cereals had 0.10□g/dL lower blood lead levels (95% CI: -0.19, -0.01). Women in the highest (v. lowest) tertile intake of fruit and vegetables had lower lead levels in breast milk and tibia bone: -0.21 □g/L (95% CI: -0.42, 0.007) and -1.05□g/g (95% CI: -1.97, -0.12), respectively. Results were adjusted for parity, exclusive or partial breastfeeding, current use of lead-glazed ceramics, hemoglobin, body mass index, dietary energy intake, years of living in Mexico City, education and number of previous pregnancies. We found no association with patella lead levels. Conclusions: Dietary fiber in whole grain cereals may inhibit lead absorption. The lower lead levels associated with higher intake of fruits and vegetables may be related to decreased absorption and/or the impact of Vitamin C, which has been previously reported to increase excretion of lead by acting as a natural chelating agent.

Blood lead levels and cumulative blood lead index (CBLI) as predictors of late neurodevelopment in lead poisoned children

Objective: To find the best lead exposure assessment marker for children.Methods: We recruited 11 children, calculated a cumulative blood lead index (CBLI) for the children, measured their concurrent BLL, assessed their development, and measured their bone lead level.Results: Nine of 11 children had clinically significant neurodevelopment problems. CBLI and current blood lead level, but not the peak lead level, were significantly or marginally negatively associated with the full-scale IQ score.Conclusion: Lead exposure at younger age significantly impacts a child’s later neurodevelopment. CBLI may be a better predictor of neurodevelopment than are current or peak blood lead levels.

Longitudinal Changes in Bone Lead Levels

Bone lead is a cumulative measure of lead exposure that can also be remobilized. We examined repeated measures of bone lead over 11 years to characterize long-term changes and identify predictors of tibia and patella lead stores in an elderly male population. Lead was measured every 3 to 5 years by k-x-ray fluorescence and mixed-effect models with random effects were used to evaluate change over time. A total of 554 participants provided up to four bone lead measurements. Final models predicted a -1.4% annual decline (95% CI: -2.2 to -0.7) for tibia lead and piecewise linear model for patella with an initial decline of 5.1% per year (95% CI: -6.2 to -3.9) during the first 4.6 years but no significant change thereafter (-0.4% [95% CI: -2.4 to 1.7]). These results suggest that bone lead half-life may be longer than previously reported.

A miniature X‐ray tube approach to measuring lead in bone using L‐XRF

AbstractUsing a miniature X‐ray tube and silicon PiN diode detector, an approach to measuring lead (Pb) in bone phantoms was tested. The X‐ray tube was used to excite L‐line X‐ray fluorescence (L‐XRF) of lead in bone phantoms. The bone phantoms were made from plaster of Paris and dosed with varying quantities of lead. Phantoms were made in two sets with different shapes to model different bone surfaces. One set of bone phantoms was circular in cross‐section (2.5‐cm diameter), the other square in cross‐section (2.2 cm × 2.2 cm). Using an irradiation time of 180 s (real time), five trials were run for each bone phantom. Analysis was performed for both Lα and Lβ lead X‐rays. Based on these calibration trials, (3σ0/slope) minimum detection limits of 7.4 ± 0.3 µg Pb g−1 (circular cross‐section) and 8.6 ± 0.6 µg Pb g−1 (square cross‐section) were determined for the bare bone phantoms. To simulate a more realistic in vivo scenario with soft tissue overlying bone, further trials were performed with a resin material placed between the experimental system and the bone phantom. For the square cross‐section bone phantoms, a layer of resin with a thickness of 1.2 mm was used, and a minimum detection limit of 17 ± 3 µg Pb g−1 determined. For the circular cross‐section phantoms, a layer of resin with an average thickness of 2.7 mm was used. From these, a more realistic minimum detection limit for in vivo applications (43 ± 7 µg Pb g−1) was determined. Copyright © 2011 John Wiley &amp; Sons, Ltd.