Whole Blood Lead Concentrations Research Articles

Cutaneous Resorption of Lead After External Use of Lead-Containing Ointments in Volunteers with Healthy Skin

Lead-containing ointments are frequently used in anthroposophic medicine. In a prospective, open-label phase 1 study, 33 volunteers at the Ambulatory Clinic for Complementary and Alternative Medicine at the Free University of Berlin, aged 18-65 years, were exposed to 100 g Plumbum metallicum 0.4% ointment (Weleda, Germany) over a 4-week period. The lead-containing ointment was regularly applied to the cubital side of the forearm. Regular measurements of lead concentrations in whole blood, urine, and scalp hair were determined. None of the 33 volunteers showed an increase in lead concentrations in the 3 investigated compartments after 4 and 8 weeks. Blood lead levels (average value) decreased significantly from baseline to the first week (P < 0.05). Average values in the following investigations (weeks 3, 4, and 8) were significantly lower than at baseline (P < 0.05). There was no increase in lead levels in the scalp hair after 8 weeks (P < 0.05). The results show that the commonly prescribed lead-containing ointment Plumbum metallicum 0.4% in humans with an intact skin does not present a toxic risk.

Concentrations of lead in blood, hair and saliva of German children living in three different areas of traffic density

Lead contents in hair, whole blood and saliva were determined for 245 healthy children (121 male, 124 female, age: 8–10 years) from three residential areas of Düsseldorf (North-Rhine-Westphalia, Germany) with different traffic densities. The geometric mean for the lead content in hair was found to be 0.87 μg/g (range: 0.2–9.9 μg/g) for the entire test group. While the levels of lead in hair in the suburban population were significantly lower than in the two city centre populations, no significant difference concerning the lead content in hair could be detected in the latter. The geometric mean for lead concentration in whole blood amounted to 25.0 μg/l (range: 8.0–154 μg/l). There was no significant difference between the sub-groups. The lead concentrations found in saliva were rather low (range: <1.5–47.0 μg/l). Of the values, 89% were below the detection limit of 1.5 μg/l. Due to reduced levels of lead in fuel, the present study exposes that the amount of lead in the children examined has further decreased compared to preceding surveys. The correlation between the lead content in hair and the road traffic density was not corroborated by the findings with regard to amounts of lead found in blood, indicating that residual lead from fuel does not result in a substantial burden of lead found in the whole body. In contrast to levels of lead found in blood, levels of lead found in hair may be influenced more by environmental conditions. Saliva is not a suitable material for biological monitoring with respect to lead exposure in children.

Determination of Normal Blood Concentrations of Lead, Zinc, Copper, and Iron in Hispaniolan Amazon Parrots (Amazona ventralis)

Lead, zinc, copper, and iron toxicities are major concerns affecting both wild and captive avian populations. Reference ranges of blood concentrations of these metals in large numbers of birds with no history of environmental exposure have not been reported. This study reports ranges for whole-blood (lead) or plasma (zinc, copper, and iron) concentrations for lead, zinc, copper, and iron in 45 Hispaniolan Amazon parrots that had minimal environmental exposure to any of these metals. Measurements of plasma zinc, copper, and iron concentrations followed a normal distribution, which resulted in reference ranges (mean ± 2 SD) of 1.25–2.29 ppm, 0.07–0.19 ppm, and 2.25–6.25 ppm, respectively. All whole-blood lead concentrations were below 0.02 ppm, and a reference range could not be determined.

LEAD DETERMINATION IN PAROTID AND SUBMANDIBULAR SALIVAS AND WHOLE BLOOD IN RAT

The effects of lead acetate (100 mg/ kg) after repeated intraperitoneal (ip) injection were examined in parotid and submandibular saliva and blood in rats. Animals were treated with 1, 2, or 3 injections of lead acetate and were sacrificed 1 and 7 d after the last injection. Lead concentrations were determined by flame atomic absorption spectroscopy, in whole blood and in submandibular and parotid salivas. Lead concentrations in submandibular and parotid salivas were determined to be 50% and 22% of whole blood lead concentrations, respectively. Lead concentrations in whole blood and in submandibular and parotid salivas were determined to be significantly different from their respected controls. Submandibular saliva lead concentrations were correlated with whole blood lead concentrations ( r = .78) and parotid saliva lead concentrations were correlated ( r = .93) only on d 1 with respect to whole blood level after the first administration (acute poisoning).

Lead concentrations in human plasma, urine and whole blood.

Blood-lead levels (B-Pb), and to some extent urinary lead (U-Pb), are the most employed measures of lead exposure and risk. However, the small fraction of lead present in plasma (usually below 1% of that in blood) is probably more relevant to lead exposure and toxicity. Nevertheless, the lead content of plasma lead (P-Pb) has only seldom been used, mainly due to analytical limitations, which have now been overcome. We examined P-Pb in occupationally exposed subjects, as well as its relationship with B-Pb and U-Pb. Blood samples were obtained from 145 male workers, 110 of whom were employed in lead work. After a simple dilution of plasma, P-Pb was determined by inductively coupled plasma mass spectrometry. The detection limit was 0.04 microg/l, and the imprecision was 5%. The lead concentration ranges were 0.20-37 microg/l for P-Pb, 0.9-176 microg/l (density adjusted) for U-Pb, and 9-930 microg/l for B-Pb. A close exponential relation was obtained between B-Pb and P-Pb. When B-Pb was plotted versus log P-Pb, a straight line (log P-Pb = 0.00225 x B-Pb - 0.58; r = 0.97) was obtained. Both the relation between U-Pb and P-Pb and that between U-Pb and B-Pb showed a large scattering (r = 0.78 in both cases). The relation to B-Pb appeared to be exponential, while that to P-Pb appeared to be linear. The low detection limit and good precision of P-Pb determinations make it possible to use P-Pb in assessments of lead exposure and risk. Furthermore, in relative terms, P-Pb is a more sensitive measure than B-Pb, especially at high lead levels. This development is of importance for studies of exposure, possibly also for studies of risks.

Difficulties in evaluating abnormal lead screening results in children.

This report chronicles efforts to provide follow-up care for children with abnormal whole blood lead concentrations using the 1991 Centers for Disease Control and Prevention (CDC) guidelines in the Family Health Center at Shadyside Hospital in Pittsburgh. An automated surveillance module found all children with abnormal lead concentrations obtained between January 1994 and July 1995 and singled out children who were overdue for follow-up. Automated physician reminders and nursing case management were used to improve care and documentation. Longitudinal case summaries were used to evaluate care. All 99 children with a lead concentration of 10 micrograms/dL or greater had a documented follow-up plan. Twenty-nine children (47 percent) who had a lead concentration of 10 to 14 micrograms/dL, 23 (100 percent) who had a lead concentration of 15 to 19 micrograms/dL, and 8 (100 percent) who had a lead concentration of 20 micrograms/dL or greater had at least one follow-up lead concentration measurement by the end of the data collection in July 1995. Follow-up was incomplete in more than 70 percent of children. Nineteen children (19 percent) with initially abnormal lead concentrations had follow-up testing with persistently normal results. The yearly cost of follow-up was $15,888, with only 7 children requiring county health environmental intervention. The nurse-centered, computer-aided system improved follow-up care of children with abnormal lead concentrations, but most patients still did not receive mandated follow-up testing because of logistic obstacles. The effort and cost associated with CDC-mandated follow-up of children with lead concentrations between 10 and 19 micrograms/dL provides no apparent benefit and might detract from the care of children at higher risk.

The determination of lead in whole blood by laser enhanced ionization using a combination of electrothermal vaporizer and flame

A system for electrothermal vaporization — laser enhanced ionization spectrometry (ETV-LEIS), developed in this laboratory, was used for the determination of lead concentrations in whole blood. Blood standards from the Centers for Disease Control (CDC) and the National Institute of Standards and Technology (NIST) were diluted 21:1 with ultrapure water and analyzed. Good agreement was found between the CDC and NIST standards. A linear analytical curve was obtained with a detection limit (3σ) of 8.9 × 10 −3 μg dl −1 (890 fg absolute) for lead in whole blood. This compares favorably with other current methods for blood-lead determinations including isotope dilution inductively coupled mass spectrometry (ID-ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS).

Determination of copper, lead and cadmium in whole blood by stripping voltammetry with the use of graphite electrodes

The problem with toxic metal ion determination in blood is the adsorption of organic compounds on the electrode surface and the formation of complexes between metal ions and organic constituents of blood. This is the reason why usually preliminary acid digestion or other sample pretreatment is used. Two kinds of electrodes have been used: “Ultra-Trace Electrode”, made from impregnated graphite (I), and thick film graphite disposable electrodes (II). The analysis of whole blood with different sample preparation methods shows, that chemical digestion is not necessary for the analysis. Electrochemical two-stage sample preparation provides the possibility for analysing whole blood with the mentioned electrodes. Thick film disposable electrodes are less sensitive to the interference of organic constituents of blood. These electrodes give the possibility to determine total cadmium, lead and copper concentration in whole blood without special sample pretreatment. The application of “Ultra-Trace Electrode” for blood analysis is possible only after preliminary pretreatment of blood by chemical digestion or electrochemical sample preparation.

The neurobehavioural toxicology and teratology of lead

Lead has been used by man since antiquity, and its detrimental health effects are well known for centuries. Inorganic lead enters the body by way of inhalation or ingestion; uptake through the gastrointestinal tract is the more important route of exposure. Absorption is better in infants than in adults. Lead-concentration in whole blood (PbB), normally expressed as µg/1 or µmol/1, is a representative marker of current lead exposure, whereas tooth lead concentrations have also been used as markers of past exposure (Needleman et al. 1979; Winneke et al. 1983). Both placental transfer and transfer across the blood-brain barrier occur easily in the developing brain, so that prenatal exposure as well as CNS-involvement are possible. Lead serves no known physiological function. Almost all organs or organ systems are potential targets for lead:depending on the duration and degree of exposure, diverse biological effects have been described, the more critical of which are those on heme biosynthesis, erythropoiesis, and the nervous system.

Effects of Lead Exposure on Neurophysiological Parameters

To clarify the chronic effect of lead exposure on the central and peripheral nervous systems (CNS and PNS), we performed neurophysiological tests on 41 lead-exposed male workers. Unexposed workers (controls, N = 39) were examined for auditory brain stem response (ABR), and their ABR parameters were compared with those of 15 lead-exposed workers age-matched to the controls. Neurophysiological tests included those of motor and sensory nerve conduction velocity of the radial nerve (MCV, SCVwa and SCVfw), electroretinograms, pattern reversal visual evoked potential (VEP), ABR, and short-latency somatosensory evoked potentials (SLSEP). Neurophysiological parameters were analyzed by regression analysis [independent parameters: age, exposure duration, and current and time-weighted average lead concentration in whole blood (PbB and TWA-PbB)]. ABR parameters were also tested by Student"s t test. Significant negative correlations were found between radial MCV and TWA-PbB and SCVwa and PbB, while significant positive correlations were found between the latency of component N145 of VEP and exposure duration and between the latency of component N20 of SLSEP and PbB. The mean of interpeak latency between component III and V of ABR of 15 lead-exposed workers was significantly prolonged compared with that of the control group. These results suggested that lead exposure has a greater effect on the conduction function in the PNS than in that of the CNS in somatosensory and auditory pathways, and inversely in visual pathway.

Alcohol consumption and other lifestyle factors: avoidable sources of excess lead exposure.

Lead concentration in whole blood of a representative sample of 471 subjects aged 20 to 74 years and living in Basle was determined in 1989/90 by flame atomic absorption spectrophotometry. The participants in the cross-sectional study filled in a questionnaire on demographic factors, nutrition and drinking habits. The age-adjusted geometrical mean blood lead level was 0.38 +/- 0.19 mumol/litre of whole blood for males, and 0.29 +/- 0.17 mumol/litre for females. The average lead burden was about 30% below the mean concentration found in a comparable population in Western Switzerland five years earlier. Lead emissions in Switzerland decreased by about 40% from 1984 to 1990 through restriction of lead in petrol. This offers the most plausible explanation for the low blood lead levels found in Basle. Sex, age, occupation (employment in painting or printing, construction or the metal processing industry), smoking and alcohol intake (especially wine consumption) were identified as independent blood lead predictors in a multiple linear regression analysis. Participants who consumed alcohol daily had blood lead concentrations on average 12% higher than those of abstinent subjects. Regular smokers had an unconfounded average blood lead level 8% above that of people who never smoked. Place of residence and hourly frequency of cars in that area were not identified as independent predictors in the model. The analysis of 99 different wines on the market in Basle showed an average lead concentration of 50 +/- 17 micrograms/litre wine. Compared to an estimated 25 micrograms daily nutritional intake of lead in Switzerland the value appeared to be high.(ABSTRACT TRUNCATED AT 250 WORDS)

Stable isotope labeling of lead compartments in rats with ultralow lead concentrations

The role of the mammalian skeleton as an endogenous lead source is unclear. This is due in part to difficulties in distinguishing mobilized skeletal lead from other endogenous and exogenous lead sources. Therefore, we have applied ultraclean stable lead isotope techniques to label skeletal and soft tissue lead compartments within the rat with distinguishable lead isotopic signatures. Female Wistar (defined flora) rats were fed 206Pb-enriched drinking water ([Pb] = 110 ng/ml) and sacrificed after durations of 2, 4, 7, and 14 days. Blood, kidney, vertebra, and tibia tissues were analyzed for lead concentrations and stable isotopic compositions. The resulting isotopic ratios in soft (blood and kidney) and skeletal (vertebrae and tibia) tissues differed by approximately 40% after 2 days exposure to the 206Pb tracer. More than 90% of the tracer isotopic signature was contained in the soft tissues after 10 days exposure, while skeletal tissues acquired only approximately 50% of the tracer by the end of the study. Because these animals were maintained under trace metal-clean conditions, they contained lead concentrations in whole blood (0.3-3 ng/g), kidney (11-27 ng/g dry wt), and bone (35-70 ng/g dry wt) tissues that are the lowest known reported for contemporary terrestrial mammals, and they (in bone) are comparable to levels in preindustrial mammals. The elevated concentrations of lead in kidney (fresh weight) relative to levels in blood are consistent with the presence of specific lead-binding sites in the kidney at very low levels of exposure.