A rationale for lowering the blood lead action level from 10 to 2μg/dL

Gilbert, Steven G.; Weiss, Bernard

doi:10.1016/j.neuro.2006.06.008

Cited by 310 publications

(206 citation statements)

References 43 publications

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“…The observed elevations in blood lead concentrations, while not considered overtly toxic, would nevertheless contribute to cumulative lead burdens, and would be additive with further meals of contaminated venison. Observed blood lead concentrations of up to 3.8 mg/dL, and daily means of 2.3 and 2.2 mg/dL in the experimental animals, do approach what is considered significant with respect to adverse effects in humans by contemporary assessments [35,36]. Whereas the CDC advisory level for intervention in individual children is 10 mg/dL in blood [37], studies now associate as little as 2 mg/dL with increased risk of cardiovascular mortality in adults [15] and impaired cognitive function in children [38].…”

Section: Discussionmentioning

confidence: 80%

Lead Bullet Fragments in Venison from Rifle-killed Deer: Potential for Human Dietary Exposure

Hunt¹

2009

Ingestion of Lead From Spent Ammunition: Implications for Wildlife and Humans

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Human consumers of wildlife killed with lead ammunition may be exposed to health risks associated with lead ingestion. This hypothesis is based on published studies showing elevated blood lead concentrations in subsistence hunter populations, retention of ammunition residues in the tissues of hunter-killed animals, and systemic, cognitive, and behavioral disorders associated with human lead body burdens once considered safe. Our objective was to determine the incidence and bioavailability of lead bullet fragments in hunter-killed venison, a widely-eaten food among hunters and their families. We radiographed 30 eviscerated carcasses of White-tailed Deer (Odocoileus virginianus) shot by hunters with standard lead-core, copper-jacketed bullets under normal hunting conditions. All carcasses showed metal fragments (geometric mean = 136 fragments, range = 15-409) and widespread fragment dispersion. We took each carcass to a separate meat processor and fluoroscopically scanned the resulting meat packages; fluoroscopy revealed metal fragments in the ground meat packages of 24 (80%) of the 30 deer; 32% of 234 ground meat packages contained at least one fragment. Fragments were identified as lead by ICP in 93% of 27 samples. Isotope ratios of lead in meat matched the ratios of bullets, and differed from background lead in bone. We fed fragment-containing venison to four pigs to test bioavailability; four controls received venison without fragments from the same deer. Mean blood lead concentrations in pigs peaked at 2.29 mg/dL (maximum 3.8 mg/dL) 2 days following ingestion of fragment-containing venison, significantly higher than the 0.63 mg/dL averaged by controls. We conclude that people risk exposure to bioavailable lead from bullet fragments when they eat venison from deer killed with standard lead-based rifle bullets and processed under normal procedures. At risk in the U.S. are some ten million hunters, their families, and low-income beneficiaries of venison donations.

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Section: Discussionmentioning

confidence: 80%

Lead Bullet Fragments in Venison from Rifle-killed Deer: Potential for Human Dietary Exposure

Hunt¹

2009

Ingestion of Lead From Spent Ammunition: Implications for Wildlife and Humans

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“…Currently, the choice of threshold is relatively arbitrary because blood lead level thresholds indicating neurotoxic risk during childhood have not yet been established. Thus far, findings have led investigators to suggest that blood lead levels as low as 2.0 μg/dL may indicate significant neurotoxic risk [2]; findings may suggest that increments of 0.5 μg/dL distinguish whether and how neurobehavioral function is altered [16][17][18][19]. Given the complexity of child brain development, it would not be surprising to find that different brain pathways, and thus different neurobehavioral functions, are associated with different (low) level thresholds.…”

Section: Discussionmentioning

confidence: 99%

“…The current blood lead threshold for toxicity is 10 μg/dL; however, increasing numbers of studies suggest that low-level environmental lead exposure yielding child blood lead levels consistently below 10 μg/dL are associated with neurocognitive and motor deficits [2]. Children living in lower socio-economic conditions are at exponentially higher risk of lead exposure [3] suggesting a major health disparity with life-long implications [4].…”

Section: Introductionmentioning

confidence: 99%

A Bland–Altman Comparison of the Lead Care® System and Inductively Coupled Plasma Mass Spectrometry for Detecting Low-Level Lead in Child Whole Blood Samples

et al. 2010

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Chronic childhood lead exposure, yielding blood lead levels consistently below 10 μg/dL, remains a major public health concern. Low neurotoxic effect thresholds have not yet been established. Progress requires accurate, efficient, and cost-effective methods for testing large numbers of children. The LeadCare® System (LCS) may provide one ready option. The comparability of this system to the "gold standard" method of inductively coupled plasma mass spectrometry (ICP-MS) for the purpose of detecting blood lead levels below 10 μg/dL has not yet been examined. Paired blood samples from 177 children ages 5.2-12.8 years were tested with LCS and ICP-MS. Triplicate repeat tests confirmed that LCS and ICP-MS had comparable repeatability. As compared with ICP-MS, LCS had a negative bias of 0.457 μg/dL with an average variability of 1.0 μg/dL. The reproducibility and precision of the LCS is appropriate for the evaluation and monitoring of blood lead levels of individual children in a clinical setting. Recent research however has suggested that increments as small as 0.5 μg/dL may distinguish those at risk of low-level lead-induced neurotoxicity. Thus, we also conclude that the LCS is not useful for research applications attempting to identify neurotoxic effect thresholds for chronic lowest level lead exposure in children. For these types of research applications, a convenient and low-cost device is needed for the precise detection of child blood lead levels below 10 μg/dL.

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“…We note in passing that the research is quite conclusive that very low blood lead concentrations in children -concentrations well below the current CDC level of concern -are associated with subtle deficits in neurobehavioral function that can have important effects on children's life paths (Canfield and Jusko, in press;Gilbert and Weiss, 2006), irrespective of the issue of nonlinearity; Bowers and Beck do not in any way address this. Simulated blood lead concentrations and IQ from Canfield et al (2003).…”

Section: Dear Dr Cranmermentioning

confidence: 93%

Response to: “What is the meaning of non-linear dose–response relationships between blood lead concentrations and IQ?”

et al. 2006

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KeywordsLead; IQ; Non-linear; Dose-dependent; Children Dear Dr. CranmerStudies of pediatric lead exposure and IQ suggest that the association between measured blood lead concentrations and IQ is nonlinear, with the decline in IQ greater at lower levels of exposure (Bellinger and Needleman, 2003;Canfield et al., 2003;Jusko et al., 2005;Lanphear et al., 2005). In their recent paper, Bowers and Beck (2006) claim to show that this nonlinearity is artificial because a nonlinear dose-response function is an inevitable result of any regression on data with the distributional characteristics common to these studies. To support this claim, the authors conduct a demonstration by matching the nth percentile of lognormally distributed lead with the (100 -n)th percentile of normally distributed IQ and show that the resultant regression line has a nonlinear slope similar in shape to those reported by Canfield et al. (2003) and Lanphear et al. (2005). From this result they conclude that "any environmental measure that is lognormally distributed and any cognitive score that is normally distributed will by necessity have a non-linear slope." This argument is fundamentally flawed owing to a misunderstanding of the meaning of a statistical regression model. Equally important is that, regardless of how one evaluates their claim about nonlinearity, the most important conclusions from studies of pediatric lead exposure are not fundamentally altered.

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A rationale for lowering the blood lead action level from 10 to 2μg/dL

Cited by 310 publications

References 43 publications

Lead Bullet Fragments in Venison from Rifle-killed Deer: Potential for Human Dietary Exposure

Lead Bullet Fragments in Venison from Rifle-killed Deer: Potential for Human Dietary Exposure

A Bland–Altman Comparison of the Lead Care® System and Inductively Coupled Plasma Mass Spectrometry for Detecting Low-Level Lead in Child Whole Blood Samples

Response to: “What is the meaning of non-linear dose–response relationships between blood lead concentrations and IQ?”

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