Declining blood lead and zinc protoporphyrin levels in Ecuadorian Andean children

ObjectivesTo investigate current lead (Pb) exposure in children living in Andean Ecuadorian communities. Blood Pb (PbB) and zinc protoporphyrin (ZPP) levels were used respectively as biomarkers of acute and chronic Pb poisoning. The current PbB–ZPP levels were compared with previous pediatric PbB–ZPP levels recorded over years in the study area.Design and methodsSamples of whole blood were collected from 22 Andean children of Quechua and Mestizo backgrounds and measured for PbB concentrations by graphite furnace atomic absorption spectroscopy. ZPP/heme ratio and ZPP whole blood (ZPP WB) levels were measured with a hematofluorometer.ResultsThe mean PbB level for children in the current study group was 14.5 μg/dL, which was significantly lower than the mean PbB level of 41.1 μg/dL found in the same study area in the 1996–2000 test period, and lower than the 22.2 μg/dL mean level found in the 2003–2007 period. The current mean ZPP/heme ratio was 102.1 μmol/mol, and the mean ZPP WB level was 46.3 μg/dL, both lower than values previously found in children in the study area.ConclusionWhile the current pediatric PbB–ZPP levels in the study area remain elevated in some children, the overall levels indicate a decline relative to levels observed in the same Pb-contaminated area in the period between 1996 and 2007. The elevated ZPP levels suggest a history of chronic Pb exposure, and potential iron deficiency in some children. The overall reduction in PbB–ZPP levels suggests a positive outcome of a Pb-exposure education and prevention program, and the therapeutic intervention of succimer chelation therapy.     

Comparative analysis of zinc protoporphyrin and blood lead levels in lead-exposed Andean children

OBJECTIVES: The objective of this study was to investigate the zinc protoporphyrin/heme ratio (ZPP/heme) as a biomarker for chronic lead (Pb) poisoning in children with a history of high Pb exposure. DESIGN AND METHODS: ZPP/heme ratio was measured in blood samples from 78 children (44 females and 34 males) with persistent Pb exposure from Pb glazing of ceramics in a local cottage industry in the Andes Mountains of Ecuador. RESULTS: Mean blood lead (PbB) level was 26.4 microg/dL (SD: 23.2; range: 4.0-107.0), and the mean ZPP/heme ratio was 152.4 micromol/mol (SD: 190.6; range: 36.0-1064.0). A regression analysis of PbB level and ZPP/heme ratio revealed a significant association (r=0.761, p= <0.0001), with the logZPP showing a higher correlation with PbB (r=0.869, p= <0.0001). The ZZP/heme ratio decreased significantly with increasing age (ANOVA, p=0.030). The mean ZPP/heme ratios for females and males were 139.6 and 169.0 micromol/mol, respectively, and were not statistically different (t-test, p=0.504). CONCLUSION: The elevated ZPP/heme ratios, coupled with high PbB levels observed in this cohort of Andean children of Pb-glazing workers, suggest chronic Pb intoxication and probable iron deficiency.     

Observational study of erythrocyte protoporphyrin screening test for detecting low lead exposure in children: impact of lowering the blood lead action threshold

We examined a retrospective sample of 1800 children on whom both erythrocyte protoporphyrin (EP) and blood lead (BPb) measurements were taken. The primary objective was to ascertain whether EP is a cost-effective screening test for low but increased BPb concentrations and to establish the optimal thresholds. The data did not provide evidence of an EP threshold at low BPb concentrations; however, the data did show a significant age effect. A subset of 500 children for whom both EP and hematocrit data were available showed no correlation between those variables. Age-specific operating characteristic curves, total error, and cost analyses are presented. The latter sets bounds on the relative cost of EP testing, above which only BPb determination should be performed. The implications of these findings are discussed in light of impending changes in U.S. federal guidelines for preventing lead poisoning in young children.     

Zinc protoporphyrin level in blood determined by a portable hematofluorometer: a screening device for lead poisoning

An inexpensive portable fluorometer has been designed which can be used to determine the concentration of zinc protoporphyrin (ZPP) in a drop of unprocessed blood deposited on a disposable glass slide. No volume measurement of the blood sample need be made. The instrument displays the ZPP level in micrograms per deciliter of blood accurately and reproducibly, automatically calibrating each determination by comparing the blood fluorescence with that of a stable dye. The instrument, which we call a hematofluorometer, is ideally suited for use in primary screening for childhood and occupational lead intoxication. It can be used by public health personnel after a few minutes of instruction. Comparisons of ZPP levels obtained with the use of the hematofluorometer with erythrocyte protoporphyrin levels obtained using accepted extraction methods are presented.     

Inorganic lead exposure in the rat activates striatal cFOS expression at lower blood levels and inhibits amphetamine-induced cFOS expression at higher blood levels

The impact of inorganic lead exposure on dopamine (DA) neurotransmission in the basal ganglia was examined. Amphetamine (AMPH)-induced cFOS immunoreactivity (cFOS-IR) in the striatum was determined after a 3-week exposure to lead acetate (0, 50, or 250 ppm). On the 21st day of lead exposure, rats were challenged with AMPH (4 mg/kg i.p.) or saline vehicle (Veh) and were assayed for presence of cFOS-IR. In the untreated control (Con) group, AMPH challenge (Con/AMPH) increased cFOS-IR expression by approximately 35-fold over Veh challenge (Con/Veh) (P < 0.01). In the Pb50/Veh group, cFOS-IR expression was approximately 7-fold greater than in the Con/Veh group (P < 0.05). Given that there was negligible cFOS-IR expression in the Con/Veh group, this indicates that the Pb50 exposure induced cFOS expression. The increase in cFOS-IR in the Pb50/AMPH was also significant (P < 0.01), but it was not different from the Con/AMPH (P > 0.20). Neither the Pb250/Veh group nor the Pb250/AMPH group had a significant increase in cFOS-IR relative to Con/Veh (P > 0.20). These results indicate that chronic 50 ppm lead exposure induced a low but statistically significantly level of cFOS gene activation and that it did not affect the AMPH-induced cFOS activation. However, chronic 250 ppm lead exposure inhibited AMPH-induced activation of cFOS in the striatum by about 89%. Therefore, lead is capable of both activating cFOS expression at low levels of exposure (mean blood lead level 21.6 +/- 1.9 microg/dl) and inhibiting AMPH-induced cFOS expression at higher levels of exposure (mean blood lead level 47.4 +/- 2.6 microg/dl).     

新疆乌鲁木齐市儿童血铅水平及相关因素分析

目的调查乌鲁木齐市儿童血铅水平,分析儿童血铅含量及铅中毒的原因,寻找预防和降低铅中毒的方法和途径,为制定积极有效的干预措施提供科学依据。方法用原子吸收光谱分析仪检测儿童末梢血中铅的含量。结果 5 268例儿童中血铅浓度平均值为(40.55±22.23)μg/L,铅中毒儿童共133例,总检出率为2.52%;男童血铅水平明显高于女童(P<0.01);0～7岁儿童血铅浓度随年龄增长而增高,差异有统计学意义(P<0.01)。结论乌鲁木齐市儿童血铅水平低于中国其他城市,但高于西方发达国家。寻找污染来源,治理环境污染及注意家庭卫生,营养平衡,加大宣传力度,是减少儿童铅中毒最经济和最有效的方法。     

Allelic variation and environmental lead exposure in urban children

The advent of the Human Genome Project has allowed for increased understanding and sophistication in diagnosis, treatment methods, and overall care planning on the part of healthcare providers for children with genetic disorders. Genetics research dealing with polymorphic changes within a genome has opened the door to awareness of how dormant genetic alleles may become active when coupled with certain environmental insults. Such genetic aberrations may place a child at a higher risk for health disparities when exposed to environmental toxins. It has been posited that such exposure in children with an arylsulfatase-A (ASA) allelic variation is associated with increased risk for neurodevelopmental damage. This initial study contributes to this new field and supports development of finer-tuned methods to prevent ominous outcomes of lead exposure. The purpose of this study was to explore the incidence of children in a representative sample from a Midwest metropolitan city with positive test results for the ASA allelic variation who have been exposed to the environmental toxin lead. In this corollary study of 107 children, part of a parent study on the behavior of African American children prenatally exposed to cocaine, 45% were found to be heterozygous, 11% mutant homozygous, and 44% normal in terms of ASA allele or alleles. Further studies on neurodeficiencies, low-level exposure to environmental toxins, and allelic variations must be conducted before a relation between ASA allelic variance and environmental lead can be determined.     

Validity and interpretation of blood lead levels: a study of Danish school children

Blood lead concentrations were measured in a group of children from a group of 9- to 10-year-old school children in Aarhus, Denmark. The study group was selected as a high-level and a low-level lead group, as identified by the lead concentration in the circumpulpal dentine in deciduous teeth shed 2-3 years previously. The validity of the blood sampling technique was investigated in adult volunteers, and lead was determined by electrothermal atomic absorption. Capillary blood sampling by a finger-stick method was preferred, as the slight contamination caused by this technique was deemed acceptable. The children with the highest dentine lead levels (n = 70), had blood lead concentrations of 0.08-0.63 mumol/l and a geometric mean of 0.28 mumol/l. The children with lowest dentine levels (n = 76) had blood lead concentrations of 0.08-0.70 mumol/l and a geometric mean of 0.18 mumol/l. The blood lead concentrations were compared with interview data on behaviour, family habits, diet, parents' tobacco smoking and occupation, water lead measurements, and traffic counts. A total of 20% of the variation in blood lead was explained by parents' tobacco smoking, the child's number in the sibship, gender, and consumption of canned food at home.     

合肥市部分儿童外周血中铜、锌、钙、镁、铁和铅元素测定结果分析

目的 了解合肥市部分1～6岁儿童外周血中铜、锌、钙、镁、铁和铅元素水平,探讨铜、锌、钙、镁、铁和铅元素缺乏的综合防治措施,为儿童合理补充这些元素提供参考.方法 以在该院儿保门诊体检的4 507例1～6岁儿童为研究对象,采用原子吸收光谱仪,测定其外周血中铁、锌、钙、铜、镁和铅的含量.结果 结果表明,铜、锌、钙、镁、铁和铅元素的平均值均在正常值之内;通过进一步分析铜、锌、钙、镁和铁元素的缺乏率,得到锌元素的缺乏较为严重,从1周岁到6周岁的儿童,其锌元素的缺乏率分别为96.1%、83.2%、63.8%、49.8%、40.7%和38.6%.而其他铜、锌、钙、镁和铁元素的缺乏率较小.结论 儿童在1～6岁生长发育最快,容易导致缺乏锌元素和铁元素,且年龄越小越易缺乏.该结果为父母给儿童正确营养搭配,合理膳食提供了很好的参考.     

番禺区南村镇学龄前儿童锌、铁、钙、铅微量元素调查与分析

目的 探讨番禺区南村镇学龄前儿童血液中锌、铁、钙、铅的含量,以便健康地指导儿童膳食.方法 以2011年1 ~ 3月前来检查的1 400例0~6岁儿童为对象,利用北京普析通用TAS-990型原子吸收分光光度计进行血液中锌、铁、钙、铅4种微量元素测定,并对检测结果进行统计分析.结果 该镇儿童锌缺乏率为2%,铁缺乏率为0.79%,钙元素缺乏率0%,结果表明该镇儿童锌与铁元素缺乏率较低,钙元素并不缺乏;而铅中毒率高达26.79%,明显高于全国10.45%的水平;男女儿童性别之间差异无统计学意义(P>0.05).结论 该镇学龄前儿童锌、铁、钙元素含量处于较理想水平,而铅中毒率较高,应引起有关部门的高度重视.     

Increased blood lead levels in severe smoke inhalation

Lead-containing paint is common in structures built before 1977. Heated lead in burning paint can be aerosolized and absorbed directly into the bloodstream through the lungs. Acute lead intoxication has been reported in this setting. The objective of this study was to determine if victims of severe smoke inhalation secondary to closed-space fires have clinically important elevated blood lead levels. A case-control study, with a 2:1 ratio of cases to controls, was matched for age and sex. Cases were drawn from a prospective convenience sample of intubated victims of closed-space fires presenting to the ED of an urban tertiary burn center. Cases had blood lead levels obtained 24 hours postexposure. Matched control subjects had blood lead levels obtained during ED evaluation for a complaint unrelated to smoke inhalation. The difference between mean lead levels for cases and control subjects was expressed with a 95% confidence interval (CI). Among 22 cases, the mean lead level was 6.64 mug/dL (standard deviation [SD], 4.14 mug/dL). Among the 44 matched control subjects, mean lead level was 2.89 mug/dL (SD, 1.65 mug/dL). The mean difference between cases and control subjects was 3.75 mug/dL (95% confidence interval, 1.86-5.64). Although severe smoke inhalation is associated with a more than 2-fold statistically significant increase in blood lead levels, there is no evidence to suggest that these elevations are clinically important.     

3621例儿童血铅水平调查

目的调查2009年深圳市妇幼保健院门诊儿童血铅水平和铅中毒状况。方法采用钨舟原子吸收光谱法测定3621例0～12岁儿童血铅水平,对各年龄组儿童血铅值应用SPSS15.0软件进行分析。结果 3621例0～12岁儿童血铅水平为43.58μg/L,按年龄分为4组,组间差异有统计学意义,男、女童血铅水平分别为45.61、41.23μg/L,幼儿前期和小学阶段儿童血铅水平存在性别差异。血铅水平大于或等于100μg/L者130例,铅中毒率为3.59%,铅中毒率最低为婴儿组(2.76%),最高是小学阶段(7.05%);男童铅中毒51例,铅中毒率为4.16%,女童铅中毒49例,铅中毒为2.76%,中毒的比例在男女童间差异具有统计学意义(P0.05)。结论儿童血铅水平及中毒率随年龄增长而增加,男童血铅水平及中毒率均高于女童。