Blood Lead Levels in Andean Infants and Young Children in Ecuador: An International Comparison

Lead seasonality: Affect children's blood lead levels and implication for lead exposure prevention

Lead seasonality attributed to the patterns of Pb variation in the natural environment should be considered in the Pb risk analysis and related to the seasonality evident in humans. In this study, we integrate the Xi'an soil and dust lead seasonality data (554 surface soil samples and 554 road dust samples in three seasons) to evaluate the seasonal lead burden on children and propose the implications for children's lead exposure prevention strategies considering the lead seasonality and the influences from urban land use and children's living environment. The results showed that most seasonal variation patterns of soil and dust Pb are observed in winter (cold season), which coincided with the observation of higher children's blood lead levels in winter, although the strong correlation coefficients between children's blood lead levels (BLLs) and soil/dust Pb are observed in summer. The combinations of meteorological factors and anthropogenic pollutant emission strongly determine the metal seasonal variations. Those arrays of evidence suggest that lead seasonality is multifactorial within the environment and humans. Land uses and living environments such as old residential areas, heavy traffic, and fewer green parks, etc. have a significant impact on the increase of children's BLLs. Lead exposure prevention is proposed by BLLs warning and effective measure of reduction ≤ 50 μm soil/dust size fraction in winter.

Lead content in cinnamon and its health risk assessment for Ecuadorian consumers

Lead (Pb) is a poisonous metal that affects organs and the nervous system. Its presence in spices such as cinnamon has been identified as a potential human exposure pathway. In late October 2023, a safety alert was issued in the United States regarding four children with elevated Pb levels in their blood after consuming apple-cinnamon fruit puree manufactured and exported by an Ecuadorian company. Thus, this study aimed to determine the Pb content in 61 ground and stick cinnamon samples, from different commercial brands and lots sold in Ecuador. Results showed that ground cinnamon samples had almost twice the level of Pb (0.80 ± 0.75 mg/kg) than stick samples (0.36 ± 0.28 mg/kg). Three ground samples had Pb content above the maximum level established by Ecuadorian and European Union regulations (2.0 mg/kg). A Kruskal-Wallis test showed significant differences in Pb content between ground and stick cinnamon (p < 0.05). The HQ values showed negligible non-carcinogenic effects for children and adults, even at the highest Pb content. However, the carcinogenic risk of ground cinnamon at maximum and mean Pb concentrations was found for the population. Our study highlights the deficiencies in current surveillance systems and the lack of effective national regulations for exposure to foodborne metals.

Chemical characterization of baby food consumed in Italy

In this study, a total of 30 elements (essential and non-essential or toxic) were determined in 25 foods consumed in Italy by children aged 0-6 months and produced in Europe. Inductively Coupled Plasma-Atomic Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry were used as measurement techniques for the elements of interest. The estimated intakes for one-year-old infants were compared with risk estimators and nutritional requirements. Data indicate that commercially available baby food in Italy provides an excellent contribution for Mn, Cu, Fe, Zn, Ca, K, and P, covering up to approximately 70% of the adequate intake (AI) for an infant aged 6-12 months. The intake of detectable toxic elements was always below the safety limit: even the most concentrated toxic elements never exceeded about 86% of the Provisional Tolerable Weekly Intake (PTWI). This result indicates that the analyzed baby food is of good quality and does not pose risks to children's health.

Impact of lead exposure on the thyroid glands of individuals living in high- or low-lead exposure areas

Ecuador was an endemic area for iodine deficiency; however, due to the population consumption of iodized table salt, the country is nowadays considered iodine sufficient. Despite the population consumption of iodized salt for more than 50 years, the prevalence of hypothyroidism has increased in recent years. A similar increment has been reported for thyroid cancer (TC) becoming the second most common cancer in women and seventh most common cancer in men. High blood lead (BPb) level is a controversial causal factor for impaired thyroid function as well as a debated environmental cause for the increased incidence of TC. To study the association between BPb and thyroid function, anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies, and the presence of benign and malignant thyroid nodules in Ecuadorian individuals living in high lead exposure (HE) areas compared with those living in low lead exposure (LE) area. We evaluated 197 euthyroid individuals: 70 from Esmeraldas (close to a petrol refinery) and 27 from La Victoria de Pujilí (Pb-glazing ceramics), considered HE areas, and 100 from Quito, considered the LE area. In parallel, we evaluated 187 patients with hypothyroidism (60, 27, and 100 patients from Esmeraldas, Pujilí, and Quito, respectively). BPb was detected using atomic absorption spectroscopy, while thyroid-stimulating hormone (TSH), free-thyroxine (FT4), and autoantibodies were measured using chemiluminescence assays. Thyroid ultrasonography was performed in 300 individuals and fine-needle aspiration biopsy (FNA) was performed only when required based on the guidelines of the American Thyroid Association. The BPb levels (mean ± SD) in the HE areas were increased (8.5 ± 7.4) than those in the LE area (3.2 ± 2.4, P < .001). No significant associations were observed between BPb and TSH, FT4, or thyroid antibody levels. Enlarged thyroid glands and larger thyroid nodules were primarily observed in HE areas. Just 1 TC was observed. High BPb levels detected in HE areas were not associated with thyroid function or thyroid autoantibodies; however, increased thyroid size and numbers of thyroid nodules were observed, demanding further actions to control lead contamination in these Ecuadorian areas.

A review of studies on blood lead concentrations of traditional Mexican potters

BACKGROUND

Traditional Mexican potters and their families have been occupationally exposed to lead for centuries; however, studies on blood lead levels (BLL) and their adverse health impact on this population are scarce. There is no safe BLL, even at 1 μg/dL there are associated health effects.

OBJECTIVE

To systematize and characterize Mexican potters' historic lead exposure through their BLL and associated health outcomes.

METHODS

Using PRISMA guidelines, we conducted a systematic review through January 2021 of published studies on BLL and associated health outcomes in Mexican potters.

RESULTS

Fifteen studies containing data from 1980 to 2013 met the inclusion criteria and were published between 1980 and 2018. Study populations ranged from n = 5 to n = 457, and included adult potters (mean BLL 37.9 ± 16.2 μg/dL) and/or their children (mean BLL 22.5 ± 10.5 μg/dL). Studies reported on general lead poisoning symptoms, neurotoxic and nephrotoxic outcomes as well as correlated biomarkers.

CONCLUSIONS

Our results confirm high occupational and para-occupational lead exposure. Despite governmental and non-governmental initiatives to promote lead-free glazes, lead continues to be used by traditional potters and their families.

Childhood lead exposure of Amerindian communities in French Guiana: an isotopic approach to tracing sources

In French Guiana were detected high lead (Pb) levels in blood of Amerindian people. Lead exposure is a serious hazard that can affect the cognitive and behavior development. People can be exposed to Pb through occupational and environmental sources. Fingerprinting based on stable Pb isotopes in environmental media is often used to trace natural and anthropogenic sources but is rarely paired with blood data. The objective of this study was to determine the main factors associated with high Blood Lead Levels (BLL). Soil, manioc tubers, food bowls, beverages, wild games, lead pellets and children blood were sampled in small villages along the Oyapock River. children BLL ranged between 5.7 and 35 µg dL^-1, all exceeding 5 µg dL^-1, the reference value proposed in epidemiologic studies for lead poisoning. Among the different dietary sources, manioc tubers and large game contained elevated Pb concentrations while manioc-based dishes were diluted. The isotopes ratios (²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb) of children blood overlapped these of lead shots and meals. These first results confirm for the first time, the diary consumption of manioc-based food as the main contributor to Amerindian children's BLL in French Guiana, but don't exclude the occasional exposure to lead bullets by hunting activities. This is a specific health concern, since previous studies have shown that these same villagers present high levels of mercury (Hg). These communities are indeed subject to a double exposure to neurotoxic metals, Hg and Pb, both through their diet. The farming activity is based on manioc growing, and explaining that this ancestral practice can induce serious health risks for the child's development may seriously affect their food balance and cultural cohesion.

Cognitive Impairment Induced by Lead Exposure during Lifespan: Mechanisms of Lead Neurotoxicity

Lead (Pb) is considered a strong environmental toxin with human health repercussions. Due to its widespread use and the number of people potentially exposed to different sources of this heavy metal, Pb intoxication is recognized as a public health problem in many countries. Exposure to Pb can occur through ingestion, inhalation, dermal, and transplacental routes. The magnitude of its effects depends on several toxicity conditions: lead speciation, doses, time, and age of exposure, among others. It has been demonstrated that Pb exposure induces stronger effects during early life. The central nervous system is especially vulnerable to Pb toxicity; Pb exposure is linked to cognitive impairment, executive function alterations, abnormal social behavior, and fine motor control perturbations. This review aims to provide a general view of the cognitive consequences associated with Pb exposure during early life as well as during adulthood. Additionally, it describes the neurotoxic mechanisms associated with cognitive impairment induced by Pb, which include neurochemical, molecular, and morphological changes that jointly could have a synergic effect on the cognitive performance.

Chronic developmental lead exposure increases μ-opiate receptor levels in the adolescent rat brain

Childhood lead (Pb2+) intoxication is a global public health problem best known for producing deficits in learning and poor school performance. Human and preclinical studies have suggested an association between childhood Pb2+ intoxication and proclivity to substance abuse and delinquent behavior. While environmental factors have been implicated in opioid addiction, less is known about the role of exposure to environmental pollutants on the brain opioid system. Opioid receptors are involved in the biological effects of opioids and other drugs of abuse. In this study, we examine the effect of chronic developmental Pb2+ exposure (1500 ppm in the diet) on μ-opioid receptor (MOR) levels in the rat brain using [3H]-d-Ala2-MePhe4-Gly-ol5 enkephalin ([3H]-DAMGO) quantitative receptor autoradiography at different developmental stages (juvenile, early-adolescent, late adolescent and adult) in male and female rats. Our results indicate that chronic developmental Pb2+ exposure increases the levels of [3H]-DAMGO specific binding to MOR in juvenile and early adolescent Pb2+-exposed male and female rat brain with no changes in late-adolescent (PN50) and minor changes in Pb2+-exposed adult male rats (PN120). Specifically, at PN14, Pb2+-exposed males had an increase in MOR binding in the lateral posthalamic nuclei (LPTN), and Pb2+-exposed females had increased MOR binding in LPTN, medial thalamus, and hypothalamus. At PN28, Pb2+-exposed males had increased MOR levels in the striatum, stria medullaris of the thalamus, LPTN, medial thalamus, and basolateral amygdala, while Pb2+-exposed females showed an increase in nucleus accumbens core, LPTN, and medial thalamus. No changes were detected in any brain region of male and female rats at PN50, and at PN120 there was a decrease in MOR binding of Pb2+-exposed males in the medial thalamus. Our findings demonstrate age and gender specific effects of MOR levels in the rat brain as a result of chronic developmental Pb2+ exposure. These results indicate that the major changes in brain MOR levels were during pre-adolescence and early adolescence, a developmental period in which there is higher engagement in reward and drug-seeking behaviors in humans. In summary, we show that chronic exposure to Pb2+, an ubiquitous and well-known environmental contaminant and neurotoxicant, alters MOR levels in brain regions associated with addiction circuits in the adolescent period, these findings have important implications for opioid drug use and abuse.

Environmental injustice and childhood lead exposure in peri-urban (ger) areas of Darkhan and Erdenet, Mongolia

BACKGROUND

The ger ("tent city") areas in Mongolia are a product of rapid urbanization and transitional economic development combine with lack of institutional, administrative and financial capacity of governments to cope with the pace. These areas have become traps for inequities in social and environmental services and the associated effects on human health. Disparities in childhood lead exposure in such communities are largely unexplored.

METHODS

We measured the concentrations of lead in blood of children, aged 4-7 years, in Erdenet (Orkhon Province) and Darkhan (Darkhan-Uul Province), the second and third largest cities in Mongolia. A survey instrument was used to gather information on influencing factors on lead exposure and the Strengths and Difficulties Questionnaire (SDQ) was used to assess a spectrum of behavioral problems among the children.

RESULTS

The mean blood lead level (BLL) of children in the two cities was found to be 3.8 ± 2.6 μg/dL (range: < 1.5-17.2 μg/dL) and 27.8% of the children had BLLs ≥5 μg/dL. Average BLL of children in Erdenet (a mining center) was significantly higher than that for children in Darkhan, and there was statistically significant difference between average BLL of children who live in ger district (4.2 ± 2.8 μg/dL) compared to those of children in housing units within the city (3.2 ± 2.4 μg/dL). In spite of the low values, BLLs was significantly associated with a number of effects on the spectrum of behavioral disorders, specifically with the scores for hyperactivity, conduct disorder and pro-social behavior.

CONCLUSIONS

This study shows that childhood lead poisoning is common especially in ger communities of the urban areas of Mongolia. It contributes evidence showing that BLL low as 3.8 μg/dL can selectively activate some effects from a spectrum of likely behavioral disorders in children.

Low blood lead levels impair intellectual and hematological function in children from Cartagena, Caribbean coast of Colombia

Lead produces numerous biochemical and physiological changes in humans, including hematological disorders, toxic effects on the central nervous system and in the function of several organs. The aim of this study was to determine blood lead levels (BLL) in children from Cartagena, Colombia, associating those with hematological and liver damage markers, the intelligence quotient (IQ), as well as with gene expression of the aminolevulinate dehydratase (ALAD), superoxide dismutase 1 (SOD1), gamma interferon (INF-γ), tumor necrosis factor (TNF) and tumor protein (p53). To achieve this purpose, 118 blood samples were collected from children 5-16 years old, with their respective informed consent from their parents. BLL was measured by atomic absorption; hematological parameters were obtained with automated systems; plasma was utilized to analyze hepatic toxicity markers, alanine aminotransferase (ALT), gamma-glutamyltransferase (γ-GT) and alkaline phosphatase (ALP); the Kaufman Brief Intelligence Test (K-BIT) was administered to measure the IQ; and gene expression was quantified from blood RNA. The mean BLL was 1.7±0.3μg/dL. A low proportion of the children (3.4%) had BLL above the CDC recommended limit (5μg/dL). BLL were correlated weakly, but negatively with child age, weight, height, body mass index, platelets wide distribution, mean platelet volume, γ-GT and IQ. There were not significant changes in the expression of evaluated genes. These results support the hypothesis that BLL below 5μg/dL may still be a detrimental factor on children's cognitive abilities, development and hematology, in line with recent concerns that there is no safe level of pediatric lead exposure.

Blood lead levels in a group of children: the potential risk factors and health problems

OBJECTIVE

To investigate blood lead levels in schoolchildren in two areas of Egypt to understand the current lead pollution exposure and its risk factors, aiming to improve prevention politicies.

SUBJECTS AND METHOD

This was a cross-sectional study in children (n=400) aged 6-12 years recruited from two areas in Egypt (industrial and urban). Blood lead levels were measured using an atomic absorption method. Detailed questionnaires on sources of lead exposure and history of school performance and any behavioral changes were obtained.

RESULTS

The mean blood lead level in the urban area of Egypt (Dokki) was 5.45±3.90μg/dL, while that in the industrial area (Helwan) was 10.37±7.94μg/dL, with a statistically significant difference between both areas (p<0.05). In Dokki, 20% of the studied group had blood lead levels≥10μg/dL, versus 42% of those in Helwan. A significant association was found between children with abnormal behavior and those with pallor with blood lead level≥10μg/dL, when compared with those with blood lead level<10μg/dL (p<0.05). Those living in Helwan area, those with bad health habits, and those living in housing with increased exposure were at a statistically significantly higher risk of having blood lead level≥10μg/dL.

CONCLUSION

Lead remains a public health problem in Egypt. High blood lead levels were significantly associated with bad health habits and housing with increased exposure, as well as abnormal behavior and pallor.

Essential and toxic elements in meat of wild birds

Essential and toxic elements were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES), mass spectrometry (MS), and atomic absorption (AS) in meat of 14 migratory birds originating from central and northern Europe to provide baseline data regarding game meat consumed in central Italy. In all samples analyzed, cobalt (Co) and chromium (Cr) (total) levels were <0.326 mg/kg_ww. For nonessential or toxic elements, arsenic (As), barium (Ba), cadmium (Cd), stannous (Sn), thallium (Tl), tellurium (Te), titanium (Ti), cerium (Ce), lantanium (La), and uranium (U) concentrations were <0.326 mg/kg_ww, thorium (Th) <1.63 mg/kg_ww, and mercury (Hg) <0.0163 mg/kg_ww. When detectable, lead (Pb) concentrations always exceeded maximal admissible levels for metal (0.1 mg/kg _ww) established by the European Commission for meat. These findings indicate that elevated Pb concentrations in game ingested by humans may be a cause for concern.

Blood-borne biomarkers and bioindicators for linking exposure to health effects in environmental health science

Environmental health science aims to link environmental pollution sources to adverse health outcomes to develop effective exposure intervention strategies that reduce long-term disease risks. Over the past few decades, the public health community recognized that health risk is driven by interaction between the human genome and external environment. Now that the human genetic code has been sequenced, establishing this "G × E" (gene-environment) interaction requires a similar effort to decode the human exposome, which is the accumulation of an individual's environmental exposures and metabolic responses throughout the person's lifetime. The exposome is composed of endogenous and exogenous chemicals, many of which are measurable as biomarkers in blood, breath, and urine. Exposure to pollutants is assessed by analyzing biofluids for the pollutant itself or its metabolic products. New methods are being developed to use a subset of biomarkers, termed bioindicators, to demonstrate biological changes indicative of future adverse health effects. Typically, environmental biomarkers are assessed using noninvasive (excreted) media, such as breath and urine. Blood is often avoided for biomonitoring due to practical reasons such as medical personnel, infectious waste, or clinical setting, despite the fact that blood represents the central compartment that interacts with every living cell and is the most relevant biofluid for certain applications and analyses. The aims of this study were to (1) review the current use of blood samples in environmental health research, (2) briefly contrast blood with other biological media, and (3) propose additional applications for blood analysis in human exposure research.

Current sources of lead exposure and their relative contributions to the blood lead levels in the general adult population of Northern France: The IMEPOGE Study, 2008-2010

There is justification for limiting lead (Pb) exposure as much as possible, given its impact on health at low concentrations. Consequently, the aim of this study was to measure blood lead levels (BLL) and examine exposure factors related to BLL variations in the general adult population of northern France, a current and past industrial area. Two thousand inhabitants of northern France, aged between 20 and 59 years, were recruited using the quota method with caution. Blood lead levels were quantified by inductively coupled plasma-mass spectroscopy (ICP-MS), and variation factors were studied separately in men and women using multivariate stepwise linear and logistic regression models. The geometric mean of the BLL was 18.8 μg/L (95% confidence interval [CI]: 18.3-19.3). Occupational factors affected BLL only in men and represented 14% of total explained variance of BLL. External occupational factors significantly increasing mean levels of BLL were tobacco, consumption of some beverages (wine, coffee, tea, and/or tap water), raw vegetables, housing characteristics (built prior to 1948, Pb piping in the home) and do-it-yourself or leisure activities (paint stripping or rifle shooting). Consumption habits accounted together for 25% and 18% of the total explained variance, respectively, in men and women. Industrial environment did not significantly contribute to BLL variations. Blood lead levels observed in the general population of this industrial part of France did not appear to be excessively elevated compared to values found internationally. Nonetheless, these BLL remain a public health issue in regard to nonthreshold toxicity attributed to Pb.