Elevated Blood Lead Levels In Children Research Articles

Traditional Eye Cosmetics and Cultural Powders as a Source of Lead Exposure.

We aimed to describe the characteristics of traditional eye cosmetics and cultural powders, including the types, lead concentrations, origin, and regional variation in product names, and assess the differences in blood lead levels (BLLs) between product users and non-users. We analyzed 220 samples of traditional eye cosmetics and cultural powders collected in New York City between 2013 and 2022 during lead poisoning investigations and store surveys. We compared the BLLs of children who used these products with those of non-users. Lead levels in traditional eye cosmetics surma and kohl were much higher than levels in kajal and other cultural powders. Although the terminologies surma, kohl, and kajal are often used interchangeably, findings suggest regional variations in the product names. The majority of the surma in this study were from Pakistan, kohl was from Morocco, and kajal was from India. The results also show that these products can contribute to elevated BLLs in children. Our study reveals that traditional eye cosmetics and cultural powders are used among children as young as newborns, and exposure to these products can significantly add to their lead body burden. The study findings also reveal that lead concentrations in these products can vary by product type and product names can vary by region. Public health officials must be cognizant of these unique variations and use culturally appropriate terminologies for these types of products because such distinctions can be critical when conducting risk assessments, risk communication, and risk reduction activities.

Prevalence of elevated blood lead level in children with global developmental delay and its relation with parental and child attributes

Background: Lead, a potential neurotoxin, is found in soil, water and air as a result of its non-biodegradable nature. Common sources of lead toxicity in children are household paints, leaded pipes for water supply, canned food, coloured toys, herbal/folk remedies and electronic wastes. Along with this, other child and parental attributes have been found to contribute to elevated blood lead level (EBLL). Objectives were to estimate the prevalence and risk factors of EBLL in children with global developmental delay (GDD). Methods: This hospital based cross sectional study was conducted between October 2019 and October 2021 at department of paediatrics of JNMCH, AMU, Aligarh. Data regarding clinical and sociodemographic characteristics as well as parental attributes was collected and entered on pre-designed proforma. Results: Among 94 children with GDD mean BLL was found to be 6.72±6.46 mcg/dl and in their mothers it was 6.74±6.46 mcg/dl (p=0.984). A high prevalence of EBLL (>5 mcg/dl) in children with GDD (53.20%) and their mothers (49.3%) was noted. Various child and parental attributes were identified as potential sources of exposure to lead. Conclusions: A high prevalence of EBLL in children with GDD in our study area might also suggest higher exposure from environmental sources such as soil, water, electronic waste, lead acid batteries, etc. For countries like ours which is rapidly undergoing industrialisation, these potential sources need to be identified promptly and swift action in this regard is needed in addition to preventive measures at personal and family levels.

Estimating the Effects of Soil Remediation on Children's Blood Lead near a Former Lead Smelter in Omaha, Nebraska, USA.

Background:Lead exposures from legacy sources threaten children’s health. Soil in Omaha, Nebraska, was contaminated by emissions from a lead smelter and refinery. The U.S. Environmental Protection Agency excavated and replaced contaminated soil at the Omaha Lead Superfund Site between 1999 and 2016.Objectives:The goal of this study was to assess the association of soil lead level (SLL) and soil remediation status with blood lead levels (BLLs) in children living near or on the site.Methods:We linked information on SLL at residential properties with children’s BLLs and assigned remediation status to children’s BLL measurements based on whether their measurements occurred during residence at remediated or unremediated properties. We examined the association of SLL and remediation status with elevated BLL (EBLL). We distinguished the roles of temporal trend and the intervention with time-by-intervention-status interaction contrasts. All analyses estimated odds ratios (ORs) with a generalized estimating equations approach to ensure robustness under the complex correlations among BLL measurements. All analyses controlled for relevant covariates including children’s characteristics.Results:EBLL () was associated with both residential SLL [e.g., ; 95% confidence interval (CI): 1.83, 2.19; vs. ] and neighborhood SLL [e.g., (95% CI: 1.62, 2.11; vs. )] before remediation but only with neighborhood SLL after remediation. The odds of EBLL were higher before remediation [OR 1.52 (95% CI: 1.34, 1.72)]. Similarly, EBLL was positively associated with preremediation status in our interaction analysis [interaction (95%CI: 1.02, 1.37)].Discussion:Residential and neighborhood SLLs were important predictors of EBLLs in children residing near or on this Superfund site. Neighborhood SLL remained a strong predictor following remediation. Our data analyses showed the benefit of soil remediation. Results from the interaction analyses should be interpreted cautiously due to imperfect correspondence of remediation times between remediation and comparison groups. https://doi.org/10.1289/EHP8657

The impact of elevated blood lead levels in children on maternal health-related quality of life

Kabwe is a mining town in Zambia that has been ranked among “the ten most polluted places in the world” with previous findings of serious lead (Pb) pollution. In this study, we aim to examine the impact of childhood Pb poisoning on the health-related quality of life (HRQoL) of mothers in Kabwe. The HRQoL was assessed using the Short-Form 36 survey for 404 mothers coming from residences in 40 randomly selected standard enumeration areas (SEAs). Blood lead levels (BLLs) of the household members including the mothers themselves were measured. We found a significant positive correlation between the BLLs of the mothers and their children (R = 0.6385, p < 0.0001), while the BLLs of preschool-aged and school-aged children were significantly higher than those of their mothers and fathers. Using the data sets containing the BLLs of the household members, the age of the mothers, the household income, and the household SEA, we performed stepwise multiple linear regression analyses. The results showed significant negative associations between the representative BLL of household children and the BLL of preschool-aged children with the vitality and mental health scores of their mothers. Additionally, the BLL of school-aged children was only significantly associated with the mental health score of their mothers. By contrast, there was a significant negative association between the BLLs of the mothers with the social role functioning score. This suggests that elevated BLLs in children have a negative impact on the mental health conditions of their mothers regardless of the mothers’ BLL.

Follow-Up of Elevated Blood Lead Levels and Sources in a Cohort of Children in Benin.

Lead exposure is associated with poor cognitive development in children. Very few studies in sub-Saharan Africa (SSA) have studied blood lead levels (BLLs) and non-gasoline sources of exposure in children. Data from a birth cohort in Benin (2011–2013) suggested that 58% of 1-year-old children had BLLs > 50 ug/L. We aimed to investigate the prevalence of elevated BLLs (>50 µg/L and >100 µg /L) among 425 of these children at 6 years of age in 2016–2018 and to compare BLLs between age 1 and 6 years, and study sources of lead at age 6 years. BLLs were analysed by inductively coupled plasma mass spectrometry. Multiple linear regression and quantile regressions were used to study potential sources of lead. The prevalence of BLLs > 50 µg/L in children was 59.5% (Geometric Mean (GM) 56.4 µg/L, 95% CI: 54.1–58.7) at 6 years of age compared to 54.8% (GM 56.5 µg/L, 95% CI: 53.4–59.6) at 1 year of age. The prevalence of children with BLLs > 100 µg/L decreased from 14.4% at 1 year of age to 8.2% at 6 years of age. After adjustment for all other covariates, consumption of peanuts more than once per month was significantly associated with a 22.0% (95% CI: 4.6, 42.5) increment in BLLs at age 6 years compared with no consumption. Consumption of bushmeat killed by lead bullets at age 6 years was associated with an increase in the higher percentiles of BLLs (P75) compared with the absence of this source. Other potential sources of lead associated with BLLs with marginal significance were consumption of rice, paternal occupational exposure, and the presence of activity with the potential use of lead. This prospective cohort confirms the persistently high prevalence of elevated BLLs in children residing in a rural region in the south of Benin, as well as the presence of multiple and continuous sources of lead. These results highlight the need for prevention programs to reduce and eliminate lead exposure in children.

Blood Lead Levels of Children Using Traditional Indian Medicine and Cosmetics: A Feasibility Study.

BackgroundTraditional Indian cosmetics and Ayurvedic medicines may contain lead. Previous studies have shown a relationship between eye cosmetic use (kohl) in children and elevated blood lead levels (BLLs) > 10 µg/dL. However, an association between Ayurvedic use and elevated BLLs in children is unknown and understudied.MethodsWe assessed the feasibility of collecting BLLs in children attending Ayurvedic outpatient settings in India. Our pilot study took place over 3 days in the summer of 2010 at a large public Ayurveda hospital and a small pediatric clinic in southern India. Using a trained interpreter, we administered a standardized questionnaire in Malayalam, assessing sociodemographics, Ayurvedic medicine use, kohl use, and other potential risk factors for lead exposure, to parents of pediatric outpatients. We also analyzed BLLs using a portable lead analyzer.ResultsThe study enrolled 29 children (mean age, 3.8 years). The mean BLL was 6.7 µg/dL (SD = 3.5; range, 3.5–20.2). Seventy-two percent of the children used Ayurvedic medicine in the past 2 years and 55% reported kohl use. Mean BLL of Ayurvedic users and nonusers was 6.2 µg/dL and 8.5 µg/dL, respectively (P = .08). Kohl users had a statistically significant higher BLL than nonusers (8.0 µg/dL vs 5.3 µg/dL, P = .03).ConclusionsIt is feasible to collect BLLs in pediatric Ayurvedic outpatient clinics in southern India. Collaborative relationships with community members and hospital staff were essential. Further research is needed to investigate Ayurveda and kohl use as risk factors for elevated lead burden among Indian children.

Lead Testing in a Pediatric Population

Underscreening and problematic repeat lead testing in children. Identify proportion of underscreening for elevated blood-lead levels in children. For children who receive a lead test, measure the level of problematic repeat lead tests, defined as those with a high probability of not meeting recommended guidelines for lead testing in children measured using a combination of patients' age, test type and sequencing, days between tests, and encounter diagnosis coding. A population-based retrospective cross-sectional design. All health care services organizations in the state of Minnesota that delivered health services to the defined study population. The study population was a Medicaid cohort of 12 436 children aged 0 to 18 years observed over a 1-year period. Proportion of eligible children not receiving at least 1 lead test; proportion of problematic repeat lead tests. Thirty-five percent of children who should have received at least 1 lead test (n = 1714) during the study period did not. A total of 1856 children had at least 1 lead test and 190 had 2 or more. Fifty percent (50%) of the repeat tests were identified as problematic, representing 5.1% of the lead tests performed. Repeat tests performed in different health systems than the systems where the initial tests were performed had 5.3 times greater odds (adjusted odds ratio: 5.3 [95% confidence interval, 2.8-9.9]) of being problematic. The current approach to delivering mandatory lead testing across the state Medicaid population does not ensure that children are appropriately tested and has potential inefficiencies in that testing when it does take place. Use of multiple health care systems is associated with increased potential inefficiencies. Future Medicaid accountable care agreements between the state Medicaid program and participating health systems should emphasize clear population accountability for test screenings to improve patients' safety. A central queryable health resource or health information exchange may enable this.

Take-Home Lead Exposure Among Children With Relatives Employed at a Battery Recycling Facility—Puerto Rico, 2011

The recycling of lead has increased during the past 20 years, with more workers and their families potentially being exposed to lead from recycling facilities, including facilities that recycle lead-acid batteries. During November 2010-May 2011, four voluntary blood lead screening clinics for children of employees of a battery recycling facility in Puerto Rico were conducted. A total of 227 persons from 78 families had blood lead tests. Among 68 children aged <6 years, 11 (16%) had confirmed blood lead levels (BLLs) ≥10 µg/dL, the BLL at which CDC recommended individual intervention to reduce BLLs in 2010, and 39 (57%) children aged <6 years had venous or capillary BLLs ≥5 µg/dL, the reference value for elevated BLLs in children established by CDC in 2012. To determine whether take-home lead exposure contributed to the children's BLLs of ≥10 µg/dL, vehicle and household environmental samples were collected and analyzed. Eighty-five percent of vehicle dust samples and 49% of home dust samples exceeded the U.S. Environmental Protection Agency (EPA) level of concern of ≥40 µg/ft² (430.6 µg/m²) [corrected]. EPA began clean-up of employee homes and vehicles, focusing first on homes with children with BLLs ≥10 µg/dL. EPA also required that the company set up shower facilities, shoe washes, and clean changing areas at the battery recycling facility. Lastly, CDC assigned a case manager to provide education, environmental follow-up, and case management of all children with BLLs ≥5 µg/dL. On average, children's BLLs have decreased 9.9 µg/dL since being enrolled in case management.

Elevated blood lead levels and sources of exposure in the population of Kinshasa, the capital of the Democratic Republic of Congo

The objective of this study was to determine blood lead levels (BLLs) and the possible sources of exposure in the population of Kinshasa, the capital of the Democratic Republic of Congo. A cross-sectional survey was carried out from January to May 2008 in a representative sample of the Kinshasan population. BLL was measured in 275 individuals (53.4% women) aged 1-70 years in the urban area of Kinshasa and from 60 additional subjects in the rural area. Pb was also determined in environmental specimens (air and soil, indoor and outdoor). BLL in the study population ranged from 2.9 to 49.3 μg/dl (median, 9.9 μg/dl). The median BLL among children aged <6 years was 11.5 μg/dl (range: 3.0-37.8 μg/dl). Of these children, 71% had elevated BLL (≥10 μg/dl) and 22% had BLL ≥20 μg/dl. The proportion of elevated BLL (≥10 μg/dl) was higher for children aged <3 years than for children aged 3 to 5 years (97% vs 56%). A higher prevalence of elevated BLL was observed in urban compared with rural children (71% vs 20%). Significantly higher BLLs were also found in children whose mother consumed fired clay during pregnancy. Residential informal activities in the recycling of car batteries also contributed to elevated BLL in children. The elevated background of Pb exposure in the Kinshasan population indicates a public health issue that requires corrective actions. Pb-contaminated dust and air in children's home is an issue of public health concern. The use of leaded gasoline and the activities of car battery recycling in certain residences appear to constitute the main sources of exposure in the city of Kinshasa. The traditional use of fired clay for the treatment of gastritis by pregnant women is another significant contributor for elevated BLL in children.

Are Lead Risk Questionnaires Adequate Predictors of Blood Lead Levels in Children?

To evaluate the accuracy of the verbal lead risk assessment tool in identifying the presence of measurable blood lead levels (BLL) in children. A retrospective analysis comparing results of a verbal lead risk assessment tool intended to identify elevated BLL in children with actual capillary fingerstick lead screening laboratory data. Three hundred and forty-nine children aged 5 years and younger enrolled in Head Start during the 2008-2009 school year were evaluated. Sixty-nine children had complete data and were included for final analysis. Results of the verbal lead risk assessment and laboratory capillary fingerstick BLL. All 69 children had measurable BLL. The Pass group, 84.3% of the sample, had BLL scores of 2.2±1.5 μg/dl, while the Fail group, 15.7% of the sample, had BLL scores of 1.5±0.65 μg/dl. There was no significant difference in BLL between children that passed the verbal risk assessment and those that failed ( p>.05). The verbal lead risk assessment did not accurately predict measurable BLL in children. Universal BLL screening for children is necessary to identify low levels of lead so that parents and caretakers of children can be notified and assisted in identifying and eliminating sources of lead exposure.

Reduction of elevated blood lead levels in children in North Carolina and Vermont, 1996-1999.

BackgroundFew studies have examined factors related to the time required for children’s blood lead levels (BLLs) ≥ 10 μg/dL to decline to < 10 μg/dL.ObjectivesWe used routinely collected surveillance data to determine the length of time and risk factors associated with reducing elevated BLLs in children below the level of concern of 10 μg/dL.MethodsFrom the North Carolina and Vermont state surveillance databases, we identified a retrospective cohort of 996 children < 6 years of age whose first two blood lead tests produced levels ≥ 10 μg/dL during 1996–1999. Data were stratified into five categories of qualifying BLLs and analyzed using Cox regression. Survival curves were used to describe the time until BLLs declined below the level of concern. We compared three different analytic methods to account for children lost to follow-up.ResultsOn average, it required slightly more than 1 year (382 days) for a child’s BLL to decline to < 10 μg/dL, with the highest BLLs taking even longer. The BLLs of black children [hazard ratio (HR) = 0.84; 95% confidence interval (CI), 0.71–0.99], males (HRmale = 0.83; 95% CI, 0.71–0.98), and children from rural areas (HRrural = 0.83; 95% CI, 0.70–0.97) took longer to fall below 10 μg/dL than those of other children, after controlling for qualifying BLL and other covariates. Sensitivity analysis demonstrated that including censored children estimated a longer time for BLL reduction than when using linear interpolation or when excluding censored children.ConclusionChildren with high confirmatory BLLs, black children, males, and children from rural areas may need additional attention during case management to expedite their BLL reduction time to < 10 μg/dL. Analytic methods that do not account for loss to follow-up may underestimate the time it takes for BLLs to fall below the recommended target level.

Elevated Blood Lead Levels of Children in Guiyu, an Electronic Waste Recycling Town in China

BackgroundElectronic waste (e-waste) recycling has remained primitive in Guiyu, China, and thus may contribute to the elevation of blood lead levels (BLLs) in children living in the local environment.ObjectivesWe compared the BLLs in children living in the e-waste recycling town of Guiyu with those living in the neighboring town of Chendian.MethodsWe observed the processing of e-waste recycling in Guiyu and studied BLLs in a cluster sample of 226 children < 6 years of age who lived in Guiyu and Chendian. BLLs were determined with atomic absorption spectrophotometry. Hemoglobin (Hgb) and physical indexes (height and weight, head and chest circumferences) were also measured.ResultsBLLs in 165 children of Guiyu ranged from 4.40 to 32.67 μg/dL with a mean of 15.3 μg/dL, whereas BLLs in 61 children of Chendian were from 4.09 to 23.10 μg/dL with a mean of 9.94 μg/dL. Statistical analyses showed that children living in Guiyu had significantly higher BLLs compared with those living in Chendian (p < 0.01). Of children in Guiyu, 81.8% (135 of 165) had BLLs > 10 μg/dL, compared with 37.7% of children (23 of 61) in Chendian (p < 0.01). In addition, we observed a significant increasing trend in BLLs with increasing age in Guiyu (p < 0.01). It appeared that there was correlation between the BLLs in children and numbers of e-waste workshops. However, no significant difference in Hgb level or physical indexes was found between the two towns.ConclusionsThe primitive e-waste recycling activities may contribute to the elevated BLLs in children living in Guiyu.

Childhood Correlates of Blood Lead Levels in India

P-684 Introduction: Lead exposure has previously been associated with intellectual impairment in children in a number of international studies. In India, it has been reported that nearly half of the children have elevated blood lead levels (BLLs). However, little is known about risk factors for these elevated BLLs. Methods: We conducted a retrospective cross-sectional analysis of data from the Indian National Family Health Survey, a population-based study conducted in 1998–99. We assessed potential correlates of BLLs in 1,081 children who were <3 years of age and living in Mumbai or Delhi. We examined factors such as age, sex, religion, caste, mother's education, standard of living, breast feeding, and weight/height percentile. Results: Most children (76%) had BLLs between 5 and 20 μg/dL. Age, standard of living, weight/height percentile and total number of children ever born to mother were significantly associated with BLLs (log transformed) in multivariate regression models. As compared with children ≤3 months of age, 4–11 and 12–23 month olds had 84% and 146% higher BLLs, respectively (p<0.001). A low standard of living correlated with a 32.3% increase in BLLs (p=0.02). Children >95 percentile for their weight/height had 31% (p=0.03) higher BLLs as compared with those who were <5 percentile for their weight/height. Children from the same immediate family had highly correlated BLLs (correlation coefficient=0.48). Discussion and Conclusions: Our study found that increasing age, a lower standard of living index, >95 weight/height percentile, and higher total number of children ever born to mother were correlated with elevated BLLs in children <3 years of age in Mumbai and Delhi. The correlation between >95 percentile weight/height and higher BLL may reflect an impact of lead exposure on body habitus. Since, lead pollution is a public health issue of concern, the demonstration of factors correlated with BLLs in Indian children may aid in prioritization of children for lead screening and also in studying correctable factors. Although, progress has recently been made by phasing out leaded gasoline in India, exposure from many other sources (including the entrainment of lead oxide from combusted leaded gasoline into dust, water, and the food system) is likely to continue for many years to come. Further efforts to control lead pollution, especially in populations at high risk, should be considered.

Use of a geographic information system to track smelter-related lead exposures in children: North Lake Macquarie, Australia, 1991–2002

BackgroundTo determine patterns of childhood lead exposure in a community living near a lead and zinc smelter in North Lake Macquarie, Australia between 1991 and 2002.MethodsAn analysis of serial blood lead levels (BLL) of children less than 13 years of age in North Lake Macquarie participating in voluntary blood lead screening. Distance to the smelter and soil lead concentration of the child's place of residence was calculated. Categorical analysis of BLL by residential distance from smelter, residential soil lead concentration, age and year of sample was calculated. Linear regression models were fit for blood lead levels against residential distance from smelter, the log of residential soil lead concentration, age and year of BLL sample.ResultsGeometric mean BLLs were statistically significantly higher for distances less than 1.5 kilometres from the smelter and for residential soil lead concentrations greater than 300 ppm. Yearly BLLs since 1995 were statistically significantly lower than for preceding years, with an average decrease of 0.575 μg/dL per year since 1991. BLLs are statistically significantly higher for children whose age is 1 to 3 years old. Linear regression modelling of BLL predicted a statistically significant decrease in BLL of 3.0831 μg/dL per kilometre from the smelter and a statistically significant increase in BLL of 0.25 μg/dL per log of lead in residential soil. The model explained 28.2% of the variation in BLL.ConclusionResidential distance to the smelter, log of residential soil lead concentration, child's age and year of BLL sample are statistically significant factors for predicting elevated BLLs in children living near a North Lake Macquarie lead smelter.

Childhood Correlates of Blood Lead Levels in Mumbai and Delhi

BackgroundLead exposure has previously been associated with intellectual impairment in children in a number of international studies. In India, it has been reported that nearly half of the children have elevated blood lead levels (BLLs). However, little is known about risk factors for these elevated BLLs.MethodsWe conducted a retrospective cross-sectional analysis of data from the Indian National Family Health Survey, a population-based study conducted in 1998–1999. We assessed potential correlates of BLLs in 1,081 children who were < 3 years of age and living in Mumbai or Delhi, India. We examined factors such as age, sex, religion, caste, mother’s education, standard of living, breast-feeding, and weight/height percentile.ResultsMost children (76%) had BLLs between 5 and 20 μg/dL. Age, standard of living, weight/height percentile, and total number of children ever born to the mother were significantly associated with BLLs (log transformed) in multivariate regression models. Compared with children ≤3 months of age, children 4–11 and 12–23 month of age had 84 and 146% higher BLLs, respectively (p < 0.001). A low standard of living correlated with a 32.3% increase in BLLs (p = 0.02). Children greater than the 95th percentile for their weight/height had 31% (p = 0.03) higher BLLs compared with those who were below the 5th percentile for their weight/height.ConclusionsOur study found various factors correlated with elevated BLLs in children. The correlation between greater than the 95th percentile weight/height and higher BLL may reflect an impact of lead exposure on body habitus. Our study may help in targeting susceptible populations and identifying correctable factors for elevated BLLs in Mumbai and Delhi.

Blood lead levels and risk factors for lead poisoning in children and caregivers in Chuuk State, Micronesia

Lead poisoning is a preventable environmental disease. Children and developing fetuses are especially vulnerable; even low blood lead levels (BLLs) are linked with learning and behavioral problems. We assessed children's and their caregivers’ BLLs and risk factors for lead exposure in Chuuk State, Federated States of Micronesia. Children aged 2–6 years were randomly selected within 20 randomly selected villages. Children and caregivers provided venous blood, and caregivers offered information about possible risk factors for lead exposure. Mean BLLs were 39 μg/l for children and 16 μg/l for caregivers. Children with BLLs of ⩾100 μg/l (elevated) were 22.9 (95% CI: 4.5–116.0) times more likely to have a caregiver with an elevated BLL, 6.2 (95% CI: 1.4–27.3) times more likely to live on an outer island, and 3.4 (95% CI: 1.7–6.9) times more likely to have a family member who made lead fishing weights than did other children even after controlling for age and sex. For children, 61% of elevated BLLs could be attributed to making fishing weights. Caregivers with elevated BLLs were 5.9 (95% CI: 1.5–23.7) times more likely to live in a household that melted batteries than other caregivers even after controlling for age and education. For caregivers, 37% of the elevated BLLs could be attributed to melting batteries. The association of elevated BLLs in children and their caregiver suggests a common environmental exposure. Melting batteries to make fishing sinkers is a preventable source of lead exposure for children and their caregivers in Chuuk.

Lead sulphide and traditional preparations: routes for ingestion, and solubility and reactions in gastric fluid.

Lead sulphide frequently occurs as a fallacious materia medica in traditional preparations used throughout the Moslem world. Although one of the least soluble lead compounds, use of this material as an eye powder has been directly associated with elevated blood-lead levels in children. Data are presented from animal studies which show the primary route for ingestion of the eye cosmetic is not transcorneal transport. Conversion of the sulphide to the more soluble (and hence more readily absorbed) chloride form is shown to occur in gastric fluid and, significantly, a marked dependence of the rate of dissolution on particle size is found. This may explain the disparity in previous reported values for the extent of absorption of ingested lead sulphide.

LEAD AND δ-AMINOLÆVULINIC ACID DEHYDRATASE LEVELS IN MENTALLY RETARDED CHILDREN AND IN LEAD-POISONED SUCKLING RATS

There has been controversy over an association between elevated blood-lead levels in children and mental deficiency. This study has revealed a negative correlation (r=—0·81) between blood-lead levels and δ-aminolævulinic acid dehydratase (A.L.A.-dehydratase) activity in children. Significant decreases in enzyme activity occurred at lead levels considered to be in the upper range of normal (20-40 μg. per 100 ml.). When lead was fed to lactating rats there was a significant and commensurate reduction in both blood and brain A.L.A.-dehydratase activity in the suckling rat. These results suggest that even modest elevations of blood-lead may be associated with biochemical abnormalities in the child brain.