Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This original research article targeted the critical issue of lead (Pb) exposure in a vulnerable population. The study systematically measured lead intake and body burden among pregnant women, their newborns, and one- to three-year-old children living in Karachi, Pakistan, despite the ban on leaded petrol since 2001. Researchers employed a detailed cross-sectional design, assessing multiple potential exposure sources, food, water, house dust, respirable dust, soil, petrol, and surma (eye cosmetics) using advanced analytical methods, including inductively coupled plasma-mass spectrometry (ICP-MS) and lead isotope ratio (LIR) analysis. By collecting duplicate food samples, environmental samples (from dust, soil, water, and air), and blood from mothers, newborns, and children, the study not only quantified lead concentrations but also elucidated the relative contribution of each source to blood lead levels. The focus keyphrase “lead exposure assessment among pregnant women and children” underscores the study’s relevance for heavy metal certification initiatives seeking to identify and mitigate high-risk exposure routes.
Who was studied?
The population studied comprised 66 pregnant women attending a tertiary care hospital in Karachi, Pakistan, all of whom had resided in the city for at least four years and had at least one living child aged one to three years. Blood samples were collected from the pregnant women at delivery, from the umbilical cords of their newborns, and, in 52 cases, from their young children during a follow-up home visit. For a more granular analysis, eight families were selected from this cohort, representing high (~50 μg/dL), medium (~20 μg/dL), and low (~10 μg/dL) blood lead levels in the mothers. These families underwent comprehensive in-home environmental sampling over three days, allowing for detailed assessment of lead exposure pathways. The diverse sample captured a range of socioeconomic backgrounds and living environments within Karachi, a megacity with significant industrial activity and urban density, thereby ensuring that findings reflect varied real-world exposures relevant to both public health and regulatory frameworks.
Most important findings
| Key Finding | Detailed Description |
|---|---|
| Blood Lead Levels | Pregnant women had a mean blood lead level of 16.18 μg/dL, with 79% exceeding 10 μg/dL. Children showed even higher mean levels (21.87 μg/dL), and newborn cord blood closely mirrored maternal levels. Strong correlations existed between maternal, cord, and child blood lead (Spearman’s ρ up to 0.88, p <0.001). |
| Main Exposure Sources | For pregnant women, food was the primary exposure source (mean 62.37% bioaccessible lead), followed by respirable dust (mean 27.12%) and house dust. For young children, food and house dust contributed nearly equally (mean 39.75% and 38.12%, respectively), with children experiencing approximately threefold higher lead intake per body weight than mothers. Water and surma contributed negligibly. |
| Isotopic Analysis | Lead isotope ratios in maternal and cord blood were nearly identical, indicating direct maternal-fetal transfer. Children’s blood LIR was more closely aligned with contemporary environmental sources (food, dust, soil). Petrol and surma LIR profiles did not match blood LIR, confirming minimal current contribution. |
| Bioaccessibility and Cooking | Approximately 60% of lead in food and house dust was bioaccessible, but little lead was introduced during cooking, regardless of utensil type. Petrol and lubricant samples from local stations were well below regulatory thresholds (<0.083 mg/L). |
| Intervention Potential | The study identified that household wet-mopping could substantially reduce dust-borne lead exposure. Systematic surveillance and interventions targeting food and dust contamination are urgently needed. |
Key implications
The findings of this lead exposure assessment among pregnant women and children highlight that, in Karachi, the principal sources of lead are food and household dust, not water, petrol, or surma. For heavy metal certification programs, this underscores the necessity of rigorous testing and regulation of food and indoor dust, as well as the implementation of behavioral interventions like wet-mopping to reduce lead exposure in high-risk populations.
Citation
Fatmi Z, Sahito A, Ikegami A, Mizuno A, Cui X, Mise N, Takagi M, Kobayashi Y, Kayama F. Lead Exposure Assessment among Pregnant Women, Newborns, and Children: Case Study from Karachi, Pakistan. Int J Environ Res Public Health. 2017;14(4):413. doi:10.3390/ijerph14040413
Lead is a neurotoxic heavy metal with no safe exposure level. It contaminates food, consumer goods and drinking water, causing cognitive deficits, birth defects and cardiovascular disease. HMTC’s rigorous lead testing applies ALARA principles to protect infants and consumers and to prepare brands for tightening regulations.
