Prenatal exposure to toxic and essential trace elements in Syrian newborns: a meconium biomonitoring study

Prenatal exposure to toxic and essential trace elements represents an important public health concern because of its potential impact on fetal growth and neonatal health. Meconium has emerged as a valuable biomonitoring matrix that reflects cumulative fetal exposure during late pregnancy. However, biomonitoring data from low- and middle-income countries, including Syria, remain extremely limited. A cross-sectional biomonitoring study was conducted among 123 full-term newborns from Damascus and Latakia, Syria, between August and September 2025. Meconium samples were collected within the first hours after birth using standardized contamination-free procedures. Concentrations of toxic and essential trace elements (Pb, Hg, Cd, As, Ni, Mn, Cu, Se, Tl, and Sb) were determined using atomic absorption spectrophotometry (AAS) following microwave-assisted acid digestion. Multivariate regression analyses, principal component analysis (PCA), and correlation analyses were performed to evaluate exposure patterns and associations with neonatal outcomes. All investigated trace elements were detected in meconium samples, indicating widespread prenatal exposure among the study population. Considerable inter-individual variability was observed across most analytes. Higher concentrations of several toxic elements, particularly Pb and Hg, were generally observed in samples from Damascus compared with those from Latakia.Sex-specific associations with neonatal outcomes were observed. Before correction for multiple comparisons, several trace elements were associated with birth weight in sex-stratified analyses. After false discovery rate correction, an inverse association between thallium concentrations and birth weight in female newborns remained statistically significant. PCA and correlation analyses suggested potential mixed exposure patterns, although specific exposure sources could not be identified. This study provides baseline biomonitoring data on prenatal exposure to toxic and essential trace elements among newborns in Syria. Trace elements were detected in all meconium samples, indicating widespread fetal exposure within the studied population. Sex-specific associations with neonatal outcomes were observed; however, only a limited number of associations remained statistically significant after correction for multiple testing, and the findings should therefore be interpreted cautiously.