Perchlorate exposure in Chinese primary children: Levels, potential health risks, and association with sexual development.

Perchlorate (ClO4-) is a ubiquitous endocrine-disrupting chemical commonly detected in daily environmental matrices, including drinking water, fruits, vegetables, and meat products. This contaminant disrupts thyroid and gonadal homeostasis, thereby disturbing endogenous hormone secretion. Growing public and scholarly concerns regarding the endocrine-disrupting potency of perchlorate have highlighted its plausible association with aberrant sexual maturation among pediatric populations. In this study, perchlorate, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and Malondialdehyde (MDA) were measured in urine samples of children with precocious puberty (PP) or early development (ED), and healthy controls in a tropical city, South China. The overall urinary perchlorate concentration across all enrolled children peaked at 304 ng/mL, and notably elevated perchlorate levels were identified in girls with ED (median: 9.35 ng/mL) relative to healthy controls (median: 6.32 ng/mL). The results of Molecular docking further demonstrated that the interaction of perchlorate with aromatase (Binding energy: -4.2 kcal/mol) may affect the synthesis of estrogen. The estimated daily intakes of perchlorate for most children (range: 0.0002 to 0.702 μg/kg/day) were lower than the value suggested by the US EAP (0.7 μg/kg/day), indicating low health risk from perchlorate exposure. Elevated body mass index was identified as a critical risk factor linked to abnormal pediatric sexual development, with statistical significance observed for PP (p < 0.05) and ED (p < 0.001). Regular consumption of red meat, as well as milk and dairy products, also significantly increased pediatric PP risk (all p < 0.05). Additionally, significantly positive correlations were observed in concentration levels between perchlorate and 8-OHdG or MDA (all p < 0.001), indicating that perchlorate may influence the degree of oxidative stress to a certain extent.