Environmental metal exposure and autism spectrum disorder: spatial analysis of exposure patterns and associated risk among children in Alabama.

Autism spectrum disorder (ASD) is a neurodevelopmental condition with increasing rates of diagnosis and potential links to environmental exposures. Metals are known neurotoxicants that may exacerbate ASD symptom presentation. Our study focused on children aged 3-10 years clinically diagnosed with ASD who have lived in Alabama since birth. Spatial analysis assessed metal distribution and clustering patterns, and Spearman correlation was used to evaluate associations between air toxic metals and ASD symptom presentation. Spatial analysis of airborne metals across Alabama showed considerable spatial variability and hot spots, mostly in central Alabama and surrounding counties. ASD symptom presentation showed moderate positive correlation with cadmium, chromium, and lead, weak positive correlation with manganese, and weak negative correlation with mercury. Proximity and statistical analysis showed 73% of the participants lived within 5 km of an industrial site; those living more than 10 km away had much lower ASD scores, and proximity was a strong predictor of ASD symptoms. Our findings show that children in Alabama may be exposed to multiple air toxic metals at different exposure windows, and industrial emissions and residential proximity to pollution sources are potential environmental contributors to increased ASD symptom presentation.