Association between organic micropollutants in tap water and human exposure and birth outcomes: Implications for environmental health in northern Puerto Rico

The presence of micropollutants in Puerto Rico's tap water, potentially linked to nearby Superfund sites, was hypothesized to contribute to the region's higher preterm birth rate than the US mainland. This study analyzed the presence of 175 micropollutants in tap water samples collected from participant households and evaluated their association with human exposure using 14 oxidative stress and inflammation biomarkers in urine samples collected from pregnant participants, and further with the subsequent birth outcome information. Notably, three out of four oxidative stress biomarkers consistently showed negative correlations with five micropollutant categories, highlighting the oxidative stress induced by these contaminants. For the ten selected inflammation-related biomarkers, two showed positive yet not significant correlations with the five categories of micro-pollutants and, only one biomarker (MMP1), an inflammation biomarker whose down-regulation was associated with pre-mature birth implications, showed significant negative correlation with industrial chemicals and pesticides. Interestingly, the detected urinary phthalate metabolites in pregnant women could not be linked with the two parent phthalates found in the tap water, suggesting that the two phthalates in tap water may not be the primary source of phthalate exposure to human body. Furthermore, hormones in tap water showed significant moderate-to-strong negative correlations with birth outcomes, raising specific health concerns for pregnant women in northern Puerto Rico. This is the first study to investigate the association among a wider spectrum of tap water micropollutants with pregnancy exposure and birth outcome in Puerto Rico and provide insights into water quality and associated human health impacts.