At least according to an NBER working paper Di Salfro and Hill (2023). The summary is as follows:
Previous U.S. research has found negative health impacts when pollution triggers regulatory violations. An important question is whether levels of pollution that do not trigger health violations can affect health. We used Pennsylvania’s drinking water sampling results data to examine the impact of drinking water contamination in community water systems on birth outcomes. We created an overall water quality index and a reproductive health-specific index. We focus on the impact of water contamination on newborns who do not suffer regulatory violations. Our most stringent specification employs maternal fixed effects and finds that a change in water pollution from the 10th to the 90th percentile (among births not subject to regulatory violations) increases low birthweight and preterm birth by 12% An increase of 17%.
NBER Health Notices There is also a more detailed summary.
