Association between lead in school drinking water systems and educational outcomes in Ontario, Canada

The purpose of this study is to use province-wide lead testing data from school drinking water systems and standardized educational assessments to investigate the association between lead exposure in schools and educational outcomes in Ontario, Canada for 2008-09 to 2015-16 school years.

Lead testing data were linked to assessment results in reading, writing, and mathematics from Ontario's Education Quality and Accountability Office and school neighborhood characteristics from the Ontario Marginalization Index. Sequential negative binomial models were used to estimate the relative risk of lower Education Quality and Accountability Office achievement in schools with lead exceedances in the preceding year, compared with those without.

Between 2008-09 and 2015-16, 78% of schools with Education Quality and Accountability Office scores were linked to lead testing results. In schools with lead exceedances, 8% more students failed to achieve the provincial standard for math (95% confidence interval (CI) = 1.07-1.09), 6% more students failed to achieve the provincial standard for reading (95% CI = 1.05-1.08), and 10% more students failed to achieve the provincial standard for writing (95% CI = 1.08-1.11). Associations of attenuated magnitude persisted after covariate adjustment.

Routinely collected lead testing data from school drinking water systems are associated with educational outcomes in the school-aged population and may present an opportunity for ongoing investigation of childhood lead exposures.