How do Windsor schools fare in the lead crisis?

Local results in line with provincial findings, say Kenneth D. Drouillard, R. Michael Mckay, John H. Hartig, Joel E. Gagnon and K.W. Michael Siu.

The release of lead testing results from a consortium of journalists from nine universities across Canada sheds important light onto the issue of lead in our drinking water. While lead concentrations have declined in the environment, it is still present in our aging drinking water infrastructure.

Lead is a suspected carcinogen and neurotoxin that can lower the IQ of young children. In March of 2011, Health Canada revised its lead risk assessment and in 2017 recommended a new drinking water standard of five parts per billion from the previous benchmark of 10 parts per billion. However, the five parts per billion standard has yet to be adopted by Ontario.

Ontario has one of the strongest drinking water and source water protection programs in the country enforced under its Clean Water Act. To find out how Windsor fares relative to the rest of the province, we examined the 20172018 Chief Drinking Water Inspector Annual Report.

Data submitted by schools and child care centres from Windsor and Essex were compared against provincewide data.

The 2017-18 Ontario drinking water quality test database contained lead test results from 131 schools and child-care centres from Windsor and Essex. While Ontario schools are mandated to perform both standing and flushed water samples, we focus on flushed water sample testing as this provides the best estimate of exposure given that most schools and child-care centres must flush their taps daily or weekly dependent on the age of their plumbing and previous lead testing results.

Windsor and Essex schools were generally similar to the rest of the province in lead testing. The median and 90th percentile lead concentration in Windsor and Essex school flushed water samples was one part per billion and 2.8 parts per billion while for the province it was one part per billion and 3.0 parts per billion, respectively. There were 15 test results (2.5 per cent) from Windsor and Essex schools that exceeded the 10 parts per billion standard that would have necessitated corrective actions be taken by the school that year. For the province, the prevalence of water quality standard exceedance was 2.4 per cent of samples. Some of the 15 failed test results came from the same school and when data were grouped by institution, there were eight schools in 2017-18 that required corrective actions. Most exceedances were within 50 per cent of the provincial water quality standard; however, test from one school were almost five times the standard and in another school nearly double.

The same test data were then compared to the more rigorous five parts per billion standard. For Windsor and Essex, there were 33 results (5.5 per cent of tests) exceeding the five parts per billion standard compared to 5.6 per cent of test results across the Province. There was also an increase in the number of schools that would have required corrective actions if the new drinking water standard was in place in 2017-18. In this case 15 schools, nearly double the institutions, would have been required to address lead in their drinking water under the newly recommended five parts per billion standard.

The revised lead drinking water standard recommended by Health Canada occurred because new scientific information becoming available since the previous benchmark was formulated nearly 30 years ago. It is possible, indeed likely, that in the future drinking water standards for lead will be decreased below five parts per billion as we continue to advance our understanding of risks of lead to early child development and health. In the meantime, we recommend early adoption of the new five parts per billion lead drinking water standard by provinces.

The data underscore that such a change will necessitate more aggressive investment by Ontario, municipalities and schools to change older plumbing and fixtures. Until these permanent solutions are implemented, daily flushing of taps and installation of certified lead filters will most likely continue to be used as interim corrective actions. Kenneth D. Drouillard, R. Michael Mckay and Joel E. Gagnon are professors, and John H. Hartig is a visiting scholar at the Great Lakes Institute for Environmental Research, University of Windsor; K.W. Michael Siu is a professor in the department of chemistry and biochemistry, University of Windsor, and a Fellow of the Royal Society of Canada.