P3.E084: A Scoping Review Risk Assessment of the Ingestion of Chemical Contaminants in North American Urban Snow

Background: Children living in cold climates commonly eat snow. Unfortunately, the unique physical properties of snow, such as its porosity and high surface area, make it an efficient scavenger of pollutants. Childhood chemical exposures may increase the risk of adverse health outcomes later in life. Snow is an under-studied source of possible childhood chemical exposures in cold climates, because while there exist data on the chemical contaminants in urban snow these data have never been collated into a unified risk assessment.

Methods: We performed a scoping review of chemical contamination in urban North American snowbanks to illustrate what chemical exposure risk the average urban North American child faces when ingesting snow. When applicable, the results were compared to Health Canada (HC), United States Environmental Protection Agency (US EPA), and World Health Organization (WHO) drinking water guidelines.

Results: 132 pollutants were detected in snow across Canada and the United States across a wide variety of chemical classes. Concentrations of aluminum, arsenic, benzene, benzo[a]pyrene, lead, and manganese in snow exceeded the limits set by at least one of the guidelines, as displayed in Figure 1. Distance from point sources of pollution strongly impacted snow contamination levels, as displayed in Figure 2.

Conclusion: Whether snow is safe to ingest depends significantly on local environmental conditions, and while for some children it may be safe to consume snow, others could unknowingly be exposed to high levels of contaminants with known deleterious health impacts. These findings have significant environmental justice implications for children living and playing in polluted areas.