Spatial analysis of discarded needles and dropbox locations in Calgary, Canada


  • Abreham Mekonnen Faculty of Health Sciences, University of Lethbridge
  • Em M. Pijl Faculty of Health Sciences, University of Manitoba


Public injection, Overdose, Substance misuse, Improperly discarded needles, Homelessness, Supervised consumption services (SCS), Geographic information systems, COVID-19


Concomitant with the rise in the number of people who inject drugs has been an increase in unsafely discarded needles and injection debris. While the scholarly literature indicates that harm reduction programs reduce needle debris, the news media often report otherwise. Using geographic information systems (GIS) software ArcGIS Desktop 10.8 (Esri 2020), we analyzed geospatial data pertaining to needle debris in Calgary (Canada), correlating debris with available needle dropboxes, outreach education, overdoses, and changes over the COVID pandemic. Needle debris was most dense in two central neighbourhoods: Beltline and Downtown Commercial Core. The city’s central neighbourhoods contributed to 83% of all needle discards, which accounted for 73% of discrete locations. Additionally, 51% of discarded needles were collected from the Beltline (40%) and Downtown Commercial Core (11%) neighbourhoods, accounting for 85% of clusters and 71% of hotspots. Overdoses were positively correlated with needle debris. COVID-19 pandemic restrictions were linked to a spike in the number of discards. Needle debris is a complex social, environmental and public health issue that requires a multifaceted approach. GIS mapping is a powerful tool that can locate hotspots so that resources can be deployed.