GIS-based source identification and apportionment of diffuse water pollution: Perfluorinated compound pollution in the Tokyo Bay basin

► A GIS-based approach for PFC source identification was developed. ► Spatially distributed pollution factors of PFCs were evaluated by the method. ► Arterial traffic area was determined as one of the contributors of PFOS pollution. ► Contribution of the nonpoint source in PFOS was comparable to that of point sources.