A possible link between mineralogy of loess deposits and high incidence rate of esophageal cancer in Golestan province of Iran

Loess and loess-like deposits cover large areas of Golestan province of Iran, a well-known region in the world for its high incidence rate of esophageal cancer (EC). Despite numerous published works on the possible contributing factors for the observed high incidence rate, very little attention has been given so far to a possible link between the mineralogy of loess deposits in the region and EC incidence rate. This paper tries to investigate in a medical geology context a probable link between the mineralogical composition, grain size distribution, and surface morphology of constituent minerals in loess deposits of Golestan province, and the observed high incidence rate of EC. To achieve this end, loess samples from two districts with high incidence rate of EC, i.e., Dashlibroon and Maravehtappeh were collected, analyzed and compared with the low incidence control area (Gorgan). The results clearly indicate higher quartz and zircon minerals content in Dashlibroon and Maravehtappeh compared with Gorgan control area, revealing a probable link between direct and indirect ingestion of these abrading and lesionforming minerals with EC incidence rate in the area. Gradual decrease of the extent and thickness of loess deposits and resistant heavy minerals content from Maravehtappeh and Dashlibroon towards Gorgan (control area) further confirms the suggested link.