This paper provides some data on the chemical composition of the near-shore water and interstitial water within the splash zone in Bolshye Koty Bay (Southern Baikal). It has been found out that the content of many chemical elements varies significantly in the interstitial water on the splash zone. Maximum amounts of biophilic elements are registered on the coastal zone in July that is a most favourable period for decomposition of shore aggregates of detritus. The water is enriched by the elements released by mineralization of the aggregates of detritus on the shore, as well as by Al, Si, Fe, Mn, Ti, rare earth elements and others that are converted into soluble forms as a result of disintegration of the beach material by the products of detritus decomposition. A critical point in migration of macro- and microelements is near-shore algae bloom and death, life activity of invertebrates, concentrating a wide spectrum of chemical elements when alive and supplying them into the near-shore and splash zones after death.