Fig. 13From: Existing evidence related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones: a systematic mapThe red ellipse shows which part of the system that is in focus in studies performed in the vadose zone, in the natural soil environment. The red, dashed line indicates the limits of the complete natural soil system between facility and recipient, that is, the system of primary interestBack to article page