SHAFAQNA – The Grand Ayatollah Makarem Shirazi answered a question about the range of the soil of Karbala.
Question: What is the range of the soil of Karbala?
The Grand Ayatollah Makarem: There are different narrations about this, in some 70 Zera’a is mentioned (each Zera’a is the distance between elbow to the end of the middle finger of the same hand), in others, 4 Meel (each Meel is equal to 4 Zera’a), and other said 5 Farsang (each Farsang is equal to 5.5 Kilometers). Maybe these refer to levels of the soil, and the Wajib precaution is that whatever is taken to be used, be close to the grave, especially when there are changes around the noble grave, some Torbah (soil) is obtained, and if the intention is to eat the soil for cure, it must be taken from around the grave.
Source: PERSIAN SHAFAQNA