Mordants get a bad wrap in the natural dye world. Harmful mordants such as, Tin, Copper and Chromium dominate the discussion while others such as Iron and Alum go unnoticed. Both Alum and Iron are considered safe and when used and treated correctly, they cause no harmful impact to human health or the environment.  

Both Iron and Alum are approved for use under GOTS, OEKO-TEX, REACH.

Alum

We use potassium alum. Potassium alum is a naturally occurring mineral salt found in the Earth [1]. Potassium alum is used in some deodorants (Tom's of Maine), pickling recipes and commercial baking powder [2]. In a few cases, potassium alum has been considered a skin irritant [3] however, little evidence exists when alum is applied to fabric. 

When treated at a wastewater treatment plant, potassium alum does not present any danger to human health or the environment. It is water soluble and very little of the metal remains after treatment. Well below the regulated amount for drinking water. Lastly, the effects on plant life and the environment is considered minimal to none. Soil already contains potassium alum and studies have shown no effect of small increases in potassium alum [5, 6].

Side Note: All wastewater at Soluna Collective is required to be treated at a wastewater treatment plant.

Iron

In the dyeing process, iron comes from the boiling of natural dyes in an iron pot. Similar to a cast iron skillet, small traces of iron are transferred into the solution.

Iron is essential for human life. Iron gives hemoglobin the ability to bind with oxygen [7]. Without this, our red blood cells would quickly die. Because the body can absorb iron, it is considered a toxin. You can overdose on iron at high doses and when taken orally [8]. Children have overdosed on adult iron supplements. It should be noted, many adults take iron supplements and is considered completely safe. We found no results of harmful impact to humans when iron is used in fabric. 

When treated at a wastewater treatment plant, iron does not present any danger to human health or the environment. It is easy to remove through filtration and oxidation [9]. Most all drinking water contains small traces of iron and during drinking water preparation, iron is removed through similar processes as mentioned above [10].

Side Note: All wastewater at Soluna Collective is required to be treated at a wastewater treatment plant.

Questions

If you have any questions, please feel free to reach out. We love questions!