Why the coffee mug can be TOXIC? With lead/cadmium!

Look here: Coffee mugs can be harmful to your health?

A mug can be toxic and leach harmful lead and cadmium. Coffee is actually acidic so it makes the mug leach lead or cadmium faster. Therefore, having a mug that doesn’t contain lead and cadmium is important  especially for a coffee drinker like myself. Unfortunately, so many mugs contain lead or cadmium. A study by the University of Plymouth in UK found 70% of glasses they tested (out of 72 products) contained lead and cadmium. That means most of the mugs out there may have lead or cadmium. Here I’d like to share with you how mugs can be toxic and what non toxic mugs are available. And it can help you to get a coffee mug that is non toxic and cadmium & lead-free.


Why the mug might be toxic? 


Mugs can be made with plastic, ceramic, porcelain, bone china or glass. Plastic is a hazardous material to begin with and very bad when mixed with heat, therefore, I wouldn’t choose the material especially for drinking hot beverages. Heat will increase the amount of toxins leaching into drinks faster.


Ceramic mugs have glazes and decorations that usually contain lead or cadmium. Lead is usually used to make glazes look shiny and smooth. Cadmium is often used to provide dishes bright colors. Lead glazes and decorations are also commonly used on porcelain or fine china. Since small traces of lead or cadmium is allowed in dinnerware and mugs sold in the United States, many mugs contain lead or cadmium. Whether they are plain white, colored or decorated, they all have a chance to contain lead or cadmium. FDA started testing for safety starting 1970, therefore, most vintage china will contain high levels of lead and cadmium. Even nowadays, some fine chinas contain lead and cadmium regardless of their color and decals. For Glass mugs, if they are colored, painted or have decal-type decorations on the surface, they will most likely contain lead or cadmium. (except leaded crystal which contains lead as an ingredient)


Acidic food or drinks will make these materials leach lead or cadmium easier and faster. Unfortunately, coffee which many people drink daily, sometimes several times a day is acidic. Therefore, it will not be good for a coffee drinker to drink coffee in a mug that contains lead or cadmium. Microwaving a mug that contains lead or cadmium will also make leaching of toxicants easier and faster.


How to choose a non-toxic mug?


In order to find out how much lead or cadmium is present in the mugs, each mug has to be tested. However, I don’t have the proper testing instrument and even if I do, I  am not going to test every mugs before I buy. Since any ceramic, porcelain or china mugs can contain lead or cadmium from their glaze, I like the mugs that are made of glass. Glass material normally does not contain glaze unless it has painted or decal-type decorations.


A study by the University of Plymouth in UK found lead and cadmium in both the paint and glaze of decoration on the outside of the glassware and around the rim. The lead concentrations ranged from about 40 to 400,000 parts per million (ppm), while cadmium ranged from about 300 to 70,000 ppm. That is a lot of lead and cadmium found on glasses!  The limit levels for the externally decorated lip area of drinking glass are 200 ppm and 800 ppm according to the US Office of Environmental Health Hazard Assessment. Therefore, avoid glasses with paints and decorations and go for the plain, clear glass material. I have listed non toxic glass mugs below.


Some mugs are made of borosilicate glass. Borosilicate glass has extreme resistance to severe temperature changes and thermal shock. Some glass mugs are insulated so you can keep the temperature of drink hot or cold for a long time.

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