Interview with Koji Tanida (second interview): About mercury
How is mercury currently used?
Some gold mining sites around the world utilize a conventional technique where alluvial gold and mercury are placed in a pan to make gold amalgam (an alloy), which is then heated with a burner, etc. to evaporate the mercury off and leave the gold behind.
This method is repeatedly used, resulting in mercury vapor diffusing as a gas into the air.
The mercury content in the air measured in those types of areas is overwhelmingly higher than that in living areas.
The mercury vapor found in these areas is inorganic and has not resulted in very much damage up to now to the people living there, however, once mercury enters any rivers in the ecosystem, it can result in a chain reaction in which it is absorbed by fish and becomes organic matter, and if the fish are then eaten by human beings, it can result in Minamata disease.
The governments of countries where mercury is emitted in that way find themselves caught in the dilemma of the need for countermeasures but the impossibility of ceasing mining gold: of course they realize it’s dangerous but consider it to be a matter of life and death for the people working in the gold mining industry because it is of vital support to their lives.
This is a difficult problem to solve and I think we will need to develop a mercury-free method of mining gold and provide the people living in those areas with that information.
Once emitted into the air, mercury diffuses on a global scale. The Minamata Convention raised the gold mining method that utilizes mercury as being an important issue.
I guess you must have always had interest in other areas as an engineer but what has made you continue to engage in mercury matters up to now?
My academic major was physics but I wasn’t a very good student.
I, of course, had heard of mercury but had no special interest in it.
I joined this company and was assigned to the department that had just started developing mercury analyzers, and hence I was involved with mercury as my primary task, which has continued to this day.
As I stated earlier I never actually wished to work with mercury. Usually students only have limited opportunities to do experimental work, which means, I think, that their academy background, i.e. what subjects they majored in or studied, does not really matter.
Some young employees joined us because they had used mercury analyzers made by Nippon Instruments to take environment measurements in their laboratories during their schooldays, through which they grew interested in mercury and wished to continue doing that type of research.
Tell us about your qualifications as a certified measurer and a working environment measurement expert.
One of our future business strategies includes a certification business, which will involve analysis, and hence I acquired a certified measurer qualification.
Any requests for analysis make this qualification necessary in that we need to submit measurement certificates as official measurement results, and therefore I studied for the qualification little by little in my spare time during business trips or at other times and eventually acquired the qualification.
I was also qualified as a working environment measurement expert, as working environment measurements require a basic design to be made by a person who has qualified as an expert on the field.
Once again I was not a very good student; my practical training instructor had to warn me by stating, “Yes, you managed to pass the written examination but your performance was not really something you can take much pride in.”
Do you think about mercury in your daily life?
Yes, I do.
My attention is automatically drawn to the word “mercury” whenever it is mentioned on TV programs or in the newspaper.
In a way it is an occupational hazard.
I handle mercury almost everyday at work so I have to identify the mercury level in my body by occasionally sampling my hair.
One day I measured the mercury level in the hair of my child and discovered that he (she) had basically the same level of mercury as me.
That proved that the level of mercury of my hair was a reflection of my eating habits and my genetic factors, and that there were no signs of any adverse effects from my job involving mercury, which led me to a feeling of relief.
It is easy to measure the level of mercury in hair. When I visit overseas customers to deliver mercury analyzers, I usually explain the products and the measuring method to them, and then often offer to “measure the mercury level in their hair.”
At first, they hesitate to accept the offer and when the mercury level as a measured result is revealed, they often look rather anxious.
I then, however, measure the mercury level in my own hair and show how it is much higher than their level. They can then see, in spite of the higher mercury content, that I am healthy and in a good shape, and feel relieved.
I demonstrate this because I know Japanese people eat fish species that are quite high in the food chain, for example, tuna and bonito, and our mercury levels are generally higher than people in other countries.
Talking about bonito, you eat probably Tataki of bonito with garlic as a garnish, don’t you?
Garlic contains selenium, which has detoxifying effect, captures mercury in the human body and discharges it out of the body.
I wondered if people in former days ate bonito with garlic because they knew its effect through life experience. I was impressed with their wisdom.
The Minamata Convention was adopted in 2013. Has that brought about any changes?
Nothing significant yet, but I am fairly certain we have received more inquiries than before.
And we have more opportunities in various ways to provide information as a maker that specializes in mercury analyzers.
People in other countries used to say “NIC? What’s that?” in the past, but now I feel the name “Nippon Instruments Corporation” is gradually gaining recognition.
The majority of average citizens do not know anything about the Minamata Convention, but the effort to reduce mercury throughout the world is a very meaningful initiative and I think things will be safer and better for everyone.