STORY 8: "Hikaru Meets Mr. Yokoo again"

So, why is lead-free solder necessary?

Let me see. It may be related to an environmental problem. Also, it is related to water, specifically drinking water, because solder is not supposed to be ingested.

You really understood. Yes, in this case, the problem is acid rain.

Acid rain?

Destroyed and wasted electric products are thrown away and buried under the ground as a matter of course. When they are exposed to acid rain, lead contained in solder melts away and it is mixed with underground water.

Then, underground water is taken into the body as drinking water, isn't it?

That's right. Currently, various types of lead-free solder are used. But, individual types of solder have both advantages and disadvantages. It has not been used as commonly as tin-lead solder. Some of them have been put into practical use, but lead-free solder still has too many problems to be used commonly.

I see? But, since this problem is related to the human body, it must be solved anyway.
Only lead is regarded as a bad element, but the problem is also related to acid rain and the waste P.W.B. disposal method, I think.

That's right. At present, governmental controls such as the Electric Household Appliance Recycling Law are in effect and individual manufacturers are studying waste P.W.B. disposal methods.

Individuals must consider environmental problems more seriously.

Yes. You understand, Takeru!

You called me by an incorrect name on purpose, didn't you?

Ha-ha-ha-ha-ha (Laughing)