Tungsten Alloy for Sports--Fishing(1)

According to my knowledge, tungsten alloy material is widly used for sprots, some of my friends who are interest in fishing, told me that fishing sinker, which is also called fishing weight, is usually made of tungsten alloy material.
They told me that tungsten should be the most suitbale material right now for fishing, as its small capacity but heacy density, also it is very environmental-friendly.
It is very intersting for me to know such things, for me, i am also fond of fishing, in the past, i usually use lead weight, but it seems that lead is not so environmental protective,therefore, i have tried some tungsten alloy fishing weight. It feels good. If the through hold is grindered soomthful enough, the line would be protected well. Or if you would require plastic inster for them.
Here attached some photos for the weights i used: