1.   Beryllium, a naturally occurring metal, is used to make components and alloys for car ignition systems, computers, spacecraft and nuclear bombs.

2.   Mercury, a naturally occurring metal, is also released by burning trash or coal.

3.   A naturally occurring metal, mercury accumulates in fish and becomes more concentrated as it moves up the food chain.

4.   A naturally occurring metal, mercury is a persistent pollutant that accumulates in fish and becomes more concentrated as it moves up the food chain.