If you ever wondered why you should NEVER throw batteries away, well, here's your reason.
My grandfather recently passed away, and in the weeks following, my mother and I have the task of cleaning up and cleaning out his office. His filing system consisted of opening a drawer and dropping in whatever files and records he was holding, as well as the occasional golf ball or odd change. He also kept stacks of magazines, old bills, etc., variously piled on the floor or in filing cabinets. As the acting president of our small family business, he came in each day long enough to open the day's mail and make any calls to overdue accounts or business associates, as needed. Most days, if you blinked, you missed him.
So it makes sense that, after we moved to a new office building 10 or so years ago, anything he brought with him from the old office [and from the days when he worked a full day] might still be in the office, so many years later.
I was sorting through some things on shelves in his office and came across an unopened package of DD batteries, covered with a fine layer of dust. When I picked them up, I was rather horrified to notice that some of the contents of the batteries had managed to escape out of the bottom of the battery. Again, these were unopened and never used [or even touched after being purchased, apparently], so it could be assumed that this happens to all batteries at some point.
Batteries contain toxic materials, like lead and cadmium, as well as acid and valuable metals. According to one recycling website, "Mercury and mercury compounds in batteries are highly toxic to people, wildlife, and the environment. Health risks associated with mercury include kidney damage and genetic, neurological, and psychological disorders. Cadmium is a confirmed human carcinogen and is poisonous when ingested or inhaled."
There has never been a 100% leak-free landfill, so any potentially toxic material you throw away could wind up leaching into the earth and into the water you and I drink.
Recycle your batteries! If your city doesn't offer it, demand to know why. Demand that recycling sites be made available, not only for batteries but for glass, plastic, aluminum, paper, etc. In today's world there is no excuse for throwing away any material that can be reused. It also helps to reuse things like glass bottles before recycling them. Any glass bottle with a cap works well as a water bottle, without the creepy plastic chemicals getting into whatever you're drinking.
And buy rechargable batteries, while you're at it. I've been using the same 4 batteries in my camera for FIVE YEARS. Think of all the batteries, and money, I've saved myself.