Salt is essential for life on Earth. It has been used by humans for thousands of years, from food preservation to being a form of currency. While salt is necessary for human health, too much salt or salt in the wrong place can harm or even kill almost any living organism on the planet.
Salt can also have negative impacts on the environment. For example, salt is toxic and lethal to aquatic life, pollutes drinking water sources, and damages infrastructure when there is too much of it in the environment.