As the battery corrodes....
As the battery casing corrodes, chemicals leach into the soil and make their way into our water supply. Eventually they reach the ocean and harm our marine wildlife too. In fact, they adversely affect our entire ecosystem.
Batteries that make their way into our environment cause air, water, and soil pollution. Air pollution arrives in the form of greenhouse gas emissions when batteries undergo a photochemical reaction as they decompose in landfills. When harmful chemicals (including metals such as lead, manganese, nickel, mercury, and lithium) and acids from batteries find their way into the water supply, the animals and plants that thrive there get killed. Animals including humans that consume battery contaminated water and fish are jeopardizing their health and get fatal diseases like cancer. When these substances reach the soil, all detrimental effects relating to heavy metals are seen.