Most batteries—regardless of type—contain toxic chemicals. Think cadmium, lead, lithium, or sulfuric acid. If your old batteries end up in a landfill, pollutants like these can leak out and contaminate groundwater, damage fragile ecosystems, and potentially make their way into the food chain.
Recycle your old batteries https://www.consumerreports.org/home-garden/recycling/yes-you-need-to-recycle-your-old-batteries-a5385943645/