Thanks to Brilliant for supporting  this episode of SciShow.

Go to Brilliant.org/SciShow to learn how you can  take your STEM skills to the next level! [♪ INTRO] Let’s say you’re visiting an old town on vacation. You go to the fountain to grab  a sip of water.

Hm. Salty! Little did you know, that could  be cemetery-flavored water!

Yep! Buried bodies don’t  really keep to themselves. As organisms decompose, their  chemical and bacterial riches can leach into the ground and water,  reentering the environment in a natural but admittedly gross process.

And depending on several  factors, those juices can even be dangerous for the living. Thankfully, there are ways to avoid getting  a little too in touch with your ancestors. When bodies are buried in cemeteries,  they don’t just lie there.

Well, they do. But they also decompose,  releasing salt and other nutrients, like potassium, chlorine, sulfur, and nitrogen. And the areas around them can end  up pretty different chemically from soil or water farther away.

Studies everywhere from Holland to  Australia have found that decomposing bodies can create local salinity  plumes in the water near cemeteries. These are areas of higher  salt and ion concentration. And that happens because human  bodies release tons of ions, or charged molecules, as they break down.

Now, it’s nothing to be too worried about yet. These are relatively harmless ions that normally exist in your body and in our ecosystem. And as you move farther away from the  corpses, these ions become more diluted.

Different cemeteries also have  different conditions that make them more or less likely to contaminate  the nearby environment. For example, a cemetery with fine-grain soil and a deep water table helps prevent seepage. But under less ideal conditions, bodies  can release bacteria into the ground, and some infectious diseases  can still be transmitted even 400 meters away from the cemetery.

I’m talking about hepatitis, typhoid fever,  and a lot of other pretty dangerous stuff. And even bodies of people who were  healthy and buried in coffins can leach organisms like E. coli, Salmonella,  and Strep into the ground. Most of them will die with the host.

But some can live up to five years  after their host is long gone. Even the way that we choose  to care for our dead also affects the levels of chemicals  and diseases in a given location. The preservatives perfused  through the body by some cultures before burial can contaminate  the surrounding area.

In the past in the US, we’ve  used dangerous chemicals from arsenic to mercury in corpse preservation. These toxins can get  incorporated into our environment just like the ions and diseases. Now, it became illegal to  use arsenic and mercury in embalming fluid in the US  over a hundred years ago.

But they can stick around for quite a while, so areas near very old cemeteries might  still have contaminated groundwater. On top of the buried body itself, metal  coffins release more zinc, copper, and lead. And wooden coffins often release  preservatives used in varnishes.

So whatever is in your body, or  around your body, doesn’t stay in the cemetery after you’re buried. It’s  incorporated into the greater ecosystem. And it might not stick to  just the surrounding soil.

Those chemicals can leach into aquifers  and potentially reach rivers and oceans, spreading out even more. Cemeteries  built on islands have even been eroded, leading to bodies resurfacing completely. So today, some governments regulate where  cemeteries are placed so they’re not too close to water supplies used  for drinking or food production.

Planning and maintaining cemeteries  well and keeping them far from the community’s drinking water can help keep  people safe from potentially dangerous chemicals and keep a bad  taste out of their mouths. Thanks for watching SciShow! And thank you to Brilliant  for sponsoring this episode.

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If you’d like to try it out,  visit Brilliant.org/SciShow or click the link in the description. The first 200 people will get 20% off  Brilliant's annual premium subscription. [♪ OUTRO]