I went and looked this up, because it sounded horrible.

from https://www.billionoysterparty.org/oysterfarms

> Oyster farms travel to the Billion Oyster Party from across the country, bringing their unique oysters for you to try — and pair with your favorite beverages.

You don’t eat them until after water quality has improved if it’s that bad. You also test for certain types of bacteria certain times of year depending on location.

The biggest pollution is usually from run off and oysters eat nitrogen and phosphorus. Nitrogen causes algae growth, like red tide, which deals all kinds of havoc to ecosystems.