Whenever you eat shellfish you’re taking a chance... They can be contaminated with toxins because they are filter feeders and they mostly eat fish sh*t.
What did you think was going to happen?
There are outbreaks of sickness and deaths associated with eating shellfish on a yearly basis.
I remember a local (Oregon) girl talking a midfde-aged Sacramento woman through her first fried oyster....“That green stuff is kelp. Oysters love kelp.” ...and I’m thinking “Oysters love raw sewage, if they can get it.”