Fishing objects out of a river - AIBU?

[Saraleast]

So my partner took his son and daughter from previous relationship to a river that runs through some land he has been landscaping for a few weeks to show them what work he has done. When they got back - DP told me that his daughter (who is 4) wanted to fish out a ball (it was deflated and in my opinion just a bit of old junk). DP let her bring it home and now it's sat in the kitchen - I questioned why bring it home - he said " she really wanted it"
I can't understand why on earth with all the germs etc he would want to teach her it's ok to fish things out of a dirty old river?
Or am I just over thinking it? Meanwhile I have this dirty deflated ball in the kitchen on the side.
WWYD?

It's fine. As long as she washes her hands before she eats. Playing and getting dirty is good for kids. I think it's kind of sweet that your daughter thinks the ball is a treasure - the polar opposite of so many spoiled children who just want brand name everything.

Mine would want to do the same, so long as it was safe I'd probably let em. Then make them wash their hands!

Is it that big a deal? Put ball in garden. Hose it down or bucket of hot soapy water. Leave ball in garden. When his daughter tires of it, bin it.

I think its ok. Second the poster above who said that kids need to be a bit dirty in order to build up immunity. Just get her to wash her hands before eating etc.

Also maybe make it an 'outside toy' 😂