remains of a painting

I just scraped cleaned my painting bowl/palette and this is the remains of the whale painting. "Painting Ambergris" if you will.

I always enjoy the look of my leftover paint blobs. So chaotic and colourful...

but lately I've been wondering about the impacts of painting on the waste water system. Obviously I don't put stuff like this down the drain but I do rinse my brushes in the sink. It doesn't feel right but I don't know what I should be doing... Something to look into... I'm open to suggestions.

I added a touch more white around the whale this morning and took a couple more pictures in the daylight.

(click for bigness if you like)