What does MBD have to do with plastic bowls? I keep small/baby turtles in bowls or shoe boxes until they get around 3 inches. My friend just hatched out some common musk that would drown in a tank. As long as you change the water daily, let sunlight get to the turtle & have a good diet then there is no problem with bowls. I have 3 sliders & some maps that are 5-6 inches that lived in a bowl the 1st 2 yrs. of their lives.