A dolphin named Star
(Book)

Seaside Sanctuary Marine Wildlife Refuge in South Carolina has a wild pen which is supposed to be healthier for the marine animals brought there, but the three new dolphins are getting sick and no one can explain why; Elsa Roth, whose parents work at the sanctuary, is convinced that a local chemical plant is to blame, but since the water tests do not show contamination she is having trouble getting the adults to believe her--and if she is going to save a dolphin called Star she will have to find some way to prove her theory.