Firstly, this is NOT a horror movie (And who thought up the cannibalistic islanders?). The film is about the devastation that comes from the pollution of one the islands beaches with synthetic hormones.
The islanders, having been made to suspect that the physical and mental deformities they're suffering from are caused by generations of inbreeding, regard the coming of an environmentalist as a threat to their community. They hide the sick and try to make sure that nothing 'wrong' is found. The movie is about the struggle of an environmentalist to find out what's the matter with the island, and then the struggle to educate the population about the cause and possible solutions for the problems.
All in all not a bad environmental drama, reminds me a bit of the Minimata disaster in Japan. I give it a 7 out of 10, mainly for the atmosphere on the island and the balls it must have taken to make this film in '72.
