In minamata, japan, cats, and then people began to develop loss of motor control, among other symptoms. eventually children were being born with a 'disease' which was later identified as mercury poisoning. testing showed low levels of mercury, an average of 20 ppm in shellfish. mercury waste was being absorbed by plants and working its way through the food chain to the shell fish and large fish that were the town's main source of protein. high concentrations of mercury were found in the tissues of cats and people, up to 145 ppm. the high levels in cats and people demonstrates