In polluted environments, dolphins gradually accumulated toxins in their body fat, and the larger the dolphin the more accumulated toxin it can tolerate. Nearly 80 percent of the toxins a female dolphin has accumulated pass into the fat-rich milk her nursing calf ingests. Ttherefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida' s Gulf Coast is probably the result of their being poisoned by their mother' s milk.
The statement 'The rate at which adult dolphins living in the waters along Florida's Gulf Coast accumulate toxins is no higher than that of adult dolphins in comparably polluted waters elsewhere' most strengthens the argument.