Are there not issues with all of the, ahem, crap we eat? Apex predators accumulate high concentrations of pollutants (Silent Spring and all), and I imagine that

Are there not issues with all of the, ahem, crap we eat? Apex predators accumulate high concentrations of pollutants (Silent Spring and all), and I imagine that closing the loop by using human poo to fertilize crops for human consumption would only worsen this issue.