Spraying of $DDT$ on crops produces pollution of ...

Which of the following statements regarding pollutants is correct?

$A$: Ecological sanitation is a sustainable system for handling human excreta.
$R$: It is a practical and hygienic method of using dry composting toilets.

$A$: $A$ few toxic substances often present in industrial waste waters undergo biological magnification.
$R$: $A$ toxic substance can easily be metabolised or excreted by an organism.

Assertion: Eutrophication shows an increase in productivity in water.
Reason: With increasing eutrophication,the diversity of the phytoplankton increases.

Who discovered Polyblend?