Which substance is largely removed by the combined effects of primary and secondary wastewater treatment? 

A)  toxic metals and synthetic organic chemicals 
B)  radioactive isotopes 
C)  organic oxygen-demanding wastes 
D)  organic pesticides

Wastewater Treatment

The process of removing contaminants from wastewater to make it safe for release into the environment or for reuse.

Toxic Metals

Toxic metals are elements like lead, mercury, arsenic, and cadmium that are poisonous even at low concentrations, posing serious health risks when they accumulate in the body.

Organic Pesticides

Pesticides derived from natural sources, used in agriculture to control pests without synthetic chemicals, aiming for environmental friendliness and sustainability.