Explain how does:

the algal bloom eventually choke the water body in an industrial area?

)Biomagnification refers to the increase in concentration of the toxic waste at successive tropic levels. Biomagnifications of DDT in an aquatic food chain causes the increase in concentration of DDT at successive tropic levels. 

High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking, eventually causing decline in bird populations.