Chlorination of untreated wastewater is typically NOT effective for which of the following?

Chlorination of untreated wastewater is typically not effective for certain pathogens, particularly those that can form resistant structures or are shielded from chlorine's disinfecting action.

Entamoeba histolytica and Giardia lamblia are both protozoan pathogens that can exist in the environment in cyst form, which provides a protective barrier against disinfection processes, including chlorine treatment. While chlorine can kill many bacteria and viruses, its efficacy against protozoan cysts can be significantly limited.

Tapeworm eggs, which belong to a class of helminths, are similarly resistant to chlorination due to their tough outer shells. These eggs can survive standard disinfection processes, rendering chlorination ineffective for their elimination as well.

The collective resistance of entamoeba cysts, giardia cysts, and tapeworm eggs to chlorination underscores the inadequacy of this method for ensuring the complete disinfection of untreated wastewater containing these pathogens. Thus, it is accurate to say that chlorination is typically not effective for all these agents.