Describe the ways in which water in sewage polluted lake and water from the sea are unsafe to drink

Sewage holds toxic microbes and contains a mixture of suspended impurities. When these impurities hit drinking water microorganisms begin to deteriorate the water, and uses up the dissolved oxygen with the microorganisms, making these water dangerous to drink from. Major impacts of this can include giardia, salmonella, cryptosporidium, and E. coli.