שאלה | Does the presence of E. coli in a water sample signify a public health risk?

Does the presence of E. coli in a water sample signify a public health risk?

		The presence of E. coli in a water sample indicates that there are protozoan pathogens in the water; therefore, it definitely signifies a public health risk.
		The presence of E. coli in a water sample signifies a major risk to public health since most E. coli strains are pathogenic.
		E. coli is a non-pathogenic bacterium found in the digestive system of healthy people, and thus, its presence in a water sample does not signify any risk to public health.
		Not necessarily, however, E. coli generally indicates fecal contamination and, thus, a possible health risk.