ABSTRACT

There are three groups of microorganisms that may travel through porous geologic media: protozoa, bacteria, and viruses. These organisms differ greatly in size and survival in the environment. Each of these groups of organisms have members that are capable of causing disease (pathogenic) in humans and other mammals (Table 9.1). Although transport of bacteria is also important in bioremediation, this section will focus on transport of pathogens. In particular we will emphasize virus transport, since their small size makes them more likely to be transported through the vadose zone. Some Important Human Pathogens That May Be Transported Through the Vadose Zone

Microorganism and Size

Disease

Viruses (0.02–0.10 μm)

Adenoviruses

Respiratory disease

Polioviruses

Poliomyelitis

Echoviruses

Meningitis

Coxsackie viruses

Myocarditis, meningitis

Hepatitis A virus

Infectious hepatitis

Rotaviruses

Diarrhea

Bacteria (0.5–1.0 μm)

Campylobacter fetus

Diarrhea

Escherichia coli (pathogenic)

Diarrhea

Salmonella typhi

Typhoid fever

Shigella spp.

Bacillary dysentery

Vibrio cholerae

Cholera

Protozoans (1.0-12 μm)

Giardia lamblia

Diarrhea

Cryptosporidium spp.

Diarrhea