Final answer:
The two areas with the most fecal coliform can be determined by comparing the number of tubes showing growth in lactose broth across different sites after inoculating with water samples at various dilutions. The presence of fecal coliforms is an indicator of fecal contamination.
Step-by-step explanation:
To determine which two areas have the most fecal coliform, one would need to compare the results of chemical analyses for the presence of these bacteria across the different sites. Since fecal coliforms like E. coli are indicators of fecal contamination in the environment, finding the areas with the highest concentration can identify the sites with potentially the heaviest fecal pollution.
The number of tubes showing growth in a dilution series indicates the probable number of bacteria per volume of water. For the most accurate comparison, you would analyze the results for each site in the same manner as the example provided, inoculating lactose broth tubes with different dilutions of the water samples and checking for the pH indicator color change from red to yellow.
After incubation, you would compare the number of tubes showing growth at each dilution across all the sites. The sites with the highest number of positive tubes would indicate the highest concentration of fecal coliforms in the water samples.