Water Sampling and Testing

By Amanda M. Icazatti-Burtell

Seventy percent of our body is composed of water and three quarters of the Earth is water. Therefore, water is very important and necessary to all human and life activity. Without it life wouldn’t be possible on Earth.

Unfortunately, a number of potentially harmful and dangerous chemicals make their way into water sources. These contamination events are produced by industries, agriculture (i.e. fertilizers, insecticide, etc), and even atmospheric emissions. Since all living organism consume water, all these contaminants that accumulate within it affect us enormously. The consumption of contaminated water can lead to serious health issues that can affect the way our body responds.

For this experiment, 100-mL water samples were taken from different parts of Puerto Rico. The samples were tested for coliphages, a type of bacteriophage that infects Escherichia coli. The process consisted of mixing the water sample with 2-mL of the host bacteria (E. Coli) and medium broth, which supplied all the nutrients needed for the development of the host bacteria. It was important to work very near the burner to prevent contamination of the experiment ( Aseptic technique). After the mixture was prepared it was distributed equitably into ten (10) petri dishes. After fifteen (15) minutes of agar solidification, petri dishes were incubated for 24 hours in a 37˚C incubator. After the hours of incubation, no plaques were found in any petri dishes. Therefore, a negative result for the present of phages was obtained. Even though it can be inferred that the water is safe for usage, exist the possibility that something could went wrong in the process of the experiment, since no student came with a positive result.

A positive result for these colipaghes would indicate that there is animal feces material within the water source and therefore, the water source is contaminated and is not safe for any use or consumption. In addition, it would indicate the presence of other active bacteria such as Salmonella, which are very harmful to health.