Thursday, December 8, 2011

Use of water quality test kits in Haitian ecology conference

At both ecology conferences I taught about bacteria using the portable microbiology labs that Dr. Bob Metcalf of California State University developed for use in Africa. The kits detect both coliform bacteria that usually occur in the environment and do not cause human health risks, and a type of coliform called E. coli that come from human and livestock kaka (the universal term for poop).  One type of E. coli makes us sick, but even the presence of non-harmful E. coli indicates that our kaka is in the water and probably other things such as cholera and dysentery that makes us sick. Contaminated water needs to be boiled before drinking. It seems that people already treat their water, so I presented this as a way to track down sources of contamination. The coliform bacteria in the water sample will grow as red spots on the petri plates and make the water in the tubes turn yellow. If these coliform are E. coli from kaka, they will be blue on the plates and fluoresce when a black light is shone of the tubes. The tubes and plates need to be incubated for 12 hours the bacteria to grow. In lieu of an electric incubator one can incubate them against the body under the waistband.

I handed out 3 bags of 4 kits (plate + tube) to people at the first conference on the second day of the conference, then wizened up for the second conference at Riske de Cayahonde and handed them out the 1st day so that people could bring them back and I could help them interpret the results. These observations are from the 2nd conference (see pics). I showed three people how to use the kits (with the rest of the class watching), but didn’t have a spare plate to show for real how to put the water on the plates. That was a mistake – only one person got it right! I don’t know what the old man did – he had time to do only 2 of the tests and it looks like he just put a couple drops of water on the plates. The tubes were still clear which means he didn’t incubate anything. He also didn’t label anything. He later spoke up and commended the woman who did everything perfectly and said it’s a lesson in taking education seriously. The class gave her three rounds of applaud. Three people worked together on the third batch of kits. The water wasn’t distributed evenly on the plates so I don’t think they got enough water on it (1ml which is measured with the supplied pipette). But everything was labeled and incubated properly. Next time I need to color code the pairs of tubes and plates since I have difficulty reading the Haitian handwriting. Then at least I know how to pair up the tubes and plates even if I can’t figure out the writing.
Another thing that was difficult was seeing the fluorescence of the tubes with the black light. I didn’t realize that it needed to be very dark to see this. I put the tubes in a cardboard box and peeked in and could tell which tubes fluoresced, but it was too difficult to show this to the class. Next time I’ll use a black bag we can stick our heads in. (Also I didn’t try to explain fluorescence, I called it glowing).
The results are in the pictures of the white board. If the tube is clear and no bacteria grow on the plates, the water is sterile – none were like this of course. If the tube is yellow and the bacteria colonies on the plates are red, then there is coliform but not the E. coli kind. Four of the 8 water samples were like this. Two samples fluoresced but had no blue colonies, thus a moderate risk of getting sick from kaka-carried diseases. Two samples did not fluoresce but did have a couple blue colonies, also a moderate risk of getting sick from kaka carried diseases.
I will translate some of the instructions and interpretation of results into Creole for next year. People need to record the dat (date), lokasyon (location), if the tube turned jòn (yellow), if the colonies were ble (blue), and if this means a risk of maladi (illness). Non = no, wi = yes. Locations included sous (spring), gwo rivye (big river), and a ravin (ravine). Locations in the 2nd board are place names or descriptions: ti pye = little tree, not sure what the other two are. These kits are great tools for teaching about health and water quality, and I learned a lot about how to better structure the teaching to help people get better results.

1 comment:

  1. Bacteria strength level and testing analysis is really important for water bodies use for drinking.
    Groundwater Monitoring