Coliforms … friend or foe

I have already mentioned that our domestic water supply is drawn from a surface spring. Having been raised in the city, this fact had been perhaps the most significant hurdle between me and rural living. I remember thinking .. water doesn’t come from the ground .. in order for it to be safe it must emanate from pipes .. right?

We recently had our water tested (see posts about the Marcellus gas shale industry) and can report that the results were well within recommended levels for things like iron, sodium, and sulfates as well as for compounds of particular concern (such as arsenic, barium, strontium, and methane for example) when fracking is occurring in your neighborhood. The test parameters which fell outside of recommended levels were those for total coliforms and fecal coliforms. I’m sure that anyone who reads this  is now aghast .. positive for coliforms! Take a deep breath. Coliforms are gram-negative bacteria found ubiquitously in water, soils, on plants, and in the digestive systems of mostly warm-blooded animals. Although a number of these may cause serious human disease, most comprise part of the normal (human) bacterial flora and are considered opportunistic pathogens; that is, they cause disease when host conditions are ripe to do so. The presence of coliform bacteria does not necessarily indicate that your water is unsafe; its presence however may indicate that other, potentially pathogenic, organisms may be around. If you look into our spring house you will see lots of little critters (mostly pill bugs, centipedes, and spiders) crawling about its walls. If you peer into the reservoir itself you will see a number of  salamanders and newts darting about. We were told by pervious owners of the farm that they used to put a trout or two into the spring each year. They’d allow these to feed and to fatten until it was time to harvest. We suppose the trout also acted as the proverbial Canary in the Coal Mine and would be a real-time indicator of water quality as well. If you look around the spring house the surrounding wood is busy with the traffic of a variety of wildlife including birds, domestic dogs and cats, deer, raccoons, possums, and mice; and more unpredictably bobcats, bear, porcupine, and foxes. The place is teaming with the activity of warm-blooded animals (which harbor and deposit fecal coliforms). To discover the presence of coliforms in our spring should come as no surprise – we expect them to be there. It is wrong to conclude that the presence of these organisms makes the water unfit for consumption. For years we drew our domestic water straight from the spring. To put those of you who might be concerned about the presence of coliform bacteria, pathogenic or not, you will be glad to know that we now have a UV filter in place which instantaneously kills any biologically active material in our incoming water stream including bacteria, viruses, and protists such as Cryptosporidium and Giardia. Our water is excellent. It is soft, clear, cold, and delicious. We are grateful for it – coliforms and all.

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