Nitrates in your Water
by Irene Novaczek
Many islanders had the opportunity recently to take their water into a free clinic to have it tested for nitrates. In my village of Breadalbane, nitrate levels varied widely, from less than 1 ppm up to a high of just over 8 ppm. All samples were declared to be below water quality guidelines for drinking water and therefore “safe”. But what does the wide variation mean?
The only people who had nitrate levels less than 2—what could be considered uncontaminated, background levels—were living in the woods. People whose homes were adjacent to actively farmed land commonly had nitrate levels in the range of 3-6 ppm. Some folk in the village, where everyone is on well water and each home has its own septic field, had the highest nitrate levels.
Scientists generally agree that once you approach a level of 3, your water is being contaminated by some unnatural source of nitrogen. The sources relevant on PEI are 1) human sewage—generally leakage from septic fields or poorly maintained septic tanks; 2) animal manure—either from intensive manure spreading on fields, or concentrated patches of manure in piles or in feedlots, or a leaking manure storage tank; or 3) chemical fertilizers spread on cropland. A slightly elevated nitrate level may also be caused by rotting leaves or bugs, where your well is poorly designed or not well maintained, and allows such things to get into your water.
Nitrate all by itself is not a danger to human health until it gets above 10 ppm. At that point it can interfere with the developm ent of fetuses and young babies. There are parts of PEI
where nitrates exceed 10 ppm. Women of childbearing age, pregnant women and babies should not be drinking such water, just on account of the nitrates alone.
Everyone whose nitrate level is above 3 needs to recognize that they are drinking water that is contaminated by something—fertilizers, manure or sewage—and should take the time to consider which of these three is most likely. If you think sewage is a possible influence you should definitely get your water tested for E. coli bacteria, because this can make you either acutely or chronically ill. Sewage contamination can also involve viruses, pharmaceutical drugs and various toxins that people throw down their toilets and drains. Use an clean source of drinking water until you get the underlying problem solved.
If you are close to a source of concentrated manure, E coli is again a risk and a bacterial test is in order.
If you are within a few hundred metres of a chemically fertilized potato field or blueberry crop, that may be the source of your contamination. The PEI government’s1999WaterQualityreport showed that between 10% and 30% of samples taken from wells close to potato and blueberry fields had traces of two or more pesticides as well as elevated nitrates. Getting water tested for pesticides is very expensive and you have to know what chemicals you are looking for. Even if you do find out actual numbers, there may be no sure way of removing trace contaminants using any commercially available filter system.
The question is: should you be worried about trace pesticide contamination? After all, we are surrounded by, breathe, eat, and drink traces of toxic chemicals every day. Many are man-made but some are also naturally occurring, and humans seem to have survived, so far.
To get an answer to the question: should we worry? I undertook an examination of scientific studies on water quality, and this is what I found. Some interesting reports on the health effects of a combination of nitrates and traces of pesticides have been published, starting in the 1990s. For the most part, the scientists involved have not followed up with further studies, and similar studies are rarely done by anyone else. If one was paranoid, one could speculate that scientists who make chemical companies look bad lose their research support or fail to get published.
In general, you can find studies that support either side of any issue, simply because people ask different questions, use different equipment and methods, and are working on water with different characteristics. Also, the test animals—whether human, mice or other—will inevitably respond differently to whatever is being tested according to their weight, health, age, and other risk factors. You can count up the number of publications on each side of the argument and believe the majority, or look for signs that over
time, scientists are coming to some consensus. But that will only work if legitimate scientists have free access to funding and are not punished for unpopular results.
I have noted that studies on the health effects of pesticides in water that are funded by pesticide manufactur- ers are unanimous in saying that there is no problem. Government studies often focus on just one pesticide at a time. Very low concentrations (ppb) of any single pesticide, administered over the short term, can generally be shown to have no negative impact. Such studies support what we are generally told by government agencies: that the parts per billion contamination of our water with any given pesticide is nothing to worry about. Large scale demo- graphic studies, where researchers try to find relationships between average water quality on a broad scale and population health statistics, usually come up with nothing conclusive. Where two or more chemicals are present in water, some studies report unexpected effects because certain chemicals can make others more potent. Few studies throw nitrates into the mix, but depending on the combination of other chemicals present, it seems that trouble may ensue.
In one study in Idaho, for example—performed by university based scientists and published in a reputable, peer-reviewed journal—scientists had women drink their own, slightly contaminated water and then did various tests on their physiological response. They concluded that the Idaho water—which resembled ours in having elevated nitrates with mixtures of pesticides at ppb concentra- tions—had various negative effects on hormone levels and the immune system. The researchers concluded that problems such as attention deficit disorder, thyroid dysfunc- tion, chronic fatigue and weakened resistance to disease might result in some people who drank this water over the long term. I found this interesting because I have noted what seem to be very high rates of ADD in children as well as very common thyroid problems on PEI. Also, the particu- lar pesticides that were tested in the Idaho study are ones commonly used on PEI, and these have been found in our rivers as well as in well water. Drinking such water would not necessarily mean problems for everyone. Some people are stronger and more resistant to chemical contaminants. The very young and very old, and people weakened by other diseases are often the most vulnerable to any kind of contaminant.
In conclusion, I would encourage people to get their water tested for nitrates. If your results are above 3 ppm, consider where it may be coming from. If manure or septic contamination is a possibility, get your bacterial counts looked at, especially the E coli. If you think it could be chemical fertilizers, check whether the farm near you also uses pesticides. If so, and if your well is within 100 m of the field, you may also have very small concentrations of one or more pesticides in your water. This may not be causing you any problems at all, but if you have small children or an elder in your home, or if a family member has an immune system, thyroid or behavioural problem, it would make sense to find an alternate source of drinking water.