In Philadelphia, as in many cities across the country, the legally-required statement on the quality of water in our taps proclaims “Philadelphia’s water is safe and healthy to drink for most people.” The only exception, they claim, is people with “special health concerns,” like compromised immune systems. But sometimes we wonder how they know it’s safe, and then we look at the science, and when it comes to heavy metals, it’s very clear they don’t know.
The Case of Arsenic
Arsenic is considered one of the most dangerous compounds threatening the world water supply. Because it is common in nature, it commonly washes into and contaminates drinking water, especially after mining activities in which it is concentrated as part of extraction processes. Arsenic at levels considered toxic threaten the water supply of more than 100 million people, and the real truth is that it likely threatens many more of us.
Arsenic standard levels are established at 10 ppb (parts per billion). This is ostensibly a safe level for arsenic in tap water. However, new evidence suggests that even at this level arsenic poses numerous dangers. For example, research published in 2013 shows that pregnant and lactating mice consuming water with arsenic at the 10 ppb level experienced difficulties producing fats necessary to nourish their children. Their babies experienced significantly slower growth than mice consuming water with no arsenic.
Another study published in 2013 showed that water containing 10 ppb of arsenic could induce cancer formation in prostate cells, and was twice as likely to do so when combined with estrogen, which is not only found in drinking water, but is released from plastics and the lining of canned foods.
With this and other data, we have to conclude, along with the National Research Defense Council, that there is no safe level for arsenic in drinking water. The 10 ppb standard was put in place largely due to lobbying pressure, and needs to be re-examined.
The Case of Mercury
Mercury is another highly toxic heavy metal that we don’t know whether there is a safe level. We know the effects of high level, acute mercury exposure: brain damage and death. Most of our knowledge about the dangers of mercury point to these high levels of exposure, but we have not yet established a lower level boundary for mercury exposure.
Methylmercury is considered the most dangerous form of mercury. It is the heavy metal combined with an organic element, which makes it easier to absorb and concentrate in the body. Methylmercury is measured usually in terms of micrograms per gram (µg/g) of hair, because this is considered a reasonable measure of the amount of methylmercury concentrated in the body.
Fifty µg/g safe level of methylmercury exposure, but studies have shown that people experience effects long before this threshold is reached. Studies have shown that even at relatively low levels of exposure, people may experience a loss of color vision, contrast sensitivity, and peripheral vision. Research published in 2012 showed that children were more likely to suffer from ADHD if their parents were exposed to levels of mercury previously considered safe.
Worse, the safety standard for mercury in drinking water is for inorganic mercury, which is believed to be relatively inert and mostly a danger to the kidneys. But we now know that bacteria in our bodies can change inorganic mercury to the more dangerous methylmercury, though we don’t know how quickly or to what extent methylmercury exposure is due to this mechanism.
“Based on my experience with mercury amalgam fillings,” says Dr. Kenneth Siegel from Dental Excellence of Blue Bell, “I would be reluctant to say that any amount of mercury in water is safe. Amalgam fillings have also been considered safe because they contain the same inorganic mercury found in drinking water, but many patients report symptoms that point to mercury toxicity. There’s just too much about this that we don’t know to declare that a certain amount of mercury is safe.”
With the possibility that water safety standards are inadequate, we must take other measures to protect ourselves and our families.
Matthew Candalaria writes for Off-Topic Media. Thanks to Dr Ken Siegel for taking the time to speak with us.