Like iron, copper is an essential element in a person’s diet. Too much copper, however, can cause health problems, as it accumulates primarily in the liver and kidneys. Like the current issue with lead in the water supply in Flint, Michigan, copper in drinking water can come from corrosion of copper pipes. Flushing the tap for 30 to 45 seconds can reduce the copper that has accumulated when the plumbing is not in use. Reverse osmosis or ion exchange are effective at reducing excessive copper from water.
The recent events in Flint, Michigan have raised awareness of problems with our nation’s aging infrastructure and the increasing costs of providing safe drinking water. What is often forgotten is that lead can also be found in private wells. Very few, if any, states require monitoring for lead in private wells. As more people leave the regulated environments of cities and towns looking for their own Redoubts, they need to be aware they alone are responsible for determining the potability of their water. Many small towns across the nation have a legacy of mining, and groundwater may have naturally high levels of many heavy metals. Health effects in children from exposure to lead are well documented, resulting in behavior and learning problems, lower IQ, and slowed growth. In pregnant women, lead can cross the placental barrier, exposing the fetus to lead. This can result in reduced growth of the fetus and premature birth. Lead can also be transmitted through breast milk. Lead is also harmful to adults, leading to cardiovascular effects, decreased kidney function, and reproductive problems in both men and women. As with other heavy metals, treatment via reverse osmosis or ion exchange effectively reduce lead levels in water.
Here again, we see a contaminate that is widespread, has known health effects, and yet seems to catch everyone unaware when it shows up in their system. A recent article is just the tip of the iceberg. A 2013 NY Times blog discussed new evidence that levels of arsenic much lower than previously thought are responsible for chronic health effects, including respiratory problems, cardiovascular disease, diabetes, and cancers of the skin, bladder, and lungs. Arsenic interferes with the normal function of immune cells. There are no known health benefits of arsenic. Water suppliers are required to meet the standard of 10 ppb for arsenic in drinking water, but many areas don’t even require monitoring for arsenic, which is found at levels up to 500 ppb in some areas of the U.S. It is estimated that about 13 million people get drinking water from private wells with arsenic levels above the federal standard. Besides naturally occurring arsenic, shallow aquifers in land dominated by orchards may have become contaminated by past agricultural practices. Arsenic in wells is generally in either the +3 or +5 form. In more shallow aquifers with higher levels of oxygen, arsenic will usually exist as arsenate, (As+5). In deeper, anaerobic ground waters, arsenic usually occurs as arsenite, (As+3). In the pH range of 4 to 10, the predominant As (+3) compound is neutral in charge, while As (+5) species are negatively charged. This is important because the +3 is very difficult to remove from water and must be oxidized to the +5 form before it can be removed. Chlorine is the most readily available oxidant for home water treatment. Reverse Osmosis is not reliable for removing As +3 from water. Anion exchange units exchange the arsenic for chloride. These systems are generally used to treat water for the entire house and generally require little maintenance. There are other treatment options available, and you should consult with your local water treatment expert to determine the best system for your needs.
Like arsenic, uranium is widespread, and private wells generally have no testing requirements. Long-term consumption of water with elevated levels of uranium can damage kidneys and is associated with elevated risks for various cancers and both developmental and reproductive effects. The health risk is through ingestion (drinking, cooking, and brushing teeth), so activities such as bathing, handwashing, and clothes washing are not risk factors. Using water with elevated levels of uranium (or other heavy metals) on gardens with root crops or leafy greens is not recommended. Radon is a decay product of uranium. If you are in an area that requires radon mitigation and you get your water from a private well, you should test your water. If your water has tested high in uranium, you should test for radon if it’s not already mitigated due to building codes. Since you don’t need to treat all your water (only that which is used for cooking or drinking), a suitable water filter is an inexpensive work-around. Reverse osmosis is a more expensive alternative and removes a high percentage of all impurities (and minerals) from water. Like arsenic, uranium is generally found in the anionic form in water, so standard cation exchange resins are ineffective in removing it from the water.
Pesticides and Herbicides
These organic compounds, while used extensively across agricultural lands worldwide, are rarely found at levels above regulatory limits in groundwater. Exposure to these chemicals cause increased risk of cancer, liver damage, stomach problems, reproductive issues, and more. Activated carbon filters are usually effective for removing these contaminates.
My well is fouled, now what?
First, remember your water is your home’s lifeblood. Do not take actions beyond your capabilities, or you may make things worse. There are qualified well and water treatment professionals. That being said, do not be oversold. If you need to treat all your water, then you need a whole house system. If you need only to treat water for consumption, then a simple water filter or reverse osmosis system should suffice. Refer to the table below for test results from one testing lab for simple gravity water filtration systems. Finally, do not forget about your pets or livestock. They are at risk to the same pollutants as we are.
Percent reductions for selected metals for popular filters