Together, these two characters are often thought of as nitrogen, and they’re wildly common. Even though people are starting to catch on to the fact that the over-reliance on nitrogen-rich fertilizers is causing issues ranging from dead zones in waterways and the open sea to human illness, countless farms still use millions of pounds of the stuff annually, and lots of it ends up in rivers and streams – and in groundwater, which might become your water! Be especially careful about this type of contamination if you have infants in your home.
This one we all know is bad news. Mercury poisoning can lead to organ damage after years of chronic low-level exposure, and can outright kill you if you consume a lethal dose in one go. The latter is unlikely; the former is possible for anyone who lives near a landfill, an industrial zone or in areas with lots of croplands. Water with mercury levels above .002 milligrams per liter may be dangerous so, unfortunately, a little goes a long way … toward hurting you.
If you like your kidneys, then you should hate cadmium. Sure, this element may be great for use in certain types of batteries and in certain nuclear reactors, but you still shouldn’t consume it in your drinking water if at all possible! If your plumbing has older pipes or you live in an area where groundwater may have been contaminated by certain manufacturing processes, though, maybe get the water tested from time to time.
Especially if you live near either an orchard or a factory that produces glass or electronics, the chances are that you have at least .01 milligrams of arsenic in every liter of your drinking water. That level is not high enough to cause problems in most people, but an increased level of arsenic could lead to organ failure, skin lesions and coma or death.
Even though the many health hazards this metal can cause are well understood today, lead can still be found in most all drinking water around the country. Older residences and buildings often contain plumbing made with lead (not the actual pipes, but lead is often used in solder and joint construction), while more modern construction may have low lead concentrations in fixtures made of brass or chrome. Chronic exposure to even low levels of lead can lead to a raft of health problems, especially for the very young, or those with weakened immune systems.