Cadmium in Drinking Water
For many families, the safety of their home’s tap water is something taken for granted, until a concern about heavy metal contamination arises. While we often hear about lead or arsenic, cadmium is another toxic heavy metal that can quietly compromise drinking water quality.
Understanding how cadmium enters your water supply and how to effectively remove it is essential for protecting your family’s long-term health.
Cadmium in Drinking Water at a Glance:
Health Effects: Gastrointestinal issues, liver damage, kidney damage, and blood damage.
MCL: 5 ppb
Test: Safe Home Metals Test Kit
Treatment: Carbon Filters at Point of Use (POU)
What is Cadmium?
Cadmium is a naturally occurring, soft, bluish-white metal. It is rarely found as a pure element in nature; instead, it is usually extracted as a byproduct of mining or refining other metals like zinc, lead, and copper.
Because of its chemical properties, cadmium has historically been used in a wide range of industrial applications, including:
- Batteries: Specifically nickel-cadmium (NiCd) rechargeable batteries.
- Coatings: Applied to metals to prevent corrosion and rust.
- Stabilizers: Used in certain PVC plastics.
How Does Cadmium Enter Drinking Water?
Cadmium typically enters residential water systems through three primary pathways:
Corrosion of Plumbing
In older homes, galvanized iron pipes (pipes coated with zinc) were common. If the zinc coating contains impurities, cadmium can leach into the water as the pipes corrode over time. This is especially prevalent in homes acidic or aggressive water.
Industrial and Agricultural Runoff
Cadmium is released into the environment through wastewater from metal refineries, mining operations, and battery manufacturing facilities. It can also enter groundwater through the disposal of cadmium-containing hazardous waste in landfills.
Erosion of Natural Deposits
Cadmium exists naturally in the earth’s crust. In some regions, groundwater passing through mineral deposits can naturally pick up trace amounts of the metal.
Negative Effects of Cadmium in drinking water
The Environmental Protection Agency (EPA) states that Cadmium can cause kidney damage if it is consumed at high levels. Because the body processes cadmium very slowly, it can accumulate in the kidneys and liver over many years.
- Short-Term Exposure: Consuming water with high levels of cadmium can cause immediate gastrointestinal distress, including nausea, vomiting, abdominal cramps, and diarrhea.
- Long-Term Exposure: Chronic ingestion, even at lower levels, is primarily associated with kidney damage. Over time, it can also lead to bone demineralization (making bones brittle and prone to fractures) and potential liver toxicity.
What level of Cadmium in drinking water is dangerous?
To protect public health, the EPA has set a Maximum Contaminant Level (MCL) for cadmium in public water systems at 0.005 mg/L (or 5 parts per billion).
If you are on tap water, then your city water system will monitor for Cadmium. But this only monitors the water at the utility. It doesn’t measure if your drinking water is leeching Cadmium or other heavy metals between the utility and your faucet.
If you are on private well water, you are solely responsible for testing your drinking water.
How to Test for Cadmium in Drinking Water
To test for Cadmium, we recommend the Safe Home Heavy Metals Test Kit. This test kit will let you collect your sample at home and then have it analyzed at our EPA certified laboratory.
What to do if your Cadmium Levels are too High
If testing reveals cadmium levels exceeding the EPA limit, several proven filtration technologies can remove it effectively.
Reverse Osmosis (RO)
An RO Filter is one of the most popular filtration option and can be installed only at the point-of-use (like the kitchen sink) to save money. When paired with a carbon pre-filter, RO systems are highly effective at removing heavy metals.
Distillation
Distillation units boil water into steam and then condense it back into a liquid in a clean container. This process leaves behind virtually all minerals and heavy metals, including cadmium, though it is a slower process compared to filtration.
Other Options to remove Cadmium
There are other effective options to remove Cadmium such as Ion-Exchange. It’s important to talk to a filtration profession about your exact needs. If you’ve had laboratory water testing, your filtration professional can look at the lab report and give you recommendations based on your unique situation.