Combined Radium (226 + 228)
Overview
Radium is a naturally occurring radioactive element that erodes from underground rock into groundwater. It is measured as the combined activity of radium-226 and radium-228.
In Florida, Combined Radium (226 + 228) was found in 10 community water systems serving about 843,006 people. It was measured by 1,559 systems in all, so it was detected in under 1% of the systems that tested for it.
The highest reading relative to the limit was at City of Arcadia in DeSoto County, at 91% of it.
Where it comes from: Erosion of natural deposits.
The standards
Enforceable. A utility must stay at or under this.
Health-based, not enforceable. Often lower than the limit, sometimes zero.
California OEHHA PHG for Radium-226 (2006).
Health effects the EPA associates with it: May increase the risk of cancer.
The health goal is set on health alone. The legal limit is set as close to it as is technically and economically feasible, so treatment cost and available technology are written into the number a utility is measured against. A system at or under the limit is meeting the standard it is required to meet. Both numbers are shown so the distance between them is visible.
What removes it
A standard water softener removes radium, which behaves like calcium and is captured by ion exchange. Reverse osmosis works too. Carbon does not. The softener carries the radium out in its backwash, which is how the system is meant to work.
Treatment guidance describes the methods generally used for this contaminant. What your own tap actually carries depends on your plumbing and your service line as much as on the utility, which is what a test at the house tells you and an annual report cannot.
Where in Florida
Highest reported levels
Data Sources
These figures describe water as delivered by each utility, not what your home’s plumbing adds after it arrives. Informational; not a substitute for testing your own tap.