Rubidium: Element Safety Profile
US citizens can be exposed to rubidium through rubidium 82 injections in Positron Emission Tomography (PET) scans for heart disease. Side effects of rubidium include weight gain, diarrhea, nausea or vomiting, agitation, skin rashes and others. These and other findings are outlined below.
Sources of Exposure
1) PET Scans
- The US Food and Drug Administration (FDA) flagged certain incidents in 2019 showing excess radiation exposure due to incorrect use of rubidium 82 in Positron Emission Tomography (PET) scans.
- Rubidium Rb 82 injection is used to diagnose heart disease in adults.
- The element is used as a mild radioactive dye to produce an image of the heart in PET scans.
- The FDA identified 2 PET scanner systems with user errors, namely CardioGen-82 and Ruby-Fill.
- These two systems require additive-free 0.9% sodium chloride injection USP to elute the generator.
- Investigation showed that incorrect solutions were used in several instances that allowed strontium radioisotopes to break through the rubidium injection given to patients.
- The FDA therefore required Safety Labeling Changes on labels of rubidium 82 generators to remind system users how to prepare the correct solution for the generator.
- The British Medical Bulletin also reported that rubidium-82 positron is being used in myocardial perfusion scintigraphy (MPS) PET to diagnose and manage coronary artery disease.
- Frontiers in Medicine reported in 2015 that "During the last 10 years, with the increased number of PET/CT systems and the higher strontium-82 production capabilities, the number of patients injected with rubidium-82 in the USA dramatically grew even if it still represents a small percentage by comparison with the use of 99mTc-sestamibi and 99mTc-tetrofosmin."
- The paper also adds that rubidium-82 is available daily in nuclear cardiology departments, with a generator capable of being used for 28 to 42 days.
- Rubidium oxide is used in the manufacture of glass, optics, and ceramics.
- American Elements reports that rubidium oxide is usually insoluble in water.
- It is also extremely stable which makes it ideal for use in ceramic structures such as clay bowls.
- Rubidium oxide is also found in extremely thin batteries.
- At 20°C, rubidium's conductivity is the same as sulfuric acid.
- It is also used in solid oxide fuel cells for its ionic conductivity.
- Thermofisher explains that rubidium as a metal salt produces a purple color in fireworks.
- Rubidium nitrate is a white powder highly soluble in water and slightly soluble in acetone.
- Pyrotechnic stars used in fireworks contain this color-producing chemical along with fuel, oxidizer, chlorine for enhancing color, and a binder.
- According to LennTech, plant will adsorb rubidium in case potassium is deficient.
- One example is sugar beet which, when stressed by potassium deficiency, responds by adding rubidium.
- This way rubidium joins the food chain and contributes to a daily intake of 1 mg up to 5 mg.
- The US Environmental Protection Agency (EPA) published the paper "Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds" in 2016 listing acute and subchronic effects of exposure to the element.
- Short-term effects in humans at 2.6-10.3 dosimetry (oral doses expressed as ADD or mg/kg-day) include weight gain, diarrhea, nausea or vomiting, excitement or agitation, and polyuria.
- At 5.1 and 10.3 dosimetry, short-term effects include skin rashes and diarrhea.
- At 14.3 or 21.4 dosimetry, short-term effects include change in EEG and temporary slowing of pulse.
- Sub-chronic effects in rat subjects at 0 to 2,000 dosimetry include death (dependent on dose and time), congested liver, bronchitis or bronchopneumonia and kidney congestion.
- At 167 to 500 dosimetry, subchronic side effects to rats include convulsive seizures in response to sound and light.
- At 0 to 564 dosimetry, subchronic effects to rats include death, convulsions, and reduced weight gain.
- The full table of side effects for rubidium chloride at varying levels can be reviewed here (pp. 7-12, 24).
- Drugs.com lists the following side effects of rubidium (incidence not known): "Bleeding, blistering, burning, coldness, discoloration of skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site."
- LennTech lists the following effects of overexposure to rubidium: inability to gain weight, ataxia, nervousness, skin ulcers, and hyper irritation.
- Heart conditions and potassium imbalance may also be aggravated by exposure to rubidium.