Experts Identify Looming Environmental Impacts of Batteries Within Diabetes Devices

The number of discarded continuous glucose monitoring (CGM) devices amounts to more than 196 million units per year. Although this clinical technology revolutionizes diabetes care, it is not without concerns. Each stage of the CGM battery lifecycle contains the potential for detrimental environmental impact. The Journal of Diabetes and Science Technology published an analysis using data from the International Energy Agency (IEA) discussing how device production, resource consumption, and device disposal can contribute to CGMs carbon footprint.

A woman with a glucose monitor on her arm | Image credit: Andrey Popov | stock.adobe.com

Manufacturers are starting to make strides in the production design of CGMs. For example, Abbott has shrunk their Freestyle Libre 3 sensor roughly 70% in size, resulting in 41% less plastic than earlier generations. Beyond product design (and often ignored) is the environmental impact of the battery powering these devices.

The 2 popular battery systems used by manufacturers of CGMs are zinc-silver oxide system (used within Freestyle Libre sensors and Omnipod pumps) and lithium metal-manganese dioxide system (used within Dexcom sensors). The mining processes for lithium and silver both have significant environmental drawbacks.

Lithium mining requires 1900 tons of water per ton of lithium extracted, depleting water levels by 65% in surrounding areas. Meanwhile, silver extraction uses corrosive metals (i.e. cyanides, ferricyanides) that can contaminate the water and soil. One such accidental spill contaminated drinking waters in Hungary, Romania, and Yugoslavia and resulted in the deaths of 150 tons of fish.

The disposal of batteries contained within CGMs can potentially further complicate the adverse environmental consequences. When incinerated, the zinc-silver dioxide batteries may release harmful gasses that can cause health risks. Additionally, when the battery is left solid in a landfill, heavy metals such as silver pose the risk of contaminating groundwater. Furthermore, lithium-manganese dioxide batteries react violently with air and water, making them highly flammable and a significant fire hazard if left untreated.

So, how can pharmacists help the environment amid growing public interest in these helpful tools?

Firstly, pharmacists can be on the lookout for sensor kit take-back and pod take-back programs and encourage patients to take notice. Collected supplies will be sent to specialized waste-to-energy facilities and avoid landfills. For example, the Abbott Freestyle website provides more information on their program.

Additionally, consider devices with rechargeable batteries instead of single-use primary batteries. For example, the Medtronic Guardian transmitters require once-weekly charging but possess a battery capable of lasting an entire year.

For patients with multiple daily insulin injections, recommend one of the reusable smart insulin pen devices. For instance, the NovoPen (Novo Nordisk) utilizes a lithium battery that lasts 4 to 5 years.

CGM technology has changed the game for diabetes treatment, but it is not without limitations. In order to continue the progress of diabetes self-management, issues with the current resources and associated environmental risk factors must be addressed.

REFERENCE

Avari P, Cai Y, Verma V, Reddy M, Srinivasan M, Oliver N. Batteries Within Diabetes Devices: A Narrative Review on Recycling, Environmental, and Sustainability Perspective. J Diabetes Sci Technol. Published online September 10, 2024. doi:10.1177/19322968241278374