Why Lake Tahoe Accumulates Plastic Waste

Lake Tahoe is a popular travel destination for vacationers in the United States, and it continues to see staggering tourist numbers. Lake Tahoe sees approximately 17 million visitor days (1). As a result, anthropogenic activities are directly impacting the lake and its surrounding environment.

With Earth Day 2025 around the corner, I am revisiting an environmental analysis interview I conducted with Monica Arienzo of the Desert Research Institute back in 2023. In this brief segment, Arienzo explains how litter enters the lakebed of Lake Tahoe.

Will Wetzel: So there was a line in the abstract of the study that was published that kind of stood out to me. It mentioned that the Lake Tahoe lakebed acted as a sink for litter, and I was wondering if you could expand on the meaning of that particular statement?

Monica Arienzo: So we know that plastic litter originates on land from the human activities that are occurring there. What can happen with that litter is that, if it's not properly disposed of, it can enter lakes like Lake Tahoe from direct input. This includes people directly putting litter in the lake from a boat. It can also be blown into the lake from nearby activities, and it can enter the lake through stormwater or other rivers or streams. And this is true for all lakes. The idea is that you transport this litter into these lakes, and they can act as sinks, right? You have a slowdown in the velocity of the water if it's a river entering a lake, and those litter particles can settle and accumulate on the lakebed bottom, and they can stay there for a very long time. A lot of these are going to depend on the exact type of lake you're talking about, the residence time of that lake, and the processes that are occurring within the lake itself. In the case of Lake Tahoe, it is a pretty deep lake, and so those plastics may be sinking to the bottom of the lake, and then they might not be removed for a very long time until scuba divers go in and physically remove these plastics.

You can see the full study and my full-length video interview with Arienzo in references (2,3).

References

1. Dundas, S. Lake Tahoe Has a Staggering Tourist Problem, Report Shows. SFGATE.com. Available at: https://www.sfgate.com/renotahoe/article/lake-tahoe-tourism-report-stewardship-and-impact-18163430.php (accessed 2025-04-16).
2. Davidson, J.; Arienzo, M. M.; Harrold, Z.; West, C.; Bandala, E. R.; Easler, S.; Senft, K. Polymer Characterization of Submerged Plastic Litter from Lake Tahoe, United States. Appl. Spectrosc. 2023, ASAP. DOI: 10.1177/00037028231201174
3. Wetzel, W. Polymer Characterization of Plastic Litter Using ATR-FT-IR Spectroscopy: An Interview with Monica Arienzo. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/polymer-characterization-of-plastic-litter-using-atr-ft-ir-spectroscopy-an-interview-with-monica-arienzo (accessed 2025-04-15).