My Research Journey

• NOAA EPP Earth System Sciences and Remote Sensing Scholar at San Diego State University

• Degree: M.S. Geography Candidate with concentration in Watershed Science

• Research Area: Remote Sensing Macroplastics in Coastal Watersheds

• Advisors: Dr. Trent Biggs & Dr. Amy Quandt

• NOAA Mentor: Dr. Amy Uhrin, Marine Debris Program (MDP)

Title

Laboratory reflectance spectra of plastic waste in a coastal binational watershed: Viability of mapping at scale with hyperspectral and multispectral remote sensing  

Project Description

Mismanaged plastic waste (MPW) in rivers, streams, and marine environments disrupt ecosystems, human health, and economies (van Emmerik & Schwarz, 2020). It is estimated that 1-2 million tons of plastic waste enter the world’s oceans via rivers and flooding plays a role in increased plastic mobilization (Lebreton, 2017; Roebroek, C. T. J., 2021). In the United States (US), marine debris flows are a major challenge for managing coastal waters. On the US-Mexico border, several transboundary watersheds originate in Mexico and discharge water, sediment, and debris into the US. One coastal transboundary watershed, Los Laureles Canyon Watershed (LLCW) part of the Tijuana River Watershed (TRW), originates in Tijuana and crosses the border into the Tijuana Estuary (TE) in Imperial Beach, San Diego. 

Using a combination of field assessments and remote sensing methods, I aim to advance macroplastic identification in this region by:

1. determining plastic pollution hotspots in LLCW ephemeral stream channels,
2. collecting samples of disposed plastic debris from each hotspot location and the Tijuana Estuary trash boom,
3. processing materials in the reflectance spectroscopy laboratory at SDSU
4. characterize the diversity of plastic reflectance found in LLCW and TE using the resulting spectral library,
5. and identify the separability of materials for different types of commonly-available satellite imagery and broadband multispectral bands.

Social Relevance

Results from this research can support a number of spatial and temporal analyses on macroplastic disposal, accumulation, distribution and transport in a watershed. I will use the results of this study to validate field assessments and long-term hotspot locations. If spectral signatures associated with MPW can be uniquely identified, they will be used to map materials in airborne and satellite imagery across the study area and throughout several time periods. It is hypothesized that some trash services do not reach households living near or within the hotspot locations due to the lack of road infrastructure needed for collection trucks to recover household-generated solid waste. If this is true, MPW challenges in this watershed may be associated more with a lack of resources than a need for behavior change interventions. 

Observing the highly dynamic nature of this issue using remotely sensed data may uncover social and biophysical patterns and drivers associated with MPW. Locating the absorption features of plastics and preparing a spectral library can also assist in the creation of a hyperspectral sensor that could be used for long-term monitoring and debris detection at larger spatial scales.

Acknowledgement 

This study is supported and monitored by The National Oceanic and Atmospheric Administration – Cooperative Science Center for Earth System Sciences and Remote Sensing Technologies under the Cooperative Agreement Grant #: NA16SEC4810008. The authors would like to thank the NOAA Educational Partnership Program with Minority Serving Institutions for fellowship support for Elena Aguilar and the Center for Earth System Sciences and Remote Sensing Technologies. The statements contained within the Story Map are not the opinions of the funding agency or the U.S. government, but reflect the author’s opinions. 

References

Lebreton, L. C. M., van der Zwet, J., Damsteeg, J. W., Slat, B., Andrady, A., & Reisser, J. (2017). River plastic emissions to the world’s oceans. Nature Communications, 8. https://doi.org/10.1038/ncomms15611

Roebroek, C. T. J., Harrigan, S., van Emmerik, T. H. M., Baugh, C., Eilander, D., Prudhomme, C., & Pappenberger, F. (2021). Plastic in global rivers: Are floods making it worse? Environmental Research Letters, 16(2). https://doi.org/10.1088/1748-9326/abd5df

van Emmerik, T., & Schwarz, A. (2020). Plastic debris in rivers. Wiley Interdisciplinary Reviews: Water, 7(1), e1398. https://doi.org/10.1002/wat2.1398.