29 D2. Hydrology and Water Quality in the Southeast U.S. (Posters)

Friday, 21 March 2025
8:00 AM - 12:00 PM
Shenandoah ABC

REFLECTIVE SPECTROSCOPY OF MACROPLASTICS FROM A BEACH ENVIRONMENT AT CABO ROJO, SOUTHWESTERN PUERTO RICO.

Paper number: 29-12
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

Both macroplastics and microplastics are widely recognized problems in marine environments globally. The volume of plastics in marine ecosystems is a growing number and issue. The plastics cause great harm to marine organisms through entanglement and ingestion. In addition, plastics may release harmful chemicals and toxins into the water through leaching. Identifying and monitoring the scope of the plastic pollution crisis is problematic as the scale of pollution is so large. Hyperspectral remote sensing / image spectroscopy (HRS/IS) is one method that can capture and potentially identify macroplastics in large scenes from air or spaceborne platforms. Plastic pollution in Puerto Rico is comparatively understudied in the context of HRS/IS. To effectively improve this capacity, detailed materials libraries need to be assembled based on materials retrieved in the environment. In January 2024, a collection of macroplastics as well as sediment was collected from a major beach associated with Cabo Rojo, SW Puerto Rico. An ASD Fieldspec 4 spectroradiometer was used to measure a collection of macroplastics and sediment. Grain size analysis of sediment varies from 0.180 to 16.00 mm and powder X-ray diffraction characterized sediment as calcite and aragonite-rich. Reflective spectroscopy data indicates that there are distinct plastic populations with absorption features that readily distinguish macroplastics from sediment. Major absorption features observed amongst plastics are at approximately 1140 nm, 1410 nm, 1675 nm, 1750 nm, 1900 nm, 2065 nm, 2135 nm, 2165 nm, 2190 nm, 2300 nm, 2350 nm, and 2450 nm. Ultraviolet exposure may cause some variation in spectral properties of plastics owing to degradation. This investigation provides new data for HSR/IS investigations of coastal environments of Puerto Rico and broadly supports plastic pollution investigations globally in carbonate sand environments.

Geological Society of America Abstracts with Programs. Vol. 57, No. 2

doi: 10.1130/abs/2025SE-407462

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