Handheld portable FTIR spectroscopy for the triage of micro and meso sized plastics in the marine environment incorporating an accelerated weathering study and an aging estimation

Debris in the marine environment can be either natural, such as floating vegetation or volcanic ash deposits, or man-made. The man-made human sources cover the whole gamut of material types, from sewage, glass, mineral, fabric and, of increasing concern, plastic or polymeric. Virtually all plastics absorb IR in a highly selective manner, making their IR spectra a useful qualitative diagnostic. The triage of the visible micro (~1mm-5mm), meso, macro or mega particles with portable and handheld FTIR enables rapid determination of the material on-site, and reduces time wasted on non-polymers on-site or at site. Four most prevalent commodity neustonic plastic types, and their FTIR spectral changes correlated with accelerated weathering, were successfully examined chronologically, detailing significant differences in aging profiles and chemical changes. Subsequently, a small spectroscopically identifiable degraded piece of plastic found in Greenland was correlated to the appropriate aging profile. Finally, a targeted methodology for quantification of sub-millimeter microplastic in dried estuarine sediment was evaluated to ascertain its potential limit of detection.