In 2019 Sequoia published a short note on our website regarding the feasibility of measuring plastic particles in situ. Two main conclusions were drawn:

1. If one considers the number concentration of plastic particles (α), and the sampling volume (SV) of any instrument used for measuring plastic particles, one can only expect to detect plastic particles when 1/ α >= SV.
2. The concentrations of plastic particles in the ocean are typically two to three orders of magnitude lower than required when the SV for LISST instruments were considered.

Despite this, there are now (June 2024) almost two dozen papers in Sequoia’s technical library describing how Sequoia’s instruments have been used to measure and/or study microplastics.

Generally, two different aspects of microplastic research that has been undertaken using LISSTs; detection methods and environmental interactions between microplastics and other particles:

1. Detection Methods: LISST-Holo2 and LISST-VSF measurements by various research groups have successfully shown that microplastics at times can be discriminated visually (using LISST-Holo2) and that its inherent optical properties have unique characteristics that may enable development of novel plastic detection techniques from above- or in-water optical measurements (LISST-VSF).
2. Environmental Interactions: Other research using predominantly the LISST-200X or LISST-100X has focused on how microplastics can interact with oil droplets, plankton, dissolved organic matter, nanobubbles, turbulence or sediment particles. Subsequently how these interactions affect the entrainment, mobilization, transport, sedimentation and retention of microplastics in the environment: On shorelines, coastal water bodies, in the offshore regions, in landfill leachate, drainage systems, and wetlands as illustrated in the figure.

ChatGPT generated image showing the environments and landscape elements where LISST instruments have been used for microplastic research in situ

Reflecting the pervasive nature of microplastics, these studies contribute to the growing body of microplastics knowledge and their potential impacts on the environment. The references are all available from Sequoia’s technical library.