A Peristaltic Pump and Filter-Based Method for Aqueous Microplastic Sampling and Analysis

Sampling the aquatic environment for microplastic concentration is
inherently difficult because of variations in microplastic concentration,
shape, and density and the potential for contamination. We present an
assessment of a method for microplastic sampling that uses a peristaltic
pump to pump water through a series of in-line stainless-steel mesh
filters. Following filtration, the stainless-steel filters were treated
using previously published methods to isolate microplastics, adjusted for
the stainless-steel mesh filters. Microplastics were identified using
micro-Fourier Transform Infrared (µFTIR) spectroscopy in transmission
mode. This method was tested in the laboratory using standard polyethylene
beads and was applied to two sample sites at the Las Vegas Wash in Nevada.
The results showed 70% of the polyethylene beads were recovered after the
peristaltic pump and laboratory steps with minimal blank contamination.
The advantages of the peristaltic pump sampling method are it (1) supports
a range of sample volumes, (2) reduces sample handling, (3) reduces the
potential for contamination, (4) provides flexibility in sampling
locations, and (5) supports a variety of filter types. Using
stainless-steel mesh filters allows for (1) streamlined and direct
field-to-laboratory sample processing, (2) µFTIR transmission mode
analysis of filter-mounted microplastics, and (3) reduced filter and
sample processing costs.