Physics

Geology

Mathematics

Particle-size distribution

Biology

Fourier transform

Environmental chemistry

Analytical Chemistry (journal)

Optics

Oceanography

Mathematical analysis

Cardinal point

Physical chemistry

Particle size

Composite material

Fourier transform infrared spectroscopy

Mass spectrometry

Chemistry

Ecology

Materials science

Range (aeronautics)

Particle (ecology)

Wastewater

Environmental science

Chromatography

Pollution

Environmental engineering

Water Research

This paper presents a method for microplastic (MP) mass quantification using a Focal Plane Array-based Fourier Transform Infrared imaging technique. It discusses the issue that particle number is not a conserved base quantity and hence less suited than mass to compare independent studies on MP in the environment. It concludes that MP mass should be included when quantifying MP pollution in the environment, supplementing the conventional approach of reporting particle numbers. Applying mass as the unit of MP measurement, the paper presents data showing that Danish wastewater treatment plants discharge around 3 t/year of MP in the size range 10–500 μm. This value corresponds to an annual per capita emission from these plants of 0.56 g MP/(capita year). The distribution of polymer types by mass and particle number differed because the size of MP particles of the different material types varied.

Quantification of microplastic mass and removal rates at wastewater treatment plants applying Focal Plane Array (FPA)-based Fourier Transform Infrared (FT-IR) imaging