Since the middle of last century global production of plastics was accompanied by an accumulation of plastic litter in the marine environment. Being dispersed by currents and wind, persistent plastics are mostly not degraded but fragmented leading to an increasing amount of small plastic particles, so called “micro-plastics”, in the marine environment. Due to their small size, micro-plastics have the potential of being ingested by benthic and planktonic organisms and thus of entering marine food webs. For reliable evaluation and assessment of food web effects, a detailed quantitative and qualitative monitoring of micro-plastics in the marine environment is highly required and thus stipulated within the framework of the Marine Strategy Framework Directive (MSFD). Due to the methodology currently used, the scarce data on micro-plastics concentrations is mostly biased towards larger particles. Therefore, reliable data on concentrations of micro-plastics in marine systems are still lacking but of utmost importance.

Fourier Transform infrared (FT-IR) spectroscopy offers the possibility of proper identification of plastic particles in environmental samples. However, standard FT-IR still requires time- and labour-consuming pre-sorting of particles by hand. Hence, small or less abundant micro-plastics are potentially overlooked. A highly promising FT-IR extension (FT-IR Imaging) allows for detailed and unbiased high throughput analysis of total micro-plastics in a given sample without prior pre-sorting by hand.

Within the framework of the project MICROPLAST, the AWI aims to develop and apply a standardised high throughput analysis procedure based on FT-IR Imaging for the analysis of micro-plastics in different sample types from different marine regions (as defined by the MSFD). Appropriate methods for the extraction of micro-plastics in complex matrices, such as plankton- or sediment-samples, will be developed and adjusted for FT-IR Imaging. After establishment of appropriate SOPs, the FT-IR Imaging system can also serve as a platform for intercalibration and quality assurance for micro-plastic detection within the project.

• MICROPLAST is a BMBF project