The contamination of natural aquatic ecosystems with plastic particles, particularly in the range of millimeters, micrometers and nanometers, turns out to be a more and more ubiquitous problem. Its extent and the resulting consequences for man and nature are not yet foreseeable. First findings suggest that both open sea and littoral waters as well as inland waters such as rivers and lakes are affected by the pollution. Not only the physical presence of the plastic particles in the environment and their possible accumulation are presumed to be potentially problematic. Their tendency to adsorb and resorb organic pollutants (e.g. PAH and PCB, chlorinated pesticides, softeners) on their surface – leading to a possible bioaccumulation of pollutants in the food chain – cause increasing concern.
Public authorities and industries are therefore more and more in charge to advance the monitoring of natural and artificial waters – including urban and industrial wastewater, as these are potential entry routes for the plastic particles into the environment. A holistic recording of the level of pollution as well as the implementation of respective avoidance and reduction strategies will soon be indispensable. Notably with regard to the implementation of the EU Marine Strategy Framework Directive (MSFD) and the EU Water Framework Directive, there is a great need for efficient and standardized monitoring procedures allowing a reliable and consistent application on a local, regional and international level.
Despite the first promising approaches, thanks to sporadic cooperations between research institutions and companies, no tool box with suchlike procedures for holistic remote observation, sample drawing analysis and (online) evaluation of plastic particles and associated pollutants in different water systems exists so far.
The purpose of the PlaMoWa network is the targeted development of integrated, parly automated (in situ) procedures for a systematic, holistic and standardized
- Environmental observation: Remote observation of the transport and entry of plastics via optical sensors
- Sample drawing: Drawing, filtration and isolation of plastic particles
- Particle analysis: Identification, characterisation and quantification of the isolated plastic particles
- Pollutant analysis: Identification, characterisation and quantification of organic compounds associated to the isolated plastic particles and stemming from the water column, sediments and different biota in natural watercourse and standing water body as well as the coastal waters, urban and industrial sewage systems; including
- Data integration: Conjunction and combined (online) evaluation as well as documentation and archiving of the part data sets respectively meta data sets, considering various internal and external (environmental) parameters.
The examination of the water column, sediments and biota in search of plastic particles with a size in the range of millimeters, micrometers and nanometers requires fundamentally different strategies on remote observation, sample drawing, analytics and analysis. The physico-chemical characteristics as well as the organic concentration of the different water types (saltwater, softwater, brackish water, wastewater) also play a considerable role. These factors shall be significantly taken into account by aligning the lines of development to the different sample types in the respective environment. As a result, a tool box allows a combined or sole application of various, partly concerted procedures.
In a first approach, the following lines of development have been identified:
- Environmental observation: Automatic identification and quantification of plastics via sensor system and algorithms for real-time analysis, e.g. in situ video cameras, imaging spectometers and satellite sensors
- Sample drawing: Horizontal and vertical sample drawing using combined net prodecures, or in situ pumping and filtration methods, if applicable in combination with spectroscopic examination
- Particle analysis: Combined, partly automated sample preparation including sieving, filtration and/ or fluid flow fractionation as well as enzyme fermentation; identification and quantification with Raman micro-spectroscopy, FT-IR spectroscopy oder imaging VNIR-SWIR spektroscopy
- Pollutant analysis: Thermo desorption coupled with gas chromatography and mass spectroscopy with regulated temperature programm and direct injection of the plastic particles via an automatic liner changing system
- Data integration: User-friendly software programm with different modules for sole and combined data analysis and archiving
The aspired development of integrated, partly automated (in situ) procedures shall not only meet the increasing demand of holistic and standardized methods for national and international monitoring of waters. It shall also foster the initiation of further development projects mapping out long-term strategies to avoid or reduce aquatic plastic pollution. These strategies can address e.g. changes in industrial processes of plastic production and recycling or measures for wastewater treatment and water body restauration. Therefore, we aim to also prepare a first draft of realistic, environmentally sound approaches to reduce the existing plastic pollution without disturbing the biological and chemical equilibrium in the ecosystem.