The presence of microplastics in the Catalan rivers It has ceased to be a diffuse problem and has become a priority on the environmental agenda. These tiny fragments of plastic, which can go almost unnoticed with the naked eye, accumulate in freshwater and end up reaching wetlands, reservoirs, and ultimately the sea, with potential effects on wildlife, ecosystems, and human health.
To have one for the first time detailed x-ray To address microplastic pollution in Catalonia's waterways, the Catalan Water Agency (ACA) has launched an ambitious sampling and analysis project. This contract, already awarded and with a budget of over €291.000, will allow for the systematic study of the types of plastic particles circulating in the rivers and their impact on water quality.
A pioneering contract to measure invisible pollution
The ACA has tendered a specific contract to carry out this “microplastic census” in the most representative freshwater bodies of the territory. The planned investment exceeds 291.000 Euros and the document sets a total term of 23 monthswhich includes fieldwork, laboratory analysis, and the drawing of conclusions.
The period for submitting bids by interested companies has been set until a January 9And once the contract has been awarded and formalized, the winning company will have 14 months to carry out the sampling, followed by three months dedicated exclusively to the study of the collected samples and another three months for the obtaining and validating the resultsIn total, it took almost two years of work to obtain a solid and comparable picture of the state of the rivers.
According to the agency itself, this commission is conceived as a project pioneer in Cataloniawhich should lay the groundwork for future actions to clean up and control plastic pollution. The idea is that the information generated will not remain a mere technical report, but will serve as a guide for design concrete measures of microplastic reduction in the river environment.
The study is part of a European context in which microplastics are considered emerging pollutants And where water and waste directives are putting pressure on member states to improve the control of these particles. Although the project focuses on Catalonia, the results may be of interest to other river basins in Spain and the European Union facing similar problems.
54 checkpoints in the main river basins
The device designed by the ACA anticipates a total of 54 sampling points distributed throughout the main river basins of Catalonia. These include sections of the rivers Llobregat, Ter, Muga, Tordera, Fluvià, Besòs, Foix, Anoia and Segreas well as several streams and smaller courses, such as the Rubí and Bisbal streams, which also play a relevant role in the transport of pollutants.
The selection of these points responds to the need to obtain a representative view of the hydrographic networkThe study included areas with significant urban and industrial pressures, sections near sanitation infrastructure, and also sections located at river headwaters and areas with less human impact. This will allow for the comparison of very different situations and the detection of pollution patterns along the rivers.
In terms of distribution, the project anticipates 23 surface water samples (that is, directly in the riverbed), 26 points at the entrance and exit of wastewater treatment plants and five monitoring stations located at river headwaters. This combination will allow us to distinguish what portion of the microplastics originates from diffuse contributions (such as runoff or the erosion of urban materials) and which is associated with specific wastewater treatment infrastructures.
In total, over the three planned work campaigns, the following will be collected 123 samplesEach campaign will cover all the control points, making it easier to assess whether the presence of microplastics is stable over time or whether it varies depending on the season, episodes of heavy rain, or periods of drought.
Sources within the administration emphasize that the state of the continental water bodies It is considered especially delicate, as it is one of the ecosystems most affected by human activity. Having reliable data will allow us to know to what extent rivers act as “pollution highways"that connect urban, industrial and agricultural areas with reservoirs, wetlands and the Mediterranean coast."
What types of microplastics will be sought
One of the central objectives of the contract is to determine the quantity and type of plastic particles present in the water. The study will focus on fragments of synthetic and insoluble polymers with sizes ranging between 0,1 micrometers and 1,5 millimetersas well as in fibers with lengths ranging from approximately 0,3 micrometers up to 15 millimetersThis includes both already formed microplastics and small fibers that detach from fabrics and other materials.
The analyses will focus primarily on three very common families of plastics: the polyethylene (used extensively in bags, films and many bottles), the polypropylene (common in packaging, straws, textile components and industrial fibers) and the polystyrene (present in foams, single-use containers, kitchen utensils, and certain toys). All of these are materials that are used daily and that, once discarded, can break down into tiny particles that remain in the environment for years.
The range of sizes to be studied extends from almost microscopic fractions to small visible fragments. Detecting such small particles, on the order of tenths of a micrometer, requires specialized laboratory equipment and very careful sampling protocols, precisely to avoid cross-contamination and to be able to reliably attribute the origin of the samples.
Authorities emphasize that detecting these types of particles in rivers is “crucial"because it allows us to know if they are reaching areas where, later on, the water could be used for urban purposes, such as bottled wateragricultural or industrial. Furthermore, these plastics can be ingested by aquatic organisms, enter the food chain, and indirectly end up in the human body, an aspect that is of increasing concern to both the scientific community and European regulators.
Beyond particle counting, the contract stipulates that the analysis will also include spatial distribution of microplastics, comparing the results between upper reaches of rivers, middle reaches, and lower reaches near mouths. This information will be key to identifying where the highest levels of pollution are concentrated and what factors may be behind these differences.
The role of wastewater treatment plants and the new European requirements
A significant part of the study will focus on the role played by the wastewater treatment plants in the retention (or release) of microplastics. By including sampling at both the inlet and outlet of 26 facilities, the ACA will be able to assess how many particles the current sanitation system manages to retain and what proportion ends up returning to the rivers despite the treatments.
This line of work connects with the recent state decree on wastewater and with European guidelines, which require autonomous communities to implement more advanced sanitation systems. The medium-term goal is for a very significant proportion of wastewater treatment plants to have tertiary treatments, capable of leaving the water in an almost “prepotable"before its release into the receiving environment."
In Catalonia, the implementation of these advanced treatments is still far from widespread, although some have already taken place. first steps to strengthen the quality of treated waterThe information provided by the microplastics census will help prioritize which facilities need urgent improvements and which filtration or particle removal technologies may be most effective in each case.
Among the options being considered are systems of advanced filtrationMembrane processes, complementary physical treatments, or combinations of different techniques could be progressively incorporated into existing plants. In addition to improving the ecological status of rivers, these actions would open the door to increase the reuse of treated wastewater as an alternative resource, a particularly sensitive aspect in a context of recurring droughts.
This approach fits with the European circular economy strategy, which seeks make better use of treated wastewater and simultaneously reduce the load of emerging pollutants. If wastewater treatment plants manage to retain a greater fraction of microplastics, not only will aquatic ecosystems be protected, but the risk of these particles reaching agricultural or industrial uses will also be reduced through reuse programs.
Possible future measures and link with waste management
The Catalan government links this study with other ongoing initiatives in the field of waste and single-use plasticsThe Catalan government is working on a new waste law which, among other things, aims to reduce the generation of plastics unnecessary and promote more sustainable alternatives. The results of the microplastics census may provide additional arguments for strengthening certain obligations or reinforcing prevention systems.
If the samples detect particularly worrying concentrations In certain sections of the river or in specific geographical areas, the implementation of additional measures is not ruled out. These include increased controls on industrial waste, landfills or specific infrastructure that may be contributing high loads of plastic particles to the environment.
Detailed analysis of the data will allow us to locate possible pollution “hotspots” associated with industrial parks, dense urban areas, or specific economic activities. This will facilitate the design of tailored measures, instead of applying generic solutions that do not always adapt to the characteristics of each basin or sub-basin.
In parallel, the information obtained can be used to strengthen the citizen awareness campaigns on waste management and the responsible use of plastic products. Although the project has a strictly technical focus, the administration is aware that reducing the entry of microplastics into rivers also requires changes in the consumption and recycling habits.
For now, all these possible future actions are still on hold. to be specifiedThe intention of the Catalan Water Agency (ACA) and the Department of Territory, Housing and Ecological Transition is to wait until a solid diagnosis is available before defining new obligations or investments, so that decisions are based on verifiable data and not just general estimates.
The launch of this microplastics study places Catalonia in line with European regions that are beginning to to rigorously quantify plastic pollution in rivers and treatment plants. With 54 monitoring points, 123 samples and almost two years of planned work, the project aims to provide an accurate picture of the problem and serve as a basis for future improvements in sanitation, waste management and the protection of river ecosystems, with a focus on both environmental health and the safety of the water we use every day.
