Riverine anthropogenic litter load to the Mediterranean Sea near the metropolitan area of Barcelona, Spain
Graphical abstract
Introduction
In the past decades, new technologies were based on the use of efficient and cheap alternative materials according to industrial interest. As a result, a lot of common commercial products are currently made of synthetic polymers such as plastic. A part of the plastic products is leaking from the production and use processes, e.g. by littering of single use plastics, or through waste mismanagement. The input of this litter into the environment by human activity contributes to increasing the amount of waste in coastal waters, estuaries and oceans (Vikas and Dwarakish, 2015). It represents not only an aesthetic problem but also potential damage to littoral areas, marine wildlife and the socio-economic activities linked to these regions (Rochman et al., 2016). In consequence, international organizations recognize marine litter as a severe environmental problem. In fact, several public policies have introduced different initiatives, e.g. at EU level: the Marine Strategy Framework Directive (MSFD, 2008/56/EC) (Commision, E., 2008) and the European Strategy for Plastics in a Circular Economy (COM/2018/028 final) (Commission, E, 2018a), in order to prevent and limit plastic contamination (Martin, 2013; Galgani et al., 2013; Commission, E., 2018b). However, these efforts are recent, while plastic residues are already abundant in the marine environment and have travelled long distances reaching remote areas (Cózar et al., 2017; Lavers and Bond, 2017) due to their chemical persistence and buoyancy properties. Further, plastic items in the environment are subject to fragmentation processes generating smaller pieces known as microplastics (<5 mm), which interact directly with marine organisms (Harrison et al., 2011) and may also act as vectors of emerging chemical contaminants (Bakir et al., 2014). Until recently, researchers have been mainly focused on litter already present in the marine enviroment (Ruiz-Orejón et al., 2016; Duhec et al., 2015; Martins and Sobral, 2011; Kako et al., 2018; Blettler et al., 2018), especially on the study of coastal waters adjacent to urban areas (Santos et al., 2009; Ramirez-Llodra et al., 2013). Every year between 4.8 and 12.7 million tonnes of plastic enter in the oceans (Jambeck et al., 2015). Some studies suggest that riverine litter can contribute up to 90% to all marine litter input (Öko-Institut, 2011) having an important impact on litter abundances in the marine environment (Schmidt et al., 2017; González et al., 2016) including coastal beaches (Lee et al., 2013; Veerasingam et al., 2016). Although a large share of litter entering the marine environment is assumed to come from land-based sources, these inputs have not been quantified (González-Fernández and Hanke, 2017). Rivers could transport plastic litter over long distances to downstream lakes and coastal environments, where they can interact with biota and the water ecosystem (Desforges et al., 2015; Wesch et al., 2016). The riverine transport is influenced by the morphologic and hydrologic characteristics of the catchment, which can affect the amount of waste emitted from rivers to the sea (González et al., 2016). The human population densities and urban development in the catchment area are among the factors determining the amount of mismanaged waste which could directly (or indirectly) end up in the rivers (Schmidt et al., 2017; Lebreton et al., 2017). Natural events connected to climatic and meteorological conditions (e.g. strong wind, rain or floods) play also an important role regarding the litter transport within the catchment area (Nizzetto et al., 2016; Browne et al., 2010; Yonkos et al., 2014). Therefore, the attribution of riverine litter input from mismanaged waste requires a complex previous study of the riverine area considering hotspots and possible sources, such as urban centres and wastewater treatment plants (WWTPs) (McCormick et al., 2014; Mintenig et al., 2017). In order to fill information gaps about plastic waste input from land to ocean (Jambeck et al., 2015; Schmidt et al., 2017; Lebreton et al., 2017), some initiatives have focused on riverine litter (Van der Wal et al., 2015; Surfrider Foundation Europe, 2014; Hohenblum et al., 2015). Based on needs identified within the MSFD context, the RIMMEL - Riverine and Marine floating macro litter Monitoring and Modelling of Environmental Loading - project (RIMMEL project, 2015) applied a harmonized approach for the monitoring of the litter transported from different European rivers into the marine environment. The objective of our work, within the RIMMEL project, was to estimate the riverine anthropogenic litter flux from Llobregat and Besòs River basins, which are flowing through an industrialized and populated area nearby the city of Barcelona (Catalonia, NE Spain) into the Mediterranean Sea.
Section snippets
Study areas
Two rivers were studied, the Llobregat (basin size 4948 km2) and Besòs (basin size 1024 km2) located in Catalonia (NE of Spain) (Fig. 1). The lower courses of both rivers run through the densely populated Barcelona Metropolitan area, which encompasses a population of approximately 4.4 million inhabitants. These rivers provide water supply to urban, industrial and irrigation activities, and particularly, the Llobregat river is one of the most important water resources of Catalonia. Both delta
Results and discussion
A total of 684 anthropogenic litter items were counted between October 2016 and September 2017. In particular, 297 and 387 floating items in LR and BR, respectively. Following the guidelines of the RIMMEL project, the registered items were attributed to six main categories of litter: plastic, paper, metal, rubber, textile, and wood, based on the MSFD Litter Category List (Galgani et al., 2013). Results showed similar waste composition in both rivers, mostly represented by plastic material:
Conclusions
This work provided a first monitoring study on floating macro litter items transported by rivers to the sea in two Catalan rivers, Llobregat and Besòs, influenced by the large metropolitan area of Barcelona. The analysis of most frequent anthropogenic items presented similar litter composition in both rivers. However, the difference in terms of litter loads highlighted that dimension of the catchment and the activities along the river rather influenced the amount of litter discharged. In
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors acknowledge A. Navarro Ortega, who coordinated the monitoring sessions at the beginning of the study and other 36 co-workers from the Instituto de Diagnóstico Ambiental y Estudios del Agua, Consejo Superior de Investigaciones Científicas (IDAEA-CSIC) for participating as observers in Llobregat River monitoring. Paisaje Limpio acknowledges B. Elguero and the Libera project, promoted by SEO/BirdLife in partnership with Ecoembes, for the Besòs River monitoring. Additional support was
References (77)
The plastic in microplastics: a review
Mar. Pollut. Bull.
(2017)- et al.
Transport of persistent organic pollutants by microplastics in estuarine conditions
Estuar. Coast. Shelf Sci.
(2014) - et al.
Freshwater plastic pollution: recognizing research biases and identifying knowledge gaps
Water Res.
(2018) - et al.
Macro-litter in surface waters from the Rhone River: plastic pollution and loading to the NW Mediterranean Sea
Mar. Pollut. Bull.
(2019) - et al.
Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles
Mar. Pollut. Bull.
(2015) - et al.
Microplastics in freshwater systems: a review of the emerging threats, identification of knowledge gaps and prioritisation of research needs
Water Res.
(2015) - et al.
Assessment of floating plastic debris in surface water along the Seine River
Environ. Pollut.
(2014) - et al.
Sequential webcam monitoring and modeling of marine debris abundance
Mar. Pollut. Bull.
(2018) - et al.
Macroplastic and microplastic contamination assessment of a tropical river (Saigon River, Vietnam) transversed by a developing megacity
Environ. Pollut.
(2018) - et al.
The Danube so colourful: a potpourri of plastic litter outnumbers fish larvae in Europe’s second largest river
Environ. Pollut.
(2014)
Relationships among the abundances of plastic debris in different size classes on beaches in South Korea
Mar. Pollut. Bull.
Marine debris removal: one year of effort by the Georgia Sea Turtle-Center-Marine Debris Initiative
Mar. Pollut. Bull.
Plastic marine debris on the Portuguese coastline: a matter of size?
Mar. Pollut. Bull.
Identification of microplastic in effluents of waste water treatment plants using focal plane array-based micro-Fourier-transform infrared imaging
Water Res.
Plastic in the Thames: a river runs through it
Mar. Pollut. Bull.
Effects of natural and anthropogenic processes in the distribution of marine litter in the deep Mediterranean Sea
Prog. Oceanogr.
Erosion as a possible mechanism for the decrease of size of plastic pieces floating in oceans
Mar. Pollut. Bull.
Floating plastic debris in the central and western Mediterranean Sea
Mar. Environ. Res.
On the quantity and composition of floating plastic debris entering and leaving the Tamar Estuary, Southwest England
Mar. Pollut. Bull.
Export of microplastics from land to sea. A modelling approach
Water Res.
Influence of 2015 flood on the distribution and occurrence of microplastic pellets along the Chennai coast, India
Mar. Pollut. Bull.
Coastal pollution: a review
Aquatic Procedia
Towards the suitable monitoring of ingestion of microplastics by marine biota: a review
Environ. Pollut.
Accumulation of floating microplastics behind the Three Gorges Dam
Environ. Pollut.
Balanç de les dades estadístiques de residus municipals de l'any 2017
Polymers for Packaging Applications
A hydrometeorological modeling study of a flash-flood event over Catalonia, Spain
J. Hydrometeorol.
Accumulation and fragmentation of plastic debris in global environments
Philos. Trans. R. Soc., B
Spatial patterns of plastic debris along estuarine shorelines
Environ. Sci. Technol.
Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive)
Off. J. Eur. Union
Communication From the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions a European Strategy for Plastics in a Circular Economy
Plastic Waste: A European Strategy to Protect the Planet, Defend Our Citizens and Empower Our Industries
The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the thermohaline circulation
Sci. Adv.
‘Down to the river’: amount, composition, and economic sector of litter entering the marine compartment, through the Tiber river in the Western Mediterranean Sea
Rendiconti Lincei. Scienze Fisiche e Naturali
Ingestion of microplastics by zooplankton in the Northeast Pacific Ocean
Arch. Environ. Contam. Toxicol.
98/EC of the European Parliament and of the Council, on waste and repealing certain directives
Off. J. Eur. Union
Plastic pollution in the world’s oceans: more than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea
PLoS One
Cited by (77)
Anthropogenic and environmental factors partly co-determine the level, composition and temporal variation of beach debris
2024, Journal of Hazardous MaterialsDivision and retention of floating plastic at river bifurcations
2024, Environmental PollutionSpatial accumulation of flood-driven riverside litter in two Northern Atlantic Rivers
2024, Environmental PollutionMicroplastic patterns in riverine waters and leaf litter: Leaf bag technique to investigate the microplastic accumulation trends in lotic ecosystems
2023, Journal of Contaminant HydrologyEstimating plastic pollution in rivers through harmonized monitoring strategies
2023, Marine Pollution BulletinMonitoring marine litter on Funchal beaches (Madeira Island): Insights for litter management
2023, Regional Studies in Marine Science