<p>Information on the transport and deposition of riverine macroplastic is crucial ... more <p>Information on the transport and deposition of riverine macroplastic is crucial for selecting proper locations for river cleaning actions and for trapping infrastructure installation. Obtaining such information for mountain rivers is of particular importance because their specific characteristics make them particularly prone to illegal dumping, plastic litter input from slope to the river channel, and an increased rate of secondary microplastic production in the river channel (<strong>1</strong>).</p> <p>To shed some light on the patterns of macroplastic transport and deposition along mountain rivers we have performed a field experiment utilizing tracked plastic (PET) bottles injected to the channel of the mountainous Skawa River in the Polish Carpathians. After 50-57 days of low-flow conditions, we documented transport distances (<em>n</em>=64) which were non-normally distributed and reached from 0.37 km to 16.27 km (median=1.73 km, quartile range=5.29 km). Most of the tracked bottles were deposited on woody debris (71.9%,<em> n</em>=46) (Photo 1) at elevations ranging from 0 to 1.2 m (median=0.4 m, quartile range=0.45 m) above the low-flow water level. Surprisingly, the straight and narrow channelized reach of the studied river trapped 15.3 % of the plastic bottles transported through it, while the highly sinuous, wide unregulated one only 8.7 %, which is probably related to the more frequent contact of woody debris (present in both reaches) with the flowing water, occurring during low-flow conditions within the narrower, channelized reach.</p> <p>Our initial results suggest that places of woody debris deposition along rivers can be a good location for river cleaning actions. </p> <p><img src="" alt="" /></p> <p><strong>Photo 1</strong>. The deposition of plastic bottles on wood jam<br />(the Skawa River, S Poland) (photo by M. Liro)</p> <p> </p> <p>References</p> <p><strong>(1) </strong>Liro, M., van Emmerik, T.H., Zielonka, A., Gallitelli, L., Mihai, F.C., 2023. The unknown fate of macroplastic in mountain river. <em><strong>Sci. Total Environ</strong></em>. <em>865, 161224.</em></p>
Plastic waste poses numerous risks to mountain river ecosystems due to their high biodiversity an... more Plastic waste poses numerous risks to mountain river ecosystems due to their high biodiversity and specific physical characteristics. Here, we provide a baseline assessment for future evaluation of such risks in the Carpathians, one of the most biodiverse mountain ranges in East-Central Europe. We used high-resolution river network and mismanaged plastic waste (MPW) databases to map MPW along the 175,675 km of watercourses draining this ecoregion. We explored MPW levels as a function of altitude, stream order, river basin, country, and type of nature conservation in a given area. The Carpathian watercourses below 750 m a.s.l. (142,282 km, 81 % of the stream lengths) are identified as significantly affected by MPW. Most MPW hotspots (>409.7 t/yr/km2) occur along rivers in Romania (6568 km; 56.6 % of all hotspot lengths), Hungary (2679 km; 23.1 %), and Ukraine (1914 km; 16.5 %). The majority of the river sections flowing through the areas with negligible MPW (< 1 t/yr/km2) occur in Romania (31,855 km; 47.8 %), Slovakia (14,577 km; 21.9 %), and Ukraine (7492; 11.2 %). The Carpathian watercourses flowing through the areas protected at national level (3988 km; 2.3 % of all watercourses studied) have significantly higher MPW values (median = 7.7 t/yr/km2) than those protected at regional (51,800 km; 29.5 %) (median MPW = 1.25 t/yrkm2) and international levels (66 km; 0.04 %) (median MPW = 0 t/yr/km2). Rivers within the Black Sea basin (88.3 % of all studied watercourses) have significantly higher MPW (median = 5.1 t/yr/km2, 90th percentile = 381.1 t/yr/km2) than those within the Baltic Sea basin (median = 6.5 t/yr/km2, 90th percentile = 84.8 t/yr/km2) (11.1 % of all studied watercourses). Our study indicates the locations and extent of riverine MPW hotspots in the Carpathian Ecoregion, which can support future collaborations between scientists, engineers, governments, and citizens to better manage plastic pollution in this region.
Mountain rivers are typically seen as relatively pristine ecosystems, supporting numerous goods (... more Mountain rivers are typically seen as relatively pristine ecosystems, supporting numerous goods (e.g., water resources) for human populations living not only in the mountain regions but also downstream from them. Recent evidence suggests, however, that mountain river valleys in populated areas can be substantially polluted by macroplastic (plastic item > 5 mm). It is, however, unknown how distinct characteristics of mountain rivers modulate macroplastic routes through them, which makes planning effective mitigation strategies difficult. To stimulate future works on this gap, here, we present a conceptual model of macroplastic transport pathways through mountain river. Based on this model, we formulate four hypotheses on macroplastic input, transport and degradation in mountain rivers. Then, we propose designs of field experiments that allow each hypothesis to be tested. We hypothesize that some natural characteristics of mountain river catchments (e.g., steep valley slopes, mass ...
Macroplastic pollution in mountain rivers can threaten water resources, biodiversity, and the rec... more Macroplastic pollution in mountain rivers can threaten water resources, biodiversity, and the recreational values provided by them. The first step towards evaluating and then mitigating these risks is the systematic collection of reliable and spatially uniform data on the amount and type of macroplastics deposited in different land covers occurring in a mountain river channel. To maximise the opportunity for the large-scale collection of such data using the citizen science approach, we propose in this study an illustrated step-by-step guide to sample the macroplastic deposited along mountain rivers and to record the collected information using a photo taken by smartphone and a simple online form. Our guide includes three steps: (i) the location of sampling plots across 3–4 predefined surface covers occurring in mountain rivers of temperate climate, (ii) the hand collection of macroplastic deposited in them, and (iii) the photorecording and archiving of information on macroplastics c...
The water depth and flow velocity of a river may be temporarily disturbed by the water level fluc... more The water depth and flow velocity of a river may be temporarily disturbed by the water level fluctuations connected with the operation of artificial dam reservoirs located downstream (so-called backwater fluctuations (BF)). In this research, we use the two-dimensional hydrodynamic model iRIC MFlow_02 to quantify the effects of BF on the lowermost section (ca. 1.5-km length) of a small (channel width ≤ 20 m) mountain stream, the Smolnik Stream, which flows into the Rożnów Dam Reservoir, in Southern Poland. To reproduce the hydrological conditions generally observed in the stream, six scenarios were simulated, considering three steady flow discharges at the inlet, with recurrence intervals of 1 year (1.8 m3 s−1, small flood), 2 years (24.5 m3 s−1; medium flood), and 20 years (89.5 m3 s−1; large flood), and two reservoir levels at the outlet: 265 m a.s.l. (normal reservoir water level) and 270 m a.s.l. (maximum reservoir water level). In these simulations, sediment transport and morpho...
<p>Information on the transport and deposition of riverine macroplastic is crucial ... more <p>Information on the transport and deposition of riverine macroplastic is crucial for selecting proper locations for river cleaning actions and for trapping infrastructure installation. Obtaining such information for mountain rivers is of particular importance because their specific characteristics make them particularly prone to illegal dumping, plastic litter input from slope to the river channel, and an increased rate of secondary microplastic production in the river channel (<strong>1</strong>).</p> <p>To shed some light on the patterns of macroplastic transport and deposition along mountain rivers we have performed a field experiment utilizing tracked plastic (PET) bottles injected to the channel of the mountainous Skawa River in the Polish Carpathians. After 50-57 days of low-flow conditions, we documented transport distances (<em>n</em>=64) which were non-normally distributed and reached from 0.37 km to 16.27 km (median=1.73 km, quartile range=5.29 km). Most of the tracked bottles were deposited on woody debris (71.9%,<em> n</em>=46) (Photo 1) at elevations ranging from 0 to 1.2 m (median=0.4 m, quartile range=0.45 m) above the low-flow water level. Surprisingly, the straight and narrow channelized reach of the studied river trapped 15.3 % of the plastic bottles transported through it, while the highly sinuous, wide unregulated one only 8.7 %, which is probably related to the more frequent contact of woody debris (present in both reaches) with the flowing water, occurring during low-flow conditions within the narrower, channelized reach.</p> <p>Our initial results suggest that places of woody debris deposition along rivers can be a good location for river cleaning actions. </p> <p><img src="" alt="" /></p> <p><strong>Photo 1</strong>. The deposition of plastic bottles on wood jam<br />(the Skawa River, S Poland) (photo by M. Liro)</p> <p> </p> <p>References</p> <p><strong>(1) </strong>Liro, M., van Emmerik, T.H., Zielonka, A., Gallitelli, L., Mihai, F.C., 2023. The unknown fate of macroplastic in mountain river. <em><strong>Sci. Total Environ</strong></em>. <em>865, 161224.</em></p>
Plastic waste poses numerous risks to mountain river ecosystems due to their high biodiversity an... more Plastic waste poses numerous risks to mountain river ecosystems due to their high biodiversity and specific physical characteristics. Here, we provide a baseline assessment for future evaluation of such risks in the Carpathians, one of the most biodiverse mountain ranges in East-Central Europe. We used high-resolution river network and mismanaged plastic waste (MPW) databases to map MPW along the 175,675 km of watercourses draining this ecoregion. We explored MPW levels as a function of altitude, stream order, river basin, country, and type of nature conservation in a given area. The Carpathian watercourses below 750 m a.s.l. (142,282 km, 81 % of the stream lengths) are identified as significantly affected by MPW. Most MPW hotspots (>409.7 t/yr/km2) occur along rivers in Romania (6568 km; 56.6 % of all hotspot lengths), Hungary (2679 km; 23.1 %), and Ukraine (1914 km; 16.5 %). The majority of the river sections flowing through the areas with negligible MPW (< 1 t/yr/km2) occur in Romania (31,855 km; 47.8 %), Slovakia (14,577 km; 21.9 %), and Ukraine (7492; 11.2 %). The Carpathian watercourses flowing through the areas protected at national level (3988 km; 2.3 % of all watercourses studied) have significantly higher MPW values (median = 7.7 t/yr/km2) than those protected at regional (51,800 km; 29.5 %) (median MPW = 1.25 t/yrkm2) and international levels (66 km; 0.04 %) (median MPW = 0 t/yr/km2). Rivers within the Black Sea basin (88.3 % of all studied watercourses) have significantly higher MPW (median = 5.1 t/yr/km2, 90th percentile = 381.1 t/yr/km2) than those within the Baltic Sea basin (median = 6.5 t/yr/km2, 90th percentile = 84.8 t/yr/km2) (11.1 % of all studied watercourses). Our study indicates the locations and extent of riverine MPW hotspots in the Carpathian Ecoregion, which can support future collaborations between scientists, engineers, governments, and citizens to better manage plastic pollution in this region.
Mountain rivers are typically seen as relatively pristine ecosystems, supporting numerous goods (... more Mountain rivers are typically seen as relatively pristine ecosystems, supporting numerous goods (e.g., water resources) for human populations living not only in the mountain regions but also downstream from them. Recent evidence suggests, however, that mountain river valleys in populated areas can be substantially polluted by macroplastic (plastic item > 5 mm). It is, however, unknown how distinct characteristics of mountain rivers modulate macroplastic routes through them, which makes planning effective mitigation strategies difficult. To stimulate future works on this gap, here, we present a conceptual model of macroplastic transport pathways through mountain river. Based on this model, we formulate four hypotheses on macroplastic input, transport and degradation in mountain rivers. Then, we propose designs of field experiments that allow each hypothesis to be tested. We hypothesize that some natural characteristics of mountain river catchments (e.g., steep valley slopes, mass ...
Macroplastic pollution in mountain rivers can threaten water resources, biodiversity, and the rec... more Macroplastic pollution in mountain rivers can threaten water resources, biodiversity, and the recreational values provided by them. The first step towards evaluating and then mitigating these risks is the systematic collection of reliable and spatially uniform data on the amount and type of macroplastics deposited in different land covers occurring in a mountain river channel. To maximise the opportunity for the large-scale collection of such data using the citizen science approach, we propose in this study an illustrated step-by-step guide to sample the macroplastic deposited along mountain rivers and to record the collected information using a photo taken by smartphone and a simple online form. Our guide includes three steps: (i) the location of sampling plots across 3–4 predefined surface covers occurring in mountain rivers of temperate climate, (ii) the hand collection of macroplastic deposited in them, and (iii) the photorecording and archiving of information on macroplastics c...
The water depth and flow velocity of a river may be temporarily disturbed by the water level fluc... more The water depth and flow velocity of a river may be temporarily disturbed by the water level fluctuations connected with the operation of artificial dam reservoirs located downstream (so-called backwater fluctuations (BF)). In this research, we use the two-dimensional hydrodynamic model iRIC MFlow_02 to quantify the effects of BF on the lowermost section (ca. 1.5-km length) of a small (channel width ≤ 20 m) mountain stream, the Smolnik Stream, which flows into the Rożnów Dam Reservoir, in Southern Poland. To reproduce the hydrological conditions generally observed in the stream, six scenarios were simulated, considering three steady flow discharges at the inlet, with recurrence intervals of 1 year (1.8 m3 s−1, small flood), 2 years (24.5 m3 s−1; medium flood), and 20 years (89.5 m3 s−1; large flood), and two reservoir levels at the outlet: 265 m a.s.l. (normal reservoir water level) and 270 m a.s.l. (maximum reservoir water level). In these simulations, sediment transport and morpho...
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