El Comité puede requerir, en las Condiciones de la Competencia, que los bastones que el jugador lleve deben cumplir

Rivers are the principal mean of transportation of plastic waste to the sea. All the plastic waste that we have referred (municipal solid waste, construction and demolition waste, pellets and other industrial and agricultural waste, microbeads, textile fibres and other primary or secondary microplastics) can be introduced into marine environments by rivers and streams, regardless of the distance between the water source and the local where the waste was produced. Accordingly, since the 1980s it is known that 88 billion tons of water are estimated to pour from the rivers of the world into the oceans on average every day, carrying eleven and one-half million tons of dissolved matter into the ocean.423

Therefore, it is not surprising that some studies report the presence of macro and microplastics in continental waters, in both sediments (predominantly lakeshores but also riverbanks) and water samples (predominantly surface water of lakes and rivers). There are in fact few studies, but they are sufficiently clear to demonstrate that freshwater ecosystems also act, increasingly, as a sink for plastic particles – sometimes in densities comparable to the sea plastic particles –,424 and pose a threat to the environment almost as great as plastic in the sea. That said, it is of utmost importance to elucidate the fate, fluxes, and some of the impacts of microplastics in lakes and rivers.

In Geneva Lake, in Switzerland, macroplastics and microplastics (primary and secondary, with about eleven years) have been found in significant quantities on the beaches and in the lake surface: fibres, pellets, hard plastics and polystyrene. Polystyrene was the most abundant and was also found largely in seagull faeces throughout the lake’s coasts.425 A posterior study showed that microplastic concentrations varied from 2,656.25 to 5,018.75

422 _{Marcus Eriksen, ‘The Plastisphere..., 156-7.}

423 _{Gerard J Mangone, Law for the World Ocean: Tagore Law Lectures (Stevens & Sons, London, 1981) 2.} 424 _{Alexander G J Driedger and others, ‘Plastic Debris in the Laurentian Great Lakes..., 10.}

425 _{Florian Faure and others, ‘Pollution due to Plastics and Microplastics in Lake Geneva and in the Mediterranean}

particles/m2_{, far greater numbers than the highest concentration reported in lakeshore}

sediments of Lake Garda.426

Lake Garda, in Italy, totalled at the north shore of the lake, according to a 2013 study, 483 ± 236 macroplastic particles/m² and 1,108 ± 983 microplastic particles/m². Since the lake is located close to remote alpine areas, the study predicted that contamination with plastic debris may be of even higher significance in Italian low-land lakes and streams. Nevertheless, this lake is one of northern Italy’s most popular tourist destinations, so most waste derived from post-consumer products: cigarette filters, food wrappers and containers. This situation is particularly worrying because the lake is used as a drinking water supply. It has also been shown that a wide range of freshwater invertebrates of different feeding guilds had ingested microplastics, that are visible in their entire gut system.427

The Great Lakes of North America have also been surveyed for plastic pollution. Two studies428 revealed that plastic debris – microplastic beads, pellets, waste from beachgoers, shipping and fishing activities – was present in each of the five lakes and that, along the shorelines, they comprised more than 80% of anthropogenic litter. In certain areas, surface water densities of plastics were as high as those reported for areas of litter accumulation within oceanic gyres, perhaps because these lakes have been polluted since the beginning of plastic mass production. According to the researches, there was a much greater percentage of <1mm microplastic debris in the surface waters of the Great Lakes (81%) comparatively to five other marine and freshwater studies: <1mm plastic pellets represented 58% of the lakes’ plastic debris; instead, <1mm plastic debris represented less than 1% of the debris in the North and South Pacific Gyres, while fragments represented 73% and 94%, respectively.

With an average microplastic density of 20,264 particles/km2, Lake Hovsgol, in Mongolia, is more heavily polluted than the Great Lakes. Lake Hovsgol is characterised by low population density, lack of industry and agriculture and non-existence of modern wastewater or sewage treatment facilities. Lake Hovsgol’s high-level of microplastic pollution is thus resultant of the lack of a modern waste management system, as evidenced

426 _{Rachid Dris and others, ‘Beyond the Ocean: Contamination of Freshwater Ecosystems with (micro-) plastic}

Particles’ (2015) Environmental Chemistry 6.

427 _{Hannes K Imhof and others, ‘Contamination of Beach Sediments of a Subalpine Lake with Microplastic}

Particles’ (2013) 23(19) Current Biology 867.

428 _{Alexander G J Driedger and others, ‘Plastic Debris in the Laurentian Great Lakes..., 9, 10 and 14, and Marcus}

Eriksen and others ‘Microplastic Pollution in the Surface Waters of the Laurentian Great Lakes’ (2013) 77(1-2) MPB 177-82.

by the predominance of household plastics, in the form of micro and macroplastic, existent in the lake and its shorelines. In fact, lots of household plastics (fragments and films), a few pellets and no plastic microbeads were observed, especially in the most populated and accessible section of the lake. So, according to the researchers, these facts and figures demonstrated that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics. The study concluded saying that there are laws and plans in place to regulate waste management and reduce waste production in Mongolia, but the infrastructures are almost non-existent.429

With respect to rivers, Thames River is actually a vehicle of trash. In 2012, during a three-months-period, waste was collected at seven localities in the upper Thames estuary. As a result, 8,490 submerged plastic items were intercepted in eel fyke nets anchored to the river bed. The items were plastic cups and cutlery, food wrappers, tobacco packaging, sanitary products (representing over 20%, and containing sanitary towels and condoms), plastic bags and other plastic items. Fortunately, for many years the Port of London Authority collected around 250 tonnes of debris each year. In addition, various clean-up programmes regularly remove large quantities of litter from the foreshore and riverbed of the Thames tidal at low water, preventing some waste from entering the sea.430

Danube River is also polluted by plastic. A scientific study revealed that plastic abundance in this river was of 316.8 ± 4,664.6 items/1,000m3 during the two-year survey between 2010 and 2012. The corresponding plastic input via the Danube into the Black Sea was estimated at 4.2 tonnes/day. Industrial raw materials (pellets, flakes and spherules) accounted for substantial portions (79.4%) of the plastic debris.431 _{This river crosses nine}

borders and its basin extends into the territories of nineteen countries, thus being considered the most international river basin in the world. On that account, an Austrian report highlighted that only international cooperation could cope with the problem of plastic contamination.432 The abundance and composition of floating plastic debris, focusing macroplastic, along the Seine River, in France, was also investigated. Twenty-seven tonnes of plastic debris

429 _{Christopher M Free and others, ‘High-levels of Microplastic Pollution in a Large, Remote, Mountain Lake’}

(2014) 85(1) MPB 156-63.

430 _{David Morritt and others, ‘Plastic in the Thames: A River Runs Through It’ (2014) 78(1-2) MPB 196.}

431 _{Rachid Dris and others, ‘Beyond the Ocean..., 10-1 citing Lechner A and others, ‘The Danube so Colourful: A}

Potpourri of Plastic Litter Outnumbers Fish Larvae in Europe’s Second Largest River’ (2014) 188 Environmental Pollution 177-81.

are intercepted annually by a regional network of floating debris retention booms. A significant proportion of buoyant plastic debris consisted of food wrappers, containers and plastic cutlery.433

Lastly, we cannot forget the most polluted rivers of the world, that certainly transport significant quantities of plastic, mainly macroplastics: Buriganga River, in Bangladesh, where 4,500 tonnes of solid waste is dumped every day; Yellow River, in China, where billion tonnes of sewage and other industrial toxic waste are dumped; Yamuna/Jamuna River, in India, whose water is polluted with sewage, municipal waste and agricultural runoff (fertilisers, herbicides, and pesticides) and industrial activities; Ganges River, in India, where many people dump all their waste; and Citarum River, in Indonesia, known as the world’s most polluted river, receiving effluents (dyes and chemicals) from over 200 textile factories, and also with plastic and other detritus.434

A recent study focusing 240 individual samples from 79 sites near 57 rivers of various sizes around the world, concluded that the quantity of plastic per cubic metre of water was significantly higher in larger rivers than in smaller ones, and that the plastic loads of larger rivers increase disproportionately in relation to the increase of plastic debris available for transport. Furthermore, scientists estimated – using mismanaged plastic waste as a predictor –,435 that the ten top-ranked rivers transport 88%-95% of the global plastic load into the sea. These rivers – Yangtze, Yellow, Hai, Pearl, Amur, Mekong, Indus and Ganges Delta in Asia, and the Niger and Nile in Africa – have two things in common: a generally high population living in the surrounding region, sometimes into the hundreds of millions;436 and a less than ideal waste management process.

433 _{Rachid Dris and others, ‘Beyond the Ocean..., 12 citing Gasperi J and others, ‘Assessment of Floating Plastic}

Debris in Surface Water Along the Seine River’ (2014) 194 Environmental Pollution 163-6.

434 _{For further information, see Golam Kibria, World Rivers in Crisis: Water Quality and Water Dependent}

Biodiversity are at Risk - Threats of Pollution, Climate Change and Dams Development (2016) available at

<www.researchgate.net/publication/263852254_World_Rivers_in_Crisis_Water_Quality_and_Water_Dependent _Biodiversity_Are_at_Risk-_Threats_of_Pollution_Climate_Change_and_Dams_Development>.

435 _{Christian Schmidt, Tobias Krauth and Stephan Wagner, ‘Export of Plastic Debris by Rivers into the Sea’ (2017)}

51(21) EST 12246-53. In short, to predict plastic inputs via rivers into the sea, scientists combined plastic concentrations in rivers with the amount of mismanaged plastic waste generated in the catchments, assuming that the entire river catchment was connected to the coastal sea via the river network.

436 _{The Yangtze is Asia’s longest river and also one of world’s most ecologically important rivers, but is also the}

biggest carrier of plastic pollution to the sea, dumping an estimated 1.5 million metric tons of plastic waste into the Yellow Sea. Its basin is home to almost 500 million people (more than one third of China’s population).