Matanza-Riachuelo River is the main provider of drinking water to the city of Buenos Aires, despite being one of the most polluted rivers in South America.

Buenos Aires is one of the biggest cities in South America with approximately 2,9 million inhabitants it was first built during the 16th century and has been the capital of Argentina since its independence in the early 19th century.

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The River is composed of the tributary streams Morales, Rodríguez, and Cañuelas and drains directly in the estuary de La Plata River. The basin covers an area of 2300 km2 where the upper part is dominated by agriculture activity, both meat and crop production such as dairy, grain, tobacco, wool and leather products. The mid- and lower basin is more urbanized with approximately 5 million inhabitants and many industries, around 15 000 as well as dump sites located in the close vicinity of the river. The main industries in the area is automobile manufacturing, oil refining, metalworking, machine building and the production of textiles, chemicals, clothing and beverages

 

As a consequence pollutants are entering the river from several sources: dump leaches, urban runoff, industrial, municipal wastewater as well as agricultural run-off. High concentration of heavy metals, organic matter, PAHs has been detected in both the water column and the river sediments. The contamination of the river has generated in a bad aquatic status and mutagenic characteristics have been observed in organisms. Not only are the aquatic life suffering from the pollutants and insufficient water quality, but it has implications for the people dependent on the water as drinking water. The pollutants detected can cause chronic health problems and many substances found is known to be cancerogenic and genotoxic.  

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In the basin lives 4,884,823 people in an area of 2,100 km2 meaning 87% of the basin is urban areas (Fernández Cirelli & Ojeda, 2006). Currently is the national government controlled company Agua y Saneamiento (AySA) in charge of water related issues in the region, the company is one of the world's largest water service facilitator (The World Bank, 2012) The Supreme Court in Argentina ordered the Government, the City of Buenos Aires as well as the province of Buenos Aires to start a cleanup program in 2008. The newly set up organization Autoridad del la Cuenca de Matanza Riachuelo (ACUMAR) were decided to coordinate the project. ACUMAR have since 2010 started surveying some of the most polluting industries in order to formulate and implement pollution control plans. In 2011 were 1,507 industries declared as “pollution sources” and 84 % of them have presented a plan to decrease their environmental impact. ACUMAR is also assisting small and medium sized industries with financial and technical support. Another part of ACUMAR’s work is to actively remove pollutants and perform restoration. So far have 114 tons of solid waste been removed from the river. Relocation of low-income inhabitants living along the river and providing many of them with new housing (The World Bank, 2012). The program has 7 points of improvement; Providing Public information, Controlling Industrial Pollution Control, Closing Unsanitary Solid Waste Dumps, Constructing Water Supply, Drainage, and Sewerage Networks, Improving the River Banks, Attending to the Environmental Public Health Crisis, Enforcing and Monitoring the Implementation of the Court Ruling (world bank).

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AySA has with the founding of the World Bank conducted a “wastewater treatment master plan”. In their treatment plan which they aim on implementing by 2020 they intend to treat wastewater in two pre-treatment plants as well as set up smaller urban secondary treatment facilities. AySA has carried out some modeling studies which, indicated that partially treated wastewater has a very small impact on the overall water quality in Rio de la Plata. The aim of our decision support modelling is to through analytical and synthetic modelling determine to what degree changes in industry discharge could potentially influence the water quality and compare the magnitude of change (The World Bank, 2012).