Buenos Aires, Argentina

Matanza-Riachuelo

Focus area

A heavily urban river basin in and around Buenos Aires that is the subject of a long-running Supreme Court cleanup order.

Argentina Rivers program

In brief

  • The Matanza-Riachuelo drains a dense industrial basin around Buenos Aires.
  • The World Bank called it Argentina's most contaminated urban river basin; a 2008 Supreme Court order set a cleanup in motion.
  • We focus on supporting local monitoring, waste prevention and community cleanups led by Argentine groups.

The place

The Matanza-Riachuelo drains a densely populated and industrial basin in and around Buenos Aires, crossing 14 municipalities and covering about 2,238 square kilometers. Along its banks are homes, small businesses, factories and, historically, meat-processing and leather works that discharged into the water for generations.

Why it matters

In 2009 the World Bank described the Matanza-Riachuelo as the most contaminated urban river basin in Argentina, home to some 3.5 million people, when it approved a US$840 million loan to support sewerage expansion and other cleanup work. A 2023 report in La Nación put the basin population at 4.5 million, and said sewage effluent remained one of the most important contaminants.

In 2008 the Argentine Supreme Court, responding to a lawsuit by basin residents, ordered governments to improve residents' quality of life, remedy the environmental damage and prevent future harm. In October 2024 the Court ended its supervision of that order, finding its institutional goals met. Several civil society groups have said that many cleanup commitments remain unfinished.

Our focus

Our focus is on supporting locally led work: transparent, repeatable monitoring that local teams can maintain, riverbank and stream-side surveys, waste prevention at the source, and community cleanups organized with neighborhood groups and the cooperatives already working along the shoreline.

Cleanup does not make water safe to drink. Access to safe drinking water is a separate program led by qualified local specialists, with appropriate treatment and regular testing.

Local expertise

FARN (Fundacion Ambiente y Recursos Naturales), Greenpeace Argentina and the Asociacion Ciudadana por los Derechos Humanos (ACDH) are named by the Buenos Aires city government as civil society organizations connected to the Supreme Court's oversight body for the cleanup, alongside CELS and the Asociacion Vecinos de La Boca. FARN describes the Riachuelo as one of its thematic areas, and ACDH was accepted by the Court as an interested third party in the case.

Residents of the basin brought the original lawsuit, and the neighborhood groups and legal organizations around it know this river far better than we do.

Next steps

The next steps are to listen to Argentine environmental, legal, health and neighborhood organizations, learn what monitoring and cleanup work already exists, and find where local teams would welcome extra support.

Organizations to explore

Organization to exploreWorks on this waterway

FARN (Fundacion Ambiente y Recursos Naturales)

Argentina

An independent Argentine civil society organization, active since 1985, working on environmental protection and human rights. Its website lists the Riachuelo as a thematic area, and the Buenos Aires city government names it as one of the civil society organizations in the Cuerpo Colegiado created after the Supreme Court's 2008 ruling to follow the cleanup. In 2025 FARN and other organizations took a complaint about the basin to the Inter-American Commission on Human Rights.

Related focus area: Matanza-Riachuelo

Official website of FARN (Fundacion Ambiente y Recursos Naturales) (external site)

Listing checked October 2026.

Organization to exploreWorks on this waterway

Greenpeace Argentina

Argentina

The Argentine branch of Greenpeace, which describes itself as a nonprofit, independent organization that does not accept donations from governments, companies or political parties. The Buenos Aires city government lists it among the civil society organizations in the Cuerpo Colegiado that follows the Matanza-Riachuelo cleanup, and its own ten-year article on the 2008 ruling comments on the basin and on planned incinerator plants there.

Related focus area: Matanza-Riachuelo

Official website of Greenpeace Argentina (external site)

Listing checked October 2026.

Organization to exploreWorks on this waterway

ACDH (Asociacion Ciudadana por los Derechos Humanos)

Argentina

A multidisciplinary Argentine non-governmental human rights organization, active since 1989, whose programs include environment and water issues. The Supreme Court accepted it as an interested third party in the Matanza-Riachuelo case, and it is listed among the civil society organizations in the Cuerpo Colegiado. Its website carries a series of posts on the Riachuelo, including a 2025 complaint to the Inter-American Commission on Human Rights. It is a rights and advocacy organization rather than a field cleanup group.

Related focus area: Matanza-Riachuelo

Official website of ACDH (Asociacion Ciudadana por los Derechos Humanos) (external site)

Listing checked October 2026.

References

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If you work on or live near Matanza-Riachuelo, we would like to hear what would genuinely help.

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