- The National Government for allowing the denounced situation to occur in a navigable and inter-jurisdictional waterway, over which it is empowered to regulate and control, according to Article 74, paragraphs 10 and 13 of National Constitution.
- The Province of Buenos Aires for having original dominion over the natural resources within its territory, as established by articles 121 and 124 of the Fundamental Law.
- The Autonomous City of Buenos Aires in its capacity as proprietor of the Riachuelo River, which constitutes a public domain resource within its jurisdiction. The City is obligated to equitably and reasonably use its waters and other river resources, along with the riverbed and its subsoil, without causing appreciable harm to the river’s other proprietors. These obligations are a result of the city’s jurisdiction over its coastal islands, within the scope of the Rio de la Plata treaty, and because Article 81 of the local Constitution mandates the preservation of the flora and fauna within the river’s ecosystem.
- 44 adjacent businesses for having dumped hazardous waste directly into the river, for failing to constructed waste treatment plants, for failing to adopt new technologies, and for failing to minimize the risks of their activities
On June 20, 2006, the Supreme Court of the Nation ordered the defendants to submit a clean-up plan for the river basin, as well as requesting reports from the businesses detailing the measures they would take in order to halt and then reverse pollution in the area.
On September 5, the first public hearing was held, in which the National Government, together with the Provincial Government of Buenos Aires and the Government of the City of Buenos Aires, presented the Riachuelo River Basin Clean-Up Plan, and the creation of an inter-jurisdictional Committee of the River Basin. At the second hearing, conducted one week later, the Environment and Natural Resources Foundation (FARN) declared on behalf of the four NGOs(CELS, Greenpeace, and the Boca Neighborhood Association) their role as a third-party, with emphasis on issues relating to the manner of response to the various State plans, the role of the Court, clean-up assistance, and liability for the environmental damage.
Subsequently, in February of 2007, the Second Public Hearing took place, in which the Secretary of the Environment, Romina Picolotti, explained in front of the Supreme Court the progress made since the presentation of the Matanza-Riachuelo River Basin Clean-Up Plan six months earlier. In turn, the Supreme Court of the Nation decided to appoint independent experts from the University of Buenos Aires in order to conduct a feasibility report on the Clean-Up Plan.
It is important to highlight that the Environment and Natural Resources Foundation (FARN) had, on two occasions, requested from the Supreme Court the incorporation of an expert technical body to conduct an independent assessment that would permit an objective evaluation of the information presented by the authorities, and that would assist the tribunal in tracking the various measures adopted for the Riachuelo clean-up.
The Supreme Court of the National decided to convene a new public hearing in July of 2007, in which each of the relevant parties expressed their opinions and observations of the Matanza-Riachuelo River Basin Clean-Up Plan, which had been presented in 2006, as described above. The experts from the University of Buenos Aires expressed strong criticism of the Plan.
Between November 28 and 30, 2007, the Supreme Court of the Nation convened a new phase of public hearings in which the defendants replied to the initial claim. The vast majority of the 61 defendants (the National Government, the Provincial Government, the City of Buenos Aires, other municipalities, and the businesses) used the opportunity to speak. Each defendant attempted to separate himself from the current river basin pollution, while shifting the blame to the other parties involved. Meanwhile FARN maintained the claim that the Court should adopt urgent measures aimed at addressing the health of the people that suffered as a direct result of the pollution.
Finally, on July 8, 2008 the Supreme Court handed down the landmark decision ion the case “MENDOZA BEATRIZ SIVILIA AND OTHERS V/ NATIONAL GOVERNMENT AND OTHERS IN REGARDS TO DAMAGES (Damages stemming from the environmental contamination of the Matanza-Riachuelo River). The decision determined the liability that corresponded to the National Government, the Province of Buenos Airs, and the City of Buenos Aires, in terms of the restoration from and future prevention of environmental damage in the river basin.
The decision determined who was responsible for carrying forward the actions and clean-up projects and the deadlines to complete those projects, while leaving open the possibility of levying fines on the President of the Matanza-Riachuelo River Basin Authority (ACUMAR) for incompletion.
Moreover, in an innovative and positive step, the highest tribunal has instructed the National Ombudsman and the NGOs who participated in the case (with FARN among them) to form a Chartered Body, which will exercise control over the Clean-Up Plan. This will boost public participation and citizen control in a matter of great social concern such as the Riachuelo Clean-Up.