The Pilcomayo has been a focus of environmental concern because of repeated pollution, allegedly caused by the operations of mining companies. In October 2005, a major leak at the Laguna Pampa tailings dam in Potosí, Bolivia, caused 10,000t of sediment and liquid waste to be released, polluting 25km of the Tarapaya river - one of the Pilcomayo's tributaries.
The river is one of the largest in the landlocked nation and its basin covers some 68,000km3, 92.6% of which is in Bolivia.
