Water pollution in the Amazon Basin comes mainly from:

• Illegal/informal mining activities: Despite existing national legislation, illegal mining operations have increased in the past two decades, resulting in the release of an average of about 24 kg of mercury per square kilometer of excavation area into rivers.
• Oil extraction activities: Environmental pollution incidents commonly occur within extraction areas and during the transportation of crude oil to major refineries.
• Domestic, commercial and industrial wastewater: It is estimated that around 1,700,000 tons of waste and 600 liters per second of liquid domestic/urban waste are discharged into the Amazonian rivers.
• River transport: With over 24,000 kilometers of navigable rivers, river transport serves as a vital means of circulation and integration for local populations in the Amazon Basin.

The rapid expansion of grain agribusiness (including crops like soybean, rice, sunflower, sorghum, and corn) and cattle ranching into the interior of the Amazon is a significant driver of deforestation rates. These activities are often accompanied by other factors such as small-scale mining, logging, and infrastructure development. The combined environmental and socio-economic impacts are extensive, including alterations to the hydrological cycle, changes in river and stream beds, and increased risks to food security.

The loss of biodiversity and ecosystems in the Amazon is caused by various factors, including forest destruction, the expansion of agricultural and livestock activities, the use of fertilizers and pesticides, both legal and illegal mining, the extraction and trafficking of species, and the introduction of exotic species. These activities contribute to decreased water availability, loss of ecosystem resilience, and the proliferation of diseases, among other environmental and socio-economic impacts.

Droughts and floods are recurrent phenomena in the Amazon Basin, but their frequency and intensity have increased in recent years due to erosion and climate variability. La Niña events typically result in dry periods in the northern, northeastern, and southern regions of Brazil, while excess rainfall and flooding are often associated with El Niño events.

The Amazon River transports an estimated total of 600 to 800 million tons of sediment annually to the Atlantic Ocean, leading to considerable alterations in coastal ecosystems, particularly in Guyana and Suriname. A significant portion of these sediments originate from the Andes, where erosion is particularly severe.

This sedimentation process results in a reduction of hydrobiological resources and heightened navigation risks. Moreover, it poses sanitation risks due to the degradation of water quality in rivers, canals, estuaries, and coastal marine areas.

In many Amazonian countries, land is used primarily for the expansion of large-scale infrastructure, agro-industrial activities, and extensive cattle ranching. These policies are often driven by the demands of both national and international markets, often at the expense of small-scale local, community, or family-based production. Consequently, this dynamic frequently leads to significant social conflicts and prompts the migration of local populations towards major urban centers.

Over the past forty years, the ongoing process of deglaciation, which started between 1730 and 1750, has accelerated at an unprecedented rate not seen in the last three centuries. Glaciers have experienced a significant loss, ranging between 30% and 50% of their surface area, with the most vulnerable glaciers virtually disappearing altogether.

The primary impacts attributed to glacial retreat include the reduction of water resources, the formation of new lakes, and elevated risks of landslides and avalanches. These phenomena can result in prolonged droughts, desertification, and social conflicts.

Major infrastructure projects in the Amazon Basin carry significant social, economic, and environmental implications for both rural and urban populations. Their direct impacts encompass human displacement, economic and social transformations, the inundation of fertile land, deforestation, loss of fauna, modification of the hydrobiological system and terrestrial ecosystems, alterations in navigability, and specific challenges related to methane pollution, among others.