Effects of River Pollution on Its Biota: Results from a 20-Year Study in the Suquía River Basin (Córdoba, Argentina)

The presence of numerous and diverse pollutants and natural toxins has been reported in the Suquia River Basin over 20 years. The fate of these toxic compounds can be mainly attributed to anthropic activities, starting with the release of nutrients from untreated sewage, causing eutrophication, cyanobacteria, and cyanotoxins in the upper basin, followed by poorly treated city sewage, which results in high loads of both inorganic and organic contaminants at the end of the middle basin. Last, but not least, intensive agriculture contributes with agrochemicals and veterinary medicines in the low river basin. Consequently, the inhabiting biota is exposed to a complex mixture of xenobiotics and natural toxins. In this chapter, we discuss on the deleterious effect caused by these toxic compounds on this biota, including the uptake, organ distribution, bioaccumulation, variations in different endpoints (biomarkers), and even changes at community level observed in some cases. The main goal of this chapter is to present a typical basin from a developing country in Latin America, showing both augmented levels and increased sophistication of pollutants found throughout the studied period. Unfortunately, this is a quite common situation in other developing countries, not only from Latin America; thus, this chapter could serve as a guide for future studies in other river basins affected by a complex contaminant mixture elsewhere.