Pharmaceuticals as emerging contaminants in the aquatic environment of Latin America: a review.

Pharmaceutical active compounds (PhACs) are environmentally ubiquitous around the world, and the countries of Latin America (LATAM) are not the exception; however there is still little knowledge of the magnitude and conditions of their occurrence in LATAM and of the environmental consequences of their presence. The present work reviews 79 documents published from 2007 to 2019 on the occurrence, concentrations, and sources of PhACs and hormones in surface water (SW), wastewater (WW), and treated wastewater (TWW) in LATAM and on the circumstances of their release to the environment. Research efforts are reported in only ten countries and confirm the presence of 159 PhACs, mainly analgesics and anti-inflammatories, although extraordinarily high concentrations of carbamazepine (830 µg/L) and ethinylestradiol (6.8 µg/L) were found in Ecuador and Brazil, respectively. The analysis of maximum concentrations and the ecotoxicological risk assessment corroborate that (1) these values exceed the environmental concentrations found in other parts of the world, (2) the environmental risk posed by these concentrations is remarkably high, and (3) there is no statistically significant difference between the maximum concentrations found in WW and those found in TWW. The main source of PhACs in LATAM's aquatic environment is WW; hence, these countries should direct substantial efforts to develop efficient and cost-effective treatment technologies and plan and apply WW management strategies and regulations. This analysis presents the current states of occurrence, concentrations, and sources of PhACs in the aquatic environment of LATAM and outlines the magnitude of the environmental problem in that part of the world.

Assessment of groundwater contamination by landfill leachate: a case in México.

In México, uncontrolled landfills or open-dumps are regularly used as "sanitary landfills". Interactions between landfills/open-dumps and shallow unconfined aquifers have been widely documented. Therefore, evidence showing the occurrence of aquifer contamination may encourage Mexican decision makers to enforce environmental regulations. Traditional methods such as chemical analysis of groundwater, hydrological descriptions, and geophysical studies including vertical electrical sounding (VES) and ground penetrating radar (GPR) were used for the identification and delineation of a contaminant plume in a shallow aquifer. The Guadalupe Victoria landfill located in Mexicali is used as a model study site. This landfill has a shallow aquifer of approximately 1m deep and constituted by silty sandy soil that may favor the transport of landfill leachate. Geophysical studies show a landfill leachate contaminant plume that extends for 20 and 40 m from the SE and NW edges of the landfill, respectively. However, the zone of the leachate's influence stretches for approximately 80 m on both sides of the landfill. Geochemical data corroborates the effects of landfill leachate on groundwater.