Historical ecotoxicological assessment of San Juan ecosystem, Santiago de Cuba, Cuba.

Currently, the environmental decision-making related to watershed preservation is oriented under the precepts of an historical environmental assessment. The objective of this research was to conduct a historical ecotoxicological assessment of the San Juan de Santiago de Cuba ecosystem. This was considered a systematic environmental monitoring which ran from 2010 to 2013, made q?uarterly. Physicochemical parameters such as electrical conductivity, total alkalinity, total hardness, pH, total solids, dissolved oxygen, biochemical oxygen demand and chemical oxygen demand were determined. All parameters of environmental risk prediction were performed using the GECOTOX program. The concentrations of Cu, Zn, Pb and Cd on three target organs (brain, gills and liver) in the biomonitor adult Gambusia punctata (Poecilidae) were analyzed. In this species, the effect of total protein and enzymatic activity of acetylcholinesterase as biomarkers were evaluated. In general, the parameters were outside the values set used by the Cuban quality standards. The GECOTOX program said that the waters of the San Juan ecosystem presented a high rate of risk. The highest concentrations of metals were determined in the gills, liver and brain, respectively. Biomarker values w? ere high, being higher for females. Finally, it was concluded that from one year to another all responses were ascending; thus, the San Juan ecosystem presented ecotoxicological effects in time.