The aim of this paper was to evaluate the status and trends of water quality in a stressed coastal lagoon in Cartagena, Colombian Caribbean. The water quality data over an eight-year period was analyzed. The study was focused on water parameters as dissolved oxygen (DO), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), salinity, pH, total dissolved solids, total coliforms (TC), ammonium (NH4 +) and total phosphorus (TP). The analysis was conducted in line with Colombian national water standard. Results showed that BOD5, COD and phosphorus are out of the limits for this variables in Colombia. Principal components analysis detected four components that explain 70 % of the variance of data and showed that anthropogenic and temporal factors might be affecting the variation. 1340 Ildefonso Baldiris-Navarro et al.

Coastal lagoons are one of the most threatened ecosystems in the world, because of population growth, habitat destruction, pollution, wastewater, overexploitation and invasive species which are the main causes of their degradation. The objective of this paper was to evaluate the water quality behavior in a stressed coastal lagoon in Cartagena, Colombian Caribbean. Environmental data was analyzed using hypothesis testing, confidence intervals, and also Principal components analysis (PCA). The study was focused on water parameters such as dissolved oxygen (DO), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), salinity, pH, total dissolved solids, total coliforms (TC), Fecal coliforms (FC), ammonium (NH4+) and total phosphorus (TP). The analysis was conducted in line with the Colombian national water standard. Results showed that BOD5, COD, phosphorus, and coliforms are out of the limits for these variables in Colombia and are reaching levels that may be a threat to human health. Principal components analysis detected five components that explained 79.4% of the variance of data and showed that anthropogenic and temporal factors might be affecting the variation of the parameters.