Abstract

 Metals are a concern in the Pánuco estuarine environment, located in the state of Tamaulipas, Mexico. The study area, which is an estuarine system, received wastewater from municipal and industrial sources, which may settle on the bottom and become incorporated into sediment. Nickel and vanadium have been persistent at the study area, both of them could be re-suspended into the environment by dredging and boating activities, and potentially threaten the integrity of the ecosystem.
  Health and biodiversity of estuarine systems depend on the maintenance of high-quality habitat. To asses the environmental quality of those habitat, numerical sediment quality guidelines (SQGs) have been developed using matching chemistry and laboratory toxicity data, but there is no index that could integrate those data. The objective of this study was to create a numerical index called Sediment Quality Index (SQI) that integrated environmental parameters in order to determine the sediment quality of the Pánuco estuarine system. In order to discern its quality, the sediment was characterized, during two seasons, two banks and at the river center. This sampling scheme was implemented in order to find changes between seasons as well as spatial variations.
  Results provided evidence that nickel is accumulating at the bottom sediments, and the best sediment quality is found during the dry season because of the system hydrodynamic conditions and dredging activities. The SQI was able to incorporate physical, chemical, biological and toxicological data, reflecting the environmental condition of the sediment quality. Due to the application of the SQI and its relationship with environmental parameters, its similar tendency with the Infaunal Trophic Index and the SQI being defined as one of the principal factors that explains variance in the system, the SQI is considered as an effective tool for sediment quality evaluation.