Abstract The Itaqui Port Complex (northeastern Brazil) is one of the largest Brazilian port facilities, whose effluents and waste are dumped directly into the estuarine waters. Although environmental monitoring has been a concern around this site, there has been no toxicogenetics study on organisms living in this environment. Thus, we assessed the toxicogenetics potential of the estuarine waters surrounding Itaqui, using the native catfish Sciades herzbergii as a biomonitor. We found a significantly higher frequency of genetic damage and mutations in the animals collected near to Itaqui in both seasons compared to the reference site (distant from Itaqui with no port activities). We also quantified chemical elements in the surface water and sediments near the port and found that clorine, phosphorus, zinc, and boron were above the limits set by the Brazilian legislation. We suggest that such contaminants are involved in the origin of DNA damage. Moreover, we recommend including toxicogenetics assays in the environmental monitoring of pollutants, as well as in the definition of their allowable limits, as they could be used as law enforcement tools and help to predict large-scale contamination events associated with port activities.

The distribution of phytoplankton in a coastal gradient located in the pelagic area of the Maranhão continental shelf was analyzed. Samples were collected in six bimonthly campaigns with seven sampling stations from November 2013 to September 2014. Simultaneously, environmental parameters were obtained, such as rainfall, salinity, conductivity, pH, dissolved oxygen, suspended particulate matter (SPM), water temperature, water transparency, nitrite, phosphate and silicate concentrations. The values of SPM showed a decreasing profile toward the ocean. The nutrients showed a clear seasonal cycle. The pH maintained alkaline during all the study period. There was an increase in electrical conductivity in direction of the ocean, the same pattern was observed for salinity. Chlorophyll-a concentration presented the highest values during the dry season and the lowest in the rainy one. The total chlorophyll-a also showed a decreasing profile toward the ocean in both dry and rainy season and was very low if compared with other studies in northern Brazil. The scenario observed in this study showed a clear seasonal cycle, with the highest contribution of the phytoplankton in the dry period; also it was observed the predominance of the Bacillariophyta division over the other identified divisions found, based on the obtained qualitative data.

Se analizó la distribución de fitoplancton en un gradiente costero situado en la zona pelágica de la plataforma continental del Maranhão. Las muestras se colectaron en seis campañas bimestrales con siete estaciones de muestreo entre noviembre 2013 y septiembre 2014. Simultáneamente, se obtuvieron diferentes parámetros ambientales, como pluviosidad, salinidad, conductividad, pH, oxígeno disuelto, material particulado en suspensión (MPS), temperatura, transparencia y concentraciones de nitrito, fosfato y silicato. Los valores de MPS mostraron un perfil decreciente en dirección al océano. Los nutrientes mostraron un claro ciclo estacional. El pH se mantuvo alcalino durante todo el período de estudio. Se determinó un aumento en la conductividad eléctrica en dirección al océano y un patrón similar se observó para la salinidad. La concentración de clorofila-a presentó los valores mayores durante la estación seca y los menores en la lluviosa. La clorofila-a total también mostró un perfil decreciente en dirección al océano en las estaciones seca y lluviosa, y fue muy baja en comparación con otros estudios realizados en el norte de Brasil. El escenario observado en este estudio mostró un claro ciclo estacional, con la mayor contribución de fitoplancton en el período seco; también se determinó el predominio de la división Bacillariophyta sobre las otras divisiones identificadas, según los datos cualitativos obtenidos.