Resumen El presente trabajo evaluó una serie de parámetros físicos y químicos para determinar la calidad del agua marina en los alrededores de la isla Uvita, Limón, Costa Rica, y determinar la posible influencia de las descargas procedentes del emisario submarino de la ciudad de Limón sobre el entorno marino circundante. Se evaluaron nutrientes (nitritos, nitratos, silicatos, fosfatos y amonio), metales pesados (plomo, cromo, níquel), sólidos (disueltos y sedimentables) y parámetros físicos (pH, temperatura, turbiedad, etc.). La zona de estudio se dividió en segmentos circundantes a la isla y se ubicaron 6 puntos de muestreo alrededor de la misma con el fin de comparar la calidad del agua de las áreas con mayor influencia del emisario con las de menor influencia. Se programaron tres actividades de muestreo: setiembre 2012 (época lluviosa), octubre 2012 (transición lluviosa-seca) y setiembre 2013 (época lluviosa). Los niveles de nutrientes, metales pesados, sólidos y parámetros físicos, se compararon con los reportados en la literatura para el Golfo de México y el Mar Caribe, encontrándose que, en general, eran mayores a los reportados en la literatura. En particular, los datos del último muestreo mostraron un incremento considerable en la concentración de los metales pesados (Pb, Cr y Ni), que podría ser atribuido a factores ajenos a las descargas del emisario como por ejemplo las operaciones portuarias y las actividades antropogénicas industriales, las cuales repercuten en la zona mencionada.

Abstract The present work evaluated a series of physical and chemical parameters to determine the quality of marine water in the surroundings of Uvita island, Limón, Costa Rica, and to determine the possible influence of the discharges coming from the submarine emissary of the city of Limón on the surrounding marine environment. Nutrients (nitrites, nitrates, silicates, phosphates and ammonium), heavy metals (lead, chromium, nickel), solids (dissolved and sedimentable) and physical parameters (pH, temperature, turbidity, etc.) were evaluated. The study area was divided into segments surrounding Uvita island, and 6 sampling points were located around the island in order to compare the water quality of the areas with greater emissary influence with those of less influence. Three sampling activities were scheduled: September 2012 (rainy season), october 2012 (rainy-dry transition) and september 2013 (rainy season). The levels of nutrients, heavy metals, solids and physical parameters were compared with those reported in the literature for the Gulf of Mexico and the Caribbean Sea, finding that, in general, they were higher than those reported in the literature. In particular, the last sampling data showed a considerable increase in the concentration of the heavy metals (Pb, Cr and Ni), which could be attributed to other factors outside the emissary’s discharges such as port operations and industrial anthropogenic activities, which impact on the aforementioned area.

ABSTRACT In this article, a wastewater treatment system is proposed to avoid the pollution problems that can be generated by the water collected by the central sewer system of Havana. The objective is to size a treatment system by means of an underwater outlet as a submarine outfall, for sewage water collected by the central sewerage system of Havana. After collecting the necessary data, the sizing of the different components of the system is presented, analyzing the results of the bacteria removal processes and comparing them with the simulations carried out with the Visual Plumes model. The proposal of the new emissary is based on international recommendations and compliance with the Cuban norm that regulates the quality of the spillage of liquid waste to the sea.

RESUMEN En este artículo se propone un sistema de tratamiento de aguas residuales para evitar los problemas de contaminación que pueden generar las aguas colectadas por el alcantarillado central de La Habana. El objetivo es dimensionar un sistema de tratamiento mediante un emisario submarino, para las aguas albañales conducidas por el sistema de alcantarillado central de La Habana. Luego de colectar los datos necesarios, se presenta el dimensionamiento de los diferentes componentes del sistema, analizando los resultados de los procesos de remoción de bacterias y comparando los mismos con las simulaciones realizadas con el modelo Visual Plumes. La propuesta del nuevo emisario está basada en recomendaciones internacionales y en el cumplimiento de la norma cubana que regula la calidad del vertido de residuales líquidos al mar.

ABSTRACT The work shows the studies carried out to evaluate the behavior of the hydrodynamics, and the wave fields associated with different scenarios, with the aim of defining the boundary conditions, for the subsequent sizing of an underwater outfall that allows the final disposal of the waste waters of Havana in the area called El Chivo beach. Numerical modeling is applied to simulate the behavior of the hydrodynamic and wave variables generated by the astronomical tide and the wind. Six scenarios are defined, three directed to the study of surface currents, and the rest for the study of the waves. The conditions selected for the functional and structural design of the treatment system are presented as a result of the analysis of the simulated scenarios.

RESUMEN El trabajo muestra los estudios realizados para evaluar el comportamiento de la hidrodinámica y los campos de oleaje asociados a diferentes escenarios, con el objetivo de definir las condiciones de frontera, para el posterior dimensionamiento de un emisario submarino, que permita la disposición final de las aguas residuales de La Habana, en la zona denominada playa El Chivo. Se aplica la modelación numérica para simular el comportamiento de las variables hidrodinámicas y del oleaje, generadas por la marea astronómica y el viento. Se definen seis escenarios, tres dirigidos al estudio de las corrientes superficiales y los restantes para el estudio del oleaje. Se presenta, como resultado del análisis de los escenarios simulados, las condiciones seleccionadas para el diseño funcional y estructural del sistema de tratamiento.

Amostras de sedimentos de fundo foram coletadas e analisadas para o mercúrio no Estuário de Santos-SP. Os resultados analíticos foram revistos para contaminação antropogênica de alguns setores da área estuarina como resultado de resíduos petroquímico e metalúrgico derivados do distrito industrial de Cubatão, das atividades siderúrgicas do Estado de São Paulo (COSIPA), do porto de Santos e, finalmente, das descargas dos efluentes do emissário submarino dentro da baía de Santos. Os valores para o fator de contaminação médio (FC) obtidos para os sedimentos de fundo variam de 1 a 3, principalmente para os canais de Santos e São Vicente; entretanto, na baía de Santos, os valores de FC (abaixo de 1) indicam baixa contaminação, exceto na área de descarga do emissário submarino.

Bottom sediment samples were collected and analyzed for mercury in the Estuary of Santos-SP. The analytical results reveal anthropogenic contamination for some sectors of this estuarine area as a result of petrochemical and metallurgical residues derived from the Industrial District of Cubatão, from the activities of the State of São Paulo Siderurgy (COSIPA), from the Santos harbor and, finally, from effluents discharged by the submarine emissary into the Bay of Santos. The values for the factor of contamination (FC) found in the bottom sediments range from 1 to 3, mainly for the channels of Santos and São Vicente; however, in the Bay of Santos the FC values (below 1) indicate low contamination except in the discharge area of the submarine emissary.

Foram realizados experimentos para avaliar previamente o potencial tóxico de duas amostras de efluente derivado de petróleo a ser lançado no canal de S. Sebastião, através de um emissário submarino que está sendo construído no Terminal Marítimo "Almirante Barroso" (TEBAR). As amostras (denominadas Efluente-A e -B) foram fornecidas pela PETROBRÁS e foram testadas com jovens e adultos de Promysis atlântica (Crustacea, Mysidacea). Em relação ao Efluente-A, concentrações entre 1% e 5% alteram significativamente a taxa de mortalidade dos animais em curto intervalo de tempo (24-96 horas). No caso do Efluente-B concentrações de 0,075% (96 horas) estão no limite máximo de exposição que não afeta a sobrevivência dos jovens da mesma espécie. Os testes demonstraram serem as duas amostras (Efluentes A e B) bastante diferentes uma da outra, sendo a segunda cerca de dez vezes mais tóxica que a primeira. Além disso, a toxicidade dos efluentes varia também em função do armazenamento. Outros possíveis efeitos dos efluentes sobre o ecossistema são discutidos.

Preliminary experiments were carried out to estimate the potential toxicity of an effluent derived from petroleum to be dumped into São Sebastião channel through a submarine emissary which is being built at the Maritime Terminal "Almirante Barroso" (TEBAR). Two simulated samples of this effluent (denominated A and B) were supplied by PETROBRÁS. The toxicity of sample A was tested with young and adult Promysis atlántica (Crustacea, Mysidacea) and the toxicity of sample B only with young individuals of the same species. In relation to Effluent-A, concentrations between 1% and 5% increase significantly the rate of mortality of animals in short term tests (24-96 hrs). The results also indicated that, in this case, adults are less resistant than youngs. Concentrations of 0.075% of Effluent-B are at the maximum limits of no effect observation for short term expositions of young animals (96 hrs). The two effluent samples are different from each other. Both of them are very toxic, but the second is about 10 times more toxic than the first one. The toxicity of the samples also varies in function of time of storage. It seems that this variation is not predictable as the results indicated that the toxicity increased with storage for sample A and diminished for sample B. Other possible effects of the effluent on the ecosystem are discussed.