Browsing by Author "Santos, Cristina"
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- Environmental status of water and sediment around submarine outfalls – west coast of Portugal = Qualidade da água e dos sedimentos na zona circundante de oito emissários submarinos – costa oeste de PortugalPublication . Santos, Cristina; Barreiros, M. Alexandra; Pestana, Pilar; Cardoso, Ana; Freire, AlexandreThe sea along the western coast of Portugal presents hydrodynamic conditions that place it among the most favourable of European coastal waters for dilution and dispersion of waste water. Thus it is an appropriate zone for the location of submarine outfalls. According to the European Union Directives and Portuguese Regulations the waste waters produced by this densely populated coast should be treated, therefore 18 wastewater treatment plants with submarine outfalls were built along the coast. Between 2002 and 2004, five sampling campaigns were performed in seven outfalls that were selected to participate in water and sediment quality surveys supported by INAG (Portuguese Water Institute), and performed by the Hydrographic Institute of the Portuguese Navy. The water quality assessment was based on 10 chemical and physical parameters, including heavy metals. The results were compared with reference values and data from the largest flow outfall located at Guia, which has an autonomous monitoring program. In order to evaluate significant differences in water quality between years and sampling sites, statistical analyses were performed. S ediments were evaluated for grain size, heavy metals, PAH, hydrocarbons, chlorinated pesticides and PCB. In order to evaluate the level of pollution of the different areas where the outfalls are located, the concentration factor (CF) (sediment/water elemental concentration ratio) was calculated and compared with the recommended values for the CF of each element. The water sampling program did not allow identifying a clear seasonal evolutionary pattern. The environmental status of the waters surrounding the outfalls discharges comply, to a great extent, with the reference values proposed by INAG and did not revel high levels of contaminants. Due to the low sorptive capacity of the sediment for contaminants, trace metals, hydrocarbons and PAHs have a low environmental impact. The values of the concentration factors for metals are below the recommended values.
- The importance of an extended monitoring program and the WFD requirementsPublication . Santos, Cristina; Barreiros, M. Alexandra; Figueiredo, Zélia; Trancoso, Maria Ascensão; Catarino, Justina; Garcia, Carla; Lopes, Catarina
- Using Operational models and bidirectional tools for management support of water quality monitoring programs:the example of the Guia long sea outfall monitoring programPublication . Garcia, A. C.; Fernandes, L.; Mateus, M.; Santos, Cristina; Catarino, Justina; Quintino, V.; Carvalho, Vânia; Lopes, Carla; Neves, Ramiro
- Water and wastewater monitoring of Guia Submarine Outfall: an 11 year surveyPublication . Santos, Cristina; Catarino, Justina; Figueiredo, Zélia; Calisto, Sandra C.; Marques, Eugénia; Cunha, Pedro; Antunes, MargaridaSANEST is a public sanitation company that manages a wastewater treatment plant located at Guia, on the west coast of Lisbon, Portugal. This company collects and treats the sewage of four municipalities with an estimated 750 000 population equivalent, thus being one of the biggest sanitation companies in Portugal. A Decision of the Commission 2001/720/CE conceded SANEST derogation, exempting it to apply less than secondary treatment to wastewaters discharged into the Atlantic Ocean from the four agglomerations. This decision was supported on a large monitoring program, presented to the EU, and set up by SANEST. It surveys the impact of the effluent disposal and includes measurements of physical, chemical, biological and microbiological properties in the effluent and in the receiving waters. This paper presents methods and results for the effluent chemical and microbiological quality as well as for the receiving waters and an ichthyofauna survey, and resumes an eleven year situation, with the preliminary wastewater treatment before effluent disposal. The WWTP results correspond to medium load urban effluents without treatment with temporal variability related to flood fluctuations. In the receiving waters almost legal values are respected and the plume of the outfall is only identifiable by faecal bacteria in the vicinity of the discharge. The fish community, in particular benthic species, has revealed a slight degradation probably due to the fact that pollutants tend preferentially to accumulate on sediment. The treatment plant is being upgraded to fulfil, by May 2009, an advanced primary treatment level that includes disinfection during the bathing season to fully observe the European Commission Decision 2001/720/EC.