Oceanographic Conditions and Human Factors on the Water Quality at an Amazon Macrotidal Beach

• Published in: Journal of coastal research 2012-11, Vol.28 (6), p.1627-1637
• Main Authors: Pereira, Luci Cajueiro Carneiro, Pinto, Ketellyn Suellen Teixeira, da Costa, Kelli Garboza, Vila-Concejo, Ana, da Costa, Rauquírio Marinho
• Format: Article
• Language: English
• Subjects: Amazon; anthropogenic activities; Beaches; Boundary element method; Chlorophylls; Coastal; coastal zone; COM; Dry season; Dry seasons; Eutrophication; Human factors; Hydrodynamics; Mathematical analysis; Media; Natural conditions; Precipitation; Rain; Rainy season; Rainy seasons; RESEARCH PAPERS; Salinity; Sea water; Seasonal variations; Seasons; sewage; Sewage disposal; Tidal currents; Tidal range; Turbidity; Water quality; Water temperature; Wave height; Waves; Weather forecasting; Wind
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/JCOASTRES-D-11-00032.1

Pereira, L.C.C.; Pinto, K.S.T.; Da Costa, K.G.; Vila-concejo, A., and Da Costa, R.M., 2012. Oceanographic conditions and human factors on the water quality at an Amazon macrotidal beach. Atalaia beach is situated in the NE of the Brazilian state of Pará and is one of the most popular with tourists and local beachgoers. This paper describes the seasonal variation in the meteorologic and oceanographic characteristics of the study area, as well as the effects of the lack of a public sanitation system on the quality of the water used by beachgoers. Oceanographic campaigns were carried out between November 2008 and September 2009. The study area is characterized by high rainfall rates (>1900 mm during the rainy season), NE winds with mean speeds of up to 4.36 m/s in the dry season and 3.06 m/s in rainy season, macrotidal conditions (tidal range >4.0 m), moderate tidal current speeds (up to 0.5 m/s), and significant wave heights up to 1.5 m. Water temperature was relatively homogeneous (27.6°C to 29.3°C). Salinity varied from 5.7 (June) to 37.4 psu (November). The water was well oxygenated (up to 9.17 mg/L), turbid (up to 118 nephelometric turbidity units), alkaline (up to 8.68), and eutrophic (maximum of 2.36 µmol/L for nitrite, 24.34 µmol/L for nitrate, 0.6 µmol/L for phosphate, and 329.7 µmol/L for silicate), and it presented high concentrations of chlorophyll a (up to 82 mg/m3). The natural conditions observed in the present study indicate the need for a review of the hydrologic criteria used for the evaluation of beaches by national and international agencies and their adaptation to the reality of the Amazon Coast. The lack of a public sanitation system has led to bacteriologic contamination and the loss of water quality. A praia de Atalaia está situada no nordeste do estado do Pará (Brasil), e é uma das mais turísticas e populares praias do litoral amazônico. O objetivo deste trabalho foi descrever as variações sazonais das condições meteorológicas e oceanográficas da área estudada, bem como conhecer os efeitos da falta de um sistema público de saneamento básico sobre a qualidade da água utilizada para banho pelos usuários desta praia. Campanhas oceanográficas foram realizadas entre novembro de 2008 e setembro de 2009 e dados meteorológicos foram fornecidos pelo Instituto Nacional de Meteorologia. Os resultados mostraram que a área de estudo é caracterizada por possuir altas precipitações (>1900 mm durante o período chuvoso), ventos de nordeste com velocid