Review Of Ecotoxicological Studies Of The Marine And Estuarine Environments Of The Baixada Santista (São Paulo, Brazil)

BRAZILIAN JOURNAL OF OCEANOGRAPHY, 62(2): 133-147, 2014 REVIEW OF ECOTOXICOLOGICAL STUDIES OF THE MARINE AND ESTUARINE ENVIRONMENTS OF THE BAIXADA SANTISTA (SÃO PAULO, BRAZIL) Eduinetty Ceci Pereira Moreira de Sousa1, Letícia Pires Zaroni1, Marcia Regina Gasparro1,* and Camilo Dias Seabra Pereira2 1 Instituto Oceanográfico da Universidade de São Paulo (Praça do Oceanográfico, 191, 05508-120 São Paulo, SP, Brasil) 2 Universidade Santa Cecília (Rua Oswaldo Cruz, 277, 11045-907 Santos, SP, Brasil) *Corresponding author: http://dx.doi.org/10.1590/S1679-87592014063006202 ABSTRACT The aim of the present study was to identify, through ecotoxicological assays, the most critical areas in the Baixada Santista area by compiling scientific papers and technical reports of the state environmental agency. Sediment samples were assessed employing Tiburonella viscana, Leptocheirus plumulosus, Nitokra sp., and embryos of Lytechinus variegatus and Perna perna. Water column samples were assessed by using Vibrio fischeri and Lytechinus variegatus. A total of 217 samples were compiled. It was found that the frequency of acute toxicity was higher in integral sediment samples from the Santos Channel (70.68%) and the lowest frequency was obtained for Bertioga beach samples (15%). Sediment from the Santos and São Vicente Channels, Santos Bay and the area for the disposal of dredged material are the places most affected, whereas the beaches of Guarujá and Bertioga presented low levels of toxicity. No ecotoxicological studies were found in Mongaguá, Itanhaém or Peruíbe cities. RESUMO O objetivo deste trabalho foi identificar, através de ensaios ecotoxicológicos com amostras ambientais, as áreas mais críticas na Baixada Santista compilando trabalhos científicos e relatórios técnicos do órgão ambiental estadual. Para o sedimento foram utilizadas espécies como Tiburonella viscana e Leptocheirus plumulosus, Nitokra sp, embriões de Lytechinus variegatus e de Perna perna. Para a coluna de água foram realizados ensaios com Vibrio fischeri e Lytechinus variegatus. No total foram compiladas 217 amostras. Verificou-se que a frequência de toxicidade aguda foi maior nas amostras de sedimento integral do Canal de Santos (70,68%), e a menor frequência foi obtida para as praias de Bertioga (15%). O sedimento do Canal de Santos, Canal de São Vicente e Baía de Santos e da área de descarte do material dragado foram as regiões mais afetadas, enquanto que as Praias de Bertioga e Guarujá foram as de menor frequência de toxicidade. Não foram identificados estudos para os municípios de Mongaguá, Itanhaém e Peruíbe. Descriptors: Toxicity tests, Baixada Santista, Amphipods, Copepods, Sea urchin and mussel embryos, Bacteria. Descritores: Ensaios ecotoxicológicos, Baixada santista, Anfípodos, copépodos, Embriões de ouriçodo-mar e mexilhão, Bactéria. INTRODUCTION Over the course of the history of humanity, coastlines have been the areas most sought for human settlement. Currently approximately 60% of the world's population lives in coastal areas (LINDEBOOM, 2002). Social and economic developments have affected marine environments, resulting in changes in biogeochemical cycles, in the capacity for the production of biomass, loss of diversity, among other problems (NEVES et al., 2008). The Baixada Santista (an area of 2,422 km2 extending from 24°24’20”S 47°00’18”W to 23°45’30”S 45°52’14”W) covers nine coastal municipalities: Bertioga, Guarujá, Santos, São Vicente, Cubatão, Praia Grande, Mongaguá, Itanhaém and Peruíbe. This area had a population of 1.7 million in 2010, which could double during summer. The Baixada Santista also has one of the largest mangrove areas in the São Paulo state, with a vast stretch of sand bar. The environmental sanitation agency of the São Paulo State (CETESB - Companhia de Tecnologia de Saneamento Ambiental) has been conducting 134 BRAZILIAN JOURNAL OF OCEANOGRAPHY, 62(2), 2014 studies in the Santos/São Vicente Bay and estuary since 1970. These studies have found that this is one of the most eutrophic regions in the world, with high primary production rates, high availability of nutrients and contamination by fecal coliforms in areas near the beaches and estuary, as well as contamination by metals (Hg and Pb) (CETESB, 2004). In the 1980s, CETESB carried out a new study of the area, including in its scope water, air, soil and vegetation, and its results indicated that the entire bay and estuary were in a critical condition due to the unusually high levels of metals. A study on the quality of the water initiated in the late 1990s indicated a considerable decrease of some contaminants, although Hg, halogenated aromatic compounds, and pesticides were found in sediment and organisms. The toxicity tests had not thus far been employed. Over the last two decades, urban and port development has caused a considerable increase in the discharge of pollutants, and currently some of the cities in the Baixada Santista monitor the quality of their coastal waters, especially their suitability for bathing. Some of them, such as Praia Grande, Guarujá and Santos, have submarine sewage outfalls which have brought considerable improvement to water quality. The submarine outfalls improve the water quality at the beaches, but they are a source of pollutants such as surfactants, pharmaceuticals, metals, organic material, and other compounds to the bay. The precipitation of solids around the diffusers area may result in toxicity as well as alteration in the composition of the benthic fauna (ABESSA et al., 2005; BORGES et al., 2008; CORTEZ, 2010). The levels of xenobiotics can be measured in sediment and water column, but their biological effects cannot be assessed by chemical analysis, so ecotoxicological assays are helpful for assessing pollutant bioavailability and its effects in the aquatic environment (POWER & CHAPMAN, 1995). Ecotoxicological assays are procedures employed as a tool for the assessment of the harmful effects of single chemical substances, complex mixtures and environmental samples on previously selected organisms (RAND et al., 1995). The application of ecotoxicological assays to assess the toxicity of effluents and environmental samples began in Brazil in the late 1980s. One of the first applications of toxicity tests to environmental samples of water and sediment from the Santos region was carried out by RACHID (1996) around the Santos submarine sewage outfall, and another by ABESSA (1996) in sediment from the Santos/São Vicente Bay and estuary. This study presents a broad review of the ecotoxicological assessments performed in the Baixada Santista region, as well as identifying critical areas that should be subjected to monitoring, remediation and further studies. MATERIAL AND METHODS This review includes only scientific studies undertaken by universities and research institutes, and technical reports from CETESB, obtained between 1996 and 2011. It does not include data from studies carr (...truncated)