Geochemical and Ecotoxicological Evaluation of an Estuarine Sediment Section at Pacoti River/Ce, Brazil

Abstract

Pacoti estuary is located on the East coast of Ceará State/Brazil and is influenced by several sources of pollution. The sediment quality in three sampling stations was evaluated through an integrated approach. The sediments obtained were analyzed geochemically with respect to texture, organic matter, phosphorus, nitrogen and concentration of metals (Fe, Pb, Cu and Zn). Additionally, the metal loading in the sediment was determined considering a toxic risk quotient (RQ) and enrichment factor (EF). The ecotoxicological approach consisted of acute and chronic toxicity tests with species of marine invertebrates. The geochemical and ecotoxicological data were integrated using qualitative and technical criteria for multivariate analysis. The analyses showed a moderate change in the quality of the sediment Pacoti and there are influences of different contaminant sources. For this reason, one cannot disregard the input of other contaminants, not measured in this study, which probably may also have been relevant for sediment toxicity. Nonetheless, the data suggest that Pb and Cu metals as well as N tended to quality degradation in depositional areas and the sediment had some influence on the biological effects observed. KEYWORDS:

Review on metal contamination in equatorial estuaries in the Brazilian Northeast

“…Industrial discharges have commonly caused contamination by As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in nearshore sediments, river channels, and coastal zones (Li et al, 2013;Souza and Silva, 2016), but the low industrialized nature of the EBZN decreases the relative importance of these sources. The emission factor determined by Vaisman and Lacerda (2003) also suggests coal burning as a significant source of As and Hg.…”

“…In the metropolitan region of Fortaleza city (MRF), the Pacoti River, one of the most pristine in the metropolitan region, was initially not impacted by Zn, Cu, and Hg contents in estuarine sediments (Aguiar, 2005;Vaisman et al, 2005). However, this has changed in more recent years, with an evident accumulation of Fe, Cu, Pb, Zn, and Hg (Rios et al, 2016;Souza and Silva, 2016) due to intensive metal load in the misuse of water resources, whether by tourist activities and deforestation in the region previously covered by dunes and mangroves. Also in the MRF, the urbanized Cocó River exhibited Hg concentrations in bottom sediments about 112 times higher upstream than downstream of the estuarine mixing zone (Vaisman et al, 2005;Almeida, 2015).…”

Impact of anthropogenic activities on an urban river through a comprehensive analysis of water and sediments

“…After being released into the environment, heavy metals can be distributed to the soils, sediments, and surficial waters. Then, metals can be recycled by chemical and biological processes or may be incorporated by the biota and easily propagated through the trophic chain (Maceda-Veiga et al 2012;Souza and Silva 2016). Urban river quality monitoring programs are necessary in order to protect public health and to safeguard water resources.…”

Geochemical and ecotoxicological evaluation of sediments of a semiarid estuary on the northeast of Brazil (Natal / RN)

“…Marine copepods, including Nitocra sp. (Marangoni et al, 2011;Krull et al, 2014;Souza and Silva, 2016) have been widely used to assess sediment toxicity (Souza-Santos et al, 2015).…”