Environ Monit Assess (2017) 189: 245 DOI 10.1007/s10661-017-5971-x Metal contamination and fractionation in sediments from the lower basin of the Vale do Ribeira (SE, Brazil) Estefanía Bonnail & Lucas M. Buruaem & Lucas G. Morais & Denis M. S. Abessa & Aguasanta M. Sarmiento & T. Ángel DelValls Received: 2 December 2016 /Accepted: 21 April 2017 /Published online: 1 May 2017 # Springer International Publishing Switzerland 2017 Abstract The sediment quality of Ribeira de Iguape analyzed elements, especially for Pb. The station from River is affected by former Pb extraction mining. Some Registro was stressed by Co, Pb and Zn; with Pb under studies affirm the restoration status of the basin, howev- the reactive fraction that could be associated with high er, mobility of metals and its associated risk is still mobility and potential bioavailability. questioned. This study integrates the metal concentra- tions in the lower part of the basin with different con- . tamination source to determine the existence of risks Keywords Iguape River Metal monitoring . associated with the mobile fractions of the geochemical Environmental risk assessment Sequential extraction matrix. Despite concentrations of metals were low and the environmental risk factor values were negative, our results indicated that As, Mn, Pb, and V were present in Introduction the most labile forms. The multivariate analysis con- ducted using metal concentrations, environmental risk The Vale do Ribeira is located on the Southeast of factor values and speciation suggested that any risk Brazil, between Paraná and São Paulo states; it takes would be associated with the labile fractions of the place in very preserved region, which is considered the Atlantic rainforest reserve of the biosphere and connects to the World Natural Heritage site of the Cananéia- E. Bonnail (*) Centro de Investigaciones Costeras–Universidad de Atacama Iguape Estuarine Complex. Its fluvial network was his- (CIC-UDA), Av/ Copayapu n°485, Copiapó, Chile torically affected by former mining activities of lead e-mail: [email protected] extraction, especially the Ribeira de Iguape River (RIR). Although extraction activities ceased in the L. M. Buruaem : L. G. Morais : D. M. S. Abessa Campus Experimental do Litoral Paulista, Núcleo de Estudos 1990s, tailing residues located on the upper part of the sobre Poluição e Ecotoxicologia Aquática, Universidade Estadual basin still represent sources of metals to the aquatic Paulista BJúlio de Mesquita Filho^, Praça Infante Dom Henrique, system (Cunha et al. 2005). Latest investigations have s/n, São Vicente, SP 11330-900, Brazil determined that the basin is under a restoration process A. M. Sarmiento since the metals inputs have decreased and the trawling Department of Earth Sciences, Faculty of Experimental Sciences, of metals associated with particulate matter towards the University of Huelva, Campus ‘El Carmen’, 21071 Huelva, Spain Atlantic Ocean (Cunha et al. 2005;Abessaetal.2012, 2014). Nevertheless, few studies have undertaken the T. Á. DelValls UNESCO UNITWIN/WiCop. Department of Physical-Chemistry. process in the lower part of the basin, where the depo- Faculty of Marine and Environmental Sciences, University of sition of sediments and particles occur and the mobility Cádiz, Campus Río San Pedro Puerto Real, 11510 Cádiz, Spain of metals could be linked to potential toxic risks. 245 Page 2 of 8 Environ Monit Assess (2017) 189: 245 The potential risk of elements is link to the chemical environmental risk was calculated based on freshwater form in the environment, which is governed by physi- sediment quality benchmarks, and integrated to under- cochemical parameters (Hamelink et al. 1994). There- stand potential risk associated with mobility of metals in fore, the chemical form can vary with climatic phenom- the lower part of the basin. ena and other hydrological events in aquatic systems. Due to that, the assessment of the ecological risk is associated with the chemical fractionation. The sequen- Materials and methods tial extraction procedures are widely accepted as appro- priate methods for assessing the speciation of metals in The geomorphology of the valley has been demonstrat- sediments (Tessier et al. 1979; Kestern and Förstner ed as a crucial factor (Abessa et al. 2014)forthedepo- 1986). Metals bound to the first fractions are considered sition of contaminants in the lower part of the river more susceptible to remobilization than metals residing (Moraes et al. 2004) as the river leaves the sloppy zone in the lattices of sediment minerals (Luoma and Davis and starts flowing through a plain area. This sink effect 1983;Ribaetal.2002a). is also incremented by the meanders formation in the The results presented in this work are part of an flooding plain, sequestering contaminants in elbows. integrative approach conducted in the area to assess Sediment sampling stations were situated in the lower the sediment quality. The main objective of this research part of the RIR basin (Fig.1): Sete Barras (SB; 24° 23′ is to determine the possible risks associated with metals 16″ S, 47° 55′ 33″ W) and Registro (REG; 24° 29′ 15″ S, and metalloids in the lower RIR, considering the mobil- 47° 50′ 37″ W). SB is located closer to the mining ity of these elements. To achieve that, the concentration discharges; it is also characterized with strong flooding of some elements (Al, As, B, Ba, Be, Ca, Co, Cr, Cu, Fe, episodes. In contrast, REG is affected by flooding epi- Li, Mg, Mn, Ni, Pb, Sr, Ti, U, V, and Zn) was assessed sodes of many tributaries. Superficial sediment samples plus the geochemical fractionation in sediment deter- were manually collected from the river banks and mined by means of a chemical fractionation analysis transported in dark conditions into plastic recipients using a sequential extraction procedure. The potential with a layer of water from the adjacent river. A third Fig. 1 Map of the sampling sites in the lower basin of the Iguape River in the Vale do Ribeira and the sampling site in the Rio Douro in the Ecological Park Perequê Environ Monit Assess (2017) 189: 245 Page 3 of 8 245 sediment sampling site was selected as reference site or non-lethal endpoint studies designed to be protective from the Rio de Ouro (Cubatão, São Paulo) in the of sensitive species (Pluta 2006;Hübneretal.2009). Ecological Park of Perequê (EPP; 23° 50′ 29″ S, 46° C −C 24′ 57″ W). ERF ¼ i SQV C Sediment samples were dried at 60 °C, homogenized SQV in mills and then analyzed for the total organic carbon A cluster analysis (Ward’s method) was applied to (TOC), nitrogen (N), and sulfur (S) by using an elemen- the set original set of variables of sediment characteri- tal analyzer model Vario MACRO Cube. The pseudo- zation (textural distribution, N, S, H, organic matter– total digestion of sediments was performed following OM, total organic content–TOC), the total metal con- the International Organization for Standardization (ISO) centrations, the environmental risk factors (ERF) calcu- standard procedure 11466 (1995). The chemical lated for toxic elements (standardized as the percentage partitioning of metals in sediment was studied by the of deviation) and the concentrations of metal(loid)s in modified Bureau Community of Reference (BCR) se- mobile (M) and residual form (R). According to Mooi quential extraction procedure. An initial step, performed and Sarstedt (2011), cluster analyses have no require- with Milli-Q water as reagent, yielded the most soluble ments of minimum size samples and, thus, it could be fraction (F0); acetic acid was employed as exchangeable used in our study. Statistical analyses were performed fraction and bound to carbonates (F1); the reducible with the aid of the statistical software PAST 1.34 for fraction (F2) bound to the Mn-Fe oxides was extracted Windows (Hammer et al. 2001). with hydroxylammonium chloride; the oxidizable (F3) considered as the fraction bound to organic matter and sulfides was determined with peroxide and ammonium Results and discussion acetate; and the last step with aqua regia digestion, yielded the residual fraction (F4). The sediment diges- Table 1 shows the sediment characterization of the sed- tion procedure and analytical procedures are detailed in iment samples and the total metal concentrations in the Bonnail et al. (2016). The trace metal analysis of major collected sediments from the lower basin of the RIR and and trace elements of solutions took place by means of the Ecological Park Perequê (EPP). Sandy sediments an Agilent Technologies 7700 Series inductively were predominant in SB (98%) and EPP (99%) with coupled plasma mass spectrometer (ICP-MS) and an lower concentration of organic matter (1.40 and 0.60%, Iris Intrepid Model atomic emission spectroscopy respectively). In contrast, the station REG displayed (ICP-AES) by the certified SC-ICYT. To demonstrate greater percentage of fines (14%) and greater organic the reproducibility of the results, the analysis sequences matter (1.60%). The TOC was slightly higher in the RIR consisted of calibration standards, standard solutions than in EPP. analyzed as an unknown (quality control solutions), Table 1 also shows the results of the calculated ERF method blanks, and the certified reference material for the studied area and all the elements. Positive values BCR-701 for sediment-extractable trace elements. Fur- of ERF indicate about adverse effects associated with thermore, an internal check was performed on the se- the metal (Riba et al. 2002b). However, no positive quential extraction by comparing the total amount of value was obtained in the current study which is pointing elements extracted by different reagents during the se- any risk associated with the metal concentrations in the quential extraction procedure with the results of the sediment SB, REG, and EPP. Nevertheless, it is possible to pseudo-total digestion: [(CF0 + CF1 + CF2+ CF3 + CF4)/ rank the elements according to the ERF values obtained CPseudototal digestion] × 100. and associated with the element enrichment in each station: The ecological risk factor (ERF) was calculated as : > > > > > > > > outline in Riba et al.