- Email: [email protected]
Speciation of butyltin derivatives in surface sediments of three southern Brazilian harbors
Journal of Hazardous Materials 181 (2010) 851–856
Contents lists available at ScienceDirect
Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat
Speciation of butyltin derivatives in surface sediments of three southern Brazilian harbors Cristiane Rossi de Oliveira a,∗ , DayanaMoscardi dos Santos b , Luiz Augusto dos Santos Madureira a , Mary Rosa Rodrigues de Marchi c a b c
Laboratory of Environmental Chemistry and Organic Geochemistry, Chemistry Department, UFSC, Florianópolis, Santa Catarina 88040-900, Brazil Chemical and Geological Oceanography Department, Oceanographic Institute, University of São Paulo, São Paulo, SP 05508-900, Brazil Analytical Chemistry Department, Institute of Chemistry, São Paulo State University, P.O. Box 355, Araraquara, SP 14800-900, Brazil
a r t i c l e
i n f o
Article history: Received 9 November 2009 Received in revised form 19 May 2010 Accepted 19 May 2010 Available online 26 May 2010 Keywords: Butyltins Sediments Harbors Santa Catarina
a b s t r a c t For the first time, organotin compounds were determined in surface sediment samples collected from São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors, located in Santa Catarina State, Brazil. Butyltins (BTs) were determined by gas chromatography with a pulsed flame photometric detector (GC-PFPD) after being modified using the Grignard derivatization method. The concentrations of BTs derivatives ranged from n.d. to 1136.6 ng (Sn) g−1 of dry weight (dw) sediment for tributyltin (TBT), n.d. to 394.4 ng (Sn) g−1 dw for dibutyltin (DBT) and n.d. to 312.2 ng (Sn) g−1 dw for monobutyltin (MBT). The highest concentration of total BTs was found at the Itajaí-Ac¸u River dockyard, indicating intense inputs of antifouling paints to the environment. The relative difference in the BTs levels is a particular characteristic of sediments from harbors and may be related to the shipyards and the boat traffic which still use TBT-based antifouling paints. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Tin is one of the most important metals necessary for humans and animals to maintain life functions. Its toxicity toward live organisms is low, however, the organic compounds of tin are poisonous [1]. Organotin compounds (OTCs) are widely used as biocides in agriculture and as catalysts and plastic (PCV) stabilizers in industry. However, the main input of OTCs as butyltin derivatives (BTs) to the sea originates from antifouling paints [2] that are used to protect ship hulls from fouling organisms. These compounds have been used in marine antifouling paints since the mid-1960s and the application of antifouling systems based on organotins allowed the shipping industry to reduce the maintenance and fuel costs and to protect the hull effectively. Due to their hydrophobic behavior in aquatic system, these contaminants are usually found in high levels in the sediment matrix [3]. For this reason, these compounds can be reduced to less toxic forms or transported to non-contaminated sites, depending on hydrodynamic processes in the area [4,5]. In this matrix, OTCs can be bioavailable to the aquatic life and also the sediment may act as a sink or source of these contaminants [6]. Paints based on tributyltin (TBT), one of
∗ Corresponding author. Tel.: +55 48 3721 9949. E-mail addresses: [email protected], cris [email protected] (C.R. de Oliveira). 0304-3894/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2010.05.091
the most toxic compounds used as an active component, received a worldwide commercial prohibition in January 2003, with a total ban in January 2008 [7,8], established by the International Maritime Organization (IMO). However, in countries where monitoring and inspectionare are not effective this paint can still be found. For sediments, critical limits are not yet defined in Brazilian laws [9]. Organotin compounds in the environment have generated great concern and interest due to their highly toxic effects on non-target marine organisms [10,11]. The main characteristic of the sublethal effects of TBT is the hormonal dysfunction in gastropods, leading the imposex [12,13]. This has been observed in many areas where OTCs contamination is present [9,14,15]. The analytical methods currently used for the determination of OTCs are based on chromatographic separation coupled to various detection techniques [16–20]. Prior to gas chromatographic separation, the organometallic species must be either sufficiently volatile or, in the case of ionic organometallic species, rendered volatile by derivatization. Coastal zones are important considering not only the ecological but also the economical point of view. The three harbors, São Francisco do Sul, Itajaí-Navegantes and Imbituba, which are the focus of this study, are located in different regions of Santa Catarina State, one of the three states in southern Brazil. Studies on the environmental aspects of harbors are important since these areas are recipients of toxic chemical inputs from a wide variety of pollution sources which can affect marine coastal ecosystems
852
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Table 1 Geographic and relevant features of the 17 sediment samples. Sample Bab1 Bab2 Bab3 Bab4 Bab5 Imb1 Imb2 Imb3 Imb4 Ita1 Ita2 Ita3 Ita4 Ita5 Ita6 Ita7 Ita8 a b
Location ◦
◦
48 38 127 WO/26 14 247 S 48◦ 38 317 WO/26◦ 14 101 S 48◦ 37 322 WO/26◦ 13 565 S 48◦ 39 803 WO/26◦ 13 287 S 48◦ 39 948 WO/26◦ 13 355 S 48◦ 39 376 WO/28◦ 13 454 S 48◦ 39 121 WO/28◦ 13 639 S 48◦ 39 106 WO/28◦ 13 847 S 48◦ 39 365 WO/28◦ 13 654 S 48◦ 37 880 WO/26◦ 54 896 S 48◦ 39 263 WO/26◦ 54 119 S 48◦ 39 640 WO/26◦ 53 893 S 48◦ 40 153 WO/26◦ 53 884 S 48◦ 40 229 WO/26◦ 53 516 S 48◦ 39 960 WO/26◦ 53 043 S 48◦ 40 950 WO/26◦ 53 270 S 48◦ 41 532 WO/26◦ 52 777 S
Depth (m)
DOa (mg L−1 )
Salinityb (‰)
10.0 14.0 2.0 3.0 3.0 9.0 13.0 12.0 10.0 9.0 5.0 11.0 10.0 4.0 5.0 5.0 5.0
8.0 8.2 7.8 8.3 8.3 9.0 9.1 8.3 8.2 2.2 3.7 1.8 2.3 2.1 2.1 1.8 1.8
26 28 25 22 20 40 22 18 25 25 22 19 11 11 11 10 12
Concentrations measured at the interface water–sediment. Pore-water salinity.
following sediment dredging, seawater diffusion or advective sediment transport. Some studies evaluating the impact of organotin compounds on Brazilian coastal environments have been published [9,21,22]. However, this is the first report on sediments from harbors in Santa Catarina State. Regarding this absence of data, the present study aims to assess the concentration, speciation and spatial variations of BTs in surface sediment samples and evaluate possible input “hotspots”. The determination of phenyltin derivatives, which are also toxic, was not included in this study.
96%, tetrabutyltin (TeBT, as the internal standard) 96%, tripropyltin chloride (TPrT) 98% (used as the surrogate), neutral aluminum oxide and Grignard reagent (2 mol/L pentylmagnesium bromide in diethyl ether) were purchased from Sigma–Aldrich (Milwaukee, WI, USA). Acetic acid, sulfuric acid, sodium hydroxide, and anhydrous sodium sulfate were purchased from JT Baker (Xalostoc, Mexico). Hexane and toluene were acquired from Mallinckrodt (Xalostoc, Mexico). Ammonium pyrrolidinedithiocarbamate (98% APDC) was purchased from Fluka (St. Gallen, Switzerland).
2. Experimental
2.3.2. Total organic carbon determination and granulometric analysis Samples were acidified with 10% solution of HCl overnight to remove carbonates, rinsed with distilled water and dried before analysis for the total organic carbon (TOC) using an Elementary Analyzer CHNS CARLO ERBA – EA1110. Grain size fractions were measured as percent of fine sand, silt and clay using the procedure described by Suguio [25].
2.1. Study area São Francisco do Sul Harbor is located on the northern coast of Santa Catarina State, in the town of São Francisco do Sul, in the Babitonga Bay. This bay shelters the last extensive South American mangrove, being the most important estuarine region of Santa Catarina State [23]. Imbituba Harbor is located on the southern coast, on an open inlet in the town of Imbituba. The region is famous for the presence of the Southern Right Whale from July to November. Itajaí and Navegantes Harbors are located in their homonym cities on the Itajaí-Ac¸u River mouth waterfront. This estuary receives wastewaters and untreated industrial effluents from several towns located in the Itajaí Valley [24]. The vessel traffic registered at each harbor in 2008 follows the increasing order: Imbituba, São Francisco do Sul and Itajaí-Navegantes with 166, 811 and 1015 ships, respectively. 2.2. Sample collection Surface sediment samples (0–10 cm deep) were collected from the São Francisco harbor in October 2007, from Imbituba harbor in April 2008, and from Itajaí-Ac¸u River Mouth in July 2008 (Fig. 1). Sediments were sampled in triplicate at each location using a Van Veen grab and stored at 4 ◦ C during transport to the laboratory. Some data and selected chemical characteristics of the 17 studied samples are shown in Table 1. For each station, individual samples were mixed, homogenized, freeze-dried and sieved (<125 m) before analysis. 2.3. Analytical methods 2.3.1. Reagents BTs standards monobutyltin trichloride (MBTCl3 ) 95%, dibutyltin dichloride (DBTCl2 ) 96%, tributyltin chloride (TBTCl3 )
2.3.3. BTs extraction and analysis BTs were extracted from surface sediment following the method proposed by Godoi et al. [21]. To 2 g of lyophilized sediment, in a test tube, the surrogate (50 L of TPrT, 300 ng g−1 ) was added. BTs were extracted with 10 mL of toluene and 4 mL of acetic acid (vortex 1 min, ultrasonic bath 5 min, centrifuged for 5 min at 2000 rpm). This procedure was repeated three times, and the extracts were transferred to a separation funnel. To the combined extracts, 10 mL of APDC (0.1% in ultrapure water) was added to improve the extraction. The organic phase was then transferred to pear-shaped flasks, dried with anhydrous sodium sulfate, and subsequently concentrated by rotary evaporation at 40–50 ◦ C down to 2 mL. For the derivation, 3 mL of Grignard reagent was added to 2 mL of the concentrated extract. The reaction was stopped after 20 min by adding 20 mL of ultrapure water under ice cooling. Following the solubilization of the white precipitate with a few drops of sulfuric acid, the solution was transferred to a separation funnel and the aqueous phase was discarded. The organic phase was then re-concentrated to 2 mL, dried with sodium sulfate, and passed through an aluminum oxide column for cleanup with hexane as the eluent. Final extracts were concentrated again to 1 mL under gentle N2 flux and TeBT corresponding to 1000 ng g−1 was added as the internal standard. Extracts were analyzed by gas chromatography: Varian 3800 (Walnut Creek, USA) equipped with a pulsed flame photometric detector (PFPD), using a tin filter (390 nm) and a VF5 column
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
853
Fig. 1. Location of the 17 sampling sites for superficial sediments near the three harbors of Santa Catarina State.
(5% phenyl-methylpolysiloxane, Varian, USA) with the temperature program: 130 ◦ C (1 min), 130–280 ◦ C (10 ◦ C min−1 ), 280 ◦ C (4 min); injection mode: splitless for 1 min; injected volume: 2 L; detector temperature: 300 ◦ C; injector temperature: 250 ◦ C; and carrier gas He at a flow rate of 1.7 mL min−1 . The possible interferences in the analysis of BTs were reduced with the cleanup step. Due to the selective detector employed (PFPD), with a tin filter, it is possible to eliminate sulfurous derivative compounds which appear when less selective detectors are used.
according to the Hubber test [28]. The first value outside the linear interval was considered as the detection limit, and the first value inside this interval was considered as the quantification limit. The LOD and LOQ (ng (Sn) mL−1 ) values obtained were, respectively, 7 and 13 for TBT, 16 and 25 for DBT, and 25 and 33 for MBT.
2.3.4. Quality control The quality control for the BTs analysis was based on procedural blanks, spiked samples, TeBT as the internal standard, and TPrT as the surrogate for recovery evaluation. The accuracy and precision of the method were checked using PACS-2 marine sediment reference material (National Research Council of Canada, Ottawa, Canada), and the results were in good agreement with the certified values (Table 2). The results were in accordance with analytical validation recommendations [26,27], i.e., recovery between 70% and 120% and RSD (relative standard deviation) below 20%. Calibration was obtained by the internal standard method. A set of five standards containing 80–1000 ng mL−1 of MBT, 100–1200 ng mL−1 of DBT, 20–800 ng mL−1 of TBT, 80–1000 ng mL−1 of TPrT and 1000 ng mL−1 of TeBT were employed. The limits of detection (LOD) and quantification (LOQ) of the analytical system were obtained by a linearity curve
3. Results and discussion
2.4. Cluster analysis Statistica version 6.0 from Statsoft (2007) was used in the current study for the calculations of the cluster analysis (CA).
3.1. Granulometry and total organic carbon Total organic carbon (TOC) at the sediment–water interface and the sediment grain size distributions for all locations are given in Table 3. Variations in the sand, silt and clay compositions are greatly dependent on the river transport of fine particles. In the Itajaí River mouth region, it can be seen that all locations showed very high contents of fine particles (56.9–85.1% of silt), which are brought by the Itajaí-Ac¸u River. The variation in TOC values did not show a simple correlation with grain size distribution. TOC values remained almost unaltered from station Ita3 to Ita7 (1.45–1.79 mmol g−1 ), but were close to 1.00 mmol g−1 at the Ita1 and Ita2 locations. The maximum TOC concentration (1.79 mmol g−1 ) was found at station Ita7, which is a Itajaí-Ac¸u River sample and the location with the
854
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Table 2 Concentration of butyltins in the reference material and the recovered values (mean and standard deviation; n = 3) expressed in g (Sn) g−1 dw. BTs
CRM-PACS-2
Result (recovery)
MBT DBT TBT
(0.6)a 1.047 ± 0.064 0.890 ± 0.105
0.620 ± 0.130 1.030 ± 0.265 0.986 ± 0.057
BTs: butyltin derivatives; MBT: monobutyltin; DBT: dibutyltin; TBT: tributyltin; CRM-PACS-2: marine sediment reference material (National Research Council of Canada, Ottawa, Canada). a Single value with no standard deviation.
highest percentage of sand (33.3%). As in the Itajaí-Ac¸u River sediments, no clear correlations were observed between the percentage of fine particles and the TOC contents of the sediments from the two other regions. The degree of sediment sorting at the sampling points, due to the multiple and intense processes of mechanical mixing, is most likely attributable to dredging and the expansion of the specific port canals. Several studies have previously indicated that fine-grained sediments are more susceptible to accumulation and preservation of organic matter [29,30]. 3.2. Speciation and concentration of organotin compounds in the sediment samples BTs contents in the sediment samples from Santa Catarina harbors vary widely and are dependent on the location. Concentrations of the different BTs derivatives for the 17 stations are given in Table 3 and an example of a chromatogram is given in Fig. 2. In marine environments, TBT undergoes microbial degradation and photodegradation, being decomposed to DBT (dibutyltin) and MBT (monobutyltin), which are less toxic products [1,31]. BTs were quantified and the range of concentration values (ng (Sn) g−1 dw) were n.d. to 1136.6 for TBT, n.d. to 394.4 for DBT and n.d. to 312.2 for MBT. For stations Bab3, Bab4 and Imb4 concentration values were below the LOQ. It can be observed from Table 3 that the speciation and concentration of BTs increased toward the stations close to the harbors. The highest contents of contaminants are found in the samples collected from the harbor dockyards (Bab1, Imb3, Ita3, Ita4 and Ita5) and marinas (Ita2, Ita6 and Ita8). The relative differences between BTs levels might be due to particular characteristics of the harbors and sampling sites. In addition, the intense traffic of boats and other vessels, which still use TBT-based antifouling paints, and industrial activities, such as plastics manufacturers which may use TBT as a stabilizer, are present in the Itajaí Valley, and could be responsible for the different contaminant levels found.
Fig. 2. Chromatogram obtained for sample Imb3 by GC-PFPD analysis. Compounds identified: tripropyltin (TPrT), tetrabutyltin (TeBT), tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT).
The level of contamination of the three regions studied, São Francisco do Sul, Itajaí-Navegantes and Imbituba, can be estimated using the pollution classification index proposed by Waite et al. [32]. The investigated locations may be ranked as follows: Imb3, Ita2, Ita3, Ita4, Ita6 and Ita8 as highly polluted (300–1000 ng (Sn) g−1 TBT), Bab1 and Bab2 as moderately polluted (60–200 ng (Sn) g−1 TBT) and Bab5 and Ita7 as slightly polluted (10–50 ng (Sn) g−1 TBT). According to this classification, sediments containing concentrations higher than 1000 ng (Sn) g−1 TBT (station Ita5) are likely to contain paint particles. According to the Australian sediment quality guidelines for TBT, the concentrations established as low and high trigger values are 5 and 70 ng (Sn) g−1 [33]. This classification places most of the sediment samples from these Santa Catarina harbors above the safety range and thus they represent a risk to the benthic organisms. The Sediment Quality Guidelines (SQGs) proposed by Dutch RIKZ (National Institute for Coastal and Marine Management) were also used as reference values to assess the impact of TBT levels found in Santa Catarina harbors. The maximum permissible concentrations and the negligible concentrations are 0.7 and 0.007 ng
Table 3 Bulk parameters and butyltin average concentrations (n = 3) in the sediments sampled at the Santa Catarina harbor regions. Station
Sand (%)
Silt (%)
Clay (%)
TOC (mmol g−1 )
TBT (ng (Sn) g−1 dw)
DBT (ng (Sn) g−1 dw)
MBT (ng (Sn) g−1 dw)
BTs
TBT/TOC
BDI
Bab1 Bab2 Bab3 Bab4 Bab5 Imb1 Imb2 Imb3 Imb4 Ita1 Ita2 Ita3 Ita4 Ita5 Ita6 Ita7 Ita8
26.9 49.5 65.2 35.0 68.7 82.0 64.6 55.8 52.4 16.6 25.4 17.6 6.3 14.3 1.2 33.3 19.5
70.6 43.2 32.7 60.7 27.2 16.8 28.3 40.0 44.3 56.9 67.3 72.7 76.5 75.4 85.1 59.3 70.6
2.4 7.3 2.1 4.3 4.1 1.1 7.0 4.2 3.3 26.5 7.3 9.7 17.2 10.3 13.7 7.4 10.0
1.74 2.64 1.14 2.04 1.06 0.43 1.05 2.98 1.41 0.89 1.06 1.45 1.46 1.51 1.58 1.79 1.56
125.0 88.5 n.d. n.d. 24.3 n.d. n.d. 428.9 n.d. n.d. 806.4 466.2 578.1 1136.6 857.8 39.1 445.6
394.4 n.d. n.d. n.d. 36.2 68.2 99.6 125.2 n.d. 115.2 n.d. 1.5 n.d. 36.2 32.6 19.8 14.0
312.2 45.4 n.d. n.d. 32.3 181.1 59.3 133.1 n.d. 48.2 n.d. 38.8 n.d. 94.9 106.7 28.6 126.3
831.5 134.0 n.d. n.d. 92.9 249.3 158.9 687.2 n.d. 163.4 806.4 506.5 578.1 1267.7 997.1 87.5 585.9
71.8 33.5 n.d. n.d. 23.0 n.d. n.d. 143.9 n.d. n.d. 760.8 321.5 396.0 752.7 542.9 21.8 285.6
5.7 0.5 n.d. n.d. 2.8 1 1 0.6 n.d. 1 1 0.1 1 0.1 0.2 1.2 0.3
Butyltin degradation index (BDI) = [MBT] + [DBT]/[TBT]; BTs = [TBT] + [DBT] + [MBT]; n.d. = not detectable, below LOD; Rsd below 20%.
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
855
Fig. 3. Mean distribution concentrations of tributyltin, dibutyltin, monobutyltin and total butyltin derivatives from sampling sites in Santa Catarina harbors. Sample locations are indicated in Fig. 1.
(Sn) g−1 dw, respectively, based on a standard sediment having 10% organic matter, or equivalently 5% organic carbon [34]. When normalized to total organic carbon, this corresponds to 0.014 g g−1 TOC and 0.00014 g g−1 TOC, respectively. Concentrations normalized to organic carbon contents are shown in Table 3. On comparing the organic carbon-normalized TBT contents in the sediments of Santa Catarina with the Dutch criteria, these TBT values exceeded the maximum permissible concentration, especially at stations Ita2, Ita3, Ita4, Ita5, Ita6, Ita8 and Imb3 from the Itajaí-Ac¸u River and Imbituba sites. The process of BTs sorption to sediments is fast and involves primarily particulate organic matter constituents that act as sorbents [35]. For this study, no correlation was found between BTs concentrations and the relative organic carbon contents in the sediments. Sedimentary BTs levels described in this study were also compared to those reported in different coastal areas of the southeast of Brazil. Fernandez et al. [22] found in Guanabara Bay values of TBT ranging from 10 to 520.9 ng (Sn) g−1 dw. Values detected along the São Paulo coast varied from 90 to 482 ng (Sn) g−1 dw in Santos Harbor, 224 to 847 ng (Sn) g−1 dw in Guarujá Marina and 17 to 53 ng (Sn) g−1 dw in the Cananéia region [24]. On the Paranaguá Estuarine complex located in Paraná State, TBT was found in all sediment samples, ranging from 363 to 2796 ng (Sn) g−1 dw [9]. Total BTs contents observed along the Brazilian coast are close to those reported by other authors worldwide [34,36]. Since they are high in areas dedicated to drydocking and marinas, it can be concluded that these activities are expressive sources of organotin contaminants in the local marine environment. Tributyltin degrades quickly in seawater, where it has a residence time of days. On the other hand, in sediments it tends to adsorb onto particles and the degradation processes are considerably slower [37]. A significant degradation of tributyltin to monosubstituted forms has been described by several authors. Generally, high TBT concentrations are found in impacted areas and it is assumed that the environment has been recently contaminated by BTs. However, when the concentration of monosubstituted derivatives found in sediments are higher, the contamination is considered to be historic or, alternatively, the processes of degradation may be faster. The degradation coefficient for OTC was defined by Díez et al. [18] and can be used to estimate the degree of BTs degradation at each location. Butyltin degradation index (BDI) values lower than 1 are indicative of recent input of contaminants and values higher than 1 can express the lack of recent influx. Considering the values for the degradation coefficient obtained (Table 3) and the distribution of butyltin derivatives (Fig. 3), the occurrence of historic contamination or faster degradation kinetics at stations Imb1, Imb2 and Ita1 can be inferred when compared to the other locations studied. At station Ita1, located at the mouth of the ItajaíAc¸u River, and at stations Imb1 and Imb2, located in an open inlet,
Fig. 4. Dendogram of the hierarchical cluster analysis for butyltin derivatives and BDI (butyltin degradation index) in surface sediments collected from harbors along the Santa Catarina coast.
the water column dynamics may also facilitate the sediment advection, associated with shipping traffic, river inputs and tidal effects. Considering the dissolved oxygen values at stations Imb1 and Imb2 (9.0 and 9.1 mg L−1 , respectively) the degradation processes may be faster than at station Ita1, with a lower DO value (2.2 mg L−1 ) and possibly historic contamination. Station Bab1 is an enclosed vessel dock, where dredging activities are periodic. Sediment mixing and uptake probably explain the higher proportion of DBT and MBT found at this site. In contrast, for station Bab5 the high BDI index can be attributed to historic contamination. This location has been used for the discarding of dredging residues. At stations Ita2 and Ita4 only TBT was found. These are located in the dock harbor and might be receiving and absorbing TBT antifouling paint recently released. This supposition might be attributed given the values found at the other sites of the Itajaí Valley close to these stations. Stations Ita3, Ita5, Ita6 and Ita8 also present lower values of DBI with expressive TBT concentrations. Station Ita7 is located at the mouth of Itajaí-Mirim River. The discharge of water and dissolution of pollutants might explain the low values found at this site. 3.3. Cluster analysis (CA) Hierarchical cluster analysis (HCA), the CA method most frequently applied to environmental analysis, groups samples according to their similarities. HCA is a powerful tool for analyzing data sets for expected or unexpected clusters including the presence of outliers. In HCA, the most similar points are grouped forming one cluster and the process is repeated until all points belong to one cluster. This analysis examines distances between samples and data sets. In the current study, the single linkage HCA method was applied to the data for the surface sediments, using Euclidian distances. The data matrix examined includes the concentrations of butyltin derivatives and BDI in relation to locations in the study area. The aim of the HCA was to consider the highest number of variables which can characterize the impact of BTs. The result is shown in a dendogram (Fig. 4). A total number of four groups were observed. The dendogram suggests that the groupings were primarily correlated to TBT contents. The association of Imb1, Imb2 and Ita1 can be classified as historic contamination, since only DBT and MBT were found. Locations Bab2, Bab5 and Ita7 are gathered together in the same group due to lower TBT contents in comparison to the other stations; and station Bab2 showing lower BDI values. Stations
856
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Imb2, Ita3, Ita3, Ita4, Ita5, Ita6 and Ita8 form the biggest group. The similarity of the samples in this group is the high concentrations of TBT in contrast to DBT and MBT. In addition, the low BDI values found in this group represent recent input of contaminants. Station Bab1 shows a high BDI value. However, the TBT content is also high when compared to the stations with historic inputs. For this reason, it does not show strong similarity with the other locations. 4. Conclusions For the first time the sediment contamination levels at São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors were assessed using GC-PFPD. This study revealed that despite the total ban on the use of TBT in January 2008 these harbor regions may act as “hotspots” of pollution. This species has been used as a biocide in marine antifouling paints. BTs contents vary widely and are dependent on the station location and the individual characteristics of each harbor. The magnitude of the contamination was consistent with values reported for sediments in commercial harbors and marinas worldwide. Substantial amounts of the degradation products DBT and MBT were determined in this study, indicating that natural attenuation is contributing to sediment remediation. Because harbor regions are of crucial economical interest, it is clear that a larger spatio-temporal organotin monitoring program needs to be set up, in order to continuously evaluate the level of BTs contamination in the Santa Catarina coastal area. Acknowledgments Thanks are due to the Rescue & Save Brigade of Itajaí for helping us to collect samples at the Itajaí-Ac¸u River. Scholarship for C. R. Oliveira was provided by CAPES. Financial support was provided by Petrobras and FAPESC. References [1] M. Hoch, Organotin compounds in the environmental–an overview, Appl. Geochem. 16 (2001) 719–743. [2] Y. Morcillo, C. Porte, Evidence of endocrine disruption in clams Ruditapes decussata-transplanted to a tributyltin-polluted environment, Environ. Pollut. 107 (2000) 47–52. [3] G.M. Gadd, Microbial interactions with tributyltin compounds: detoxification, accumulation, and environmental fate, Sci. Total Environ. 258 (2000) 119–127. [4] H.L. Tan, B. Clarcke, D. Lockington, Analysis of Organotin (TBT) in the Environment and Analytical Methods, Tese, CHEE 4006/7, The University of Queensland, Australia, 2004. [5] C.J. Buggy, J.M. Tobin, Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland, Environ. Pollut. 143 (2006) 294–303. [6] D. Cao, G. Jiang, Q. Zhou, R. Yang, Organotin pollution in China: an overview of the current state and potential risk, Environ. Manage. 90 (2009) S16–S24. [7] M.A. Champ, Economic and environmental impacts on ports and harbors from the convention to ban harmful marine anti-fouling systems, Mar. Pollut. Bull. 46 (2003) 935–940. [8] M.A. Fernandez, F.M. Pinheiro, New approaches for monitoring the marine environment: the case of antifouling paints, Int. J. Environ. Health 1 (2007) 427–448. [9] D.M. Santos, I.P. Araújo, E.C. Machado, M.A.S. Carvalho-Filho, M.A. Fernandez, M.R.R. Marchi, A.F. Godoi, Organotin compounds in the Paranaguá Estuarine Complex, Paraná, Brazil: evaluation of biological effects, surface sediment, and suspended particulate matter, Mar. Pollut. Bull. (2009), doi:10.1016/j.marpolbul.2009.09.004. [10] L.W. Hall, A.E. Pinkney, Acute and sublethal effects of organotin compounds on aquatic biota: an interpretative literature evaluation, Crit. Rev. Toxicol. 14 (1985) 159–167. [11] M.C. Lau, K.M. Chan, K.M.Y. Leung, T.G. Luan, M.S. Yang, J.W. Qiu, Acute and chronic toxicities of tributyltin to various life stages of the marine polychaete Hydroideselegans, Chemosphere 69 (2007) 135–144.
[12] T. Horiguchi, H. Shiraishi, M. Shimizu, M. Morita, Effects of triphenyltin chloride and five other organotin compounds on the development of imposex in the rock shell, Thais Clavigera, Environ. Pollut. 95 (1) (1997) 85–91. [13] M.H. Depledge, Z. Billinghurst, Ecological significance of endocrine disruption in marine invertebrates, Mar. Pollut. Bull. 39 (1–12) (1999) 32–38. [14] P. Mathiessen, P.E. Gibbs, Critical appraisal of the evidence for tributyltinmediated endocrine disruption in molluscs, Environ. Toxicol. Chem. 17 (1998) 37–43. [15] A.M. Limaverde, A.L.R. Wagener, M.A. Fernandez, A.L. Scofield, R. Coutinho, Stramonitahaemastoma as a bioindicator for organotin contamination in coastal environments, Mar. Environ. Res. 64 (2007) 384–398. [16] E. Millán, J. Pawliszyn, Determination of butyltin species in water and sediment by solid-phase microextraction-gas chromatography-flame ionization detection, J. Chromatogr. A. 873 (2000) 63–71. [17] S. Aguerre, G. Lespes, V. Desauziers, M. Potin-Gautier, Speciation of organotins in environmental samples by SPME-GC: comparison of four specific detectors: FPD, PFPD, MIP-AES and ICP-MS, J. Anal. Atom. Spectrom. 16 (2001) 263– 269. [18] S. Díez, M. Ábalos, J.M. Bayona, Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation, Water Res. 36 (2002) 905–918. [19] S. Tsunoi, T. Matoba, H. Shioji, L.T.H. Giang, H. Harino, M. Tanaka, Analysis of organotin compounds by Grignard derivatisation and gas chromatography–ion trap tandem mass spectrometry, J. Chromatogr. A 962 (2002) 197–206. [20] C. Devos, M. Vliegen, B. Willaert, F. David, L. Moens, P. Sandra, Automated headspace-solid-phase micro-extraction–retention time locked-isotope dilution gas chromatography–mass spectrometry for the analysis of organotin compounds in water and sediment samples, J. Chromatogr. A 1079 (2005) 408–414. [21] A.F.L. Godoi, R.C. Montone, M. Santiago-Silva, Determination of butyltin compounds in surface sediments from the São Paulo State coast (Brazil) by gas chromatography-pulsed flame photometric detection, J. Chromatogr. A 985 (2003) 205–210. [22] M.A. Fernandez, A.L.R. Wagener, A.M. Limaverde, A.L. Scofield, F.M. Pinheiro, E. Rodrigues, Imposex and surface sediment speciation: a combined approach to evaluate Organotin contamination in Guanabara Bay, Rio de Janeiro, Brazil, Mar. Environ. Res. 59 (2005) 435–452. [23] M.J. Cremer, P.R.D. Morales, T.M.N. Oliveira, Diagnóstico Ambiental da Baía da Babitonga Joinville, SC, UNIVILLE Press, Joinville, Brazil, 2006. [24] J.P. Filho, L.C. Spillere, C.A.F. Schettini, Dinâmica de nutrientes na região portuária do estuário do Rio Itajaí-Ac¸u, SC, Atlântica (Rio Grande) 25 (1) (2003) 11–20. [25] K. Suguio, Introduc¸ão à Sedimentologia, Edgard Buckler, EDUSP, São Paulo, 1973. [26] EURACHEM-The Fitness for Purpose of Analytical Methods, A laboratory guide to method validation and related topics, LGC (Teddington) Ltd., London, 1998, p. 75. [27] IUPAC (International Union of Pure and Applied Chemistry), Analytical, applied, clinical, inorganic, and physical chemistry divisions interdivisional working party for harmonization of quality assurance schemes for analytical laboratories, Pure Appl. Chem. 74 (2002) 835–855. [28] M. Ribani, C.B.G. Bottoli, C.H. Collins, I.C.S.F. Jardim, L.F.C. Melo, Validac¸ão em métodos cromatográficos e eletroforéticos, Quim. Nova 27 (2004) 771–780. [29] K.A. Burns, P.F. Greenwood, R.E. Summons, G.J. Brunskill, Vertical fluxes of hydrocarbons on the Northwest Shelf of Australia as estimated by a sediment trap study, Org. Geochem. 32 (10) (2001) 1241–1255. [30] L. Mater, M.R. Alexandre, F.A. Hanzel, L.A.S. Madureira, Assessment of lipid compounds and phosphorus in mangrove sediments of Santa Catarina Island, SC, Brazil, J. Braz. Chem. Soc. 15 (2004) 1–10. [31] C. Marcic, I.L. Hecho, L. Denaix, G. Lespes, TBT and TPhT persistence in a sludged soil, Chemosphere 65 (2006) 2322–2332. [32] M.E. Waite, M.J. Waldock, J.E. Thain, D.J. Smith, S.M. Milton, Reductions in TBT concentrations in UK estuaries following legislation in 1986 and 1987, Mar. Environ. Res. 32 (1991) 89–111. [33] ANZECC/ARMCANZ, Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council/Agricuture and Resource Management Council of Australian and New Zealand, Canberra, 2000. [34] S. Díez, J.M. Bayona, Butyltin occurrence and risk assessment in the sediments of the Iberian Peninsula, J. Environ. Manage. 90 (2009) S25–S30. [35] M. Berg, C.G. Arnold, S.R. Muller, J. Muhlemann, R.P. Schwarzenbach, Sorption and desorption behavior of organotin compounds in sediment-pore water systems, Environ. Sci. Technol. 35 (2001) 3151–3157. [36] N.B. Bhosle, A. Garg, R. Harji, S. Jadhav, S.S. Sawant, V. Krishnamurthy, C. Anil, Butyltins in the sediments of Kochi and Mumbai harbours, west coast of India, Environ. Int. 32 (2006) 252–258. [37] P.M. Sarradin, Y. Lapaquellerie, A. Astruc, C. Latouche, M. Astruc, Long term behaviour and degradation kinetics of tributyltin in a marina sediment, Sci. Total Environ. 170 (1995) 59–70.
Contents lists available at ScienceDirect
Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat
Speciation of butyltin derivatives in surface sediments of three southern Brazilian harbors Cristiane Rossi de Oliveira a,∗ , DayanaMoscardi dos Santos b , Luiz Augusto dos Santos Madureira a , Mary Rosa Rodrigues de Marchi c a b c
Laboratory of Environmental Chemistry and Organic Geochemistry, Chemistry Department, UFSC, Florianópolis, Santa Catarina 88040-900, Brazil Chemical and Geological Oceanography Department, Oceanographic Institute, University of São Paulo, São Paulo, SP 05508-900, Brazil Analytical Chemistry Department, Institute of Chemistry, São Paulo State University, P.O. Box 355, Araraquara, SP 14800-900, Brazil
a r t i c l e
i n f o
Article history: Received 9 November 2009 Received in revised form 19 May 2010 Accepted 19 May 2010 Available online 26 May 2010 Keywords: Butyltins Sediments Harbors Santa Catarina
a b s t r a c t For the first time, organotin compounds were determined in surface sediment samples collected from São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors, located in Santa Catarina State, Brazil. Butyltins (BTs) were determined by gas chromatography with a pulsed flame photometric detector (GC-PFPD) after being modified using the Grignard derivatization method. The concentrations of BTs derivatives ranged from n.d. to 1136.6 ng (Sn) g−1 of dry weight (dw) sediment for tributyltin (TBT), n.d. to 394.4 ng (Sn) g−1 dw for dibutyltin (DBT) and n.d. to 312.2 ng (Sn) g−1 dw for monobutyltin (MBT). The highest concentration of total BTs was found at the Itajaí-Ac¸u River dockyard, indicating intense inputs of antifouling paints to the environment. The relative difference in the BTs levels is a particular characteristic of sediments from harbors and may be related to the shipyards and the boat traffic which still use TBT-based antifouling paints. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Tin is one of the most important metals necessary for humans and animals to maintain life functions. Its toxicity toward live organisms is low, however, the organic compounds of tin are poisonous [1]. Organotin compounds (OTCs) are widely used as biocides in agriculture and as catalysts and plastic (PCV) stabilizers in industry. However, the main input of OTCs as butyltin derivatives (BTs) to the sea originates from antifouling paints [2] that are used to protect ship hulls from fouling organisms. These compounds have been used in marine antifouling paints since the mid-1960s and the application of antifouling systems based on organotins allowed the shipping industry to reduce the maintenance and fuel costs and to protect the hull effectively. Due to their hydrophobic behavior in aquatic system, these contaminants are usually found in high levels in the sediment matrix [3]. For this reason, these compounds can be reduced to less toxic forms or transported to non-contaminated sites, depending on hydrodynamic processes in the area [4,5]. In this matrix, OTCs can be bioavailable to the aquatic life and also the sediment may act as a sink or source of these contaminants [6]. Paints based on tributyltin (TBT), one of
∗ Corresponding author. Tel.: +55 48 3721 9949. E-mail addresses: [email protected], cris [email protected] (C.R. de Oliveira). 0304-3894/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2010.05.091
the most toxic compounds used as an active component, received a worldwide commercial prohibition in January 2003, with a total ban in January 2008 [7,8], established by the International Maritime Organization (IMO). However, in countries where monitoring and inspectionare are not effective this paint can still be found. For sediments, critical limits are not yet defined in Brazilian laws [9]. Organotin compounds in the environment have generated great concern and interest due to their highly toxic effects on non-target marine organisms [10,11]. The main characteristic of the sublethal effects of TBT is the hormonal dysfunction in gastropods, leading the imposex [12,13]. This has been observed in many areas where OTCs contamination is present [9,14,15]. The analytical methods currently used for the determination of OTCs are based on chromatographic separation coupled to various detection techniques [16–20]. Prior to gas chromatographic separation, the organometallic species must be either sufficiently volatile or, in the case of ionic organometallic species, rendered volatile by derivatization. Coastal zones are important considering not only the ecological but also the economical point of view. The three harbors, São Francisco do Sul, Itajaí-Navegantes and Imbituba, which are the focus of this study, are located in different regions of Santa Catarina State, one of the three states in southern Brazil. Studies on the environmental aspects of harbors are important since these areas are recipients of toxic chemical inputs from a wide variety of pollution sources which can affect marine coastal ecosystems
852
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Table 1 Geographic and relevant features of the 17 sediment samples. Sample Bab1 Bab2 Bab3 Bab4 Bab5 Imb1 Imb2 Imb3 Imb4 Ita1 Ita2 Ita3 Ita4 Ita5 Ita6 Ita7 Ita8 a b
Location ◦
◦
48 38 127 WO/26 14 247 S 48◦ 38 317 WO/26◦ 14 101 S 48◦ 37 322 WO/26◦ 13 565 S 48◦ 39 803 WO/26◦ 13 287 S 48◦ 39 948 WO/26◦ 13 355 S 48◦ 39 376 WO/28◦ 13 454 S 48◦ 39 121 WO/28◦ 13 639 S 48◦ 39 106 WO/28◦ 13 847 S 48◦ 39 365 WO/28◦ 13 654 S 48◦ 37 880 WO/26◦ 54 896 S 48◦ 39 263 WO/26◦ 54 119 S 48◦ 39 640 WO/26◦ 53 893 S 48◦ 40 153 WO/26◦ 53 884 S 48◦ 40 229 WO/26◦ 53 516 S 48◦ 39 960 WO/26◦ 53 043 S 48◦ 40 950 WO/26◦ 53 270 S 48◦ 41 532 WO/26◦ 52 777 S
Depth (m)
DOa (mg L−1 )
Salinityb (‰)
10.0 14.0 2.0 3.0 3.0 9.0 13.0 12.0 10.0 9.0 5.0 11.0 10.0 4.0 5.0 5.0 5.0
8.0 8.2 7.8 8.3 8.3 9.0 9.1 8.3 8.2 2.2 3.7 1.8 2.3 2.1 2.1 1.8 1.8
26 28 25 22 20 40 22 18 25 25 22 19 11 11 11 10 12
Concentrations measured at the interface water–sediment. Pore-water salinity.
following sediment dredging, seawater diffusion or advective sediment transport. Some studies evaluating the impact of organotin compounds on Brazilian coastal environments have been published [9,21,22]. However, this is the first report on sediments from harbors in Santa Catarina State. Regarding this absence of data, the present study aims to assess the concentration, speciation and spatial variations of BTs in surface sediment samples and evaluate possible input “hotspots”. The determination of phenyltin derivatives, which are also toxic, was not included in this study.
96%, tetrabutyltin (TeBT, as the internal standard) 96%, tripropyltin chloride (TPrT) 98% (used as the surrogate), neutral aluminum oxide and Grignard reagent (2 mol/L pentylmagnesium bromide in diethyl ether) were purchased from Sigma–Aldrich (Milwaukee, WI, USA). Acetic acid, sulfuric acid, sodium hydroxide, and anhydrous sodium sulfate were purchased from JT Baker (Xalostoc, Mexico). Hexane and toluene were acquired from Mallinckrodt (Xalostoc, Mexico). Ammonium pyrrolidinedithiocarbamate (98% APDC) was purchased from Fluka (St. Gallen, Switzerland).
2. Experimental
2.3.2. Total organic carbon determination and granulometric analysis Samples were acidified with 10% solution of HCl overnight to remove carbonates, rinsed with distilled water and dried before analysis for the total organic carbon (TOC) using an Elementary Analyzer CHNS CARLO ERBA – EA1110. Grain size fractions were measured as percent of fine sand, silt and clay using the procedure described by Suguio [25].
2.1. Study area São Francisco do Sul Harbor is located on the northern coast of Santa Catarina State, in the town of São Francisco do Sul, in the Babitonga Bay. This bay shelters the last extensive South American mangrove, being the most important estuarine region of Santa Catarina State [23]. Imbituba Harbor is located on the southern coast, on an open inlet in the town of Imbituba. The region is famous for the presence of the Southern Right Whale from July to November. Itajaí and Navegantes Harbors are located in their homonym cities on the Itajaí-Ac¸u River mouth waterfront. This estuary receives wastewaters and untreated industrial effluents from several towns located in the Itajaí Valley [24]. The vessel traffic registered at each harbor in 2008 follows the increasing order: Imbituba, São Francisco do Sul and Itajaí-Navegantes with 166, 811 and 1015 ships, respectively. 2.2. Sample collection Surface sediment samples (0–10 cm deep) were collected from the São Francisco harbor in October 2007, from Imbituba harbor in April 2008, and from Itajaí-Ac¸u River Mouth in July 2008 (Fig. 1). Sediments were sampled in triplicate at each location using a Van Veen grab and stored at 4 ◦ C during transport to the laboratory. Some data and selected chemical characteristics of the 17 studied samples are shown in Table 1. For each station, individual samples were mixed, homogenized, freeze-dried and sieved (<125 m) before analysis. 2.3. Analytical methods 2.3.1. Reagents BTs standards monobutyltin trichloride (MBTCl3 ) 95%, dibutyltin dichloride (DBTCl2 ) 96%, tributyltin chloride (TBTCl3 )
2.3.3. BTs extraction and analysis BTs were extracted from surface sediment following the method proposed by Godoi et al. [21]. To 2 g of lyophilized sediment, in a test tube, the surrogate (50 L of TPrT, 300 ng g−1 ) was added. BTs were extracted with 10 mL of toluene and 4 mL of acetic acid (vortex 1 min, ultrasonic bath 5 min, centrifuged for 5 min at 2000 rpm). This procedure was repeated three times, and the extracts were transferred to a separation funnel. To the combined extracts, 10 mL of APDC (0.1% in ultrapure water) was added to improve the extraction. The organic phase was then transferred to pear-shaped flasks, dried with anhydrous sodium sulfate, and subsequently concentrated by rotary evaporation at 40–50 ◦ C down to 2 mL. For the derivation, 3 mL of Grignard reagent was added to 2 mL of the concentrated extract. The reaction was stopped after 20 min by adding 20 mL of ultrapure water under ice cooling. Following the solubilization of the white precipitate with a few drops of sulfuric acid, the solution was transferred to a separation funnel and the aqueous phase was discarded. The organic phase was then re-concentrated to 2 mL, dried with sodium sulfate, and passed through an aluminum oxide column for cleanup with hexane as the eluent. Final extracts were concentrated again to 1 mL under gentle N2 flux and TeBT corresponding to 1000 ng g−1 was added as the internal standard. Extracts were analyzed by gas chromatography: Varian 3800 (Walnut Creek, USA) equipped with a pulsed flame photometric detector (PFPD), using a tin filter (390 nm) and a VF5 column
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
853
Fig. 1. Location of the 17 sampling sites for superficial sediments near the three harbors of Santa Catarina State.
(5% phenyl-methylpolysiloxane, Varian, USA) with the temperature program: 130 ◦ C (1 min), 130–280 ◦ C (10 ◦ C min−1 ), 280 ◦ C (4 min); injection mode: splitless for 1 min; injected volume: 2 L; detector temperature: 300 ◦ C; injector temperature: 250 ◦ C; and carrier gas He at a flow rate of 1.7 mL min−1 . The possible interferences in the analysis of BTs were reduced with the cleanup step. Due to the selective detector employed (PFPD), with a tin filter, it is possible to eliminate sulfurous derivative compounds which appear when less selective detectors are used.
according to the Hubber test [28]. The first value outside the linear interval was considered as the detection limit, and the first value inside this interval was considered as the quantification limit. The LOD and LOQ (ng (Sn) mL−1 ) values obtained were, respectively, 7 and 13 for TBT, 16 and 25 for DBT, and 25 and 33 for MBT.
2.3.4. Quality control The quality control for the BTs analysis was based on procedural blanks, spiked samples, TeBT as the internal standard, and TPrT as the surrogate for recovery evaluation. The accuracy and precision of the method were checked using PACS-2 marine sediment reference material (National Research Council of Canada, Ottawa, Canada), and the results were in good agreement with the certified values (Table 2). The results were in accordance with analytical validation recommendations [26,27], i.e., recovery between 70% and 120% and RSD (relative standard deviation) below 20%. Calibration was obtained by the internal standard method. A set of five standards containing 80–1000 ng mL−1 of MBT, 100–1200 ng mL−1 of DBT, 20–800 ng mL−1 of TBT, 80–1000 ng mL−1 of TPrT and 1000 ng mL−1 of TeBT were employed. The limits of detection (LOD) and quantification (LOQ) of the analytical system were obtained by a linearity curve
3. Results and discussion
2.4. Cluster analysis Statistica version 6.0 from Statsoft (2007) was used in the current study for the calculations of the cluster analysis (CA).
3.1. Granulometry and total organic carbon Total organic carbon (TOC) at the sediment–water interface and the sediment grain size distributions for all locations are given in Table 3. Variations in the sand, silt and clay compositions are greatly dependent on the river transport of fine particles. In the Itajaí River mouth region, it can be seen that all locations showed very high contents of fine particles (56.9–85.1% of silt), which are brought by the Itajaí-Ac¸u River. The variation in TOC values did not show a simple correlation with grain size distribution. TOC values remained almost unaltered from station Ita3 to Ita7 (1.45–1.79 mmol g−1 ), but were close to 1.00 mmol g−1 at the Ita1 and Ita2 locations. The maximum TOC concentration (1.79 mmol g−1 ) was found at station Ita7, which is a Itajaí-Ac¸u River sample and the location with the
854
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Table 2 Concentration of butyltins in the reference material and the recovered values (mean and standard deviation; n = 3) expressed in g (Sn) g−1 dw. BTs
CRM-PACS-2
Result (recovery)
MBT DBT TBT
(0.6)a 1.047 ± 0.064 0.890 ± 0.105
0.620 ± 0.130 1.030 ± 0.265 0.986 ± 0.057
BTs: butyltin derivatives; MBT: monobutyltin; DBT: dibutyltin; TBT: tributyltin; CRM-PACS-2: marine sediment reference material (National Research Council of Canada, Ottawa, Canada). a Single value with no standard deviation.
highest percentage of sand (33.3%). As in the Itajaí-Ac¸u River sediments, no clear correlations were observed between the percentage of fine particles and the TOC contents of the sediments from the two other regions. The degree of sediment sorting at the sampling points, due to the multiple and intense processes of mechanical mixing, is most likely attributable to dredging and the expansion of the specific port canals. Several studies have previously indicated that fine-grained sediments are more susceptible to accumulation and preservation of organic matter [29,30]. 3.2. Speciation and concentration of organotin compounds in the sediment samples BTs contents in the sediment samples from Santa Catarina harbors vary widely and are dependent on the location. Concentrations of the different BTs derivatives for the 17 stations are given in Table 3 and an example of a chromatogram is given in Fig. 2. In marine environments, TBT undergoes microbial degradation and photodegradation, being decomposed to DBT (dibutyltin) and MBT (monobutyltin), which are less toxic products [1,31]. BTs were quantified and the range of concentration values (ng (Sn) g−1 dw) were n.d. to 1136.6 for TBT, n.d. to 394.4 for DBT and n.d. to 312.2 for MBT. For stations Bab3, Bab4 and Imb4 concentration values were below the LOQ. It can be observed from Table 3 that the speciation and concentration of BTs increased toward the stations close to the harbors. The highest contents of contaminants are found in the samples collected from the harbor dockyards (Bab1, Imb3, Ita3, Ita4 and Ita5) and marinas (Ita2, Ita6 and Ita8). The relative differences between BTs levels might be due to particular characteristics of the harbors and sampling sites. In addition, the intense traffic of boats and other vessels, which still use TBT-based antifouling paints, and industrial activities, such as plastics manufacturers which may use TBT as a stabilizer, are present in the Itajaí Valley, and could be responsible for the different contaminant levels found.
Fig. 2. Chromatogram obtained for sample Imb3 by GC-PFPD analysis. Compounds identified: tripropyltin (TPrT), tetrabutyltin (TeBT), tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT).
The level of contamination of the three regions studied, São Francisco do Sul, Itajaí-Navegantes and Imbituba, can be estimated using the pollution classification index proposed by Waite et al. [32]. The investigated locations may be ranked as follows: Imb3, Ita2, Ita3, Ita4, Ita6 and Ita8 as highly polluted (300–1000 ng (Sn) g−1 TBT), Bab1 and Bab2 as moderately polluted (60–200 ng (Sn) g−1 TBT) and Bab5 and Ita7 as slightly polluted (10–50 ng (Sn) g−1 TBT). According to this classification, sediments containing concentrations higher than 1000 ng (Sn) g−1 TBT (station Ita5) are likely to contain paint particles. According to the Australian sediment quality guidelines for TBT, the concentrations established as low and high trigger values are 5 and 70 ng (Sn) g−1 [33]. This classification places most of the sediment samples from these Santa Catarina harbors above the safety range and thus they represent a risk to the benthic organisms. The Sediment Quality Guidelines (SQGs) proposed by Dutch RIKZ (National Institute for Coastal and Marine Management) were also used as reference values to assess the impact of TBT levels found in Santa Catarina harbors. The maximum permissible concentrations and the negligible concentrations are 0.7 and 0.007 ng
Table 3 Bulk parameters and butyltin average concentrations (n = 3) in the sediments sampled at the Santa Catarina harbor regions. Station
Sand (%)
Silt (%)
Clay (%)
TOC (mmol g−1 )
TBT (ng (Sn) g−1 dw)
DBT (ng (Sn) g−1 dw)
MBT (ng (Sn) g−1 dw)
BTs
TBT/TOC
BDI
Bab1 Bab2 Bab3 Bab4 Bab5 Imb1 Imb2 Imb3 Imb4 Ita1 Ita2 Ita3 Ita4 Ita5 Ita6 Ita7 Ita8
26.9 49.5 65.2 35.0 68.7 82.0 64.6 55.8 52.4 16.6 25.4 17.6 6.3 14.3 1.2 33.3 19.5
70.6 43.2 32.7 60.7 27.2 16.8 28.3 40.0 44.3 56.9 67.3 72.7 76.5 75.4 85.1 59.3 70.6
2.4 7.3 2.1 4.3 4.1 1.1 7.0 4.2 3.3 26.5 7.3 9.7 17.2 10.3 13.7 7.4 10.0
1.74 2.64 1.14 2.04 1.06 0.43 1.05 2.98 1.41 0.89 1.06 1.45 1.46 1.51 1.58 1.79 1.56
125.0 88.5 n.d. n.d. 24.3 n.d. n.d. 428.9 n.d. n.d. 806.4 466.2 578.1 1136.6 857.8 39.1 445.6
394.4 n.d. n.d. n.d. 36.2 68.2 99.6 125.2 n.d. 115.2 n.d. 1.5 n.d. 36.2 32.6 19.8 14.0
312.2 45.4 n.d. n.d. 32.3 181.1 59.3 133.1 n.d. 48.2 n.d. 38.8 n.d. 94.9 106.7 28.6 126.3
831.5 134.0 n.d. n.d. 92.9 249.3 158.9 687.2 n.d. 163.4 806.4 506.5 578.1 1267.7 997.1 87.5 585.9
71.8 33.5 n.d. n.d. 23.0 n.d. n.d. 143.9 n.d. n.d. 760.8 321.5 396.0 752.7 542.9 21.8 285.6
5.7 0.5 n.d. n.d. 2.8 1 1 0.6 n.d. 1 1 0.1 1 0.1 0.2 1.2 0.3
Butyltin degradation index (BDI) = [MBT] + [DBT]/[TBT]; BTs = [TBT] + [DBT] + [MBT]; n.d. = not detectable, below LOD; Rsd below 20%.
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
855
Fig. 3. Mean distribution concentrations of tributyltin, dibutyltin, monobutyltin and total butyltin derivatives from sampling sites in Santa Catarina harbors. Sample locations are indicated in Fig. 1.
(Sn) g−1 dw, respectively, based on a standard sediment having 10% organic matter, or equivalently 5% organic carbon [34]. When normalized to total organic carbon, this corresponds to 0.014 g g−1 TOC and 0.00014 g g−1 TOC, respectively. Concentrations normalized to organic carbon contents are shown in Table 3. On comparing the organic carbon-normalized TBT contents in the sediments of Santa Catarina with the Dutch criteria, these TBT values exceeded the maximum permissible concentration, especially at stations Ita2, Ita3, Ita4, Ita5, Ita6, Ita8 and Imb3 from the Itajaí-Ac¸u River and Imbituba sites. The process of BTs sorption to sediments is fast and involves primarily particulate organic matter constituents that act as sorbents [35]. For this study, no correlation was found between BTs concentrations and the relative organic carbon contents in the sediments. Sedimentary BTs levels described in this study were also compared to those reported in different coastal areas of the southeast of Brazil. Fernandez et al. [22] found in Guanabara Bay values of TBT ranging from 10 to 520.9 ng (Sn) g−1 dw. Values detected along the São Paulo coast varied from 90 to 482 ng (Sn) g−1 dw in Santos Harbor, 224 to 847 ng (Sn) g−1 dw in Guarujá Marina and 17 to 53 ng (Sn) g−1 dw in the Cananéia region [24]. On the Paranaguá Estuarine complex located in Paraná State, TBT was found in all sediment samples, ranging from 363 to 2796 ng (Sn) g−1 dw [9]. Total BTs contents observed along the Brazilian coast are close to those reported by other authors worldwide [34,36]. Since they are high in areas dedicated to drydocking and marinas, it can be concluded that these activities are expressive sources of organotin contaminants in the local marine environment. Tributyltin degrades quickly in seawater, where it has a residence time of days. On the other hand, in sediments it tends to adsorb onto particles and the degradation processes are considerably slower [37]. A significant degradation of tributyltin to monosubstituted forms has been described by several authors. Generally, high TBT concentrations are found in impacted areas and it is assumed that the environment has been recently contaminated by BTs. However, when the concentration of monosubstituted derivatives found in sediments are higher, the contamination is considered to be historic or, alternatively, the processes of degradation may be faster. The degradation coefficient for OTC was defined by Díez et al. [18] and can be used to estimate the degree of BTs degradation at each location. Butyltin degradation index (BDI) values lower than 1 are indicative of recent input of contaminants and values higher than 1 can express the lack of recent influx. Considering the values for the degradation coefficient obtained (Table 3) and the distribution of butyltin derivatives (Fig. 3), the occurrence of historic contamination or faster degradation kinetics at stations Imb1, Imb2 and Ita1 can be inferred when compared to the other locations studied. At station Ita1, located at the mouth of the ItajaíAc¸u River, and at stations Imb1 and Imb2, located in an open inlet,
Fig. 4. Dendogram of the hierarchical cluster analysis for butyltin derivatives and BDI (butyltin degradation index) in surface sediments collected from harbors along the Santa Catarina coast.
the water column dynamics may also facilitate the sediment advection, associated with shipping traffic, river inputs and tidal effects. Considering the dissolved oxygen values at stations Imb1 and Imb2 (9.0 and 9.1 mg L−1 , respectively) the degradation processes may be faster than at station Ita1, with a lower DO value (2.2 mg L−1 ) and possibly historic contamination. Station Bab1 is an enclosed vessel dock, where dredging activities are periodic. Sediment mixing and uptake probably explain the higher proportion of DBT and MBT found at this site. In contrast, for station Bab5 the high BDI index can be attributed to historic contamination. This location has been used for the discarding of dredging residues. At stations Ita2 and Ita4 only TBT was found. These are located in the dock harbor and might be receiving and absorbing TBT antifouling paint recently released. This supposition might be attributed given the values found at the other sites of the Itajaí Valley close to these stations. Stations Ita3, Ita5, Ita6 and Ita8 also present lower values of DBI with expressive TBT concentrations. Station Ita7 is located at the mouth of Itajaí-Mirim River. The discharge of water and dissolution of pollutants might explain the low values found at this site. 3.3. Cluster analysis (CA) Hierarchical cluster analysis (HCA), the CA method most frequently applied to environmental analysis, groups samples according to their similarities. HCA is a powerful tool for analyzing data sets for expected or unexpected clusters including the presence of outliers. In HCA, the most similar points are grouped forming one cluster and the process is repeated until all points belong to one cluster. This analysis examines distances between samples and data sets. In the current study, the single linkage HCA method was applied to the data for the surface sediments, using Euclidian distances. The data matrix examined includes the concentrations of butyltin derivatives and BDI in relation to locations in the study area. The aim of the HCA was to consider the highest number of variables which can characterize the impact of BTs. The result is shown in a dendogram (Fig. 4). A total number of four groups were observed. The dendogram suggests that the groupings were primarily correlated to TBT contents. The association of Imb1, Imb2 and Ita1 can be classified as historic contamination, since only DBT and MBT were found. Locations Bab2, Bab5 and Ita7 are gathered together in the same group due to lower TBT contents in comparison to the other stations; and station Bab2 showing lower BDI values. Stations
856
C.R. de Oliveira et al. / Journal of Hazardous Materials 181 (2010) 851–856
Imb2, Ita3, Ita3, Ita4, Ita5, Ita6 and Ita8 form the biggest group. The similarity of the samples in this group is the high concentrations of TBT in contrast to DBT and MBT. In addition, the low BDI values found in this group represent recent input of contaminants. Station Bab1 shows a high BDI value. However, the TBT content is also high when compared to the stations with historic inputs. For this reason, it does not show strong similarity with the other locations. 4. Conclusions For the first time the sediment contamination levels at São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors were assessed using GC-PFPD. This study revealed that despite the total ban on the use of TBT in January 2008 these harbor regions may act as “hotspots” of pollution. This species has been used as a biocide in marine antifouling paints. BTs contents vary widely and are dependent on the station location and the individual characteristics of each harbor. The magnitude of the contamination was consistent with values reported for sediments in commercial harbors and marinas worldwide. Substantial amounts of the degradation products DBT and MBT were determined in this study, indicating that natural attenuation is contributing to sediment remediation. Because harbor regions are of crucial economical interest, it is clear that a larger spatio-temporal organotin monitoring program needs to be set up, in order to continuously evaluate the level of BTs contamination in the Santa Catarina coastal area. Acknowledgments Thanks are due to the Rescue & Save Brigade of Itajaí for helping us to collect samples at the Itajaí-Ac¸u River. Scholarship for C. R. Oliveira was provided by CAPES. Financial support was provided by Petrobras and FAPESC. References [1] M. Hoch, Organotin compounds in the environmental–an overview, Appl. Geochem. 16 (2001) 719–743. [2] Y. Morcillo, C. Porte, Evidence of endocrine disruption in clams Ruditapes decussata-transplanted to a tributyltin-polluted environment, Environ. Pollut. 107 (2000) 47–52. [3] G.M. Gadd, Microbial interactions with tributyltin compounds: detoxification, accumulation, and environmental fate, Sci. Total Environ. 258 (2000) 119–127. [4] H.L. Tan, B. Clarcke, D. Lockington, Analysis of Organotin (TBT) in the Environment and Analytical Methods, Tese, CHEE 4006/7, The University of Queensland, Australia, 2004. [5] C.J. Buggy, J.M. Tobin, Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland, Environ. Pollut. 143 (2006) 294–303. [6] D. Cao, G. Jiang, Q. Zhou, R. Yang, Organotin pollution in China: an overview of the current state and potential risk, Environ. Manage. 90 (2009) S16–S24. [7] M.A. Champ, Economic and environmental impacts on ports and harbors from the convention to ban harmful marine anti-fouling systems, Mar. Pollut. Bull. 46 (2003) 935–940. [8] M.A. Fernandez, F.M. Pinheiro, New approaches for monitoring the marine environment: the case of antifouling paints, Int. J. Environ. Health 1 (2007) 427–448. [9] D.M. Santos, I.P. Araújo, E.C. Machado, M.A.S. Carvalho-Filho, M.A. Fernandez, M.R.R. Marchi, A.F. Godoi, Organotin compounds in the Paranaguá Estuarine Complex, Paraná, Brazil: evaluation of biological effects, surface sediment, and suspended particulate matter, Mar. Pollut. Bull. (2009), doi:10.1016/j.marpolbul.2009.09.004. [10] L.W. Hall, A.E. Pinkney, Acute and sublethal effects of organotin compounds on aquatic biota: an interpretative literature evaluation, Crit. Rev. Toxicol. 14 (1985) 159–167. [11] M.C. Lau, K.M. Chan, K.M.Y. Leung, T.G. Luan, M.S. Yang, J.W. Qiu, Acute and chronic toxicities of tributyltin to various life stages of the marine polychaete Hydroideselegans, Chemosphere 69 (2007) 135–144.
[12] T. Horiguchi, H. Shiraishi, M. Shimizu, M. Morita, Effects of triphenyltin chloride and five other organotin compounds on the development of imposex in the rock shell, Thais Clavigera, Environ. Pollut. 95 (1) (1997) 85–91. [13] M.H. Depledge, Z. Billinghurst, Ecological significance of endocrine disruption in marine invertebrates, Mar. Pollut. Bull. 39 (1–12) (1999) 32–38. [14] P. Mathiessen, P.E. Gibbs, Critical appraisal of the evidence for tributyltinmediated endocrine disruption in molluscs, Environ. Toxicol. Chem. 17 (1998) 37–43. [15] A.M. Limaverde, A.L.R. Wagener, M.A. Fernandez, A.L. Scofield, R. Coutinho, Stramonitahaemastoma as a bioindicator for organotin contamination in coastal environments, Mar. Environ. Res. 64 (2007) 384–398. [16] E. Millán, J. Pawliszyn, Determination of butyltin species in water and sediment by solid-phase microextraction-gas chromatography-flame ionization detection, J. Chromatogr. A. 873 (2000) 63–71. [17] S. Aguerre, G. Lespes, V. Desauziers, M. Potin-Gautier, Speciation of organotins in environmental samples by SPME-GC: comparison of four specific detectors: FPD, PFPD, MIP-AES and ICP-MS, J. Anal. Atom. Spectrom. 16 (2001) 263– 269. [18] S. Díez, M. Ábalos, J.M. Bayona, Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation, Water Res. 36 (2002) 905–918. [19] S. Tsunoi, T. Matoba, H. Shioji, L.T.H. Giang, H. Harino, M. Tanaka, Analysis of organotin compounds by Grignard derivatisation and gas chromatography–ion trap tandem mass spectrometry, J. Chromatogr. A 962 (2002) 197–206. [20] C. Devos, M. Vliegen, B. Willaert, F. David, L. Moens, P. Sandra, Automated headspace-solid-phase micro-extraction–retention time locked-isotope dilution gas chromatography–mass spectrometry for the analysis of organotin compounds in water and sediment samples, J. Chromatogr. A 1079 (2005) 408–414. [21] A.F.L. Godoi, R.C. Montone, M. Santiago-Silva, Determination of butyltin compounds in surface sediments from the São Paulo State coast (Brazil) by gas chromatography-pulsed flame photometric detection, J. Chromatogr. A 985 (2003) 205–210. [22] M.A. Fernandez, A.L.R. Wagener, A.M. Limaverde, A.L. Scofield, F.M. Pinheiro, E. Rodrigues, Imposex and surface sediment speciation: a combined approach to evaluate Organotin contamination in Guanabara Bay, Rio de Janeiro, Brazil, Mar. Environ. Res. 59 (2005) 435–452. [23] M.J. Cremer, P.R.D. Morales, T.M.N. Oliveira, Diagnóstico Ambiental da Baía da Babitonga Joinville, SC, UNIVILLE Press, Joinville, Brazil, 2006. [24] J.P. Filho, L.C. Spillere, C.A.F. Schettini, Dinâmica de nutrientes na região portuária do estuário do Rio Itajaí-Ac¸u, SC, Atlântica (Rio Grande) 25 (1) (2003) 11–20. [25] K. Suguio, Introduc¸ão à Sedimentologia, Edgard Buckler, EDUSP, São Paulo, 1973. [26] EURACHEM-The Fitness for Purpose of Analytical Methods, A laboratory guide to method validation and related topics, LGC (Teddington) Ltd., London, 1998, p. 75. [27] IUPAC (International Union of Pure and Applied Chemistry), Analytical, applied, clinical, inorganic, and physical chemistry divisions interdivisional working party for harmonization of quality assurance schemes for analytical laboratories, Pure Appl. Chem. 74 (2002) 835–855. [28] M. Ribani, C.B.G. Bottoli, C.H. Collins, I.C.S.F. Jardim, L.F.C. Melo, Validac¸ão em métodos cromatográficos e eletroforéticos, Quim. Nova 27 (2004) 771–780. [29] K.A. Burns, P.F. Greenwood, R.E. Summons, G.J. Brunskill, Vertical fluxes of hydrocarbons on the Northwest Shelf of Australia as estimated by a sediment trap study, Org. Geochem. 32 (10) (2001) 1241–1255. [30] L. Mater, M.R. Alexandre, F.A. Hanzel, L.A.S. Madureira, Assessment of lipid compounds and phosphorus in mangrove sediments of Santa Catarina Island, SC, Brazil, J. Braz. Chem. Soc. 15 (2004) 1–10. [31] C. Marcic, I.L. Hecho, L. Denaix, G. Lespes, TBT and TPhT persistence in a sludged soil, Chemosphere 65 (2006) 2322–2332. [32] M.E. Waite, M.J. Waldock, J.E. Thain, D.J. Smith, S.M. Milton, Reductions in TBT concentrations in UK estuaries following legislation in 1986 and 1987, Mar. Environ. Res. 32 (1991) 89–111. [33] ANZECC/ARMCANZ, Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council/Agricuture and Resource Management Council of Australian and New Zealand, Canberra, 2000. [34] S. Díez, J.M. Bayona, Butyltin occurrence and risk assessment in the sediments of the Iberian Peninsula, J. Environ. Manage. 90 (2009) S25–S30. [35] M. Berg, C.G. Arnold, S.R. Muller, J. Muhlemann, R.P. Schwarzenbach, Sorption and desorption behavior of organotin compounds in sediment-pore water systems, Environ. Sci. Technol. 35 (2001) 3151–3157. [36] N.B. Bhosle, A. Garg, R. Harji, S. Jadhav, S.S. Sawant, V. Krishnamurthy, C. Anil, Butyltins in the sediments of Kochi and Mumbai harbours, west coast of India, Environ. Int. 32 (2006) 252–258. [37] P.M. Sarradin, Y. Lapaquellerie, A. Astruc, C. Latouche, M. Astruc, Long term behaviour and degradation kinetics of tributyltin in a marina sediment, Sci. Total Environ. 170 (1995) 59–70.