Butyltins biomagnification from macroalgae to green sea urchin: a field assessment

Biomagnification of butyltins (BTs) was examined in a simple food web including seawater, macroalgae (Alaria esculenta, Laminaria longicruris, Ulvaria obscura) and green urchin (Strongylocentrotus droebachiensis). The study was conducted in shallow waters of the St Lawrence Estuary (Canada) adjacent to two areas potentially contaminated by BTs. Levels of tri‐ (TBT), di‐ (DBT) and mono‐BT (MBT) were determined in seawater, green urchin (including faecal matter after sampling) and macroalgae surrounding the urchins at each sampling site. The concentrations of TBT in seawater from all stations were relatively low (3–7 ngSn l^?1), and both the TBT and the total BTs (∑BT = MBT + DBT + TBT) concentrations decreased with increase in distance from the BT sources. The concentrations of TBT in algae were 0.35 ngSn g^?1 dry weight (DW) in A. esculenta, 0.40 ngSn g^?1 DW in L. longicruris and 3.58 ngSn g^?1 DW in U. obscura. Following their location, green urchins feeding mainly on these algae accumulated BTs at levels ranging from 4 to 85 ngSn g^?1 DW in gonads and from 35 to 334 ngSn g^?1 DW in gut. The mean bioconcentration factor (BCF) calculated from seawater to algae ranged from 17 in A. esculenta to 151 in U. obscura, whereas the biomagnification factor (BMF) from algae to urchins ranged from 2 to 17 in gonads and from 10 to 67 in gut. The overall bioaccumulation factor of TBT between seawater and internal organs of urchins reached an average value of 1.2 × 10³. These results are the first to illustrate high BT BCFs and BMFs in human‐edible macroalgae and urchins sampled from northern coastal areas with a low TBT contamination level. Copyright © 2003 John Wiley & Sons, Ltd.     

Degradation of dibutyltin in sea water by pyoverdins isolated from Pseudomonas chlororaphis

The yellow compounds pyoverdins were isolated from Pseudomonas chlororaphis, which was isolated from mud in Japan. Degradation of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) by pyoverdin (20 mg) was carried in sea water (30 ml) containing a 6 µg l^?1 concentration of TBT, DBT, and MBT at 24 °C for 24 h in aerobic conditions. TBT, DBT, and MBT in sea water were analyzed by gas chromatography–mass spectrometry in selected ion monitoring mode. DBT in sea water was degraded to MBT by pyoverdins isolated from P. chlororaphis. However, TBT and MBT in sea water was not degraded by pyoverdins. The optimum degradation of DBT in sea water was at pH 4.8–8.2, at a temperature 25–30 °C. Copyright © 2002 John Wiley & Sons, Ltd.     

Measurement of butyltin contamination of water and sediment in Osaka Bay,Japan

The concentration of tributyltin (TBT) in surface water from Osaka Bay ranged from 0.023 to 0.061 µg l⁻¹ in 1989 and from not detected (ND) to 0.059 µg l⁻¹ in 1990 while the proportion of TBT as a percentage of the total butyltins (BTs) was more than 40%. The concentration of TBT was also surveyed in the Port of Osaka and the Yodo River basin. TBT levels were highest in the estuary (the Port of Osaka), followed by sea areas (Osaka Bay) and rivers (Yodo River basin). A fairly high correlation coefficient between TBT concentration and salinity in water from the estuary and the sea areas was observed. This result shows that the TBT in the estuary water is diluted by seawater. Generally, the TBT concentrations in the water columns were distributed uniformly and the composition of the BTs was also constant. TBT was detected in sediment from Osaka Bay in the range from ND to 0.023 mg kg⁻¹ dry weight with a high ratio of monobutyltin (MBT) to the total BTs. TBT in sediment core was also measured; its concentration decreased with core depth. It was estimated from these measurements that the release of TBT into Osaka Bay began in the 1960s. Copyright © 1998 John Wiley & Sons, Ltd.     

Selective non-chromatographic determination of tributyltin in sediments using EDTA and diphenylcarbazone as masking agent

Two analytical procedures based on the generation of volatile tributyltin derivatives, their separation by headspace solid-phase microextraction (HS SPME) and subsequent determination using plasma optical emission spectrometry (OES) have been developed for the selective determination of trace tributyltin (TBT) in the presence of other butyltins and inorganic tin in sediments without the use of chromatography. A microwave-assisted leaching of tin compounds from the sediment using 25%_v/v acetic acid is applied for sample pretreatment. The first method takes advantage of TBT chloride releasing from the lecheate after adding 3 M hydrochloric acid, and subsequent separation of the analyte by HS SPME using Carboxen-poly(dimethylsiloxane) (CAR/PDMS). The second method involves the use of masking agents, namely ethylenediaminetetraacetic acid (EDTA) and diphenylcarbazone (DFC), which form stable chelates with monobutyltin (MBT) and dibutyltin (DBT), respectively, followed by the ethylation of tributyltin at pH 5 using sodium tetraethylborate (NaBEt4) solution. The final concentration of NaBEt4 is 0.05%_w/v. The parameters affecting the TBT derivatisation and separation by HS SPME have been optimised including the selection of SPME fibre coating (PDMS, CAR/PDMS), the amount of masking agents and NaBEt4 added, sorption time (2–40 min) and sorption temperature (25–60°C). Higher sensitivity and robustness are attained with the method involving ethylation derivatisation, leading to the limit of detection (LOD) of 3 ng L^?1. The selective release of TBT is observed from aqueous solutions, where the concentrations of MBT and DBT were in 2–50-fold excess to TBT. The SPME-TD-MIP-OES methods have been validated against several certified reference materials (CRMs), including SOPH-1 marine sediment, PACS-2 marine sediment and BCR 646 freshwater sediment.     

Butyltin compounds in severn sound,lake huron,canada

Severn Sound is a heavily used recreational and beating area in the southeast corner of Georgian Bay, Lake Huron, Canada. Because of the concern over the possible release of tributyltin species (TBT) from antifouling paints on boat hulls and marinas, surveys were carried out in 1989 and 1992 to determine the presence of this species and its degradation products dibutyltin (DBT) and monobutyltin (MBT) in this area. Many fish (pike and young–of–the–year spottail shiners) and sediment samples collected in 1989 contained detectable levels of TBT. A maximum concentration of TBT was recorded in northern pike in the spring to be 240 ng Sn g^?1. Maximum levels occurred in marinas during the beginning of the boating season and significantly reduced during the summer and early autumn, although the maximum value of TBT in sediment (392 ng Sn g^?1) was observed in the summer of 1989. The seasonal variation of TBT levels was further substantiated in the subsequent 1992 study, in which sediments from three areas in a marina were sampled at monthly intervals from May to October. TBT levels were much higher in May and then generally decreased with time. Mussels (Elliptio complanta) caged in the marina for three months also contained TBT. DBT was frequently detected in the sediments but less frequently in fish and mussels. MBT was generally below detection limits. Plants (macrophytes and cladophora) contained very small amounts of butyltin compounds.     

Imposex and organotin contamination in Nassarius reticulatus (L.) along the Portuguese coast

Nassarius reticulatus (whelk) imposex levels and organotin body burden (b.b.) were surveyed along the Portuguese coast, from Vila Praia de Âncora (northern limit) to Lagos (southern limit), between May and August 2003. The percentage of females affected with imposex (%I), the relative penis length index (RPLI), the vas deferens sequence index (VDSI) and the degree of female oviduct convolution index (AOS) were used to assess the level of imposex at each site. These imposex indices were determined for 23 sampling stations throughout the coast and were in the range 0.0–100%, 0.0–90%, 0.0–5.0 and 0.0–1.3 respectively. Sterile females (i.e. females carrying aborted egg capsules inside the capsule gland) were found inside the harbours of Viana do Castelo (8.5%) and Aveiro (3.7%). Organotin compounds were assessed at 10 sampling sites spread along the coast. Tributyltin (TBT) b.b. in females varied between 39 and 1679 ng g^?1 (as tin) dry weight, and dibutyltin (DBT) and monobutyltin (MBT) varied in the ranges 23–1084 ng g^?1 (as tin) d and 18–939 ng g^?1 dry wt respectively. Among the butyltins, the major fraction corresponded to TBT (47.4%), followed by DBT (27.6%) and MBT (25.0%), which indicates recent TBT inputs. Triphenyltin (TPT) levels ranged from <5 to 21 ng g^?1 (as tin), and, when quantifiable, represented on average 10% of that of TBT. TPT was the dominant phenyltin and was detected in 60% of the sampling stations. The imposex was significantly correlated to ln (TBT) (Spearman r = 0.918, p < 0.001 for RPLI; r = 0.864, p < 0.001 for VDSI; r = 0.828, p < 0.01 for AOS). The higher levels of imposex and TBT contamination occurred inside or close to harbours, which we identified as ‘hotspots’ of pollution along the coast. Comparing the results obtained in the current work with those reported in a similar survey in 2000, imposex and TBT b.b. varied locally but did not reveal any global trend in the variation of TBT pollution along the Portuguese coast over the 3 year period. Copyright © 2005 John Wiley & Sons, Ltd.     

Headspace solid-phase micro-extraction and gas chromatography-ion trap tandem mass spectrometry method for butyltin analysis in sediments: Optimization and validation

In this work, headspace solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) method for analysis of butyltin compounds in sediment samples was upgraded by the introduction of tandem mass spectrometry (MS/MS). Optimization and validation of this method based on an one step procedure, tetraethylborate in situ ethylation with simultaneous extraction by headspace SPME, combined with tandem mass spectrometry is described. A simple leaching/extraction step of mono-(M), di-(D) and tri-(T) butyltin (BT) compounds from the sediment is required as sample pre-treatment. The combination of the two techniques headspace SPME and MS/MS, led to very little matrix interference which permitted to attain limits of detection three or more orders of magnitude lower than those attained in previous methods: 0.3 pg g^− 1 for MBT, 1 pg g^− 1 for DBT and 0.4 pg g^− 1 for TBT. Linear response range was from 0.02–1260 ng g^− 1 for MBT, 0.07–1568 ng g^− 1 for DBT and 0.04–2146 ng g^− 1 for TBT and RSD < 15% was also obtained. The method was efficiently applied to a real sample sediment from Sado River estuary in Portugal, revealing the existence of BTs pollution, as the TBT level of 189 ± 15 ng g^− 1 was much higher than the maximum established as provisional ecotoxicological assessment criteria.     

A study of the partitioning and sorptive behaviour of butyltins in the aquatic environment

This study was designed to investigate the partitioning and sorptive behaviour of tributyltin(TBT), and its degradation products dibutylitin (DBT) and monobutyltin (MBT), in the aquatic environment. Factorial experiments were undertaken to determine the importance of pH and particulate matter concentration in the sorption of butyltin compounds to solid phases. Results indicate that in freshwaters MBT, and to a lesser extent TBT, will be partitioned towards the particulate phase, whereas DBT exhibits a 50:50 partitioning between particulate and solution phases. In estuarine waters, whilst MBT will almost exclusively sorb on to particulates, TBT will be predominantly in the solid-phase fractions but 10–30% may remain in solution. DBT, in contrast, is solubilized in estuarine waters. A more detailed investigation of TBT sorption and particulate matter concentration was undertaken using adsorption isotherms on different sediment types. The results from batch isotherm tests plotted according to the Freundlich adsorption model revealed that TBT adsorption varied with sediment type, increasing in the order sandy-silt < silty-sand < silty-clay. TBT sorption was found to be reversible, indicating that contaminated sediments may release TBT to overlying waters following sediment distrubance. Interstitial water partitioning studies indicate that TBT predominates in the particulate phase with partition coefficients for TBT higher than for DBT and MBT. The TBT partition coefficient in interstitial waters appears to be related to total organic carbon loadings.     

Isotope dilution GC-MS routine method for the determination of butyltin compounds in water

A standard GC-MS instrument with electron impact ionisation has been used to develop a fast, simple and reliable method for the simultaneous determination of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in water samples. Isotope dilution analysis (IDA) is used for the determination of species, taking advantage of a commercially available spike solution containing a mixture of MBT, DBT and TBT enriched in ¹¹⁹Sn. Method detection limits for 100-mL samples were between 0.18 and 0.25 ng L⁻¹ for the three butyltin compounds with typical RSD between 2 and 4% at levels between 100 and 10 ng L⁻¹, respectively. Recovery of tin species in spiked samples (natural water, wastewater and seawater) was quantitative. The stability of butyltin compounds in collected seawater samples was also studied. The addition of a 1% (v/v) glacial acetic acid preserved tin species in the samples for at least 5 days at room temperature. The IDA method was finally implemented in a routine testing laboratory and it was subsequently accredited by the Spanish National Accreditation Body according to the requirements of UNE-EN ISO/IEC 17025.     

Levels of polycyclic aromatic hydrocarbons,polychlorinated byphenyls,methylmercury and butyltins in the natural UNESCO reserve of the biosphere of Urdaibai (Bay of Biscay,Spain)

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), methylmercury (MeHg⁺) and butyltins (mono-, di- and tri-butyltin, MBT, DBT and TBT) were monitored in oysters (Crassostrea sp.) and sediments collected in different sampling points of the UNESCO reserve of the biosphere of Urdaibai (Bay of Biscay) from March 2006 to June 2007. In the case of oyster samples, concentrations in the 290–1814 µg kg^?1 (PAHs), 70–475 µg kg^?1 (PCBs), 75–644 µg kg^?1 (MeHg⁺) and 200–1300 µg kg^?1 (as a sum of the three butyltins) ranges were obtained. In most samples TBT was the most abundant butyltin, followed by DBT and MBT. It should be highlighted that most samples exceeded the highest range (367 µg kg^?1) found in the last mussel watch programme carried out by the National Oceanic and Atmospheric Administration (NOAA) for butyltins in oyster samples. This could be due to the presence of a shipyard in the estuary. Sediment concentrations ranged as follows: total PAHs (856–3495 µg kg^?1) and total PCBs (58–220 µg kg^?1). Organometallic species were always below the limits of detection (LODs) (0.24 µg kg^?1 for MeHg⁺, 0.6 µg kg^?1 for MBT, 0.48 µg kg^?1 for DBT and 1.1 µg kg^?1 for TBT). In both sediment and oyster PAH sources were mostly combustion. In the case of PCBs, 4-6 chlorine-atom congeners were the most abundant ones. Slight differences in the profile of PAHs as well as PCBs can be detected when the matrices were compared with each other. Finally, in the case of PAHs, sediment and water column played the main role in the accumulation pathway into the organisms in all the sampling stations.     

Speciation of butyltin compounds in marine sediments with headspace solid phase microextraction and gas chromatography mass spectrometry

A method for the determination of organotin compounds (monobutyl = MBT, dibutyl = DBT, and tributyltin = TBT) in marine sediments by headspace Solid Phase Microextraction (SPME) has been developed. The analytical procedure involved 1) extraction of TBT, DBT and MBT from sediments with HCl and methanol mixture, 2) in situ derivatization with sodium tetraethylborate and 3) headspace SPME extraction using a fiber coated with poly(dimethylsiloxane). The derivatized organotin compounds were desorbed into the splitless injector and simultaneously analyzed by gas chromatography - mass spectrometry. The analytical method was optimized with respect to derivatization reaction and extraction conditions. The detection limits obtained for MBT, DBT and TBT ranged from 730 to 969 pg/g as Sn dry weight. Linear calibration curves were obtained for all analytes in the range of 30-1000 ng/L as Sn. Analysis of a standard reference sediment (CRM 462) demonstrates the suitability of this method for the determination of butyltin compounds in marine sediments. The application to the determination of TBT, DBT and MBT in a coastal marine sediment is shown.     

A quantitative extraction method for the determination of trace amounts of both butyl- and phenyltin compounds in sediments by gas chromatography-inductively coupled plasma mass spectrometry

A simple and reliable extraction method was developed for quantitative determination of both butyl- and phenyltin compounds in sediments by capillary gas chromatography combined with inductively coupled plasma mass spectrometry (GC-ICP-MS). Both types of organotin compounds were extracted quantitatively from sediment by mechanical shaking into tropolone-toluene and HCl-methanol. After phase separation and pH adjustment, these organotins were ethylated with sodium tetraethylborate. The method was evaluated by analyzing PACS-2 and NIES No. 12 sediment certified reference materials. The dibutyltin (DBT; 1.14 +/- 0.02 micrograms g-1) and tributyltin (TBT; 1.01 +/- 0.04 micrograms g-1) values observed in PACS-2 sediment closely matched the certified values (DBT, 1.09 +/- 0.15; TBT, 0.98 +/- 0.13 microgram g-1 as tin). The monobutyltin (MBT) value was higher (0.62 +/- 0.02 microgram g-1) by more than two fold over the reference value (0.3 microgram g-1 as tin). The concentrations of TBT (0.18 +/- 0.04 microgram g-1) and triphenyltin (TPhT; 0.0099 +/- 0.002 microgram g-1) in the NIES No. 12 sediment were also in good agreement with the certified and reference values of TBT (0.19 +/- 0.03 microgram g-1 as compound) and TPhT (0.008 microgram g-1 as compound), respectively. Recoveries of TBT, tripentyltin (TPeT) and TPhT from spiked sediments were satisfactory (TBT, 102 +/- 3.4%; TPrT, 96 +/- 3.4%; TPhT, 99 +/- 8.5%). The detection limits as tin were in the range 0.23-0.48 ng g-1 for a 0.5 g sample size. It is also noteworthy that clean-up of the extract is not necessary because of the superior selectivity of ICP-MS detection. The present method was successfully applied to marine sediment samples.     

Electrochemical speciation of organotin compounds in water and sediments. Application to sea water after ion-exchange separation

For the quantitative speciation of tributyltin, Bu₃Sn⁺ (TBT), in the presence of dibutyltin, Bu₂Sn²⁺ (DBT), monobutyltin, BuSn³⁺ (MBT), triphenyltin, Ph₃Sn⁺ (TPT), and inorganic tin in water samples and sediments, an accurate, reproducible, simple and rapid electrochemical method was developed. After extraction of the organotin compounds with dichloromethane, TBT could be selectively determined as species by alternating current polarography directly in the organic phase without any derivatisation. The successful application of this technique could be proved by the results obtained by intercomparison exercises on TBT in water samples and sediments, organized by the Community Bureau of Reference (BCR). For the application of this technique to sea water samples a preliminary ion exchange separation of TBT from the major components of sea water was performed, achieving a detection limit for TBT in the ppt range.     

Accumulation of butyltin compounds in dolphins stranded along the Mediterranean coasts

Concentrations of tributyltin (TBT) and its degradation products, monobutyltin (MBT) and dibutyltin (DBT), were determined in the liver and kidney of striped dolphins ( Stenella coeruleoalba), bottlenose dolphins ( Tursiops truncatus) and in a fetus of the common dolphin (Delphinus delphi) found stranded along the western Italian and Greek coasts in the period 1992–1994. Butyltin (BT) compounds were detected in almost all the samples analyzed and were higher in the kidney than in the liver. Total BT concentrations were 0.78–8.05 μg g⁻¹ wet wt in kidney and 0.015–1.02 μg g⁻¹ wet wt in liver of S. coeruloealba. Bottlenose dolphins had lower BT concentrations than striped dolphins. Although only one fetal sample was analyzed, it showed the highest BT concentrations of all. Unlike BT concentrations in the other adult dolphins, in the pregnant dolphin they were higher in the liver (4.35 μg g⁻¹ wet wt), suggesting that BTs are transferred from mother to fetus. No significant differences in BT concentrations were found between sexes. Of the breakdown products, DBT was predominant in most liver samples and MBT was more abundant in kidney. Although BT concentrations are known to be found in cetaceans inhabiting waters of developed countries, our observations strongly suggest that concentrations found in S. coeruleoalba were either similar to or higher than those reported for other Stenella species collected from coastal areas close to harbors or marinas. Copyright © 2000 John Wiley & Sons, Ltd.     

Certification of butyltins and phenyltins in marine sediment certified reference material by species-specific isotope-dilution mass spectrometric analysis using synthesized <Superscript>118</Superscript>Sn-enriched organotin compounds

A new marine sediment certified reference material, NMIJ CRM 7306-a, for butyltin and phenyltin analysis has been prepared and certified by the National Metrological Institute of Japan at the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Candidate sediment material was collected at a bay near industrial activity in Japan. After air-drying, sieving, and mixing the material was sterilized with γ-ray irradiation. The material was re-mixed and packaged into 250 glass bottles (15 g each) and these were stored in a freezer at −30 °C. Certification was performed by use of three different types of species-specific isotope-dilution mass spectrometry (SSID–MS)—SSID–GC–ICP–MS, SSID–GC–MS, and SSID–LC–ICP–MS, with ¹¹⁸Sn-enriched organotin compounds synthesized from ¹¹⁸Sn-enriched metal used as a spike. The ¹¹⁸Sn-enriched mono-butyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were synthesized as a mixture whereas the ¹¹⁸Sn-enriched di-phenyltin (DPhT) and triphenyltin (TPhT) were synthesized individually. Four different extraction methods, mechanical shaking, ultrasonic, microwave-assisted, and pressurized liquid extraction, were adopted to avoid possible analytical bias caused by non-quantitative extraction and degradation or inter-conversion of analytes in sample preparations. Tropolone was used as chelating agent in all the extraction methods. Certified values are given for TBT 44±3 μg kg⁻¹ as Sn, DBT 51 ± 2 μg kg⁻¹ as Sn, MBT 67 ± 3 μg kg⁻¹ as Sn, TPhT 6.9 ± 1.2 μg kg⁻¹ as Sn, and DPhT 3.4 ± 1.2 μg kg⁻¹ as Sn. These levels are lower than in other sediment CRMs currently available for analysis of organotin compounds.     

Optimization of GC-ICPMS system parameters for the determination of butyltin compounds in Hungarian freshwater origin sediment and mussel samples

The optimization and application of gas chromatograph coupled with inductively coupled plasma mass spectrometer (GC-ICPMS) (equipped with a commercially available interface) for the speciation of butyltin compounds in freshwater origin sediment and mussel samples is described. Optimization focused on the system parameters that have the greatest effect on signal intensity such as plasma power, ion lenses and make up gas flow (in the interface). Xenon (Xe) containing argon gas (Ar) was applied as tuning gas providing continuous Xe signal for the optimization of system parameters. It was found that plasma power and make up gas are interrelated variables and provide a set of paired optimum values at each power settings. The absolute optimum values obtained at 800 W plasma power and 1.2 L min⁻¹ make up gas flow rate when 7 mm sample depth was adjusted. The optimum settings obtained were then checked by means of a test solution (tetraethyltin dissolved in hexane). Same optimum conditions were found when tin (Sn) transient signals were monitored. Detection limits were calculated for the three species using the optimized system parameters. Detection limits are the following: for monobutyltin (MBT) 5.6 ng Sn kg⁻¹, for dibutyltin (DBT) 6.6 ng Sn kg⁻¹ and for tributyltin (TBT) 3.4 ng Sn kg⁻¹ obtained. Determination of the butyltin compounds were carried out by means of species-specific isotope dilution analysis. The spike solution contained all species investigated but with altered isotopic composition. Each species were enriched in their ¹¹⁹Sn isotope. Concentrations found in Hungarian freshwater origin mussel and sediment samples ranged between 19 and 39 ng g⁻¹for MBT, between 1.2 and 6.3 ng g⁻¹ for DBT and between 1.2 and 3.2 ng g⁻¹ for TBT indicated as Sn in dry weight. Validation of the method was done by means of certified reference materials (BCR CRM 646 and 477). Good agreement was found between certified and experimental values. Normalized deviation (E_n) was also computed in order to validate the method used. E_n values obtained ranged between 0.07 and 0.11 for mussel samples and between 0.26 and 0.72 for sediment samples. These values show that isotope dilution-GC-ICPMS methodology is valid for the determination of MBT, DBT and TBT from both types of matrices.     

Optimization of a Liquid–Liquid Extraction Procedure of Butyltin Compounds and Total Tin in Marine Water Samples Using Flame Atomic Absorption Spectrometry

Two liquid–liquid extraction procedures have been optimized for analysis of sea water samples. Tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) compounds were extracted with tropolone in chloroform from samples acidified to 1Mwith HCl. The extracts were evaporated to dryness and redissolved in methanol, prior to separation of the alkytin compounds by liquid chromatography. Total tin was extracted from samples at pH 2 using oxine in isobutylmethylketone (IBMK). The optimized extraction procedure for alkyltin compounds was used as a pretreatment of the samples when the speciation of tin was being performed. The IBMK solutions obtained from the extraction of total tin were directly subjected to electrothermal atomic absorption spectrometry, using zirconium-coated graphite tubes with L'vov platforms.     

Liquid–solid extraction of butyltin compounds from marine samples

Environmental damage due to organotins (TBT, DBT, MBT) released from antifouling paints is well documented. The concentrations of these compounds in seawater are usually at ppt (parts per 10¹²) levels. Many analytical techniques, including chromatographic and spectrophotometric ones, have been presented in the literature to detect organotins at these low levels. Liquid-liquid extraction is commonly employed as a concentration method. However, it presents some disadvantages during sampling campaigns and requires large volumes of toxic and expensive solvents. In this paper we propose an analytical method based on a liquid-solid extraction procedure that can be easily performed in the field and is characterized by good recoveries and high enrichment factors. Three different solid phases (Carbopack, LC 8 and LC 18) and five different eluting agents (methanol/tropolone, methanol, dichloromethane, hexane and diethyl ether) were evaluated. Carbopack and LC 18 were the most suitable solid phases. Inorganic tin was not retained on these solid phases and a separation of TBT from DBT and MBT was achieved, performing the elution in two steps with methanol and methanol/tropolone. In this way GF AA was suitably employed to obtain butyltin speciation data.     

Modulation of the F1FO‐ATPase function by butyltin compounds

Among butyltin compounds, tributyltin (TBT), widely exploited in the past in antifouling paints for its biocidal properties, is long known as one of the most harmful sea contaminants. Among the ascertained and universal toxicity mechanisms, TBT targeting F₁F_O‐ATPase and thus impairing cell bioenergetics, is here reviewed. While TBT effects on F₁F_O‐ATPase have been investigated for decades, the possible impact of the derivatives dibutyltin (DBT) and monobutyltin (MBT), produced by abiotic and/or biotic dealkylation of TBT and usually considered far less toxic, have been poorly explored up until now. Butyltin effects on F₁F_O‐ATPase and their underlying action mechanism seem to be tightly structure dependent. Butyltins are membrane‐active toxicants. Owing to its more pronounced lipophilicity TBT targets the transmembrane F_O sector, blocks ionic translocation and causes a dose‐dependent loss of sensitivity to F_O inhibitors such as oligomycin and N,N′‐dicyclohexylcarbodiimide. DBT strongly inhibits F₁F_O‐ATPase activity by competing with the Mg⁺² cofactor in the F₁ catalytic site but is ineffective on the enzyme sensitivity to F_O inhibitors. MBT is apparently ineffective. The possible contribution of DBT to the overall butyltin toxicity on membrane systems may not be neglectable since usually TBT coexists with its derivatives in organotin‐exposed animal tissues. Copyright © 2013 John Wiley & Sons, Ltd.     

Contamination by butyltin compounds in harbour porpoise (Phocoena phocoena) from the Black Sea

Concentrations of butyltin compounds (BTs) were determined in harbour porpoise (Phocoena phocoena) collected from the Turkish coastal waters of the Black Sea. Total butyltin compounds (∑ BTs) in the liver were in the range of 89–219 ng/g on a wet weight basis. The dibutyltin (DBT) residues were higher than those of tributyltin (TBT), suggesting the degradation of TBT to DBT in the liver and the metabolic capacity comparable to other marine mammals. Any sex difference and age-dependent accumulation of BTs residues were not found in harbour porpoises, but residue levels increased until maturity and then remained constant. When compared with other marine mammals, the present results indicate that the Black Sea is also contaminated with butyltin compounds, but to a lesser degree than coastal waters of developed nations. The biomagnification factor in harbour porpoises was 0.8, which was comparable with pinnipeds and lower than cetaceans. Received: 23 December 1996 / Revised: 15 April 1997 / Accepted: 16 April 1997