Analysis of tributyltin in estuarine sediments and oyster tissue,Crassostrea virginica

An analytical method to determine tributyltin (TBT) in oyster tissue, Crassostrea virginica, and estuarine sediments is described. Recoveries of TBT from oysters range from 86 to 102% when samples are fortified at concentrations ranging from 22 to 890 μg kg^?1 (wet weight); recoveries from sediment range from 92 to 105% for samples fortified from 20 to 500 μg kg^?1 (dry weight). Feral oysters and natural sediments were analysed and shown to be contaminated with TBT. Oysters collected near a marina contained concentrations as high as 1.5 mg kg^?1 (wet weight).     

Occurrence of butyltin compounds in marine sediments and bivalves from three harbour areas (Saigon,Da Nang and Hai Phong) in Vietnam

A survey of organotin compounds comprising tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) in sediment and clam (Meretrix meretrix) was undertaken in Vietnam in 2003. Samples were collected from dry docks and cargo harbours in Ho Chi Minh (south), Da Nang (centre) and Hai Phong (north) cities. Measurable amounts of TBT, DBT and MBT were found in all samples. The total concentration of the butyltin compounds (ΣBTs) in sediment from shipyards and vessel repair yards (Nam Trieu, Song Cam, Lach Tray and Ba Son) were always higher than those measured in cargo ports (Hai Phong, Da Nang, and Sai Gon). The highest ΣBTs concentration (as tin: 122 ng g^?1 dry wt) was found in the sediment from Song Cam station, where seven shipyards are located. The lowest concentrations of ΣBTs occurred in sediments from the Da Nang and Hai Phong cargo ports (as tin: 21–22 ng g^?1 dry wt). This implies that the major source of BTs in the marine environment in Vietnam is from the shipbuilding activities. The ratio of TBT to Σ(MBT + DBT) in sediment was 0.67 ± 0.03 for all the sampling sites, indicating the recent use of TBT in Vietnam. For the clam (M. meretrix), the concentration of ΣBTs (as tin) varied in the range 11.2–60.1 ng g^?1 wet wt. There was a good correlation (R² = 0.85) between total organic matter‐normalized ΣBTs in sediment and hexane‐extractable organic matter‐normalized ΣBTs in clam soft tissue. The mean biota–sediment accumulation factors (organic carbon/lipid) for MBT, DBT and TBT in clam's soft tissue were found to be 1.83 ± 0.66, 1.44 ± 0.23 and 1.16 ± 0.47 respectively, indicating that sediment‐bound BTs might be an important source of contamination for the clam. Copyright © 2005 John Wiley & Sons, Ltd.     

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.     

Search for triorganotins along the Mar del Plata (Argentina) marine coast: finding of tributyltin in egg capsules of a snail Adelomelon brasiliana (Lamarck, 1822) population showing imposex effects

Cases of imposex were clearly identified in Adelomelon brasiliana living in the Mar del Plata (Argentina) coastal area; percentages as high as 50.0% were determined among the samples studied. These were the first reported cases of ocurrence of imposex in this type of gastropod. Since this is one of the known tributyltin (TBTs) effects, and no previous reports of determination of TBTs in gastropods eggs were found, methods were developed for the speciation and quantitative determination of organotins in A. brasiliana egg capsules. Determination of organotins in samples collected in the Mar del Plata area showed contents of tributyltin chloride (TBT) as high as 400 ng l^?1 in water and 6.50 µg g^?1 in sediments of areas of intensive boat traffic. The results showed the presence of TBT in the egg capsules of A. brasiliana at three different instars (range 0.264–1.86 µg per egg). As far as we know, this is the first report of the finding of TBT in gastropod egg capsules. Copyright © 2004 John Wiley & Sons, Ltd.     

Determination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in food and beverages

The determination of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) in food and beverages sold in Turkey was carried out using liquid chromatography–tandem mass spectrometry (LC-MS/MS). A total of 123 samples of selected food and beverages such as fish, meat, offal, egg, cracker, chips, cake, chocolate, vegetable, milk and juice were examined. The highest PFOA concentrations were determined in cow meat (5.15 ng g^?1), cow kidney (5.65 ng g^?1), cow spleen (5.06 ng g^?1) and chicken liver (5.02 ng g^?1). The highest PFOS levels were found in horse mackerel (52.43 ng g^?1), pike-perch (45.87 ng g^?1), sardine (42.83 ng g^?1) and black cod (41.33 ng g^?1). Fish was found to be major source of the PFOS intake, while meat and offal were found to be major sources of the PFOA intake.     

Spatial and seasonal behaviour of organotin compounds in protected subtropical estuarine ecosystems in Okinawa,Japan

The spatial and temporal behaviours of the organotin compounds (OTCs) (butyl- and phenyltin) were investigated in the Manko and Okukubi protected estuarine ecosystems on Okinawa Island, Japan from February to October 2006. Butyltin compounds (BTCs) were frequently detected in all seasons, while phenyltin (PhTs) were found in winter and early spring. In Manko estuary, the total mean concentrations of BTCs and PhTs were 22.78?±?30.85, (mean?±?SD, n?=?53) and 0.08?±?0.27?ng(Sn)?L^?1, respectively. In Okukubi estuary, BTCs and PhTs were 12.58?±?23.96 and 0.47?±?1.67 (n?=?55) ng(Sn)?L^?1, respectively. The Manko sediments can be classified as lightly contaminated, while the Okukubi sediments were uncontaminated with tributyltin (TBT). The mean levels of TBT shown in Manko estuary exceeded the threshold level and represent an ecotoxicological risk to sensitive aquatic life. Generally, the present study reports the occurrence and continuous input of OTCs in the protected estuaries, even 16 years after legal restriction of TBT usage in coastal waters was implemented by the Japanese Environmental Authorities.     

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.     

Emission to air of volatile organotins from tributyltin‐contaminated harbour sediments

An analytical method for determining the presence in air of volatile forms (e.g. chlorides) of tributyltin (TBT) and that of methylbutyltins Me _nBu_(4?n)Sn (n = 1–3) was developed and used to establish whether dredged harbour sediments contaminated with TBT served as sources of air pollution with respect to organotin compounds. The method was based on active sampling of the air being analysed and sorption of analytes onto Poropak‐N. Sorbed methylbutyltins were extracted with dichloromethane and analysed by gas chromatography using flame photometric detection. Other butyltins were converted into butyltin hydrides prior to analysis by gas chromatography. It was shown that TBT‐contaminated sediments from Marsamxett Harbour, Malta, placed in 0.5 l chambers through which air was displaced by continuous pumping for 11 days released mainly methylbutyltins, with concentrations (as tin) reaching maximum 48 h mean values of 8.7 (Me₃BuSn), 22.1 (Me₂Bu₂Sn) and 93.0 ng m^?3(MeBu₃Sn) being measured. Other volatile forms of TBT, dibutyltin and monobutyltin were detected in the headspace air, but very infrequently and at much lower tin concentrations (<2 ng m^?3). It was also shown that methylbutyltins dissolved in sea‐water ([Sn] = 0.2 to 400 ng l^?1) were very difficult to exsolve from this medium, even on prolonged evaporation of the solutions using mechanical agitation and active ventilation. The results suggest that emission of methylbutyltins from contaminated sediments probably occurs only from the surface of the material. The environmental implications of these findings in the management of TBT‐polluted harbour sediments are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Tributyltin speciation in aquatic matrices by CGC-FPD and CGC-MS confirmation

An analytical procedure for the determination of tributyltin (TBT) in seawater, sediments and biota is described. Extraction of TBT as chloride is achieved by hydrochloric acid treatment followed by a liquid extraction using a modified solvent with a metal coordinating ligand, and a Grignard derivatization (CH₃MgCl). The organotin fraction was isolated from the derivatized extract by column chromatography. The final determination was accomplished by on-column capillary gas chromatography (CGC) coupled to a flame photometric detector (FPD) and mass spectrometry (MS) confirmation. The relative detection limits of the analytical procedure were dependent of the environmental compartment, 0.5 ng 1^–1 (as TBT) for seawater, and 0.1 ng g^–1 and 0.4 ng g^–1 for sediments and biota, respectively. The TBT recovery of fortified samples was in the range of 90% for water and biota, and of 60% in case of sediments. The reproducibility (RSD) of the whole procedure for three independent replicates was around 15%.     

Simultaneous butyltin determinations in the microlayer,water column and sediment of a northern Chesapeake Bay marina and receiving system

Butyltins were determined in the microlayer, water column and sediment of a northern Chesapeake Bay marina and its receiving system. Concentrations of the toxicant species tributyltin (TBT) ranged from 60 to 4130 ng dm⁻³ in the microlayer, from 34 to 367 ng dm⁻³ in the water column and from <0.05 to 1.4 m̈g g⁻¹ (dry weight) in sediment. TBT concentrations in all three environmental compartments were higher in the marinas than in the receiving system. Concentrations of TBT in the microlayer and water column of the study area were potentially toxic to sensitive aquatic biota. The microlayer appears to be depleted in dibutyltin relative to tributyltin compared to both water column and sediment.     

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.     

Determination of tributyltin oxide in coastal marine sediments and mussels by electrothermal atomic absorption spectrometry

We have devised a new method for bis(tributyltin)oxide (TBTO) determination in marine sediments and mussels. This technique involves an n-hexane/methylene chloride mixture extraction and extract purification with a sodium hydroxide wash in order to eliminate interfering compounds. TBTO is then extracted again by nitric acid and converted into an inorganic tin species; the analysis has been effected using Zeeman graphite furnace-atomic absorption spectrophotometry. The method detection limit for the matrices examined is 0.004 μg TBTO g^?1 (wet weight) and is sufficient for the analysis in real samples. The percentage recovery of TBTO from sediments and mussels samples is higher than 85% and 95% respectively. This method has been applied to TBTO level determination in sediments and mussels (Mytilus galloprovincialis) sampled in the harbour area in Taranto, where mussel culture activities are much developed; the TBTO levels obtained in sediments and mussels were in the range 15-47 ng g^?1 (wet weight) and 11-30 ng g^?1 (wet weight) respectively. Such values are comparable with those found in other harbour areas in the Mediterranean Sea.     

Contamination of outdoor settled dust by butyltins in Malta

The presence of compounds of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) was determined in outdoor settled dust collected from several sites on the island of Malta, mainly from flat rooftops of school buildings. The dust was separated into three size fractions with diameters (µm) > 250, 125–250 and < 125, and the two finer fractions were analysed for butyltins using extraction with glacial acetic acid followed by derivatization/solvent extraction with sodium tetraethylborate in the presence of iso‐octane and quantitation by gas chromatography with flame photometric detection. The presence of TBT, DBT and MBT was established in most of the samples and TBT concentrations varied from non‐detectable (<5 ng Sn g^?1) to highs of 15.5 and 18.7 µg Sn g^?1 in Senglea and Marsaxlokk. TBT was generally found at concentrations significantly higher than reported hitherto in house dust collected from European homes. The geographical distribution of total organotins in both dust fractions suggests that TBT originates mainly from antifouling marine paint residues which contaminate the urban environment when ships' hulls are sand‐ or hydro‐blasted during maintenance and repair at the drydocks facility in Grand Harbour. Other significant sources of TBT are located at Marsaxlokk fishing port and Wied i?‐?urrieq creek, both hosting sizeable communities of fishermen and leisure boating. The data also suggest that the municipal solid waste landfill at Maghtab is an inland source of butyltins. We suggest that dust containing harmful butyltins could possibly be ingested to expose humans to a risk which is probably of concern especially for young children living close to the hotspots of contamination. Copyright © 2007 John Wiley & Sons, Ltd.     

Determination of tributyltin in marine sediment and waters by pressurised solvent extraction and liquid chromatography-tandem mass spectrometry

In this study, tributyltin (TBT) was extracted from marine sediment matrix with the use of pressurised solvent extraction (PSE), which uses high-temperature and -pressure conditions to increase extraction efficiency. The analyte was chromatographically resolved using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system with a pentafluorophenyl (PFP) column and a methanol/aqueous formic acid mobile phase gradient, and was detected by MS/MS as product fragments after collisionally induced dissociation (CID) of the cationic parent molecule. This study represents the first application of PSE extraction combined with LC-MS/MS analysis for the determination of TBT in sediments. The method has been validated according to the International Organisation for Standardisation (ISO) 17025:2001 and affords automated extraction of sediment samples with high-sensitivity analysis. The full method limit of detection was established as 1.25 ng Sn g^?1 with an instrument detection limit of 0.01 ng Sn g^?1. The chromatographic procedure may also be applied for the direct analysis of water matrices without the need for sample manipulation, and therefore represents a combined analytical approach for the monitoring of TBT contamination in marine or estuarine ecosystems.     

The idea of simultaneous batch in-situ extraction and arsenic and antimony hydride generation atomic absorption spectrometry determination directly in the solid (tsunami and lake sediments) samples

The article presents the application of in-situ extraction from a solid sample in order to determine metalloids: arsenic and antimony. The reaction vessel, in which hydride generation followed the extraction, was connected with the atomic absorption spectrometer (AAS) in a fast sequential mode. Deionised water, phosphatic buffer (pH?=?6) and hydrochloric acid (2?mol?L^?1) were used as the extractants to determine the concentration of metalloids in the following fractions: easily (water) leachable, exchangeable, and acid leachable. Two different types of sediments were used while developing the application: lake bottom sediments and tsunami deposits. Both types of the sediments samples (5–20?mg) were placed directly in the reaction vessel and after in-situ extraction the determination of the metalloids was conducted, what allowed to assess concentration of arsenic and antimony during single analysis. The results obtained from the analyses of both sediments types were compared with the results from traditional off-line extraction. As a result a good correspondence with both hydrochloric acid and phosphatic buffer was found. The methodology of solid samples analysis was developed with detection limits of 50?ng?g^?1 (for As) and 30?ng?g^?1 (for Sb) for 10?mg of a solid sample.     

Single robust RP-HPLC analytical method for quantification of curcuminoids in commercial turmeric products,Ayurvedic medicines,and nanovesicular systems

A single robust reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated as per International Conference on Harmonization guidelines for the accurate quantification of curcuminoids in commercial turmeric products, Ayurvedic medicines, and nanovesicular systems. The proposed chromatographic method was found to be specific, linear (r²?≥?0.999), precise at intra- and inter-day levels (percentage relative standard deviation <2.0%), accurate (percentage recovery 99.14–102.29%), and robust. The limits of detection and quantification were found to be 7.40 and 24.70?ng?mL^?1 for curcumin, 9.24 and 30.80?ng?mL^?1 for demethoxycurcumin, and 6.48 and 21.61?ng?mL^?1 for bisdemethoxycurcumin, respectively. Among different commercial turmeric products and Ayurvedic medicines tested, the contents of curcumin (3.54?±?0.06–25.8?±?0.08?mg?g^?1), demethoxycurcumin (1.28?±?0.02–9.97?±?0.03?mg?g^?1), and bisdemethoxycurcumin (0.50?±?0.01–5.97?±?0.01?mg?g^?1) varied significantly. The developed method was effectively applied to the determination of encapsulation efficiency of curcuminoids (ranged between 84.33?±?3.50 and 96.59?±?2.53%) in the nanovesicular systems. In conclusion, the reported method is suitable for the analysis of curcuminoids in a wide variety of turmeric products and used for the quality control of products that contain curcuminoids.     

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.     

Preliminary evidence for in vitro methylation of tributyltin in a marine sediment

Recent reports from our laboratory on the occurrence of methylbutyltins in marine sediments and seawater suggest that these compounds are formed in the environment by the methylation of both tributyltin (TBT) and that­of its degradation products, i.e. dibutyltin and monobutyltin, to give Me_nBu_(4?n)Sn for which n = 1, 2 and 3 respectively. We investigated the possibility of inducing methylation of TBT in seawater–sediment mixtures in experiments carried out in vitro using environmental materials collected from a yacht marina in Msida, Malta. Three water–sediment mixtures, which were shown to contain TBT, dibutyltin and monobutyltin but no other organotins, were spiked with tributyltin chloride (90 mg in 100 ml sea‐water/100 ml sediment); to one mixture was added sodium acetate and to another methanol, to act as possible additional carbon sources, and all mixtures were allowed to stand at 25 °C in stoppered clear‐glass bottles in diffused light for a maximum of 315 days. Speciation and quantification of organotins was performed using aqueous phase boroethylation with simultaneous solvent extraction followed by gas chromatography with flame photometric detection. The atmosphere inside the bottles quickly became reducing with abundant presence of H₂S, and after an induction period of about 112 days, and only in the reaction mixture containing methanol, methyltributyltin (MeBu₃Sn) was observed in both sediment (maximum concentration 0.87 µg_Sn g^?1) and overlying water (maximum concentration 6.0 µg_Sn l^?1). The minimum conversion yield of TBT into MeBu₃Sn was estimated to be 0.3%. MeBu₃Sn has a significantly lower affinity for sediment than TBT and, therefore, is more mobile in the marine environment, possibly also migrating into the atmosphere to generate a hitherto unsuspected flux of organotin into that phase. Copyright © 2001 John Wiley & Sons, Ltd.     

Synthesis of derivatives and production of antiserum for class specific detection of pyrethroids by indirect ELISA

Two series of haptens including 3-phenoxybenzoic acid (PBA) and 3-(2-chloro-3, 3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclo-propanecarboxylic acid (CF₃MPA) were used to prepare immunogens through attachment of 4-C or 6-C handles. Class selective antibodies were produced by immunising rabbits. Ab502 showed the highest reactivity towards tau-fluvalinate (IC₅₀ 1.3 ng mL^?1), λ-cyhalothrin (IC₅₀ 2.3 ng mL^?1), cyfluthrin (IC₅₀ 2.2 ng mL^?1) and fenpropathrin (IC₅₀ 18.5 ng mL^?1) among the antibodies in a competitive ELISA. The effects of methanol, pH and salt concentration were optimised for maximum efficiency of the ELISA (Enzyme-Linked ImmunoSorbent Assay). Ab502 (1:80000)/2-OVA-1(0.2 µg mL^?1) was chosen for ELISA optimisation. Finally, 0.05 M phosphate buffered saline (PBS) at pH 6.5 containing 30% methanol (v/v) was used to dilute the standards. Target analytes in honey samples were extracted with ethyl acetate by sonication. The samples were spiked with three different concentrations of each compound (tau-fluvalinate, 0.5 ng g^?1, 3 ng g^?1, 12 ng g^?1; λ-cyhalothrin and cyfluthrin 1 ng g^?1, 5 ng g^?1, 65 ng g^?1). The recoveries were 36–59% at the lowest spiking concentration and 61–81% at the higher concentration. This assay might be useful to screen pyrethroid residues in honey or other matrix.     

Organotin contamination,imposex and androgen/oestrogen ratios in natural populations of Nassarius reticulatus along a ship density gradient

Levels of organotin body burden (expressed as tin), imposex and steroid hormones (testosterone, 17β‐oestradiol, testosterone glucuronide and sulfate conjugates) were investigated in natural populations of Nassarius reticulatus in the Ria de Aveiro (northwest Portugal) between 1997 and 1999. The tributyltin (TBT) whole body burden (b.b.) of females presented increasing gradients from the adjacent open coast (16–26 ng g^?1 dry weight (d.w.)) towards the ports inside the Ria de Aveiro (195–272 ng g^?1 d.w.). Triphenyltin b.b. was only detected at the most polluted port (22 ng g^?1 d.w.). Imposex also presented increasing values from the adjacent coast (vas deferens sequence index (VDSI): 0.0–0.5; relative penis length index (RPLI): 0.0–2.4; penis length index (PLI): 0.0–0.3 mm; percentage of affected females (%I): 0–30) towards the ports (VDSI: 3.8–4.8; RPLI: 51–80; PLI: 6.7–10.8 mm; %I: 100). The testosterone levels in females without imposex were always lower than in females with imposex, and the ratio of testosterone/17β‐oestradiol in females tended to increase with increasing imposex and organotin contamination. In spite of the large difference in the female testosterone and 17β‐oestradiol levels between summer and winter, related to the reproductive cycle, the spatial trend of the testosterone/17β‐oestradiol ratio was remarkably similar in shape and values in the two seasons. Imposex was significantly correlated with the TBT b.b. and the testosterone/17β‐oestradiol ratio in females. The testosterone conjugate levels did not show any clear pattern with the increasing values of imposex and TBT contamination. Copyright © 2005 John Wiley & Sons, Ltd.