Seasonal changes in organotin compounds in water and sediment samples from the semi-closed Port of Gdynia.

The effect of seasonal changes on the distribution of organotin compounds (OTC) in the sediments and seawater from the docks of the Port of Gdynia was investigated. Sediment and seawater samples were collected from four industrial docks in February (winter) and June (summer) in 2009. The samples were analyzed for butyltin, phenyltin, octyltin, and tricyclohexyltin (total of 9 OTC derivatives). The fine fraction (<0.063 mm) accumulated the highest concentration of OTC, although it was not the dominant fraction in the sediment samples from the Port of Gdynia. The average concentration of TBT, DBT and MBT in collected samples were as follows: 4400; 2188; 730 ng cation g⁻¹ d.w. (February) 3638; 1590; 474 ng cation g⁻¹ d.w. (June) in the fine sediment samples, 2805; 1266; 485 ng cation g⁻¹ d.w. (February) in <2.00 mm sediment fractions and 118.6; 39.2; 25.3 ng cation L⁻¹ (February) and 46.5; 12.6; 8.2 ng cation L⁻¹ (June) in the water samples. Higher concentrations of butyltin derivatives (BT) were observed in samples collected in February than in those collected in June. Seasonal changes in BT correlate well with changes in the water pH and concentrations of organic matter and can be attributed to sorption/desorption to sediments, photodegradation and biodegradation. Although the Port of Gdynia does not represent the natural features of a marine environment, seasonal variations recorded in the pH values as well as BT, organic carbon and biogenic element concentrations seem to be influenced by temperature and microbial activity.

The content of butyl- and phenyltin derivatives in the sediment from the Port of Gdansk.

Harbor sediments containing large deposits of organotin compounds constitute a potential threat to the marine environment. Samples of harbor sediments were collected twice in the years 2003 and 2005 from the following locations: Ziólkowskiego, Siarkowe, Wislane, Weglowe, Chemików and Paliw Plynnych Quays. The cores of 25cm length sliced into 2- and 5-cm segments were analyzed. After drying and homogenization, samples were split into two granulometric fractions, i.e. <2.00 and <0.063mm. The dominant fraction in whole sediment, i.e. fraction grain diameter <2.00mm, was sand (grain diameter 2.00-0.063mm). However, the highest concentrations of butyltin (BT) and phenyltin (PT) compounds were found in the fine sediment fraction. The mean values of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) in the analyzed samples in the <2.00mm fraction were 2144.9, 434.7 and 148.1ngSng(-1)d.w., respectively, while the corresponding mean values in the <0.063mm fraction were 6556.4, 1593.7 and 450.0ngSng(-1)d.w. The mean concentrations of monophenyltin (MPhT) have been estimated at 29.0 and 49.9ngSng(-1)d.w. for the <2.00 and <0.063mm fraction sizes, respectively. The estimated content levels of diphenyltin (DPhT) and triphenyltin (TPhT) were in most cases below the detection limit of the applied method. The sediment cores collected from the locations characterized by high industrialization and intense exploitation (Wislane, Weglowe Quays) contained the highest concentrations of BT and PT.

Optimisation of pressurised liquid extraction for elimination of sulphur interferences during determination of organotin compounds in sulphur-rich sediments by gas chromatography with flame photometric detection.

A simple method for species-selective analysis of organotin compounds (OTCs) (butyl and phenyl) in sediments was developed. The sample preparation procedure was specifically optimised for sulphur-rich sediments to eliminate interferences from elemental sulphur and organosulphur compounds. Tin species were extracted from sediment samples using pressurised liquid extraction technique (PLE), ethylated - with simultaneous extraction to isooctane - in aqueous phase with sodium tetraethylborate (NaBEt(4)) and separated/detected by gas chromatography with flame photometric detection (GC-FPD). PLE operational variables (extraction temperature and pressure, solvent composition and number of static extraction steps) and extract handling routine were fine-tuned to minimise the amount of extracted interferents while keeping OTCs recovery at an acceptable level. Best results were obtained after extraction of sediment samples with methanol/water (75% v/v methanol) solution of acetic acid/sodium acetate with tropolone addition (0.6 g l(-1)). Derivatisation of low temperature, high-pressure (50 degrees C, 13.8 MPa) extracts gives isooctane extracts which are clean enough to be directly analysed by GC-FPD without any further cleanup. Interferences from elemental sulphur were completely eliminated while concentrations of other interferents were reduced to the level not impairing quantitation of OTCs under the study. No negative effects in terms of chromatographic column deterioration were observed after repeated injections of such extracts. Two certified reference materials, BCR646 and PACS-2, were analysed to assess performance of the method. Recoveries of all OTCs under the study, except MBT, were in the range of 91-114%. MBT extraction efficiency was low (34-47%) therefore the method is unsuitable for precise determinations of this compound.