Ph. Quevauviller

Organotin stability during storage of marine waters and sediments

SummaryThe stability of organotin compounds in water and sediment samples during storage and pre-treatment is of paramount importance. This study presents experiments with butyltin compounds showing that the storage of filtered natural seawater in the dark at pH 2 in pyrex glass bottles is suitable to preserve the stability of tributyltin (TBT) over 4 months both at 20–25°C and 4°C. The other butyltin compounds (mono- and dibutyltin) are stable at 4°C but display some losses at 25°C. A poor recovery of butyltins in turbid water hampered the assessment of the stability on a quantitative basis: however, it could be demonstrated on a qualitative basis that the butyltin stability is uneasily achieved in water samples with high suspended matter. Finally, wet storage and freezing are found to be suitable to preserve the tributyltin stability in sediments, as well as ovendrying (at 50°C), freeze-drying and air-drying. Mono- and dibutyltin are generally subject to changes during the storage of sediments using the different methods.

Tin and organotin speciation during wastewater and sludge treatment processes

Abstract The speciation of inorganic tin and organotin compounds is studied in raw water samples and in filtered water samples collected along the main steps of the wastewater treatment plant of Bordeaux City (France). Analyses are performed by hydride generation, cryogenic trapping, chromatographic separation and detection by atomic absorption spectrometry. Results show that dissolved inorganic, methylated tin (mono-, di-, trialkylated forms) and butyltin compounds (mono- and dialkylated forms) occur at all stages of the water treatment process. Butyltins were found at low concentration levels which tends to show that the weathering of PVC is a minor phenomenon. High methyltin contents were however found which illustrate the high methylation rate in sewage water; a general removal trend from the water is observed for inorganic and methyl-tin species both in raw water and filtered water samples. Volatilization of tin compounds is observed in the anaerobic fermentation steps of the activated sludge. Possible pathways for transformation of tin (methylation, volatilization) during the wastewater treatment are discussed.

Comparison of Derivatization Methods for the Determination of Butyl- and Phenyl-tin Compounds in Mussels by Gas Chromatography

Commission of the European Communities, DG XII, Standards, Measurements, and TestingProgramme, Rue de la Loi 200, 1049 Brussels, BelgiumTwo different derivatization methods, alkyla-tion with Grignard reagents, and ethylationwith sodium tetraethylborate, were comparedfor the determination of organotin com-pounds, viz. tributyltin, dibutyltin,monobutyltin, triphenyltin, diphenyltin andmonophenyltin, in mussel samples. Tempera-ture, reaction time and concentration ofGrignard reagents were optimized in theformer method; in the latter the effect of pH,concentration of sodium tetraethylborate andreaction time were studied. In the derivatiza-tion with Grignard reagents hexyl, pentyl,propyl, ethyl and methyl were used as alkylGrignard groups. A critical evaluation of thedifferent derivatization methods is presented.© 1997 by John Wiley & Sons, Ltd.

Butyltin distribution in a sediment core from Arcachon harbour (France).

The concentrations of butyltin compounds in water, intertidal sediments and in a sediment core have been measured in the harbour of Arcachon (France) in order to assess the effectiveness of government legislative actions on the use of tributylin (TBT) in marine antifouling paints. The results revealed the occurrence of an increasing TBT gradient from the bottom to the top of the core with a maximum at 15 cm depth, and a slight decrease within the upper 15 cm. It is shown that the TBT levels are still very high in this area and that this compound is not rapidly degraded in sediment as was previously assumed. This leads to the conclusion that even if the regulations have been respected, contamination from resuspended sediments is still likely.

Certification of trimethyl-lead in an urban dust Reference material (CRM 605)

In order to control the quality of trimethyl-lead determination in urban dust, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission organized interlaboratory studies of which the final aim was to certify a Reference Material. This paper describes the preparation of an urban dust reference material (CRM 605), the homogeneity and stability studies, and the analytical work performed for the certification of the trimethyl-lead content (7.9u2005±u20051.2u2009μgu2009kg−1 by mass). Copyright

Survey of butyltin contamination in Portuguese coastal environments.

Butyltin compounds (MBT, DBT and TBT) in intertidal sediments collected in four different Portuguese coastal environments have been measured in order to evaluate the extent of contamination. The sites chosen were the Rias of Aveiro and Faro, and the Sado and Tejo estuaries. These zones were traditional areas for shellfish production in the recent past, but the effects of industrial development have caused a deterioration of the environment. Specific contaminations were derived from the harbour (commercial and/or fisheries) and shipyard activities, resulting in a release of TBT and causing the oyster populations of the above mentioned estuaries to almost disappear. Results presented in this study give a survey of TBT contamination levels found in the four areas. The paper discusses the importance of the pollution in comparison with other European coastal areas.

Certification of total mercury and methyl-mercury in an estuarine sediment, CRM 580

Legislation on methylmercury within the European Union (EU), e.g. in food (national regulations) or water (EC Directives), requires that the determinations are of proven quality; thus implies that they should be carried out under strict quality control (QC). One method of achieving good quality control in chemical analysis is to verify the analytical performance of methods by analysing Certified Reference Materials (CRMs). While CRMs of biological matrices (e.g. fish, mussels) are already available, there was a lack of materials for the QC of sediment analysis. This paper describes the preparation of an estuarine sediment reference material, the homogeneity and stability studies and the analytical work performed for the certification of the contents of total mercury and methylmercury. The results of a group of expert laboratories are discussed and the methods used to certify the mass fractions of total mercury (132u2005±u20053u2005mg kg−1 on a dry mass basis) and methylmercury (75.5u2005±u20053.7u2005μgu2005kg−1 as CH3Hg+ on a dry mass basis) are described. ©u20041998 John Wiley & Sons, Ltd.

Interlaboratory study to improve the quality control of methylmercury determination in sediment

The results are presented of an interlaboratory study on methylmercury (MeHg) in sediment carried out by a group of European laboratories within the framework of a project managed by the EC Standards, Measurements and Testing Programme (formerly BCR). The aim of this exercise was to evaluate the performance of current methods used for MeHg determination in sediment in order to improve the state-of-the-art prior to the certification of a candidate reference material. The paper describes the organization of the interlaboratory study, the preparation of the sediment material used, the techniques evaluated and the results obtained by the participating laboratories. The outcome of the collaborative project showed that certification could be contemplated, providing that certain analytical techniques were optimized, especially with regard to extraction methods.

Conclusions of the workshop

The development of analytical techniques for the determination of chemical species has been one of the fastest growing features of the 90s in analytical chemistry. The need for good quality control of these determinations has led the Measurements and Testing Programme (BCR) to organize several series of interlaboratory studies in the field of speciation analysis over the last five years. The state of the art of speciation analysis was discussed at a first workshop in 1990 (Arcachon, F) and, at this stage, it was deemed necessary to discuss the progress achieved and the trends which should be developed in the near future. A workshop on Trends in Speciation Analysis was therefore held in Rome in February 1994, which allowed recommendations to be made based on round-table discussions. This paper gives a summary of these recommendations in the field of inorganic speciation. Projects currently undertaken in the field of inorganic speciation within the Measurements and Testing Programme are also described. An outline of the programme along with the panel of experts participating in this workshop is given in the appendix.

Projects for the improvement of the quality of chemical speciation analyses in environmental matrices

SummaryThe release of organometallic compounds and other chemical forms of elements in the environment has caused great concern because of their possible high toxicity. To validate the analytical techniques, the Community Bureau of Reference (BCR) has undertaken a series of projects for the improvement of the quality of determinations of chemical species in environmental matrices. The implementation of these projects follows a stepwise approach involving intercomparisons to detect and remove sources of errors in different phases of the analytical methods and the certification of the compounds in various matrices. The current projects deal with the determination of the extractable content of trace metals in soils (single extraction) and sediment (sequential extraction), forms of aluminium in water, elements with different oxidation states (e.g. As, Cr and Se) and organic forms (e.g. methylated forms of As in solution, methyl-mercury in fish, arseno-betaine and -choline in solutions, triethyl- and trimethyl-Pb compounds in solution, and butyltin compounds in sediment).