Research of harmful substances in aquatic environments using new measuring and evaluation methods (PASMA)

Project background and aims

The primary aim of PASMA project is to test research methods of harmful substances. This project focuses on the definition of organic tin compounds. The accuracy in defining organic tin compounds is improved by validating the isotope dilution method for the first time in Finland. This method enables a more reliable and sensitive definition. Passive sampling techniques in which the Chemcatcher sampler (photo) is used are developed in this project. This project also aims to increase the availability of the components used in the Chemcatcher sampler. In addition an incubating base for the samplers that can be used in inland waters is being developed. The samplers will be tested in both the laboratory and on the field.

Chemcatcher sampler for observation of organic tin compounds in Lake Päijänne. The middle of the sampler contains a semi permeable membrane under which there is an Empore sheet to which the tin compounds will attach. Photo: Kirsti Krogerus

The results from this project as well as from the parallel project sponsored by the Nessling foundation are used in the development of modeling tools. In order to conduct the evaluation of drifting and distributing of organic tin compounds a process description will be devised and necessary changes made to the code of a current and water quality model COHERENS.

The responsibilities of the Finnish Environment Institute in the PASMA project

In the PASMA project SYKE is focusing mainly on the development of passive samplers and modeling tools. SYKE is in charge of the measuring data and arrangements of the current and sedimentation measurements and passive samplers. Additionally, SYKE manages the implementation of current pool tests.

Sediment samplers, in which suspended solids are gathered for organic tin analyses. Photo: Kirsti Krogerus

An Acoustic Doppler Current Profiler installed in northern Lake Päijänne to measure water movements in the hole water mass above the meter. Photo: Janne Juntunen

A 3-dimensional water quality and current model was created for our research target Poronselkä, located in northern Lake Päijänne. The COHERENS model, which has thus far been used to describe current and temperature and the distribution of nutrients and suspended solids, is used for calculations. Organic tin compounds will be added to the calculation.

In Finland lake sediments have been contaminated by organic tin compounds in all water management areas except Lapland. These compounds have been found in several places including Lake Jyväsjärvi and Lake Päijänne.

Trisubstitated organic tin compounds like TBT and TPht (tributylitin, triphenyltin) have been used since the 1960's as biocides in for example the wood processing industry. Mono- and disubstituted compounds like MBT, DBT and DOT (monobutyltin, dibutyltin ja dioktyltin) have been used extensively and are still used in industry processes and products, for example as catalysts and as a plastic additive. They can also occur as a result of degradation of trisubstitated compounds. Organic tin compounds decompose in the environment both chemically and biologically but in cold environment and without oxygen decomposition is extremely slow.

Further information

Person in charge in SYKE:
Senior Research Scientist Kirsti Krogerus, Finnish Environment Institute (SYKE),

Published 2013-04-24 at 15:11, updated 2013-09-16 at 12:09