Monitoring and Modelling of Butyltin Compounds in Finnish Inland Lake

Butyltin compounds (BTCs) in surface waters is seldom studied due to their low concentrations and limitations of analytical techniques. In this study we measured total concentration of BTCs with grab water sampling, dissolved concentration with passive samplers and particle bound fraction with sedimentation traps in Finnish inland lake. The sampling was conducted from May to September during two study years. The differences between sampling techniques and the concentrations were obvious. E.g. tributyltin (TBT) was detected only in 4-24 % of the grab samples when the detection with passive samplers was 93% and with sedimentation traps 50%. The dissolved BTC concentrations measured with grab and passive sampling suggested hydrological differences between the study years. This was confirmed with flow velocity measurements. However, the annual difference was not observed in BTC concentrations of settled particle.The extreme value analysis suggested that grab sampling and sedimentation trap sampling results contain more extreme peak values than passive sampling. This indicates that BTCs are present in surface water in trace concentrations despite they are not detected with all the sampling techniques. The assumption that WWTP, located in the study area, was the source of BTCs was not valid as elevated BTC concentrations were detected also at the reference site, located upstream of WWTP. Computational modelling and back tracking simulations also supported the concept that WWTP cannot be the only source but BTCs can come even from upstream of the sampling area where there is e.g. wood processing industry.

Distribution of butyltin compounds in the coastal environment of the Bahía Blanca estuary, Argentina

This study evaluates for the first time the distribution and accumulation of butyltin compounds (BTs) in different compartments as seawater, sediments, suspended particulate matter (SPM) and mussels (Brachidontes rodriguezii) in the Bahía Blanca estuary. The samples were collected from six sampling sites with different anthropogenic impact. A better visualization and interpretation of data were achieved using chemometric tools (Tucker4 model), which made it possible to reveal the main relationships between the variables. This analysis showed the presence of BTs in all environmental compartments along the estuary, even in sites with low human intervention. The relationships found between BTs levels, seasons and environmental matrices show the importance of biological processes such as phytoplankton blooms and remobilization of sediments (by tidal dynamics and/or periodic dredging) in the BTs distribution and degradation. In addition, partition coefficients showed that mussels mainly bioaccumulate tributyltin through sediment, water and, to a lesser extent, from SPM.

Accumulation of organotin compounds on mangroves in coastal ecosystems

To elucidate the details of both the current status of contamination and the accumulation of organotin compounds (OTs) in mangroves in coastal ecosystems, we determined the concentrations of butyltin compounds (BTs) and phenyltin compounds (PTs) in sediment and mangrove leaves collected from mangrove forests in Merambong and Tinggi Island, Malaysia. Butyltins were detected in all sediment samples collected from both regions, whereas PTs were not detected. The levels of tributyltin (TBT) compounds in the sediment samples were lower than those from previous studies conducted in Malaysia and at other sites in South-east Asia. In both Merambong and Tinggi Island, the average proportions of dibutyltin (DBT) and monobutyltin (MBT), which are degradation products of TBT, were ~70%. This result suggests that the input of TBT has decreased in Malaysia. The proportions of DBT and MBT in the sediment from Merambong were higher than those from Tinggi Island. The concentrations of TBT in mangrove leaves from Tinggi Island were significantly higher than those from Merambong. MBT was the most dominant type among the BTs in mangrove leaves from both Merambong and Tinggi Island. The ratios of the BTs burden in mangrove leaves to the BTs concentration in sediment from Merambong and Tinggi Island averaged 3.1 and 6.2, respectively. Among the values of BTs, the MBT values were found to be the highest in both regions.