Effect of the orientation and fluid flow on the accumulation of organotin compounds to Chemcatcher passive samplers

Abstract

Monitoring of harmful substances in an aquatic environment is based on spot sampling which is the only sampling technique accepted by environmental authorities in the European Union. Still the implementation of the European Union Water Framework Directive (WFD) requires novel sampling tools for monitoring priority pollutants since their concentrations in natural waters can often remain below the limit of detection when using the conventional spot sampling method. However, this does not necessarily mean that the pollutant is not present in the aquatic environment. Many chemicals that are considered to be harmful are bioaccumulative and can affect, e.g., reproduction of aquatic organisms even at very low concentration levels. Also the timing is crucial since with spot sampling the pulse of harmful substances can easily be missed. Passive samplers collect the compounds for a certain amount of time which allows the concentrations in the sampler to rise to the measurable level where they are easy to detect. Organotin compounds (OTCs) have been widely used as plastic stabilizers and antifouling agents in ship paints and in many industrial processes. Among the OTCs, tributyltin is listed as a WFD priority substance. In this study a small-scale flow simulation around the Chemcatcher passive sampler was performed to visualize the flow streamlines in the vicinity of the sampler and to study the pressure experienced by the receiving phase in different sampler positions. With laboratory experiments the sampling rates for each OTC were determined and the effect of the flow velocity and sampler orientation on the accumulation of OTCs is discussed. The pressure changes were observed on the surface of the receiving phase in simulations with varying sampler orientations. Despite that, the laboratory experiments discovered no difference in the accumulation of compounds when varying the sampler orientation. The concentrations of OTCs in the surrounding water calculated from the passive sampling results were equivalent to the spot sampling ones. Hence, the Chemcatcher passive sampler provides a practical tool for the implementation of WFD.

Pharmaceuticals and pesticides archived on polar passive sampling devices can be stable for up to 6 years

“…Some of this variation may result from differences in orientation between 2 passive sampling device cages and/or o-DGT samplers within the same cage (the 8 o-DGT used in the present study were deployed in 2 side-byside cages). This may cause certain samplers to experience differing flow regimes [20] or lead to preferential fouling of certain o-DGT samplers compared with others (J.K. Challis et al, University of Manitoba, Winnipeg, MB, Canada, unpublished data). It should be noted that these o-DGT were severely fouled after the 3-wk deployment (images in Challis et al [16]).…”

“…Average changes in analyte mass after 368 d of storage was 14%. This may cause certain samplers to experience differing flow regimes [20] or lead to preferential fouling of certain o-DGT samplers compared with others (J.K. Challis et al, University of Manitoba, Winnipeg, MB, Canada, unpublished data). The only statistically significant results were observed for atrazine, which showed a mass increase after 368 d and a significantly positive slope (p ¼ 0.002, n ¼ 4 for linear regression).…”

Overview of the Chemcatcher® for the passive sampling of various pollutants in aquatic environments Part B: Field handling and environmental applications for the monitoring of pollutants and their biological effects

“…Biomonitoring and bioassay applications (i.e., Chemcatcher s extracts for bioassays, ecotoxicological studies, comparison with biomonitoring). Ahkola et al [5] investigated in the laboratory the effect of Chemcatcher s orientation (parallel, perpendicular and 45°angle toward water flow) on the accumulation of organotin compounds.…”

Monitoring and Modelling of Butyltin Compounds in Finnish Inland Lake

“…The samplers accumulate dissolved fraction of the chemical which, after the deployment time period, is extracted from the sampler. TWA concentrations of dissolved BTCs during the two weeks sampling period were calculated with using sampling rates determined in Ahkola et al (2015Ahkola et al ( , 2016. Method detection limit (MDL) was calculated from the analytical limit of detection (ng sampler -1 ) after 14 days deployment (Table 1).…”

“…Monobutyltin (MBT) and DBT have been used as PVC stabilizers in packaging materials from which they can leach to foodstuff and beverages (Takahashi et al 1999, Hoch 2001. Despite the restrictions these substances are still found in Finnish inland waters where they are released for example via wastewater treatment plants (WWTP) (Mannio 2011, Vieno 2014, Ahkola et al 2015.…”