Organotin compounds in surface sediments of the Southern Baltic coastal zone: a study on the main factors for their accumulation and degradation

Abstract Sediment samples were collected in the Gulf of Gdańsk, and the Vistula and Szczecin Lagoons—all located in the coastal zone of the Southern Baltic Sea—just after the total ban on using harmful organotins in antifouling paints on ships came into force, to assess their butyltin and phenyltin contamination extent. Altogether, 26 sampling stations were chosen to account for different potential exposure to organotin pollution and environmental conditions: from shallow and well-oxygenated waters, shipping routes and river mouths, to deep and anoxic sites. Additionally, the organic carbon content, pigment content, and grain size of all the sediment samples were determined, and some parameters of the nearbottom water (oxygen content, salinity, temperature) were measured as well. Total concentrations of butyltin compounds ranged between 2 and 182 ng Sn g−1 d.w., whereas phenyltins were below the detection limit. Sediments from the Gulf of Gdańsk and Vistula Lagoon were found moderately contaminated with tributyltin, whereas those from the Szczecin Lagoon were ranked as highly contaminated. Butyltin degradation indices prove a recent tributyltin input into the sediments adjacent to sites used for dumping for dredged harbor materials and for anchorage in the Gulf of Gdańsk (where two big international ports are located), and into those collected in the Szczecin Lagoon. Essential factors affecting the degradation and distribution of organotins, based on significant correlations between butyltins and environmental variables, were found in the study area

Effect of Temperature and Mass Concentration of SiO₂ Nanoparticles on Electrical Conductivity of Ethylene Glycol

Electrical conductivity of nanofluids is one of the physical properties which are intensively investigated by researchers. This paper brings contributions in this research area. Electrical conductivity of nanofluids containing various mass concentration of silicon dioxide (SiO₂) nanoparticles suspended in ethylene glycol (EG) were investigated at various ambient temperatures. Temperature was changed from 20°C to 60°C with 10°C step. Measurements were performed with digital conductivity meter (MultiLine 3410, WTW GmBH, Weilheim, Germany) and it was observed that increase in mass concentration of SiO₂ nanoparticles cause increase in electrical conductivity. The same dependence was observed between temperature and electrical conductivity

Electrical Conductivity of Ethylene Glycol Based Nanofluids with Different Types of Thulium Oxide Nanoparticles

The paper presents experimental investigation on electrical conductivity of thulium oxides-ethylene glycol (Tm₂O₃-EG) nanofluids based on nanoparticles with three different sizes, and prepared in different conditions. Nanofluids were prepared with two-step method with use of the nanoparticles obtained by precipitation method. Measurements were conducted at constant temperature 293.15 K for various mass concentrations from 0% to 20% with 5% step. The electrical conductivity was measured using conductivity meter MultiLine 3410 (WTW GmBH, Weilheim, Germany) and temperature was stabilized in a water bath MLL 547 (AJL Electronic, Cracow, Poland). The results indicate that increase in mass concentration of nanoparticles in base fluid causes increase in electrical conductivity of Tm₂O₃-EG nanofluids. The enhancement in electrical conductivity of nanosuspensions of thulium oxide is dependent on particle size

Dynamic Viscosity of Aluminum Oxide-Ethylene Glycol (Al₂O₃-EG) Nanofluids

The paper presents the results of measurements of rheological properties of ethylene glycol (EG) based aluminum oxide (Al₂O₃) nanofluids. The nanofluids have been produced by two-step method with the use of commercially available nanoparticles. Dynamic viscosity curves and dependence of viscosity on temperature for these materials have been measured. It has shown that with higher concentration of nanoparticles in the suspension, these nanofluids exhibit the non-Newtonian flow and it can be considered as shear-thinning liquids. The effect of temperature on the dynamic viscosity in Al₂O₃-EG nanofluids can be modelled with the use of Vogel-Fulcher-Tammann expression

An Experimental Investigation of Electrical Conductivity of Y₃Al₅O₁₂-Ethylene Glycol Nanofluids

Paper presents results of experimental studies of electrical conductivity of yttrium aluminum garnet-ethylene glycol (Y₃Al₅O₁₂-EG, YAG-EG) nanofluids, which were prepared by dispersing commercially available nanoparticles manufactured by Baikowski (Annecy, France, ID LOT: 18513) in ethylene glycol. The electrical conductivity was measured using conductivity meter MultiLine 3410 (WTW GmBH, Weilheim, Germany). In turn the temperature was stabilized in a water bath MLL 547 (AJL Electronic, Cracow, Poland). The electrical conductivity of YAG-EG nanofluids with various mass concentrations form 5% to 20% was investigated at different ambient temperatures. The experimental data indicate that changing volume fraction of YAG nanoparticles in ethylene glycol cause change of electrical conductivity of nanofluid. It was also presented that electrical conductivity depends on temperature of materials

Electrical Properties of Aluminum Oxide-Ethylene Glycol (Al₂O₃-EG) Nanofluids

Nanofluids are suspensions of nanometrical size particles in a liquid base, which is usually water, oil or ethylene glycol. The potential practical use of nanofluids caused in recent years a considerable intensification of research into their properties. The most widely studied of physical properties include the fluid rheology, thermal conductivity and electrical parameters. The paper presents electrical properties of aluminium oxide (Al₂O₃) nanofluids based on ethylene glycol (EG). Nanoparticles used to produce nanosuspensions employed in measurements have size between 100-300 nm. Electrical properties was investigated in a wide range of temperatures (-10°C-55°C) and frequencies (0.02-200 kHz) using a measuring LCR bridge connected to a temperature stabilization system based on liquid nitrogen and Peltier element

Thermophysical profile of ethylene glycol based nanofluids containing two types of carbon black nanoparticles with different specific surface areas

International audienceThe paper summarizes results of experimental studies on thermophysical and electrical properties of ethylene glycol based nanofluids containing carbon black nanoparticles. Two types of nanoparticles differing in size and specific surface area were used to develop nanofluids. During the examination thermal conductivity, isobaric heat capacity, mass density, nanofluid-air surface tension, dynamic viscosity, refractive index and electrical conductivity were measured in strict controlled temperature 298.15 K. Obtained results indicate that the specific surface area has great influence on these fundamental properties of nanofluids developed with carbon nanoparticles. Finally, the enhancement of electrical conductivity described in the paper is one of the highest reported for the nanofluids in available literature