Tributyltin Sorption Research Articles

Relation of tributyltin and triphenyltin equilibrium sorption and kinetic accumulation in carp and Ceratophyllum demersum.

Comparatively limited knowledge is known about the accumulation processes of tributyltin (TBT) and triphenyltin (TPT) in fish and aquatic plant in the freshwater environment, which has hindered a full understanding of their bioaccumulation potential and ecological risks. In the present study, sorption of TBT and TPT on dead biota of both carp and C. demersum from water via the batch equilibrium technique as well as uptake of them on live biota of both carp and C. demersum from water at a static and a dynamic kinetics tests were investigated, respectively. Both TBT and TPT exhibit a high affinity in carps and C. demersum. And C. demersum has a faster metabolism either for TBT or TPT than carp. The apparent uptake values (Cbio=1904-8831μg/kg) or bioconcentration factor (BCF=3333-44000L/kg) were one or two orders of magnitude higher than that of estimated by a simple sorption (405-472μg/kg) or lipid model (74.5-149.6μg/kg) for carp, indicating the uptake of TBT and TPT did not only depend on lipids but also oxygen ligands or macromolecules such as amino acids and proteins of the living organism. In contrast, the apparent Cbio values (149.1-926.4μg/kg) of both TBT and TPT were lower than that of estimated by sorption model (1341-1902μg/kg) for C. demersum, which were due to the rapid metabolic rate of them, especially for TBT. But no relation was observed between TBT and TPT concentrations and lipid contents in C. demersum.

Remediation of Tributyltin Contaminated Seawater by Adsorption Using nFe3O4, Activated Carbon and nFe3O4/Activated Carbon Composite Material

The remediation of tributyltin (TBT) by adsorption onto nFe3O4, activated carbon and nFe3O4/activated carbon composite material as a function of adsorbent dose, contact time, pH, stirring speed, initial TBT concentration and temperature was studied. The effect of temperature on kinetics and equilibrium of TBT sorption on the precursors and the composite was thoroughly examined. The adsorption kinetics is well fitted using a pseudo-second-order kinetic model, and the adsorption isotherm data of nFe3O4, activated carbon could be described by the Freundlich isotherm model whereas nFe3O4/activated carbon composite could be described by the Freundlich and Dubinin–Radushkevich isotherm models. Thermodynamic parameters (i.e. change in the free energy (∆G°), the enthalpy (∆H°) and the entropy (∆S°)) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. The results obtained also showed that 99.9, 99.7 and 80.1 % TBT were removed from contaminated natural seawater by nFe3O4/activated carbon composite, activated carbon and nFe3O4, respectively.

Sorption Mechanism of Tributyltin to Black Carbon in Seawater System

Two BC(black carbon) samples,BC700 and BC400,were prepared from China fir wood by pyrolytic charring at 700 and 400 ℃,respectively.The sorption behavior and mechanisms of tributyltin(TBT) on the two BC samples were evaluated as a function of seawater pH and salinity.The results indicated that BC700 had a higher specific surface area but lower content of organic matter than BC400.TBT sorption on BC700 was primarily a physical adsorption process while hydrophobic partitioning also significantly contributed to TBT sorption on BC400.Increasing salinity from 5 to 35 g/kg facilitated TBT sorption by 1.03—2.12 times as an overall result of the enhancing effective concentration of TBT because of 'salting-out' and the reducing role of electrostatic interaction because of BC surface charge neutralization.Environmental pH had a significant influence to TBT forms in the solution.It was found that TBT existed in both cationic(TBT+) and uncharged species at pH=4.00 and 6.25 but mostly in uncharged species(TBT) at pH=8.00.TBT sorption reached maximum at pH=6.25,as compared to pH=4.00 and 8.00,due presumably to multiple mechanisms involving electrostatic interaction,physical adsorption and hydrophobic partitioning between TBT and BC.In addition,XPS spectra showed that the binding energy of Sn3d5/2 peak shifted higher with decreasing pH,confirming the TBT-BC electrostatic interaction.Therefore,sorption of TBT on the BC700 was mainly physical adsorption and electrostatic interaction while hydrophobic partitioning also significantly contributed to TBT sorption on BC400.

Improved understanding of tributyltin sorption on natural and biochar‐amended sediments

A poor understanding of tributyltin (TBT) sorption on sediments has hindered an accurate evaluation of its environmental fate. The present study determined TBT sorption by a freshwater sediment (BH) and a coastal marine sediment (TZ) as influenced by pH, salinity, and biochar (BC) amendment into TZ. The isotherms were essentially linear, with K(OC) values in the range of 10(4) to 10(5) L/kg. Tributyltin sorption at pH 3.56 and 8.00 occurred mainly via partitioning. It reached maxima at pH equal to its pK(a) (=6.25) because of added ion exchange. A salinity increase from 5 to 35 practical salinity units enhanced TBT sorption at pH 3.56 and 8.00 on TZ by approximately 30% and on BH by approximately 80%, ascribed to the salting-out effect that reduced the solubilities of tributyltin hydroxide (TBTOH) and tributyltin chloride (TBTCl). At pH 6.25, the same salinity increase reduced TBT sorption on TZ by approximately 20% but enhanced TBT sorption on BH by approximately 35%. This was attributed to the enhancing role of salting out and the reducing role of metal competition for ion exchange. Tributyltin was two orders of magnitude more effectively sorbed by BC than by total organic carbon of TZ, mainly because of the high level of surface area of the BC. Although BC affinity for TBT may be significantly diminished when present in TZ, it was considered to be the primary contributor to TBT sorption from water. Biochar may thus be used to immobilize TBT in sediment for potential remediation.

Distribution and Correlation of Tributyltin and Organic Matter in the Sediments of Hakata Bay, Japan

Abstract Tributyltin (TBT) is used as effective antifouling agents in boat paints and has been found to be present in marine and freshwaters ecosystem at concentrations exceeding acute and chronic toxicity levels. In the present study, horizontal and vertical TBT distributions in the sediment of Hakata Bay, Japan, have been investigated. Basic properties of the sediment such as clay mineralogy, particle size and organic matter content were also determined, and their relations with TBT concentrations in the sediment were discussed, focusing on organic matter. Sediments in the study sites consist mostly of clay soil with clay fraction of 21 % to 35 %, and major clay minerals in the sediments were smectite, followed by vermiculite, illite, and kaolinite. TBT concentration in overlying water ranged from 13 to 94 ng⋅L−1 at locations within the harbor, and from 13 to 32 ng⋅L−1 at locations outside of the harbor. TBT concentration in top 3 cm sediment varied from 0.018 to 1.101 mg⋅kg−1. Sorption coefficient was in a range of 1.03 to 5.7×103 (L kg−1) for sediments at most stations, and on the order of 104 for sediments with higher organic matter content. The organic matter content and TBT concentration in sediments changed with depth in a similar pattern at all stations. The organic matter decreased with depth up to 12 cm and was almost constant below 12 cm. TBT concentrations appeared to be higher at depth above 12 cm than below 12 cm. A positive correlation was observed between TBT concentration and organic matter content for all core samples data. According to other researchers, an increase in TBT concentration due to increase in organic matter appears to be the results of sorption of TBT+ on negatively charged surfaces of organic matter as well as hydrophobic sorption of TBT compounds on organic matter.

Parameters estimation for reactive transport: A way to test the validity of a reactive model

The chemical parameters used in reactive transport models are not known accurately due to the complexity and the heterogeneous conditions of a real domain. We will present an efficient algorithm in order to estimate the chemical parameters using Monte-Carlo method. Monte-Carlo methods are very robust for the optimisation of the highly non-linear mathematical model describing reactive transport. Reactive transport of tributyltin (TBT) through natural quartz sand at seven different pHs is taken as the test case. Our algorithm will be used to estimate the chemical parameters of the sorption of TBT onto the natural quartz sand. By testing and comparing three models of surface complexation, we show that the proposed adsorption model cannot explain the experimental data.

Tributyltin partitioning in sediments: Effect of aging

The effect of aging on the solid/pore-water partitioning and desorption behaviour of tributyltin (TBT) in sediments was examined. Three sediment samples with contrasting physical and chemical properties were spiked with 10 mg/kg TBT and aged under sterile conditions for periods of time ranging from 1 to 84 days. Aging had a negligible effect on partitioning and desorption behaviour in a sandy sample with very low organic carbon content (0.2% w/w). In contrast, for samples with larger amounts of organic carbon (2.6% and 4.8% w/w), aging caused substantial increases in TBT sorption. For these samples, apparent distribution coefficients ( K D,app) obtained from sequential 2 h desorption experiments also exhibited a twofold increase between spiked sediments subjected to aging for 1 day and 84 days. This study demonstrates that aging effects may be an important aspect of TBT fate in contaminated sediments.

Sorption and Desorption Behavior of Tributyltin with Natural Sediments

Tributyltin (TBT) sorption to four natural sediment samples in artificial seawater was examined under a range of modified pH and salinity conditions. Three of the sediment samples were relatively pristine with regard to TBT contamination, but the fourth was a TBT-contaminated sediment from a commercial marina. Sorption of TBT was described well by linear sorption isotherms, with distribution coefficients ranging from 6.1 to 5210 L/kg depending on the pH and salinity. The sediment organic C content and particle size distribution were important determinants of sorption behavior. The presence of resident TBT in the contaminated marina sediment caused a substantial reduction in further TBT sorption. Desorption of TBT from the marina sediment was described by relatively large observed distribution coefficients ranging from 5100 to 9400 L/kg, suggesting that aging effects may reduce sorption reversibility. Increased artificial seawater salinity generally reduced TBT sorption at pH 4 and 6, but enhanced TBT sorption at pH 8. Regardless of salinity, maximum sorption of TBT was observed at pH 6, which is attributed to an optimal balance between the abundance of cationic TBT+ species and deprotonated surface ligands. Consideration of aqueous TBT speciation along with octanol-water partitioning behavior suggests that hydrophobic partitioning of TBTCl(0) to nonpolar organic matter was important for pH < 6, while partitioning of TBTOH(0) was important at higher pH.

Sorption of tributyltin onto a natural quartz sand

The aim of this study is to understand the sorption of tributyltin (TBT) onto natural quartz sand by classical batch experiments and spectroscopic surface analyses. At pH<6, the major species of TBT is the cation TBT +. Due to the presence of both the cationic part and the butyl chains, TBT should present amphiphilic properties. For concentrations lower than 40 μM, TBT sorption occurs as a homovalent 1:1 cation exchange between either H + or Na + and TBT +. The increasing affinity of TBT with respect to the different materials follows the series kaolinite⪡ natural sand < treated sand < pure quartz . From XPS analyses, where the chemical environment of Sn did not change, indicating possible complete reversibility of the TBT sorption, it seems that inner-sphere surface complexes could be formed due to the increase in the 3 d-level binding energy. At TBT concentrations higher than 100 μM, we showed by flotation experiments and XPS analysis that the surface becomes hydrophobic. After one monolayer was formed, the TBT sorption could thus be due to hydrophobic interaction between the butyl chains of the sorbed TBT and those of the TBT still available from the bulk solution. This mechanism is consistent with surface condensation and the shape of the sorption isotherm.

Sorption of tributyltin in seawater by municipal solid waste compost

AbstractThe use of municipal solid waste (MSW) compost as a sorbent for tributyltin (TBT) in seawater was investigated. TBT‐contaminated seawater, both artificially prepared and that collected from Msida Creek yacht marina (Malta), was allowed to percolate through untreated and water‐washed columns of compost and then analysed for organotins using gas chromatography‐flame photometric detection. About 90% of dissolved TBT ranging in concentration from about 800 to 8000 ngSnl−1 was sorbed by treating 500 ml solutions with 100 g untreated compost. On the other hand, no detectable breakthrough of TBT was observed from compost that had previously been washed by water to remove soluble organic matter. Breakthrough of TBT from unwashed compost is thought to be due to formation of complexes between the soluble organic matter in compost and aquated TBT, which renders the organotin more hydrophilic. The use of washed MSW compost as sorbent for the purification of TBT‐contaminated waters generated in large quantity during hull‐cleaning activities in drydocks is suggested as a mitigatory measure against the impact of TBT on the coastal marine environment. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Effect of solid surface composition on the migration of tributyltin in groundwater.

Tributyltin (TBT) is the most important organotin compound that has been introduced into aquatic ecosystems. A better understanding of its interactions with solid surfaces is essential to estimate the possibilities of TBT migration through subsurface environments. For this purpose, TBT sorption onto a porous matrix of natural origin, a quartz sand as an aquifer material, was studied at low concentration levels with a monodirectional model of column type allowing sequential investigation of sorption and desorption processes. Different treatments of the solid phase were performed by injecting alkaline solutions, NaOH at pH 10.8 or NaClO-NaCl at pH 11.5, by decreasing the ionic strength or by adding kaolinite to change the surface composition and properties. The removal of iron and aluminum (hydr)oxides from the sand surface did not affect so much the sorption (decrease in 14% as compared to sorption on the raw sand). The original use of X-ray photoelectron spectroscopy to control treatment efficiency and to characterize sand surface modifications permitted to relate TBT sorption onto the aquifer material to quartz, the main component of the sand, and clay minerals (mainly kaolinite) present at trace levels at the sand surface. A first attempt of transport modeling with these two surface sites showed the consistency of our assumption. Moreover, estimation of Langmuir-type constants showed that TBT sorption affinity for the quartz surface (KL = 26.7 L micromol(-1)) was much greater than for kaolinite (KL = 6.3 L micromol(-1)).

Distribution of tributyltin chloride in laboratory simulated estuarine microcosms

The sorption of tributyltin (TBT) chloride from aqueous solution to sediment and partitioning between overlying water and pore water were investigated in both batch sorption experiments and laboratory simulated estuarine microcosms using the natural sediment collected from Tianjin Harbor. Sorption coefficients of 8862 l/kg at 25°C and 7511 l/kg at 35°C were respectively obtained from batch adsorption isotherms. Rates of adsorption and desorption in the sediment were fast with 98% of the maximum sorbed amount by the sediment and 80% of the equilibrium aqueous TBT concentration desorbed from the sediment achieved within 30 min. The sorption of TBT on the sediment was a reversible process. The rate of TBT partitioning into pore water was more rapid than the sorption process and the apparently fast rate of the sorption in the upper sediment was due to mixing between pore water and overlying water. Salinity had little effect on the sorption of TBT on the sediment while the partitioning coefficient between pore water and surface water decreased with increasing salinity. The pH had significant effects on both sorption on the sediment and partition into the pore water. A study in simulated estuarine microcosms indicated that TBT sorption on the sediment followed the process of TBT partitioning into the pore water after TBT rapidly disappeared from the overlying water. Microbial activity promoted the distribution of TBT in the pore water and sediment. Biodegradation of TBT to DBT, MBT and even inorganic tin occurred in the lower layers of sediment samples.

Dynamic Sorptive Behavior of Tributyltin on Quartz Sand at Low Concentration Levels: Effect of pH, Flow Rate, and Monovalent Cations

The highly toxic organotin compounds which have been used as biocides in ship antifouling paints have been introduced into aquatic ecosystems. Among them, tributyltin (TBT) is the most important organotin compound which has been produced on the largest scale. Understanding its fate in the environment is therefore of primary importance to prevent its migration. TBT sorption from aqueous solutions was studied at much lower concentrations (10 nM to 2 μM) than those used in previous studies. Experiments were performed using column reactors filled with a quartz sand. The influence of physicochemical parameters on TBT partitioning, i.e. ionic strength, pH, and nature of electrolyte cation was investigated. Equilibrium times were short as TBT retention appeared to be independent of the mean pore velocity. TBT sorption was affected strongly by the pH and slightly by the ionic strength of the solution. Competitions with monovalent alkaline cations showed a small influence of Li+, Na+, K+, Rb+, with respect to Cs+ ...

A Mechanistic Approach to Tributyltin (TBT) Sorption by Marine Microflagellated AlgaPavlova lutheri

The sorption of tributyltin (TBT) by phytoplankton cells was studied by exposing the marine microflagellated alga Pavlova lutheri grown in batch culture to TBT chloride concentrations ranging from 0.37 to 74 nM (0.1 to 21 μg l−1) for a 24-hour period. The phytotoxicity of TBT was indicated by a decrease in cell density at all TBT concentrations used. TBT was tightly bound to the surface cell and was only washed out by a strong acidic solution (pH⩽3) while inner cell-absorbed TBT was only recovered by means of an organic solvent. The sorption of TBT by P. lutheri occurred via two mechanisms: a passive ionic surface adsorption followed by a facilitated intracellular absorption. The coupling/uncoupling of these two mechanisms was dependent upon the contamination level used. The cell surface adsorption of TBT was best described by the Freundlich adsorption model whereas the obstruction of the facilitated absorption mechanism was apparently related to the toxic activity of TBT towards cell components. © 1997 John Wiley & Sons, Ltd.

A study of the partitioning and sorptive behaviour of butyltins in the aquatic environment

AbstractThis study was designed to investigate the partitioning and sorptive behaviour of tributyltin(TBT), and its degradation products dibutylitin (DBT) and monobutyltin (MBT), in the aquatic environment. Factorial experiments were undertaken to determine the importance of pH and particulate matter concentration in the sorption of butyltin compounds to solid phases. Results indicate that in freshwaters MBT, and to a lesser extent TBT, will be partitioned towards the particulate phase, whereas DBT exhibits a 50:50 partitioning between particulate and solution phases. In estuarine waters, whilst MBT will almost exclusively sorb on to particulates, TBT will be predominantly in the solid‐phase fractions but 10–30% may remain in solution. DBT, in contrast, is solubilized in estuarine waters. A more detailed investigation of TBT sorption and particulate matter concentration was undertaken using adsorption isotherms on different sediment types. The results from batch isotherm tests plotted according to the Freundlich adsorption model revealed that TBT adsorption varied with sediment type, increasing in the order sandy‐silt &lt; silty‐sand &lt; silty‐clay. TBT sorption was found to be reversible, indicating that contaminated sediments may release TBT to overlying waters following sediment distrubance. Interstitial water partitioning studies indicate that TBT predominates in the particulate phase with partition coefficients for TBT higher than for DBT and MBT. The TBT partition coefficient in interstitial waters appears to be related to total organic carbon loadings.