Uptake of Lipophilic Organic Cu, Cd, and Pb Complexes in the Coastal Diatom Thalassiosira weissflogii

Phinney, Jonathan T.; Bruland, Kenneth W.

doi:10.1021/es00060a006

Cited by 156 publications

(142 citation statements)

References 15 publications

Supporting

Mentioning

133

Contrasting

Unclassified

Order By: Relevance

“…Sloof et al, 1995), metal per cell (e.g. Phinney and Bruland, 1994). For most studies, metal uptake results should be normalised per unit of cellular surface area and expressed as fluxes (e.g., mol m -2 s -1 ) in order to facilitate inter-study comparisons.…”

Section: -H Ic 50 )mentioning

confidence: 99%

Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity

Twiss

Errécalde²,

Fortin

et al. 2001

Chemical Speciation & Bioavailability

View full text Add to dashboard Cite

Chemical Speciation and Bioavailability (2001), 13(1) ABSTRACTThe bioavailability and toxicity of a dissolved metal are closely linked to the metal's chemical speciation in solution. A variety of inorganic and organic ligands are often used in laboratory toxicity tests to control the concentration of labile trace metal in solution. Computerised chemical speciation models based on thermodynamic principles can be used to estimate metal speciation under such experimental conditions. However, these models are sensitive to the quality of their thermodynamic databases. Detailed protocols for the incorporation of reliable equilibrium formation constants into widely available computer chemical speciation programs (e.g., MINEQL+ and MINTEQ) are provided. The examples demonstrate both the benefits and the potential pitfalls involved in the use of chemical speciation models. The application of chemical speciation modelling to metal toxicity studies is discussed and guidelines are proposed for its proper use. Both defined media and chemical speciation programs have co-existed for two decades but the combined use of these techniques has been reserved for those possessing in-depth knowledge of both chemistry and biology. The techniques presented should enable an investigator with basic biological, chemical and computing skills to design an aqueous medium and incorporate correct thermodynamic constants into a computer chemical speciation program, starting from a standardised database, thereby providing a sound framework for critically assessing the biological response of a particular test organism to a given metal.

show abstract

Section: -H Ic 50 )mentioning

confidence: 99%

Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity

Twiss

Errécalde²,

Fortin

et al. 2001

Chemical Speciation & Bioavailability

View full text Add to dashboard Cite

show abstract

“…The passive diffusion of metal complexes has been observed for complexes involving synthetic organic ligands, including 8-hydroxyquinoline (Ox), diethyldithiocarbamate (DDC) and ethylxanthate (XANT), [9][10][11] and for inorganic metal complexes such as HgCl 2 0 . [12] The passive diffusion of AgCl 0 remains questionable.…”

Section: Introductionmentioning

confidence: 99%

“…In such a case, metal complexes could diffuse into the cytosol where the metal could dissociate from the complex and bind with intracellular ligands. [10] This implies that the bioaccumulation of lipophilic metal complexes would not simply be dependent on complex permeability (or the octanol-water partition coefficient, K ow , of the complex) but rather would be driven to some extent by the re-equilibration of the complex within the cell. For example, whereas (CH 3 ) 2 their bioaccumulation by a marine alga (Thalassiosira weissflogii) is lower, presumably because elemental mercury and dimethylmercury do not readily form complexes with intracellular ligands.…”

Section: Introductionmentioning

confidence: 99%

“…For example, whereas (CH 3 ) 2 their bioaccumulation by a marine alga (Thalassiosira weissflogii) is lower, presumably because elemental mercury and dimethylmercury do not readily form complexes with intracellular ligands. [12] Generally speaking, the observed uptake rates of lipophilic metal complexes are usually at least an order of magnitude higher than their hydrophilic metal counterparts, [10,11,16,17] which makes this mechanism potentially important for certain metals. Furthermore, uptake is sensitive to the pH of the medium, with a decreased bioaccumulation of the lipophilic metal complexes at low pH, potentially due to a reduction in the electrostatic repulsion between adjacent phospholipids, leading to their tighter packing and a decreased membrane permeability.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

When are metal complexes bioavailable?

Zhao¹,

Campbell²,

Wilkinson³

2016

Environ. Chem.

View full text Add to dashboard Cite

Environmental context. The concentration of a free metal cation has proved to be a useful predictor of metal bioaccumulation and toxicity, as represented by the free ion activity and biotic ligand models. However, under certain circumstances, metal complexes have been shown to contribute to metal bioavailability. In the current mini-review, we summarise the studies where the classic models fail and organise them into categories based on the different uptake pathways and kinetic processes. Our goal is to define the limits within which currently used models such as the biotic ligand model (BLM) can be applied with confidence, and to identify how these models might be expanded.Abstract. Numerous data from studies over the past 30 years have shown that metal uptake and toxicity are often best predicted by the concentrations of free metal cations, which has led to the development of the largely successful free-ion activity model (FIAM) and biotic ligand model (BLM). Nonetheless, some exceptions to these classical models, showing enhanced metal bioavailability in the presence of metal complexes, have also been documented, although it is not yet fully understood to what extent these exceptions can or should be generalised. Only a few studies have specifically measured the bioaccumulation or toxicity of metal complexes while carefully measuring or controlling metal speciation. Fewer still have verified the fundamental assumptions of the classical models, especially when dealing with metal complexes. In the current paper, we have summarised the exceptions to classical models and categorised them into five groups based on the fundamental uptake pathways and kinetic processes. Our aim is to summarise the mechanisms involved in the interaction of metal complexes with organisms and to improve the predictive capability of the classic models when dealing with complexes.

show abstract

“…These characteristics, coupled with the high exchangeability of adsorbed Cd, explain why desorption of Cd from suspended particles is a common observation in many estuaries of low to moderate concentrations of DOC (Kraepiel et al 1997;Martino et al 2002) and ensure that in seawater, where particle concentrations are typically a few milligrams per liter, more than 99% Cd occurs in hydrophilic aqueous form. In organic-rich environments, these characteristics are still evident, but aqueous Cd is more hydrophobic and potentially more bioavailable via cell or gill penetration (Phinney and Bruland 1994), and binding with suspended particles assumes a more covalent or hydrophobic nature.…”

Section: Metal Adsorption and Partitioning-sediment-water Distributiomentioning

confidence: 99%

Speciation and partitioning of cadmium and zinc in two contrasting estuaries:The role of hydrophobic organic matter

Turner

Roux

Millward

2004

Limnology & Oceanography

View full text Add to dashboard Cite

The hydrophobicity and particle-water interactions of cadmium (Cd) and zinc (Zn) in an ''organic-poor'' estuary (Plym, United Kingdom) and an ''organic-rich'' estuary (Beaulieu, United Kingdom) have been investigated using radiotracers. The hydrophobic fraction of dissolved Cd (retained by a reverse-phase C 18 column) was about 50% in the River Beaulieu and less than 10% in the River Plym, and in both cases this fraction decreased rapidly with increasing salinity, such that only a few percent was hydrophobic at salinities above 10. Hydrophobicity of Cd was unaffected by the addition of suspended sediment particles, indicating that hydrophobic and hydrophilic forms adsorb in accordance with their relative abundance or that rapid reequilibration of dissolved Cd species occurs after specific forms have undergone adsorption. In the Plym, a logarithmic, salinity-dependent reduction in the sediment-water distribution coefficient, K D , and a high proportion of adsorbed Cd bound exchangeably indicate that particle-water interactions of Cd in environments of moderate concentrations of organic matter are governed by inorganic processes. In the Beaulieu, more uniform K D s and a significantly lower exchangeability of adsorbed Cd indicate that organic interactions might also be important. In both estuaries, the hydrophobic fraction of dissolved Zn was between about 80% and 100% and displayed an increase with increasing salinity and a reduction in the presence of suspended sediment particles. Throughout the Beaulieu, and in the Plym above salinities of about 4, K D also increased with increasing salinity. These observations were interpreted and modeled in terms of the preferential uptake and salting out of hydrophobic complexes of Zn and indicate that, regardless of the concentration of organic matter, the speciation and uptake of Zn in many estuaries might be strongly influenced by hydrophobic interactions.It is becoming increasingly evident that one of the principal controls on the adsorption of transition metals to mineral surfaces is the concentration and nature of organic ligands. Davis and Leckie (1978) were among the first to study the effects of a range of different synthetic organic ligands on the adsorption of trace metals to hydrous oxides, and they demonstrated that metal adsorption was either enhanced or reduced depending on whether or not coordinating groups were involved in binding with the mineral surface. A general observation of the many studies undertaken since is that in the presence of most (but not all) organic ligands, metal adsorption is enhanced at low pH and reduced at high pH (Warren and Haack 2001).Far less often studied are the effects of natural organic ligands on the adsorption of metals to natural, heterogeneous (and often organic-rich) suspended particles. Such studies rely on the addition of a radiotracer analogue of the metal of interest to a natural particle suspension and on controlling the concentration (or presence) of dissolved organic ligands. Accordingly, Paulson et al. (199...

show abstract

Uptake of Lipophilic Organic Cu, Cd, and Pb Complexes in the Coastal Diatom Thalassiosira weissflogii

Cited by 156 publications

References 15 publications

Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity

Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity

When are metal complexes bioavailable?

Speciation and partitioning of cadmium and zinc in two contrasting estuaries:The role of hydrophobic organic matter

Contact Info

Product

Resources

About