Accumulation of aqueous and nanoparticulate silver by the marine gastropod littorina littorea

The accumulation of Ag by the marine herbivorous gastropod, Littorina littorea, has been studied in a series of exposures in which the metal was added in aqueous form and as nanoparticles, both in the presence and absence of contaminated algal food (Ulva lactuca). Significant accumulation occurred in the gill, kidney, stomach and visceral mass when the snail was exposed to aqueous Ag in the absence of food. Despite the consumption of U. lactuca that had been previously contaminated by Ag, no accumulation was observed from the dietary route. When added as nanoparticles, accumulation of Ag was only measured in the head and gill and only in the absence of contaminated food. These observations suggest that Ag is most bioavailable to L. littorina when in true solution and that Ag measured in external tissues of the snail following exposure to nanoparticles arises from some physical association that does not result in significant transfer of the metal to internal organs. © 2012 Springer Science+Business Media Dordrecht

Metal accumulation kinetics by the estuarine macroalga, Fucusceranoides

The kinetics of Cu, Cd and Pb accumulation by the macroalga, Fucus ceranoides, was studied under simulated estuarine conditions. Accumulation of Cu and Pb proceeded via a pseudo-first-order reaction that was reversible, suggesting desorption or efflux of accumulated metal, with forward rate constants on the order of 0.1h-1. For both metals, reaction reversibility increased and the equilibrium constant decreased with increasing salinity (from 1 to 33.5) and system response times were <10h throughout. Accumulation of Cd proceeded via a first-order reaction that was irreversible, suggesting little desorption or efflux of metal, with rate constants that decreased with increasing salinity (from 0.023 to 0.015h-1) and reaction half-lives ranging from approximately 30-50h. Inorganic equilibrium speciation calculations suggest that interactions of Cu, Cd and Pb principally involve the respective free ions, but that additional ions (e.g. CdCl+) and biotic processes may also be significant. •Accumulation of Cu, Cd and Pb by the estuarine macroalga, Fucus ceranoides, decreases along a salinity gradient.•Accumulation of Cu and Pb proceeds via a reversible pseudo-first-order reaction.•In contrast, accumulation of Cd proceeds via an irreversible first-order reaction.•Differences in reaction mechanisms are attributed to differences in the ability of metals to be internalised. © 2013 Elsevier Ltd

Extra- and intra-cellular accumulation of platinum group elements by the marine microalga, Chlorella stigmatophora.

To better understand the marine biogeochemistry of the platinum group elements (PGE), Rh(III), Pd(II) and Pt(IV) were added in combination and at ppb concentrations to cultures of the marine microalga, Chlorella stigmatophora, maintained in sea water at 15 °C and under 60 μmol m(-2) s(-1) PAR. The accumulation of PGE was established in short-term (24-h) exposures, and under varying conditions of algal biomass and PGE concentration, and in a longer-term exposure (156-h) by ICP-MS analysis of sea water and nitric acid digests and EDTA washes of the alga. In short-term exposures, and under all conditions, the extent of accumulation by C. stigmatophora was in the order: Rh > Pd >> Pt; and Pd was internalised (or resistant to EDTA extraction) to a considerably greater extent than Rh and Pt. Accumulation isotherms were quasi-linear up to added PGE concentrations of 30 μg L(-1) and all metals displayed a significant reduction in accumulation on a weight-normalised basis with increasing density (biomass) of C. stigmatophora, an effect attributed to the production of exudates able to stabilise metals in sea water through complexation. In the longer-term exposure, kinetic constraints on the reactivities of Rh and, in particular, Pt, resulted in final degrees of accumulation and internalisation by C. stigmatophora that were greatest for Rh and similar between Pd and Pt. Among the PGE, therefore, Rh is predicted to participate in biological removal and transport processes in the marine environment to the greatest extent while decoupling in the biogeochemistries of Pd and Pt is predicted in shorter-term or more transient processes

Environmental pollutants in blood donors: The multicentre Norwegian donor study

Objectives - The aim of this study was to measure blood concentrations of environmental pollutants in Norwegian donors and evaluate the risk of pollutant exposure through blood transfusions. Background - Transfused blood may be a potential source of exposure to heavy metals and organic pollutants and presents a risk to vulnerable patient groups such as premature infants. Methods/Materials - Donors were randomly recruited from three Norwegian blood banks: in Bergen, Tromsø and Kirkenes. Selected heavy metals were measured in whole blood using inductively coupled plasma mass spectrometry (ICP‐MS), and perfluoroalkyl substances (PFAS) were measured in serum by ultrahigh‐pressure liquid chromatography coupled with a triple‐quadrupole mass spectrometer (UHPLC‐MS/MS). Results - Almost 18% of blood donors had lead concentrations over the limit suggested for transfusions in premature infants (0.09 μmol/L). About 11% of all donors had mercury concentrations over the suggested limit of 23.7 nmol/L. Cadmium was higher than the limit, 16 nmol/L, in 4% of donors. Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) concentrations were over the suggested limit of 0.91 ng/mL in 68% and 100% of the donors, respectively. PFAS concentrations and heavy metal concentrations increased with donor's age. Conclusion - A considerable percentage of donors had lead, PFOS and PFOA concentrations over the suggested limits. In addition, at each study site, there were donors with high mercury and cadmium concentrations. Selecting young donors for transfusions or measurements of pollutants in donor blood may be a feasible approach to avoid exposure through blood transfusions to vulnerable groups of patients such as premature infants

Target product profiles for protecting against outdoor malaria transmission.

BACKGROUND\ud \ud Long-lasting insecticidal nets (LLINs) and indoor residual sprays (IRS) have decimated malaria transmission by killing indoor-feeding mosquitoes. However, complete elimination of malaria transmission with these proven methods is confounded by vectors that evade pesticide contact by feeding outdoors.\ud \ud METHODS\ud \ud For any assumed level of indoor coverage and personal protective efficacy with insecticidal products, process-explicit malaria transmission models suggest that insecticides that repel mosquitoes will achieve less impact upon transmission than those that kill them outright. Here such models are extended to explore how outdoor use of products containing either contact toxins or spatial repellents might augment or attenuate impact of high indoor coverage of LLINs relying primarily upon contact toxicity.\ud \ud RESULTS\ud \ud LLIN impact could be dramatically enhanced by high coverage with spatial repellents conferring near-complete personal protection, but only if combined indoor use of both measures can be avoided where vectors persist that prefer feeding indoors upon humans. While very high levels of coverage and efficacy will be required for spatial repellents to substantially augment the impact of LLINs or IRS, these ambitious targets may well be at least as practically achievable as the lower requirements for equivalent impact using contact insecticides.\ud \ud CONCLUSIONS\ud \ud Vapour-phase repellents may be more acceptable, practical and effective than contact insecticides for preventing outdoor malaria transmission because they need not be applied to skin or clothing and may protect multiple occupants of spaces outside of treatable structures such as nets or houses

Application of field-portable-XRF for the determination of trace elements in deciduous leaves from a mine-impacted region

publisher: Elsevier articletitle: Application of field-portable-XRF for the determination of trace elements in deciduous leaves from a mine-impacted region journaltitle: Chemosphere articlelink: https://doi.org/10.1016/j.chemosphere.2018.06.110 content_type: article copyright: © 2018 Elsevier Ltd. All rights reserved

The changing nature of risk and risk management: the challenge of borders, uncertainty and resilience

No abstract available

HLA-DR genotyping and mitochondrial DNA analysis reveal the presence of family burials in a fourth century Romano-British Christian cemetery

In Colchester, Britain's oldest recorded town, during the Roman period there were areas which were clearly used solely as cemeteries. One o f the most significant is at Butt Road, which includes a late Roman probable Christian cemetery with an associated building, apparently a church, that overlies and developed from a pagan inhumation cemetery. DNA was extracted from the long bones (femurs) of 29 individuals, mostly from a large complex of burials centered on two timber vaults. These were thought to comprise a number of family groupings, deduced from osteological analysis, stratigraphical and other considerations. The use of a modified version of the silica-based purification method recovered nanogram quantities of DNA/gram of bone. Two-stage amplification, incorporating primer-extension preamplification-polymerase chain reaction, permitted simultaneous amplification of both mitochondrial and nuclear DNA. Sequence-specific oligonucleotide probes yielded human leukocyte antigen (HLA)-DR typing of seven samples, with four revealing the infrequent HLA-DR10 genotype. Examination of the control region of mitochondrial DNA (mtDNA) by direct sequencing revealed polymorphisms yet to be reported in the modern population. HLA-DRB typing and mtDNA analysis affirmatively supported kinship among some, if not all, individuals in the "vault complex" and demonstrate a continental European origin of the individuals investigated

Search For Companions Of Nearby Isolated Galaxies

The radial velocities are measured for 45 galaxies located in the neighborhoods of 29 likely isolated galaxies in a new catalog. We find that about 85% of these galaxies actually are well isolated objects. 4% of nearby galaxies with V_LG<3500 km/s are this kind of cosmic "orphan".Comment: 7 pages, 2 figure