Metal release and speciation of released chromium from a biomedical CoCrMo alloy into simulated physiologically relevant solutions

Abstract Background Mine tailings are hostile environment. It has been well documented that several microbes can inhabit such environment, and metagenomic reconstruction has successfully pinpointed their activities and community structure in acidic tailings environments. We still know little about the microbial metabolic capacities of alkaline sulphidic environment where microbial processes are critically important for the revegetation. Microbial communities therein may not only provide soil functions, but also ameliorate the environment stresses for plants’ survival. Results In this study, we detected a considerable amount of viable bacterial and archaeal cells using fluorescent in situ hybridization in alkaline sulphidic tailings from Mt Isa, Queensland. By taking advantage of high-throughput sequencing and up-to-date metagenomic binning technology, we reconstructed the microbial community structure and potential coupled iron and nitrogen metabolism pathways in the tailings. Assembly of 10 metagenome-assembled genomes (MAGs), with 5 nearly complete, was achieved. From this, detailed insights into the community metabolic capabilities was derived. Dominant microbial species were seen to possess powerful resistance systems for osmotic, metal and oxidative stresses. Additionally, these community members had metabolic capabilities for sulphide oxidation, for causing increased salinity and metal release, and for leading to N depletion. Conclusions Here our results show that a considerable amount of microbial cells inhabit the mine tailings, who possess a variety of genes for stress response. Metabolic reconstruction infers that the microbial consortia may actively accelerate the sulphide weathering and N depletion therein.

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Tribocorrosion of a CoCrMo alloy in sulfuric acid – Glycerol mixtures

Wear ◽

10.1016/j.wear.2020.203443 ◽

2020 ◽

Vol 458-459 ◽

pp. 203443

Author(s):

Shoufan Cao ◽

Stefano Mischler

Keyword(s):

Sulfuric Acid ◽

Cocrmo Alloy

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Modeling heavy metal release in the epiphytic lichen Evernia prunastri

Environmental Science and Pollution Research ◽

10.1007/s11356-021-12620-7 ◽

2021 ◽

Author(s):

Andrea Vannini ◽

Luca Paoli ◽

Riccardo Fedeli ◽

Sharon Kwambai Kangogo ◽

Massimo Guarnieri ◽

...

Keyword(s):

Heavy Metal ◽

Remote Area ◽

Metal Release ◽

Evernia Prunastri ◽

Epiphytic Lichen ◽

Pollution Levels ◽

Short Period ◽

High Pollution ◽

Heavy Metal Release ◽

Very High

AbstractIn this study, the release of Cu2+ and Zn2+ was investigated and modeled in the epiphytic lichen Evernia prunastri. Samples were incubated with solutions containing these metals at ecologically relevant concentrations (10 and 100 μM) and then transplanted to a remote area and retrieved after 1, 2, 3, 6, 12, and 18 months. The results showed that, after 12 months, all samples faced similar metal reductions of ca. 80–85%, but after this period, all the involved processes seem to be no longer capable of generating further reductions. These results suggest that the lichen E. prunastri can provide information about environmental improvements after exposure to high or very high pollution levels in a relatively short period of time.

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Physical Properties of Electropolished CoCrMo Alloy Coated with Biodegradable Polymeric Coatings Releasing Heparin after Prolonged Exposure to Artificial Urine

Materials ◽

10.3390/ma14102551 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2551

Author(s):

Wojciech Kajzer ◽

Janusz Szewczenko ◽

Anita Kajzer ◽

Marcin Basiaga ◽

Joanna Jaworska ◽

...

Keyword(s):

Physical Properties ◽

Crevice Corrosion ◽

Mass Density ◽

Polymer Coatings ◽

Metal Substrate ◽

Reference Level ◽

Polymeric Coatings ◽

Initial State ◽

Cocrmo Alloy ◽

Artificial Urine

In this study, we aimed to determine the effect of long-term exposure to artificial urine on the physical properties of CoCrMo alloy with biodegradable heparin-releasing polymeric coatings. Variants of polymer coatings of poly(L,L-lactide-ɛ-caprolactone) (P(L,L-L/CL)) and poly(D,L-lactide-ɛ-caprolactone) (P(D,L-L/CL)) constituting the base for heparin-releasing (HEP) polyvinyl alcohol (PVA) coatings were analyzed. The coatings were applied by the dip-coating method. Heparin was used to counteract the incrustation process in the artificial urine. The study included tests of wettability, resistance to pitting and crevice corrosion, determination of the mass density of metal ions penetrating into the artificial urine, and the kinetics of heparin release. In addition, microscopic observations of surface roughness and adhesion to the metal substrate were performed. Electrolytically polished CoCrMo samples (as a reference level) and samples with polymer coatings were used for the tests. The tests were conducted on samples in the initial state and after 30, 60, and 90 days of exposure to artificial urine. The analysis of the test results shows that the polymer coatings contribute by improving the resistance of the metal substrate to pitting and crevice corrosion in the initial state and reducing (as compared with the metal substrate) the mass density of metal ion release into the artificial urine. Moreover, the PVA + HEP coating, regardless of the base polymer coatings used, contributes to a reduction in the incrustation process in the first 30 days of exposure to the artificial urine.

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