Effect of silver nanoparticles on the marine environment - Virginia Echavar…
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Fig. 2 Microbial loop. http://www.com.univ-mrs.fr The accumulation of AgNPs in the receiving estuarine environment could negatively affect the functioning of resident bacterial communities? Virginia Echavarri PhD student Supervised by Mark Hartl & Lynn Paterson Why silver nanoparticles (Fig.1) ? Incorporation in wide range of products owing to their antibacterial properties. Why bacteria? Estuarine bacterial communities play an important role in biogeochemical processes affecting food web chain, nutrient cycle (Fig. 2) and water quality. Aims of the research project Investigating the effects on nutrient cycle and water quality with a microcosm approach (Fig.3) to model natural conditions of the estuary. Minimum inhibitory concentration of AgNPs (MIC) investigated with toxicity tests developed with bacteria isolated from the Firth of Forth estuary. Fig.3 Microcosm set up with polypropylene (PP) buckets. Þ Support of the environmental policy decision making. Þ Guidance to apply a strict and coherent risk assessment framework for silver- containing materials Application Preliminary conclusions The toxicity of AgNPs is species specific. Antimicrobial mechanisms could be bacteriostatic at MIC. Microcosm approach allows to monitor the impact of AgNPs in a short period Fig.1 AgNPs used in the current project. Joint Research Centre (JMR) & Institute for Health and Consumer Protection
Effect of silver nanoparticles on the marine environment - Virginia Echavar…
Presentation at the Centre for Marine Biodiversity and Biotechnology Away Day 2012, by PhD student Virginia Echavarri Bravo
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Fig. 2 Microbial loop. http://www.com.univ-mrs.fr
The accumulation of AgNPs in the receiving estuarine environment could negatively affect the functioning of resident bacterial communities?Virginia Echavarri PhD studentSupervised by Mark Hartl & Lynn Paterson
Why silver nanoparticles (Fig.1) ? Incorporation in wide range of products owing to their antibacterial properties.
Why bacteria? Estuarine bacterial communities play an important role in biogeochemical processes affecting food web chain, nutrient cycle (Fig. 2) and water quality.
Aims of the research project
Investigating the effects on nutrient cycle and water quality with a microcosm approach (Fig.3) to model natural conditions of the estuary.
Minimum inhibitory concentration of AgNPs (MIC) investigated with toxicity tests developed with bacteria isolated from the Firth of Forth estuary.Fig.3 Microcosm set up with
polypropylene (PP) buckets.
ÞSupport of the environmental policy decision making.ÞGuidance to apply a strict and coherent risk assessment framework for silver-containing materials
Application Preliminary conclusions
The toxicity of AgNPs is species specific. Antimicrobial mechanisms could be bacteriostatic at MIC.Microcosm approach allows to monitor the impact of AgNPs in a short period of time.
Fig.1 AgNPs used in the current project. Joint Research Centre (JMR) & Institute for Health and Consumer Protection
Virginia
The rise of nanotechnology has led to an increase in the manufacturing and use of new materials that at nano scale exhibit different characteristics to their respective bulk material. Nano silver is one of those materials, and it is incorporated in a wide variety of applications, such as health and personal care products owing to their antimicrobial properties. As much of the silver is disposed of through domestic waste water (Blaser et al. 2008), the question arises whether the accumulation in the receiving estuarine environment could negatively affect the functioning of resident bacterial communities that play an important role in biogeochemical processes.
Virginia
The contribution made by heterotrophic bacteria to the flux of organic matter in the water column can be depicted in the form of a "microbial loop" . The dissolved organic matter, which is partly excreted by the phytoplankton and partly produced by the feeding activities of the zooplankton (phytoplankton debris, excretions, fecal droppings), is efficiently scavenged by the heterotrophic bacteria. The resulting bacterial biomass is consumed by heterotrophic nanoplankton and thus re-enters the food-web. The mineral elements released from organic matter thus begin a new life in the euphotic layer, where they contribute to the excess primary production: this process is known as regeneration. The pattern described above varies greatly, however, depending on the trophic state of the ecosystem in question.
Virginia
With the microcoms the impact on nutrient cycle and water quality will be analyzed. The followingparameters are under study: bacterial abundance , Chemical oxygen demand (COD), Biochemical Oxygen Demand) BOD5, NH4+,nitrate, carbon source degradation
Virginia
Gram negative and Gram positive bacteria have been exposed to AgNPs. Gram negative bacteria are in general more resistant to antibiotics and heavy metals due to the Lipopolysaccharide (LPS) membrane, which is exclusive of this group, that binds and immobilizes metal ions
