Using the benthic organism Hediste diversicolor as a test organism to study the fate of nano‐sized (AgNP) and ionic silver (Ag+) added to the water in a controlled laboratory experiment. Two different setups were made consisting of 12 sediment cores each. One was made with sediments and water (6 CN, 6 CS) and the other (6 AN, 6 AS) was similar but included the sediment dwelling polychaeta, H. diversicolor, which was used in order to investigate how bioturbation influences the fate of AgNP and Ag+. The experiment was allowed to run for 12 days. Afterwards, samples from the top, burrow, anoxic sediment and overlying water were extracted and silver concentrations were measured with an AAS apparatus. The data collected from the AAS at experimental termination showed that both AgNP and Ag+ concentrations were very small or below detection limit in the water and anoxic sediment phases and remarkably higher in the worm tissue and in the top sediment. This suggests that whether AgNP and Ag+ stay in the top sediment or is being dispersed to the deeper sediment is determined by the numeric presence of worms. Kruskal‐Wallis test and Student t‐test were performed and statistically significant differences were found between Ag+ and AgNP in the top sediments and the burrow sediments. There also seems to be a difference in the bioaccumulation between the two kinds of silver, even though there is no significant difference in the concentration between Ag+ and AgNP. Although our experiment did show some useful information, it is far from enough. The research and usage of nano science is only less than 20 years, and at present, there are still a vast amount of unknown characteristics of nanosilver. Therefore many more specific experiments should be carried out, in order to understand the implications of bioavailability and toxicity of nanosilver to the environment.
|Uddannelser||Miljøbiologi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat|
|Udgivelsesdato||26 jun. 2009|
- Hediste diversicolor