THESIS
2014
iv leaves, v-xiii, 76 pages : illustrations ; 30 cm
Abstract
Along with the extensive application of silver nanoparticles (AgNPs), growing concerns have been paid to their potential risks on aquatic organisms. The present study investigated the potential risk of AgNPs on marine fish, including both waterborne and dietary AgNPs exposures. In the waterborne exposure, we found that fast aggregation of AgNPs would proceed immediately in the high saline medium (15 psu), while the addition of Tween 20 (20 μM ) could well stabilize AgNPs against aggregation even in the 30 psu salinity medium. Uptake rate constants (k
u) of AgNPs were less than half of the soluble Ag at low salinities (1 and 5 psu), while limited bioavailability of c-AgNPs was observed at high salinities (15 and 30 psu). However, the Tween 20 stabilized AgNPs (t-AgNPs) were accumulated by...[
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Along with the extensive application of silver nanoparticles (AgNPs), growing concerns have been paid to their potential risks on aquatic organisms. The present study investigated the potential risk of AgNPs on marine fish, including both waterborne and dietary AgNPs exposures. In the waterborne exposure, we found that fast aggregation of AgNPs would proceed immediately in the high saline medium (>15 psu), while the addition of Tween 20 (20 μM ) could well stabilize AgNPs against aggregation even in the 30 psu salinity medium. Uptake rate constants (k
u) of AgNPs were less than half of the soluble Ag at low salinities (1 and 5 psu), while limited bioavailability of c-AgNPs was observed at high salinities (15 and 30 psu). However, the Tween 20 stabilized AgNPs (t-AgNPs) were accumulated by medaka at comparable rate as the soluble Ag, indicating the importance of dispersion for bioavailability of AgNPs in a highly ionic environment. In the dietary exposure, we found that the assimilation efficiency (AE) of Ag (AgNO
3, 20 and 80 nm AgNPs) from contaminated brine shrimp in the medaka was quite low (<6%) and independent of food Ag (20 nm AgNPs) concentration. However, even this small amount of assimilated Ag (from AgNPs contaminated food) generated toxic effects (e.g., inhibition of Na
+/K
+-ATPase and SOD activity, reduction of total body length and WC) on medaka during the 28-day chronic dietary exposure. The overall study highlighted the potential of AgNPs-contaminated food by generating toxicity to marine fish, while less impact was likely from the waterborne exposure in the high saline environment.
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