Norwegian researchers assessed the uptake, excretion and biodistribution of nanoparticles in the earthworm Eisenia fetida. Tracing engineered nanoparticles in complex media is difficult, and there are few data on the exposure of soil biota to engineered nanoparticles. This study looked at the effect of neutron activated cobalt and silver nanoparticles, as well as soluble cobalt and silver salts. The concentrations of nanoparticles in the worms after four months were 88 percent and 69 percent for the cobalt ions and nanoparticles, respectively. The corresponding values for silver ions and nanoparticles were 2.3 and 0.4 percent. Silver ions and nanoparticles in earthworms were excreted quickly, while only 32 percent of the accumulated cobalt was excreted within four months. The team found a high accumulation of cobalt in blood and the digestive tract. The authors conclude that silver ions and nanoparticles were more inert, while the cobalt nanoparticles showed significant dissolution and release of ions. The abstract, and a link to the full article, can be viewed online at the link below.
http://informahealthcare.com/doi/abs/10.3109/17435390.2011.569094