Copper rates, and carcass dressing percentages. Chronic copper toxicity does not normally occur in humans because of transport systems that regulate absorption and excretion. Autosomal recessive mutations in copper transport proteins can disable these systems, leading to Wilson's disease with copper accumulation and cirrhosis of the liver in persons who have inherited two defective genes. Elevated copper levels have also been linked to worsening symptoms of Alzheimer's disease. In the US, the Occupational Safety and Health Administration (OSHA) has designated a permissible exposure limit (PEL) for copper dust and fumes in the workplace as a time-weighted average (TWA) of 1 mg/m.
Nanoparticles for drug delivery to the brain cells’ mitochondria and endoplasmic reticulum. This leads to further issues in cellular toxicity, such as damage to DNA and disruption of cellular pathways. Silver nanoparticles in particular have a higher degree of toxicity compared to other metal nanoparticles such as gold or iron. Silver nanoparticles can circulate through the body and accumulate easily in multiple organs, as discovered in a study on the silver nanoparticle distribution in rats. Traces of silver accumulated in the rats’ lungs, spleen, kidney, liver, and brain after the nanoparticles were injected subcutaneously. In addition, silver nanoparticles generate more reactive oxygen species compared to other metals,