Metallic liquid mercury
Metallic liquid mercury is relatively harmless. «If mercury is swallowed most of it passes through your body and very little is absorbed. If you touch mercury for a short period of time a small amount may pass through your skin, but not enough to harm you.» . However, the problem is that metallic mercury evaporates at room temperature at a rate of 0.056 mg/(h·cm2) . By comparison, the evaporation rate for water is 10 mg/(h·cm2) at room temperature . Mercury vapors are absorbed through the lungs very easily and can cause both acute and chronic poisoning. For this reason, mercury should never be stored in the open and, if any drops are spilled, they must be collected immediately.
The sparingly soluble, inorganic mercury(I) compounds have low toxicity when taken up orally (but not through the skin!).
Mercury(II) compounds are more readily soluble and therefore much more toxic. Toxicity to fish: LC50 – Oncorhynchus mykiss (rainbow trout) – 0.016 mg/L – 96 h .
Mercury vapor, which is already formed at room temperature, is highly toxic: vapor with a mercury concentration exceeding the TLV (threshold limit value) or OEL (occupational exposure limit value) causes chronic poisoning after prolonged breathing for 5 to 8 hours per day. The limit values vary depending on the country and range between 20 and 100 µg/m3 of air . Despite the large number of laboratories involved in polarographic/voltammetric work, sensible and proper handling has ensured that not one single case of mercury poisoning has been reported to date. The real Hg concentrations measured in the laboratory atmosphere are consistently far below the TLV.
Organic mercury compounds
Organic mercury compounds are very toxic. Dimethylmercury is an extremely toxic form of organic mercury, and very small exposures can cause severe and irreversible delayed neurotoxicity, including death. Dimethylmercury is thought to be metabolized to methylmercury prior to crossing the blood-brain barrier. Dimethylmercury is quickly absorbed through intact skin, and it will penetrate latex or polyvinyl gloves. It is highly volatile, will readily evaporate, and can be inhaled .
 Mercury Quick Facts – Health Effects of Mercury Exposure, Agency for Toxic Substances and Disease Registry, www.atsdr.cdc.gov/mercury/docs/healtheffectsmercury.pdf
 F. Asdrubali, A scale model to evaluate water evaporation from indoor swimming pools, Energy and Buildings, 41 (2009), 311–319
 Material safety data sheet for mercury(II) chloride, www.sigmaaldrich.com
 Occupational Safety and Health Guideline for Mercury Vapor. https://www.osha.gov/dts/chemicalsampling/data/CH_250510.html
 Technische Regeln für Gefahrstoffe 900 – Arbeitsplatzgrenzwerte http://www.baua.de/de/Themen-von-A-Z/Gefahrstoffe/TRGS/TRGS-900.html
 Bundesamt für Gesundheit – Quecksilber – Factsheet Quecksilber http://www.bag.admin.ch/themen/chemikalien/00228/03912/index.html?lang=de
 European Commission, Brussels, BiPRO 16 April 2010, Requirements for facilities and acceptance criteria for the disposal of metallic mercury, http://ec.europa.eu/environment/chemicals/mercury/pdf/bipro_study20100416.pdf
 John Risher, Ph.D., Rob DeWoskin, Ph.D. 1999, Agency for toxic substances & disease registry. Toxicological Profile for Mercury. 1999. http://www.atsdr.cdc.gov/toxprofiles/tp46.pdf