Mercury in Occupational Medicine

3 types of Mercury

Metallic

Inorganic

Organic

Elemental Mercury's Physical property

2 properties

routes of exposure

toxicity mechanism and target organs

Liquid at room temperature

Vaporises easily i.e. Volatile

Lipophilic and passes BBB and Placenta from alveoli to RBC

High specific gravity there for lead floats on it

Oxidizes to Hg2+ Binds to Sulphydryl groups and accumulates in kidneys and brain

Neurotoxicity mainly. Can also affect kidneys

Inorganic mercury

Routes of exposure

Which are the main target organs

Solid powders, either Mercurous or Mercuric HG2+ salts or compunds of chlorine, oxygen, Sulphur

Non volatile so air route exposure is rare

Upto 15% dose ingestion

Dermal is another route

Not lipid soluble so not neurotoxic

Main effect is nephrotoxic

Git as well, corrosion

3 Occupational sources of Inorganic Mercury

Chlor alkali,caustic soda

Electronics

Gold mining

Dental amalgam

Main source of organic mercury/methyl mercury

Fish, fish processing

Health effects of inorganic mercury

3 acute

3 chronic

Acute:

GIT + RENAL+ SHOCK

CHRONIC:

RENAL+NEURO+GUMS

Peripheral neuropathy (sensory)

Stomatitis,gingivitis

Mercurolentis

Nephrotoxic (ATN, proteinuria)

Chelating agent of choice for acute Inorganic mercury poisoning

Dimercaprol (BAL)

BAL or DIMERCAPROL should not be used for chelating chronic mercury poisoning

True- its for acute severe.

BAL is given intramuscularly

DMSA(SUCCIMER) is oral agent, safer, does not redsitrubute mercury which can worsen symptoms. Used for chronic

Biological monitoring for inorganic mercury salts

1. Sample and timing

Target organs of focus

Biological effect monitoring

Pre shift urine

Renal , GIT and CNS(lesser extent)

Biological effect- proteinuria, Cr, eGfr

which mercury compounds are associated with peripheral neuropathy

organic/methyl mercury - minimata disease ( incl blindness.tunnel vision, ataxia)

elemental merecury vapour

Erethism

Mad hatters disease

Elemental mercury vapor

Neuropsychiatric features: insomnia, irritability, mood and personality changes and resentment at being observed