Mercuric(II) chloride

7487-94-7

Manufacture of calomel and other mercury compounds,
disinfectant, organic synthesis, analytical reagent,
metallurgy, tanning, catalyst for vinyl chloride, sterilant for
seed potatoes; fungicide, insecticide, and wood preservative;
embalming fluids, textile printing, dry batteries, photography,
process engraving and lithography.

White crystals or powder, odorless.

271.49

Transformation to methylmercury is the most important part of Hg
cycle in the environment. 
Hg is strongly bound to organic
matter is soil and sediment. - 
Inorganic Hg compounds are
methylized abiotically in the presence of methylcobalamine
(B12-CH3) and biotically with help of enzymes
(Hg2+ -> CH3Hg+ + /(CH3)2Hg) (Kaiser & Tölg 1980).

Organic Hg compounds kan be formed and break up chemically,
biochemically and through photosynthesis as well in atmosphere as
in aquatic environment: CH3Hg+ <-> (CH3)2Hg <-> Hg <-> Hg2+ (Anon.
1989).

Inorganic Hg is mainly stored in kidneys (WHO 1976).

Organic Hg compounds decompose to inorganic Hg and accumulates in
kidneys (WHO 1976).

Methylmercury is absorbed in alimentary canal 90 - 100 %
after intake with food, whereas inorganic Hg is absorbed less
than 15 % (WHO 1976).

Brains seem to be very sensitive to methylmercury and for Hg
vapour  (Berlin 1986).

Methylmercury is very slowly decombosed mainly through
faeces (Berlin 1986).

Inorganic bivalent Hg compounds and unstabile organic Hg
compounds induce damages in kidneys (Berlin 1986).

Methylmercury has effects on the central nervous system -
motoric and mental disorders etc. 
(Berlin 1986).

Toxicity threshold (cell multiplication inhibition test):
bacteria (Pseudomonas putida): 0.01 mg/l
(Bringmann & Kühn 1980a)

Catla catla, 0.370 mg/l, 1 d, biochemical effect (change in
physiochemical process including glycogen uptake, cholesterol
levels and lipid analysis) (Rai 1987).

Chara vulgaris, 0.000001 M, 7 d, measurable change in length
and/or weight (Heumann 1987).

Cyprinus carpio, 0.200 mg/l, change in rate of ingestion or
fecal pellet production (Muthukrishnan et al. 1986).

Lepidocephalus thermalis, 0.070 mg/l, 10 d, histological effect
(presence of physical damage to tissues) (Victor et al. 1986).

LC50, 96hr, 0.37 mg/l, gastropod (Holcombe et al. 1983).

Chara vulgaris, 0.000001 M, 7 d, 100 % mortality including
algicidal and herbicidal effects (Heumann 1987).

LC50, 48hr, 0.18 mg/l, Tubificidae
LC50, 48hr, 0.55 mg/l, Chironomus gr. thummi
LC50, 48hr, 0.32 mg/l, Erpobdella octoculata
LC50, 48hr, 0.61 mg/l, Lymnaea stagnalis
LC50, 48hr, 0.075 mg/l, Dugesia cf. lugubris
LC50, 48hr, 0.076 mg/l, Hydra oligactis
LC50, 48hr, 0.22 mg/l, Corixa punctata
LC50, 48hr, 10.3 mg/l, Ischura elegans
LC50, 48hr, 0.17 mg/l, Nemoura cinerea
LC50, 48hr, 0.05 mg/l, Cloeon dipterum
(Slooff 1983)

LC50, 96hr, 0.37 mg/l, static, Aplexa hypnorum
(Holcombe et al. 1983)

Toxicity threshold (cell multiplication inhibition test):
green algae (Scenedesmus quadricauda): 0.07 mg/l
protozoa (Entosiphon sulcatum): 0.018 mg/l
(Bringmann & Kühn 1980a)

EC0, Microcystis aeruginosa, 0.05 mg/l (DABAWAS 1982).

Phytoplankton, marine, pht, 0.001 mg/l (Knauer & Martin 1972). 
Daphnia, rpd, 0.0034 mg/l (Biesinger & Christensen 1972).