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Barium

DESIGNATIONS

CAS No.: 7440-39-3
Registry name: Barium
Chemical name: Barium
Synonyms, Trade names: Barium
Chemical name (German): Barium
Chemical name (French): Baryum
Appearance: soft, silvery white metal

BASIC CHEMICAL AND PHYSICAL DATA

Chemical symbol: Ba
Rel. atomic mass.: 137.34 g
Density: 3.51 g/cm3 at 20C
Boiling point: 1,640C
Melting point: 725C
Vapour pressure: 0.13 Pa at 547C

Flash point: flammable and highly reactive solid. Contact with water (e.g. humidity) causes a strong reaction forming explosive mixtures of hydrogen gas and air. On heating, it readily reacts with oxygen and nitrogen.

Solvolysis/solubility: in water (at 20C): reaction to barium hydroxide 32.8 g/l, barium sulphate 0.02 g/l

BASIC DATA OF SELECTED COMPOUNDS

CAS No: 513-77-9 10361-37-2
Chemical name: Barium carbonate Barium chloride
Synonyms, Trade names: Witherite  
Chemical name (German): Bariumcarbonat Bariumchlorid
Chemical name (French): Carbonate de baryum Chlorure de baryum
Appearance: white, fine crystalline powder colourless crystals
Empirical formula: BaCO3 BaCl2
Rel. molecular mass: 197.35 g 208.25 g
Density: 4.29 g/cm3 3.91 g/cm3
Melting point: 1360C (loss of CO2) 962C
Solvolysis/solubility: in water: 2 x 10-3 wt% at 20C in water: 26.3 wt% at 20C

36.6 wt% at 100C

ORIGIN AND USE

Usage:
Metallic Ba and Ba/Al-alloys are mainly used as scavengers to remove the last traces of unwanted gases from vacuum tubes. Roughly 80 % of barium sulphate is used to increase the density of drilling fluids when drilling for oil. The remaining 20 % is used as fillers for paints and paper, as heavy concrete additives and X-ray contrast medium as well as for fireworks or explosives. Barium carbonate is used in the ceramics and glass industry as well as to combat rodents in agriculture. A further important application is the electrolysis of alkali-metal chlorides.

Origin/derivation:
Ba is an element which is found as a mineral component (heavy spa: barium sulphate) and makes up 0.04-0.05 % of the Earth's crust.

Production figures:
The consumption of barium sulphate in the Federal Republic of Germany in 1975 was about 370,000 t (DVGW, 1985).

Estimated production of BaSO4 (in 1,000 tons, 1982):

USA 1,800
Western Europe 1,030
Mid/Far East 1,890
South Africa 800
Comecon 820
World 7,250

Toxicity

Mammals:
Rat: LD 500 mg/kg, oral (barium acetate) acc. DVGW, 1985
LD 630 mg/kg, oral (barium carbonate) acc. DVGW, 1985
LD50 150 mg/kg, oral (barium chloride) acc. DVGW, 1985
LD50 355 mg/kg, oral (barium nitrate) acc. DVGW, 1985
Mouse: LD50 800 mg/kg, oral (barium carbonate) acc. DVGW, 1985
LD 7-14 mg/kg, oral (barium chloride) acc. DVGW, 1985
Rabbit: LD 236 mg/kg, oral (barium acetate) acc. DVGW, 1985
LD 170-300 mg/kg, oral (barium carbonate) acc. DVGW, 1985
Aquatic organisms:
Water flea: 83 mg/l critical level acc. DVGW, 1985
Eel: LD 2,000 mg/l (36 h) acc. DVGW, 1985
Goldfish LD 9,400 mg/l (14.5 h) acc. DVGW, 1985

Characteristic effects:

Humans/mammals: All soluble barium compounds are poisonous and readily resorbed in the gastro-intestinal tract and subsequently accumulated in the bones. The intake of between 2 and 4 g of barium chloride can prove fatal; barium ions paralyse the heart.

Acute poisoning results in nausea and diarrhoea, cardiac problems and muscular spasms as well as cardiac arrest or apnoea.

Whereas barium hydroxide is highly caustic since it forms soluble barium hydroxide in water, barium sulphate is not hazardous on account of the fact that it is virtually insoluble in water.

ENVIRONMENTAL BEHAVIOUR

Barium compounds mostly impact the environment as a result of industrial waste water. As little as 0.1 mg/l of barium is sufficient to damage micro-organisms; the self-purification capability of surface and groundwater is inhibited from 1 g/l.

ENVIRONMENTAL STANDARDS

Medium/acceptor Sector Country/organ.

Status

Value Cat. Remarks Source
Water: Surface EC

(L)

0.1 mg/l   1) acc. DVGW, 1985
Surface EC

(L)

1 mg/l   2) acc. DVGW, 1985
Drinkw AUS   1 mg/l   1973 acc. MERIAN, 1984
Drinkw CDN   1 mg/l   1978 acc. DVGW, 1985
Drinkw EC

(G)

0.1 mg/l   Approx. figure acc. DVGW, 1985
Drinkw SU   4 mg/l   1970 acc. MERIAN, 1984
Drinkw USA

L

1 mg/l     acc. DVGW, 1985
Groundw NL

G

50 g/l   Reference acc. TERRA TECH, 6/94
Groundw NL

L

625 g/l   Intervention acc. TERRA TECH, 6/94
Trough USA

(L)

1 mg/l   1968 acc. DVGW, 1985
Soil:   NL

G

200 mg/kg   Reference acc. TERRA TECH, 6/94
  NL

L

625 mg/kg   Intervention acc. TERRA TECH, 6/94
Air: Workp AUS

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp B

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp CH

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp D

L

0.5 mg/m3 MAK   DFG, 1989
Workp DDR

(L)

0.5 mg/m3 MAK   acc. MERIAN, 1984
Workp NL

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp PL

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp RO

(L)

0.5 mg/m3   Short-time value acc. MERIAN, 1984
Workp SF

(L)

0.5 mg/m3     acc. MERIAN, 1984
Workp USA

(L)

0.5 mg/m3 TWA   ACGIH, 1986
Emiss. D

L

0,1 mg/m3   find dust mass flow > 0.5 g/h acc. TA Luft, 1986
Foodstuffs:   D

G

0.5-3 mg/kg.d ADI   acc. DVGW, 1985
Drinkw D

L

1 mg/l     acc. DVGW, 1985

Note:
There is almost a total ban in the Federal Republic of Germany on the use of barium in cosmetics.
1) Mandatory value for simple physical treatment and sterilisation
2) Mandatory value for normal physical and chemical treatment and sterilisation; mandatory value for physical and refined chemical treatment, oxidation, adsorption and sterilisation
3) With mass flow of 1 kg/h and more

Comparison/reference values

Surface water
Lake Constance (1983) D 23.5 g/l acc. DVGW, 1985
Ruhr (Duisburg, 1983) D 41 g/l acc. DVGW, 1985
Denver (1966) USA 16-56 g/l acc. DVGW, 1985
Drinking water
100 communities USA 2-380 g/l acc. DVGW, 1985

Assessment/comments

Barium compounds are poisonous and highly toxic particularly to aquatic organisms. There is no possibility of comprehensive assessment since there are scarcely any data available regarding the environmental behaviour of such compounds.


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