Zinc

CHEMICAL SUBSTANCE IDENTIFICATION

Chemical name                 

 Zinc

Synonyms                           

 Zinc dust, zinc powder, blue powder [6]

IUPAC name

 zinc [1]

CAS No

7440-66-6 [1]

REACH registration number

EC No

Molecular formula              

Zn

Substance group/chemical family

Mono constituent substance, Metal, Transition metal

Appearance

Physical state

Odour

Form

    Colour

solid at 20°C and 1013 hPa [1]

odourless  [1]

powder or massive metal  [1]

light grey (powder) or shiny silver (metal) [1]

USES AND HANDLING ISSUES

Relevant identified uses

Zinc uses range from metal products to rubber and medicines. About three-fourths of zinc used is consumed as metal, mainly as a coating to protect iron and steel from corrosion (galvanized metal), as alloying metal to make bronze and brass, as zinc-based die casting alloy, and as rolled zinc. The remaining one-fourth is consumed as zinc compounds mainly by the rubber, chemical, paint, and agricultural industries. Zinc oxide is used as a white pigment in watercolours or paints, and as an activator in the rubber industry. As a pigment, zinc is used in plastics, cosmetics, photocopier paper, wallpaper, printing inks etc, while in rubber production its role is to act as a catalyst during manufacture and as a heat disperser in the final product. Zinc metal is included in most single tablet, it is believed to possess anti-oxidant properties, which protect against premature aging of the skin and muscles of the body. Zinc is also a necessary element for proper growth and development of humans, animals, and plants; it is the second most common trace metal, after iron, naturally found in the human body. [2, 5]

Handling considerations

Precautions for safe handling: Avoid raising dust. Keep away from naked flames/heat. Observe strict hygiene.

On (re)melting down: dry and preheat installation before use. Add only dry material to the metal bath.
Conditions for safe storage, including any incompatibilities:
Safe storage requirements:
Meet the legal requirements. Store in a dry area. Keep at temperature above dew point. Temperature above dew point.
Keep away from: (Strong) acids  [1]

PHYSICO-CHEMICAL PROPERTIES

Molecular weight                                  

65.38 g/mol  [2]

Bulk density/Specific gravity

6.9 g/cm3 (in powder form) [1]

7.1 g/cm3 (in particulate form) [1]

pH

Particle size

EC

Melting point

409°C in air (zinc powder) [1]

416°C in air (cast zinc particles) [1]

Boiling point

907 °C [2]

Flash point

Flammability

Highly flammable (zinc dust) [2], Auto-ignition: 460 °C [2]

Vapour density

Vapour pressure

Solubility in water

0.1 mg/L at 20°C [1]

zinc dust: insoluble in water [2]

Solubility in organic solvents

Solubility in inorganic solvents

Hydrolysis

According to Annex IX of REACH Regulation, information on hydrolysis is not required for inorganics [1]

Ionicity in water

Surface tension

Dispersion properties

Specific surface

Stability and reactivity

Chemical stability

Stable in dry air; becomes covered with white coating of basic carbonate on exposure to moist air. [2]

Reactivity hazards

Strongly electropositive; zinc foil will ignite in the presence of moisture. [2]

Zinc reacts violently with oxidants and powdered sulfur causing fire and explosion hazards. [2]

When heated to decomposition it emits toxic fumes of zinc oxide. [2]

Corrosivity

Polimerization

Incompatibility with various substances

Special remarks on reactivity

Soluble in acids and alkalies [2]

Slowly attacked by H₂SO₄ or HCl; oxidizing agents or metal ions (e.g., Cu2+, Ni2+, Co2+) accelerate the process; reacts slowly with ammonia water and acetic acid; rapidly with HNO3; reacts with alkali hydroxides to form "zincates", (ZnO2)2-, which are actually hydroxo complexes, such as (Zn(OH)3)-, (Zn(OH)4)2-, ((Zn(OH)4(H2O)2))2-   [2]

Zinc is attacked by carbon dioxide & sulfur dioxide resulting chiefly in a coating of hydrated basic carbonate of variable composition; hydrogen peroxide may be formed in the process. [2]

Physical, chemical and biological coefficient

Koc

Kow

pKa

log Kp

Freshwater: solid particulate matter and water (Kp_susp): 5.04 (log value)

Sediment (Zn): Kp_sed : 73.000 l/kg. (ECB 2008)

Marine water: Kp_{water/suspended matter}: 6010 l/kg

Soil: Kp_solids-water: 158.5 l/kg (log value 2.2)  [1]

Henry-constant

ENVIRONMENTAL FATE AND BEHAVIOUR

Artificial pollution sources

Zinc occurs naturally in air, water and soil, but zinc concentrations are rising unnaturally, due to addition of zinc through human activities. Most zinc is added during industrial activities, such as mining, coal and waste combustion and steel processing. [5]

Emissions to air, water and soil can occur at all stages of production and processing of zinc, particularly from mining and refining of zinc ores, and from galvanising plants. Sewage treatment plants and waste sites for industrial and household wastes can be sources of zinc levels harmful to the environment. Corrosion of galvanised structures can release zinc into soil and water. Uncontrolled release from application of fertilisers or herbicides may be possible. Wear and tear of car tyres and fuel combustion can contribute to elevated levels of zinc in roadside dust. [6]

General terrestrial fate

Zinc attaches to soil and sediment particles and most of the zinc will stay bound. Some zinc will move into the ground water and into lakes, streams, and rivers where it combines with other organic or inorganic matter. [6]

General aquatic fate

Zinc can be transported as dissolved compounds in natural waters. [6]

General atmospheric fate

Zinc can be transported as particles released into the atmosphere. Zinc attaches to dust particles in the air which settle to the ground or are taken out of the air by rain. [6]

General persistence and degradability

Abiotic degradation and metabolites

Biodegradation and metabolites

Bioconcentration

Volatilization

Photolysis

Hydrolysis

Soil adsorption and mobility

ENVIRONMENTAL CONCENTRATIONS

Measured data

 The content of Zn in natural (unfertilized and uncontaminated) soil is related to the chemical composition of the parent rock and the extent of weathering processes. The natural zinc content of soils is estimated to be 1–300 mg/kg. In the magmatic rocks it ranges from 40 to 120 mg/kg whereas in the sedimentary rocks its contents vary from 80 to 120 mg/kg in argillaceous sediments and shales to only 15–30 mg/kg in sandstones and 10–25 mg/kg in limestones and dolomites. [7]

In natural surface waters, the concentration of zinc is usually below 10 μg/litre, and in groundwaters, 10–40 μg/litre [8]. In tapwater, the zinc concentration can be much higher as a result of the leaching of zinc from piping and fittings [9].

ECOTOXICOLOGICAL INFORMATION

General adverse effects on ecosystem

Acute toxicity (LC50, EC50)

Aquatic systems

 LC50 (fish) at neutral/high pH low hardness: 0.169 mg Zn/l (Oncorrhynchus Mykiss) [1]

LC50 (fish) at low pH,  high hardness: 0.780 mg Zn/l (Pimephales promelas) [1]

LC50 (fish) at neutral/high pH, high hardness: 0.330 mg Zn/l (Pimephales promelas) [1]

EC50 (aquatic invertebrates) Ceriodapnia dubia:

EC50: 0.413 mg Zn/l at low pH and low hardness

EC50: >0.53 mg Zn/l at high pH and low hardness

EC50: 0.147 mg Zn/l at neutral/high pH and low hardness

EC50: 0.228 mg Zn/l at neutral/high pH and high hardness  [1]

Freshwater algae (Selenastrum capricornutum) IC50: 0.136 mg Zn/l (neutral/high pH [1]

Terrestrial systems

Chronic toxicity (NOEC, LOEC)

Aquatic systems

Freshwater: Data on 13 species available. NOECs: 0.037-0.400 mg Zn/l (dissolved concentrations) (Aquatic invertebrates)
Marine: Data on 26 species available. NOEC: 0.0056-0.9 mg Zn/l (dissolved concentrations) (Aquatic invertebrates) [1]

Freshwater: Data on 7 species available. NOECs: 0.044-0.530 mg Zn/l (dissolved concentrations) (fish)
Marine: Data on 1 species available. NOEC: 0.026 mg Zn/l (dissolved concentrations) (fish)  [1]

Freshwater algae (Pseudokircherniella subcapitata=Selenastrum capricornutum), NOEC: 0.019 mg Zn/l  [1]

Marine algae: NOEC: 0.0078-0.67 mg Zn/l  [1]

Multi-cellular algae species, NOEC: 0.06 mg Zn/l  [1]

Higher aquatic plant species, NOEC >0.65mg Zn /l [1]

Terrestrial systems

Worms: 37 NOEC or EC10 values cover 6 different worm species and vary from 35.7 mg Zn/kg for Enchytraeus albidus to 1634 mg Zn/kg dw for Lumbricus terrestris . [1]

Arthrophodes: Twenty-four NOEC/EC10 values are available for toxicity of Zn to reproduction of terrestrial arthropods, representing 2 different species and ranging between 14.6 and 1000 mg Zn/kg dw (both for Folsomia candida). [1]

Plants: NOEC and EC10 values vary between 32 mg Zn/kgdw for Trifolium pratense and Vicia sativa to 5855 mg Zn/kg dw for Triticum aestivum. [1]

All toxicity data are expressed as added Zn concentration in soil, based on either the nominal dose added or on measured, background corrected soil Zn concentrations.

HUMAN HEALTH EFFECTS and PROTECTION

Routes of human exposures

 inhalation, dermal contact, eye contact, ingestion

General effects

Even though zinc is an essential requirement for a healthy body, too much zinc can be harmful. Excessive absorption of zinc can also suppress copper and iron absorption. The required daily intake for adult humans is about 15 mg/day. The average dietary zinc intake in adults is 14-20 mg/day and is thus sufficient for nutritional needs. The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish.  [2]

Endocrine disruption

Mutagenicity

Carcinogenicity

No adequate experimental animal studies are available to evaluate the carcinogenicity of zinc compounds in humans [1]

Reprotoxicity

Teratogenicity

Under the conditions of the test, administration of up to 88 mg/kg bw of unspecified zinc sulphate (ca. 35.2 mg or 19.9 mg Zn2+/kg bw, for anhydrate and heptahydrate, respectively) had no adverse effects on adult hamsters and their foetuses.

Skin, eye and respiratory irritations

Key studies demonstrate a lack of irritation/corrosion potential [1]

No acute skin symptoms expected. Eye symptoms: redness. Inhalation symptoms: Cough. [2]

Metabolism:

absorption, distribution & excretion

Ingestion symptoms: Abdominal pain. Nausea. Vomiting. [2]

Exposure limits

 Regulatory OSHA PEL (Permissible Exposure Limit): 15 mg/m3 (Zinc oxide dust)

Calculated OSHA PEL, 8-hour TWA (Time weighted average): 10 mg/m3 (Zinc oxide dust)
NIOSH REL (Recommended Exposure Limit), up to 10h TWA (Time weighted average): 5 mg/m3, (C) Ceiling limit: 15 mg/m3  (Zinc oxide dust) [3]

National Board of Occupational Safety and Health, Sweden (1993): 8-hour TWA: 5 mg/m3 (Zn oxide fumes) [4]

Denmark: 8-hour TWA: 4 mg/m3 (Zn oxide fumes) [4]

Denmark: 8-hour TWA: 10 mg/m3 (Zn oxide dust) [4]

Drinking water MAC

Other information

Animal toxicity data

Acute toxicity (LD50)

  LD50>2000 mg/kg bw (oral, rat)  [1]

  LC50 > 5.41 mg/L/4h (inhalation, rat) [1]

  LD50: 630 mg/kg ( oral, rats) [2]

Chronic toxicity (NOEL, LOEL)

ENVIRONMENTAL STANDARDS AND REGULATIONS

EINECS regulation

̵listed on EINECS (European INventory of Existing  Commercial chemical Substances) List

OSHA regulations etc.

OTHER INFORMATION, SPECIAL REMARKS

Classification and proposed labelling with regard to toxicological data

Aquatic acute 1: 
H400: Very toxic to aquatic life.

Aquatic chronic 1:
H410: Very toxic to aquatic life with long lasting effects

Signal word: Danger

CREATED, LAST UPDATE

Created

2019. 04. 04.

Last update

2019. 04. 10.

REFERENCES

 [1] ECHA, European Chemical Agency, https://echa.europa.eu/hu/registration-dossier/-/registered-dossier/16146/1 Accessed: 2019.04.04-04.09.

 [2] Pubchem ZINC Dust (Compound), https://pubchem.ncbi.nlm.nih.gov/compound/zinc#section=Chemical-and-Physical-Properties   Accessed: 2019.04.09

 [3] United States Department of Labour, Occupational Safety and Health Administration, https://www.osha.gov/dsg/annotated-pels/tablez-1.html Accessed: 2019.04.09

[4] European Union Risk Assessment Report, ZnO, EUR 21171 EN https://echa.europa.eu/documents/10162/cc20582a-d359-4722-8cb6-42f1736dc820, Accessed: 2019.04.09

 [5] Lenntech. Water treatment solutions. https://www.lenntech.com/periodic/elements/zn.htm,  Accessed: 2019.04.10

 [6] Natural Pollutant Inventory, Australian Government, Department of the Environment and Energy. Fact sheets. Zinc and compounds. http://www.npi.gov.au/resource/zinc-and-compounds, Accessed: 2019.04.10

 [7] Noulas Ch., Tziouvalekas M., Karyotis Th. (2018) Zinc in soils, water and food crops, Journal of Trace Elements in Medicine and Biology 49 (2018) 252–260, https://doi.org/10.1016/j.jtemb.2018.02.009

[8] Elinder CG. (1986) Zinc. In: Friberg L, Nordberg GF, Vouk VB, eds. Handbook on the toxicology of metals,

2nd ed. Amsterdam, Elsevier Science Publishers, 1986:664-679.

[9] Nriagu JO (1980) ed. Zinc in the environment. Part I, Ecological cycling. New York, NY, John Wiley.