Silver

2015-07-23

Silver is a chemical element with symbol Ag and atomic number 47. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining. [1]

Pure silver is nearly white, lustrous, soft, very ductile, malleable, it is an excellent conductor of heat and electricity. It is not a chemically active metal, but it is attacked by nitric acid (forming the nitrate) and by hot concentrated sulfuric acid. It has the highest electrical conductivity of all metals, but its greater cost has prevented it from being widely used for electrical purposes. Silver does not oxidise in air but reacts with the hydrogen sulfide present in the air, forming silver sulfide (tarnish). This is why silver objects need regular cleaning. Silver is stable in water. [2]

Uses [3]

Silver is used to make jewellery, silverware, electronic equipment, and dental fillings. It is also used to make photographs, in brazing alloys and solders, to disinfect drinking water and water in swimming pools, and as an antibacterial agent. Silver has also been used in lozenges and chewing gum to help people stop smoking.

Sources & Routes of Exposure

Sources of Exposure [3]

  • Breathing low levels in air.
  • Swallowing it in food or drinking water.
  • Carrying out activities such as jewellery making, soldering, and photography.
  • Using anti-smoking lozenges or other medicines containing it.

Routes of Exposure [4]

Silver’s wide variety of uses allows exposure through various routes of entry into the body. Ingestion is the primary route of entry for silver compounds and colloidal silver proteins. Inhalation of dusts or fumes containing silver occurs primarily in occupational settings. Skin contact occurs in occupational settings, from the application of burn creams and from contact with jewellery. Silver can also gain entry into the body through the use of acupuncture needles, catheters, dental amalgams, or accidental puncture wounds.

Health Effects [3]

  • Exposure to high levels of silver for a long period of time may result in a condition called arygria, a blue-grey discoloration of the skin and other body tissues. Argyria is a permanent effect, but it appears to be a cosmetic problem that may not be otherwise harmful to health.
  • Lower-level exposures to silver may also cause silver to be deposited in the skin and other parts of the body; however, this is not known to be harmful.
  • Eye contact: may cause severe corneal injury if liquid comes in contact with the eyes.
  • Skin contact: may cause skin irritation. Repeated and prolonged contact with skin may cause allergic dermatitis.
  • Inhalation hazards: exposure to high concentrations of vapours may cause dizziness, breathing difficulty, headaches or respiratory irritation. Extremely high concentrations may cause drowsiness, staggering, confusion, unconsciousness, coma or death.
  • Liquid or vapour may be irritating to skin, eyes, throat, or lungs. Intentional misuse by deliberately concentrating and inhaling the contents of this product can be harmful or fatal.
  • Ingestion hazards: moderately toxic. May cause stomach discomfort, nausea, vomiting, diarrhoea, and narcosis.
  • Aspiration of material into lungs if swallowed or if vomiting occurs can cause chemical pneumonitis, which can be fatal.
  • Animal studies have shown that swallowing silver results in the deposit of silver in the skin. One study in mice found that the animals exposed to silver in drinking water were less active than unexposed animals.
  • No studies are available on whether silver affects reproduction or causes developmental problems in people.
  • No studies are available on whether silver may cause cancer in people.
  • The only available animal studies showed both positive and negative results when silver was implanted under the skin.
  • The EPA has determined that silver is not classifiable as to human carcinogenicity.

Safety [5]

First Aid Measures

  • Eye Contact: Check for and remove any contact lenses. Do not use an eye ointment. Seek medical attention.
  • Skin Contact: No known effect on skin contact, rinse with water for a few minutes.
  • Inhalation: Allow the victim to rest in a well-ventilated area. Seek immediate medical attention.
  • Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek medical attention.
  • Ingestion: Do not induce vomiting. Examine the lips and mouth to ascertain whether the tissues are damaged, a possible indication that the toxic material was ingested; the absence of such signs, however, is not conclusive. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek immediate medical attention.

Exposure Controls & Personal Protection

Engineering Controls

  • Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits.
  • If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.

Personal Protective Equipment

The following personal protective equipment is recommended when handling silver:

  • Splash goggles
  • Lab coat

Personal Protection in Case of a Large Spill:

  • Splash goggles
  • Full suit
  • Boots
  • Gloves
  • Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product

Regulation [6,7]

United States

<b>Exposure Limit</b>

<b>Limit Values</b>

<b>HE Codes</b>

<b>Health Factors and Target Organs</b>

OSHA Permissible Exposure Limit (PEL) – GeneralIndustry
See
<a target="_blank"href="https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9992&p_text_version=FALSE">29CFR 1910.1000 Table Z-1</a>

0.01 mg/m3 TWA

HE3

Argyria

OSHA PEL – Construction Industry
See
29 CFR 1926.55 Appendix A

0.01 mg/m3 TWA

HE3

Argyria

OSHA PEL – Shipyard Employment
See <a target="_blank"href="https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10286&p_text_version=FALSE">29CFR 1915.1000 Table Z-Shipyards</a>

0.01 mg/m3 TWA

HE3

Argyria

National Institute for Occupational Safetyand Health (NIOSH) Recommended Exposure Limit (REL)

0.01 mg/m3 TWA

HE3

Argyria

HE4

Eye and skin burns

HE14

Eye and skin irritation

American Conference of GovernmentalIndustrial Hygienists (ACGIH) Threshold Limit Value (TLV)(2001)

Metal dust:
0.1 mg/m3 TWA

Soluble compounds:
0.01 mg/m3 TWA

HE3

Argyria

CAL/OSHA PELs

Metal:
0.01 mg/m3 TWA

Soluble compounds:
0.01 mg/m3 TWA

 

 

Australia

Safe Work Australia: Safe Work Australia has set a time weighted average (TWA) concentration of 0.01 mg/m3 for silver over a 40-hour workweek.

References

https://en.wikipedia.org/wiki/Silver

http://www.lenntech.com/periodic/elements/ag.htm

http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=538&tid=97

http://annhyg.oxfordjournals.org/content/49/7/575.full

http://www.sciencelab.com/msds.php?msdsId=9927253

http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/772/Workplace-exposure-standards-airborne-contaminants.pdf