Mercury has many applications in industry due to its unique properties, such as its fluidity, its uniform volume expansion over the entire liquid temperature range, its high surface tension, and its ability to alloy with other metals (ATSDR, 1999). The amount of mercury and mercury compounds used has declined as less toxic and ecotoxic alternatives have replaced uses, including in medicine, agricultural compounds, preservatives, batteries, chemical processes, cosmetics etc (ATSDR, 1999; AICIS, 2015a and 2015b). Occupational exposure to mercury and mercury compounds can occur during production, storage, transportation, end-use, and disposal. Workers can be exposed to mercury and mercury compounds via inhalation, and eye and skin contact. Elemental mercury, and some other mercury compounds, can exist in the workplace as vapour as well as liquid (ATSDR, 1999).
Mercury, commonly called quicksilver, is a heavy, mobile liquid metal and is slightly volatile at room temperature. The vapour is readily absorbed through the lungs. Sources of mercury include metallic vapours, mercury salts and the more toxic organic mercury compounds. Metallic mercury (used in gold mining) is particularly dangerous due to mercury vapour being absorbed via the respiratory tract. This danger is increased further when the mercury is heated.
Mercury and its inorganic salts are used in a variety of ways. These include disinfectants, antiseptics and insecticides, and in scientific instruments and processes. Mercury is also used for extracting gold and silver from ores. Organic mercurials are found as antifungal preparations. A continuing source of exposure to mercury which has become a cause for concern is that of dental nurses who use amalgams for fillings in teeth. However, due to advances in dental surgery hygiene and the use of different types of fillings, this is not as significant a problem as it was 15 years ago. Methyl mercury, which is highly toxic, is found in fish and is a major cause for concern in badly polluted waters.
Mercury and its salts can enter the body by inhalation, oral ingestion or absorption. Mercury vapour cannot be absorbed through intact skin but many mercurial compounds can be. It is very toxic and cumulative. In the blood inorganic mercury is found equally in the plasma and red cells, while the alkyl compounds, such as methyl mercury, are concentrated ten to twenty fold in the red cells. The main target organs for mercury are the central nervous system and the kidney. Mercury is excreted in the urine (inorganic and metallic)and faeces(organic) and has a half life in the body of about 70 days. Increased exposure intensifies the symptoms.
Low grade continuous exposure can lead to:
• Inflammation of the mouth, soft gums, loose teeth, excessive salivation, metallic taste and foul breath.
• Tremor (hatter's shakes), particularly when the person is being observed or is in an unfamiliar environment or job.
• Mental and nervous symptoms including behavioral changes, stammering, anxiety, loss of sleep and loss of energy and drive.
• Increased exposure intensifies the symptoms
Sample timing is not critical for occupational exposure. Urine mercury is the recommended sample type for occupational monitoring.
Send to separating if ambient on arrival. Send to trace metals if frozen on arrival.
Aliquot to Core laboratory for UCRN
A random urine sample is taken into a sterile container and frozen as soon as possible to prevent loss of mercury due to bacterial contamination. Ensure that hands are washed and clothes are free of contamination. Sampling time is not critical
A 20 mL random urine sample is taken into a sterile container and frozen as soon as possible to prevent loss of mercury due to bacterial contamination. Ensure that hands are washed and clothes are free of contamination. Sampling time is not critical
The reported manifestations of subacute mercury poisoning are primarily neurological, with tremors, vertigo, irritability, moodiness and depression. They are associated with salivation, stomatitis and diarrhoea.
Random urines should be frozen if a delay of more than 48 hours until its received in the lab.
Reports issued by Canterbury Health laboratories will have results along with current Normal population Reference Intervals (RI).
For interpretation against Biological exposure indexes (BEI) please refer to the latest Worksafe’s : Biological Exposure Index (BEI) review.
See link in “Additional Information” tab below for Workplace Exposure Standards on the Worksafe.govt.nz website
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