Biological impact of exposure to Mercury
Mercury is a dense, silvery metal used in thermometers,pressure gauges and for some chemical processes. Crude oil and natural gas can contain a variety of naturally occurring heavy metals such as mercury.
Elemental mercury, when present in the air poses an immediate health risk to refinery workers. It is poisonous in all forms and is a non specific toxin, attacking many of the body’s systems. At low levels of exposure, symptoms include memory loss, emotional changes including mood swings, irritability, nervousness and excessive shyness, insomnia, tremors and other stress-like symptoms: poor coordination, headache, visual and hearing problems. At high exposures there may be kidney effects and respiratory failure.
Occupations involving frequent mercury exposure include:
- Off shore oil workers
- Dentists, Doctors and Nurses
- Workers involved in recycling of electrical and electronic equipment
- Laboratory workers
Mercury can enter the body by:
- Ingestion of material containing mercury
- Absorption through the skin
Mercury absorbed into the body is excreted slowly in the urine, the concentration of mercury in urine reflects cumulative exposure over the previous 2-4 months. The level of mercury in urine samples responds to changes in exposure level slowly with time. Consequently, the level of mercury in urine samples will accurately reflect the overall level of mercury exposure, smoothing out day to day variations in intake.
The exposure limits for mercury levels in urine are expressed relative to the creatinine level, they are as follows:
- UK: 20ugmol/mol creatinine
- Germany: 14ugmol/mol creatinine