Transcript mercury
Mercury Spills Marc Moss ENGR 435-001 November 24, 1998 Outline I. Facts II. Dangers III. Exposure IV. Clean Up V. Disposal VI. Questions Mercury Facts • Mercury is the most toxic non-radioactive element on earth • A silver colored mercury amalgam filling normally contains 52% mercury. • The typical adult carries ten amalgam fillings containing about 5 grams of mercury • 1/2 gram of mercury in a ten acre lake would warrant issuance of a fish advisory for the lake Dangers of Mercury The presence of raised mercury levels, in itself, does not necessarily cause pathologic reactions - the levels have to exceed a person’s threshold level. Dangers, continued Exposure in the range of 25 to 80 mg/m3 increases the incidence of: • defects in psychomotor performance • objectively detectable tremors • evidence of impaired nerve conduction • fatigue • irritability • loss of appetite • proteinuria Occupational Exposure Occupational exposure to 25 mg Hg / m3 air would correspond to a daily dose of somewhere about 100-200 mg / day (8 h / day, 5 days / week, 48 weeks / year, breathing of 1-2 m3 of air per hour containing 25 (80) mg Hg / m3 of which 80% is absorbed in the lung alveoli's). Concentrated Exposure Mercury can: • selectively inhibit protein and amino acid absorption into brain tissue • induce the thyroid gland to absorb an increasing amount of nuclear radiation from the environment • impair the adrenal and testicular steroid hormone secretions Exposure, continued • cause intolerance for stress and decreased sexual ability • in rats, it causes subnormal fertility and sperm production • produce contact dermititis •produce reduced function of the adrenal glands (Addison's disease), causing progressive anemia, low blood pressure, diarrhea and digestive disturbances Exposure, continued • cause chromosomal aberrations and alter the cellular genetic code • induce chromosomal breakage • alter cellular mitosis • cause a drop in T-cell production • kill white blood cells. •contribute to intelligence disturbances, speech difficulties, limb deformity, and hyperkinesia (hyperactivity resulting from brain damage) Exposure, continued Studies have been done that suggest elevated levels of mercury can trigger auto-immune disorders (MS, ALS, Alzheimer’s) Cleaning It Up • If available, use vacuum pump specifically designed for mercury spills • Sweep mercury into jar filled with water • Sprinkle area with sulfur powder or finely divided zinc and sweep up • Adhesive tape strips can be used for small spills Disposal The EPA has very strict restrictions on how to dispose of mercury. At UTC, the chemistry department will take the mercury, as they have procedures in place to handle it. DON’T THROW IT IN THE TRASH OR DOWN THE DRAIN!!!