Heavy Metal Toxicity - Universiti Putra Malaysia：重金属毒性-马来西亚博特拉大学.ppt

Lead Correlation between blood lead levels and clinical effects 40 ug/dl – usually none 40 – 80 ug/dl – mild symptoms 80 ug/dl – severe manifestation such as convulsions Lead Regulation, 1984 under FMA Action level Airborne concentration of 75 ug/m3 of air averaged over 8-hour period PEL in airbone 150 ug/m3 Lead Exposure monitoring Full shift personal samples, at least 1 sample per work area If below action level no further assessment needed unless there has been a change in production, process, control or personnel If at or above action level, should repeat every 6 months If at/above PEL, repeat every 3 months Medical surveillance For all workers exposed above action level for more than 30 days per year Biological monitoring At least every 6 months for exposed workers Every 3-months if blood Pb 40-60 ug/100 gm blood Monthly if 60-80, during removal period for female worker of child bearing capacity Lead – preventive measures Improvement of work process – elimination, substitution, enclosure, engineering control Work-place hygiene Appropriate PPE Appropriate signages Prevent childhood lead poisoning Engineering control equipment Local exhaust ventilation system Water spray to control dust or Airborne chemical removal and containment equipment Maintenance requirements During operational conditions Monthly inspection Annual examination and testing Record keeping Lead Control measures USCHH Regulation 15(2), (3) Safe work systems and practices Documented Implemented Reviewed if Changes to Process Equipment Materials and control measures PPE Part V, USCHH regulation 16 Impracticable application of control measures a to g As an interim measure Control measures are not adequate Test used to identify lead poisoning Blood lead Heme metabolism Pb inhibits delta-amino-levulinic acid dehydratase (enzymes invovle in synthesis of porphyrins and heme) Inhibition of the enzymes result in accumulation of the substrate aminolevulinic acid (ALA) in blood or urine Nerve condu