In a lead pipe factory, you want to carry a screening programme in workers to exclude lead poisoning. Your choice of the most useful screening test will be measurement of:

In an automobile manufacturing plant of Pakistan, a large number of employees are working in different sections. Persons who work in the section of welding the parts together have started reporting sick with redness of eyes. On examination conjunctivitis and keratitis are foun What could be the cause of this problem?