The role of biological monitoring in the health management of lead- exposed workers

In 1967, the problem of occupational lead exposure came to public attention in Korea. Since then, regular progress has been made in lowering workplace lead exposures, instituting new workplace controls, and implementing health examinations of exposed workers. Serious lead poisoning episodes led to the introduction of biological monitoring programs on a voluntary basis in high lead exposure facilities in Korea. Occupational health services for lead workers in Korea during the last 10 years could be categorized into three phases. During the first phase (1988-1993), effort was directed at increasing awareness among workers concerning the hazards of lead exposure, biological monitoring was commenced with zinc protoporyphin (ZPP), and a respiratory protection program was introduced. During the second phase (1994-1996), a computerized health management system of lead workers was developed, blood lead measurement was added for biological monitoring, and engineering controls were introduced in the workplace to lower air lead levels to comply with air lead regulations. Finally, during the third phase (1997-present), bone lead measurement by X-ray fluorescence was introduced to evaluate total body lead burden. During the period 1988-1998, air lead levels have remained generally steady and above the permissible exposure level (PEL), but ZPP and blood lead levels have shown a steady decline. It was discovered that in a developing country like Korea, which cannot introduce engineering controls quickly to protect lead workers, biological monitoring was very useful in identifying and lowering excess lead absorption. In the future, as average exposure duration continues to rise, bone lead measurement may be recommended to adequately protect the long-term health of lead workers.