ELEVATED SERUM LIVER-ENZYMES IN COKE-OVEN AND BY-PRODUCT WORKERS

Coke oven and byproduct workers are potentially exposed to coke oven e missions (COE), which contain hundreds of chemicals and are primarily composed of polycyclic aromatic hydrocarbons (PAH) and volatile organi c compounds. Some of these compounds are hepatotoxins. The objective o f this study was to examine the relationship between work in coke oven and by-product plants and serum activities of aspartate aminotransfer ase (AST) and alanine aminotransferase (ALT), the most commonly perfor med liver-function tests. The exposed group was composed of current wo rkers who had been employed at least 3 months in the two coke-operatio n work areas, including one coke oven plant and one byproduct plant (A rea I: n = 117; Area II: n = 96) of a large steel company in Taiwan. C ontrol subjects (Area III: n = 131), not visiting either coke-operatio n area in the last 3 months, were collected from the administrative an d nonproduction areas in the same company. PAH exposure, as a surrogat e of COE, was measured monthly by PM-10 size-selective high-volume-are a air samplers in or around these three areas between June and Decembe r 1990, as well as between November 1992 and June 1993. The mean total respiratory particulate PAH exposure levels (< 10 mu m) between Novem ber 1992 and June 1993 in Areas I, II, and III were 6.8 x 10(3), 2.1 x 10(3), and 6.5 x 10(1) ng/m(3), respectively. AST, ALT, and hepatitis B surface antigen tests were performed in 1994. Workers who showed ei ther AST or ALT levels greater than reference levels (abnormal > 25 IU /L) were regarded as showing ''elevated liver enzyme levels. ''Workers in Area I had AST levels that were 17 % higher (95 % confidence inter val [CI], 3 % to 32 %]) and ALT levels that were 35 % higher (95 % CI, 10 % to 65 %)] than those in Area III after controlling for appropria te confounders. The adjusted odds ratio (Area I vs Area III) for eleva ted liver enzymes was 4.4 (95 % CI, 1.5 to 13.4). In addition, coke ov en (n = 91) and by-product workers (n = 26) from Area I had ALT levels 37 % and 45 % higher, respectively, compared with control subjects fr om Area III, after adjusting for appropriate confounders. Similar effe cts are also seen for AST. Workers in Area II had slightly, but not si gnificantly, elevated AST and ALT levels. These results indicate that workers most heavily exposed to COE exhibit elevated aminotransferase levels.