EXPOSURE OF WORKERS TO 2,3,7,8-SUBSTITUTED POLYCHLORINATED DIBENZO-P-DIOXIN (PCDD) AND DIBENZOFURAN (PCDF) COMPOUNDS IN SAWMILLS PREVIOUSLYUSING CHLOROPHENOL-CONTAINING ANTISTAIN AGENTS

The use of chlorophenol-containing antistain agents (e.g., Ky5, a wood presentative) ceased in Finland at the end of the 1980s, after 5 deca des of use. Exposure of workers to the impurities in these agents (i.e ., polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs] ) was assessed at three sawmills at which personnel used a sodium chlo rophenate product as an antistain agent. Given that compounds accumula te in body fat and their half-lives in humans are long, we could deter mine 2,3,7,8-substituted PCDDs and PCDFs 5-9 y after the last exposure occurred. We used high-resolution gas chromatography/high-resolution mass spectrometry to determine PCDDs/PCDFs in plasma from 39 Ky5-expos ed workers and 18 nonexposed workers. The average total plasma concent ration of PCDD/PCDF of the Ky5-exposed workers at the three sawmills w ere 1 018, 945, and 1 165 pg/g fat, and corresponding concentrations i n the nonexposed workers were 743, 1 124, and 844 pg/g fat, respective ly. We found no significant differences in total levels between Ky5-ex posed workers and nonexposed workers. However, concentrations of the 1 ,2,3,4,6,7,8-HpCDF isomer were significantly higher ip (p<.01) among t he Ky5-exposed workers at all three sawmills (averages of 224, 99, and 148 pg/g fat) than among their respective nonexposed workers (average s of 43, 48, and 44 pg/g fat). These results indicate that workers had handled Ky5. When we expressed concentration levels in international toxic equivalents (I-TEQs), the mean total I-TEQ PCDD/PCDF of Ky5-expo sed workers was significantly lower at one of the sawmills (average = 42 pg I-TEQ/g) than at the other two sawmills (averages of 64 and 62 p g I-TEQ/g)(p <.05). Nevertheless, total concentrations at the sawmills studied were within the range of background levels in the general pop ulation.