Effects of PCB exposure on biochemical and hematological findings in capacitor workers.

Abstract

Certain former operations in capacitor manufacturing resulted in extensive direct contact of the workers with electrical grade polychlorinated biphenyls (PCBs). A study group of 194 such individuals, all exposed to Aroclor 1016 and many previously exposed to Aroclors 1242 and/or 1254, was examined before (1976) and after (1979) discontinuance of PCB use in the operations (1977). At the two examinations, the approximate geometric mean serum levels (in ppb) and 5 to 95% ranges were for lower PCBs (LPCB), 363 (57-2270) and 68 (12-392); and for higher PCBs (HPCB), 30 (6-142) and 19 (4-108), respectively.The statistical associations among 42 measured clinical chemical and hematological parameters, five different measures of PCB exposure, and seven confounding variables observed in the two examinations were determined by three regression procedures. Similar regressions were performed with DDE, which was present at background levels. The principal statistical findings were a depression in serum bilirubin and elevations in serum GGTP and lymphocyte levels at the time of the first examination, and only an elevation in monocytes at the second. Appraisal of the results suggested an induction of microsomal enzymes which appeared to be subsiding after the cessation of direct exposure to PCBs. The statistical association between serum levels of PCBs and lipids reported by others was confirmed, but shown to be explained by the partitioning behavior of PCB in the body, rather than to changes in liver function. No evidence for health impairment related to PCBs was found, despite the high serum levels of PCBs in the study population.

Estimating the half-lives of PCB congeners in former capacitor workers measured over a 28-year interval

“…The weights for each job then were multiplied by how long the participant worked in that job, and the results were summed over all jobs to estimate total cumulative occupational exposure to PCBs for each participant. Occupational exposure was also partitioned according to the years when specific Aroclors were used by GE, that is, 1946-1953for Aroclor 1254, 1953-1971for Aroclor 1242, and 1971-1977 for Aroclor 1016 (with minor Aroclor 1221 usage) (Lawton et al, 1985).…”

“…Areas surrounding the plant had an average air PCB concentration of 6.2 mg/m 3 (Taylor et al, 1991), whereas ambient air concentrations in urban areas distant from the plants averaged 0.1 mg/m 3 (Kutz and Yang, 1975). Fischbein et al (1979) analyzed sera from 310 workers in these facilities in 1976 and found that they were, on average, 10-to 20-fold higher than in the general population (Wolff et al, 1982;Lawton et al, 1985). A subgroup of our cohort also had sera archived from 1976, allowing us to compare PCB concentrations and estimate their half-lives over a 28-year period.…”

“…These differences in estimated half-lives between the two studies most likely reflect the longer time period over which we were able to estimate halflives. Indeed, it has been shown that serum PCB concentrations decay in a non-linear, at least two-component, pharmacokinetic manner with the greatest decreases occurring shortly after exposure (Yakushiji et al, 1984;Lawton et al, 1985;Phillips et al, 1989b). Thus, for the PCB congeners with long half-lives, the half-lives estimated over the shorter interval (3.8 years) used by Wolff and co-workers would have emphasized this earlier and more rapid decline in serum PCBs, and therefore may be responsible for their shorter estimates of half-lives.…”

Polychlorinated Biphenyls and Polybrominated Biphenyls

“…Fig. 1.9 shows ranges of air PCB concentrations in capacitor-manufacturing sites (Ouw et al, 1976;Bertazzi et al, 1982;Fischbein et al, 1982;Lawton et al, 1985;. The earlier concentrations (measured in the 1950s-1960s) were highest (Bertazzi et al, 1982), and decreased in later years.…”

“…In addition, PCB exposure during prenatal and early life has been associated with incidence of infectious and allergic diseases in children, and alterations in immune-system development. Lawton et al (1985) tested 194 workers exposed occupationally (152 men, 42 women) to one or more of the Aroclors 1254, 1242, and 1016 in a capacitor plant factory for an average duration of 17 years. The results taken in 1976 were compared with those from the same workers taken in 1979, two years after discontinuation of all PCB use in 1977.…”