Evaluation of cumulative PCB exposure estimated by a job exposure matrix versus PCB serum concentrations

Abstract

Although polychlorinated biphenyls (PCBs) have been banned in many countries for more than three decades, exposures to PCBs continue to be of concern due to their long half-lives and carcinogenic effects. In National Institute for Occupational Safety and Health studies, we are using semiquantitative plant-specific job exposure matrices (JEMs) to estimate historical PCB exposures for workers (n = 24,865) exposed to PCBs from 1938 to 1978 at three capacitor manufacturing plants. A subcohort of these workers (n = 410) employed in two of these plants had serum PCB concentrations measured at up to four times between 1976 and 1989. Our objectives were to evaluate the strength of association between an individual worker's measured serum PCB levels and the same worker's cumulative exposure estimated through 1977 with the (1) JEM and (2) duration of employment, and to calculate the explained variance the JEM provides for serum PCB levels using (3) simple linear regression. Consistent strong and statistically significant associations were observed between the cumulative exposures estimated with the JEM and serum PCB concentrations for all years. The strength of association between duration of employment and serum PCBs was good for highly chlorinated (Aroclor 1254/HPCB) but not less chlorinated (Aroclor 1242/LPCB) PCBs. In the simple regression models, cumulative occupational exposure estimated using the JEMs explained 14-24% of the variance of the Aroclor 1242/LPCB and 22-39% for Aroclor 1254/HPCB serum concentrations. We regard the cumulative exposure estimated with the JEM as a better estimate of PCB body burdens than serum concentrations quantified as Aroclor 1242/LPCB and Aroclor 1254/HPCB.

PCB plasma level in different occupational groups in Iran

“…Correspondingly, dioxin-like PCB congeners with fewer (2-5) chlorine atoms, also known as "lower chlorinated PCBs," are considered to be more important than those with a higher number of chlorine atoms from a toxicological perspective (6-12), since these are markers of occupational exposure (Schettgen et al, 2011). Lower chlorinated PCBs have shorter half-lives, which are excreted faster than the higher chlorinated congeners (Hopf et al, 2014). On the other hand, the higher chlorinated biphenyls have a slower metabolism and higher stability, which are mostly stored in fatty tissues resulting in their accumulation in the food chain (Schettgen et al, 2011).…”

“…PCBs have been previously used for nominally closed applications such as capacitors and transformers and also as pesticide extenders and plasticizers for some open applications such as microencapsulation of paints and varnishes (Eisler, 2000;Fiedler, 2001;Henry and DeVito, 2003). Biological monitoring is known as the gold standard exposure metric for the cumulative burden of PCBs, including occupational and environmental exposures, because it can capture the effects of all routes of exposure (Hopf et al, 2014).…”

Quantification of Polychlorinated Biphenyl (PCB) Concentration in San Francisco Bay Using Satellite Imagery

“…Widespread concern over these adverse health risks prompted the U.S. Environmental Protection Agency (EPA) to ban the production of PCBs in 1979. However despite this nearly four decade-long production moratorium, PCBs, due in large part to their highly stable chemical structures, continue to persist in watersheds across the continental United States, often at concentrations considered hazardous to human health [2,3,[6][7][8].…”