Effect of Söderberg Smelting Technology, Anode Paste Composition, and Work Shift on the Relationship Between Benzo[a]pyrene and Individual Polycyclic Aromatic Hydrocarbons

ABSTRACT

This follow-up study of Farant and Gariepy study investigates the relationship between benzo[a]pyrene (B[a]P) and other polycyclic aromatic hydrocarbons (PAHs) found in coal tar pitch volatiles in two types of Söderberg aluminum smelters—horizontal and vertical stud. The study confirms the strong relationships between B[a]P and total PAHs, and that B[a]P was a good indicator for other PAHs in this industry. The PAH profiles were consistent within each smelter, but the smelter technology used and the changes in the raw material formulation resulted in significantly different profiles. B[a]P toxic equivalency factors for emitted PAH mixtures were greater in the horizontal stud smelter than in the vertical stud smelter. Overall, this study illustrates the potential usefulness of B[a]P relative abundance ratios to simplify exposure assessment in the workplace and reduce associated costs.

Keywords:

• aluminum smelter
• benzo[a]pyrene
• polycyclic aromatic hydrocarbons
• relative abundance ratios

ACKNOWLEDGMENTS

The authors would like to thank all individuals at both aluminum smelters for the technical support needed to realize and complete the sampling campaigns. The authors would especially like to thank Richard Lapointe from Alcan Inc., for his comments and the administrative support needed to complete this study.

Notes

^A Matched samples above the electrolytic cells for day and night shift.

^A Pearson correlation coefficient.

^B Volatile PAH: primarily present in the gaseous phase.

^C Semivolatile PAH: present in both the volatile and particulate phase.

^D Particulate PAH: primarily present in the particulate phase.

^E PAH not measured during May 2002 campaign.

^F PAH not measured during August 2001 campaign.

^A Arithmetic mean.

^B Coefficient of variation.

^C Significant differences (p < 0.05) in bold for B[a]P RARs between HSS and VSS smelters.

^A Matched samples for day shift (n = 12) and night shift (n = 12) above individual pots.

^B Nonmatched (random) samples for day shift (n = 6) and night shift (n = 6) outside cranes.

^C Arithmetic mean.

^D Coefficient of variation.

^E Significant differences (p < 0.05) in bold for B[a]P RARs between day and night shifts.

^A B[a]P RAR X B[a]P relative potency factor.

^B Source: Willes et al. ⁽¹⁵⁾