POLYCYCLIC AROMATIC HYDROCARBONS (PAHs): A POSSIBLE CAUSE OF LUNG CANCER MORTALITY AMONG NICKEL/COPPER SMELTER AND REFINERY WORKERS

Abstract

A retrospective industrial hygiene investigation was undertaken to explain the cause of a statistically significant excess lung cancer mortality observed in a subset of a large cohort of nickel workers involved in mining, smelting, and refining of nickel and copper in Ontario. The focus of this paper is to demonstrate how an industrial hygiene follow-up assessment of an epidemiologic finding can help to identify a likely cause. Polycyclic aromatic hydrocarbons (PAHs) alone or in association with particulate and gaseous contaminants (e.g., SO2) were likely the causative agents of the excess lung cancer observed among the lead welders, cranemen, and arc furnace workers of the copper refinery.

Unrecognized risks of nickel-related respiratory cancer among Canadian electrolysis workers

“…Within a copper-refinery subgroup with ≥25 years of work experience, lung cancer mortality was twice that expected (table 3) (13,29). Most of the excess, which was assumed to be work-related, was identified among workers from the tank-house, notably among lead welders and crane men, the latter handling electrodes from travelling cranes above the electrolytic tanks (29,34). a Four workers had furnace experience only, and 3 workers had furnace experience combined with ≤6 months in "non-dust" departments.…”

“…The presence or concentration of soluble nickel in the electrolyte (20 g/L) was not communicated, and its possible contribution to the cancer excess was not discussed, neither in the epidemiological articles (13,29,43) nor in the industrial hygiene report (34). The latter focused on PAH exposure.…”

“…For the CCCR, an industrial hygiene investigation focused on exposure to polycyclic aromatic hydrocarbons (PAH) arising from asphalt and tar covering of the tank-house floor (34). No data on nickel were provided except for a statement that nickel exposures were "relatively low" for lead welders.…”

Update of a meta-analysis on lung cancer and welding

“…On the basis of the detailed assessment, 20 papers were excluded according to the following systematic exclusion criteria: (i) if later updates were available (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), (ii) if it was a mortality statistic (21) and a cancer morbidity study was available (22), (iii) the papers republished data (23,24) that were already available elsewhere (25,26), (iv) the metal welded was atypical (lead) or the welders were resistence welders (27,28), and (v) the description of the welder population was insufficient (29).…”

Urinary metal and polycyclic aromatic hydrocarbon biomarkers in boilermakers exposed to metal fume and residual oil fly ash

“…We have shown that boilermakers are exposed to PAH and metals during the workweek, as indicated by repeated urinary sampling and measurement of 1-OHP and individual metal biomarkers of exposure. This is important because workers exposed to high levels of PAH, such as coke oven and aluminum industry workers, demonstrate an increased risk of cancer [IARC, 1983[IARC, , 1984[IARC, , 1985Bertrand et al, 1987;Verma et al, 1992]. Similarly, the carcinogenic potential of nickel and chromium has been well established for humans and experimental animals [IARC, 1990;Man, 1990;Hayes, 1997;Merzenich et al, 2001].…”