A Study of Mortality in Workers Engaged in the Mining, Smelting, and Refining of Nickel: I: Methodology and Mortality by Major Cause Groups

Abstract

Following the publication of the NIOSH nickel criteria document in 1977, the Joint Occupational Health Committee of the International Nickel Company (INCO) commissioned a mortality study of the company's Ontario workforce. This paper describes the detailed methodology and primary mortality results of the ensuing study; subsequent papers will describe more detailed findings of cause-specific mortality. An historical prospective mortality study of approximately 54,000 INCO workers has been conducted. Men with six months or more of service were followed for mortality during a 35-year period by computerized record linkage to the Canadian National Mortality Data Base. From a company-provided list of men known to have died and through independent follow-up of a random sample of 1,000 subjects of unknown status, we estimate a mortality ascertainment rate of 95%. Cause-specific standardized mortality ratios calculated with respect to Ontario provincial mortality rates indicate an excess of accidental deaths in men working in the Sudbury area and an excess of cancer deaths at the company's Port Colborne nickel refinery. A strong healthy worker effect was found for both all-disease mortality ad cancer mortality. The lower than expected mortality persisted for about 15 years beyond initial hiring.

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

“…Loss to follow-up was less pronounced for the PCNR part of the cohort, as 42% had unknown vital status, and 80% of deaths were recorded in company records (48). On the other hand, a higher age of PCNR workers was suggested in the data (48), which may increase the risk of a downward bias. The bias may also be stronger for short-term workers, for whom the recognition of a death would be more dependent on a successful linkage to the National Mortality Database.…”

“…By 1976, 44% of the cohort was lost to followup in this way (28), rising to 57% in the last update through 1984, although somewhat lower (42%) for the PCNR fraction of the cohort (48). Deaths identified by linkage to the Canadian National Mortality Database only contributed some 30% of all deaths in the last study, implying that the proportion identified in company records was substantial.…”

“…The size of this potential downward bias was addressed in the 1984 study (28), and referred to in the subsequent update (48), by an attempt to trace individually 1000 men out of the 24 000 not found to be dead in company records. The results showed that 75 (7.5%) out of the 1000 men were completely lost to follow-up as a result of emigration or unknown reason despite reinforced efforts.…”

“…Still, the new cohort reported substantially fewer respiratory cancer deaths than the last update of the original cohort (table 2), indicating a marked loss of long-term workers (≥5 years) who were known from the earlier studies to have died from respiratory cancer. The mortality in the new cohort was addressed a second time based on an extended, overlapping observation period, published in four papers (13,29,43,48), whereof three -including that of the ICNCM -focused on respiratory cancer. Some study characteristics and overall results are summarized in table 2.…”

BIORREMEDIACION DE NIQUEL (II) EN SOLUCION ACUOSA POR Aspergillus niger GC1

“…En el medio ambiente, el níquel se encuentra principalmente combinado con oxígeno o azufre en forma de óxidos y sulfuros y puede formar complejos estables con la materia orgánica disuelta (Nieminen et al, 2007). Tanto al óxido como al sulfuro de níquel, se han asociado con cáncer de pulmón de los obreros de las refinerías de este metal (Roberts et al, 1989;Sarkar & Margules, 2002).…”