Search

Aims Unintentional nanoscale particles (UNP) are generated from usual work processes and thus exist since a long time and are more prevalent than the manufactured nanoscale particles. The objective of this study was to develop a job-exposure matrix, a useful tool to estimate prevalence of occupational exposure to UNP for epidemiologic studies. . Methods Work-processes generating UNP and their associated chemical families have been identified through an extensive literature review and the knowledge of an expert’s panel in various domain such as industrial hygiene, toxicology, atmospheric physics and chemistry, epidemiology… These processes were associated to occupations extracted from the ISCO classification edition 1968. A probability and a frequency were assessed for each specific combination “occupation × work-process”. When an occupation was related to several work-processes, the final exposure assessment consisted in the highest probability of exposure and a weighted-frequency of exposure combining assessments from each related work-process. Exposure assessment for some specific occupations could differ according to industries and historical periods. Due to the few available measurement data, intensity could not be assessed at that time. Results Over 50 work-processes generating UNP have been identified and were related with seven UNP chemical families: metal, mineral, carbon, wood, polymer, polycyclic aromatic hydrocarbon (PAH) and other organic. A little less than 50% occupational ISCO codes were unexposed, and 9%, 13% and 31% were possibly, probably and certainly exposed, respectively. Most of occupations were exposed to carbonaceous, PAHs UNP and then to metallic and mineral UNP. Conclusions These results suggest that occupational exposure to UNP might be important at the workplace and might concern a wide variety of workers. In order to assess intensity of exposure, we are currently organising measurement campaigns in French and Canadian workplaces (ExproPNano program).

Introduction Nanoscale particles (1-100 nm) may be naturally occurring; intentionally-produced for commercial purposes or unintentionally-produced by manufacturing processes or human activities. Toxicological data have suggested a possible carcinogenic effect of nanoscale particles and have shown that they have the ability to translocate into different organs including the brain. While epidemiological data on nanoscale particles are very scarce to date, there is some suggestion of their potential role in cancer (e.g. diesel exhaust emissions classified as carcinogenic for humans by IARC). The objective of this study was to estimate the association between occupational exposure to nanoscale particles and risk of brain tumour in adults. Methods The CERENAT study is a multicenter case-control study carried out in four districts of France between 2004 and 2006. From detailed occupational histories, occupational exposure to unintentionally-produced nanoscale particles was retrospectively assessed by the MatPUF job exposure matrix providing a probability and frequency of exposure for each combination occupation × industry according to international and national classifications. Conditional logistic regression was used to estimate ORs and 95% CIs. Results Overall, 596 brain tumour cases and 1192 matched controls were included in this study. Among men, a significant association between occupational exposure to nanoscale particles and brain tumour was observed (OR = 1.5; 95% CI: 1.1–2.2). This increased OR was essentially observed in the highest exposure categories (OR = 1.6; 95% CI: 1.1–2.4 for a total duration of exposure over 30 years) as well as for carbonaceous (OR = 1.5; 95% CI: 1.1–2.3) and HAP nanoscale particles (OR = 1.6; 95% CI: 1.1–2.4). Conclusion Even if these preliminary results should be confirmed by other analyses including the intensity of exposure (on-going work in a further version of the job-exposure matrix), these results should encourage further epidemiological research on nanoscale particles.