Effects of occupational exposure to carbon black on peripheral white blood cell counts and lymphocyte subsets

Abstract

The International Agency for Research on Cancer has classified carbon black (CB) as a possible (Group 2B) human carcinogen. Given that most CB manufacturing processes result in the emission of various types of chemicals, it is uncertain if the adverse health effects that have been observed in CB-exposed workers are related to CB specifically or are due to other exposures. To address this issue, we conducted a cross-sectional molecular epidemiology study in China of 106 male factory workers who were occupationally exposed to pure CB and 112 unexposed male workers frequency-matched by age and smoking status from the same geographic region. Repeated personal exposure measurements were taken in workers before biological sample collection. Peripheral blood from all workers was used for the complete blood cell count and lymphocyte subsets analysis. Compared to unexposed workers, eosinophil counts in workers exposed to CB were increased by 30.8% (P = 0.07) after adjusting for potential confounders. When stratified by smoking status, statistically significant differences in eosinophils between CB exposed and unexposed workers were only present among never smokers (P = 0.040). Smoking is associated with alterations in various cell counts; however, no significant interaction between CB exposure and smoking status for any cell counts was observed. Given that inflammation, characterized in part by elevated eosinophils in peripheral blood, may be associated with increased cancer risk, our findings provide new biologic insights into the potential relationship between CB exposure and lung carcinogenesis. Environ. Mol. Mutagen. 57:589-604, 2016. © 2016 Wiley Periodicals, Inc.

Evaluating the evidence on genotoxicity and reproductive toxicity of carbon black: a critical review

“…Moreover, epidemiological evidence from carbon black production workers chronically exposed to carbon black has not shown consistent patterns of either an elevated risk of lung cancer or a dose-response trend [discussed in IARC (2010) and Dell et al (2015)]. Also, no association of carbon black exposure with inflammation markers (number of white blood cells, neutrophils, lymphocytes, T cells, CD4þ, CD8þ, B cells, NK cells, and monocytes) in blood of exposed workers was found in a recent epidemiological study (0.66 mg/m 3 elemental carbon, measured in personal samples from 8 packing workers); a borderline, possibly allergy-induced, increase in eosinophil count, was only significant in workers that have never smoked (Dai et al 2016). At an excessive workplace concentration of 14.90 mg/m 3 (measured by personal air samplers), however, increases in IL-1b, IL-6, IL-8, MIP-1beta, and TNFalpha were found (Zhang et al 2014).…”

Current state of knowledge on the health effects of engineered nanomaterials in workers: a systematic review of human studies and epidemiological investigations

“…In a subsequent investigation, the same group of researchers analyzed possible changes exerted by carbon black ENM-occupational exposure on hematological indices (21). Their results showed a significant increase Occupational health impact of engineered nanomaterials Primary size: 30-50 nm…”

Occupational exposure to carbon black nanoparticles increases inflammatory vascular disease risk: an implication of an ex vivo biosensor assay

“…Among the seven biosensor genes studied, ICAM, VCAM, CCL2, and CXCL8 expressions were identified to be dramatically induced by TNF-α treatment. Relative quantification ranged from 1.88 for CXCL8 to 3.05 for CCL2 per 500 pg/ ml addition of TNF-α in the culture medium major sources for generating TNF-α in circulation [24]. Study showed that in vitro treatment of alveolar macrophages with ambient urban particles and carbon black could induce particle phagocytosis and stimulate a dosedependent secretion of TNF-α in supernatant [27].…”

“…Because acetylene carbon black is almost pure elemental carbon [14], the summed level of urinary hydroxyl polycyclic aromatic hydrocarbons was not different between CBPs and non-CBPs. The average level of particulate matter with diameters of 2.5 μm or less (PM2.5) in carbon black bagging areas was 800.0 μg/m 3 with elemental carbon level at 657.0 μg/m 3 (Table 1) [14,24], well within the recommended long term exposure limit of carbon black (3.5-4 mg/m 3 ) in North America, European Union, and China [25]. Size distribution analysis of carbon black aerosol inside the bagging areas showed that up to 99.6% of the carbon black particles had aerodynamic diameter less than 2.5 μm with 96.7% of the particulates less than 1.0 μm [14].…”