Assessing the chronic respiratory health risk associated with inhalation exposure to powdered toner for printing in actual working conditions: a cohort study on occupationally exposed workers over 10 years

Challenges in Diagnosing Occupational Chronic Obstructive Pulmonary Disease

Occupational chronic obstructive pulmonary disease (oCOPD) represents 15–20% of the global burden of this disease. Even if industrial bronchitis has long been known, new occupational hazards continue to emerge and enlarge the number of people exposed to risk. This review discusses the challenges related to the early detection of oCOPD, in the context of new exposures and of limited usage of methods for an efficient disease occupational screening. It underlines that a better translation into clinical practice of the new methods for lung function impairment measurements, imaging techniques, or the use of serum or exhaled breath inflammation biomarkers could add significant value in the early detection of oCOPD. Such an approach would increase the chance to stop exposure at an earlier moment and to prevent or at least slow down the further deterioration of the lung function as a result of exposure to occupational (inhaled) hazards.

Challenges and Emerging Trends in Toner Waste Recycling: A Review

Toner waste is one of the major electronic waste materials posing serious environmental threat and health hazards. Globally, only about 20–30% of toner waste is recycled, while the remaining percentage is dumped in landfills. Recycling options are limited due to the desirably engineered durability of toners, ascribed to a complicated composition of chemicals, carbon black, and plastic particles, which in turn creates critical challenges in recycling. The World Health Organization has classified toner waste as class 2B carcinogen due to its potential health hazard. In this review, the existing challenges in toner waste recycling are discussed from the perspective of environmental, health, and feasibility aspects. In parallel, the challenges have been opening up alternative strategies to recycle toner wastes. Emerging trends in toner waste recycling include transformation of toner waste into value-added products, utilization as raw material for nanomaterial synthesis, generation of composite electrodes for power generation/storage devices, integration into construction materials, and development of microwave absorbing composites. Considering the enormous volume of toner waste generated globally every year, better recycling and transformation strategies are needed immediately. A circular economy could be established in the future by transforming the enormous toner waste into a resource for other applications. For an effective management of toner waste in the future, an integrated approach involving policies and legislations, infrastructure for collection and treatment, and financial planning among the stakeholders is needed in addition to technological innovations.

Release and cytotoxicity screening of the printer emissions of a CdTe quantum dots-based fluorescent ink

The fluorescent properties of cadmium telluride (CdTe) containing quantum dots (QDs) have led to novel products and applications in the ink and pigment industry. The toxic effects of the emissions associated to the use of printing ink containing CdTe QDs might differ from those of conventional formulations which do not integrate nanoparticles, as CdTe QDs might be emitted. Within this work, the airborne emissions of a water-soluble fluorescent ink containing polyethylene glycol (PEG)-coated CdTe QDs of 3-5 nm diameter have been characterized and studied under controlled conditions during household inkjet printing in a scenario simulating the use phase. Subsequently, the cytotoxicological potential of atomized CdTe QDs ink in an acute exposure regimen simulating an accidental, worse-case scenario has been evaluated in vitro at the air-liquid interface (ALI) using the pulmonary cell line BEAS-2B. Endpoints screened included cell viability, oxidative stress and inflammatory effects. We have observed that CdTe QDs ink at 54.7 ng/mL decreased cell viability by 25.6 % when compared with clean air after 1h of exposure; a concentration about 65 times higher was needed to observe a similar effect in submerged conditions. However, we did not observe oxidative stress or inflammatory effects. The present study integrates the development of scenarios simulating the use phase of nano-additivated inks and the direct cell exposure for in vitro effects assessment, thus implementing a life-cycle oriented approach in the assessment of the toxicity of CdTe QDs.

Effects of toner-handling work on respiratory function, chest X-ray findings, and biomarkers of inflammation, allergy, and oxidative stress: a 10-year prospective Japanese cohort study

Background

Exposure to toner, a substance used in photocopiers and printers, has been associated with siderosilicosis and other adverse effects. However, these findings are limited, and there is insufficient evidence on the long-term effects of toner exposure. Using longitudinal analysis, this study aimed to examine the effects of work involving toner exposure on the respiratory system over time.

Methods

We conducted a prospective cohort study in a Japanese toner and copier manufacturing enterprise between 2003 and 2013. The cohort included a total of 1468 workers, which comprised 887 toner-handling workers and 581 non-toner-handling workers. We subdivided the toner-handling workers into two groups according to the toner exposure concentration, based on the baseline survey in 2003. We compared the chest X-ray results, respiratory function indicators, and serum and urinary biomarkers of inflammation, allergy, and oxidative stress among the three groups: high-concentration toner exposure group, low-concentration toner exposure group, and non-toner-handling group. To consider the effects of individual differences on the longitudinal data, we used a linear mixed model.

Results

Similar chest X-ray results, the biomarkers, and most of the respiratory function indicators were found in the non-toner-handling and toner-handling groups. There were no significant yearly changes in the percentage of vital capacity (%VC) in the high-concentration toner exposure group, while there was a significant yearly increase in %VC in the low-concentration toner exposure group and non-toner-handling group. The yearly change in each group was as follows: high-concentration toner exposure group, − 0.11% (95% confidence interval [CI], − 0.29 to 0.08; P = 0.250); low-concentration toner exposure group, 0.13% (95% CI, 0.09–0.17; P < 0.001); and non-toner-handling group, 0.15% (95% CI, 0.01–0.20; P < 0.001).

Conclusions

In our 10-year prospective study, toner-handling work was not associated with the deterioration of respiratory function and an increase in biomarker values for inflammation, allergy, and oxidative stress. This finding suggests that toner-handling work is irrelevant to the onset of respiratory disease and has minimal adverse effects on the respiratory system under a well-managed work environment.

Supplementary Information

Supplementary information accompanies this paper at10.1186/s12890-020-01320-6.

A Cohort Study on Respiratory Symptoms and Diseases Caused by Toner-Handling Work: Longitudinal Analyses from 2003 to 2013

The purpose of this study was to examine the effects of toner-handling work on respiratory symptoms and diseases. We conducted a prospective cohort study of 1468 workers between 2003 and 2013. The cohort included 887 toner-handling workers and 581 non-toner-handling workers, employed in one toner and copier manufacturing enterprise. Toner-handling workers were subdivided into two groups based on the 8-h time-weighted average toner exposure concentration for each work category in the baseline survey. We compared the incidence of respiratory disease and longitudinal changes in the prevalence of subjective respiratory symptoms among three groups, as follows: High-concentration toner exposure group, the low-concentration toner exposure group, and a control group. The incidence of respiratory disease and changes in the prevalence of subjective respiratory symptoms were not significantly different between the non-toner-handling group and the toner-handling group. In contrast, the odds ratio for yearly changes in the prevalence of wheezing without asthmatic response was significantly lower in the high-concentration toner exposure group than in the control group. At the study site, dust scattering was well controlled and workers used respiratory protection appropriately. These findings suggest that toner-handling work had little adverse effect on respiratory function in a work environment with sufficiently controlled ventilation.

Environmental triggers for chronic cough

Cough is a physiological defense reflex for protecting the airways from aspiration and irritation. Thus, roles of environmental triggers are postulated in the pathogenesis of chronic cough. There are several lines of epidemiological evidence demonstrating the relationships between environmental irritant and pollutant exposure and chronic cough. However, positive findings from cross-sectional studies just reflect the protective nature of cough but may not properly address the true impact of environmental triggers. If harmful inhalation is repeated, cough may be seen as chronic but indeed is protective in nature. Therefore, long-term residual outcomes would be the key for understanding the effects of environmental triggers on chronic cough. The present review aims to summarize the associations between chronic cough and environmental pollutants or irritant exposure, with a focus on the long-term residual effects of (1) chronic persistent exposure and (2) acute high-intensity exposure on chronic cough, and also to examine (3) whether childhood irritant/pollutant exposure may increase the risk of chronic cough in adulthood.