Potential Toxic Effects from Micro- and Nanoplastics — Insights from Occupational Studies
Abstract No:
1131
Abstract Type:
Professional Poster
Authors:
G Zarus1
Institutions:
1ATSDR/CDC, Atlanta, GA
Presenter:
Gregory Zarus
ATSDR/CDC
ATSDR/CDC
Description:
Human exposure to environmental microplastics (MP) and the potential for harmful health effects have become a widely covered topic in the scientific literature. Although the range size of MP (<5mm) may include particles of respirable size, most of the reports on human health risks are extrapolated from environmental media to which most people have very little contact. Further, reports indicate that MP includes materials of various chemical compositions, shapes, colors, sizes and densities, which add complexity to the challenges of developing sound measurement methods. Important gaps in sampling and characterization of MP, and activity patterns need to be addressed, to enhance our understanding of the potential adverse health effects on human health. We focused on the flocking (surface texture), synthetic textile, and PVC industries to highlight similarities and differences of their potential health effects and compare them with similar exposures to non-MP and NP materials. We also include findings of germane animal studies, which assessed the effects on target organs when exposing them to MP generated in the workplace.
Situation / Problem:
Microplastics are ubiquitous in the environment; thus, we need robust data to better characterize exposures and potential health risks. Recently, the World Health Organization highlighted the need for comprehensive toxicological assessments and enhanced understanding of multiple exposure pathways to determine the potential human health risks of MPs. Findings from occupational exposure studies indicate both common and unique health effects in workers that appear associated to MP and nanoplastics (NP) exposures via inhalation and ingestion. Most occupational studies focused on airborne MP, which vary in size, chemical composition, and concentration depending on the industry type and sampling location within the industrial plants. Dyspnea caused by interstitial lung inflammation has been identified as a common health risk to workers. Precancerous and cancerous effects are less certain, but some potential associations of occupational exposures to specific plastic types have been reported. Most studies in the flocking and synthetic textile industries indicate respiratory effects associated with inhalation of MP.
Methods:
An online literature review of publications that focused on the health risks associated to MP exposures was conducted as follows: 1) a general online search for publications that mentioned human health implications due to exposures to MP; 2) cataloged MP associated case reports and studies, and epidemiologic studies of workers exposures, accidental exposures, and surgical exposures; 3) references targeting worker-related exposures to anthropometric MP; and 4) separated studies into categories of health effects observed due to potential exposures to a specific MP. Based on the results of this stepwise review, we determined that the majority of the studies focused on the flocking, synthetic textile, and PVC industries. Next, we reviewed animal studies that used the same types of MP and NP produced in some workplace settings. Then, we summarized the selected studies to describe the industry, particle size (if available), study sample size and workers data, and adverse health effects. Finally, we examined these studies to characterize any differences in adverse health effects by chemical type, particle size and concentration, industry, and duration of exposure.
Results / Conclusions:
Based on our literature search criteria, we identified thirty-six publications. Authors reported findings of restricted airways, pulmonary inflammation, reduced lung function, and abnormal lung X-rays. While measurements are lacking in most of these MP and NP studies, significant effects have been reported with respirable particulate levels as low as 0.53 mg/m3 in the flock industry. Findings from animal studies exposed to similar MP and NP produced in the workplace showed immediate inflammation as a result of exposures to flock dust and pointed to a dose response relationship. Reduced lung function was measured as reduction of forced expiratory volume (46-81%) and forced vital capacity (39-56%) in these studies. Loss of lung function was associated with years worked and with dustier environments, but lung function tests differed in many of the studies, and particulate measurements only provided as snapshots in the workers' histories.
Findings of occupational studies in the flock industry revealed that most adverse health effects in workers were associated with respiratory health outcomes. Polyester used as flock appeared to have a greater effect on the lung than nylon flock. Colorectal cancers were observed in workers who worked near dyed synthetics fibers. Adverse gastrointestinal effects among workers of the paper industry appear to be limited to those involved with the dye process. Protein markers indicated high strength synthetic fibers were nearly as toxic as crocidolite and chrysotile asbestos to tracheal epithelia. Lung and liver cancers were identified as health outcomes among PVC workers. .
This study adds to the literature by identifying MP health effects from occupational and animal studies. Results from these occupational studies reveal toxicological endpoints that should be targeted in future studies. While the unique health effects observed from workplace exposure to MP is apparent, the lack of standard measurement methods prevents us from accurately estimating dose response and risk. In addition, estimating and understanding non workplace risk with a certain level of certainty becomes difficult. Therefore, comprehensive human health risk studies will require that standardized MP measurement and sampling protocols be developed.
Findings of occupational studies in the flock industry revealed that most adverse health effects in workers were associated with respiratory health outcomes. Polyester used as flock appeared to have a greater effect on the lung than nylon flock. Colorectal cancers were observed in workers who worked near dyed synthetics fibers. Adverse gastrointestinal effects among workers of the paper industry appear to be limited to those involved with the dye process. Protein markers indicated high strength synthetic fibers were nearly as toxic as crocidolite and chrysotile asbestos to tracheal epithelia. Lung and liver cancers were identified as health outcomes among PVC workers. .
This study adds to the literature by identifying MP health effects from occupational and animal studies. Results from these occupational studies reveal toxicological endpoints that should be targeted in future studies. While the unique health effects observed from workplace exposure to MP is apparent, the lack of standard measurement methods prevents us from accurately estimating dose response and risk. In addition, estimating and understanding non workplace risk with a certain level of certainty becomes difficult. Therefore, comprehensive human health risk studies will require that standardized MP measurement and sampling protocols be developed.
Primary Topic:
Aerosols
Secondary Topics:
Nanotechnology
Toxicology
Co-Authors
Please add your co-authors below. Co-authors are listed for professional courtesy and will not be communicated with regarding the decision notification or any on-site logistics, if accepted. Only the primary presenter listed is expected to attend and present the content on-site.
Candis Hunter, NCEH
Custodio Muianga, ATSDR
Acknowledgements and References
List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).
Brown D, et al. (2001) Size-dependent proinflammatory effects of ultrafine polystyrene particles
Card C, et al. (2014) Emerging roles of lymphatic endothelium in regulating adaptive immunity
Checkoway, H, et al. (2010) Lung cancer and occupational exposures other than cotton dust and endotoxin among women textile workers in Shanghai
De Roos, et al. (2005) Colorectal Cancer Incidence among Female Textile Workers in Shanghai
Dris, R, et al. (2017) A first overview of textile fibers including MP in indoor and outdoor environments
Gasperi, J., et al. (2015) First overview of MP in indoor and outdoor air.
Gardiner K, et al. (1992) Occupational exposure to carbon black in its manufacture.
Gardiner K, et al. (1996) Ibid: data from 1987-92
Gardiner K, et al. (2001) Respiratory health effects from exposure to carbon black
Ghio, A, et al. (2006) Pulmonary Fibrosis and Ferruginous Bodies Associated with Exposure
to Synthetic Fibers
Gripenback, S, et al. (2005) Accumulation of eosinophils and T-lymphocytes in the lungs after exposure to pinewood dust
Järvholm B (2000) Natural organic fibers -health effects
Jones R, et al., (1988) A mortality study of VC monomer workers employed in the UK in 1940–74
Kern D et al. (2000) Flock worker’s lung. Broadening the spectrum of clinicopathology, narrowing the spectrum of suspected etiologies
Kern D, et al. (1998) Flock worker’s lung: Chronic interstitial lung disease in the nylon flock industry
Kreiss, K. (2013) Oc. Lung Disease From Case Reports to Prevention.
Kononenko,V, et al. NP interaction with the immune system
Lithner, D, et al. (2011) Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition
Mastrangelo G, et al. (1979) PVC pneumoconiosis
Paudyal, P, et al. (2011) Exposure to Dust and Endotoxin in Textile Processing Workers.
Reddy ST, et al. (2006) In vivo targeting of dendritic cells in lymph nodes with poly(propylenesulfide) NP
Reddy ST, et al. (2007) Exploiting lymphatic transport and complement activation in NP vaccines
Schneider, T, et al. (1996) Ubiquitous fiber exposure in selected sampling sites in Europe
Tang L, et al. Synthesis and biological response of size-specific, monodisperse drug-silica nanoconjugates
Thomas SN, et al. (2014) Targeting the tumor-draining lymph node with adjuvanted NP reshapes the anti-tumor immune response
Urban, RM et al. Dissemination of wear particles to the liver, spleen, and abdominal lymph nodes
Vianello, A, et al. (2019) Simulating human exposure to indoor airborne MP using a Breathing Thermal Manikin
Volkheimer, G. Hematogenous dissemination of ingested PVC particles
Walker, PS, Bullough, PG (1973) The effects of friction and wear in artificial joints
Warheit DB, et al. (2001) Potential pulmonary effects of man-made organic fiber dusts