Occupational exposure to microplastics and heavy metals: a workstation-based study across small-scale, medium-scale,...

In India, a large number of workers in plastic manufacturing industries may be exposed to airborne microplastics (MPs). However, data on occupational exposure levels remain limited. This study aimed to assess occupational exposure to MPs in small, medium, and large-scale plastic manufacturing industries in Nagpur, India. Nagpur, a major industrial hub, provided a representative setting for evaluating such exposures across diverse industry scales. Airborne respirable samples (n = 30; 10 per industry type) were collected during 8-h work shifts using a Sidekick-51MTX dust sampler. Respirable dust collected on PVC filter papers was analyzed for MPs using stereomicroscopy for visualization, fluorescence microscopy for quantification, and ATR-FTIR spectroscopy for polymer characterization. The highest airborne microplastic concentration was observed in medium-scale industries (43 ± 8 particles/m³), followed by small-scale (38 ± 10 particles/m³) and large-scale industries (30 ± 10 particles/m³) for time-weighted average (TWA₈) in shifts. The corresponding filter-based counts were 12 ± 5.8, 13.7 ± 6.5, and 9.5 ± 4.9, respectively. MPs exhibited fibres and fragments, mostly < 1 mm, with fiber lengths ranging from 21 to 1353 µm. Trace elements (Pb, Cd, As, Hg, Ni) were analyzed using hot block digestion (NIOSH 7303 method) and were within permissible limits under the Factories Act, 1948. This study shows the presence and characteristics of airborne microplastics across plastic manufacturing industries, along with associated occupational exposure to trace elements, and provides baseline information for future studies in Indian settings.