Microplastics in indoor dust collected from medical waste disposal units: Occurrence and exposure assessment

Microplastics (MPs) are one of the predominant environmental pollutants found in various environments due to the widespread use of plastic products. However, no MPs have been reported in medical waste disposal units. The current research was carried out to scrutinize the frequency and characteristics of MPs and the amount of human exposure to MPs in the dust settled in various medical waste disposal units of Yazd hospitals in Iran. Eighteen dust samples from various medical waste disposal units (including temporary storage rooms, disposal rooms, and neutralized waste rooms) of Yazd hospitals were collected and analyzed. The average number of MPs in the indoor dust of various medical waste disposal units was 64.6 particles/mg. Within the temporary medical waste storage unit, the dust contained the highest observed number of MPs, with an average of 145 items/mg. The most frequently observed characteristics of MPs were blue color (47%), fiber shape (86%), and polyethylene polymer (36%). The predominant size of MP particles identified is between 10 and 1000 µm (74%). Findings have demonstrated that all medical waste disposal units contain significant levels of MPs, even in the sterilized waste disposal unit by autoclaving. Teenagers are most exposed to MPs in these units, which may result in significant exposure risk, specifically for teenagers and adults. This issue may pose significant risks for the units' personnel and those traveling to the hospitals. Therefore, specific strategies and effective policies must be used to reduce the exposure of people working in medical waste management facilities to MPs.