Metal and dust exposure in workers from the metal recycling industry in Sweden: cross-sectional GreenMetalWaste study

The green transition relies on metals, requiring increased metal recovery from waste. However, exposure risks among metal recycling workers are poorly understood. We conducted a cross-sectional study to assess dust and metal exposure among 139 recycling workers from 13 Swedish metal recycling companies and 90 controls. We documented work practices through observations and questionnaires and assessed dust and metal exposures using a combination of individual air sampling (inhalable (ID) and respirable dust) and biomonitoring (blood and pre-/post-shift urine). ICP-MS was used to measure 39 metals in air, 47 in blood, and 42 in urine. Thirty-two % of the workers were involved in the recycling of e-waste. At most workplaces, dust control was insufficient, respiratory protective equipment was rarely or incorrectly used, and hygienic routines were inadequate. This was reflected in 6.2 times higher ID levels in recycling workers; 14 % exceeded the 5 mg/m³ exposure limit for ID, and some also exceeded limits for Pb, Cu, As, Cd, and Sb. Workers had elevated blood and/or urine levels of Pb, Hg, Al, Sb, Fe and Mn with known human toxicity, and of Y, Lu, In, Ga, W, and Te with limited or unknown toxicity. Furthermore, observed were also co-exposure patterns for those metals. Inhalation was the likely primary exposure route for Pb, Sb, Y, In, and Te. In conclusion, Swedish recycling workers were exposed to elevated levels of dust and metals, highlighting the need for ongoing monitoring of both known and emerging metals.