Trace elements in laundry dryer lint: A proxy for household contamination and discharges to waste water

Seventy samples of laundry dryer lint from 19 households have been analysed for trace elements (As, Br, Cu, Fe, Ni, Pb, Sb, Zn) by energy-dispersive portable X-ray fluorescence (XRF) spectrometry. Bromine, Fe and Zn were detected in more than sixty samples encompassing all households, with dry weight concentrations ranging from 5.5 to 213 μg g^-1, 76 to 3580 μg g^-1 and 24 to 3540 μg g^-1, respectively. Lead and Sb were detected in twenty and eight samples from ten and seven households, respectively, with concentrations ranging from about 8 to 110 μg g^-1 for Pb and 40 to 90 μg g^-1 for Sb. In contrast, As was only detected in six samples from the same household with concentrations ranging from about 10 to 250 μg g^-1. Analysis of 72 items of new or clean clothing and linen revealed the ubiquity of Sb in synthetic (largely polyester-based) articles and the presence of Br in a variety of natural and synthetic articles, suggesting that the dominant source of these elements in dryer lint is derived from clothing fibres themselves; specifically, Sb₂O₃ is employed as a catalyst in the manufacture of polyester and various brominated compounds appear to be used as disperse dyes. No detectable As or Pb in the clothing-linen samples indicates that their presence in dryer lint arises from contamination of laundry from extraneous sources (e.g. household dust and material accumulated from outdoor activities) and suggests that concentrations can be used as proxies for exposure or household contamination. Since dryer lint is representative of material shed during the washing of clothes and linen, its composition also serves as a proxy for contaminants entering the environment from this process. Of particular significance in this respect is the discharge of chemicals specific to textiles or associated with microfibers.