Anthropogenic Source of Gold in Moscow Urban Dust

Estimation of the concentration and distribution of gold in the dust, soil, bottom sediments, and technological dumps is an essential task of analytical chemistry, which must be solved not only in assessing recoverable resources. The determination of gold also has an environmental aspect, because this metal was recognized an allergen. In the present work, over 80 samples of Moscow Urban dust were studied using complementary analytical methods: inductively coupled plasma–mass spectrometry and scanning electron microscopy with energy dispersive X-ray spectroscopy. In some samples, the concentration of gold exceeded 1 µg/g and even reached 30–35 µg/g. Gold is present in the dust as microparticles no larger than 2–3 µm in size. The high concentration of gold in particles (about 99%) virtually excludes jewelry as its source. The study of the sampling map suggests that, with a high probability, the main anthropogenic source of gold in Moscow Urban dust is the gradual wear of church domes covered with high-grade gold leaf.