Assessment of the concentrations of U and Th in PM2.5 from Mexico City and their potential human health risk

Abstract

This is one of the first studies in small particulate matter (PM2.5) by inductively coupled plasma sector field mass spectrometry to measure the activity concentrations of isotopic uranium (234, 235 and 238U) and thorium (232Th) in these fine particulates, to know their origin and their impact on human health in Mexico City. A different isotopic composition from the natural uranium composition was found. The 235U/238U atom ratio values are considered as low enrichment uranium, around 2% of 235U enrichment. Both 235U/238U and 234U/238U ratios suggested anthropological rather natural source is impacting the composition of uranium in PM2.5.