## 1 Introduction  
The tailings ponds at the Three Kids Mine (TKM) cover an area of approximately 0.4 km\({}^{2}\) and their dry surface soil contains, according to the results reported herein, high concentrations of Mn (153,000 mg/kg), Sr (18,700 mg/kg), Pb (15,300 mg/kg), As (3690 mg/kg), Zn (2050 mg/kg), and are enriched in Cu (260 mg/kg). Since this mine is located in an arid climate with frequent high winds, and dust devils, the transport of tailings particulates offsite is highly probable. Four hypotheses were formulated to be tested during the study of this abandoned mine: (1) the most distant transport of particles containing Mn, Sr, Pb, As, Zn, and Cu from the surface of the dried tailings ponds will be found to be in directions predicted from wind rose diagrams from the closest air quality monitoring station; (2) toxic material has been carried offsite; (3) the concentrations of Mn, Pb, and As offsite will exceed the U.S. Environmental Protection Agency's Regional Screening Levels (EPA RSLs); and (4) the sensitivity of the portable X-ray fluorescence spectrometer will be sufficient to follow the concentrations of several toxic elements from the center of the tailings ponds to background levels offsite. Of the elements found in high concentrations at the TKM, the toxic effects of Pb and As in the environment are well known [1]. A report on the chronic exposure to airborne manganese (Mn) in the vicinity of an active Mn mine in Mexico, suggests that \"airborne Mn-environmental exposure is inversely associated with intellectual function in young school-age children\" [2]. Another study of children living near active Mn mining operations in the Ukraine concludes that \"chronic Mn exposure is a health hazard\" [3]. Additionally, a study of mineworkers in South Africa concludes that there were \"adverse effects on the central nervous system\" from breathing Mn-containing dust [4]. Manganism, or manganese poisoning, results in impaired motor functions, psychiatric disturbances, and symptoms resembling Parkinson's disease [5]. Chronic inhalation of Mn in excess of 5 \(\mathrm{\SIUnitSymbolMicro m}\)\({}^{3}\), may result in manganism [6]. In a report on strontium in soil, the authors conclude that there was a significant increase in the clinical signs of rickets when the concentration of Sr in the soil was greater than 350 mg/kg [7]. The EPA has established RSLs for Mn, Sr, Pb, As, Zn, and Cu [8]. The RSLs \"are based on human risk assessment, but do not address ecological risk\" [8]. The RSLs are not cleanup levels, but suggest that more information is needed on: \"the site, land use, impacted media, and the likely pathway for human exposure\" [8]. The TKM is an abandoned manganese mine, which is located in metropolitan Las Vegas, NV, USA (population 2.0 million [9]), on the eastern border of the City of Henderson (population 270,000) [9]. The mine is located about 8 km NE of downtown Henderson, 20 km SE of downtown Las Vegas, and 18 km east of McCarran International Airport, see Figure 1. It was discovered in 1917 and operated intermittently when the need for manganese was stimulated by WWI, WWII, and the cold war [10; 11; 12; 13; 14]. When in operation, the TKM was an open-pit mine and processing operation. The mine accounted for a third of the Mn production in the U.S. from 1955 to 1961 [15]. During the years it was active, the TKM contributed significantly to the development of the cities of Henderson and Las Vegas, and the state of Nevada. At the high temperatures reached during the calcination process, Pb and Zn were released to the atmosphere [10]. It is one of thousands of abandoned mines in the state of Nevada [16]. The mine site has: (1) large-unprotected tailings ponds (containing approximately 2 to 3 million cubic meters of material) with high concentrations of lead, arsenic, manganese, strontium, and petroleum hydrocarbons; (2) large quantities of waste rock; (3) four open pits; and (4) the remains of seven circular ore processing thickeners [10, 13, 14, 17].