## 4 Conclusions  
* The Three Kids Mine tailings may present human health risks from their transport offsite on airborne particles. The XRF was used to successfully follow the concentrations these and other tailings elements to background levels along eight transects leading away from the dried tailings ponds.
* The most distant transport of Mn, Cu, Zn, As, Sr, Mo, and Pb is to the N.E. from the tailings ponds on transects 1 and 2. A wind rose diagram from the closest air quality monitoring station data, situated to the SW of TKM, shows that the predominant winds are from the SW, suggesting that the predominant dispersal of mine tailings will be to the NE, in agreement with results shown in transport diagrams for the tailings chemical elements. Future home sites are on a NE transect between 0.4 km and 2.3 km downwind from the tailings ponds, in an area highly impacted by tailings which exceed the USEPA RSLs.  
Figure 4: Photo showing encroachment of housing projects in the vicinity of the TKM. The light colored area to the east and just north of Lake Mead Parkway has new home sites. Google Earth.  
Figure 3: Photo showing encroachment of housing projects in the vicinity of the TKM. The light colored area to the east and just north of Lake Mead Parkway has new home sites. Google Earth.  
* Along all transects, except Transect7, the U.S. EPA Regional Screening Levels for As, Pb, and Mn are exceeded at 0.8 km. The RSLs are also exceeded for As, Pb and Mn on the two NE transects at 1.6 km.
* From visual inspection of the topography, water runoff from the tailings ponds is funneled downhill through a culvert under Lake Mead Parkway, through the Lake Las Vegas Resort, to the Las Vegas Wash. Thus, the results reported in the transport diagrams in Figure 3, are due to the mobilization of particulates from the mine by wind, not water transport.
* This research suggests that, because of the high concentrations of Mn, As, Sr, and Pb in the tailings, they may present a health hazard in relocating the tailings material back to the pits from which it came. Therefore, stringent precautions must be taken, if and when the proposed remediation of the TKM site goes forward, to prevent the tailings from being transported offsite as dust to the natural environment and to the surrounding occupied houses.  
**Table A1.**_Cont._  
\begin{tabular}{c c c c c c c c c} \hline \hline
**Distance** & \multicolumn{6}{c}{**Concentration of Zinc (mg/kg)**} \\ \cline{2-10}  & **Transect 1** & **Transect 2** & **Transect 3** & **Transect 4** & **Transect 5** & **Transect 6** & **Transect 7** & **Transect 8** \\ \hline Tailings & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 & 2050 \(\pm\) 50 \\
0.8 km & 920 \(\pm\) 30 & 2710 \(\pm\) 40 & 190 \(\pm\) 10 & 860 \(\pm\) 30 & 640 \(\pm\) 30 & 260 \(\pm\) 20 & 76 \(\pm\) 11 & 340 \(\pm\) 20 \\
1.6 km & 260 \(\pm\) 20 & 480 \(\pm\) 30 & NA & 78 \(\pm\) 11 & 63 \(\pm\) 11 & 78 \(\pm\) 12 & 61 \(\pm\) 11 & 84 \(\pm\) 11 \\
3.2 km & 87 \(\pm\) 12 & 160 \(\pm\) 10 & 70 \(\pm\) 10 & 78 \(\pm\) 11 & 85 \(\pm\) 12 & 68 \(\pm\) 11 & 60 \(\pm\) 10 & 60 \(\pm\) 10 \\
4.8 km & 61 \(\pm\) 12 & 60 \(\pm\) 10 & 45 \(\pm\) 10 & 63 \(\pm\) 11 & 82 \(\pm\) 11 & 56 \(\pm\) 11 & NA & NA \\
6.4 km & 91 \(\pm\) 11 & 81 \(\pm\) 12 & 42 \(\pm\) 11 & 59 \(\pm\) 11 & 81 \(\pm\) 12 & 74 \(\pm\) 12 & 91 \(\pm\) 12 & 58 \(\pm\) 11 \\
8.0 km & 63 \(\pm\) 11 & NA & 53 \(\pm\) 11 & NA & 86 \(\pm\) 12 & 83 \(\pm\) 11 & 53 \(\pm\) 11 & 44 \(\pm\) 12 \\ \hline
**Distance** & \multicolumn{6}{c}{**Concentration of Arsenic (mg/kg)**} \\ \cline{2-10}  & **Transect 1** & **Transect 2** & **Transect 3** & **Transect 4** & **Transect 5** & **Transect 6** & **Transect 7** & **Transect 8** \\ \hline Tailings & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 & 3690 \(\pm\) 80 \\
0.8 km & 2890 \(\pm\) 60 & 820 \(\pm\) 40 & 120 \(\pm\) 10 &