## 3 Results and Discussion  
### Geochemical Properties of Soil  
The transport and distribution of heavy metals in soil in the shooting area results in serious heavy metal contamination [24]. As mentioned above, Pb is considered to be the primary contaminant, accounting for the largest proportion of heavy metal contamination [12; 14; 15; 16; 17; 18]. Lead is insoluble [28] and insignificantly affected by secondary effects [29]. The Pb mobility and solubility depend on the environmental conditions including the physicochemical properties of the soil, shooting range type, purpose of use, and vegetation (root exudates) [2; 5; 30]. In general, a large proportion of Pb in the soil from shooting ranges and their vicinity is considered to originate from Pb shots [6]. The soil physicochemical properties and distribution of heavy metals in soils from Korea military shooting ranges have been analyzed in several previous studies. [PERSON] and [PERSON] [31] evaluated the heavy metal contamination of soils in Maehyang-ri in the Gyeonggi-do shooting range. The shooting range was operated for 50 years until 2005. The Maehyang-ri area has been contaminated with heavy metals from explosives (trinitrotoluene, TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, HDX) associated with bombs, practice bullets, ammunition, and unexploded ammunition [31]. [PERSON] and [PERSON] [31] compared the heavy metal concentration in Maehyang-ri with that in other shooting ranges in South Korea and identified the major heavy metal contaminants in the Maehyang-ri shooting range. Based on their research, the Cu concentration in the study area is 23 times higher than that of soils in South Korea and the Pb concentration is 1.2 times higher than the soil pollution standard [31]. [PERSON] and [PERSON] [22] investigated the heavy metal concentrations and distribution in soils, plants, and water samples in the same shooting area. They reported that the heavy metal concentration is the highest near the targets and that the proportion of Pb is higher than that of other heavy metals. Based on their results, both surface and deeper soils are enriched in heavy metals because of adsorption; however, they did not evaluate the heavy metal leaching from soil by surface water [22]. Several researchers have suggested that the Pb concentrations in the surface water and plants in the shooting range are significantly affected by the Pb concentration of the soil [17; 30; 32]. The geochemical properties of the soils from the shooting range are presented in Table 1. The Pb concentration in the vertical soil profiles of the shooting range is heterogeneous. Figure 2 shows that the Pb concentration is high regardless of the soil depth, which is due to the discharge of bullets at all depths and diffusion/transport of Pb [11]. In some firing ranges, arsenic (As) was not detected due to its low concentration. The Pb concentrations of the surface soils from the third and sixth shooting lanes were 100 to 1000 times higher than that of the background soil, respectively. Heavy metals are generally enriched in the surface soil compared with deeper soil, indicating the preferential contamination of the surface soil and mobilization through the soil profile (Figure 2) [24]. However, in the drain ditch, the heavy metal contents were highest in the deeper soil. It can be assumed that the leaching of heavy metals from the surface soil by water at the drain ditch had occurred [24]. It seems that the heavy metal accumulation processes due to several controlling factors had occurred during the 30-year operation period of the shooting range. The total Pb concentration of soils from the shooting range determined in this study is as high as values reported in previous studies and higher than the Korean pollution standard [3]. In Korea, the standard concentration in shooting ranges is 700 ppm for Pb;2000 ppm for Cu; 2000 ppm for Zn; 500 ppm for Ni; 200 ppm for As; and 60 ppm for Cd [22].