우리나라 토양의 크롬 분포특성에 관한 고찰

초록

Chromium as a constituent of rocks occurs naturally in the environment in varying concentrations. However, the human activity has changed the geochemical cycle of chromium in the environment and has caused the chromium accumulation in soils. Korean soils revealed a wide range of chromium contents depending on parent material and land use. The total chromium contents of volcanic ash soils in Jeju, which were determined using HNO₃ + HClO₄ + HF, ranged from 434 to 1,164 mg kg-¹. The ‘ecological’ total chromium contents extracted using conc. HCl + conc. HNO₃ (aqua regia) in the same soils varied in a lower range of 50-189 mg kg-1 (averaged percentage of aqua regia contents in HNO3 + HClO₄ + HF contents: 14.9%). Serpentine soils in Andong showed a ‘ecological’ total chromium content of 309 mg kg-¹ and against it granitic soils in Andong only 20 mg kg-1. In uncontaminated forest soils of Korea, the ‘ecological’ total chromium contents varied from 4.89 to 106 mg kg-1 and the soluble chromium contents determined using 0.1 M HCl ranged from 0.01 to 0.64 mg kg-¹ (averaged percentage of 0.1 M HCl contents in aqua regia contents: 0.4%). Arable lands contained more soluble chromium than reported in forest soils (averaged soluble chromium: 0.36 and 0.09 mg kg-¹, respectively). In particular, the soluble chromium contents in greenhouse, orchard and upland soils were higher than in contaminated soils near mine and industrial site (maximum contents:greenhouse 15.3 mg kg-¹; upland 12.1 mg kg-¹; orchard 8.29 mg kg-¹; mine site 4.76 mg kg-¹; industrial site 2.80 mg kg-¹). On the basis of these results a accumulation of chromium in some specific arable lands can be assumed,probably by long-continued applications of fertilizers or soil amendments containing chromium. In Korean Enforcement Decree of the Soil Environment Conservation Act soil standards for total chromium do not exist yet.

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