Heavy metal pollution in agricultural field near at the abandoned metal mines is a critical problem in Korea. General remediation technique is to apply chemical amendments and soil covering. However, evaluation of remediation efficiency only with reduction of bioavailable concentration in soil has limitation. The main objective of this research was to evaluate effect of chemical stabilization on plant and soil enzyme activity in heavy metal contaminated agricultural field. Column and pot experiment were conducted to evaluate efficiency of chemical amendments and effect on plant and soil enzyme activity. Result showed that soil pH was increased comparing to control at the order of steel slag(7.12) > lime stone (7.14) > AMD sludge (6.28) after experiment. Consequently, bioavailable fraction of heavy metals was decreased according to increase of soil pH. Contrary to the assumption that the antioxidant enzyme activity would be proportional to the level of the heavy metal concentration, only CAT activity shows positive correlation with the heavy metal concentration, while GR and APX activity has inverse correlation. In case of APX activity, AMD sludge applying 3% in the heavy metal contaminated soil showed the highest activity(0.0331 U mg-1 protein). For soil enzyme activity, the highest activity of β-glucosidase was observed when 5% of lime stone was applied. Meanwhile, phosphatase activity was high in following order of AMDS(4.01 nmol min-1 g-1(dry weight)) > SS(2.50nmol min-1 g-1(dry weight)) > LS(2.31nmol min-1 g-1(dry weight)). In cas of AMDS application, the activity was greater in 3% and 10% treatment(4.1 and 4.4 nmol min-1 g-1(dry weight)) than in 5%(3.1) treatment.
Overall, the result of chemical and biological assessments indicates that it is more appropriate to use AMD sludge (AMDS) than limestone (LS) or steel slag (SS) which lower the soil enzyme activity. Among others, phosphatase activity is appropriate to assess effect of chemical amendment on soil quality. Heavy metal pollution in agricultural field can have adverse effect not only on crops but also on human health. In order to properly evaluate soil sustainability after remediation in heavy metal polluted soil, chemical and biological assessment should be conducted.