Evaluating Soil Respiration as Indicator of Heavy Metal Pollution in Agricultural Field

Agricultural field near at the abandoned metal mine and industrial area has a high possibility to be polluted by heavy metals. However, concern about chemical properties including heavy metal concentration has been increased and biological properties such as soil respiration has been minimal in heavy metal polluted field. Therefore, main objective of this research was to evaluate soil respiration as an indicator of heavy metal pollution in agricultural field. Total of 60 sampling sites including each 30 sites of abandoned metal mine and industrial area were selected and heavy metal concentration, soil respiration, and chemical properties were measured. Results showed that heavy metal concentration in metal mine area was ranged Cu: $6.21~85.23mg\;kg^{-1}$, Pb: $23.84{\sim}1,044.72mg\;kg^{-1}$, As: $1.88{\sim}691.44mg\;kg^{-1}$, Zn: $18.72{\sim}527.55mg\;kg^{-1}$, Cd: $0.58{\sim}4.27mg\;kg^{-1}$, and Cu: $0.29{\sim}30.62mg\;kg^{-1}$, Pb: $4.41{\sim}19.77mg\;kg^{-1}$, As: $2.23{\sim}11.76mg\;kg^{-1}$, Zn $39.98{\sim}109.59mg\;kg^{-1}$, Cd $0.29{\sim}0.57mg\;kg^{-1}$ for industrial area respectively. While no sampling site was exceed the threshold value of each heavy metals in industrial field, metal mine area was highly polluted with Pb, As, Zn, and Cd. Soil respiration in the metal mine and industrial area was ranged $12.05{\sim}299.80mg\;O_2\;kg^{-1}$ and $27.68{\sim}330.94mg\;O_2\;kg^{-1}$, respectively. Correlation analysis between heavy metal concentration in soil and soil respiration showed that negative correlation was observed in metal mine area while no correlation was observed in industrial area. This result might indicate that as heavy metal concentration was increased, microbial activity in soil was decreased resulting decrease of soil respiration rate. Overall, soil respiration can be used as indicator of heavy metal pollution in soil and more biological properties need to be evaluated to better understand heavy metal pollution in soil.