광미내 Zn의 탈착 특성과 지렁이에 대한 생이용성 (Desorption Characteristics and Bioavailability of Zn to Earthworm in Mine Tailings)

서지정보

· 발행기관 : 한국지하수토양환경학회
· 수록지 정보 : 지하수토양환경 / 16권 / 4호 / 38 ~ 52페이지
· 저자명 : 오상화, 신원식

초록

Sorption and sequential desorption experiments were conducted for Zn using a natural soil (NS) in background status by aging (1, 30 and 100 days). The sorption isotherm showed that Zn had high sorption capacity but low sorption affinity in NS. Sequential desorption was biphasic with appreciable amount of sorbed Zn residing in the desorption-resistant fraction after several desorption steps. The biphasic desorption behavior of Zn was characterized by a biphasic desorption model that includes a linear term to represent labile or easily-desorbing fraction and a Langmuirian-type term to represent desorption-resistant fraction. The biphasic desorption model indicated that the size of the maximum capacity of desorption-resistant fraction (q^irr_max ) increased with aging in NS. Desorption kinetics and desorption-resistance of Zn in the soils collected from mine tailings (MA, MB and MC collected from surface, subsurface soils and mine waste,respectively) were investigated and compared to the bioavailability to earthworm (Eisenia fetida). Desorption kinetic data of Zn were fitted to several desorption kinetic models. The ratio (q_e, d / q_0) of remaining Zn at desorption equilibrium (q_e, d )to initial sorbed concentration (q_0) was in the range of 0.53~0.90 in the mine tailings which was higher than that in NS,except MA. The sequential desorption from the mine tailings with 0.01M NaNO_3 and 0.01M CaCl_2 showed that appreciable amounts of Zn are resistant to desorption due to aging or sequestration. The SM&T (Standard Measurements and Testing Programme of European Union) analysis showed that the sum of oxidizable (Step III) and residual (Step IV)fractions of Zn was linearly related with its desorption-resistance (q^irr_max ) determined by the sequential desorption with 0.01M NaNO_3 (R^2= 0.9998) and 0.01M CaCl_2 (R^2= 0.8580). The earthworm uptake of Zn and the desorbed amount of Zn (q_desorbed = q_0 −q_e,d) in MB soil were also linearly related (R^2 = 0.899). Our results implicate that the ecological risk assessment of heavy metals would be possible considering the relation between desorption behaviors and bioavailability to earthworm.

영어초록

Sorption and sequential desorption experiments were conducted for Zn using a natural soil (NS) in background status by aging (1, 30 and 100 days). The sorption isotherm showed that Zn had high sorption capacity but low sorption affinity in NS. Sequential desorption was biphasic with appreciable amount of sorbed Zn residing in the desorption-resistant fraction after several desorption steps. The biphasic desorption behavior of Zn was characterized by a biphasic desorption model that includes a linear term to represent labile or easily-desorbing fraction and a Langmuirian-type term to represent desorption-resistant fraction. The biphasic desorption model indicated that the size of the maximum capacity of desorption-resistant fraction (q^irr_max ) increased with aging in NS. Desorption kinetics and desorption-resistance of Zn in the soils collected from mine tailings (MA, MB and MC collected from surface, subsurface soils and mine waste,respectively) were investigated and compared to the bioavailability to earthworm (Eisenia fetida). Desorption kinetic data of Zn were fitted to several desorption kinetic models. The ratio (q_e, d / q_0) of remaining Zn at desorption equilibrium (q_e, d )to initial sorbed concentration (q_0) was in the range of 0.53~0.90 in the mine tailings which was higher than that in NS,except MA. The sequential desorption from the mine tailings with 0.01M NaNO_3 and 0.01M CaCl_2 showed that appreciable amounts of Zn are resistant to desorption due to aging or sequestration. The SM&T (Standard Measurements and Testing Programme of European Union) analysis showed that the sum of oxidizable (Step III) and residual (Step IV)fractions of Zn was linearly related with its desorption-resistance (q^irr_max ) determined by the sequential desorption with 0.01M NaNO_3 (R^2= 0.9998) and 0.01M CaCl_2 (R^2= 0.8580). The earthworm uptake of Zn and the desorbed amount of Zn (q_desorbed = q_0 −q_e,d) in MB soil were also linearly related (R^2 = 0.899). Our results implicate that the ecological risk assessment of heavy metals would be possible considering the relation between desorption behaviors and bioavailability to earthworm.

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