Abstract
In this study, seeds of Festuca ovina var. coreana growing in waste coal landfills exposed to heavy metal contamination for a long time were collected, and growth characteristics and heavy metal accumulation capacity were evaluated through greenhouse cultivation experiments with germinated seedlings, and was conducted for the applicability of phytoremediation technology. Concentration gradients of arsenic-treated artificial soil were 25, 62.5, 125, and 250 mg/kg, respectively, lead concentrations were 200, 500, 1000, and 2000 mg/kg, and cadmium concentrations were 15, 30, 60, and 100 mg/kg, respectively In the arsenic, lead, and cadmium-treated experimental groups, the number of leaves of F. ovina var. coreana decreased in all compared to the control group except for the lead-treated groups (200, 500, and 1000 mg/kg). Length growth of the shoot part was increased in all of the arsenic treatment groups compared to the control group, but decreased in all of the root parts. In the 1000 and 2000 mg/kg lead treatment groups, lengths increased compared to the control group, but in the other treatments, they were shorter than the control group. In the case of the cadmium treatment group, all of the shoot parts were increased compared to the control group, and all of the root parts were decreased. In the case of arsenic treatment, the biomass was decreased at all parts and all concentrations compared to the control group. The 200, 500, and 1000 mg/kg lead treatments showed larger biomass than the control group in both shoot and root parts. In the cadmium treatment group, the biomass of both shoot and root parts decreased compared to the control group. As the concentration of heavy metal treatment increased, both the number of leaves and the biomass by plant parts tended to decrease, and the length growth of the shoot part tended to increase slightly, but the root part tended to decrease slightly. The arsenic accumulation concentrations of the shoot and root parts of the 62.5 mg/kg arsenic treatment area were 9.4 mg/kg and 253.3 mg/kg, respectively. While the shoot part of the 250 mg/kg arsenic treatment area withered away, the arsenic accumulation concentration in the root part was analyzed to be 859.1 mg/kg, In the 2,000 mg/kg lead treatment area, the shoot and root parts accumulated 10,308.1 and 11,012.0 mg/kg, which were 1.1 times higher than the root parts. At 100 mg/kg cadmium treatment, the shoot and root parts were 176.0 and 287.2 mg/kg, and the root part accumulated 1.6 times higher than the shoot part. As a result of tolerance evaluation of F. ovina var. coreana, multi-tolerance to three heavy metals was confirmed by maintaining growth without dying in all treatment groups of arsenic, lead, and cadmium. Plant extraction (phytoextraction) of F. ovina var. coreana was verified as a species that can be applied up to 2,000 mg/kg of soil lead contamination.
본 연구는 장기간 중금속 오염에 노출된 폐 석탄매립지에 생육하고 있는 참김의털 (Festuca ovina var. coreana) 종자를 채집하고 발아한 유식물을 가지고 온실 재배 실험을 통해 생육특성과 중금속축적능을 평가하고 식물정화법 (phytoremediation) 적용 가능성을 위해 수행하였다. 참김의털을 온실에서 인공적으로 오염된 토양에서 12 주 동안 재배하였다. 비소처리 인공토양의 농도구배는 각각 25, 62.5, 125, 250 mg/kg, 납 농도는 200, 500, 1000, 2000 mg/kg 및 카드뮴의 농도는 각각 15, 30, 60, 100 mg/kg로 처리하여 실험하였다. 비소, 납 및 카드뮴 처리구에서 참김의털의 엽수는 납 처리구 (200, 500, 1000 mg/kg)를 제외하고 대조구보다 모두 감소하였고, 지상부의 길이 성장은 비소 처리구 모두에서 대조구보다 증가하였으나 지하부는 모두 감소하였고, 1000 및 2000 mg/kg 납 처리구에서는 대조구보다 증가하였으나 나머지 처리구에서는 대조구보다 모두 감소하였고, 카드뮴 처리구의 경우, 지상부는 대조구보다 모두 증가하였고, 지하부는 모두 감소하였다. 비소 처리구의 경우, 생체량은 모든 부위와 모든 농도에서 대조구보다 감소하였고, 200, 500, 1000 mg/kg 납 처리구는 지상부와 지하부 모두에서 대조구보다 생체량이 증가하였고, 카드뮴 처리구에서는 지상부와 지하부의 생체량이 대조군보다 모두 감소하였다. 중금속의 처리구 농도가 높아질수록 엽수와 식물부위별 생체량은 모두 감소하는 경향을 보였고, 중금속의 처리구 농도가 높아질수록 지상부의 길이 성장은 소폭 증가하는 경향이 있으나 지하부는 다소 감소하는 경향이 있었다. 62.5 mg/kg 비소 처리구의 지상부, 지하부의 비소축적농도는 9.4 mg/kg와 253.3 mg/kg로 지하부가 26.9배로 축적율이 높았으며 250 mg/kg 비소 처리구의 지상부는 고사한 반면 지하부의 비소축적농도는 859.1 mg/kg로 분석되었고, 2,000 mg/kg 납 처리구에서 지상부와 지하부는 10,308.1 및 11,012.0 mg/kg로 지상부가 지하부의 1.1배 높게 축적되었고, 100 mg/kg 카드뮴 처리구에서 지상부와 지하부는 176.0 및 287.2 mg/kg로 지하부가 지상부의 1.6배 높게 축적되었다. 참김의털의 내성평가 결과, 비소, 납, 카드뮴의 모든 처리구에서 고사하지 않고 생장을 유지하여 3종의 중금속에 다재내성이 확인되었다. 참김의털의 납 오염토양에 대한 식물추출 (phytoextraction)은 납 오염농도 2,000 mg/kg까지 적용할 수 있는 식물종으로 검증되었다.
