Model Development on the Fate and Transport of Chemical Species in Marsh Wetland Sediments Considering the Effects of Plants and Tides

식생과 조석의 영향을 고려한 연안습지 퇴적물 내 물질거동 모형의 개발

  • Park, Do-Hyun (Department of Energy Resources Engineering, Pukyong National University) ;
  • Wang, Soo-Kyun (Department of Energy Resources Engineering, Pukyong National University)
  • 박도현 (부경대학교 에너지자원공학과) ;
  • 왕수균 (부경대학교 에너지자원공학과)
  • Received : 2009.10.07
  • Accepted : 2009.11.30
  • Published : 2009.12.31

Abstract

Wetlands can remove organic contaminants, metals and radionuclides from wastewater through various biogeochemical mechanisms. In this study, a mathematical model was developed for simulating the fate and transport of chemical species in marsh wetland sediments. The proposed model is a one-dimensional vertical saturated model which is incorporated advection, hydrodynamic dispersion, biodegradation, oxidative/reductive chemical reactions and the effects from external environments such as the growth of plants and the fluctuation of water level due to periodic tides. The tidal effects causes periodic changes of porewater flow in the sediments and the evapotranspiration and oxygen supply by plant roots affect the porewater flow and redox condition on in the rhizosphere along with seasonal variation. A series of numerical experiments under hypothetical conditions were performed for simulating the temporal and spatial distribution of chemical species of interests using the proposed model. The fate and transport of a trace metal pollutant, chromium, in marsh sediments were also simulated. Results of numerical simulations show that plant roots and tides significantly affect the chemical profiles of different electron acceptors, their reduced species and trace metals in marsh sediments.

습지는 다양한 생지화학적 반응기작을 통하여 폐수로부터 유입되는 유기오염물질을 완화/정화하는 지역으로 알려져있다. 본 연구에서는 습지에서 다양한 물질의 성상과 거동을 모의하기 위하여 수학적 모형을 개발하였다. 개발한 모형은 1차원 수직 포화 모형으로 이류, 수리학적 분산, 미생물에 의한 생분해, 산화/환원반응, 식생과 조수 등 외부환경의 영향을 고려하였다. 조수의 영향은 퇴적물 내 공극수의 흐름에 주기적인 변화를 일으키고, 계절에 따라 식생은 증발산과 뿌리로부터의 산소공급을 통해 흐름과 근권 내 산화/환원 환경에 영향을 미친다. 개발된 모형을 적용하여 습지퇴적물 내에 존재하는 관심물질의 공간적 및 시간적 분포 모의를 위한 가상의 수치실험을 수행하였다. 또한 대표적인 중금속 오염물질의 하나인 크롬의 습지퇴적물 내 성상과 거동을 모의하였다. 모의 결과는 식생 뿌리와 조수가 습지퇴적물 내 전자수용체, 환원물질, 중금속의 분포에 지대한 영향을 미칠 수 있음을 보여주었다.

Keywords

References

  1. Armstrong, W., 1979, Aeration in higher plants. Adv. Bot. Res., 7, 225-232 https://doi.org/10.1016/S0065-2296(08)60089-0
  2. Bartlett, R.J., 1991, Chromium cycling in soils and water: links, gaps, and methods. Environ. Health Perspect., 92, 17-24 https://doi.org/10.2307/3431133
  3. Bedford, B.L., Bouldin, D.R., and Beliveau, B.D., 1991, Net oxygen and carbon-dioxide balances in solutions bathing roots of wetland plants, J. Ecol., 79, 943-959 https://doi.org/10.2307/2261090
  4. Brix, H., Sorrell, B.K., and Schierup, H.H., 1996, Gas fluxes achieved by in situ convective flow in Phragmites australis, Aquat. Bot., 54, 151-163 https://doi.org/10.1016/0304-3770(96)01042-X
  5. Choi, J.H., Park, S.S., and Jaffe, P.R., 2006, Simulating the dynamics of sulfur species and zinc in wetland sediments, Ecol. Model., 199, 315-323 https://doi.org/10.1016/j.ecolmodel.2006.05.009
  6. DiToro, D.M., 2001, Sediment Flux Modeling, John Wiley & Sons, Inc., Hoboken, NJ, p.656
  7. Fendorf, S.E. and Li, G., 1996, Kinetic of chromate reduction by ferrous iron, Environ. Sci. Technol., 30, 1614-1617 https://doi.org/10.1021/es950618m
  8. Fendorf, S.E., Li, G., and Gunter, M.E., 1996, Micromorphologies and stabilities of chromium(III) surface precipitates elucidated by scanning force microscopy, Soil Sci. Soc. Am. J., 60, 99-106 https://doi.org/10.2136/sssaj1996.03615995006000010017x
  9. Grosse, W., 1997, Gas transport in trees, In: H. Tenneverg, W. Eschrich, and H. Ziegler (eds.), Contributions to Modern Tree Physiology, Backhuys Publishers, Leiden, 57-74
  10. Jaffe, P.R., Wang, S., Kallin, P.L. and Smith L.S., 2002, The dynamics of arsenic in saturated porous media: fate and transport modeling for deep aquatic sediments, wetland sediments, and groundwater environments, In: R. Hellmann and S.A. Wood (eds.), Water-Rock Interactions, Ore Deposits, and Environmental Geochemistry: A Tribute to David A. Crerar, Geochemical Society, St. Louis, 379-397
  11. Katz, S.A. and Salem, H., 1993, The toxicology of chromium with respect to its chemical speciation: a review, J. Appl. Toxicol., 13, 217-224 https://doi.org/10.1002/jat.2550130314
  12. Ok, Y.S., Jung, J., Lee, H., Song, H., Jung, N., Lim, S., and Kim, J.G., 2004, Chemical characterization and bioavailability of cadmium in artificially and naturally contaminated soils, Agr. Chem. Biotechnol., 47, 143-146
  13. Sand-Jensen, K., Prahl, C., and Stokholm, H., 1982, Oxygen release from roots of submerged aquatic macrophytes, Oikos, 38, 349-354 https://doi.org/10.2307/3544675
  14. Vanishtein, M., Kuschk, P., Mattusch, J., Vatsourina, A., and Wiessner, A., 2003, Model experiments on the microbial removal of chromium from contaminated groundwater, Water Res., 37, 1401-1405 https://doi.org/10.1016/S0043-1354(02)00455-4