Economic and Environmental Geology (자원환경지질)

The Korean Society of Economic and Environmental Geology (대한자원환경지질학회)
권호 표지
DOI QR코드

DOI QR Code

Spectral Response of Red Lettuce with Zinc Uptake: Pot Experiment in Heavy Metal Contaminated Soil

아연섭취에 따른 적상추의 분광학적 반응: 중금속 오염토양에서의 반응실험

  • Shin, Ji Hye (Department of Astronomy, Space Science and Geology, Chungnam National University) ;
  • Yu, Jaehyung (Department of Geology and Earth Environmental Sciences, Chungnam National University) ;
  • Kim, Jieun (Department of Astronomy, Space Science and Geology, Chungnam National University) ;
  • Koh, Sang-Mo (Convergence research center for development of mineral resources (DMR), Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Bum Han (Convergence research center for development of mineral resources (DMR), Korea Institute of Geoscience and Mineral Resources)
  • 신지혜 (충남대학교 우주.지질학과) ;
  • 유재형 (충남대학교 지질환경과학과) ;
  • 김지은 (충남대학교 우주.지질학과) ;
  • 고상모 (한국지질자원연구원 DMR융합연구단) ;
  • 이범한 (한국지질자원연구원 DMR융합연구단)
  • Received : 2019.01.14
  • Accepted : 2019.04.04
  • Published : 2019.04.28
Download PDF
⟨ Previous Next ⟩

Abstract

This study investigates the spectral response of red lettuce (Lactuca sativa var crispa L.) to Zn concentration. The control group and the experimental groups treated with 1 mM(ZnT1), 5 mM(ZnT2), 10 mM(ZnT3), 50 mM(ZnT4), and 100 mM(ZnT5) were prepared for a pot experiment. Then, Zn concentration and spectral reflectance were measured for the different levels of Zn concentration in red lettuce. The Zn concentration of the control group had the range of 134-181 mg/kg, which was within the normal range of Zn concentration in uncontaminated crops. However, Zn concentration in the experimental group gradually increased with an increase in concentration of Zn injection. The spectral reflectance of red lettuce showed high peak in the red band due to anthocyanin, high reflectance in the infrared band due to the scattering effect of the cell structure, and absorption features associated with water. As Zn concentration in red lettuce leaves increased, the reflectance increased in the green and red bands and the reflectance decreased in the infrared band. The correlation analysis between Zn concentration and spectral reflectance showed that the reflectance of 700-1300 nm had a significant negative correlation with Zn concentration. The spectral band is a wavelength region closely related to the cell structure in the leaf, indicating possible cell destruction of leaf structure due to increased Zn concentration. In particular, 700-800 nm reflectance of the infrared band showed the strongest correlation with the Zn concentration. This study could be used to investigate the heavy metal contamination in soil around mining and agriculture area by spectroscopically recognizing heavy metal pollution of plant.

본 연구는 적상추(Lactuca sativa var crispa L.)가 아연을 축적함에 따라 발생하는 분광학적 반응특성을 고찰하기 위해, 대조군(T0)과 1 mM(ZnT1), 5 mM(ZnT2), 10 mM(ZnT3), 50 mM(ZnT4), 100 mM(ZnT5)로 처리된 실험군을 제작하여 분실험을 실시하였다. 대조군의 아연함량은 134-181 mg/kg의 범위로 오염되지 않은 농작물이 갖는 정상수준의 아연함량을 보였다. 그러나 아연용액의 주입농도가 증가하고 시간이 경과함에 따라 실험군 내 아연함량은 증가하였다. 적상추의 분광반사도는 적색밴드에서 안토시아닌에 의한 높은 피크, 적외선 대역에서 세포구조의 산란효과로 인한 높은 반사도, 그리고 물에 기인한 흡광특성이 관찰되었다. 적상추 내 아연이 고농도로 축적됨에 따라 녹색과 적색밴드에서는 반사도가 증가하고 적외선 대역에서는 반사도가 감소하였다. 아연함량과 분광반사도 사이의 상관관계 분석결과는 700-1300 nm의 파장대역이 아연함량과 유의한 음의 상관관계를 가짐을 보여주었다. 해당 파장대역은 잎 중의 세포구조와 밀접한 관계가 있는 파장대역으로 아연함량이 증가함에 따라 잎 중의 세포구조가 파괴됨을 지시한다. 특히 적외선 대역 중 700-800 nm은 아연함량과 가장 강한 상관관계를 보여주었다. 본 연구는 적상추의 중금속 오염을 분광학적으로 인지하여 광업 및 농업지역 주변 토양 내 중금속 오염을 조사하는데 활용 가능할 것으로 판단된다.

Keywords

JOHGB2_2019_v52n2_129_f0001.png 이미지

Fig. 1. A schematic flow diagram of the methods used in this study.

JOHGB2_2019_v52n2_129_f0002.png 이미지

Fig. 2. Pot experiment setting of red lettuce in six different levels of zinc sulfate heptahydrate injection from 0 to 100 mM. Physiological changes of red lettuce by Zn treatment were tested during pot experiment from September to November 2017.

JOHGB2_2019_v52n2_129_f0003.png 이미지

Fig. 3. The mean reflectance spectra of five experimental groups collected at different levels of Zn concentration with the control group collected in (a) the first week and (b) fifth week of the experiment.

JOHGB2_2019_v52n2_129_f0004.png 이미지

Fig. 4. Foliar reflectance spectra containing chlorophyll+ carotenoids (green line), antocyanin (red line), or a combination of these photosynthetic pigments (black line) (modified from Dunagan et al., 2007; Kochubey and Kazantsev, 2012).

JOHGB2_2019_v52n2_129_f0005.png 이미지

Fig. 5. The reflectance difference between control groups and five different Zn-treated groups collected on fifth week of the experiment: (a) visible-near infrared region from 400 to 1300 nm, and (b) shortwave infrared region from 1300 to 2500 nm.

JOHGB2_2019_v52n2_129_f0006.png 이미지

Fig. 6. A correlogram based on correlation coefficient between foliar Zn concentration and the spectral reflectance. Shaded area corresponds to |r|<0.60.

Table 1. Measurement date conducted in chemical and spectroscopic analyses after injection of Zn solution

JOHGB2_2019_v52n2_129_t0001.png 이미지

Table 2. Zn concentration in red lettuce foliage treated with Zn solution (unit: mg/kg)

JOHGB2_2019_v52n2_129_t0002.png 이미지

Table 3. The statistically significant wavelength to Zn concentration at ZnT4 and ZnT5 groups, the strongest statistically significant wavelength and its correlation coefficient

JOHGB2_2019_v52n2_129_t0003.png 이미지

References

  1. Allaway, W.H. (1968) Agronomic controls over the environmental cycling of trace elements. In Advances in agronomy, Academic Press. v.20, p.235-274. https://doi.org/10.1016/S0065-2113(08)60858-5
  2. Alloway, B.J. (2013) Sources of heavy metals and metalloids in soils. In Heavy metals in soils, Springer, Dordrecht, Netherlands, p.11-50.
  3. Bandaru, V., Hansen, D.J., Codling, E.E., Daughtry, C.S., White-Hansen, S. and Green, C.E. (2010) Quantifying arsenic-induced morphological changes in spinach leaves: implications for remote sensing. International Journal of Remote Sensing., v.31, p.4163-4177. https://doi.org/10.1080/01431161.2010.498453
  4. Boyer, M., Miller, J., Belanger, M., Hare, E. and Wu, J. (1988) Senescence and spectral reflectance in leaves of northern pin oak (Quercus palustris Muenchh.). Remote Sensing of Environment., v.25, n.1, p.71-87. https://doi.org/10.1016/0034-4257(88)90042-9
  5. Brackx, M., Van Wittenberghe, S., Verhelst, J., Scheunders, P. and Samson, R. (2017) Hyperspectral leaf reflectance of Carpinus betulus L. saplings for urban air quality estimation. Environmental Pollution., v.220, p.159-167. https://doi.org/10.1016/j.envpol.2016.09.035
  6. Chang, C.Y., Yu, H. Y., Chen, J.J., Li, F.B., Zhang, H.H. and Liu, C.P. (2014) Accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the Pearl River Delta, South China. Environmental Monitoring and Assessment., v.186, n.3, p.1547-1560. https://doi.org/10.1007/s10661-013-3472-0
  7. Choi, J., Yoo, K., Koo, M. and Park, J.H. (2012) Comparison of Heavy Metal Pollutant Exposure and Risk Assessments in an Abandoned Mine Site. Jurnal of Structures, Construction Management, Nuclear Power, Railroad Engineering., v.32, n.4B, p.261-266.
  8. Choi, J.M., Pak, C.H. and Lee, C.W. (1996) Micro nutrient toxicity in French marigold. Journal of Plant Nutrition., v.19, n.6, p.901-916. https://doi.org/10.1080/01904169609365169
  9. Choi, S.J., Kim, C.H., Lee, S.G. and Kang, I.S. (2010) Analysis of the hazardous RoHS materials in polyethylene and polypropylene samples by benchtop and portable XRF methods. Analytical Science and Technology., v.23, n.1, p.74-82. https://doi.org/10.5806/AST.2010.23.1.074
  10. da Silva, E.D.N., Heerdt, G., Cidade, M., Pereira, C.D., Morgon, N.H. and Cadore, S. (2015) Use of in vitro digestion method and theoretical calculations to evaluate the bioaccessibility of Al, Cd, Fe and Zn in lettuce and cole by inductively coupled plasma mass spectrometry. Microchemical Journal., v.119, p.152-158. https://doi.org/10.1016/j.microc.2014.12.002
  11. Dunagan, S.C., Gilmore, M.S. and Varekamp, J.C. (2007) Effects of mercury on visible/near-infrared reflectance spectra of mustard spinach plants (Brassica rapa P.). Environmental Pollution., v.148, n.1, p.301-311. https://doi.org/10.1016/j.envpol.2006.10.023
  12. Ebbs, S.D. and Kochian, L.V. (1997) Toxicity of zinc and copper to Brassica species: implications for phytoremediation. Journal of Environmental Quality., v.26, n.3, p.776-781. https://doi.org/10.2134/jeq1997.00472425002600030026x
  13. Eitel, J.U., Gessler, P.E., Smith, A.M. and Robberecht, R. (2006) Suitability of existing and novel spectral indices to remotely detect water stress in Populus spp. Forest Ecology and Management., v.229, n.1-3, p.170-182. https://doi.org/10.1016/j.foreco.2006.03.027
  14. Fleming, G.A. and Parle, P.J. (1977) Heavy metals in soils, herbage and vegetables from an industrialised area west of Dublin city. Irish Journal of Agricultural Research., v.16, n.1, p.35-48.
  15. Fontes, R.L.F. and Cox, F.R. (1998) Zinc toxicity in soybean grown at high iron concentration in nutrient solution. Journal of Plant Nutrition., v.21, n.8, p.1723-1730. https://doi.org/10.1080/01904169809365517
  16. Fontes, R.L., Pereira, J. and Neves, J.C. (2014) Uptake and translocation of Cd and Zn in two lettuce cultivars. Anais da Academia Brasileira de Ciencias., v.86, n.2, p.907-922. https://doi.org/10.1590/0001-37652014117912
  17. Gausman, H.W. (1974) Leaf reflectance of near-infrared. Photogrammetric Engineering., v.40, n.2, p.183-91.
  18. Gitelson, A.A., Merzlyak, M.N. and Chivkunova, O.B. (2001) Optical properties and nondestructive estimation of anthocyanin content in plant leaves. Photochemistry and Photobiology., v.74, n.1, p.38-45. https://doi.org/10.1562/0031-8655(2001)074<0038:OPANEO>2.0.CO;2
  19. Grant, L. (1987) Diffuse and specular characteristics of leaf reflectance. Remote Sensing of Environment., v.22, n.2, p.309-322. https://doi.org/10.1016/0034-4257(87)90064-2
  20. Guyot, G., Baret, F. and Jacquemoud, S. (1992) Imaging spectroscopy for vegetation studies. In: Toselli F, Bodenchtel J, (ed.) Imaging spectroscopy: Fundamentals and prospective application, 2, Kluwer Academic, Dordrecht, p.145-165.
  21. Intawongse, M. and Dean, J.R. (2006) Uptake of heavy metals by vegetable plants grown on contaminated soil and their bioavailability in the human gastrointestinal tract. Food Additives and Contaminants., v.23, n.1, p.36-48. https://doi.org/10.1080/02652030500387554
  22. Jeong, Y., Yu, J., Wang, L. and Shin, J.H. (2018) Spectral Responses of As and Pb Contamination in Tailings of a Hydrothermal Ore Deposit: A Case Study of Samgwang Mine, South Korea. Remote Sensing., v.10, n.11, p.1830. https://doi.org/10.3390/rs10111830
  23. Jung, G.B., Kim, W.I., Lee, J.S., Lee, J.S., Park, C.W. and Koh, M.H. (2005) Characteristics of heavy metal contamination in residual mine tailings near abandoned metalliferous mines in Korea. Korean Journal of Environmental Agriculture., v.24, n.3, p.222-231. https://doi.org/10.5338/KJEA.2005.24.3.222
  24. Jung, M.C. (2008) Heavy metal concentrations in soils and factors affecting metal uptake by plants in the vicinity of a Korean Cu-W mine. Sensors., v.8, n.4, p.2413-2423. https://doi.org/10.3390/s8042413
  25. Kim, J.D. (2005). Assessment of Pollution Level and Contamination Status on Mine Tailings and Soil in the Vicinity of Disused Metal Mines in Kangwon Province. Journal of Korean Societry of Environmental Engineers, v.27, n.6, p.626-634.
  26. Kochubey, S.M. and Kazantsev, T.A. (2012) Derivative vegetation indices as a new approach in remote sensing of vegetation. Frontiers of Earth Science., v.6, n.2, p.188-195. https://doi.org/10.1007/s11707-012-0325-z
  27. Kupkova, L., Potuckova, M., Zachova, K., Lhotakova, Z., Kopackova, V. and Albrechtova, J. (2012) Chlorophyll Determination in silver birch and scots pine foliage from heavy metal polluted regions using spectral reflectance data. EARSeL E-Proceedings., v.11, p.64-73.
  28. Lawryk, N.J., Feng, H.A. and Chen, B.T. (2009) Laboratory evaluation of a field-portable sealed source X-ray fluorescence spectrometer for determination of metals in air filter samples. Journal of Occupational and Environmental Hygiene., v.6, n.7, p.433-445. https://doi.org/10.1080/15459620902932119
  29. Li, X., Liu, X., Liu, M., Wang, C. and Xia, X. (2015) A hyperspectral index sensitive to subtle changes in the canopy chlorophyll content under arsenic stress. International Journal of Applied Earth Observation and Geoinformation., v.36, p.41-53. https://doi.org/10.1016/j.jag.2014.10.017
  30. Lim, J.H., Yu, J., Shin, J.H., Jeong, Y., Koh, S.M. and Park, G. (2017) Heavy Metal Contamination Characteristics and Spectral Characteristics of White Precipitation occurring at Miin Falls Drainage. Journal of the mineralogical society of Korea., v.30, n.1, p.31-43. https://doi.org/10.9727/jmsk.2016.30.1.31
  31. Lim, J.H., Yu, J., Bae, S., Koh, S.M. and Park, G. (2018) Heavy Metal Contamination, Mineral Composition and Spectral Characteristics of Reddish Brown Precipitation Occurring at Osip Stream Drainage, Gangwon-do. Journal of the Mineralogical Society of Korea., v.31, n.2, p.75-86. https://doi.org/10.9727/jmsk.2018.31.2.75
  32. Luo, C., Liu, C., Wang, Y., Liu, X., Li, F., Zhang, G. and Li, X. (2011) Heavy metal contamination in soils and vegetables near an e-waste processing site, south China. Journal of Hazardous Materials., v.186, n.1, p.481-490. https://doi.org/10.1016/j.jhazmat.2010.11.024
  33. Macnicol, R.D. and Beckett, P.H.T. (1985) Critical tissue concentrations of potentially toxic elements. Plant and Soil., v.85, n.1, p.107-129. https://doi.org/10.1007/BF02197805
  34. Melo, L.C.A., Alleoni, L.R.F., Swartjes, F.A. and da Silva, E.B. (2012) Cadmium uptake by lettuce (Lactuca sativa L.) as basis for derivation of risk limits in soils. Human and Ecological Risk Assessment: An International Journal., v.18, n.4, p.888-901. https://doi.org/10.1080/10807039.2012.688716
  35. Mench, M., Vangronsveld, J., Didier, V. and Clijsters, H. (1994) Evaluation of metal mobility, plant availability and immobilization by chemical agents in a limed-silty soil. Environmental Pollution., v.86, n.3, p.279-286. https://doi.org/10.1016/0269-7491(94)90168-6
  36. Mimuro, M. and Katoh, T. (1991) Carotenoids in photosynthesis: absorption, transfer and dissipation of light energy. Pure and Applied Chemistry., v.63, n.1, p.123-130. https://doi.org/10.1351/pac199163010123
  37. Myers, V.I. and Allen, W.A. (1968) Electrooptical remote sensing methods as nondestructive testing and measuring techniques in agriculture. Applied Optics., v.7, n.9, p.1819-1838. https://doi.org/10.1364/AO.7.001819
  38. Nagajyoti, P.C., Lee, K. D. and Sreekanth, T.V.M. (2010) Heavy metals, occurrence and toxicity for plants: a review. Environmental Chemistry Letters., v.8, n.3, p.199-216. https://doi.org/10.1007/s10311-010-0297-8
  39. Neill, S.O., Gould, K.S., Kilmartin, P.A., Mitchell, K.A. and Markham, K.R. (2002) Antioxidant activities of red versus green leaves in Elatostema rugosum. Plant, Cell & Environment., v.25, n.4, p.539-547. https://doi.org/10.1046/j.1365-3040.2002.00837.x
  40. Nicholson, F.A., Smith, S.R., Alloway, B.J., Carlton-Smith, C. and Chambers, B.J. (2003) An inventory of heavy metals inputs to agricultural soils in England and Wales. Science of the Total Environment., v.311, n.1-3, p.205-219. https://doi.org/10.1016/S0048-9697(03)00139-6
  41. Penuelas, J. and Filella, I. (1998) Visible and near-infrared reflectance techniques for diagnosing plant physiological status. Trends in Plant Science., v.3, n.4, p.151-156. https://doi.org/10.1016/S1360-1385(98)01213-8
  42. Podar, D. and Ramsey, M.H. (2005) Effect of alkaline pH and associated Zn on the concentration and total uptake of Cd by lettuce: comparison with predictions from the CLEA model. Science of the Total Environment., v.347, n.1-3, p.53-63. https://doi.org/10.1016/j.scitotenv.2004.11.024
  43. Pu, R., Ge, S., Kelly, N.M. and Gong, P. (2003) Spectral absorption features as indicators of water status in coast live oak (Quercus agrifolia) leaves. International Journal of Remote Sensing., v.24, n.9, p.1799-1810. https://doi.org/10.1080/01431160210155965
  44. Queralt, I., Ovejero, M., Carvalho, M.L., Marques, A.F. and Llabres, J.M. (2005) Quantitative determination of essential and trace element content of medicinal plants and their infusions by XRF and ICP techniques. X-Ray Spectrometry: An International Journal., v.34, n.3, p.213-217. https://doi.org/10.1002/xrs.795
  45. Rathod, P.H., Rossiter, D.G., Noomen, M.F. and Van der Meer, F.D. (2013) Proximal spectral sensing to monitor phytoremediation of metal-contaminated soils. International Journal of Phytoremediation., v.15, n.5, p.405-426. https://doi.org/10.1080/15226514.2012.702805
  46. Reidinger, S., Ramsey, M.H. and Hartley, S.E. (2012) Rapid and Accurate Analyses of Silicon and Phosphorus in Plants Using a Portable X-Ray Fluorescence Spectrometer. New Phytologist., v.195, n.3, p.699-706. https://doi.org/10.1111/j.1469-8137.2012.04179.x
  47. Rosso, P.H., Pushnik, J.C., Lay, M. and Ustin, S.L. (2005) Reflectance properties and physiological responses of Salicornia virginica to heavy metal and petroleum contamination. Environmental Pollution., v.137, n.2, p.241-252. https://doi.org/10.1016/j.envpol.2005.02.025
  48. Sacristan, D., Rossel, R.A.V. and L. Recatala. (2016) Proximal Sensing of Cu in Soil and Lettuce Using Portable X-Ray Fluorescence Spectrometry. Geoderma., v.265, p.6-11. https://doi.org/10.1016/j.geoderma.2015.11.008
  49. Sauerbeck, D.R. (1991) Plant element and soil properties governing uptake and availability of heavy metals derived from sewage sludge. Water, Air, and Soil Pollution., v.57, n.1, p.227-237. https://doi.org/10.1007/BF00282886
  50. Shi, T., Liu, H., Wang, J., Chen, Y., Fei, T. and Wu, G. (2014) Monitoring arsenic contamination in agricultural soils with reflectance spectroscopy of rice plants. Environmental Science & Technology., v.48, n.11, p.6264-6272. https://doi.org/10.1021/es405361n
  51. Shin, H., Yu, J., Jeong, Y., Wang, L., and Yang, D.Y. (2017) Case-Based Regression Models Defining the Relationships Between Moisture Content and Shortwave Infrared Reflectance of Beach Sands. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing., v.10, n.10, p.4512-4521. https://doi.org/10.1109/JSTARS.2017.2723912
  52. Shin, J.H., Yu, J., Jeong, Y., Kim, S., Koh, S.M. and Part, G. (2016) Spectral Characteristics of Heavy Metal Contaminated Soils in the Vicinity of Boksu Mine. Journal of the Mineralogical Society of Korea., v.29, n.3, p.89-101. https://doi.org/10.9727/jmsk.2016.29.3.89
  53. Sinclair, T.R., Schreiber, M.M. and Hoffer, R.M. (1973) Diffuse Reflectance Hypothesis for the Pathway of Solar Radiation Through Leaves 1. Agronomy Journal., v.65, n.2, p.276-283. https://doi.org/10.2134/agronj1973.00021962006500020027x
  54. Slonecker, T., Haack, B. and Price, S. (2009) Spectroscopic analysis of arsenic uptake in Pteris ferns. Remote Sensing., v.1, p.644-675. https://doi.org/10.3390/rs1040644
  55. Sridhar, B.M., Han, F.X., Diehl, S.V., Monts, D.L. and Su, Y. (2007) Spectral reflectance and leaf internal structure changes of barley plants due to phytoextraction of zinc and cadmium. International Journal of Remote Sensing., v.28, n.5, p.1041-1054. https://doi.org/10.1080/01431160500075832
  56. Tang, X., Pang, Y., Ji, P., Gao, P., Nguyen, T.H. and Tong, Y.A. (2016) Cadmium uptake in above-ground parts of lettuce (Lactuca sativa L.). Ecotoxicology and Environmental Safety., v.125, p.102-106. https://doi.org/10.1016/j.ecoenv.2015.11.033
  57. Thenkabail, P.S., Mariotto, I., Gumma, M.K., Middleton, E.M., Landis, D.R. and Huemmrich, K.F. (2013) Selection of hyperspectral narrowbands (HNBs) and composition of hyperspectral twoband vegetation indices (HVIs) for biophysical characterization and discrimination of crop types using field reflectance and Hyperion/EO-1 data. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing., v.6, n.2, p.427-439. https://doi.org/10.1109/JSTARS.2013.2252601
  58. Ulmanu, M., Anger, I., Gament, E., Mihalache, M., Plopeanu, G. and Ilie, L. (2011) Rapid determination of some heavy metals in soil using an X-ray fluorescence portable instrument. Research Journal of Agricultural Science., v.43, n.3, p.235-241.
  59. Wang, F., Gao, J. and Zha, Y. (2018) Hyperspectral sensing of heavy metals in soil and vegetation: Feasibility and challenges. ISPRS Journal of Photogrammetry and Remote Sensing., v.136, p.73-84. https://doi.org/10.1016/j.isprsjprs.2017.12.003
  60. Weindorf, D.C., Zhu, Y., Chakraborty, S., Bakr, N. and Huang, B. (2012a) Use of portable X-ray fluorescence spectrometry for environmental quality assessment of peri-urban agriculture. Environmental Monitoring and Assessment., v.184, n.1, p.217-227. https://doi.org/10.1007/s10661-011-1961-6
  61. Weindorf, D.C., Zhu, Y., McDaniel, P., Valerio, M., Lynn, L., Michaelson, G., Clarke, M. and Ping, C. L. (2012b). Characterizing soils via portable x-ray fluorescence spectrometer: 2. Spodic and Albic horizons. Geoderma., v.189, p.268-277. https://doi.org/10.1016/j.geoderma.2012.06.034
  62. Woolley, J.T. (1971) Reflectance and transmittance of light by leaves. Plant Physiology., v.47, n.5, p.656-662. https://doi.org/10.1104/pp.47.5.656
  63. World Health Organization (WHO) (2001) Environmental Health Criteria for Zinc, Available from: http://www.inchem.org/documents/ehc/ehc/ehc221.htm. Accessed 2004 September 13
  64. Zhu, Y., An, F. and Tan, J. (2011) Geochemistry of hydrothermal gold deposits: a review. Geoscience Frontiers., v.2, n.3, p.367-374. https://doi.org/10.1016/j.gsf.2011.05.006