| Analyses of forest floor humus |
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ANALYSES OF FOREST FLOOR HUMUS Forest floor humus ( Fig. 1) accumulates atmospheric deposition loads over a long period of time. The adsorption capacity of humus matter can exceed even 550 meq.100g-1. For this reason, forest floor humus can serve as a suitable indicator of integrated atmospheric deposition loads for a period at least as long as the current age of the forest. We have used forest floor humus as a long-term indicator of environmental pollution in the following major projects:
• Training methods for collecting and analysing forest humus (1992–1994) We have suggested and validated methods for collecting and analysing forest floor humus (Oh). Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mo, Ni, Pb, S, V and Zn have been repeatedly determined in litter (Ol), in the fermentation horizon (Of), in the humification horizon (Oh) and in organo-mineral soil (Ah/A) using the AAS and ICP-OES technique. We used nine coniferous forests variously affected by atmospheric deposition levels for the tests ([1], [2], Fig. 2). [1] Suchara I. et al. (1993): Určení úrovně znečištění významných lesních oblastí ČR kovy pomocí analýzy mechů a lesního humusu.- Výr. Zpr., Projekt MŽP GA/1171/93, ms., VÚOZ Průhonice, 37 p. [2] Suchara I. et al.(1994): Určení úrovně znečištění významných lesních oblastí ČR kovy pomocí analýzy mechů a lesního humusu.- Výr. Zpr., Projekt MŽP ČR GA/1171/93, ms., VÚOZ Průhonice, 57 p.
• Determining element concentrations in forest floor humus in the Czech Republic (1995–1996) We collected specimens of forest floor humus (Oh) at 192 monitoring plots in coniferous forests evenly spread over the Czech Republic. We determined the concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, S, V and Zn by OES-ICP after digestion of samples in HNO3+H2O2 and we directly determined the total Hg in powdered humus, using AMA 254. We also determined the reaction of humus extracts (pH-H2O and pH-CaCl2) and loss-on-ignition. We presented the results in a national humus survey ([3], Fig. 3 and Fig. 4) and the summary results in a paper [4]. [3] Suchara I., Sucharová J. (2000): Distribution of long-term accumulated atmospheric deposition loads of metal and sulphur compounds in the Czech Republic determined through forest floor humus analyses.- Acta Průhoniciana, 69: 1–178. [4] Suchara I., Sucharová J. (2002): Distribution of sulphur and heavy metals in forest floor humus of the Czech Republic.- Water, Air Soil Pollut. 136: 289–316.
• Determining the long-term accumulated metal depositions in humus near a lead smelter outside Příbram (1999) We collected humus samples at 56 sites within a 14-km radius around the Kovohutě Příbram secondary lead smelter. We determined the concentrations of Ag, Al, As, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hg, In, La, Li, Mn, Mo, Ni, Pb, Pr, Rb, S, Sb, Se, Sn, Sr, Th, Tl, U, V, W, Y and Zn in forest floor humus digested by HNO3+H2O2, using ICP-MS and OES-ICP. The total N and Hg were detected directly in the solid humus samples (Kljeldahl, CN analyser). We determined the reaction of the humus extracts (pH) and the portion of organic matter (loss-on-ignition) in the samples. We found high concentrations of, for example, Ag, Cd, Hg, Cr, In, Pb, Sb and Zn around the smelter, and an additional hot spot of high accumulation of terrigenic elements (e.g., Al, Ce, lanthanides, U) was revealed around a mill for grinding stones from the former uranium pits. We found a zone of increased molybdenum accumulation near Komárov (the BUZULUK piston ring production plant). For details, see, e.g. [5], [6] and Fig. 5. [5] Sucharová J. et al. (1999): Multielementární analýzy mechu a humusu v okolí Příbrami.- Dílčí Záv. Zpr., Projekt VaV/610/3/97, ms., VÚOZ Průhonice, 104 p. [6] Suchara I., Sucharová J. (2004): Distribution of 36 element deposition rates in a historic mining and smelting area as determined through fine-scale biomonitoring techniques. Part II: Relative long-term accumulated atmospheric deposition levels.- Water, Air Soil Pollut. 153: 229–252.
• A survey of element concentrations in forest floor humus in south Moravia (2002–2003) In south Moravia between Brno, Kroměříž and Břeclav there is an area suffering from intensive wind erosion. We investigated the element composition of forest floor humus (Oh) affected by heavy deposition loads of soil particles at about 30 sites. We determined the concentrations of Ag, Al, As, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hg, In, La, Li, Mn, Mo, Ni, Pb, Pr, Rb, S, Sb, Se, Sn, Sr, Th, Tl, U, V, W, Y and Zn in humus digested in HNO3+H2O2 ,using (OES-ICP, ICP-MS) or directly in powdered samples (mercury by AMA 254). A high accumulation of terrigenic elements in humus in the area was confirmed ([7], [8] and Fig. 6). [7] Sucharová J. et al. (2002): Biomonitorování obsahu 35 prvků v mechu a humusu jako podklad pro upřesnění distribuce vysokých atmosférických úrovní spadu na jižní Moravě.- Výr. Zpr., Projekt VaV/640/1/00, ms., VÚKOZ Průhonice, 32 p. [8] Sucharová J. et al. (2003): Stanovení obsahu prvků v půdě a mechu jako podklad pro upřesnění distribuce vysokých atmosférických úrovní spadu sledovaných prvků na jižní Moravě.- Výr. Zpr., Projekt VaV/640/1/00, ms., VÚKOZ Průhonice, 116 p.
• Determining mercury accumulation in humus around the Spolana chlor-alkali plant, Neratovice (2004) In a 12-km radius around the Spolana chlor-alkali plant, which was flooded in 2002, we determined the total Hg content in forest floor humus samples collected in flooded and non-flooded areas, using an AMA 254 Hg analyser. The pattern of Hg distribution in humus was similar to the patterns of the Hg concentration distributions in moss and oak bark (Fig. 4.5 and Fig. 5.5), which were analysed in parallel ([9], [10] and Fig. 7). [9] Sucharová J., Suchara I. (2004): Sledování aktuálních, starých a dlouhodobých zátěží území atmosférickými depozicemi pomocí analýz mechu a nadložního humusu.- Výr. Zpr., Projekt 0212, MZPN0102, ms., VÚOZ Průhonice, 21 p. [10] Suchara I., Sucharová J. (2008): Mercury distribution around the Spolana chlor-alkali plant (central Bohemia, Czech Republic) after a catastrophic flood, as revealed by bioindicators.- Environ. Poll. 151: 352–361.
• Total content of elements in forest floor humus in coniferous forests in the Czech Republic (2008-2010) We collected samples of forest floor humus at 159 forest stands evenly distributed throughout the Czech Republic. We determined the concentrations of Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Hg, K, La, Li, Mg, Mn, Mo, N, Na, Nd, Ni, Pb, Pr. Rb, S, Sb, Se, Sn, Sr, Th, Tl, U, V, Y and Zn after digestion in HNO3+H2O2+HF+H3BO3 using ICP-MS and OES-ICP, and total Hg and nitrogen were determined directly, using AMA 254 and a CN analyser (Fig. 8). We measured the reaction of humus extracts (pH-H2O and pH-CaCl2) and the content of organic matter in the humus (loss-on-ignition). The investigations are carried out in the framework of international project CZ0074.
• Determining 137Cs retention in forest floor humus in coniferous forests in the Czech Republic (2010-2011) The archived samples of forest floor humus (H, Oh) collected from 190-250 forest monitoring plots in the monitoring campaigns in 1995 a 2005 were provided to the National Radiation Protection Institute in Prague for determination of Chernobyl derived 137Cs activities in forest humus maintained up to present. Considerably increased and long-term accumulation of 137Cs in forest floor humus (Oh/Ah interface) was detected in areas affected by precipitation when the Chernobyl plumes were passing the country in April/May 1986. Wet deposition was the most effective way of the air-borne 137Cs deposition in 1986 ([11], [12], Fig. 9). [11] Pilátová H. et al. (2011): Maps of 137Cs content in forest humus in the Czech Republic in 1995.-In Czech. Report: Zpráva SÚRO č. 25/2011, SÚRO Praha, 8 p. [12] Pilátová H. et al. (2011): Maps of 137Cs content in forest humus in the Czech Republic in 2005.-In Czech.- Report: Zpráva SÚRO č. 26/2011, SÚRO Praha, 8 p. |