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Päivi Joki-Heiskala Matti Johansson Maria Holmberg Tuija Mattsson Martin Forsius Pirkko Kortelainen Lena Hallin 《Water, air, and soil pollution》2003,150(1-4):255-273
Long-term base cation balances (Ca, Mg and K) for forest mineral soils in Finland were calculated with mass balance methods. The aim of the study was to identify the areas in which weathering and base cation deposition do not support leaching and uptake of base cations by vegetation. The effect of stem harvesting and whole-tree harvesting on the base cation balances was studied and preliminary calculations were made about the amounts of ash needed for compensation of the potential base cation depletion. The effect of sulphur emission reduction till 2010 was also considered. The study demonstrated that there would be depletion of base cations in forest mineral soils in southern, central and northeastern Finland (40–50% of the grids) in the long term if whole-tree harvesting would be practised. Theoretical calculations showed that ash application would be most useful in those areas to compensate the base cation depletion. If stem harvesting is practised, only small areas (20%) in southwestern and southeastern Finland and northeastern Lapland would show depletion of base cations in the long term. 相似文献
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P. Kortelainen J. Mannio M. Forsius J. Kamari M. Verta 《Water, air, and soil pollution》1989,46(1-4):235-249
A lake survey consisting of 987 randomly selected lakes was conducted in Finland in autumn 1987. The survey covered the whole country, and the water quality of the lakes can be considered as representative of the approximately 56 000 lakes larger than 0.01 km2 in Finland. The median TOC concentration is 12 mg L-1 and the median pH 6.3. The proportion of lakes with TOC concentrations > 5 mg L-1 in the whole country is 91 %. Organic anion is the main anion in the full data set (median 89 μeq L-1). The high organic matter concentrations in Finnish lakes are associated with catchment areas containing large proportions of peatlands and acid organic soils under coniferous forest. The survey demonstrated that organic matter strongly affects the acidity of lakes in Finland. The decreasing effect of organic matter on the pH values was demonstrated by both regression analysis and ion balances. At current deposition levels of *SO4 the pH of humic lakes in Finland is determined to a greater extent by high TOC concentrations than by *SO4 in most areas. In lakes with pH values lower than 5.5 the average organic anion contribution is 56 % and non-marine sulfate contribution 39 %. However, in the southern parts of the country, where the acidic deposition is highest, the minerogenic acidity commonly exceeds the catchment derived organic acidity. 相似文献
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This study provides an assessment of the spatial variability of the long-term leaching of nutrients, total organic carbon (TOC) and iron (Fetot) from 22 forested catchments (0.69-56 km2), distributed across all but the northenmost areas of Finland. The natural, unmanaged Kruunuoja catchment is located in a national park, while the other catchments represent Finnish forestry land. The average leaching of Ptot (4.2 kg km-2 yr-1) from the Kruunuoja catchment was small compared to the catchments representing forestry land (on average 10 kg km-2 yr-1). Moreover, P fertilization was the most important predictor for the spatial variation in Ptot leaching (r2=0.45). Leaching of TOC, Fetot and N compounds was not closely related to forestry practices. Median C/N ratio in the study streams was high (range 34-66). The average inorganic N proportion and leaching of Ptot were lowest in the Kruunuoja catchment (7.3 % and 2.8 kg km-2 yr-1, respectively) and highest in the southernmost Teeressuonoja catchment (54 % and 100 kg km-2 yr-1, respectively) located in the highest N deposition area. The most important forestry practices since the 1960's have affected about 2.4 % of the area of study sites per year (cf. 2% in the entire country in 1991). Moreover, the mean annual runoff from the catchments (230-430 mm yr-1) agrees with the mean annual runoff from Finland (301 mm yr-1). Consequently, the results of the study catchments can be used to estimate average total annual leaching from Finnish forestry land: 2,700 t of Ptot, 48,000 t of Ntot, 110,000 t of Fetot and 1.5 million t of TOC. 相似文献
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This study provides an assessment of the transport of organic carbon and organic acids from typical Finnish forested catchments since the 1960's. The 21 study catchments (0.69–56 km2) are located over Finland excluding the northernmost regions. The mean annual total organic carbon (TOC) load from the catchments ranges from 2 600 to 8 800 kg/km2/a. Using a total acidity of 9.7 eq/mg DOC this would represent organic acid load of about 25–85 keq/km2/a which is higher than the mean annual deposition of strong acids in the highest deposition areas in southern Finland. The study demonstrates that organic acids dominate stream water acidity over large regions in Finland. In southern Finland minerogenic acidity is, however, more important. Organic acids exceeded mineral acids not only in autumn but also during spring snowmelt in 18 catchments. Moreover, the lowest pH values (25th percentile) were dominated by organic acids in 20 catchments. In most catchments TOC better explained pH than non-marine sulphate. In stepwise multiple regression base cations and TOC explained 67–83 % of the variation in pH for catchments divided into six groups according to season, deposition and peatland percentage; non-marine sulphate had minor contribution. 相似文献
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The headwater lakes in peat-rich areas in Finland commonly have high organic matter concentrations and are surrounded by soils and bedrock poor in bases. As a result the organic acid load on the watercourses is generally high. The significance of the organic vs anthropogenic acidity in 78 moderately acid lakes (pH range 4.3 to 7.1, TOC range 0.6 to 33.9 mg L?1) was evaluated in areas receiving different levels of acid deposition. The lakes were sampled during autumn overturn, and their water quality (mean TOC = 10.9 mg L?1, mean pH = 5.9) represents rather well the average water quality in small lakes in Finland. According to the correlation and regression analyses, TOC is a better predictor of pH than non-marine sulfate. Base cation concentrations are important in determining the sensitivity of the lakes to organic and anthropogenic acidity. The highest minerogenic acid contribution is found in high-deposition areas, while the percent organic acid contribution is greater in low deposition areas although TOC levels are comparable in both areas. It would appear that the pH of humic lakes is determined to a greater extent by individual watershed characteristics than by their geographical location at the present atmospheric loadings received in Finland. 相似文献
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Organic vs. bicarbonate contribution to Gran alkalinity was studied using empirical measurements. Distilled water with various amounts of bicarbonate and organic acids was equilibrated with synthetic air during Gran titrations. Natural organic acids isolated from Finnish lakes were used as a carbon source for these solutions. The experimental design corresponded to computer simulations made by Cantrell et al. (1990). The results indicate that the discrepancy between the Gran ANC and the ANC calculated from anion deficit can be explained partly by the organic acids, which remain unprotonated in the titration. The unprotonated fraction of organic acids was on average 5.5 and 6.2 eq per mg of dissolved organic carbon (DOC), when pH ranges of 3.0–4.0 and 3.5–4.5 for Gran plot regression were used, respectively. The acid neutralizing capacity provided by organic acids varied from 18 to 75 eq/L, depending on the initial pH and DOC concentration and the pH range of the Gran plot regression. The results of empirical Gran titrations agree with the theoretical calculations made by Cantrell et al. (1990). 相似文献
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Mattsson Tuija Finér Leena Kortelainen Pirkko Sallantaus Tapani 《Water, air, and soil pollution》2003,147(1-4):275-298
The water chemistry of 21 outlet brooks in undisturbed, forested catchments (0.074–38 km2) in Finland was monitored during three years (1997–1999) in order to estimate the background levels and leaching of total organic carbon (TOC), iron, nitrogen and phosphorus, and examine the relationships between catchment characteristics and brook water quality in pristine forested areas. The studied catchments are located throughout Finland except the northernmost parts of the country. The concentrations of TOC were relatively high, on average 20 mg L-1. Annual leaching of TOC ranged from 3000 to 10 000 kg km-2. The average total nitrogen concentration and annual leaching were 430 μg L-1 and 140 kg km-2, respectively. The average total phosphorus concentration and annual leaching were 15 μg L-1 and 5.4 kg km-2, respectively. On a national level temperature and discharge conditions were the most important variables for predicting total phosphorus, total nitrogen and TOC concentrations. Both total nitrogen and total phosphorus concentrationsdisplayed positive correlation with temperature, and thus the concentrations were higher in the south than in the north. Nitrogen was mainly organic and showed strong correlation with TOC. On the catchment level, both TOC and total nitrogen concentrations and export had a strongpositive correlation with the abundance of Norway spruce (Piceaabies Karsten) and a strong negative correlation with the abundance of Scots pine (Pinus sylvestris L.). Nitrate concentrations and leaching were related to average site type. The more fertile the average site type was in the catchment, the higher the nitrate concentrations and export were. 相似文献
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