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Trace elements in the hydrologic cycle of a forest ecosystem
Abstract
Concentrations of Cu, Fe, Mn, and Zn were measured in bulk atmospheric precipitation, throughfall, stemflow, and soil solutions
at 10−, 15−, 25−, and 30-cm depths, in aEucalyptus globulus forest in the Berkeley hills, California, during the 1974–75 wet season after each main storm event. Litter and plant samples
were analyzed. There was some similarity in the behavior of Cu, Fe, and Zn, but Mn behaved differently. Mn and Zn are largely
deposited on the forest canopy by impaction during dry-deposition episodes, whereas most of the Cu and Fe input occurs in
rain. For the hydrologic components measured, concentrations of Cu and Fe increase in the order: precipitation<throughfall<stemflow
<soil solutions. For Zn the order is: precipitation<stemflow<throughfall<soil solutions. Concentrations of Cu, Zn, and Fe
in the soil solution fluctuate with downward movement of wetting fronts and are negatively correlated with pH. Concentrations
of Fe in soil solution are about 10 times greater than those of throughfall and stemflow; the corresponding relative differences
for Cu and Zn were much less. Plant uptake of Mn exceeds that of Cu, Zn, and Fe. The increases in Mn concentrations from precipitation
to throughfall and stemflow are much greater than those for Cu, Zn, and Fe because precipitation has very low Mn concentrations.
The concentration series for Mn is: precipitation<soil solutions<throughfall<stemflow. Concentrations of Mn in the soil solution
are negatively correlated with pH. During the dry summer Mn accumulates in the soil, but is quickly flushed by early rains
of the wet season.
... Precipitation pHs in the studied plantation ranged from 3.54 to 4.52 (Table I), a common situation in northern central Venezuela as a consequence of high industrial (petrochemical and fertilizer production plants) and agricultural (crop fertilization and cattle raising) activities (Lewis and Weibezahn;1981, Sequera et al., 1991López-Hernández et al., 2012). In the rest of Venezuela, even in the absence of anthropogenic influence, precipitation is fairly acid (5.1-5.8) ...
... The weighted average Zn concentration in precipitation (40.1 µg L -1 ) was higher in the sugar cane agroecosystem than the values presented in tropical environments by Steinhardt and Fassbender (1979) in a cloud forest (2.4 µg L -1 ), López-Hernández (2008) in a seasonally flooded Venezuelan savanna (28.6 µg L -1 ), and McColl (1981) in a temperate eucalypt forest (16.1 µg L -1 ), but lower than Zn concentration reported by Golley et al. (1975) in a Panamanian rain tropical forest (44 µg L -1 ), and by Liu et al. (2005) in the southern Yellow sea, China (60-150 µg L -1 ). In pristine environments, the weighted average Zn concentration in precipitation greatly surpasses the Cu concentrations (Driscoll et al., 1994;Liu et al., 2005;Muezzinoglu and Cukurluoglu, 2006). ...
... Precipitation pHs in the studied plantation ranged from 3.54 to 4.52 (Table I), a common situation in northern central Venezuela as a consequence of high industrial (petrochemical and fertilizer production plants) and agricultural (crop fertilization and cattle raising) activities (Lewis and Weibezahn;1981, Sequera et al., 1991López-Hernández et al., 2012). In the rest of Venezuela, even in the absence of anthropogenic influence, precipitation is fairly acid (5.1-5.8) ...
... The weighted average Zn concentration in precipitation (40.1 µg L -1 ) was higher in the sugar cane agroecosystem than the values presented in tropical environments by Steinhardt and Fassbender (1979) in a cloud forest (2.4 µg L -1 ), López-Hernández (2008) in a seasonally flooded Venezuelan savanna (28.6 µg L -1 ), and McColl (1981) in a temperate eucalypt forest (16.1 µg L -1 ), but lower than Zn concentration reported by Golley et al. (1975) in a Panamanian rain tropical forest (44 µg L -1 ), and by Liu et al. (2005) in the southern Yellow sea, China (60-150 µg L -1 ). In pristine environments, the weighted average Zn concentration in precipitation greatly surpasses the Cu concentrations (Driscoll et al., 1994;Liu et al., 2005;Muezzinoglu and Cukurluoglu, 2006). ...
As a consequence of high industrial and agricultural activities, acidic rains loaded with pollutantsincluding nutrientsare characteristic of northern central Venezuela, a region dominated by sugar cane plantations. Canopies of forest and agricultural crops can modify the chemistry of rainfall through uptake, leaching and outwash of deposited ions. This paper describes the change in the chemistry of acid rains after passing through a sugar cane canopy. Four plots of 300 m2 within a 4.5 ha experimental area, planted with Saccharum officinarum had rain and throughfall collectors installed. The study corresponds to the analysis of the growing season of the third ratoon. The pH of the rain in the agroecosystem increased after passing through the canopy. The magnitudes of the changes were important and partially related to the significant amount of cations leached from the leaves or washed out from dry deposition to the leaves. N inputs for wet and dry deposition in the agroecosystem were high (25.25 kg ha-1 yr-1) as a consequence of the agricultural activity in the area, the local burning of sugar cane before cropping, and the location of the experimental area close to petrochemical and fertilizer industries. Rainfall constitutes an important source of nutrient inputs to the sugar cane system. In the case of macronutrients (N, P and K) the inputs were high and supply an important fraction of plant nutrient needs, as occurs for zinc and copper.
... The flux of metals to the forest floor differs from the sum of wet and dry precipitation, showing the effects of interactions between the precipitation and leaf surfaces (Lindberg and Harriss 1981, McColl and Bush 1978, Heinrichs and Mayer 1980, McColl 1981. The enrichment in manganese is particularly high (see Table 27); for zinc and cadmium smaller enrichments are observed. ...
... However, in Mantecal precipitation water, weighted average Zn concentration only surpassed about three times Cu rain water concentration. The weighted average Zn concentration in precipitation in MEM (28.6 μg l −1 ) is higher than the values presented by Steinhardt and Fassbender [21] in a rain forest located in San Eusebio, Venezuela (2.4 μg l −1 ), and by McColl [22] in a eucalypt forest (16.1 μg l −1 ), but is lower than information reported by Golley et al. [23] in a Panamanian rain tropical forest (44 μg l −1 ), and by Liu et al. [19] in the Southern Yellow Sea, China (60-150 μg l −1 ). Cu concentration in rain water of MEM (about 12.1 μg l −1 ) is higher than the values presented by Steinhardt and Fassbender [21] in San Eusebio, Venezuela (2.79 μg l −1 ) and lower than the value presented by Golley et al. [23] for the Panamanian forest ecosystem (24.0 μg l −1 ) and by Muezzinoglu and Cukurluoglu [20] in Izmir, Turkey (19.7 μg l −1 ), and about the same as values presented by Liu et al. [19] in the coastal region of the Southern Yellow Sea, China (3-15 μg l −1 ). ...
There is very little information on the cycling of heavy metals in natural savannas. Venezuelan flooded savannas are characterised by acid soils with redox conditions which might induce Zn and Cu solubilisation. In those flooded savannas a network of small dykes has been constructed to control floods. The biomass accretion after dyking and the abundance of clay particles in the vertisols, dominant in the overflow plains, might be responsible for an increase in nutrient uptake and immobilisation. Due to the redox and pH conditions prevailing during flooding, some questions arise on the fate of the heavy metals. Are they significantly lost as soluble and particulate forms, which in turn, can induce a potential risk of microelement deficiency? Or, on the contrary, are heavy metal inputs in precipitation waters retained somewhere in the terrestrial pools of the watershed allowing for an adequate micronutrient economy? By using input-output budgets, which consider the total atmospheric input and total output in stream runoff (soluble and particulate) for zinc and copper we concluded that in Mantecal flooded savannas, a net accumulation of micronutrient in soils is actually occurring through organic and inorganic complexes, a process that is counterbalanced by the losses of particulates through erosion.
... However, in Mantecal precipitation water, weighted average Zn concentration only surpassed about three times Cu rain water concentration. The weighted average Zn concentration in precipitation in MEM (28.6 μg l −1 ) is higher than the values presented by Steinhardt and Fassbender [21] in a rain forest located in San Eusebio, Venezuela (2.4 μg l −1 ), and by McColl [22] in a eucalypt forest (16.1 μg l −1 ), but is lower than information reported by Golley et al. [23] in a Panamanian rain tropical forest (44 μg l −1 ), and by Liu et al. [19] in the Southern Yellow Sea, China (60-150 μg l −1 ). Cu concentration in rain water of MEM (about 12.1 μg l −1 ) is higher than the values presented by Steinhardt and Fassbender [21] in San Eusebio, Venezuela (2.79 μg l −1 ) and lower than the value presented by Golley et al. [23] for the Panamanian forest ecosystem (24.0 μg l −1 ) and by Muezzinoglu and Cukurluoglu [20] in Izmir, Turkey (19.7 μg l −1 ), and about the same as values presented by Liu et al. [19] in the coastal region of the Southern Yellow Sea, China (3-15 μg l −1 ). ...
There is very little information on the cycling of heavy metals in natural savannas. Venezuelan flooded savannas are characterised by acid soils with redox conditions which might induce Zn and Cu solubilisation. In those flooded savannas a network of small dykes has been constructed to control floods. The biomass accretion after dyking and the abundance of clay particles in the vertisols, dominant in the overflow plains, might be responsible for an increase in nutrient uptake and immobilisation. Due to the redox and pH conditions prevailing during flooding, some questions arise on the fate of the heavy metals. Are they significantly lost as soluble and particulate forms, which in turn, can induce a potential risk of microelement deficiency? Or, on the contrary, are heavy metal inputs in precipitation waters retained somewhere in the terrestrial pools of the watershed allowing for an adequate micronutrient economy? By using input-output budgets, which consider the total atmospheric input and total output in stream runoff (soluble and particulate) for zinc and copper we concluded that in Mantecal flooded savannas, a net accumulation of micronutrient in soils is actually occurring through organic and inorganic complexes, a process that is counterbalanced by the losses of particulates through erosion.
... The average manganese concentrations in the twigs of the sampled trees agree with reported values in the literature. McColl [32] observed average manganese concentrations of 250 mg kg 1 in the twigs of blue gum eucalyptus trees. Brotherson and Osayande [33] observed average manganese concentrations of 12.0 and 13.1 mg kg 1 in the twigs of mountain mahogany and Utah juniper trees. ...
A surface flow constructed wetland was used to treat stormwater runoff from surrounding watersheds which are comprised primarily of commercial properties and two former landfills. The uptake of manganese by red maple, white birch and red spruce trees growing under flooded soil conditions in the constructed wetland was compared to that of the same trees growing under well drained soil conditions in a nearby reference site. The seasonal variability of manganese and its distribution in different compartments of these trees (leaves, twigs, branches, trunk wood, trunk bark and roots) were studied. The average manganese concentrations in the aboveground compartments of red maple, white birch and red spruce trees were within the range of manganese concentrations reported in the literature for these trees. The concentrations of manganese in the aboveground compartments of red maple, white birch and red spruce trees in the reference site were significantly greater than those in the constructed wetland (with the exception of manganese concentrations in the trunk wood of red maple trees) because of the acidic soil conditions of the reference site. The percent distribution of manganese in the aboveground compartments of trees did not vary during the growing season. Higher concentrations of manganese were present in the trunk bark and either the leaves or twigs of species on both the constructedwetland and the reference site regardless of the sampling date.
... Pastor and Bockheim [37] observed average iron concentrations of 93 and 52 mg kg 1 in the twigs of sugar maple and trembling aspen trees. McColl [38] observed average iron concentrations of 45 mg kg 1 in the twigs of blue gum eucalyptus trees. Brotherson and Osayande [39] observed average iron concentrations of 166.4 and 146.2 mg kg 1 in the twigs of mountain mahogany and Utah juniper trees. ...
A surface flow wetland was constructed in the Burnside Industrial Park, Dartmouth, NovaScotia, to treat stormwater runoff from the surrounding watersheds which are comprised primarily ofcommercial properties and two former landfills. The objectives of this study were: (a) to compare theuptake of iron by red maple, white birch and red spruce trees growing under flooded soil conditions inthe constructed wetland and well drained soil conditions in a nearby reference site, (b) to evaluate theseasonal variability of iron in these trees and (c) to determine the distribution of iron in differentcompartments of these trees (leaves, twigs, branches, trunk wood, trunk bark and roots). The averageiron concentrations in the aboveground compartments of red maple, white birch and red spruce treeswere within the range of iron concentrations reported in the literature for these trees. Red maple, whitebirch and red spruce trees in the constructed wetland had significantly greater iron concentrations intheir roots than the same species in the reference site. The average iron concentrations in the leaves ofred maple trees in the constructed wetland and the reference site displayed an increasing trend towardsthe end of the growing season while the average iron concentrations in the twigs of red maple andwhite birch trees in the constructed wetland and the reference site displayed maximum concentrationsat the beginning of the growing season. Red maple, white birch and red spruce trees in the constructedwetland retained a major portion of their overall iron concentration in their root systems.
This contribution represents the effort of our research for more than fifty years. The first chapters deal with the general characteristics of the savannah, including the role that fire plays in the management of this biome and in the processes involved in the cycles of nitrogen and phosphorus, key elements in the productivity of tropical savannahs. Particular emphasis is placed on the work on flooded savannahs and in the modulation experiment (building of dikes) for flood control and water resource management. In addition, the modulation scheme is used for the calculation of the nutritional balances of biogeochemical elements with sedimentary cycles, a piece of completely original information in savannah ecosystems.
We reviewed the effects of physical and chemical characteristics of filter materials on trace metal concentrations in soil solutions to evaluate their suitability for porous sections of suction cups. Among the materials described in the literature, e.g. ceramics, Al2O3, sintered Ni or glass, and various plastic filters, a great variation in bubbling pressure, pore size, permeability, chemical composition and stability, CEC, and trace metal dissolution/precipitation or adsorption/desorption processes was found. A low adsorption capacity suggests plastic materials are suitable, provided the bubbling pressure is high enough. All other materials have disadvantages in one or more properties, e.g. release of trace metal impurities into the soil solution, clogging of pores by precipitation of previously dissolved compounds, or sorption of trace metals.
Many reported experiments on sorption of trace metals by various materials are not relevant because of the unrealistic high metal concentrations of the test solutions. Our experiments with realistic concentrations revealed that sorption processes during the extraction may alter trace metal concentrations in soil solutions significantly.
Ceramic or Al2O3 cups are commonly used, but they adsorb appreciable amounts of trace metals. Therefore, we conclude that metal fluxes and budgets based on such data have to be interpreted with caution. To improve data comparability, detailed description of suction cup materials in the method sections of papers would be required. Moreover, more development and testing with plastic materials should be done, aimed at the optimization of both physical and chemical properties.
The physical and chemical development of three Holocene-aged Spodosols, found in the north-eastern United States on differing parent materials, was analyzed using mass-balance modeling in conjunction with complementary micromorphological and chemical techniques. The accumulation of soil organic matter, in combination with the process of past root growth, resulted in profile volumetric expansions of up to 86%. In all soils, expansion was greatest in Bhs horizons. Extensive mineral weathering and profile losses of Mg, Ca, Na, K, and Si occurred (102–105 kg ha−1), concurrent with organic matter accumulations. Total cation losses were generally comparable to those measured in similar Holocene-aged soils, although losses varied somewhat between soils depending on the primary minerals present and their relative stabilities. Profile losses were also calculated for Fe, Al, and Mn and are comparable to those calculated in other regional studies; however, one soil clearly showed a net enrichment of Fe, presumably from external (i.e., atmospheric) sources. Other soils could be receiving such atmospheric additions as well. In all soils, Fe, Al, and Mn displayed zones of net pedogenic accumulation (in B and C horizons) below zones of net depletion (from overlying E and upper B horizons). From the standpoint of terrestrial C budgets, more carbon dioxide is apparently “consumed” by these soils through long-term organic C build-up (11–29 kg C ha−1 yr−1) than is lost through long-term mineral weathering and inorganic C (bicarbonate) leaching (3–13 kg C ha−1 yr−1).
In Buchenbeständen des nordöstlichen Wienerwaldes auf Pseudogleystandorten wurde die Anreicherung und das Verhalten von Schwermetallen im Einsickerungsbereich von stark saurem, schadstoffangereichertem Stammablaufwasser untersucht. Analysen von Bodenbohrkernserien mit zunehmenden Abständen vom Stammanlauf brachten folgende Ergebnisse:
+ Im Einsickerungsbereich des Stammablaufwassers waren die pH‐Werte teilweise bis auf weniger als pH3 abgesunken. In stammferneren Bereichen lagen sie um bis zu mehr als 2 pH‐Einheiten darüber.
+ Die Anreicherung von Blei erreichte in Stammnähe Werte von 500 bis mehr als 1200 mg·kg ⁻¹ Feinboden; die von Kupfer 70 bis 150 mg·kg ⁻¹ und die von Zink 250 bis 500 mg·kg ⁻¹ .
+ Mangan wurde in diesem Bereich verstärkt ausgewaschen.
+ In Stammnähe waren die Anteile an komplexierbarem Blei und Kupfer im Oberboden geringer und in tieferen Bodenschichten größer als in stammfernen Bereichen.
Foliage of each species was sampled at 26 paired locations in the San Francisco Bay area. Eucalyptus globulus had significantly higher concentrations of Mn, Ca and Na, but significantly lower concentrations of Cu, Fe, Zn, P, NO3‐N and Kjeldahl‐N than did Quercus agrifolia. Concentrations of K and Mg did not differ between species. The relative concentration series for the species were similar: N>Ca>K>Mg>Na>P>Mn>Fe for Q. agrifolia and Ca>N>K> Mg>Na>Mn>P>Fe for E. globulus. Correlations between species were statistically significant for concentrations of Fe and Ca only. Thus, for these elements analysis of one species could be used as an indicator of the other.
A study was carried out to determine the total accessions of Cd, Cu, Pb and Zn in bulk precipitation, throughfall, stemflow, and litterfall at a secondary forest in Kuala Lumpur, Malaysia. This study shows that the urban environment of Kuala Lumpur contributes a considerable amount of heavy metals to the atmosphere and forest floor as reflected by the high metal contents in bulk precipitation, throughfall and stemflow. The forest canopy filters and retains the metals, which are subsequently transferred to the soil. The concentrations of the metals in precipitation, throughfall and litterfall were in the order ZnPb > Cu > Cd. As a result of interaction between the atmosphere and the forest canopy, the net fluxes of heavy metals to the forest floor were 156.4, 121.7, 28.2 and 10.4 g · ha−1 · week−1 for Zn, Pb, Cu and Cd, respectively. All the metals studied showed net retention at the canopy with Pb as the most retained metal followed by Zn, Cu and Cd. The aqueous pathways contributed more to the net flux of heavy metals (except for Zn) than litterfall.
The concentrations and annual fluxes of Fe, Al, Mn, Cu and Pb were measured during 1983 in bulk precipitation, throughfall, stem-flow, forest floor percolate, mineral soil solution below the root zone and streamflow in a maple-birch stand on an acid podzolic soil at the Turkey Lakes Watershed (TLW), Ontario. Inputs of metals to TLW in precipitation were small in comparison with those in the eastern United States and Europe. Considerable loss of Mn and Cu from the vegetation during both the growing and the dormant (leafless) periods was observed and presumed to be due to leaching. The enrichment in soil solution of all metals examined, in relation to throughfall, was greatest for Al (7X) and least for Cu (1.2X). Aluminum was mobilized in both the forest floor and the mineral soil, the latter possibly in association with SO4
2–. Copper was solubilized in the lower forest floor or the mineral soil. Surface soil contents of Al and Cu were reduced by Al and, to a lesser extent, Cu leaching beyond the effective rooting zone. Iron, Mn and Pb were mobilized largely in the F horizon of the forest floor, most likely by organic acids. Leaching of Fe, Mn and Pb was reduced by metal accumulation in vegetation, the lower forest floor, or mineral soil within the effective rooting zone of the vegetation. Most (80 to 99%) of the metals leached from the rooting zone were retained in the watershed and did, not appear in streamwater.
The literature on the fluxes of six heavy metals in temperate forest ecosystems is reviewed. Special attention is given to wet and dry deposition and internal flux, to metal budgets for ecosystems and soils, to concentrations in aqueous compartments of the ecosystem and to speciation in soil solutions. Metal fluxes are discussed in relation to pollution load, soil type, tree species and land use. The mobility of Cu and Pb is strongly dependent on the solubility of organic matter. These metals are commonly accumulated in forest soils. Zinc, Cd and Ni are greatly influenced by soil acidity and are often lost in considerable amounts from acidified soils. Chromium is often at balance in forest ecosystems. Implications for metal solubility and budgets in forest soils are discussed in connection with an increase in soil acidification.
Heavy metal pollution is one of the most troublesome environmental problems faced by mankind nowadays. Copper, in particular,
poses serious problems due to its widespread industrial and agricultural use.
Unlike other heavy metals, such as cadmium, lead, and mercury, copper is not readily bioaccumulated and thus its toxicity
to man and other mammals is relatively low. On the contrary, plants in general are very sensitive to Cu toxicity, displaying
metabolic disturbances and growth inhibition at Cu contents in the tissues only slightly higher than the normal levels.
The reduced mobility of Cu in soil and sediments, due to its strong binding to organic and inorganic colloids, constitutes,
in a way, a barrier to Cu toxicity in land plants. In aqueous media, however, plants are directly exposed to the harmful effects
of Cu and, thus, algae and some species of aquatic higher plants are more easily subjected to Cu toxicity.
Excess Cu inhibits a large number of enzymes and interferes with several aspects of plant biochemistry, including photosynthesis,
pigment synthesis, and membrane integrity. Perhaps its most important effect is associated with the blocking of photosynthetic
electron transport, leading to the production of radicals which start peroxidative chain reactions involving membrane lipids.
Copper effects on plant physiology are wide ranging, including interference with fatty acid and protein metabolism and inhibition
of respiration and nitrogen fixation processes. At the whole plant level Cu is an effective inhibitor of vegetative growth
and induces general symptoms of senescence.
The high toxicity of Cu to plants has led to the evolution of several strategies of defense. Among the most important ones
is the production of Cu-complexing compounds. Although the nature, structure, and function of these compounds is still controversial,
they can be divided into two main groups: metallothionein-like compounds and phytochelatins. The latter appears to constitute
the most widespread response of plants to stresses provoked by metals, including Cu.
La pollution par métaux lourds c’est un des plus sérieux problèmes environmentalles de l’actualité. Le cuivre pose des problèmes
très particuliers, en conséquence de sa vaste utilisation dans l’industrie et dans l’agriculture.
Au contraire d’autrex métaux, comme le cadmium, le plomb et le mércure, le cuivre n’est pas facilement accumulé par les organismes,
et sa toxicité pour l’homme et pour les autres mammifères est relativement réduite. Les plantes sont, généralement, plus sensibles
à la toxicité du Cu, par rapport aux animaux, et elles presentent des perturbations du métabolisme et inhibition du développement
a partir de niveaux de Cu dans les tissues légèrement supérieurs aux normaux.
La faible mobilité du Cu dans le sol et dans les sediments, en conséquence des fortes liaisons qu’il établit avec les coloïdes
organiques et inorganiques du sol, constitue, dans une certaine mesure, une barrière contre la toxicité du Cu, au moins dans
les plantes terrestres. Dans le milieu aquatique les plantes sont directement exposées aux effets nuisibles du Cu, donc les
algues et les plantes aquatiques en général sont très sensibles à ce metal.
L’excès de Cu inhibe un grand nombre d’enzymes et interfère avec plusieurs aspects de la biochimie végétale, nommément avec
la photosynthèse, la synthèse de pigments et l’integrité des membranes biologiques. Le plus important de ces effets c’est
peutêtre le blocage du transport photosynthétique d’électrons, conduisant à la production de radicaux qui constituent le premier
pas d’une chaîne de réactions peroxydatives des lipides des membranes.
Le Cu a une vaste gamme d’éffets sur la physiologie végétale, nommément l’interference avec le métabolisme des acides gras
et des protéines et l’inhibition de la respiration et des réactions de fixation d’azote. En considérant la plante comme un
tout, le Cu est un efficace inhibiteur du développement et induit des symptomes de sénescence.
La considérable toxicité du Cu pour les plantes les a emmené à l’évolution de plusieurs stratégies de défense. Une des plus
importantes c’est la production de substances qui compléxent le Cu en excès. La nature, structure et fonction de ces substances
sont object de controverse, mais deux groupes ont été identifiés: les substances de la famille des métallothioneines et les
phytochelatines. Apparement, les dernières sont produites par plusieurs espèces de plantes comme réponse à l’excès de métaux
(nommément Cu) dans l’environement.
Concentrations and quantities of S, Al, B, Cu, Fe, Mn, Ni, Pb, and Zn were determined in throughfall (TF) and stemflow (SF) samples collected from 1971 to 1981 in six softwood and three hardwood stands located at the Acadia Forest Experiment Station in central New Brunswick, Canada. Analyses were carried out using freeze-dried total solids in samples of TF, SF, and rainwater. The respective volume weighted average concentrations (for 1971–1981) of Al, B, Cu, Fe, Mn, Ni, Pb, and Zn in the bulk precipitation were 18, 3, 5, 18, 45, 0.56, 27, and 96 μgL−1. The volume weighted average concentration of S in rainwater for the 1971–1981 period was 1.30 mg L−1. In the TF of each species the concentrations of Mn and B were significantly higher than those in rainwater, whereas the reverse was true for the concentrations of Ni, PB, and Zn. There were significant differences among species in both concentrations and deposition rates of various elements. Fertilizer treatment of the stands had significant effects on the quantities of nutrients cycled as TF. The concentrations of various elements in the SF samples were consistently higher than those in the rainwater. The deposition rates of these, however, were comparatively less than those in TF. The quantities of elements cycled in SF differed significantly among species. The ratios of the quantities of nutrients cycled by TF and SF combined and those in the rainwater indicate that Zn is absorbed from rain by the tree canopies, and Mn, Cu, and B are released. The results suggest that the quantities of S and metals cycled in forest ecosystems are functions of tree species and of the nutritional status of tree species.
A study was carried out to determine the chemical composition of bulk precipitation, throughfall and stemflow in an urban forest in Kuala Lumpur, Malaysia. The mean weekly rainfall recorded during the period of study was 63.2 mm. Throughfall, stemflow and canopy interception of incident precipitation were 77.1%, 1.2% and 21.7% respectively. Bulk precipitation, througfall and stemflow were acidic, the pH recorded being 4.37, 4.71 and 4.15 respectively. In all cases the dominant ions were NO3, SO4, Cl, NH4, K, Ca and Na. Of the ions studied Ca, K, Cl, SO4, Mg and Mn showed net increases in passing through the forest canopy, while NH4, Na, NO3, Zn, H and Fe showed net retention. This study shows that the urban environment of Kuala Lumpur contributes considerable amounts of materials to the atmosphere, as reflected by the high ionic contents in bulk precipitation, throughfall and stemflow.
Northern New England is subject to deposition of remotely derived air borne pollutants. Mountain ecosystems of the region are particularly exposed because orographic precipitation and windy, cloudy conditions contribute to higher deposition rates. This study describes the concentrations and total quantities of Pb and Zn in organic horizons of soils distributed over an elevational gradient. Pb concentrations are high for a remote area, and comparable with many heavily travelled roadsides. Zn concentrations fell within a broad range of levels presumed to represent natural conditions. The vertical distribution of Pb suggests that levels are still rising; the elevational distribution suggests that deposition rates are highest in subalpine forests where there is a combination of high winds and ample interceptive plant surfaces. High elevation ecosystems may serve a valuable role as amplifying systems for the detection of certain pollutants, and as convenient systems for understanding the pattern of deposition and the ecological effects of pollutants.
It is proposed that the hydrous oxides of Mn and Fe, in general, furnish the principal control on the fixation of Co, Ni, Cu, and Zn (heavy metals) in soils and fresh water sediments; hydrous oxides of Mn and Fe are nearly ubiquitous in clays, soils, and sediments. The common occurrence of these oxides as coatings allows the oxides to exert chemical activity far out of proportion to their total concentrations. Sorption or desorption of these heavy metals occurs in response to the following factors: (1) aqueous concentration of the metal in question; (2) aqueous concentration of other heavy metals; (3) pH; and (4) amount and strength of organic chelates and inorganic complex ion formers present in solution. Other suggested controls on the concentration of the heavy metals in soils and fresh waters are: (1) organic matter; (2) clays; (3) carbonates; and (4) precipitation as the discrete oxide or hydroxide. The available information on these controls is reviewed and found to be inadequate to explain the fixation of Co, Ni, Cu, and Zn.
Soil solutions were sampled with porous‐cup suction devices during a rainy season (December 1974–May 1975) from adjoining uncut and clearcut Eucalyptus globulus forest areas in the Berkeley hills, California. Concentrations of K ⁺ , Ca ²⁺ , Mg ²⁺ , NO 3 ‐ , HCO 3 ‐ , and pH and specific conductance were lower in the clearcut. The high exchange capacity of the clay‐loam soil, the limited amount and duration of rainfall, and the removal of slash and litter from the clearcut were factors contributing to these results which differ from those of similar studies of the effects of clearcutting elsewhere.
The relative proportions of Na ⁺ , Cl ‐ , and SO 4 2‐ were higher, and those of K ⁺ , Ca ²⁺ , NO 3 ‐ , and HCO 3 ‐ were lower in the clearcut compared to the forest; the proportions of Mg ²⁺ were the same. The relative ionic composition of soil solutions in the clearcut resembled that of the acid rain (pH 5.0). The higher proportion of HCO 3 ‐ in the forest was due to throughfall inputs, root respiration, and decomposition of the forest floor. No NH 4 ⁺ was detected in soil solutions from either area.
Concentrations of most ions were correlated between and within soil horizons, although K ⁺ was an exception due to clay fixation. During anaerobic conditions, Mn and Fe and associated Cu and Zn were mobilized in the soil solution.
Increased quantity of soil water following clearcutting resulted in increases in total amounts of most ions in solutions in the lower portion of the profile in the clearcut, compared to the uncut forest.
Soil solutions were sampled with porus-cut suction devices during a rainy season (December 1974-May 1975) from adjoining uncut and clearcut eucalyptus globulus forest areas in the Berkely Hills, California. Concentrations of K/sup +/, Ca/sup 2 +/, Mg/sup 2 +/, NO/sup 3 -/, HCOââ», and pH and specific conductance were lower in the clearcut. The high exchange capacity of the clay-loam soil, the limited amount and duration of rainfall, and the removal of slash and litter from the clearcut were factors contributing to these results which differ from those of similar studies of the effects of clearcutting elsewhere. The relative proportions of Na/sup +/, Clâ», and SOââ»Â² were higher, and those of K/sup +/, Ca/sup +2/, NOââ», and HCOââ» were lower in the clearcut compared to the forest; the proportions of Mg/sup 2 +/ were the same. The relative ionic composition of soil solutions in the clearcut resembled that of the acid rain (pH 5.0). The higher proportion of HCOââ» in the forest was due to throughfall inputs, root respiration, and decomposition of the forest floor. No NHâ/sup +/ was detected in soil solutions from either area. Concentrations of most ions were correlated between and within soil horizons, although K/sup +/ was an exception due to clay fixation. During anaerobic conditions, Mn and Fe and associated Cu and Zn were mobilized in the soil solution. Increased quantity of soil water following clearcutting resulted in increases in total amounts of most ions in solutions in the lower portion of the profile in the clearcut, compared to the uncut forest.
Eucalyptus globulus (Labill.) forests in the Oakland‐Berkeley hills, California, were clearcut in 1973–74 following severe damage from freezing in December 1972. The soil water regimes in clearcut and adjoining uncut areas, were compared during the two years following cutting.
During the wet winter season (Dec.–May), surface drying and evapotranspiration by annual grasses were the only losses in the clearcut; more soil water was retained in the clearcut due to lack of evapotranspiration by the forest trees.
Soil water rapidly decreased in both the clearcut and forest during the long, dry summer periods, and differences between the two areas widened. By midsummer soil matric suctions in the clearcut dropped below 15 bars (22.4% P v , volumetric water content), and in the forest to below 70 bars (8.5% P v ). During the summer, P v increased with profile depth in the clearcut, but in the forest, soil water was depleted uniformly with depth in the profile.
Although volumetric water contents of soil ( P v ) were significantly different between clearcut and forest areas, rates of water loss ( k ) during summer were not clearly related to forest cover. In the clay‐loam soil, k was dependent on the soil water storage at the beginning of the dry summer period, on the ability of trees in the uncut forest to withdraw water from parent material and from fractured bedrock in excess of that available in the soil profile, and on P v which decreased during summer.
The ceramic cups of soil moisture access tubes were found to contribute excessive amounts of Ca, Na and K to solutions drawn through them. They also adsorbed significant amounts of P from solutions containing P.
Leaching the cups with 1 N HCl reduced the contamination of Na and K to acceptable levels. Calcium levels were greatly reduced but significant amounts of Ca contamination continued. Phosphorus adsorption was reduced to an acceptable level.
Concentrations and annual fluxes of K, Na, Ca, Mg, Al, Fe, Mn, Zn, N, S, P, Cr, Cu, Ni, Pb, Sb, Bi, Cd, Hg, and Tl were measured in the precipitation input to the forest canopy, in precipitation beneath canopy, and in the seepage water below the humus layer and below the tree root zone (output) both in a Central European beech ( Fagus silvatica ) and in a spruce ( Picea abies ) forest. Concentrations were determined in an acid loess loam soil from the beech site and in a calcareous little‐weathered loess C‐horizon for the same elements plus Sr and V.
When precipitation was passing through the forest canopy, some elements were partially retained (P, Cu, Fe, Zn, Hg, Cr). The flux of other elements increased during canopy passage.
Strong retention of Pb and Ni in the organic surface layer (O‐horizon) was found when seepage water passed through it. Within the mineral soil, retention of dissolved elements from the seepage water is observed in the case of K, Ca, Fe, N, S, P, Cr, Pb, Sb, Hg, and Tl.
Compared to the unweathered loess, the acid forest soil was nearly depleted of its Ca and carbonate‐C contents. A similar, but less distinct, decrease was found in the total profile (Na, Sr, V, Cr, Cu, Zn), or in the soil surface layer only (Mg, Al, Fe, Mn, Ni, Co). Carbon, N, P, S, Pb, Hg, Bi, and Tl accumulated in the soil surface layer.
The input/output balance showed that both forest ecosystems accumulated all elements entering the system with atmospheric precipitation except Al and Mn. The elements Pb, Hg, Bi, and Tl accumulated mainly within the top soil.
Metal distribution in vegetation and soil components, annual inputs, and losses were determined in undisturbed urban and rural ecosystems in northwestern Indiana. The urban area has been exposed to contamination from industrial and other urban sources for about 100 years. The levels of cadmium, zinc, copper, and lead (Cd, Zn, Cu, and Pb) were significantly higher in the soils and vegetation on the urban site compared to a similar system in a rural setting 67 km away. Metal concentration in the top 2.5 cm of soil averaged 10 ppm Cd, 2,456 ppm Zn, 463 ppm Pb, and 119 ppm Cu. This was 20 to 100 times more concentrated than that found on the rural site. The surface litter (O horizon) on the urban site also had four to nine times greater metal concentration and total metal quantities were many times greater in the urban ecosystem than on the rural site. The higher soil levels were reflected in higher concentrations in most plant species, but species differed greatly in metal levels.
Greater than 95% of the weight of all four metals was found in the soil (0–25 cm) for both dune and wetland ecosystems. The remaining metal burden is equally distributed between the surface litter and the plant biomass.
Slightly more Cd and twice as much Zn entered the urban site than the rural site during 1975–76. Annual input of Pb and Cu was four times greater on the urban site. While pollution control has apparently reduced annual input to the urban site, metal concentrations will remain high due to the low rates of leaching losses measured.
Laboratory and field tests were made to determine if porous ceramic cups collect representative samples of nitrate and phosphate from soil water. Substantial bias and variability were found. Some of the sources of sample bias were sorption, leaching, diffusion, and screening of phosphate ions by the cup walls. Sample variability of nitrate ions was strongly influenced by sampler intake rate, plugging, sampler depth, and type of vacuum system (which simulated different sampler sizes). These factors affect timing of sample collection and, because nutrient concentration in soil water is continually changing, they in turn affect sample concentration. These factors produced as much as a 60% range in sample concentration from eight samplers installed in a small uniform plot. Added to this variability is an unknown amount of bias representing the difference between the sample concentration and the average drainable soil‐water concentration. The many factors affecting the sample concentration together with the demonstrated variability and unknown bias make interpretation of sampler data difficult. To reduce sample variability, group samplers by intake rate, and use short sampling intervals, uniform sampler lengths, and the same initial vacuum for all samplers.
At Berkeley, California, main ionic constituents of bulk precipitation during the wet season of 1974-1975 were SOâ/sup 2 -/, Clâ», HCOââ», Na/sup +/, and Ca/sup 2 +/, and mean H/sup +/ concentration was 10.7 +/- 1.5 ..mu..eq/liter (pH 5.0). Although SOâ/sup 2 +/ comprised 50% of the anions in bulk precipitation, H/sup +/ concentration had the highest correlation with NOââ». Impacted air pollutants accumulated on tree leaves between major rainstorms. Atmospheric N and S were correlated with NOââ» and SOâ/sup 2 -/ in bulk precipitation and leafwash in a Eucalyptus globulus forest. Ionic composition of bulk precipitation resembled that of surface-soil solution in an adjoining, recently clear-cut area.
The critical links between anthropogenic emissions to the atmosphere and their effects on ecosystems are the mechanisms and rates of atmospheric deposition. The atmospheric input of several trace elements and sulfate to a deciduous forest canopy is quantified and the major mechanisms of deposition are determined. The study area was Walker Branch Watershed (WBW) in eastern Tennessee. The presence of a significant quantity of fly ash and dispersed soil particles on upward-facing leaf and flat surfaces suggested sedimentation to be a major mechanism of dry deposition to upper canopy elements. The agreement for deposition rates measured to inert, flat surfaces and to leaves was good for Cd, SO/sub 4//sup =/, Zn, and Mn but poor for Pb. The precipitation concentrations of H/sup +/, Pb, Mn, and SO/sub 4//sup =/ reached maximum values during the summer months. About 90% of the wet deposition of Pb and SO/sub 4//sup =/ was attributed to scavenging by in-cloud processes while for Cd and Mn, removal by in-cloud scavenging accounted for 60 to 70% of the deposition. The interception of incoming rain by the forest canopy resulted in a net increase in the concentrations of Cd, Mn, Pb, Zn, and SO/sub 4//sup =/ but a net decrease in the concentration of H/sup +/. The source of these elements in the forest canopy was primarily dry deposited aerosols for Pb, primarily internal plant leaching for Mn, Cd, and Zn, and an approximately equal combination of the two for SO/sub 4//sup =/. Significant fractions of the total annual elemental flux to the forest floor in a representative chestnut oak stand were attributable to external sources for Pb (99%), Zn (44%), Cd (42%), SO/sub 4//sup =/ (39%), and Mn (14%), the remainder being related to internal element cycling mechanisms. On an annual scale the dry deposition process constituted a significant fraction of the total atmospheric input. (ERB)
The elemental composition and relative contribution to input of precipitation and aerosols have been determined for the Walker Branch Watershed in Oak Ridge, Tennessee, U.S.A. Comparison of elemental ratios in rain to those in local soils indicates that Cu, Hg, and Pb are enriched with respect to soil by a factor of 30 to 170 and must have a non-soil source. Due to inherent problems encountered in determining elemental deposition velocities, elemental input by dry deposition was calculated using literature value upper and lower limits. If the higher deposition velocities are chosen, dry deposition could constitute from 62 to 96% of the total input for selected elements to the watershed.
Enrichment factor and chemical mass balance calculations have been applied to aerosol data in an attempt to distinguish between atmospheric particulates derived from soil, automobiles, and three nearby coal-fired steam plants. Elemental deposition by wet and dry fallout has also been calculated using published deposition velocities. Mass balance calculations indicate that no more than 5% of the total aerosol load can be attributed to the three coal-fired steam plants. The steam plants can, however, account for up to 20% of individual elements collected in air above the watershed.
As part of regional surveys of lakes in Norway the concentrations of Zn, Pb, Cu and Cd were measured in surface- and bottom-water samples collected from representative, small, pristine lakes (136 in southern Norway sampled in October 1974, 58 resampled in March 1975, and 77 in northern Norway sampled in March 1975). The lakes, a statistically representative sample of small lakes in Norway, were chosen such that their watersheds are undisturbed. Heavy-metal concentrations in these lakes thus reflect only natural inputs and anthropogenic inputs via the atmosphere.The generally low concentrations (Zn 0.5–12.0 μg l−1; Pb 0–2.0 μg l−1; Cu 0–2.0 μg l−1; Cd 0.1-0.5 μg l−1) measured in lakes in central and northern Norway provide estimates of natural “background” levels. These estimates may be too high because they include the global-scale deposition of heavy metals from the atmosphere which has increased as a result of industrial activities.Concentrations of Zn and Pb in lakes in southernmost and southeastern Norway lie above these “background” levels, apparently because of atmospheric deposition associated with the acidic precipitation that falls over southern Scandinavia. Increased heavy-metal concentrations in acid lakes may also be due to increased mobilization of metals due to acidification of soil- and surface-waters.
Thesis--Florida State University. Includes bibliographical references (leaves 480-512).
Microelement nutrition of forest trees: a review In Forest Fertilization: Theory and Practice. Tennessee Valley Authority, Muscle Shoals, Alabama, pp 132-175. 19 USDA 1974 Soil survey of Contra Costa County, California (an interim, unedited report) Soil Conservation Service
- Res Rep
- E L Stone
Res. Rep. 13178, Norway 28 p. 18 Stone, E. L. 1968 Microelement nutrition of forest trees: a review. In Forest Fertilization: Theory and Practice. Tennessee Valley Authority, Muscle Shoals, Alabama, pp 132-175. 19 USDA 1974 Soil survey of Contra Costa County, California (an interim, unedited report). Soil Conservation Service, USDA and Univ. Calif. Agric. Exp. Stn. 488 p.
A survey of acid precipitation in northern California. Final report to California Air Resources Board
- J G Mccoll
- J. G. McColl
Six trace elements in soils
- G W Leeper
- G. W. Leeper