PCDD/F and PCB in spruce forests of the Alps

PCDD/F and PCB concentrations in remote mountainous spruce stands of the Central European Alps show strong geographic variation. Independent of the matrix (0.5 year old needles, humus or mineral soil), the highest pollutant levels were always found at the lateral zones of the mountain range. High levels coincided with strong precipitation, particularly along the northern margin of the study region. The most volatile PCB congener propagated farther into the colder, drier central Alps than the heavier species. Matrices with different accumulation history (needles and humus) repeatedly reflected different spatial immission patterns. Consistent with its much longer exposure, pollutant levels in humus exceeded those of needles by up to two orders of magnitude. Needle contamination varied with altitude but the vertical trends were highly variable between transsects and changed between years, too.     

Analyses of enzyme activities and other metabolic criteria after five years of fumigation

Enzymatic activity (peroxidase, glutamate dehydrogenase, glutamine synthetase), foliage buffering capacity, soluble protein and nitrogen content were measured in current and previous year needles from young spruce (Picea abies) and fir (Abies alba). The trees were exposed to low levels of SO(2) and/or O(3) and simulated acidic precipitation (pH 4.0) in open-top chambers from 1983 through 1988. Needle samples were taken during March 1988 at the end of the five-year fumigation period. Exposure to SO(2) substantially increased sulphur content in both needle age classes of spruce and fir, and concomitantly reduced the foliage buffering capacity index (BCI), whereas the combined fumigation with SO(2) and O(3) had no effect on BCI. Peroxidase activity was markedly higher in year-old needles compared to current-year needles. However, trees from the SO(2) and SO(2) + O(3) treatments exhibited statistically significant stimulated peroxidase activities. Similarly, changes in the activities of the nitrogen-metabolizing enzymes indicated an altered cellular function of the trees after the long-term pollution stress. Levels of activity of both glutamate dehydrogenase and glutamine synthetase were increased by exposure to SO(2), especially in spruce. Although glutamate dehydrogenase in spruce was affected by all treatments, such changes in activity were found in fir only with the SO(2) treatment. The highest activity of glutamine synthetase, however, occurred in the older needles of trees exposed to SO(2) + O(3). Total nitrogen concentration was either unaffected by the pollutant treatments or decreased in spruce compared to the controls. No statistically significant changes due to the fumigation were found in soluble protein concentrations. Results indicated that chronic exposure to air pollutants lead to alterations in metabolic processes in conifer needles, detectable either by changes in typical stress indicating values or by increases in ammonium assimilation capacity.     

Long-term exposure to enhanced UV-B radiation has no significant effects on growth or secondary compounds of outdoor-grown Scots pine and Norway spruce seedlings

The effects of long-term enhanced UV-B radiation on growth and secondary compounds of two conifer species were studied in an outdoor experiment. Scots pine (Pinus sylvestris) seedlings were exposed for two growing seasons and Norway spruce (Picea abies) seedlings for three growing seasons to supplemental UV-B radiation, corresponding to a 30% increase in ambient UV-B radiation. The experiment also included appropriate controls for ambient and increased UV-A radiation. Enhanced UV-B did not affect the growth of the conifer seedlings. In addition, neither the concentrations of terpenes and phenolics in the needles nor the concentrations of terpenes in the wood were affected. However, in the UV-A control treatment the concentrations of diterpenes in the wood of Scots pine decreased significantly compared to the ambient control. Apparently, a small increase in UV-B radiation has no significant effects on the secondary compounds and growth of Scots pine and Norway spruce seedlings.     

Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure

Trichloroacetic acid (TCA, CCl(3)COOH) has been associated with forest damage but the source of TCA to trees is poorly characterised. To investigate the routes and effects of TCA uptake in conifers, 120 Sitka spruce (Picea sitchensis (Bong.) Carr) saplings were exposed to control, 10 or 100 microg l(-1) solutions of TCA applied twice weekly to foliage only or soil only over two consecutive 5-month growing seasons. At the end of each growing season similar elevated TCA concentrations (approximate range 200-300 ng g(-1) dwt) were detected in both foliage and soil-dosed saplings exposed to 100 microg l(-1) TCA solutions showing that TCA uptake can occur from both exposure routes. Higher TCA concentrations in branchwood of foliage-dosed saplings suggest that atmospheric TCA in solution is taken up indirectly into conifer needles via branch and stemwood. TCA concentrations in needles declined slowly by only 25-30% over 6 months of winter without dosing. No effect of TCA exposure on sapling growth was measured during the experiment. However at the end of the first growing season needles of saplings exposed to 10 or 100 microg l(-1) foliage-applied TCA showed significantly more visible damage, higher activities of some detoxifying enzymes, lower protein contents and poorer water control than needles of saplings dosed with the same TCA concentrations to the soil. At the end of each growing season the combined TCA storage in needles, stemwood, branchwood and soil of each sapling was <6% of TCA applied. Even with an estimated half-life of tens of days for within-sapling elimination of TCA during the growing season, this indicates that TCA is eliminated rapidly before uptake or accumulates in another compartment. Although TCA stored in sapling needles accounted for only a small proportion of TCA stored in the sapling/soil system it appears to significantly affect some measures of sapling health.     

Trichloroacetic acid in the environment

Suppositions that the trichloroacetic acid (TCA, CCl3C(O)OH) found in nature was a consequence solely of the use of chlorinated hydrocarbon solvents prompted this critical review of the literature on its environmental fluxes and occurrences. TCA is widely distributed in forest soils (where it was rarely used as an herbicide) and measurements suggest a soil flux of 160 000 tonnes yr(-1) in European forests alone. TCA is also produced during oxidative water treatment and the global flux could amount to 55 000 tonnes yr(-1) (from pulp and paper manufacture, potable water and cooling water treatments). By contrast, the yields of TCA from chlorinated hydrocarbon solvents are small: from tetrachloroethene 13 600 tonnes yr(-1) and from 1,1,1-trichloroethane 4300 tonnes yr(-1) on a global basis, at the atmospheric burdens and removal rates typical of the late 1990s. TCA is ubiquitous in rainwater and snow. Its concentrations are highly variable and the variations cannot be connected with location or date. However, there is no significant difference between the concentrations found in Chile and in eastern Canada (by the same analysts), or between Malawi and western Canada, or between Antarctica and Switzerland, nor any significant difference globally between the concentrations in cloud, rain and snow (although local enhancement in fog water has been shown). TCA is present in old ice and firn. At the deepest levels, the firn was deposited early in the 19th century, well before the possibility of contamination by industrial production of reactive chlorine, implying a non-industrial background. This proposition is supported by plume measurements from pulp mills in Finland. TCA is ubiquitous in soils; concentrations are very variable but there are some indications that soils under coniferous trees contain higher amounts. The concentrations of TCA found in plant tissue are region-specific and may also be plant-specific, to the extent that conifers seem to contain more than other species. TCA is removed from the environment naturally. There is abundant evidence that soil microorganisms dehalogenate TCA and it is lost from within spruce needles with a half-life of 10 days. There is also recent evidence of an abiotic aqueous decarboxylation mechanism with a half-life of 22 days. The supposedly widespread effects of TCA in conifer needles are not shown in controlled experiments. At concentrations in the needles of Scots pine similar to those observed in needles in forest trees, changes consequent on TCA treatment of field laboratory specimens were almost all insignificant.     

Comparison of PCDD/PCDF levels in soil, grass, cow''s milk, human blood and spruce needles in an area of PCDD/PCDF contamination through emissions from a metal reclamation plant

When in the vicinity of a metal reclamation plant in Tyrol, Austria, increased PCDD/PCDF levels were found in soil and spruce needles, the extent of grass contamination as well as the PCDD/PCDF content in milk of cows fed with hay from this area was determined. The milk samples showed a significant increase in PCDD/PCDF levels compared to control samples. In a blood sample of a farmer a significant increase in PCDD/PCDF levels was found. Correlations in PCDD/PCDF levels between soil, spruce needles, grass, cow's milk and human blood will be presented.     

Simultaneous monitoring of PCDD/Fs and PCBs in contaminated air with semipermeable membrane devices and fresh spruce needles

The contaminated air with burning plastic floor and electronic scrap was monitored with semipermeable membrane devices (SPMDs) and fresh unpolluted spruce needles at the same time for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). It was found that there were more polychlorinated dibenzofurans (PCDFs) than polychlorinated dibenzo-p-dioxins (PCDDs) collected from contaminated air. The total amounts of PCBs were much higher than that of PCDD/Fs, but the contribution of them to the WHO-TEQ was less than that of PCDD/Fs. Triolein-containing SPMDs can absorb much more PCDD/Fs and PCBs than spruce needles when they were exposed in contaminated air simultaneously. The logarithm of the concentrations of PCDD/Fs and PCBs in SPMDs and in spruce needles at the same sampling time exhibited a significant linear correlation, the correlation coefficients were larger than 0.86 for PCDD/Fs and 0.92 for PCBs. SPMDs and spruce needles are effective passive air sampler for PCDD/Fs and PCBs. SPMDs and spruce needles can complement each other in passive air sampling.     

Influence of foliar morphology and crown geometry on insecticide deposition and dissipation following an aerial spray over a mixed forest

Abstract

Deposition and dissipation of aerially sprayed phosphamidon insecticide over a mixed forest consisting of different species of coniferous and deciduous trees were studied. The data showed that the chemical deposited more and dissipated slower from deciduous foliage than from conifer needles. Differences in deposits and persistence were also found within each of the two foliar types. Leaf shape and orientation, crown geometry and foliar morphology appear to have played a role. No correlation was found between initial deposit levels and cuticular wax content of different foliar species. A controlled laboratory study showed that surface area/mass ratio played a more important role on initial deposits than pubescence/serrations present on foliar surfaces.     

Chemical and morphological characteristics of key tree species of the Carpathian Mountains

Concentrations of Al, B, Ca, Cu, Fe, K, Mg, Mn, N, Na, P, S and Zn in the foliage of white fir (Abies alba), Norway spruce (Picea abies) and common beech (Fagus sylvatica) from 25 sites of the Carpathian Mts. forests (Czech Republic, Poland, Romania, Slovakia and Ukraine) are discussed in a context of their limit values. S/N ratio was different from optimum in 90% of localities when compared with the European limit values. Likewise we found increase of Fe and Cu concentrations compared with their background levels in 100% of locations. Mn concentrations were increased in 76% of localities. Mn mobilization values indicate the disturbance of physiological balance leading to the change of the ratio with Fe. SEM-investigation of foliage waxes from 25 sites in the Carpathian Mts. showed, that there is a statistically significant difference in mean wax quality. Epistomatal waxes were damaged as indicated by increased development of net and amorphous waxes. The most damaged stomata in spruce needles were from Yablunitsa, Synevir and Brenna; in fir needles from Stoliky, and in beech leaves from Malá Fatra, Morské Oko and Beregomet. Spruce needles in the Carpathian Mts. had more damaged stomata than fir needles and beech leaves. Spruce seems to be the most sensitive tree species to environmental stresses including air pollution in forests of the Carpathian Mountains. Foliage surfaces of three forest tree species contained Al, Si, Ca, Fe, Mg, K, Cl, Mn, Na, Ni and Ti in all studied localities. Presence of nutrition elements (Ca, Fe, Mg, K and Mn) on foliage surface hinders opening and closing stomata and it is not physiologically usable for tree species.     

Are N and S deposition altering the mineral composition of Norway spruce and Scots pine needles in Finland?

Data from a large-scale foliar survey were used to calculate the extent to which N and S deposition determined the mineral composition of Scots pine and Norway spruce needles in Finland. Foliar data were available from 367 needle samples collected on 36 plots sampled almost annually between 1987 and 2000. A literature study of controlled experiments revealed that acidifying deposition mediates increasing N and S concentrations, and decreasing Mg:N and Ca:Al ratios in the needles. When this fingerprint for N and S elevated deposition on tree foliage was observed simultaneously with increased N and S inputs, it was considered sufficient evidence for assuming that acidifying deposition had altered the mineral composition of tree needles on that plot in the given year. Evidence for deposition-induced changes in the mineral composition of tree foliage was calculated on the basis of a simple frequency model. In the late eighties the evidence was found on 43% of the Norway spruce and 27% of Scots pine plots. The proportion of changed needle mineral composition decreased to below 8% for both species in the late nineties.     

Responses of spruce seedlings (Picea abies) to exhaust gas under laboratory conditions--II. Ultrastructural changes and stomatal behaviour

This study examines the effects of exhaust gas exposure on the epistomatal wax structure and mesophyll ultrastructure in needles of Norway spruce (Picea abies (L.) Karst.) seedlings. Stomatal diffusive resistance was also measured. Two independent exhaust gas fumigations were performed: 100 and 200 ppb measured as NO(x), for 10 days and 50, 100 and 200 ppb NO(x) for 19 days. The obstructive effect of exhaust gas exposure on epistomatal wax tubules was apparent. The stomata became covered by flat and solid wax resulting from the structural degradation of the wax crystalloids. Increasing the exhaust gas concentration in the chamber atmosphere exacerbated the degradation of the wax structure. Exhaust gas exposure induced aggregation and electron translucence of plastoglobuli, swelling of thylakoids, increase of cytoplasmic lipids and slight increase of vesiculation of cytoplasm in mesophyll cells of current and previous year needles. These changes were exemplified in current year needles. Damage to the epicuticular waxes and mesophyll ultrastructure of spruce needles most likely reflects the NO(x) and volatile hydrocarbon fraction. The alterations in epicuticular waxes and mesophyll ultrastructure can be related to accelerated senescence of the youngest, photosynthetically active, needle generation. The exhaust gas also resulted in decreased diffusive stomatal resistance at night which indicates that the exhaust gas exposure disturbed the gas exchange of spruce seedlings. The results show that even relatively short-term exposure to realistic concentrations of exhaust gas in the atmosphere can induce rather severe injuries to the needle surface structure as well as ultrastructure at the cellular level.     

Persistent effects of ozone on needle water loss and wettability in Norway spruce

Four-year-old, seed-grown trees of Norway spruce (Picea abies (L.) Karst.) were exposed in open-top chambers to charcoal-filtered air (8 h daily mean 54 microg O(3) m(-3)) over three consecutive summers (1986-1988). In mid-May 1988, before the third season of fumigation and more than 7 months after exposure to ozone the previous summer had terminated, daily rates of transpiration from intact shoots and water loss from excised needles were measured together with the amount of wax on the needle surface. In mid-July, 92 days after the beginning of the third year of exposure, the wettability of needles was assessed by measuring the contact angle of water droplets on the surface of needles. Exposure to 156 microg O(3) m(-3) resulted in a 16% increase in daily transpiration in current year's needles and a 28% increase in 1-year old needles. These effects were associated with slower stomatal closure in response to increasing water deficit in the needles previously exposed to 156 microg m(-3) ozone. The long-lasting nature of such ozone-induced effects could predispose trees to drought and winter desiccation. No significant effects of ozone were found on the amount of wax covering the needle surface, but a marked increase in the wettability of needles exposed to ozone was observed. The far reaching physiological consequences of these effects in the field and the possibility that similar disturbances may contribute to the decline of high-altitude forests of Norway spruce in Europe are discussed.     

Persistent stimulation of CO2 assimilation and stomatal conductance by summer ozone fumigation in Norway spruce

CO(2) assimilation rate, stomatal conductance and chlorophyll content of current and previous years' needles of Norway spruce were measured in May 1988, 205 days after the cessation of ozone fumigation during the summer of 1987. Rates of assimilation were consistently higher for both needle year age classes for ozone fumigated trees in comparison to control trees, although only statistically significant for part of the day for current year's needles. A 26% and 48% stimulation, overall, in mean daily rates of assimilation for current and previous years' needles of ozone fumigated trees was observed. This was due to an enhanced apparent quantum yield and light saturated rate of assimilation of ozone fumigated trees. The temperature response regression of assimilation versus temperature was also greater, such that at any given temperature, assimilation was higher for ozone treated trees than control trees. Stomatal conductance was greater for ozone fumigated trees than the controls, but this was only marginally statistically significant. Moreover, there was a consistent increase in chlorophyll content in both year classes in ozone-treated trees. These results are discussed in relation to a possible long term effect of ozone fumigation upon the processes of conifer winter hardening and spring de-hardening.     

Increasing risk for negative ozone impacts on vegetation in northern Sweden

Trends were found for increasing surface ozone concentrations during April-September in northern Sweden over the period 1990-2006 as well as for an earlier onset of vegetation growing season. The highest ozone concentrations in northern Sweden occurred in April and the ozone concentrations in April showed a strong increasing trend. A model simulation of ozone flux for Norway spruce indicated that the provisional ozone flux based critical level for forests in Europe is exceeded in northern Sweden. Future climate change would have counteracting effects on the stomatal conductance and needle ozone uptake, mediated on the one hand by direct effect of increasing air temperatures and on the other through increasing water vapour pressure difference between the needles and air. Thus, there is a substantial and increasing risk for negative impacts of ozone on vegetation in northern Sweden, related mainly to increasing ozone concentrations and an earlier onset of the growing season.     

Soil contamination by crude oil: impact on the mycorrhizosphere and on the revegetation potential of forest trees

In vitro and greenhouse biotests were carried out to study the effects of various concentrations of crude oil on the mycorrhizosphere and the ability of ectomycorrhizal fungi to colonise Norway spruce and poplar seedlings grown on contaminated soil. Ectomycorrhizal fungi grown in pure cultures showed a variety of reactions to crude oil, ranging from growth stimulation to total inhibition of growth, depending on the species of fungi. Germination of poplar and spruce seeds was not significantly affected. The growth of spruce seedlings was not affected by crude oil, whereas that of poplar seedlings was significantly reduced at high concentrations. None of the concentrations had any effect on the degree of ectomycorrhizal and endomycorrhizal colonisation of poplar. With spruce, however, the ectomycorrhizal fungi showed species-specific reactions to increasing concentrations, in accordance with the results of the pure culture test. The length of time between soil contamination and seeding affects both seedling growth and the mycorrhizal infection potential of the soil. The results confirm the importance of mycorrhizal fungi in the bioremediation of soils contaminated by crude oil.     

Simultaneous monitoring of profiles of polycyclic aromatic hydrocarbons in contaminated air with semipermeable membrane devices and spruce needles

Gaseous emissions of combusted electronic scrap, PVC, carpet and wood were monitored for polycyclic aromatic hydrocarbons (PAHs) by simultaneous use of semipermeable membrane devices (SPMDs) and shoots of spruce needles (Picea abies). It was found that phenanthrene, acenaphthylene and fluorene were the dominating PAHs in all samples. SPMDs and needles mainly sequestered PAH associated with the vapor phase. Particle-bound PAHs were only detected in small amounts, at which the needles tended to uptake more of these compounds in comparison to the SPMDs. Nevertheless, the logarithm of the concentrations of PAHs analyzed in both passive samplers after the same sampling period exhibited a significant linear correlation with correlation coefficients larger than 0.8073. SPMDs and spruce needles can complement each other in passive air sampling for compounds with a preference to the gas phase rather than aerosols.     

Uptake,translocation and fate of trichloroacetic acid in a Norway spruce/soil system

Trichloroacetic acid (TCA) is a secondary atmospheric pollutant formed by photooxidation of chlorinated solvents in the troposphere--it has, however, recently been ranked among natural organohalogens. Its herbicidal properties might be one of the factors adversely affecting forest health. TCA accumulates rapidly in conifer needles and influences the detoxification capacity in the trees. The aim of the investigations--a survey of which is briefly given here--was to elucidate the uptake, distribution and fate of TCA in Norway spruce. For this purpose young nursery-grown plants of Norway spruce (Picea abies (L.) Karst.) were exposed to [1,2-14C]TCA and the fate of the compound was followed in needles, wood, roots, soil and air with appropriate radio-indicator methods. As shown by radioactivity monitoring, the uptake of TCA from soil by roots proceeded most rapidly into current needles at the beginning of the TCA treatment and was redistributed at later dates so that TCA content in older needles increased. The only product of TCA metabolism/biodegradation found in the plant/soil-system was CO(2) (and corresponding assimilates). TCA biodegradation in soil depends on TCA concentration, soil humidity and other factors.     

Effects of deicing salt on the vitality and health of two spruce species,Picea abies Karst., and Picea glehnii Masters planted along roadsides in northern Japan

In northern Japan, the growth of Picea abies Karst., and Picea glehnii Masters, which have been planted along the highways, is often suppressed due to several environmental stresses. To examine the adverse effects of deicing salt, the primary source of stress,we measured needle life span, photosynthetic capacity, and water potential and transpiration rate of the two spruce species at a site with damaged trees, near the roadside and a site with healthy trees, located far from the highway. Results from the analysis showed large amounts of sodium and chlorine in the soil and snow at the damaged site. These elements had accumulated in the needles of the spruce. Moreover, physiological traits of the spruce, at the damaged site were also affected. Therefore, we concluded that poor physiological traits might be attributed to an accumulation of deicing salt in the needles, resulting in the suppression of tree growth.     

Status of sulphur in the foliage of Norway spruce (Picea abies (L.) Karst.) in relation to the mode of contamination

For decades, trees have been exposed to atmospheric S pollution (acid rains). They can thus fulfil their S requirements not only via the roots, but also via their needles. However, whether leaf-absorbed S has a different fate from that of root-absorbed S, or may be toxic to the plant, remains uncertain. Norway spruce trees have been contaminated with (35)SO(4)(2-) either via a nutrient solution, or via a spray, and their (35)S distribution has been analysed. In the case of foliar contamination, a high percentage of (35)S(-) was present in the form of SO(4)(2-), both on the surface and inside the youngest needles. In the case of root contamination, the (35)S of the youngest leaves was mainly incorporated into insoluble organic compounds. Older needles showed a different S distribution.     

Effects of acidic deposition on forest and aquatic ecosystems in New York State

Acidic deposition is comprised of sulfuric and nitric acids and ammonium derived from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia, respectively. Acidic deposition has altered soil through depletion of labile pools of nutrient cations (i.e. calcium, magnesium), accumulation of sulfur and nitrogen, and the mobilization of elevated concentrations of inorganic monomeric aluminum to soil solutions in acid-sensitive areas. Acidic deposition leaches essential calcium from needles of red spruce, making this species more susceptible to freezing injury. Mortality among sugar maples appears to result from deficiencies of nutrient cations, coupled with other stresses such as insect defoliation or drought. Acidic deposition has impaired surface water quality in the Adirondack and Catskill regions of New York by lowering pH levels, decreasing acid-neutralizing capacity, and increasing aluminum concentrations. Acidification has reduced the diversity and abundance of aquatic species in lakes and streams. There are also linkages between acidic deposition and fish mercury contamination and eutrophication of estuaries.