In forest soils along vertical profiles located in different parts of the Alps, concentrations of persistent organic pollutants (POPs), namely organochlorine pesticides (OCPs) like dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCH), heptachlor, aldrin, dieldrin and mirex, were measured. Though local characteristics of the sites are influenced by numerous factors like orographic and meteorological parameters, forest stand characteristics and humus parameters, we ascertained a marked vertical increase of concentrations of some organochlorine compounds in the soil. On the basis of climatological values of each site, we found that the contamination increase with altitude can be ascribed to a certain ‘cold condensation effect’. In addition, the perennial atmospheric deposition of POPs is controlled by precipitation. Other key parameters explaining the accumulation of POPs are the soil organic carbon stocks, the turnover times, the re-volatilisation and degradation processes, which vary with altitude. Caused by temperature-dependent processes regarding deposition, re-volatilization and decomposition of POPs, the concentration of organochlorine pesticides varies in the Alpine region with altitude.

On Zugspitze (2670 m a.s.l.), Alps, higher concentrations were observed during a winter than during a summer measurement campaign of PAHs, chlorobenzenes (43.6 vs. 2.0 pg m−3) and DDTs (3.7 vs. 1.2 pg m−3), while hexachlorocyclohexanes and PCBs were found at similar levels. The PCB, HCH and DDT levels are among the lowest ever reported from outside the Arctic. Mostly lower levels were found in samples collected in summer than in winter despite a significant boundary layer air influence, but no such influence on samples collected during the winter campaign. Boundary layer influence was quantified by Lagrangian particle dispersion model retroplume analyses. Photochemical lifetimes corresponding to kOH < 1.5 × 10−12 cm3 molec−1 s−1 are found for p,p′-DDT, kOH < 0.75 × 10−12 cm3 molec−1 s−1 for p,p′-DDE and kOH < 1.0 × 10−12 cm3 molec−1 s−1 for p,p′-DDD. Persistent organic pollutants have been observed at a mountain site in the Alps showing that very low concentrations can be found in the free troposphere.

We studied the responses of micropropagated, northern provenances of downy, mountain and silver birches to elevated ozone (O₃) and changing climate using open-top chambers (OTCs). Contrary to our hypothesis, northern birches were sensitive to O₃, i.e. O₃ levels of 31-36 ppb reduced the leaf and root biomasses by -10%, whereas wood biomass was affected to a lesser extent. The warmer and drier OTC climate enhanced growth in general, though there were differences among the species and clones, e.g. in bud burst and biomass production. Inter- and intra-specific responses to O₃ and changing climate relate to traits such as allocation patterns between the above- and belowground parts (i.e. root/shoot ratio), which further relate to nutrient and water economy. Our experiments may have mimicked future conditions quite well, but only long-term field studies can yield the information needed to forecast responses at both tree and ecosystem levels. Northern birches are responsive to ambient ozone levels.

Two studies were conducted to determine a feasible and practical phytoremediation strategy for Zn-contaminated soils. The aim of the first study was to identify promising plant species capable of Zn remediation for the soils and climatic conditions of British Columbia. The purpose of the second study was to assess the effects of soil amendments in modifying the soil properties and providing the right conditions for the plants to immobilise Zn. Promising plants for phytostabilisation in the first study (Lolium perenne, Festuca rubra and Poa pratensis) were tested in the presence of soil amendments (lime, phosphate and compost, both individually and in combination) in the second study. The efficiency of treatments to stabilise Zn was based on Zn fractionation in the soil and on absorption and partitioning of Zn in plants. Maximum Zn immobilisation was achieved in the soil by a combination of lime, phosphate and compost, in conjunction with growth of P. pratensis.

The variations of tropospheric ozone levels was assessed for the first time in the Boukornine National Park (N.E. Tunisia) by detection of leaf injury development on Nicotiana tabacum “Bel-W3” exposed to environmental conditions during summer 2004. Two cultivars of tobacco (Nicotiana tabacum), Bel-W3 (sensitive) and Bel-B (resistant to ozone), were used for this biomonitoring study. These cultivars were dispersed in 24 different biostations, according to a square grid mesh, every 2 weeks. Four successive cultures were utilized to follow the ozone levels inside the park during the summer exposure period. Levels of ozone may vary in time and space depending on the local environmental and meteorological conditions. The results showed a positive correlation between ozone concentration and foliar injury index (FII; r = 0.958; p < 0.05). A significant positive correlation was observed between the FII of Bel-W3 tobacco plant and AOT40 (accumulated over the threshold of 40 ppb). The altitude appeared to be the most important variable explaining the variation of ozone pollution with the highest correlation coefficient (r = 0.964; p < 0.0001). The altitude was followed by topography for the prediction of ozone concentration levels. Maximal temperature was also an important factor in addition to the others in determining the FII and was negatively correlated with the FII (r = −0.979; p < 0.05). Average ambient ozone levels were positively linked to plant leaf damage. The ozone profile characterizing the study area was primarily influenced by wind direction and speed in relation to intercontinental transport, in addition to the local influence of motor vehicles traffic flow in the Tunis region.

Background, aim, and scope Lindane, technically 1, 2, 3, 4, 5, 6-hexachlorocyclohexane (γ- HCH), is the most commonly detected organochlorine pesticide from diverse environmental compartments. Currently, India is the largest consumer and producer of lindane in the world. The production of lindane results in the generation of large quantities of waste HCH isomers (mainly α-, β- and δ-). All these isomers are toxic and have a long-range environmental transport potential. The aim of this study was to monitor the seasonal variation of HCH isomers in an open soil-plant-rhizospheric soil system of a contaminated industrial area. For this, selected plant species and their rhizospheric soil (soil samples collected at a depth range of 0-45 cm near to the root system) and open soil samples (soil samples collected (0-30 cm depth) from 1-1.5 m away from the plant root system) were collected for 2 years (two summer seasons and two winter seasons). Materials and methods Seven plant species along with their rhizospheric soil and open soil samples were collected seasonally from different parts of the industry. Plant samples were separated into root, leaf and stem. HCH isomers in plant and soil samples were extracted by matrix solid-phase dispersion extraction (MSPD) and Soxhlet extraction, respectively, followed by GC-ECD. The seasonal difference in occurrence of HCH isomers in plant samples with their respective soil-system was studied by multivariate statistical approaches. Results The mean concentration of total HCH in plant samples, open soil and rhizospheric soil samples were found in the range of 14.12 to 59.29 mg kg⁻¹; 38.64 to 104.18 mg kg⁻¹ and 8.38 to 26.05 mg kg⁻¹, respectively. Cluster grouping reveals that S. torvum and W. somnifera can accumulate more HCH than other studied species. Discussion There was a marked seasonal difference in the occurrence of HCH isomers in plant samples (p < 0.05) and open soil samples (p < 0.01). Comparatively higher levels of HCH isomers were detected from plant samples during summer, while higher levels of HCH isomers were detected from soil samples during the winter season. There was no significant difference in seasonal variation of HCH isomers in rhizospheric soil samples; however, total HCH in rhizospheric soil samples were 4 to 5-fold lower than the open soil samples. The total concentration of HCH isomers in roots is linearly related to their rhizospheric HCH level. Conclusions HCH isomers were detected in open soil, plants and rhizospheric soil samples. Monitoring studies clearly revealed that the above-mentioned industrial area is contaminated with all major isomers of HCH. Occurrence of all these isomers in the study area point out the lack of sustainable management practices of this industry for protecting the area from hazardous waste. The analytical results confirmed that accumulation depends upon the plant species, soil and climatic conditions. Recommendations and perspectives Recently, α-, β- and γ-HCH have been nominated by the POPs Reviewing Committee for inclusion into the Stockholm Convention to address the HCH contamination on a global level. Therefore, there is an urgent need to stop the production of lindane and remediate contaminated soil sites. Based on the monitoring studies, the promising species like W. somnifera and S. torvum may be selected for the on-site phytoremediation of HCH-contaminated soil. The mismanagement of HCH residues from the organochlorine industry and their contemporary relevance often after decades of their deposition is one key example demonstrating the necessity to evaluate the waste deposits of the respective organochlorine productions and need for a strict waste management, and the necessity of an integrated pollution prevention and control strategy for the whole organochlorine industry including also the developing countries.