Efficacy of Si fertilization to modulate the heavy metals absorption by barley (Hordeum vulgare L.) and pea (Pisum sativum L.)

Silicon-based fertilizers and soil amendments can have direct and indirect positive influences on cultivated plants. The solid forms of Si-based substances, the most widespread in use, are efficient only at high application rates due to their low level of solubility. Several types of Si-based substances such as fumed silica, slags from the iron and steel industry, modified slags, and a Si-rich product were tested using barley and pea as silicon accumulative and non-accumulative plants, respectively, at two application rates. The plants were grown under toxic concentrations of heavy metals in a greenhouse. Si-rich materials high in water-soluble Si had a positive effect at both the low and high application rates, and for both plant species. This type of substance can be regarded as Si fertilizer, demonstrating greater efficiency at a low application rate and lessened efficiency at a high application rate for protection of the cultivated plants against accumulation of the heavy metals.

     

Gas–particle partitioning of persistent organic pollutants in the Western Balkan countries affected by war conflicts

Background, aim, and scope  

Bombing and destruction of the industrial and military targets accompanied by complete or incomplete combustion during the war conflict and NATO operation in former Yugoslavia caused the emission of persistent organic pollutants into the atmosphere, water, and soil. A total of 129 ambient air samples from 24 background, urban, and industrial sites, including hot spots, were collected to assess a gas–particle partitioning behavior of various persistent organic pollutants.     

TBT pollution and effects in molluscs at US Virgin Islands,Caribbean Sea

An almost ubiquitous occurrence of imposex and butyltins in the molluscs from US Virgin Islands gives evidence to a widespread contamination with the antifouling agent tributyltin (TBT), which most likely is related to a relatively intense ship traffic. Three different muricid neogastropod species Thais deltoidea, Thais rustica and Purpura patula all seem to have potential as suitable and sensitive bioindicators for assessing levels and effects of TBT pollution in coastal areas including coral reefs in the Caribbean Sea. However, considerable interspecies differences in especially accumulation potential of butyltins were seen in this study. Furthermore, a high accumulation potential of TBT in the edible gastropod West Indian topshell (Cittarium pica) was found, despite that no signs of imposex were observed in this archaeogastropod species.     

Impact of water saturation level on arsenic and metal mobility in the Fe-amended soil

The impact of water saturation level (oxidizing-reducing environment) on As and metal solubility in chromium, copper, arsenic (CCA)-contaminated soil amended with Fe-containing materials was studied. The soil was mixed with 0.1 and 1 wt% of iron grit (Fe(0)) and 1, 7 and 15 wt% of oxygen scarfing granulate (OSG, a by-product of steel processing). Solubility of As and metals was evaluated by a batch leaching test and analysis of soil pore water. Soil saturation with water greatly increased As solubility in the untreated as well as in the Fe-amended soil. This was related to the reductive dissolution of Fe oxides and increased concentration of As(III) species. Fe amendments showed As reducing capacity under both oxic and anoxic conditions. The cytotoxicity of the soil pore water correlated with the concentration of As(III). The Fe-treatments as well as water saturation of soil were less significant for the solubility of Cu, Cr and Zn than for As. The batch leaching test used for waste characterization substantially underestimated As solubility that could occur under water-saturated (anaerobic) conditions. In the case of soil landfilling, other techniques than Fe-stabilization of As containing soil should be considered.     

Comparing the impacts of hiking, skiing and horse riding on trail and vegetation in different types of forest

Nature-based tourism in protected areas has increased and diversified dramatically during the last decades. Different recreational activities have a range of impacts on natural environments. This paper reports results from a comparison of the impacts of hiking, cross-country skiing and horse riding on trail characteristics and vegetation in northern Finland. Widths and depths of existing trails, and vegetation on trails and in the neighbouring forests were monitored in two research sites during 2001 and 2002. Trail characteristics and vegetation were clearly related to the recreational activity, research site and forest type. Horse trails were as deep as hiking trails, even though the annual number of users was 150-fold higher on the hiking trails. Simultaneously, cross-country skiing had the least effect on trails due to the protective snow cover during winter. Hiking trail plots had little or no vegetation cover, horse riding trail plots had lower vegetation cover than forest plots, while skiing had no impact on total vegetation cover. On the other hand, on horse riding trails there were more forbs and grasses, many of which did not grow naturally in the forest. These species that were limited to riding trails may change the structure of adjacent plant communities in the long run. Therefore, the type of activities undertaken and the sensitivity of habitats to these activities should be a major consideration in the planning and management of nature-based tourism. Establishment of artificial structures, such as stairs, duckboards and trail cover, or complete closure of the site, may be the only way to protect the most sensitive or deteriorated sites.     

The value of the environment – Is it a matter of approach?

This paper discusses why estimates of the benefits of reduced air pollution differ in accordance with the approach used. Estimates based on bottom-up studies of the damage costs related to air pollution usually turn out much lower than estimates based on assessments of the utility of reduced air pollution, obtained for instance by willingness to pay assessments. This is usually explained by the fact that the willingness to pay approach includes the utility aspect of non-market values, and for this reason, it is often preferred to the damage cost approach. This is, however, not the whole story. The paper shows why alternative approaches should not be considered as being in conflict, but rather as means to get supplementary information necessary to put a value on environmental quality. Information from bottom-up assessments of damage costs and from studies of the willingness to pay is used in a macroeconomic model to carry out an evaluation of the social costs of energy saving measures in Hungary.     

Simplified determination of lipophilic metabolites of nonylphenol ethoxylates: method development and application in aqueous samples from Buenos Aires, Argentina

In the present work we have developed an analytical methodology for the determination of nonylphenol (NP) and nonylphenol mono- and di-ethoxylates (NP1EO and NP2EO) in water samples. The applicability of this methodology was proved by means of the analysis of environmentally relevant aqueous samples from Buenos Aires. This constitutes a starting point for a rigorous assessment of the incidence of NPnEO surfactants in Argentina, as only very few, qualitative or semi-quantitative data on the occurrence of these compounds in local systems were available up to this time. Enrichment of the analytes was carried out by solid-phase extraction on a C-18 sorbent, followed by elution with ethyl acetate. Normal-phase high performance liquid chromatography on an amino-silica column and fluorescence detection at excitation-emission wavelengths of 230-300 nm were employed for separation and quantification of the analytes. Confirmation of peak assignment in selected real samples was performed by off-line coupling HPLC with GC-MS analysis. A non-polar GC capillary column was used, and a characteristic peak pattern was obtained for the alkyl chain isomers of each ethoxylated homologue and NP. GC-MS analyses yielded in all cases purity levels higher than 80% for the HPLC collected fractions. The elevated concentrations found for the estrogenic metabolites of NPnEO are in accordance with an unrestricted use of this class of non-ionic surfactants in the country.     

Uptake of some selected aquatic pollutants in semipermeable membrane devices (SPMDs) and the polar organic chemical integrative sampler (POCIS)

The uptake characteristics of semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCISs) were examined for mono, di and tributyltin, triphenyltin, pyrene, benzo[a]pyrene, 4-tert-butylphenol, 4-n-nonylphenol, PCBs 77 and 153, PBDE 47, lindane, triclosan and DDT. Exposure in a flow through system continued for 28 days with samplers removed every 7 days in order to study the relevant uptake kinetics. Uptake remained linear for POCISs with sampling rates (Rs) of up to 0.2 L d(-1). For SPMDs uptake varied from linear to approaching equilibrium with Rs values of up to 14 L d(-1). 7 out of 9 results for SPMDs could be explained by an empirical model (nonylphenol and lindane were exceptions). None of the four organo-tin compounds studied were detected in POCISs and only tributyltin was accumulated significantly by SPMDs. The establishment of these sampling rates allows the calculation of time weighted water concentrations for several important contaminants. Using presented methods, sampling rates and exposure conditions, theoretical detection limits for selected compounds by SPMDs were between 11-68 pg L(-1), which is well below the environment quality standard proposed for those compounds that are included in the European Water Framework Directive.     

Assessing benthic community condition in Chesapeake Bay: does the use of different benthic indices matter?

Federal and state environmental agencies conduct several programs to characterize the environmental condition of Chesapeake Bay. These programs use different benthic indices and survey designs, and have produced assessments that differ in the estimate of the extent of benthic community degradation in Chesapeake Bay. Provided that the survey designs are unbiased, differences may exist in the ability of these indices to identify environmental degradation. In this study we compared the results of three indices calculated on the same data, and the assessments of two programs: the Chesapeake Bay Program and the Mid-Atlantic Integrated Assessment (MAIA). We examined the level of agreement of index results using site-based measures of agreement, evaluated sampling designs and statistical estimation methods, and tested for significant differences in assessments. Comparison of ratings of individual sites was done within separate categories of water and sediment quality to identify which indices summarize best pollution problems in Chesapeake Bay. The use of different benthic indices by these programs produced assessments that differed significantly in the estimate of degradation. A larger fraction of poor sites was classified as good by the Environmental Monitoring and Assessment Program’s Virginian Province and MAIA benthic indices compared to the Chesapeake Bay benthic index of biotic integrity, although overall classification efficiencies were similar for all indices. Differences in survey design also contributed to differences in assessments. The relative difference between the indices remained the same when they were applied to an independent dataset, suggesting that the indices can be calibrated to produce consistent results.     

Flexible and robust strategies for waste management in Sweden

Treatment of solid waste continues to be on the political agenda. Waste disposal issues are often viewed from an environmental perspective, but economic and social aspects also need to be considered when deciding on waste strategies and policy instruments. The aim of this paper is to suggest flexible and robust strategies for waste management in Sweden, and to discuss different policy instruments. Emphasis is on environmental aspects, but social and economic aspects are also considered. The results show that most waste treatment methods have a role to play in a robust and flexible integrated waste management system, and that the waste hierarchy is valid as a rule of thumb from an environmental perspective. A review of social aspects shows that there is a general willingness among people to source separate wastes. A package of policy instruments can include landfill tax, an incineration tax which is differentiated with respect to the content of fossil fuels and a weight based incineration tax, as well as support to the use of biogas and recycled materials.