Natural forest expansion on reclaimed coal mines in Northern Spain: the role of native shrubs as suitable microsites

The characterization of suitable microsites for tree seedling establishment and growth is one of the most important tasks to achieve the restoration of native forest using natural processes in disturbed sites. For that, we assessed the natural Quercus petraea forest expansion in a 20-year-old reclaimed open-cast mine under sub-Mediterranean climate in northern Spain, monitoring seedling survival, growth, and recruitment during 5 years in three contrasting environments (undisturbed forest, mine edge, and mine center). Seedling density and proportion of dead branches decreased greatly from undisturbed forest towards the center of the mine. There was a positive effect of shrubs on Q. petraea seedling establishment in both mine environments, which increase as the environment undergoes more stress (from the mine edge to the center of the mine), and it was produced by different shrub structural features in each mine environment. Seedling survival reduction through time in three environments did not lead to a density reduction because there was a yearly recruitment of new seedlings. Seedling survival, annual growth, and height through time were greater in mine sites than in the undisturbed forest. The successful colonization patterns and positive neighbor effect of shrubs on natural seedlings establishment found in this study during the first years support the use of shrubs as ecosystem engineers to increase heterogeneity in micro-environmental conditions on reclaimed mine sites, which improves late-successional Quercus species establishment.     

Ecological risk assessment of organic waste amendments using the species sensitivity distribution from a soil organisms test battery

Safe amendment rates (the predicted no-effect concentration or PNEC) of seven organic wastes were estimated from the species sensitivity distribution of a battery of soil biota tests and compared with different realistic amendment scenarios (different predicted environmental concentrations or PEC). None of the wastes was expected to exert noxious effects on soil biota if applied according either to the usual maximum amendment rates in Europe or phosphorus demands of crops (below 2 tonnes DM ha⁻¹). However, some of the wastes might be problematic if applied according to nitrogen demands of crops (above 2 tonnes DM ha⁻¹). Ammonium content and organic matter stability of the studied wastes are the most influential determinants of the maximum amendment rates derived in this study, but not pollutant burden. This finding indicates the need to stabilize wastes prior to their reuse in soils in order to avoid short-term impacts on soil communities.     

Comparison of solid-phase and eluate assays to gauge the ecotoxicological risk of organic wastes on soil organisms

Development of methodologies to assess the safety of reusing polluted organic wastes in soil is a priority in Europe. In this study, and coupled with chemical analysis, seven organic wastes were subjected to different aquatic and soil bioassays. Tests were carried out with solid-phase waste and three different waste eluates (water, methanol, and dichloromethane).Solid-phase assays were indicated as the most suitable for waste testing not only in terms of relevance for real situations, but also because toxicity in eluates was generally not representative of the chronic effects in solid-phase.No general correlations were found between toxicity and waste pollutant burden, neither in solid-phase nor in eluate assays, showing the inability of chemical methods to predict the ecotoxicological risks of wastes. On the contrary, several physicochemical parameters reflecting the degree of low organic matter stability in wastes were the main contributors to the acute toxicity seen in collembolans and daphnids.     

Human exposure to fluoride from tea (Camellia sinensis) in a volcanic region—Canary Islands,Spain

Fluoride is highly present in the environment, especially in water and its derivatives. Excessive fluoride contribution to diet poses a health risk. Tea leaves accumulate fluoride and the consumption of tea (Camellia sinensis) could pose a risk to human by the excessive fluoride intake. Ninety tea samples were analyzed by potentiometry using a selective fluoride ion electrode. Mixed tea samples (2.82?±?1.11 mg/L) and black tea samples (2.28?±?0.79 mg/L) recorded the highest fluoride levels. The contribution of drinking water is important for increasing fluoride levels in teas. The daily consumption of two cups (250 mL per cup) of mixed and black teas prepared with La Laguna tap water does pose a health risk for children (4–8 years old) because of the high contribution percentages (74.4% and 63.6%, respectively) of the Tolerable Upper Intake Level set in 2.5 mg/day by the EFSA (European Food Safety Authority). A minor consumption in children (4–8 years old) and adults during pregnancy is advisable.

     

Performance comparison of commercial TiO2: separation and reuse for bacterial photo-inactivation and emerging pollutants photo-degradation

This research aims to compare the disinfection and degradation effectiveness in water of a commercial suspension of nano-TiO₂ (TiO₂Levenger) with the standard TiO₂Degussa P25. Photo-inactivation and photo-degradation experiments were conducted with UVA-vis light. Concerning the disinfection, the effects of TiO₂ dose (0–2 g/l), water matrix, bacterium type (Gram-positive or Gram-negative), and bacterial regrowth after the photo-treatments were studied for each catalyst. The experimental results show that Enterococcus sp. (Gram-positive) was more resistant to the photo-treatments than Escherichia coli (Gram-negative) for both catalyst; however, postirradiation trends showed similar behavior for both bacteria, favoring regrowth for short-treated cells and decay for longer-treated ones. Caffeine was selected as a model substance of pharmaceuticals and personal care products. In terms of caffeine removal, the effects of TiO₂ dose (0–2 g/l) and water matrix were analyzed. Besides, the comparison between mechanical coagulation-flocculation-decantation and simple decantation of TiO₂ was carried out. The results show that simple decantation allowed the recovery of 97.5% of TiO₂ Degussa P25 and TiO₂ Levenger within 1 day of simple decantation, while applying the proposed mechanical coagulation-flocculation decantation 99.7% of recovery of both catalysts was achieved in 2 hours. Finally, the subsequent reuse of both catalysts was proved with little loss of efficiency in terms of photo-disinfection during the four cycles. Nevertheless, the standard TiO₂ Degussa P25 photo-degradation efficiency of caffeine decreases considerably as compared to commercial suspension of TiO₂ Levenger concerning the reutilization.

     

Sorption of 2,4-d on natural and organic amended soils of different characteristics

The effect of one organic amendment consisting of an urban waste compost (UWC) was assessed on the sorption properties of the herbicide 2,4-D on four soils of different physicochemical characteristics. The soils chosen were a Typic Haphorthod (ST), a Typic Endoaquept (SR), an Entic Pelloxerert (TO), and a Typic Eutrochrept (AL). Adsorption experiments were performed on the original soils, and on mixtures of these soils with UWC at a rate of 6.25% (w/w). These mixtures were used just after preparation, and after aging for 8 and 25 weeks. 2,4-D adsorption was the highest on ST soil, whereas the lowest adsorption was for SR soil. This behavior is related to the high amount of organic matter (OM) and amorphous iron and aluminum oxides content on soil ST, whereas soil SR had the lowest OM content and specific surface area of the soils of this study. Addition of exogenous OM to soils caused an increase in the 2,4-D adsorption by three of the soils treated with UWC, with the only exception being ST soil, due to an observed decrease in its specific surface area. The adsorbed amounts of the herbicide on aged organic fertilized soils diminished in three of the amended soils, but was still greater than on unammended soils. In contrast, the ST soil showed the largest adsorption for unammended soil.     

Synthesis and Characterization of Lactic Acid Oligomers: Evaluation of Performance as Poly(Lactic Acid) Plasticizers

The use of fully bio-based and biodegradable materials for massive applications, such as food packaging, is an emerging tendency in polymer research. But the formulations proposed in this way should preserve or even increase the functional properties of conventional polymers, such as transparency, homogeneity, mechanical properties and low migration of their components to foodstuff. This is not always trivial, in particular when brittle biopolymers, such as poly(lactic acid) (PLA), are considered. In this work the formulation of innovative materials based on PLA modified with highly compatible plasticizers, i.e. oligomers of lactic acid (OLAs) is proposed. Three different synthesis conditions for OLAs were tested and the resulting additives were further blended with commercial PLA obtaining transparent and ductile materials, able for films manufacturing. These materials were tested in their structural, thermal and tensile properties and the best formulation among the three materials was selected. OLA with molar mass (M_n) around 1,000 Da is proposed as an innovative and fully compatible and biodegradable plasticizer for PLA, able to replace conventional plasticizers (phthalates, adipates or citrates) currently used for films manufacturing in food packaging applications.     

Male Iberian rock lizards may reduce the costs of fighting by scent matching of the resource holders

Animals should adopt strategies to minimize the costs of intraspecific aggressive interactions. For example, individuals should be able to identify resource holders in advance and avoid fighting with them because residents are generally more likely than intruders escalate aggression. It has been suggested that scent marks function mainly to allow competitor assessment by conveying the costs of entering a scent-marked area. Individuals may identify territory owners by comparing the scent of substrate marks with the scent of any conspecific they encounter nearby, assessing whether these two scents match or not, a mechanism known as scent matching. Here, we examined the response of male Iberolacerta cyreni lizards to areas scent-marked by other males and the potential role of scent matching in agonistic interactions. We designed a laboratory experiment where we allowed a male to explore the scent-marked substrate of another male, and then we immediately staged agonistic encounters in a nearby clean neutral area with either the male that had produced the scent marks (matching treatment) or with a different non-matching individual male. The higher chemosensory exploratory rates of substrate scent marks in comparison to clean substrates suggested that males detected and spent more time exploring scent marks to obtain information on the donor male. Moreover, this information was later used to decide the fighting strategy. Intruding males delayed time until the first agonistic interaction, reduced the intensity of fights and the number of aggressive interactions, and won less interactions with males which scent matched that of scent marks (because they would be considered as the territory owners) than with other non-matching individuals. Our results show that male I. cyreni lizards use scent matching as a mechanism to assess the ownership status of other males, which could contribute to modulate intrasexual aggression, reducing costs of agonistic interactions.     

Alkylphenols and polycyclic aromatic hydrocarbons in eastern Mediterranean Spanish coastal marine bivalves

This paper reports the first results on alkylphenol pollution in edible bivalves from the Spanish coast. Two sampling campaigns (July 2006 and July 2007) were carried out to determine the concentration of nonylphenol (NP), octylphenol (OP), and eight polycyclic aromatic hydrocarbons (PAHs) in wild mussels (Mytilus galloprovincialys) and clams (Donax trunculus) at 14 sampling sites along the eastern Mediterranean Spanish coast. The results show that NP is the predominant alkylphenol, being the port of Valencia the most polluted area (up to 147 ??g/kg wet weight in clams). Moving away from the ports the concentration of NP in bivalves decreased. OP concentration was below its detection limit in most of the studied areas and its maximum concentration (6 ??g/kg w/w) was measured in clams from the port of Sagunto. The presence of low levels of PAHs was observed in most of the studied areas. The total PAHs concentration (i.e., sum of the eight measured PAHs) achieved a maximum value of 10.09 ??g/kg w/w in the north coast of Valencia city. The distribution pattern of the individual PAHs showed that both pollution sources petrogenic and pyrolytic were present in the sampled areas. Fluoranthene was the most abundant PAH in mussels while benzo(b)fluoranthene in clams. The maximum concentration of 10 ??g/kg w/w for benzo(a)pyrene established by the European Commission was never reached, indeed sampled bivalves showed concentrations 10 times lower than this reference value. Thus, they can be considered safe for human consumption. Despite the low contamination levels, the results show an overall pollution of bivalves by alkylphenol and PAHs as well as an increment in the number of polluted areas from 2006 to 2007. Thus, periodical sampling campaigns should be carried out to monitor the long-term tendency of these toxic and persistent pollutants.