Determination of lipid peroxidation and cytotoxicity in calcium, magnesium, titanium and hectorite (SHCa-1) suspensions

This paper reports data on the relative ability of CaO, CaCl₂, MgO, MgCl₂, TiO₂, and hectorite (SHCa-1) to induce oxidative stress (as determined by lipid peroxidation, LP) in biological matrices. The effectiveness of structural (oxide form) versus soluble Ca and Mg to induce LP is compared. An assessment on cytotoxicity as affected by soluble and structural Ca, Mg, TiO₂ and SHCa-1 is also addressed. LP was screened and monitored using the Thiobarbituric Acid Reactive Substances (TBARS). The extent of TBARS production was found to vary with the type and initial concentration of the soluble or structural cation, Ca or Mg respectively. Obtained results showed higher magnitude values for the latter set of experiments. In the presence of TiO₂ no significant TBARS production was detected pointing out a negligible effect of TiO₂ on LP. At solid concentrations ca. 100 ppm, CaO appears to be more effective than SHCa-1 to induce LP. By contrast at ca. 25 ppm, MgO appears to be more effective than the clay mineral. The SHCa-1 LP-inducing activity has been proven to closely relate to structural Ca. The prevalence of mechanisms that may induce LP but not cytotoxicity (as determined by cell growth inhibition) was also addressed. Results on cell growth inhibition as affected by soluble and structural Ca, Mg, TiO₂ and hectorite provide evidence to support that structural Ca or Mg brings about significantly higher variations than soluble Ca.     

Nitrogen deposition effects on Mediterranean-type ecosystems: an ecological assessment

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling.     

Enrichment of trace elements in the clay size fraction of mining soils

Reactive waste dumps with sulfide minerals promote acid mine drainage (AMD), which results in water and soil contamination by metals and metalloids. In these systems, contamination is regulated by many factors, such as mineralogical composition of soil and the presence of sorption sites on specific mineral phases. So, the present study dedicates itself to understanding the distribution of trace elements in different size fractions (<2-mm and <2-μm fractions) of mining soils and to evaluate the relationship between chemical and mineralogical composition. Cerdeirinha and Penedono, located in Portugal, were the waste dumps under study. The results revealed that the two waste dumps have high degree of contamination by metals and arsenic and that these elements are concentrated in the clay size fraction. Hence, the higher degree of contamination by toxic elements, especially arsenic in Penedono as well as the role of clay minerals, jarosite, and goethite in retaining trace elements has management implications. Such information must be carefully thought in the rehabilitation projects to be planned for both waste dumps.     

Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia

Polybrominated diphenyl ethers (PBDEs) and naturally-produced organobrominated compounds, such as methoxylated PBDEs (MeO-PBDEs), have been scarcely studied in the Southern Hemisphere. Yet, sources of the latter group of compounds were found in Southern regions, specifically in Australia. The environmental distribution and biomagnification potential of organobrominated compounds were therefore investigated in a representative aquatic food chain (invertebrates and fish) from the Sydney Harbour, Australia. Mean PBDE concentrations ranged from 6.4 ng/g lipid weight (lw) in squid to 115 ng/g lw in flounder. BDE 47 was the dominant congener, followed by BDE 100. Mean levels of MeO-PBDEs (sum of congeners 2’-MeO-BDE 68 and 6-MeO-BDE 47) were as high as 110 ng/g lw in tailor, with a slight dominance of 2’-MeO-BDE 68. Polybrominated hexahydroxanthene derivates (PBHDs), another class of naturally-produced compounds, were found at variable concentrations and ranged from 4.7 ng/g lw in fanbelly and 146 ng/g lw in tailor. The tribrominated PBHD isomer dominated in the samples, except for luderick and squid. The lower levels of PBDEs found in luderick from the harbour compared to those obtained from the upper Parramatta River indicated a terrestrial (anthropogenic) origin of PBDEs, while the higher levels of MeO-PBDEs and PBHDs in the samples from the harbour confirmed the marine (natural) origin of these compounds. The highest trophic magnification factor (TMF) was found for sum PBDEs (3.9), while TMFs for sum MeO-PBDEs and sum PBHDs were 2.9 and 3.4, respectively. This suggests that biomagnification occurs in the studied aquatic food chain for anthropogenic brominated compounds, but also for the naturally-produced organobromines.     

New roles for farming in a differentiated countryside: the Portuguese example

Throughout Europe, the role of farming as the private provider of public goods and services increasingly valuated by society is today generally acknowledged. Furthermore, in the turn towards rural development concerns, multifunctionality as an attribute of rural space has emerged, justifying the territorial approach of farming. The situation facing the multifunctionality demand is nevertheless not the same in all European regions, which by all means is getting strengthened in the transition towards post-productivism. In some regions, there is a productivist orientation and production has a dominant economic role, while others will need to be supported on other functions to survive economically and socially, or may be best suited to environmental functions alone. The vocation of the rural territories is different, and thus also the functions they are able to support. This paper discusses the concept of multifunctionality of the rural areas, and defines a possible methodological approach towards the identification of the different types of rural areas in Europe, based on the identification of ideal types, through the analysis of selected indicators. The empirical application has been developed for the Portuguese Ministry of Agriculture, aiming at assessing the differentiated characteristics and dynamics of the Portuguese rural territory. Analyzing data from 1990 and 2000, at municipal level, three dimensions have been considered: the land cover, the agricultural sector and the rural community. Combining the three analyses, it was possible to identify different vocations of the rural space, and the role that farming could have in the future for the multifunctionality of the territory. Accordingly, the municipalities have been grouped in types, pre-defined as ideal types. This was a first attempt to understand the differentiation of the rural territory in Portugal. For decision-making it should be further developed. It nevertheless shows that there is clear differentiation concerning the possible landscape functions to be developed between regions and a possible way to assess. It also shows that a territorial approach to agriculture may be the key for the maintenance of the sector in many areas where production by itself, as it has been know until now, may be severely threatened.     

Oxidative properties of ambient PM2.5 and elemental composition: Heterogeneous associations in 19 European cities

We assessed the extent to which constituents of PM_2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM_2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM_2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.     

Butyltin levels in several Portuguese coastal areas

This work aimed to report present levels (2007–2008 sampling) of tri- (TBT), di- (DBT), and monobutyltin (MBT) in surface sediments from 11 Portuguese coastal sites and discuss the evolution of BTs contamination in the last two decades. All the samples revealed quantifiable values of TBT, DBT, and MBT with total butyltin concentrations between 1 and 565 ng/g (of Sn in dry sediment). Maximum level of TBT, 66 ng/g, was observed in Sado estuary, at Lisnave site, in the proximity of a big shipyard. MBT decreased site by site by the same order as DBT and TBT did, but its concentrations were much higher in many cases, denoting that TBT contamination was much higher in the past. A comparison with the available previous data confirmed a marked decrease of TBT contamination all over the last years, indicating that the main sources of TBT in Portuguese coastwise stopped effectively.     

Organic speciation of atmospheric particles in Alvão Natural Park (Portugal)

PM₁₀ continental rural background aerosols were collected during a summer field campaign (August–September 2006) at Lamas de Ôlo in the upper zone of the Alvão Natural Park, a mountain region of northern Portugal. In addition to the determination of the carbonaceous content by a thermal–optical method, the organic speciation of aerosols was performed by gas chromatography–mass spectrometry in an effort to evaluate photo-oxidation products of biogenic volatile organic compounds and other markers for source characterization. The detailed analysis revealed relatively high concentrations of polyols and short-chain dicarboxylic, tricarboxylic, hydroxycarboxylic, and oxocarboxylic acids, many of which are thought to be indicators of secondary aerosol formation, accounting for about 70% of global chromatographically resolved mass. Major photo-oxidation products of α- and β-pinene have been detected. The tracers for the photo-oxidation of isoprene comprise two diastereoisomeric 2-methyltetrols, C₅-alkene triols, and 2-methylglyceric acid, which have only recently been elucidated. In addition, the occurrence of levoglucosan and other biomass combustion tracers indicates that the site was affected by wildfires. This source contributed to more than 80% of the organic carbon mass during a period of strong forest fire influence.     

Vegetable and synthetic tannins induce hormesis/toxicity in sea urchin early development and in algal growth

Mimosa tannin and phenol-based synthetic tannin (syntan) were tested for toxicity to sea urchin (Paracentrotus lividus and Sphaerechinus granularis) early development and to marine algal growth (Dunaliella tertiolecta). Sea urchin embryogenesis was affected by vegetable tannin and syntan water extracts (VTWE and STWE) at levels >or=1mg/L. Developmental defects were significantly decreased at VTWE and STWE levels of 0.1 and 0.3mg/L when control cultures displayed suboptimal quality, i.e. <70% "viable" (normal or retarded) larvae. Fertilization success of sea urchin sperm was increased up to 0.3 mg/L STWE or VTWE, then was inhibited by increasing tannin levels (1-30 mg/L). Offspring abnormalities, following sperm exposure to VTWE or STWE, showed the same shift from hormesis to toxicity. Cell growth bioassays in D. tertiolecta exposed to VTWE or STWE (0.1-30 mg/L) showed non-linear concentration-related toxicity. Novel criteria are suggested in defining control quality that should reveal hormetic effects.     

Degradation of pentachlorophenol by pure and mixed cultures in two different soils

GOAL, SCOPE AND BACKGROUND: Pentachlorophenol (PCP) is the second highest volume pesticide used in the United States. It is a mutagenic compound whose exposure poses significant health effects, One of the most desirable, environmentally friendly treatment methods is bioremediation. For soil-based contamination, the effectiveness of bioremediation will also be affected by the presence of an active indigenous population, sorption of the contaminant onto the soil, and environmental parameters. METHODS: Two pure strains and their mixed culture were used to evaluate PCP biodegradation in two different field soils, Columbia (CO) and New Mexico (NM). Biostimulation of the indigenous microbes was evaluated by adding nutrients. The efficiency of adding bacteria strains (bioaugmentation) for degrading PCP was determined with Arthrobacter sp., Flavobacterium sp. and a 50:50 mixture of the two bacteria strains. RESULTS: In CO soil, only 24%, 12% and 25% of the initial PCP concentration were degraded by Flavobacterium sp., Arthrobacter sp. and mixed culture, respectively. Arthrobacter sp. was used in NM soil with two initial concentrations and achieved degradation efficiencies of 57% and 61% for 361 and 95 mg kg- concentrations, respectively. Discussion. Analysis via statistical methods showed that the bacteria had different efficiencies on PCP degradation in each soil. 2 CONCLUSIONS: All bacteria catalyzed a higher PCP degradation when present in NM soil. Second, Flavobacterium sp. degraded more PCP than Arthrobacter sp. in CO soil. The mixed culture achieved the highest degradation efficiency regardless of the initial concentration or soil origin. RECOMMENDATIONS AND PERSPECTIVES: The effect of the soil properties, such as the soil organic matter (SOM) on PCP biodegradation should be investigated. Future work can also investigate the effect of aging time on biodegradation.