Assessment of water quality in the Alqueva Reservoir (Portugal) using bioassays

Background, aim, and scope  

Alqueva Reservoir is the biggest artificial freshwater reservoir in Europe and is an important water supply for human and agricultural consumption in the Alentejo region (Portugal). Pollution can impair environmental and human health status, and to assure water quality and ecological balance, it is crucial to frequently monitor water supplies. In this study, we used an ecotoxicological test battery to identify the potential toxicity of water from this reservoir.     

Biochemical responses of the marine mussel Mytilus galloprovincialis to petrochemical environmental contamination along the North-western coast of Portugal

Following the development of urban and industrial centres petrochemical products have become a widespread class of contaminants. The aim of this study was to investigate the effects of petrochemical contamination in wild populations of mussels (Mytilus galloprovincialis) along the NW Atlantic coast of Portugal by applying antioxidant and energetic metabolism parameters as biomarkers. For that, mussels were collected at five sampling sites presenting different petrochemical contamination levels. To evaluate the mussels' antioxidant status, enzymatic activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione S-transferases, as well as glutathione redox status were evaluated in gills and digestive glands of mussels collected from the selected sites. Lipid peroxidation was determined in the same tissues to quantify cellular oxidative damage. Furthermore, to investigate how energetic processes may respond to these contaminants, the activity of NADP(+)-dependent isocitrate dehydrogenase was determined in mussels' digestive glands, and octopine dehydrogenase was determined in mussels' posterior adductor muscle. Furthermore, the concentrations of aliphatic hydrocarbons, unresolved complex mixture and polycyclic aromatic hydrocarbons (PAHs) were quantified in mussels' tissue, and abiotic parameters were quantified in water samples collected at each site. Several biomarkers showed statistically significant differences among sampling sites. The redundancy analysis (RDA) used to perform the integrated analysis of the data showed a clear separation of the sampling sites in three different assemblages, which are in agreement with the PAHs levels found in mussels tissues. In addition, the RDA indicated that some of the selected biomarkers may be influenced by abiotic parameters (e.g. salinity, pH, nitrates and ammonia). The approach selected for this study seems to be suitable for monitoring petrochemical contamination.     

Mandarin peelings: the best carbon source to produce laccase by static cultures of Trametes pubescens

In the present study, we investigated the effect of different carbon sources (glucose, glycerol and ground mandarin peelings) on laccase production by Trametes pubescens grown on stainless steel sponges under static conditions. The cultures with ground mandarin peelings gave the highest laccase activities, showing values of about 100 U l(-1). This is a very interesting result, since mandarin peelings are common agricultural wastes in some regions such as Mediterranean and Asiatic countries. Therefore, their reutilisation, besides reducing medium cost, also helps to solve the pollution problems caused by their disposal. Also, we studied the effect of supplementing the culture medium with different potential laccase-inducing compounds (ABTS, Tween 20, soya oil, Malaquite Green, Cu(2+), tannic acid) on laccase production. Soya oil was the best inducer of laccase activities, attaining values 4-fold higher than those obtained in the reference cultures.     

Molecular biodiversity. Case study: Porifera (sponges)

Biological diversity--or biodiversity--is the term given to the variety of life on Earth and the natural patterns it forms. The biodiversity we see today is the fruit of billions of years of evolution, shaped by natural processes and, increasingly, by the influence of humans. It forms the web of life of which we are an integral part and upon which we so fully depend. The research on molecular biodiversity tries to lay the scientific foundation of a rational conservation policy that has its roots in various disciplines including systematics/taxonomy (species richness), present day ecology (diversity of ecological systems), and functional genetics (genetic diversity). The results of ongoing genome analyses (genome projects and expressed sequence tag projects) and the achievements of molecular evolution may allow us not only to quantitate the diversity of the present biota but also to extrapolate to their diversification in the future. A link between biodiversity and genomics/molecular evolution will create a platform which we hope may facilitate a sustainable management of organismic life and ensure its exploitation for human benefit. In the present review we outline possible strategies, using the Porifera (sponges) as a prominent example. On the basis of solid taxonomy and ecological data, the high value of this phylum for human application becomes obvious, especially with regard to the field of chemical ecology and the desire to find novel potential drugs for clinical use. In addition, the benefit of trying to make sense of molecular biodiversity using sponges as an example can be seen in the fact that the study of these animals, which are "living fossils", gives us a good insight into the history of our planet, especially with respect to the evolution of Metazoa.     

Valuing water quality in China: purpose, approach and policy

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Fungi and nematodes occurring in different composts used in Uruguayan agriculture

Forty three thermophilic, thermotolerant and mesophilic fungal species and nematodes from five trophic groups were found in four compost types. Aspergillus fumigatus and A. niger were the most frequent species. Plant pathogenic fungi viz. Fusarium oxysporum, F. acuminatum, F. nygamai and F. solani were found in some of the composts in low frequency. The most abundant species of nematode corresponded to bacterivores. Tylenchus, a phytophagous nematode was scarcely found.     

Spatio-temporal variability in fatty acid trophic biomarkers in stomach contents and muscle of Iberian sardine (<Emphasis Type="Italic">Sardina pilchardus</Emphasis>) and its relationship with spawning

Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative contribution to dietary carbon made by different prey types for fish from two areas off Portugal. The effect of the FA content of the diet on sardine muscle FA composition was also studied, aiming at (1) analysing if FA biomarkers can be used as a complementary technique for the study of sardine diet and (2) to relate spatial and temporal variations of prey FA content with sardine condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations of n-3 polyunsaturated FA, namely eicosapentaenoic acid [EPA, 20:5n-3] and linolenic acid 18:3n-3, being significantly higher in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was also detected in their muscle composition, specifically for EPA, and the eicosapentaenoic/docosahexaenoic acid and (n-3)/(n-6) ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines accumulate high concentrations of FAs during the resting stage of reproduction when the feeding intensity is similar or lower to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish body composition, namely on the accumulation of essential FAs, which can have a strong impact on reproduction success for this species.     

Laboratory study on the leaching potential of spent alkaline batteries

Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests were extended to another leaching step where leachant percolated the columns in a closed loop process.Leachate solutions were periodically sampled and pH, conductivity, density, redox potential, sulphates, chlorides and heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were determined in the samples.The results showed that the total amount of substances leached in tests with cross-cut batteries was higher than with entire ones; zinc and sulphates were the substances found the most in the leachate solutions. In general, the amount of substances dissolved in open circuit is higher than in closed loop due to the effect of solution saturation and the absence of fresh solution addition.Results were compared with metal contents in the batteries and with legal limits for acceptance in landfill (Decision 2003/33/CE and Decree-Law 152/2002). None of the metals were meaningfully dissolved comparatively to its content in the batteries, except Hg. Despite the differences in the experiment procedure used and the one stated in the legislation (mixing, contact time and granulometry), the comparison of results obtained with cross-cut batteries using deionized water with legal limits showed that batteries studied could be considered hazardous waste.