Validation of isotope signatures in sediments affected by anthropogenic inputs from uranium series radionuclides

This paper aims to show the usefulness of 226Ra/228Ra activity ratios and confirm the possibility of using 230Th/232Th activity ratios as chronological markers in sediment cores from an estuarine system strongly contaminated by discharges from non-nuclear industries (fertiliser plants). The validation was carried out using an independent, well-established dating technique based on the analysis of the 137Cs fallout profile, which comprises the same time interval as that covered by both isotope ratios. The advantage of using the 226Ra/228Ra activity ratio profile instead of the Th-isotope profile is that determination can be accomplished with a non-destructive, simpler and less time-consuming technique, because both Ra isotopes can be determined by gamma-ray spectrometry.     

Postfire Regeneration in <Emphasis Type="Italic">Pinus pinea</Emphasis> L. and <Emphasis Type="Italic">Pinus pinaster</Emphasis> Aiton in Andalucia (Spain)

The objective of this study was to examine postfire regeneration of tree, shrub, and dwarf shrub species, in relation to levels of damage in four planted pine forests (Pinus pinea, Pinus pinaster) in Andalusia. A prefire vegetation map was used for detailing species composition, vertical structure, and density and another for detailing the extent and intensity of fire damage. Between 3 and 7 years after the fires, an inventory was made of the vegetation in each area, using the step-point method. The information thus obtained was used to determine the amount of cover in the dwarf/shrub and tree layers, the frequency of species in each of the layers, floristic richness, and diversity (Shannon index). The botanical composition of the dwarf and shrub layer was analyzed using TWINSPAN. Variables were poorly correlated with level of fire damage, which suggests that the forests in this study followed the autosuccession model. Because of the artificial origin or seminatural condition, regeneration of the dominant tree species is poor, and it seems unlikely that forests will recover to their prefire state. Therefore action is recommended to restore these ecosystems.     

Metal Pollution in the Environment of Minas Gerais State – Brazil

Intense mining activities in Minas Gerais State – Brazil brings out tons of waste to the environment. Considerable concentrations of toxic elements penetrate the soil, ground waters and rivers. This endangers the environment quality not only in the surrounding areas but also in ichthyofauna and in more distant areas of cattle raising and agricultural activities. After seasonal floods, veterinary clinic studies have shown that most animals raised in this region are affected by symptomatologic nervous diseases, still not clearly diagnosed, which suggests intoxication. These pathologies are mostly noted after floods. Instrumental Neutron Activation Analysis was applied to determine Al, As, Au, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, La, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Th and Zn in environmental samples. The obtained results show that the water and sediment contaminated with heavy metals and toxic elements from the Das Velhas River upstream basin, the mining region, carry contamination to the ichthyofauna and farming region within a distance of approximately 400 km.     

Copepods and Larvae of Nematodes Parasiting the White Mullet Mugil Curema (Valenciennes, 1836): Indicators of Anthropogenic Impacts in Tropical Coastal Lagoons?

The relationship between parasites and environmental stress were studied in two tropical coastal lagoons of Northwest Mexico: Urias estuary (highly polluted) and Teacapan estuary (slightly polluted). Metazoan parasites were examined in 292 white mullet (Mugil curema) specimens collected bimonthly during a year from both systems. Haliotrema mugilinus, Metamicrocotyla macracantha, Ergasilus sp., Caligus sp., Holobomolochus sp., and Lernaeopodidae were found in gills, while Contracaecum sp. larvae III was found liver, hepatic portal vein and kidneys. Ecological indices were influenced by the slightly higher number of parasitic species in Urias compared to Teacapan, as well as the clear dominance of two species: Ergasilus sp. and Contracaecum sp. in both systems. In fact, Ergasilus sp. showed considerably higher abundance in Urias, possibly indicating that its success was a result of adverse conditions affecting the host, while Contracaecum sp showed higher abundances in Teacapan, suggesting that the environmental conditions occurring in Urias could have produced negative impacts on the nematode's infective potential.     

Cell-based assays as an alternative for the study of aquatic toxicity of pharmaceuticals

An increasing number and amount of pharmaceuticals for human and veterinary use currently reach the aquatic environment, and the determination of their effects on aquatic organisms becomes of major importance. The 96-h fish lethal test is one of the conventional assays required for environmental hazardous assessment, but it is extremely time-consuming and costly, and it raises ethical concerns. In a broad study, we compared the ability of cell-based assays to detect, in absolute terms, lethal toxicity in fish due to pharmaceuticals in order to select sensitive cell lines to be posteriorly used as an alternative to fish testing. This study also explored the sensitivity of the rat cardiomyoblast H9c2(2-1) cell line and the suitability of the sulforhodamine B colorimetric assay regarding 15 pharmaceuticals belonging to 9 different therapeutic classes. The relation between in vivo and in vitro data was expressed as LC_50,96h/EC₅₀ ratios, and 66% of concordant data were attained. Accordingly, it was possible to conclude that cell-based assays could be considered a suitable alternative to fish lethal testing for pharmaceuticals, which, after validation, may dramatically reduce the number of fish required for environmental hazardous assessment. Several cell lines were selected as promising alternatives, but H9c2(2-1), HepG2, PLHC-1, and RTG-2 could be considered suitable starting cell types for further studies, as relevant results were obtained with low exposure times.

     

Occurrence of PCDD/Fs and dioxin-like PCBs in superficial sediment of Portuguese estuaries

Superficial sediments collected from seven estuarine systems located along the Portuguese coast were analyzed for 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), and 12 dioxin-like polychlorinated biphenyls (dl-PCBs). Total PCDD/F concentration ranged from 4.6 to 464 pg g^?1 dry weight (dw), while that of dl-PCBs varied from 26.6 to 8,693 pg g^?1 dw. In general, the highest PCDD/F and dl-PCB concentrations were associated with densely populated and industrially impacted areas. Additionally, PCDD/F revealed a predominance of octachlorodibenzodioxin (OCDD) to total PCDD/Fs, while PCB 118 was the major contributor to total dl-PCBs. This study provided a global perspective of the contamination status of Portuguese estuaries by dioxin-like compounds and allowed a comparison between the investigated systems and other systems worldwide. PCDD/F and dl-PCB levels found in the collected sediments were lower than those of highly impacted areas from different parts of the globe. Nevertheless, comparison with guidelines and quality standards from other countries indicated that some Portuguese estuarine areas with a high industrialization level present PCDD/F and dl-PCB concentrations in superficial sediment that may constitute a risk to aquatic organisms.     

Fuel from waste tyres and particulate matter emitted from the process

The interest in obtaining alternative fuels from waste sources and at the same time diminishing the impact of waste disposal has drawn attention to scrap tyres' carbon recovery. In order to thermally degrade used tyre rubber, a laboratory pyrolysis system was developed in this work. The installation devised focused on the production of liquid pyrolysates, where shredded rubber was supplied as the feedstock and nitrogen used as the carrier gas to provide an oxygen-free atmosphere. The variables affecting the performance of the process were investigated, including target temperature, heating rate and total residence time. Characterization of the volatile matter released was conducted by means of mass spectrometry to determine the composition of products, and particulate matter analysis to ascertain the aerosol content in the gas stream. The reproducibility of experiments, the influence of the temperature and time, and differences between the vapours before condensation and the exhaust gases are discussed. This work identified that the larger hydrocarbon fragments condense to constitute the oils, whereas the lighter molecules remain as non-condensable gases. This work also identified that the total number of nano-scale particles carried by the exhaust stream varies with temperature; significant changes in the composition of products and particle content were reported at approximately 400°C. The high number of nano-scale solid particulate matter present in the exhaust gases suggests that a thorough treatment for that stream would be required to avoid human health hazards.     

Organochlorine contaminants in different tissues from Platichthys flesus (Pisces,Pleuronectidea)

Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) are organic contaminants that tend to accumulate in fish. Estuaries are exposed to high anthropogenic activities, therefore tending to accumulate more contaminants than the adjacent coastal waters. Platichthys flesus, a fish with high economic value, was analysed for PCBs and HCB along its different age groups, in liver, gills, gonads and muscle. Younger fishes were caught in the estuary, whereas older fishes were caught in the adjacent coastal waters and acquired at Figueira da Foz Regional Office of Docapesca-Portos e Lotas, SA. Both contaminants concentrations follow the pattern: liver > gills > muscle. Hepatosomatic index had the lowest values in younger fishes and the highest values in older fishes. Condition factor values remain stable with age. Younger fishes had higher PCBs concentrations than the older fishes. In opposition HCB was only detected in fish from 3+ to 5+ and its concentration tended to increase with age. Overall P. flesus is considered safe for human intake.     

Phytomanagement of strongly acidic,saline eutrophic wetlands polluted by mine wastes: The influence of liming and Sarcocornia fruticosa on metals mobility

The aim of this study was to assess the effectiveness of combining liming and vegetation for the phytomanagement of strongly acidic, saline eutrophic wetlands polluted by mine wastes. Simulated soil profiles were constructed and four treatments were assayed: without liming + without plant, without liming + with plant, with liming + without plant and with liming + with plant. The plant species was the halophyte Sarcocornia fruticosa. Three horizons were differentiated: A (never under water), C1 (alternating flooding–drying conditions) and C2 (always under water). The soluble Cd, Cu, Mn, Pb and Zn concentrations were measured regularly for 18 weeks and a sequential extraction procedure was applied at the end of the experiment. Liming was effective (between ～70% and ～100%) in reducing the soluble Zn, Cu and Pb. In contrast, soluble Mn and Cd increased with liming, especially in the treatment with liming + with plant, where the concentrations were 2-fold higher than in the non-limed treatments. The amendment increased the contents of Zn, Mn and Cd bound to potentially-mobilisable soil fractions at the expense of the most-environmentally-inert fractions. Hence, the combined use of liming and vegetation may increase the long-term environmental risk of metals solubilisation.