Forecasting of cyanobacterial density in Torrão reservoir using artificial neural networks

The ability of general regression neural networks (GRNN) to forecast the density of cyanobacteria in the Torr?o reservoir (Tamega river, Portugal), in a period of 15 days, based on three years of collected physical and chemical data, was assessed. Several models were developed and 176 were selected based on their correlation values for the verification series. A time lag of 11 was used, equivalent to one sample (periods of 15 days in the summer and 30 days in the winter). Several combinations of the series were used. Input and output data collected from three depths of the reservoir were applied (surface, euphotic zone limit and bottom). The model that presented a higher average correlation value presented the correlations 0.991; 0.843; 0.978 for training, verification and test series. This model had the three series independent in time: first test series, then verification series and, finally, training series. Only six input variables were considered significant to the performance of this model: ammonia, phosphates, dissolved oxygen, water temperature, pH and water evaporation, physical and chemical parameters referring to the three depths of the reservoir. These variables are common to the next four best models produced and, although these included other input variables, their performance was not better than the selected best model.     

Pre-industrial sediment concentrations of metals: insights from the Venice lagoon (Italy)

Environmental Science and Pollution Research - This study investigated the occurrence of selected metals and metalloids (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in radio-dated sediment cores from a coastal...     

The effect of changes in surface wettability on two-phase saturated flow in horizontal replicas of single natural fractures

By using translucent epoxy replicas of natural single fractures, it is possible to optically measure aperture distribution and directly observe NAPL flow. However, detailed characterization of epoxy reveals that it is not a sufficiently good analogue to natural rock for many two-phase flow studies. The surface properties of epoxy, which is hydrophobic, are quite unlike those of natural rock, which is generally assumed to be hydrophilic. Different surface wettabilities result in dramatically different two-phase flow behavior and residual distributions. In hydrophobic replicas, the NAPL flows in well-developed channels, displacing water and filling all of the pore space. In hydrophilic replicas, the invading NAPL is confined to the largest aperture pathways and flow frequently occurs in pulses, with no limited or no stable channel development, resulting in isolated blobs with limited accessible surface area. The pulsing and channel abandonment behaviors described are significantly different from the piston-flow frequently assumed in current modeling practice. In addition, NAPL never achieved total saturation in hydrophilic models, indicating that significantly more than a monolayer of water was bound to the model surface. Despite typically only 60-80% NAPL saturation, there was generally good agreement between theoretically calculated Young-Laplace aperture invasion boundaries and the observed minimum apertures invaded. The key to determining whether surface wettability is negligible, or not, lies in accurate characterization of the contaminant-geologic media system under study. As long as the triple-point contact angle of the system is low (<20 degrees), the assumption of perfect water wettability is not a bad one.     

Plastic ingestion by harbour porpoises <Emphasis Type="Italic">Phocoena phocoena</Emphasis> in the Netherlands: Establishing a standardised method

Stomach contents of harbour porpoises (Phocoena phocoena) collected in the Netherlands between 2003 and 2013 were inspected for the presence of plastic and other man-made litter. In 654 stomach samples the frequency of occurrence of plastic litter was 7% with less than 0.5% additional presence of non-synthetic man-made litter. However, we show that when a dedicated standard protocol for the detection of litter is followed, a considerably higher percentage (15% of 81 harbour porpoise stomachs from the period 2010–2013) contained plastic litter. Results thus strongly depended on methods used and time period considered. Occurrence of litter in the stomach was correlated to the presence of other non-food remains like stones, shells, bog-wood, etc., suggesting that litter was often ingested accidentally when the animals foraged close to the bottom. Most items were small and were not considered to have had a major health impact. No evident differences in ingestion were found between sexes or age groups, with the exception that neonates contained no litter. Polyethylene and polypropylene were the most common plastic types encountered. Compared to earlier literature on the harbour porpoise and related species, our results suggest higher levels of ingestion of litter. This is largely due to the lack of dedicated protocols to investigate marine litter ingestion in previous studies. Still, the low frequency of ingestion, and minor number and mass of litter items found in harbour porpoises in the relatively polluted southern North Sea indicates that the species is not a strong candidate for annual monitoring of marine litter trends under the EU marine strategy framework directive. However, for longer-term comparisons and regional differences, with proper dedicated protocols applied, the harbour porpoise has specific use in quantifying litter presence in the, for that specific objective, poorly studied benthic marine habitat.     

Source apportionment of settleable particles in an impacted urban and industrialized region in Brazil

Environmental Science and Pollution Research - Settleable particulate matter (SPM), especially coarser particles with diameters greater than 10&nbsp;μm, has been found culprit of high...     

Newborns and low to moderate prenatal environmental lead exposure: might fathers be the key?

This study is part of the BioMadrid Project, a bio-monitoring study designed to assess pollutants in the environment surrounding children born in the Madrid region. Our aim in this report is to evaluate the association between prenatal lead exposure and fetal development using three biological samples (maternal and paternal blood lead at around 34 weeks of gestation as well as cord blood lead levels), three biomarkers of effect in cord blood peripheral lymphocytes (micronucleus in binucleated cells, nucleoplasmic bridges, and nuclear buds), and different anthropometrical characteristics at birth. Maternal and cord blood lead were not associated with newborn measurements or genotoxicity biomarkers. In contrast, increases in father blood lead were coupled with lower weight (mean difference (MD), ?110.8 g; 95 % confidence intervals (95%CI), ?235.6 to 6.00; p?<?0.10) and shorter abdominal (MD, ?0.81 cm; 95%CI, ?1.64 to 0.00; p?<?0.05) and cephalic (MD, ?0.32 cm; 95%CI, ?0.65 to 0.00; p?<?0.05) circumferences at birth as well as with the presence of nucleoplasmic bridges (odds ratio, 1.03; 95%CI, 1.00 to 1.06; p?<?0.05) and nuclear buds (odds ratio, 1.02; 95%CI, 0.99 to 1.04; p?<?0.10). These associations were mainly confined to female babies, in whom paternal lead was also inversely associated with length. Our results support the hypothesis that paternal lead exposure may be affecting the development of newborns.     

Selenium,total mercury and methylmercury in sardine: Study of molar ratio and protective effect on the diet

The purpose of this work was to evaluate the risk-benefit associated with canned sardine consumption, considering the selenium, the mercury and the methylmercury contents and the Se:Hg molar ratio and the Se-health benefit value (HBV) index. In this study, 63 canned sardine samples were purchased worldwide and for the determination of selenium and mercury species, the inductively coupled plasma optical emission spectrometry and thermal decomposition and amalgamation atomic absorption spectrometry were employed. The mean results obtained for the Brazilian samples varied between 12.6 and 65.5?μg kg^?1 for Hg; <3.7 and 45.4?μg kg^?1 for methylmercury; 310 and 1370?μg kg^?1 for Se. The MeHg/Hg ratio showed that the most toxic forms of Hg (MeHg) is predominant in 52 and 39% of the Brazilian samples conserved in tomato sauce and in oil, respectively. Nevertheless, the Se-HBV index and the Hg:Se and Se:Hg molar ratios indicated that the selenium content in canned sardine samples is enough to provide a protective effect on the Hg species.     

‘End to end’ planktonic trophic web and its implications for the mussel farms in the Mar Piccolo of Taranto (Ionian Sea,Italy)

The Mar Piccolo is a semi-enclosed basin subject to different natural and anthropogenic stressors. In order to better understand plankton dynamics and preferential carbon pathways within the planktonic trophic web, an integrated approach was adopted for the first time by examining all trophic levels (virioplankton, the heterotrophic and phototrophic fractions of pico-, nano- and microplankton, as well as mesozooplankton). Plankton abundance and biomass were investigated during four surveys in the period 2013–2014. Beside unveiling the dynamics of different plankton groups in the Mar Piccolo, the study revealed that high portion of the plankton carbon (C) pool was constituted by small-sized (<2 μm) planktonic fractions. The prevalence of small-sized species within micro- and mesozooplankton communities was observed as well. The succession of planktonic communities was clearly driven by the seasonality, i.e. by the nutrient availability and physical features of the water column. Our hypothesis is that beside the ‘bottom-up’ control and the grazing pressure, inferred from the C pools of different plankton groups, the presence of mussel farms in the Mar Piccolo exerts a profound impact on plankton communities, not only due to the important sequestration of the plankton biomass but also by strongly influencing its structure.     

Ecotoxicological effects of sediments from Mar Piccolo,South Italy: toxicity testing with organisms from different trophic levels

The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.     

Cellular damages in the Allium cepa test system, caused by BTEX mixture prior and after biodegradation process

Petroleum and derivatives have been considered one of the main environmental contaminants. Among petroleum derivatives, the volatile organic compounds benzene, toluene, ethylbenzene and xylene (BTEX) represent a major concern due to their toxicity and easy accumulation in groundwater. Biodegradation methods seem to be suitable tools for the clean-up of BTEX contaminants from groundwater. Genotoxic and mutagenic potential of BTEX prior and after biodegradation process was evaluated through analyses of chromosomal aberrations and MN test in meristematic and F₁ root cells using the Allium cepa test system. Seeds of A. cepa were germinated into five concentrations of BTEX, non-biodegraded and biodegraded, in ultra-pure water (negative control), in MMS 4 × 10⁻⁴ M (positive control) and in culture medium used in the biodegradation (blank biodegradation control). Results showed a significant frequency of both chromosomal and nuclear aberrations. The micronucleus (MN) frequency in meristematic cells was significant for most of tested samples. However, MN was not present in significant levels in the F₁ cells, suggesting that there was no permanent damage for the meristematic cell. The BTEX effects were significantly reduced in the biodegraded samples when compared to the respective non-biodegraded concentrations. Therefore, in this study, the biodegradation process showed to be a reliable and effective alternative to treat BTEX-contaminated waters. Based on our results and available data, the BTEX toxicity could also be related to a synergistic effect of its compounds.