Properties of slate mining wastes incubated with grape marc compost under laboratory conditions

The effect of the addition of spent grape marc compost (GMC) and vermicompost (GMV) as amendments to slate mining wastes was evaluated in a laboratory incubation experiment. Mixtures of slate processing fines (SPF), with three doses of each amendment (4%, 8% and 16% compost, dry weight), plus a control were incubated at 25 degrees C in the laboratory for 90 days. The changes in the chemical and biological properties of the mixtures (pH, total C, total N, inorganic N, available nutrients, microbial biomass carbon and dehydrogenase activity) were investigated during the incubation period, and once it was finished, the phytotoxicity of the mixtures was determined by the germination of Lolium multiflorum Lam. seeds. The addition of the amendments significantly increased the nutrient concentrations of the SPF and enhanced biological activity by increasing microbial biomass and enzymatic activity. Results improved with higher doses; within the composts, GMV showed a better performance than GMC. These results prove the suitability of grape marc-derived amendments for the biochemical amelioration of mining wastes, and highlight the benefits of organic amendment in restoration projects.     

Nonylphenol algal bioaccumulation and its effect through the trophic chain

Nonylphenol is a metabolic intermediate from the microbial transformation of detergents used worldwide. While nonylphenol shows some acute toxicity, it is also able to mimic important hormones resulting in the disruption of several processes by interfering with the signals that control the overall physiology of the organism. The effect of the pollutant nonylphenol (NP) through the trophic chain was studied. Microalgae Isochrysis galbana was able to bioconcentrate NP 6940 times, where 77% of initial NP (100microgl(-1)) is accumulated intracellularly after 1-h incubation. Crustacean Artemia fransiscana showed 25% higher growth when fed with NP-rich algae. However, Artemia metabolized almost all NP ingested and only traces of NP could be found in the organism, eliminating future NP effects. Zebrafish (Brachydanio rerio) were affected by the presence of 171microgg(-1) of NP in the diet, showing higher levels of the hormone vitellogenin and lower levels of cytochrome P450 activity. These results showed that organisms placed in the first level of trophic chain are able to significantly bioconcentrate the pollutant and endocrine disruptor NP. These grassed organisms affect the growth of crustacean. Moreover, the organisms placed on the top of some trophic chains, such as fish, could be affected by the presence of NP in their food, in both the hormone levels and metabolic enzymes. This work shows that the environmental presence of NP should be considered as a risk for the organisms living in an ecosystem.     

Pesticide residues in dried table grapes from the Aegean region of Turkey

Dried grapes make the ideal low-calorie snack. The formation of gray mold during the drying of the grapes can severely decrease production. Pesticides and fungicides are applied to prevent losses due to pests and mold. Dried grapes from 99 farms in the Aegean region were sampled for pesticide residues. Of the 26 pesticides analyzed for, chlorpyrifos methyl, chlorpyrifos ethyl, deltamethrin, lambda-cyolathrin, dichlofluanid, iprodione, and procymidone were detected in the dried grapes. Only seven samples contained residues above the maximum residue limit. It is important to note that pesticide residues were only present in samples originating from vineyards using conventional farming practices.     

Exploring the utility of <Emphasis Type="Italic">Posidonia oceanica</Emphasis> chlorophyll fluorescence as an indicator of water quality within the European Water Framework Directive

The European Water Framework Directive commits partner countries to evolve uniform protocols for monitoring the environmental condition of natural water bodies, crucially integrating biological and ecological criteria from the associated ecosystems. This has encouraged considerable research on the development of bioindicator-based systems of water quality monitoring. A critical step towards this end is providing evidence that the proposed bioindicator system adequately reflects the human pressures to which a specific water body is submitted. Here we investigate the utility of pulse-amplitude-modulated (PAM) fluorometry, a fast, non-destructive and increasingly popular bioindicator-based method, in assessing water quality based on the widespread Mediterranean seagrass Posidonia oceanica, an important constituent of submersed benthic vegetation. Specifically, we evaluated the ability of PAM to discriminate between sites along a pre-established gradient of anthropogenic pressures and the consistency and reliability of PAM parameters across spatial scales. Our results show that the maximum quantum yield (Fv/Fm), representing the structural photosynthetic efficiency of the plant, responds significantly to the degree of site-level anthropogenic pressure. However, Fv/Fm values in our study increased with increasing pressure, in striking contrast with other studies that report declines in Fv/Fm values with increasing stress. A potential explanation for this discrepancy is that our study sites were influenced by multiple diffuse stressors (characteristic of most coastal waters) that could potentially interact with each other to influence Fv/Fm values in often unpredictable ways. The photosynthetic variables calculated from rapid light curves (ETR_max, maximum electron transport rate; α, initial slope of the curve; I _k, saturating irradiance), which represent an instant picture of the photosynthetic activity of the plant, were unable to clearly discriminate between sites subject to different anthropogenic pressures due to considerable small-scale variability. Taken together, these results suggest that even though PAM fluorometry may be a good candidate tool for monitoring water bodies in terms of costs and applicability, considerably more needs to be understood about how its parameters respond to real-world stressors, particularly when they act in concert with each other. With our present understanding of seagrass photosynthetic responses to anthropogenic stress, it would be ill advised to employ PAM as anything but a complementary tool to validate environmental stress derived with other, more robust methodologies.     

Assessing dam implementation impact on threatened carnivores: the case of Alqueva in SE Portugal

Large dam construction in water deficient areas is a management decision often controversial. Besides providing water storage, economical benefits, and a source of renewable energy, the construction and flooding caused by large dams cause disruptions in natural systems. We monitored the pre- and post-Alqueva dam impacts on the threatened carnivore species (polecat, otter, wildcat and Iberian lynx) populations in SE Portugal, and assessed which factors mostly contribute to post-dam distribution. Major short term impacts of large dams are: (1) increase in accessibility and human presence; (2) movement of heavy machinery and dam-workers; (3) deforestation with habitat loss and fragmentation; (4) change from lotic to lentic system; (5) lower prey availability and harsher capture; and (6) changes in land use adjacent to the reservoir. Thus, the response to those impacts can be predicted as a decline of polecat, wildcat and lynx distribution ranges, and a recovery of the otter from the severe short term impacts. Our results corroborate this hypothesis for all the species, especially during deforestation/early flooding. Otter's distribution range increased in the phase of greater impact, with a subsequent decrease with flooding. Our results suggest carnivores used "escape" areas with favourable habitat and prey conditions, however, the areas with higher probability of species presence decreased by two fold showing a drastic range reduction. To ensure populations' survival of these charismatic threatened carnivore populations of Mediterranean landscapes of south-east Portugal, we propose continuing the monitoring program and the development of a conservation program for the subsisting areas of optimal and suboptimal habitats.     

Leachable 226Ra in Philippine phosphogypsum and its implication in groundwater contamination in Isabel, Leyte, Philippines

Phosphogypsum (PG), the major waste material in phosphate fertilizer processing, has been known to contain enhanced levels of naturally-occurring radionuclides especially (226)Ra.The lack of radioactivity data regarding Philippine phosphogypsum and its environmental behavior in the Philippine setting has brought concern on possible contamination of groundwater beneath the phosphogypsum ponds in Isabel, Leyte, Philippines. The radioactivity of Philippine phosphogypsum was determined and the leaching of (226)Ra from phosphogypsum and through local soil was quantified. Level of (226)Ra in groundwater samples in Isabel, Leyte, Philippines was also quantified to address the primary concern. It was found that the (226)Ra activity in Philippine phosphogypsum is distributed in a wide range from 91.5 to 935 Bq/kg. As much as 5% of (226)Ra can be leached from Philippine PG with deionized water. In vitro soil leach experiments suggest that the soil in the phosphate fertilizer plant area would be able to deter the intrusion of (226)Ra into the water table. Compared to reported values of natural groundwater levels of (226)Ra, the concentration of this radionuclide in Isabel, Leyte groundwater suggest that there is no (226)Ra intrusion brought about by the presence of phosphogypsum ponds in the area.     

Using the Sediment Quality Triad to characterize baseline conditions in the Anacostia River, Washington, DC, USA

The Sediment Quality Triad (SQT) consists of complementary measures of sediment chemistry, benthic community structure, and sediment toxicity. We applied the SQT at 20 stations in the tidal portion of the Anacostia River from Bladensburg, MD to Washington, DC to establish a baseline of conditions to evaluate the effects of management actions. Sediment toxicity was assessed using 10-day survival and growth tests with the freshwater amphipod, Hyalella azteca and the midge, Chironomus dilutus. Triplicate grabs were taken at each station for benthic community analysis and the Benthic Index of Biotic Integrity (B-IBI) was used to interpret the data. Only one station, #92, exhibited toxicity related to sediment contamination. Sediments from this station significantly inhibited growth of both test species, had the highest concentrations of contaminants, and had a degraded benthic community, indicated by a B-IBI of less than 3. Additional sediment from this station was tested and sediment toxicity identification evaluation (TIE) procedures tentatively characterized organic compounds as the cause of toxicity. Overall, forty percent of the stations were classified as degraded by the B-IBI. However, qualitative and quantitative comparisons with sediment quality benchmarks indicated no clear relationship between benthic community health and contaminant concentrations. This study provides a baseline for assessing the effectiveness of management actions in the Anacostia River.     

Evaluation of spatial and temporal variations in marine sediments quality using multivariate statistical techniques

Spatial and temporal variations of sediment quality in Matanzas Bay (Cuba) were studied by determining a total of 12 variables (Zn, Cu, Pb, As, Ni, Co, Al, Fe, Mn, V, CO₃ ^2?, and total hydrocarbons (THC). Surface sediments were collected, annually, at eight stations during 2005–2008. Multivariate statistical techniques, such as principal component (PCA), cluster (CA), and lineal discriminant (LDA) analyses were applied for identification of the most significant variables influencing the environmental quality of sediments. Heavy metals (Zn, Cu, Pb, V, and As) and THC were the most significant species contributing to sediment quality variations during the sampling period. Concentrations of V and As were determined in sediments of this ecosystem for the first time. The variation of sediment environmental quality with the sampling period and the differentiation of samples in three groups along the bay were obtained. The usefulness of the multivariate statistical techniques employed for the environmental interpretation of a limited dataset was confirmed.     

Does Engagement in Advocacy Hurt the Credibility of Scientists? Results from a Randomized National Survey Experiment

It is often assumed that issue advocacy will compromise the credibility of scientists. We conducted a randomized controlled experiment to test public reactions to six different advocacy statements made by a scientist—ranging from a purely informational statement to an endorsement of specific policies. We found that perceived credibility of the communicating scientist was uniformly high in five of the six message conditions, suffering only when he advocated for a specific policy—building more nuclear power plants (although credibility did not suffer when advocating for a different specific policy—carbon dioxide limits at power plants). We also found no significant differences in trust in the broader climate science community between the six message conditions. Our results suggest that climate scientists who wish to engage in certain forms of advocacy have considerable latitude to do so without risking harm to their credibility, or the credibility of the scientific community.