Quantification of metallothionein in whole body gammarus locusta (crustacea: amphipoda) using differential pulse polarography

A polarographic method was optimised for the quantitative determination of metallothionein (MT) in whole body Gammarus locusta (Crustacea: Amphipoda). The identity of the MT-like proteins was examined using electrophoretic analysis (SDS-PAGE) and induction studies (water-borne exposures to copper). The MT-method was then used to examine changes in MT levels over the lifetime (juveniles, sub-adults and adults) of a laboratory population of G. locusta; copper (Cu) and zinc (Zn) body burden were also measured by flame atomic absorption spectrometry. MT was quantified by heat-denaturation of 30?000?g supernatants (to remove the bulk of non-MT proteins) followed by differential pulse polarography (DPP) to measure sulphydryl-group containing proteins. DPP proved to be a sensitive and reliable method to quantify heat-stable total sulphydryl-proteins. The majority of the latter was indicated to be MT from SDS-PAGE and induction studies. SDS-PAGE revealed a putative MT of 23?±?0.6?kDa app. mol. wt., consistent with the average size of dimeric MTs (10–20?kDa) found in several aquatic invertebrate species. Copper-exposure revealed parallel increases in the amounts of 23?kDa protein and total sulphydryl-proteins. Levels of whole body MT (rabbit pure MT as standard) range between 1.3 and 2.3?mg?g^?1 dry wt. over the lifetime of G. locusta. Sex-related changes in MT status were observed, the levels in females being 1.6 times higher than in males (p<0.05). Copper and Zn body content changed over the lifetime of G. locusta, the levels in juveniles (p>0.05) and sub-adults (p<0.05) being higher than in adults. It is concluded that the inclusion of MT in ecotoxicological studies with amphipod crustaceans require some caution with respect to the stages of moulting and/or sexual maturation of organisms, but this should not provide any major impediment in its use in metal pollution monitoring.     

Quantitative assessment of the differential coastal vulnerability associated to oil spills

The risk associated with a given hazard (natural or technological) generally results from the interaction between the hazard potential and the vulnerability. This paper is centred on the assessment of the vulnerability variable. A quantitative vulnerability assessment and mapping methodology is proposed, with two main specificities: (1) it is hazard- and spatially-centred (respectively, oil spills and coastal areas) and; (2) the spatial segregation level used is the municipality. Due to the geographic context of the Portuguese mainland coast, the proposed methodology was applied in an attempt to illustrate the spatial distribution and the degree of the vulnerability associated to oil spills for mainland Portugal coastal municipalities. A final map is presented together with other informative elements. Analysis and discussion of the results allows for the understanding that: (1) there is a very heterogeneous and differential distribution of the degree of vulnerability to oil spills along the Portuguese coastline; (2) the application of specific hazard-centred and spatially-centred vulnerability assessment methodologies, comprising multi-dimensional indicators (e.g., geographic, ecological, demographic, social and economic), produces more robust and realistic results, highlighted by a thorough and spatially detailed analysis; and (3) future research is required on vulnerability assessment in Portugal; along side, hazard potential assessment methodologies must also be developed in order to create a final risk profile, which can be an extremely useful tool in spatial planning and management.     

Microbiological monitoring of Ruditapes decussatus from Ria Formosa Lagoon (South of Portugal)

Ria Formosa Lagoon is the most important bivalve production region of the South Portuguese coast. However, the microbial contamination has been increasing in the northwest area of the lagoon. This study assesses the microbiological contamination of clams Ruditapes decussatus from the most contaminated area for 1 year period. Escherichia coli levels were weekly determined and related with variations in several environmental parameters: precipitation, atmospheric temperature, solar radiation, wind velocity, humidity and tide height. Highest E. coli levels in clams were associated with periods of heaviest rainfall and lowest temperature, mainly due to diffuse sources of faecal discharges. A seasonal trend was observed: microbial contamination in clams was lowest in summer, with highest temperatures, intense solar radiation and dry weather and higher in the remaining seasons, especially in winter due to the runoff of faecal contaminated waters. Several measurements not only to protect the quality of the lagoon, but also to protect public health were recommended. The most imperative will be to detect and extinguish the diffuse contamination sources. Otherwise it might be necessary to implement an interdiction period of bivalve harvesting after heavy rainfalls.     

Arsenic bioaccessibility in a gold mining area: a health risk assessment for children

High concentrations of total arsenic (As) have been measured in soils of gold mining areas of Brazil. However, bioaccessibility tests have not yet been conducted on those materials, which is essential for better health risk estimates. This study aimed at?evaluating As bioaccessibility in samples from a gold mining area located in Brazil and assessing children's exposure to As-contaminated materials. Samples were collected from different materials (a control and four As-contaminated soils/sediments) found in a gold mine area located in Paracatu (MG), Brazil. Total and bioaccessible As concentrations were determined for all samples. The control soil presented the lowest As concentrations, while all other materials contained high total As concentrations (up to 2,666?mg?kg(-1)) and low bioaccessible As percentage (<4.2%), indicating a low risk from exposure of resident children next to this area. The calculated dose of exposure indicated that, except for the pond tailings, in all other areas, the exposure route considering soil ingestion contributed at most to 9.7% of the maximum As allowed ingestion per day (0.3?μg?kg(-1) BW day(-1)).     

Modelling of the coastal defence scheme of Espinho, Portugal

The most recent intervention on the coastline of Espinho, located on the Portuguese West Atlantic coast, was part of the General Plan for Coastal Protection in 1980/81. As a result, two unusually large groins/headlands were built which were reinforced and enlarged in 1997, slightly changing their geometry and orientation. However, due to the decreased sediment supply from the north and the impact of energetic sea conditions common to the northwest coast of Portugal the coastal evolution has not developed as desired, although in general terms the initial expectations were fulfilled. The numerical modelling of the Espinho coastline using SMC software focused on both hydrodynamic and hydromorphological aspects. The purpose of this study is to analyse the most vulnerable areas of the Espinho seafront for current velocities and littoral drift, as well as to confirm the effectiveness of the two groins in terms of coastal protection. To achieve this, various simulations were performed, taking into account diverse sea conditions.     

DNA damage in oral epithelial cells of individuals chronically exposed to indoor radon (<Superscript>222</Superscript>Rn) in a hydrothermal area

Hydrothermal areas are potentially hazardous to humans as volcanic gases such as radon (²²²Rn) are continuously released from soil diffuse degassing. Exposure to radon is estimated to be the second leading cause of lung cancer, but little is known about radon health-associated risks in hydrothermal regions. This cross-sectional study was designed to evaluate the DNA damage in the buccal epithelial cells of individuals chronically exposed to indoor radon in a volcanic area (Furnas volcano, Azores, Portugal) with a hydrothermal system. Buccal epithelial cells were collected from 33 individuals inhabiting the hydrothermal area (Ribeira Quente village) and from 49 individuals inhabiting a non-hydrothermal area (Ponta Delgada city). Indoor radon was measured with Ramon 2.2 detectors. Chromosome damage was measured by micronucleus cytome assay, and RAPD-PCR was used as a complementary tool to evaluate DNA damage, using three 10-mer primers (D11, F1 and F12). Indoor radon concentration correlated positively with the frequency of micronucleated cells (r _s = 0.325, p = 0.003). Exposure to radon is a risk factor for the occurrence micronucleated cells in the inhabitants of the hydrothermal area (RR = 1.71; 95% CI, 1.2–2.4; p = 0.003). One RAPD-PCR primer (F12) produced differences in the banding pattern, a fact that can indicate its potential for detecting radon-induced specific genomic alterations. The observed association between chronic exposure to indoor radon and the occurrence of chromosome damage in human oral epithelial cells evidences the usefulness of biological surveillance to assess mutations involved in pre-carcinogenesis in hydrothermal areas, reinforcing the need for further studies with human populations living in these areas.     

Sulfate pollution: evidence for electrochemical production of persulfate by oxidizing sulfate released by the surfactant sodium dodecyl sulfate

Environmental Chemistry Letters - There is increasing concern about contamination by surfactants that are used to extract organic pollutants during remediation of polluted soils and aquifers. For...     

Molecular insight into the population structure of common and spotted dolphins inhabiting the pelagic waters of the Northeast Atlantic

Several cetacean species exhibit fine-scale population structure despite their high dispersal capacities and the apparent continuity of the marine environment. In dolphins, most studies have focused on coastal areas and continental margins, and they revealed differentiated populations within relatively small geographic areas, sometimes in conjunction with a specialisation for different habitats (ecotypes). We analysed the population genetic structure of short-beaked common dolphins (Delphinus delphis) and Atlantic spotted dolphins (Stenella frontalis) in the Azores and Madeira, the two most isolated archipelagos of the North Atlantic. The archipelago of the Azores is divided into three groups of islands and stands 900 km away from Madeira. It is not known whether individuals migrate between groups of islands and archipelagos, nor whether distinct ecotypes are present. These questions were investigated by genetic analyses of 343 biopsy samples collected on free-ranging dolphins. The analyses consisted in sequencing part of the mitochondrial hyper-variable region, screening up to 14 microsatellite loci, and molecular sexing. Results did not unravel any population structure at the scale of the study area. Lack of differentiation matches expectations for spotted dolphins, which are transient in both archipelagos, but not for common dolphins, which are present year-round in the Azores and potentially resident. Absence of genetic structure over hundreds and even thousands of kilometres implies the existence of gene flow over much larger distances than usually documented in small delphinids, which could be achieved through individual movements. This finding indicates that population structure in oceanic habitat differs from that observed in coastal habitat.     

Estimating the influence of overhead transmission power lines and landscape context on the density of little bustard Tetrax tetrax breeding populations

Collision with conductors and earth cables is a known impact generated by transmission power lines, however there is virtually no information on how these infrastructures might affect bird distribution in a landscape context. With this work we specifically hypothesise that transmission power lines may affect the occurrence of a threatened bird, the little bustard (Tetrax tetrax). To test this hypothesis we used a Stochastic Dynamic Methodology (StDM), analysing the effects of power lines in a landscape perspective and simulating population trends as a response to power line installation and habitat changes induced by agricultural shifts in southern Portugal. The data used in the dynamic model construction included relevant gradients of environmental conditions and was sampled during the breeding seasons of 2003-2006. Transmission power lines were significantly avoided by the little bustard and the developed StDM model showed that the distance to these utility structures is the most important factor determining breeding densities in sites with suitable habitat for the species, which possibly leads to displacement of populations and habitat fragmentation. The model simulations also provided the base to analyse the cumulative effects caused by the habitat degradation that can ultimately lead to the extinction of local populations. Within priority conservation sites, the dismantling of existing transmission lines should be considered whenever possible, in order to ensure adequate breeding habitat. The model is considered useful as an auxiliary tool to be used in environmental impact assessments, management and conservation studies.     

Recycling glass-polishing sludge and aluminum anodising sludge in polyurethane and cement composites: fire performance and mechanical properties

Journal of Material Cycles and Waste Management - This article aims to study the mechanical strength and fire resistance of polyurethane/cement (PuCem) composites containing glass sludge and sludge...