Heavy metal concentrations in molluscs from the Senegal coast

Bivalve molluscs from the Western coast of Senegal were sampled and measured for their cadmium, copper and zinc concentrations. This part of Africa has not been studied as regards heavy metal concentrations in the molluscs. The collected species are two small African bivalve molluscs, living in the sand: Cardita ajar and Dosinia isocardia; the African mussel Perna perna which is the only mussel of this genus in the Western coast of Africa and the oyster Crassostrea gasar, which lives in mangroves attached to the rhizophores, in the intertidal zone. C. gasar and C. ajar present higher cadmium concentrations, respectively 6.82+/-0.54 and 13.77+/-0.80 microg Cd/g (d.w.) than the two other species (D. isocardia: 3.88+/-0.31 microg/g and P. perna 2.37+/-0.22 microg/g. Copper and zinc concentrations are in the range of the published values for C. gasar and P. perna collected elsewhere in Africa. The results suggest that cadmium may be present in high concentrations in Senegalese waters where upwellings occur.     

Radioecological software package: an interactive computational system to simulate the behaviour of radionuclides in semi-natural environments

RSP (Radioecological Software Package) is an interactive support system that simulates the behaviour of radionuclides in semi-natural environments and the consequences on the population in terms of the external exposure. RSP consists of three modules: the first one, soil mobility, simulates the vertical transport of radionuclide in soil using the mathematical model RABES. The second module, soil -to-plant transfer, simulates the radionuclide soil-to-plant transfer factor reported in the literature. Soil properties, vegetation types and environmental conditions are taken into consideration in the simulation process. In the third module, dose assessment, the dose-rate factor in air at a height of 1 m above ground can be calculated for sources distributed in a slab of finite thickness dn sources which are exponentially distributed with depth. The calculations are performed using DAGES Model, a Monte Carlo algorithm developed to simulated the photon transport for the soil/air configuration. A free copy of RSP can be downloaded from the website: http://imasl-apat.unsl.edu.ar.     

Energy rating methodology for light-duty vehicles: geographical impact

The aim of this paper was to describe a new energy dependency score methodology and its consequent application to cars sold in twelve regions: Europe (EU-28) and eleven specific countries worldwide (Australia, Brazil, China, India, Japan, Norway, Portugal, Russia, Saudi Arabia, South Africa and USA). This methodology was developed as a potential tool to inform consumers of their choice impact on the country’s economy. This methodology is based on primary energy assessments and origins for each energy pathway associated with a gasoline-, diesel-, natural gas (used for H₂ production)- or electricity (balanced with country electricity mix)-powered vehicle. An energy dependency index was attributed to the best-case (100 % endogenous production) and worst-case (0 % endogenous production) scenarios and consequently weighted with vehicle fuel consumption. This enabled obtaining an energy dependency index (10–0). This index could be assigned to an environmental and social index to provide a sustainability index and therefore complement a road vehicle environmental rating system, providing a combined index rating. Internal combustion engine vehicles and hybrid vehicles (that have oil products as energy source) rate the lowest for almost all locations, with the exception of regions that are energy independent (Norway, Saudi Arabia or Russia). Electric vehicles rank higher when comparing to the other technologies analyzed for all locations in this study. The plug-in hybrid electric vehicle shows generally a rank in an intermediate place, except for Japan where it scores lower than all other technologies.     

Manganese toxicity in Drosophila melanogaster: extension of the life span by resveratrol

The effect of resveratrol was studied on the life span and motor activity of Drosophila melanogaster treated with manganese (Mn). Two days after emerging from the pupa, male wild type D. melanogaster were fed for 13 days with corn media containing 15?mM Mn. Thereafter, Drosophila were divided into six groups of 300 flies each: (1) the flies remained treated with Mn; (2) began treatment with 0.43?mM resveratrol (Mn-resveratrol group); (3) received no additional treatment (Mn-no treatment group); (4) simultaneously fed with Mn and resveratrol (Mn?+?resveratrol group). In addition, a control (5) with no treatment and another group (6) fed only with resveratrol after emerging from the pupa were included. All Mn-treated flies (group 1) were dead on the 25th day. The life span in the resveratrol group was 91?±?0.33 days (mean?±?S.E.M.) and in Mn-resveratrol flies was 83?±?2 days. These two values were significantly higher than those detected in the control (5) and Mn-no treatment (group 3) flies whose life span were 68?±?0.33 and 67?±?2.31 days, respectively. The Mn?+?resveratrol-fed flies had a markedly higher life span (31?±?1.53 days) than Mn-fed flies (23?±?0.88 days). In the flies that received Mn (Mn and Mn?+?resveratrol groups), the motor activity decreased significantly with respect to control (groups 5) and the Mn–resveratrol and resveratrol groups. In conclusion, resveratrol increased significantly the life span of Mn-treated D. melanogaster.     

Wave hydrodynamics around a multi-functional artificial reef at Leirosa

This paper describes an application of the Boussinesq-type COULWAVE model to study the wave hydrodynamics in the vicinity of a multi-functional artificial reef (MFAR). This reef is under investigation and consists of a supplementary protection solution for the Leirosa sand dune system located at South of Figueira da Foz, on the Portuguese West coast. Such installation near the coastline is expected to contribute to enhance the surfing conditions in the area, protect the sand dune system in the surroundings of Leirosa beach, and increase its environmental value. Numerical calculations with the COULWAVE model were performed for four test cases, considering two reef geometries (differing in the reef angle) and two incident wave conditions (storm condition and a common wave condition). Comparisons between the results obtained, in terms of wave heights and breaking line positions allow us to assess the influence of the reef on the hydrodynamics near the beach and around the reef. Moreover, the reef performance was analysed in terms of surfability and coastal protection. The surfability parameters (breaker height, Iribarren number and peel angle) were calculated for each test case using the numerical wave heights, wave directions and wave breaking positions. Comparisons of parameters allow characterizing the most appropriate configuration of the reef to improve the surfing conditions in the study area. A methodology based on numerical free surface elevations and horizontal velocity components was developed to calculate wave directions, since this is not a direct output of the COULWAVE model. Concerning coastal protection, analyses of the mean currents around the reef were used together with observations of the velocity cells near the shoreline as an indication of the sediment transport.     

The effect of cadmium on antioxidant responses and the susceptibility to oxidative stress in the hydrothermal vent mussel Bathymodiolus azoricus

Hydrothermal vents are a unique environment of extreme physical–chemical characteristics and biological species composition. Cd is a toxic non-essential metal present in high concentrations in the hydrothermal vent environment, contrary to those found in marine coastal areas. Cd toxicity has been related, among other things, with reactive oxygen species production, even though this is a non-redox metal. Bathymodiolus azoricus is a deep-sea Mytilid bivalve very common in the Mid Atlantic Ridge (MAR) hydrothermal vent fields and very little is known about the antioxidant defence system in this specie. Because lethal Cd concentration in B. azoricus is unknown, the aim of this study was to assess the effects of a Cd concentration higher than that found in the hydrothermal vents on oxidative stress biomarkers, such as antioxidant enzymes. Mussels were exposed to 100 μg l⁻¹ Cd during 24, 48 and 144 h, respectively, in a pressurized aquarium (IPOCAMP). Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx), total oxyradical scavenging capacity (TOSC), metallothionein (MT) and lipid peroxidation (LPO) were measured in the gills and mantle of B. azoricus. The results indicate that gills are first affected by Cd toxicity. This may be due to different physiological functions of the tissues and by the presence of thio and methanotrophic symbiotic bacteria in the gills. The SOD and CAT are inhibited during the first day of exposure in the gills, although TOSC and MT concentrations were the same in control and exposed mussels. In the mantle, enzymatic activation only occurred after 6 days, and no significant differences in MT concentrations were found in the control and exposed mussels during the first day, as observed in the gills.     

Potential toxicity of leachate from the municipal landfill in view of the possibility of their migration to the environment through infiltration into groundwater

Environmental Geochemistry and Health - Leachate from landfills is a product of complex biological and physicochemical processes occurring during waste storage. In the present study, the toxicity...     

Assessing species reintroduction sites based on future climate suitability for food resources

The reintroduction of a species that is extinct in the wild demands caution because reintroduction locations may be associated with threats, such as hunting, poor-quality habitat, and climate change. This is the case for Cyanopsitta spixii (Spix's Macaw), which has been extinct in the wild since 2000. The few living individuals were created in captivity and will be used in a reintroduction project within the species’ original distribution area, the Caatinga domain (Brazil). Because the occurrence records for this bird are old and inaccurate, we investigated the current and future environmental suitability of the 14 plant species used by C. spixii as resource. These plants are key elements for the long-term reestablishment of the species in the wild, so the use of models helps in the assessment of the effects of climate change on the availability of these resources for the species and informs selection of the best places for reintroduction. We based our models of environmental suitability on 19 bioclimatic variables and nine physical soil and topography variables. Climate projections were created for the present and for the year 2070 with an optimistic (SSP2-4.5) and a pessimistic (SSP5-8.5) climate scenario. Both future climate scenarios lead to a reduction in area of environmental suitability that overlapped for all the plant species: 33% reduction for SSP2-4.5 and 63% reduction for SSP5-8.5. If our projections materialize, climate change could thus affect the distribution of key resources, and the maintenance of C. spixii would depend on restoration of degraded areas, especially riparian forests, and the preservation of already existing natural areas. The Caatinga domain is very threatened by habitat loss and, for the success of this reintroduction project, the parties involved must act to protect the species and the resources it uses.     

Field Exposure Study of Polylactic Acid (PLA) Plastic Films in the Banana Fields of Costa Rica

For use by the banana industry of Costa Rica, polylactic acid (PLA) plastic ropes and banana finger shrouds must remain operational for 14 to 16 weeks, and they also must be able to break down in the soil after serving their purposes. The banana field at La Rebusca Farm (Costa Rica) and the experiment station at University of Costa Rica were selected for a field exposure study of Cargill EcoPla Generation II (GII) and Cargill EcoPla monolayer (Ca-I) PLA films. The average monthly temperature, relative humidity, and cumulative rainfall of the La Rebusca Farm and the University of Costa Rica site were 26 and 22°C, 92 and 84%, and 352 and 177 in., respectively. The PLA plastic films at the La Rebusca Farm lost their mechanical properties earlier than at the University of Costa Rica site because of the higher temperature and relative humidity of the banana farm. The Ca-I film meets the 14-week operational time frame and it is recommended for further studies as ropes and banana shrouds.