Mercury bioaccumulation in organisms from three Puerto Rican estuaries

We analyzed mercury levels in shrimp (Palaemonetes sp.), Blue Crabs (Callinectes sp.), fish (Tarpon Megalops atlantica and Tilapia Tilapia mossambica), lizards (Ameiva exsul), Cattle Egret (Bubulcus ibis) and Moorhen (Gallinula chloropus) in three estuaries in Puerto Rico in 1988. There were no quantifiable concentrations greater than the method detection limit of mercury in shrimp, crabs and lizards from any site. Mercury levels were also below detection limits in Tilapia, except for specimens collected at Frontera Creek, allegedly contaminated with mercury. However, mercury levels ranged from 92–238 g/kg (wet weight) in Tarpon, a predaceous fish that feeds on smaller fish. Few of the birds had detectable levels of mercury. Our results indicate relatively low concentrations of mercury in biota collected in all of the three estuaries at most trophic levels, although 10 of 12 Tarpon fillet samples from Frontera had detectable mercury compared to 3 of 12 fillet samples for the other two lagoons.This project was partially funded by an EPA consent decree (Dynamac, Inc.) and NIEHS grant (ESO 5022) to EOSHI.     

Physical and chemical characterisation of metal finishing industrial wastes

In EU countries approximately 150,000 tons/year of galvanic sludges are generated by 4000 industrial units from the corresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications.     

Operational change as a profitable cleaner production tool for a brewery

The development and implementation of new procedures and operational changes in the production processes constitutes a powerful tool for the practical application of Cleaner Production in industries. In this work an operational change (new procedure) was developed for the elaboration of a type of beer which uses sugar as malt adjunct. The change consists in processing separately the three main components of the beer wort: malt extract, sugar and water, and use them properly in a different sequence than that used up to date in the traditional process. The new procedure was successfully assayed on industrial scale in Tínima brewery, located in Camagüey, Cuba, obtaining a good quality beer, technological and economical advantages with benefits for the environment, registering significant savings in energy (49%), sugar (4%), water (7%) and caustic soda (3%) consumption; and diminishing the surplus hot water (74%), waste generation (11%) and greenhouse gases emission (21%). Beer production capacity is increased also almost three times. With the application of the new technology to the Cuban beer type of 8 °P, it was achieved a total saving of US$ 481.83/1000 hL of beer produced.     

Water security as a challenge for the sustainability of La Serena-Coquimbo conurbation in northern Chile: global perspectives and adaptation

The aim of this study is to address the problem of balance between water scarcity and sustainability, which are the key components of water security of cities located in arid lands, particularly those under constant expansion and population growth. In this paper, we have highlighted the problem of water security for the sustainability of the La Serena-Coquimbo conurbation (LSCC). The coastal LSCC is located at the outlet of the Elqui River basin, in the southern edge of the Chilean Atacama Desert. We have analyzed the available information including drinking water production and consumption data, groundwater levels, precipitation data and population data. Between the years 2009 and 2013 the total water consumption for the area has significantly increased. On the other hand, there has been a significant decrease trend in the precipitations and the groundwater levels show a decrease of about 30 m between the years 1995 and 2014. In a few years, this urban area could face a general water scarcity problem if the drought conditions remain unchanged and if the water demand trend for the agricultural, mining and drinking water continues its increasing. The cities located in the arid lands are particularly vulnerable to water scarcity because their populations are highly concentrated and requires reliable supplies of water to make possible human and economic activities. We discuss how adaptation of the arid land urban areas to water scarcity requires a range of solutions, including economic incentives, regulatory measures, and technology.     

Interaction of alongshore sediment transport and habitat conditions at Laguna La Mancha, Veracruz, Mexico

The habitats of La Mancha Lagoon, located midway along the coast of Veracruz, Mexico, are responding to the change of sediment supply reaching its primary inlet at the Gulf of Mexico. Until several decades ago, an abundant alongshore supply of sediment created a periodic opening and closing of the La Mancha inlet. The hydrologic regime of the lagoon consisted of raised water level and lower salinity during the closures, whereas the open inlet favored lower water level, higher salinity, and sediment accumulation in the flood tidal delta. Currently, diminished alongshore sediment supply has affected the inlet morphology and the discharge regime. Associated with the reduced sediment supply, the inlet is open longer in its periodic cycle, the water level variation is reduced, the salinity contrasts are reduced, and the rate of sedimentation in the flood-tide delta is increased. This combination of alterations to the inlet area is changing the flooding regime and affecting the conditions in a very well-developed mangrove habitat at the lagoon margins as well as conditions within the aqueous portions of the lagoon. Management options produce a conflict between supporting the direction of change or preserving the existing habitats.     

Compressibility and shell failure in the European Atlantic <Emphasis Type="Italic">Patella</Emphasis> limpets

The specimens of Patella intermedia, Patella rustica, Patella ulyssiponensis and Patella vulgata were analysed for morphological and morphometric characters, and for the resistance to compression and crushing to a force applied at the apex. Shell shape in these species ranged from the high symmetrical cone, with a rounded base of P. rustica, to the flat, asymmetrical, narrow-pear-shaped base of P. ulyssiponensis. P. intermedia and P. vulgata showed intermediate morphologies. Shell thickness increased linearly with age, but differed in the four limpets. P. rustica had the thickest shells, and P. ulyssiponensis and P. vulgata had the thinnest shells. P. intermedia displayed intermediate shell thickness. Considering deformability and toughness, P. intermedia shells usually needed the highest force to compress in height, the highest pressure to collapse, and were appreciably deformed at collapse. On the opposite side, P. ulyssiponensis shells usually needed the lowest force to compress in height, the lowest pressure to collapse, and were much less deformed at collapse. P. intermedia shells were therefore the most deformable and tough, and P. ulyssiponensis, the most stiff and fragile. P. rustica and P. vulgata shells displayed intermediate behaviour. However, numerical simulations based on the finite element method using the experimentally determined shells’ geometry and thickness, but considering similar shells’ material and structure in the four species, predicted that shell toughness should be decreased in the order P. rustica >> P. intermedia > P. vulgata >> P. ulyssiponensis. P. rustica shells’ geometry (a high and centred cone) and thickness (very thick) were therefore, theoretically, the most fitted for shells to resist crushing by compression. Yet, in the experimental tests, they were not the most resistant shells. It was concluded that resistance to crushing was not a direct function of shell morphology and morphometry, but appeared to be mainly determined by shell deformability. This is most probably related to differences in the internal composition and architecture of the shell in the four species. By comparison with data reported in the literature on the pressures normally exerted by ocean waves, it was concluded that these limpets have resistances to crushing in far excess to pressures normally endured in nature, being therefore unlikely that these species are crushed by the action of even very strong waves on shores. Hard objects, like logs and boulders, can be hurled onto the shore by waves, and constitute a much greater threat to limpets than the waves themselves. The high toughness of the limpet shell can be related to resistance to the impact of incidental hard objects. There was no direct relationship between the habit preferences of these limpets and the resistance to crushing. Other factors are involved in the distribution of these species in the shores.     

Assessing the effects of pseudo-absences on predictive distribution model performance

Modelling species distributions with presence data from atlases, museum collections and databases is challenging. In this paper, we compare seven procedures to generate pseudo-absence data, which in turn are used to generate GLM-logistic regressed models when reliable absence data are not available. We use pseudo-absences selected randomly or by means of presence-only methods (ENFA and MDE) to model the distribution of a threatened endemic Iberian moth species (Graellsia isabelae). The results show that the pseudo-absence selection method greatly influences the percentage of explained variability, the scores of the accuracy measures and, most importantly, the degree of constraint in the distribution estimated. As we extract pseudo-absences from environmental regions further from the optimum established by presence data, the models generated obtain better accuracy scores, and over-prediction increases. When variables other than environmental ones influence the distribution of the species (i.e., non-equilibrium state) and precise information on absences is non-existent, the random selection of pseudo-absences or their selection from environmental localities similar to those of species presence data generates the most constrained predictive distribution maps, because pseudo-absences can be located within environmentally suitable areas. This study shows that if we do not have reliable absence data, the method of pseudo-absence selection strongly conditions the obtained model, generating different model predictions in the gradient between potential and realized distributions.     

Copper and lead ion removal from wastewater using fava d’anta fodder (Dimorphandra gardneriana Tulasne)

Environmental Geochemistry and Health - The contamination of bodies of water by potentially hazardous elements has in recent decades become an environmental problem that poses serious risks to...