Polycyclic aromatic hydrocarbons and their hydroxylated metabolites in fish bile and sediments from coastal waters of Colombia

Sediments and fish bile collected from the Atlantic coastal waters of Colombia were analyzed for 16 parent polycyclic aromatic hydrocarbons (PAHs), and 23 hydroxylated PAHs (OH-PAHs), respectively. Sediments contained overall mean SigmaPAH concentrations of 2090, 234 and 170 ng/g, dry wt, for Cartagena Bay, Caimanera Marsh, and Totumo Marsh, respectively. The mean concentration of the summed OH-PAHs in fish bile was 1250, 180 and 64.1 ng/g bile wt for Cartagena Bay, Caimanera Marsh, and Totumo Marsh, respectively. The results suggest that Cartagena Bay is heavily polluted by PAHs, and that exposure to high concentrations of PAHs together with other factors could contribute to the decreased health of fish living in this ecosystem. This is one of the first studies to describe the analysis of 23 individual OH-PAHs in fish bile, using authentic standards.     

Osmotic and chloride regulation in the hemolymph of the tiger prawn Penaeus monodon during molting in various salinities

The effect of molting on osmotic and chloride concentrations in the blood of the prawn Penaeus monodon Fabricius (20±3 g) at various salinities was investigated. Prawns were obtained from ponds in Iloilo, Philippines, in 1984. They were stocked in salinities of 8, 20, 32 and 44, and their hemolymph was sampled during molt (Time 0), and then 0.125, 0.25, 0.5, 1, 2, 4, 6, 10 and 14 d after molting. Prawns during and immediately after molt tended to conform to the environmental osmolality. Subsequent postmolt (0.5 d) stages displayed more divergence from external salinity. The isosmotic point was higher (940±30 mOsm kg^-1) during molt than during intermolt (663±8 mOsm/kg^-1), suggesting different osmotic requirements in early molt. Hyperregulation of hemolymph chloride below 20 S, as well as isoionic point (301±6 mM), were independent of molting stage. At 20 S and above, newly molted (0 to 0.25 d post-molt) individuals tended to conform to the external chloride concentration while intermolt (0.5 d) post-molt individuals did not. Contribution of hemolymph chloride to hemolymph osmolality was greater during intermolt than during ecdysis, suggesting an important role for other negatively charged ions during molt. When molt occurred in 20 S (the test salinity most similar to the isoionic salinity), there was little or no change in hemolymph osmolality or chloride concentration from 0 to 14 d postmolt. At 8, 32 and 44 S, the change from molt to intermolt values in hemolymph osmotic and chloride concentrations was hyperbolic. Non-linear least-squares regression showed that prawns generally achieved intermolt values within 1 d after molting. Prawns at intermolt regulated hemolymph osmolality (620 to 820 mOsm kg^-1) and chloride concentration (300 to 450 mM) at a much narrower range than during molt (520 to 1 170 mOsm kg^-1 and 250 to 520 mM, respectively). Hemolymph osmolality was a more sensitive indicator of physiological response than hemolymph chloride concentration. Distribution and culture of P. monodon might be limited in low salinities by its ability to maintain a hemolymph osmolality 500 mOsm kg^-1 during molt and 600 mOsm kg^-1 in intermolt, and in high salinities by its capacity to reduce the hemolymph osmolality from values at molt to those in intermolt. Osmotic and chloride concentrations in the blood of P. monodon clearly varied with both molt stage and salinity of the medium. Dependence on external factors, however, gradually declined in older molt stages, suggesting a reduction in integument permeability and greater development of ion absorption/secretion mechanisms as the exoskeleton hardened.SEAFDEC Contribution No. 197     

Ionic Dye Removal Using Solvent-Assisted Ionic Micellar Flocculation

Journal of Polymers and the Environment - The environmental impacts caused by dyes in industrial wastewater are incalculable, due to their adverse effects on the ecosystem and human life,...     

Trace elements in fish and oysters from Sepetiba Bay (Rio de Janeiro – Brazil) determined by total reflection X-ray fluorescence using synchrotron radiation

Trace elements were determined in fish and oysters from Sepetiba Bay, Brazil, by total reflection Xray fluorescence using synchrotron radiation (SRTXRF). Cr, Mn, Fe, Ni, Cu, Zn and Se were determined in fish muscles and organs and in oyster soft tissue. SRTXRF was shown to be a good tool for the analysis of trace elements from biological tissue samples. Overall, the levels of the analysed metals were higher in oysters than in the fish samples. Metals were not uniformly distributed throughout the body of the analysed fish. The detected concentrations of Cr, Zn and Se were very high in some samples, surpassing the maximum limits established by Brazilian legislation.     

Persistence of gemfibrozil, naproxen and mefenamic acid in natural waters

The occurrence of pharmaceuticals in natural waters is a potential threat to human nutrition and ecosystem quality. The persistence of the acidic pharmaceuticals gemfibrozil, naproxen and mefenamic acid was studied in surface waters of Maracaibo Lake and Tule reservoir (Venezuela) under laboratory conditions. A quick and easy analytical method was developed for the determination of the acidic drugs at microgram per liter levels using aqueous derivatization, liquid–liquid extraction and gas chromatography–mass spectrometry. Pharmaceuticals degradation followed a pseudo first-order kinetic and their half-lives were calculated for every experimental condition. Under sunlight, naproxen and mefenamic acid were degraded at moderate rates with half-lives from 9.6 ± 0.5 to 27.0 ± 6.6 days, while gemfibrozil had a higher persistence (t _1/2 = 119.5 ± 15.6 − 288.8 ± 61.3 days).     

Phosphorus mass balance and input load estimation from the wet and dry periods in tropical semiarid reservoirs

The dynamics of total phosphorus (TP) in 18 strategic reservoirs of the high-density reservoir network of the Brazilian semiarid was evaluated during the wet and dry periods for the past 12 years. Seasonal overlying concentrations presented no significant differences for about 90% of the reservoirs (p>0.05). This was attributed to a trade-off between the hydrological/limnological processes occurring in the two seasons. Then, a transient complete-mix mass balance model was applied with particular adaptations for the tropical semiarid reservoirs to estimate the TP load for each season. Because of the relatively well-mixed conditions and high hypolimnetic dissolved oxygen concentrations during the wet season, the wet load was assumed to represent the external TP load. On the other hand, because of the absence of reservoir inflow during the dry season, phosphorus release under anoxic sediment conditions and wind-induced resuspension under shallow water depths, the dry load was assumed to reflect the internal TP load. The maximum external loads were related to peak inflows, notably after drought periods. Consistently, the largest internal loads were obtained during the drought periods, when the reservoirs were shallower and more prone to phosphorus release and resuspension. By comparing the impact of the two input load types, the wet period load was predominant in 72% of the reservoirs. The areal phosphorus loads ranged from 0.66 to 7.29 gP m² year^?1, which were consistent with the literature, despite the very high density of reservoirs. Finally, power-law curves including data for all studied reservoirs were adjusted between the dry period load and volume, dry and wet period loads, wet period load and inflow, and total load and catchment area, resulting in satisfactory R² (0.84–0.98).

     

Integrating energy and land-use planning: socio-metabolic profiles along the rural–urban continuum in Catalonia (Spain)

Abandoning fossil fuels and increasingly relying on low-density, land-intensive renewable energy will increase demand for land, affecting current global and regional rural–urban relationships. Over the past two decades, rural–urban relationships all over the world have witnessed unprecedented changes that have rendered their boundaries blurred and have lead to the emergence of “new ruralities.” In this paper, we analyze the current profiles of electricity generation and consumption in relation to sociodemographic variables related to the use of time and land across the territory of Catalonia, Spain. Through a clustering procedure based on multivariate statistical analysis, we found that electricity consumption is related to functional specialization in the roles undertaken by different types of municipalities in the urban system. Municipality types have distinctive metabolic profiles in different sectors depending on their industrial, services or residential role. Villages’ metabolism is influenced by urban sprawl and industrial specialization, reflecting current “new ruralities.” Segregation between work activity and residence increases both overall electricity consumption and its rate (per hour) and density (per hectare) of dissipation. A sustainable spatial organization of societal activities without the use of fossil fuels or nuclear energy would require huge structural and sociodemographic changes to reduce energy demand and adapt it to regionally available renewable energy.     

An overview of uncertainties in modelling groundwater solute transport

Model predictions are uncertain because of uncertainties on future and/or anthropogenic stresses, parameter values and conceptual models. The first two groups of problems can be addressed through rather systematic methods (scenario analysis, error transmission techniques, automatic calibration algorithms, etc.). However, conceptual uncertainties are rarely given adequate attention. The objective of this paper is to synthesize conceptual difficulties associated with transport. These include: (1) processes that are significant at small scales may not be relevant at large scales; (2) inversely, new processes (e.g., dispersion) emerge in response to increase in scale and the way to represent them may depend on the assumed model structure; (3) the observed shapes of both breakthrough curves and pollutant plumes are not well represented by the classical transport equation; (4) porosities and dispersivities derived from field tracer tests often exhibit a directional dependence; etc. Though not directly related to solute transport, scale effects on hydraulic conductivity may also affect solute transport modelling. When these anomalies are examined, it is concluded that they are directly or indirectly caused by heterogeneity. Current approaches for dealing with heterogeneity can be divided into stochastic and deterministic. Stochastic methods have been successful in explaining qualitatively some anomalies of solute transport, but they appear to be far from reaching a stage at which they can be used routinely for solving realistic field problems. On the other hand, when applied with care, deterministic methods have been successfully used in actual problems. Yet, it can be argued that they fail to account for small-scale variability of concentrations so that they would become ineffective when dealing with nonlinear processes, such as chemical reactions. Relevance of on-going research for overcoming these difficulties is discussed.     

Extensive review of shale gas environmental impacts from scientific literature (2010–2015)

Extensive reviews and meta-analyses are essential to summarize emerging developments in a specific field and offering information on the current trends in the scientific literature. Shale gas exploration and exploitation has been extensively debated in literature, but a comprehensive review of recent studies on the environmental impacts has yet to be carried out. Therefore, the goal of this article is to systematically examine scientific articles published between 2010 and 2015 and identify recent advances and existing data gaps. The examined articles were classified into six main categories (water resources, atmospheric emissions, land use, induced seismicity, occupational and public health and safety, and other impacts). These categories are analyzed separately to identify specific challenges, possibly existing consensus and data gaps yet remained in the literature.