The endocrine system, specifically relating to sex hormones, and genetic material can be targets of environmental contaminants. Environmental contaminants in the Rio Grande region may originate from industrial or agricultural processes and growing populations lacking proper water and sewage infrastructure. Cliff (Petrochelidon pyrrhonota) and cave (P. fulva) swallows breeding near the Rio Grande were selected to monitor aromatase activity alterations and DNA damage. Swallows were sampled at six sites along the Rio Grande from Brownsville to Laredo, and a reference site (Somerville) 350 miles north of the Rio Grande. DNA damage, based on nuclear DNA content, was determined by flow cytometry. A significantly larger mean half peak coefficient of variation (HPCV) of DNA content in contaminated sites compared to a reference site reflects possible chromosomal damage. No detectable HPCV differences were observed in cave swallows among locations, notwithstanding the presence of mutagenic contaminants. Selenium may provide a protective role against genetic damage. However, cliff swallows from Laredo had significantly higher HPCV values than those from Somerville. DNA damage could be attributed to metals and polycyclic aromatic hydrocarbons released near Laredo. Brains and gonads, two estrogen-dependent organs, were tested for aromatase activity with a tritiated water method. Brain aromatase activity was higher, though not always statistically, for male cave and male and female cliff swallows. Dichlorodiphenyldichloroethylene (DDE) may play a role in the increased activity. Female cave swallows in Llano Grande appeared to have a greatly depressed brain aromatase activity, possibly attributed to past human use of toxaphene. Testicular and ovarian aromatase activity in cliff and cave swallows from Rio Grande was higher than in those from Somerville, though not always significantly. DDE, atrazine, sewage treatment plant contaminants (phthalates, alkylphenols, ethynylestradiol), metals, or other pollutants could play a role in the increased gonadal activity. Increased aromatase activity, in association with contaminants, may be easier to detect in testes of male birds which normally exhibit low levels of estrogen. Siterelated contaminants may be playing a role in DNA damage and aromatase alterations. This is the first known study which uses aromatase activity as an endocrine disruptor indicator in wild birds.

No description available.

No description available.

Snow efficiently scavenges organic contaminants from the atmosphere. Those chemicals can be released in short, concentrated pulses during spring snowmelt, potentially affecting both aquatic and terrestrial environments. In order to investigate the behavior of organic contaminants in melting snow laboratory experiments were conducted using artificial snow spiked with the organic target substances naphthalene, phenanthrene, pyrene, benzo(ghi)perylene, lindane, and atrazine. The behavior of those substances during melting is dependent on their partitioning between the different phases present within the bulk snow. Very water soluble organic chemicals, such as atrazine, are preferentially released at an early stage of melting similar to inorganic ions. This first chemical flush becomes more pronounced when a deep, aged, and relatively homogeneous snow pack is exposed to intense melting. Hydrophobic substances attached to particles, such as high molecular weight polycyclic aromatic hydrocarbons, are often released at the very end of the melt period. Dirt cones at the surface of a deep snow pack amplify this late chemical enrichment. Whereas chemicals that are clearly hydrophilic or hydrophobic are likely to be released in pulse loads, the snowmelt behavior of chemicals with intermediate partitioning properties, such as lindane, is more dependent on the varying snow pack and melt characteristics. A notable fraction of volatile chemicals may transfer from the melting snow pack to the lower atmosphere due to evaporation. Shallow snow covers in temperate regions with depths below 10cm that are exposed to recurrent melt phases during the winter are less likely to lead to pulse releases. When the melt water runs off as overland flow over frozen ground, pollutants are directly transferred into catchment streams, and their water quality is affected most. Melt water flow along the soil subsurface dilutes and buffers organic contaminant loads. The findings of this laboratory study may assist in the development of contaminant fate models that includes snowmelt processes. The results may further help to explain observations of organic contaminants in natural snow environments.

Snow efficiently scavenges organic contaminants from the atmosphere. Those chemicals can be released in short, concentrated pulses during spring snowmelt, potentially affecting both aquatic and terrestrial environments. In order to investigate the behavior of organic contaminants in melting snow laboratory experiments were conducted using artificial snow spiked with the organic target substances naphthalene, phenanthrene, pyrene, benzo(ghi)perylene, lindane, and atrazine. The behavior of those substances during melting is dependent on their partitioning between the different phases present within the bulk snow. Very water soluble organic chemicals, such as atrazine, are preferentially released at an early stage of melting similar to inorganic ions. This first chemical flush becomes more pronounced when a deep, aged, and relatively homogeneous snow pack is exposed to intense melting. Hydrophobic substances attached to particles, such as high molecular weight polycyclic aromatic hydrocarbons, are often released at the very end of the melt period. Dirt cones at the surface of a deep snow pack amplify this late chemical enrichment. Whereas chemicals that are clearly hydrophilic or hydrophobic are likely to be released in pulse loads, the snowmelt behavior of chemicals with intermediate partitioning properties, such as lindane, is more dependent on the varying snow pack and melt characteristics. A notable fraction of volatile chemicals may transfer from the melting snow pack to the lower atmosphere due to evaporation. Shallow snow covers in temperate regions with depths below 10cm that are exposed to recurrent melt phases during the winter are less likely to lead to pulse releases. When the melt water runs off as overland flow over frozen ground, pollutants are directly transferred into catchment streams, and their water quality is affected most. Melt water flow along the soil subsurface dilutes and buffers organic contaminant loads. The findings of this laboratory study may assist in the development of contaminant fate models that includes snowmelt processes. The results may further help to explain observations of organic contaminants in natural snow environments.

. Un modelo completo del transporte de un compuesto orgánico (CO) en la zona no saturada del suelo en condiciones no isotérmicas ha de incorporar una descripción detallada de los flujos másicos y energéticos. En este trabajo se presenta un modelo que considera cuatro balances de materia: uno para el agua líquida, uno para la fase gaseosa en su conjunto, uno para el vapor de agua y, finalmente, uno para el CO. El balance de energía considera el transporte conductivo, convectivo y dispersivo en cada una de las fases de la matriz porosa. Las condiciones de contorno impuestas en la superficie del suelo son dinámicas con variaciones periódicas que describen los ciclos diarios. Para el balance de energía se consideran los flujos radiativos que inciden y se reflejan desde el suelo, el flujo convectivo hacia la atmósfera y el flujo que por diferentes mecanismos se dirige hacia el interior del suelo. Los resultados de la simulación del transporte no isotérmico de agua se han contrastado favorablemente con experiencias de campo, reportadas en la bibliografía, en condiciones de sequedad progresiva del suelo. Se ha simulado el transporte de benceno como ejemplo de CO volátil y del lindano como CO poco volátil y con mucha tendencia a particionarse en la materia orgánica. En estas simulaciones el CO muestra variaciones periódicas en los flujos de volatilización, debidas a las variaciones de temperatura y humedad durante un ciclo diario. En el caso del lindano se han observado oscilaciones de amplitud superior a un orden de magnitud. / . A complete transport model for organic compound migration in the unsaturated soil zone under non-isothermal conditions must include a detailed description of mass and energy fluxes. In this work a model is presented, which considers four different mass balances: one for the liquid phase, one for the gaseous phase as a whole, one for the water vapor and, finally, one for the organic compound. The energy balance considers conductive, convective and dispersive transport for each phase. The energy top boundary condition takes into account downwards and upwards radiative fluxes, convective flow to the atmosphere and energy transport into the soil. Simulation results obtained for the water transport under non-isothermal conditions agree with experimental results reported in the literature for soils that dry progressively. Benzene and Lindane have been chosen as examples of volatile and non-volatile organic compounds, respectively. Simulation results for volatilization flux exhibit periodic variations due to the temperature and humidity diurnal cycle. In the case of Lindane amplitudes as high as one order of magnitude have been observed.

The large surface area of cohesive sediments enables them to act as sinks for marine contaminants. Thus the dispersal of such contaminants is partly controlled by the resuspension and transport of fine sediments. The Cohesive Sediment Dynamics Study (COSEDS) group was established to gain a better understanding of the erosion, resuspension,t ransport and deposition of fine particulate matter, particularly during storm conditions. As part of this study, measurementso f wave heights and orbital velocities, near bed currents and suspended sediment concentrations were monitored using instruments housed on free-standing frames deployed in Morecambe Bay and on the Sellafield mud patch in the Eastern Irish Sea. Acoustic and Miniature Optical Backscatter Sensors (ABS and MOBS) were calibrated in a resuspension tank which allowed conversion of the raw backscattered field data into information on the size and concentration of the material in suspension. The contrast in particle size sensitivity of the ABS and the MOBS results in a big difference in the response of the ABS and the MOBS to the particle size distribution of the field site sediments. Thus, in an environment of mixed particle sizes, the ABS and the 'MOBS can be used in conjunction with one another to provide information about the suspended sediments. Hydrodynamic data from four sites on the Sellafield mud patch enabled shear velocity estimates to be made using the Inertial Dissipation Method. Time-series of drag. coefficient and roughness length measurementss howed both temporal and spatial variation in the observations. The spatial difference in the observations has been attributed to a change in the size distribution of the bed sediments between sites. The cause of the temporal variation in the observed roughness is thought to have been due to a changing flow regime, a combination of wave-current interaction and the presence of bed forms. Simple boundary layer models enabled the reproduction of the shear velocity values and the drag coefficient in both rough-turbulent, smooth-turbulent and transitional flow regimes. The direct relationship between the suspended sediment and the tidal currents indicated local erosion and, pickup from the seabed. The optical backscatter data revealed the resuspensiono f sedimentb y waves at times of high orbital velocities and by tidal currents at other times. Estimateso f suspendeds edimentf lux were computed from the product of the vertical integration of velocity profiles and concentration profiles, which were predicted assuming a Rouse-type profile. Flux estimates at each of the sites indicated a net movement of sediment northwards throughout the duration of the two week deployment. For a more detailed picture of transport patterns, and hence contaminant paths, it has been shown that nearb ed hydrodynamicm easurementsa re required for a longer time period

La incineració amb o sense recuperació d’energia pot ser una opció per a la gestió adequada dels residus, però la preocupació pública sobre la incineració i la importància de desenvolupar estratègies sostenibles de residus, ha comportat l’aparició de noves tecnologies. En aquest estudi s’han determinat els nivells ambientals de contaminants químics i microbiològics en diferents matrius (aire, vegetació i sòls) a les rodalies de tres plantes de tractament de residus de Catalunya (IRSU de Tarragona, ERI de Constantí i Ecoparc-2 de Montcada i Reixac). La valorització energètica de residus i el tractament mecànic-biològic no suposen un risc addicional per a la salut humana derivat de l’exposició a diversos contaminants químics i microbiològics. En la línia de la Directiva Marc de Residus, aquests sistemes poden ser alternatives adients per al tractament dels residus, ja que l’impacte ambiental derivat de les emissions de PCDD/Fs, metalls, COVs i bioaerosols és relativament baix. / Incineration with or without energy recovery is likely to be an option for proper waste management, but public concern about incineration and the importance of developing sustainable strategies for waste has led to the emergence of new technologies. In this study we have determined levels of environmental chemical and microbiological contaminants in different matrices (air, soil and vegetation) in the vicinity of three waste treatment plants in Catalonia (Municipal Solid Waste Incinerator of Tarragona, Hazardous Waste Incinerator of Constantí, and Municipal Waste Organic Fraction Treatment Plant of Montcada i Reixac). Waste energy recovery and mechanical-biological treatment should not mean additional risk to human health when exposing to various chemical and microbiological contaminants. Following Waste Framework Directive, these systems can be appropriate waste management alternatives as the environmental impact caused by emissions of PCDD/Fs, metals, VOCs and bioaerosols is relatively low.

The importance of the cryosphere, and of sea ice in particular, for contaminant transport and redistribution in the Arctic was pointed out in the literature. However, studies on contaminants in sea ice are scarce, and entirely neglect the sea ice geophysical and thermodynamic characteristics as well as interactions between various cryospheric compartments. This thesis addresses those gaps. Ice formation was shown to have a significant concentrating impact on the levels of HCHs in the water just beneath the ice. Both geophysical and thermodynamic conditions in sea ice were shown to be crucial in understanding pathways of accumulation or rejection of HCHs. Although HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring, upward migration of brine from the ice to the snow in the winter has an effect on levels of HCHs in the snow by up to 50 %. In the spring, when snow melt water percolates into the ice delivering HCHs to the upper ocean via desalination by flushing, levels of HCHs in the ice can increase by up to 2 %-18 % and 4 %-32 % for α- and γ-HCH, respectively. Brine contained within sea ice currently exhibits the highest HCH concentrations in any abiotic Arctic environment, exceeding under-ice water concentrations by a factor of 3 in the spring. This circumstance suggests that the brine ecosystem has been, and continues to be, the most exposed to HCHs. α-HCH levels were shown to decrease rapidly in the last two decades in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea due to degradation. If the rate of degradation does not change in the near future, the majority of α-HCH could be eliminated from the Beaufort Sea by 2020, with concentrations in 2040 dropping to < 0.006 ng/L and < 0.004 ng/L in the PML and the PL, respectively. Elimination of α-HCH from sea water takes significantly longer than from the atmosphere, with a lag of approximately two decades.

No description available.