Susana Blanco García

Bioventing remediation and ecotoxicity evaluation of phenanthrene-contaminated soil.

The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5.5 kg of phenanthrene-contaminated soil and uncontaminated natural soil over a period of 7 months. Optimum conditions of mineralisation (humidity=60% WHC; C/N/P=100:20:1) were determined in a previous work. The evolution of oxygen consumption, carbon dioxide production, phenanthrene concentration and soil toxicity were studied on sacrificed columns at periods of 0, 3 and 7 months. Toxicity to soil and aquatic organisms was determined using a multispecies system in the soil columns (MS-3). In the optimal bioventing treatability test, we obtained a reduction rate in phenanthrene concentration higher that 93% after 7 months of treatment. The residual toxicity obtained at the end of the treatment was not attributed to the low phenanthrene concentration, but to the ammonia used to restore the optimal C/N ratio.

Mobilization Assessment and Possibility of Increased Availability of PAHs in Contaminated Soil Using Column Tests

Surfactants are well known to increase solubility/mobility of hydrocarbons and can be used to remediate contaminated water and soil. We wanted to explore if Ivey sol® 106 used at less than the critical micelle concentration (CMC) could effectively mobilize PAH (polycyclic aromatic hydrocarbons) from contaminated soil. The first step was to establish a measurement technique. Hence, a column leaching method was undertaken to investigate mobility of PAH-contaminated soil from a former gaswork facility. The methodology was based on a recycled flow of aqueous solution containing CaCl2 0.01M through two different soil columns. In the first column test, the free desorption of hydrocarbons was studied by recycling the solution through the soil column with a peristaltic pump and with a liquid/solid ratio of 2, based on ISO/DIS 18772. The solution was replaced with new solution every three days to aid desorption. In the second column test, the set-up was similar with the exception of the aforementioned recycling solution. In this case, a second column was filled with a resin, Amberlite XAD-2, which captures PAHs entering the solution through the soil column, cleaning it of hydrocarbons (induced desorption). The results obtained for induced desorption and free desorption with reposition showed that liberation of PAHs in the presence of resins was higher (7%) as opposed to free desorption (below 0.3%). These two experiments demonstrated low mobilization of PAHs. A third column test was performed using a non ionic surfactant, Ivey-sol® 106, 100 μg g−1 of soil below the CMC in the recycling solution. The introduction of Ivey-sol® 106 at 0.005%w/v increased desorption of PAHs to 32%, thus demonstrating the potential for increased bioavailability of the PAHs for bioremediation of the soil.

Seasonal variations in the activity in vitro of peripheral blood granulocytes in the turtle Mauremys caspica

Abstract 1. 1. In the present work we have studied different aspects of the phagocytic process in peripheral blood granulocytes from the turtle Mauremys caspica : (a) tissue adherence capacity, (b) spontaneous mobility and chemotaxis, (c) attachment and ingestion of foreign cells ( Candida albicans ) or inert particles (latex beads), and (d) capacity to digest ingested material measured by nitroblue tetrazolium (NBT) reduction. These studies were carried out in vitro at 37°C in autumn, winter, spring and summer. 2. 2. The adherence index showed significantly higher values in autumn, and smaller values in winter. The spontaneous mobility was not affected seasonally, but the chemotaxis was significantly increased in winter and decreased in autumn. The numbers of C. albicans attached and ingested as well as latex beads ingested per 100 granulocytes were higher in autumn and summer, and lower in winter and spring. The digestion capacity was greatly decreased in summer. 3. 3. The comparison between the results obtained here and those found using the same techniques in blood human granulocytes showed that these animals are endowed with an adequate phagocytic response.

Measurements of Hydroxylated Polycyclic Aromatic Hydrocarbons in Atmospheric Aerosols from an Urban Site of Madrid (Spain)

This paper describes an analytical methodology for the separation and quantitative determination by HPLC with fluorescence detection of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and their parents PAHs in atmospheric urban aerosol. The sampling site is located in the outskirts of Madrid and can be considered an open urban area. The aim of this work was the optimization of analytical methods, applied in several samples and characterize the concentration levels of selected PAHs-OH and PAHs. The preliminary results show concentrations between 2.5–53.2 pg/m for 2-OHPhenathrene (2-OHPH) and 27.8–34.5 pg/m for 1-OHPyrene (1-OHPYR).