GOALS, SCOPE AND BACKGROUND: It has been observed that hydrocarbon treated wastewaters still contain high COD and a number of intermediates. This suggests that the required catabolic gene pool for further degradation might be absent in the system or, that its titer value is not significant enough. By providing the desired catabolic potential, the overall efficiency of the treatment system can be improved. This study aims to demonstrate this concept by bioaugmentation of a lab-scale reactor treating refinery wastewater with a consortium having the capacity to complement the alkB genotype to the available microbial population. METHODS: Two reactors were set up using activated biomass collected from a refinery treatment plant and operated at a continuous mode for a period of 8 weeks. The feed to both reactors was kept constant. Crude oil was spiked regularly. One reactor was bioaugmented with a consortium previously described for crude oil spill remediation. The efficiency of the bioaugmented reactor was demonstrated by reduced COD. The changes in the microbial population over a period of time were analyzed by RAPD. Catabolic activity of the biomass in both reactors was monitored by PCR. The presence of the catabolic loci was confirmed by Southern Hybridization. RESULTS AND DISCUSSION: 52.2% removal of COD was observed in the bioaugmented reactor while only 15.1% reduction of COD was observed in the reactor without bioaugmentation. The change in microbial population can be seen from the 4th week, which also corresponds to improved catabolic activity. The presence of the bedA locus was seen in all samples, which indicates the presence of aromatic degraders, but the appearance of the alkB locus, from the 6th week onwards, which was observed only in the samples from the bioaugmented reactor. The results suggest that the gene pool of the bioaugmented reactor has catabolic loci that can degrade accumulated intermediates, thus improving the efficiency of the system. CONCLUSIONS: In this study, improvement of efficiency of bioremediation was demonstrated by addition of catabolic loci that are responsible for degradation. Bioaugmentation was carried out in biomass that was collected from an ETP (effluent treatment plant) treating hydrocarbon containing wastewater to study the strategies for improvement of the treatment system. Biostimulation, only marginally improved the efficiency, when compared to bioaugmentation. The improved efficiency was demonstrated by COD removal. The presence of the alkB locus suggests the importance of a catabolic gene pool that acts on accumulated intermediates. It is well documented that straight chain aliphatics and intermediates of aromatic compounds after ring cleavage, accumulate in refinery wastewater systems, thereby hindering further degradation of the wastewater. Supplementation of a catabolic gene pool that treats the lower pathway compounds and alkanes will improve the overall efficiency. In this study, results suggest that the alkB locus can also be used to monitor the degradative mode of the activated biomass. RECOMMENDATIONS AND PERSPECTIVE: . Pollution from petroleum and petroleum products around the globe are known to have grave consequences on the environment. Bioremediation, using activated sludge, is one option for the treatment of such wastes. Effluent treatment plants are usually unable to completely degrade the wastewater being treated in the biological unit (the aerator chambers). The efficiency of degradation can be improved by biostimulation and bioaugmentation. This study demonstrates the improved efficiency of a treatment system for wastewater containing hydrocarbons by bioaugmentation of a consortium that supports degradation. Further experiments on a pilot scale are recommended to assess the use of bioaugmentation on a large scale. The use of molecular tools, like DNA probes for alkB, to monitor the system also needs to be explored.

GOAL, SCOPE AND BACKGROUND: Biosolids, i.e., treated sewage sludge, are commonly used as a fertilizer and amendment to improve soil productivity. Application of biosolids to meet the nitrogen (N) requirements of crops can lead to accumulation of phosphorus (P) in soils, which may result in P loss to water bodies. Since 1996, biosolids have been applied to a Pinus radiata D. Don plantation near Nelson City, New Zealand, in an N-deficient sandy soil. To investigate sustainability of the biosolids application programme, a long-term research trial was established in 1997, and biosolids were applied every three years, at three application rates, including control (no biosolids), standard and high treatments, based on total N loading. The objective of this study was to evaluate the effect of repeated application of biosolids on P mobility in the sandy soil. MATERIALS AND METHODS: Soil samples were collected in August 2004 from the trial site at depths of 0–10, 10–25, 25–50, 50–75, and 75–100 cm. The soil samples were analysed for total P (TP), plant-available P (Olsen P and Mehlich 3 P), and various P fractions (water-soluble, bioavailable, Fe and Al-bound, Ca-bound, and residual) using a sequential P fractionation procedure. RESULTS AND DISCUSSION: Soil TP and Olsen P in the high biosolids treatment (equivalent to 600 kg N ha⁻¹ applied every three years) had increased significantly (P<0.05) in both 0–10 cm and 10–25 cm layers. Mehlich 3 P in soil of the high treatment had increased significantly only at 0–10 cm. Olsen P appeared to be more sensitive than Mehlich 3 P as an indicator of P movement in a soil profile. Phosphorus fractionation revealed that inorganic P (Al/Fe-bound P and Ca-bound P) and residual P were the main P pools in soil, whereas water-soluble P accounted for approximately 70% of TP in biosolids. Little organic P was found in either the soil or biosolids. Concentrations of water-soluble P, bioavailable inorganic P (NaHCO₃ Pi) and potentially bioavailable inorganic P (NaOH Pi) in both 0–10 and 10–25 cm depths were significantly higher in the high biosolids treatment than in the control. Mass balance calculation indicated that most P applied with biosolids was retained by the top soil (0–25 cm). The standard biosolids treatment (equivalent to 300 kg N ha⁻¹ applied every three years) had no significant effect on concentrations of TP, Mehlich 3 P and Olsen P, and P fractions in soil. CONCLUSIONS: The results indicate that the soil had the capacity to retain most biosolids-derived P, and there was a minimal risk of P losses via leaching in the medium term in the sandy forest soil because of the repeated biosolids application, particularly at the standard rate. RECOMMENDATIONS AND PERSPECTIVES: Application to low-fertility forest land can be used as an environmentally friendly option for biosolids management. When biosolids are applied at a rate to meet the N requirement of the tree crop, it can take a very long time before the forest soil is saturated with P. However, when a biosolids product contains high concentrations of P and is applied at a high rate, the forest ecosystem may not have the capacity to retain all P applied with biosolids in the long term.

- DOI: http://dx.doi.org/10.1065/espr2006.04.299 Goal, Scope and Background This paper describes a statistical modelling approach, suggested as a policy tool in the Athens area for the assessment of the emissions reduction level required to meet the air quality standards for two criteria air pollutants, namely CO and NO2. Methods. More than ten years of hourly CO and NOx-NO2 concentration data measured by the monitoring network of the Hellenic Ministry for the Environment, Physical Planning and Public Works were analyzed and the original dataset has been reduced using a data evaluation procedure. Results and Discussion Seasonal pollutant concentration trends suggested that the reduction of CO and NOx concentrations observed in the beginning of the '90s is almost entirely attributed to the increase of the catalyst-equipped cars during this period. The numerical parameters of an empirical model relating EU standard exceedances with mean annual concentrations were defined and the model was validated using datasets from years that were not used for the estimation of these parameters. This model was used in conjunction with a roll-back equation as a policy tool for the assessment of the effect of different CO and NOx emissions reduction scenarios on air quality standard compliance for CO and NO2. Results predicted with this empirical modelling approach were assessed with monitored data averaged over a 3-year period, giving satisfactory results. Conclusion A methodology suggested for assessing the effects of different emissions reduction scenarios on air quality standard attainment was successfully applied for CO and NO2 in the Athens area. Recommendation and Perspective The proposed methodology can provide a useful tool for the evaluation of policies already in progress as well as the development of future policies for emissions reduction in urban areas with similar characteristics, aiming at air quality standard compliance on a timely manner. Such a methodology could be applied in other urban areas of Greece characterized by dense traffic, therefore assisting the development of national policies in relation to air pollutants for which standard exceedances occur.

BACKGROUND, AIMS AND SCOPE: Research and development has its own benefits and inconveniences. One of the inconveniences is the generation of enormous quantity of diverse toxic and hazardous wastes and its eventual contamination to soil and groundwater resources. Ethidium bromide (EtBr) is one of the commonly used substances in molecular biology experiments. It is highly mutagenic and moderately toxic substance used in DNA-staining during electrophoresis. Interest in phytoremediation as a method to solve chemical contamination has been growing rapidly in recent years. The technology has been utilized to clean up soil and groundwater from heavy metals and other toxic organic compounds in many countries like the United States, Russia, and most of European countries. Phytoremediation requires somewhat limited resources and very useful in treating wide variety of environmental contaminants. This study aimed to assess the potential of selected tropical plants as phytoremediators of EtBr. MATERIALS AND METHODS: This study used tomato (Solanum lycopersicum), mustard (Brassica alba), vetivergrass (Vetiveria zizanioedes), cogongrass (Imperata cylindrica), carabaograss (Paspalum conjugatum), and talahib (Saccharum spontaneum) to remove EtBr from laboratory wastes. The six tropical plants were planted in individual plastic bags containing soil and 10% EtBr-stained agarose gel. The plants were allowed to establish and grow in soil for 30 days. Ethidium bromide content of the test plants and the soil were analyzed before and after soil treatment. Ethidium bromide contents of the plants and soils were analyzed using an UV VIS spectrophotometer. RESULTS: Results showed a highly significant (p≤0.001) difference in the ability of the tropical plants to absorb EtBr from soils. Mustard registered the highest absorption of EtBr (1.4±0.12 μg kg⁻¹) followed by tomato and vetivergrass with average uptake of 1.0±0.23 and 0.7±0.17 μg kg⁻¹ EtBr, respectively. Cogongrass, talahib, and carabaograss had the least amount of EtBr absorbed (0.2±0.6 μg kg⁻¹). Ethidium bromide content of soil planted to mustard was reduced by 10.7%. This was followed by tomato with an average reduction of 8.1%. Only 5.6% reduction was obtained from soils planted to vetivergrass. Soils planted to cogongrass, talahib, and carabaograss had the least reduction of 1.52% from its initial EtBr content. DISCUSSION: In this study, mustard, tomato, and vetivergrass have shown their ability to absorb EtBr from contaminated soil keeping them from expanding their reach into the environment and preventing further contamination. Its downside, however, is that living creatures including humans, fish, and birds, must be prevented from eating the plants that utilized these substances. Nonetheless, it is still easier to isolate, cut down, and remove plants growing on the surface of the contaminated matrices, than to use strong acids and permanganates to chemically neutralize a dangerous process that can further contaminate the environment and pose additional risks to humans. Though this alternative method does not totally eliminate eventual environmental contamination, it is by far produces extremely insignificant amount of by-products compared with the existing processes and technologies. CONCLUSIONS: Mustard had the highest potential as phytoremediator of EtBr in soil. However, the absorption capabilities of the other test plants may also be considered in terms of period of maturity and productivity. RECOMMENDATIONS AND PERSPECTIVES: It is recommended that a more detailed and complete investigation of the phytoremediation properties of the different plants tested should be conducted in actual field experiments. Plants should be exposed until they reach maturity to establish their maximum response to the toxicity and mutagenecity of EtBr and their maximum absorbing capabilities. Different plant parts should be analyzed individually to determine the movement and translocation of EtBr from soil to the tissues of plants. Since this study has established that some plants can thrive and dwell in EtBr-treated soil, an increased amount of EtBr application should be explored in future studies. It is suggested therefore that a larger, more comprehensive exploration of phytoremediation application in the management of toxic and hazardous wastes emanating from biotechnology research activities should be considered especially on the use of vetivergrass, a very promising tropical perennial grass.

Working group on effects of the convention on long-rangr transboundary air pollution