Succinic acid, a low molecular weight dicarboxylic acid was used to leach out heavy metals from Willamette Valley soil (contaminated separately with lead, copper, and zinc) in form of water-soluble organo-metal complexes. The research tasks included developing synthetic contaminated soils representative of those found at Superfund sites and making heavy metal adsorption and desorption studies. Fixed amounts of single-metal contaminated soil were treated with succinic acid under varying conditions of pH and organic ligand concentration. Based on the total metal mobilized into the aqueous phase, the optimum values of pH and organic acid were established for each metal. Since the direct determination of all species solubilized by the organic acid solution was not possible, a computer speciation program called MICROQL was used to determine the concentration of metal species in solution containing several metals and potential ligands. The results indicate that succinic acid is capable of significantly altering the partitioning of metals between the soil and the aqueous phase. Higher concentrations of the organic acid resulted in higher removal of metal from the soil. In case of lead and copper, low pH (3.5) succinic acid flushing solution was found to be the most effective, while a pH range of 4.5-5.5 was deemed optimum for zinc. The results also established that the extent of removal of any metal depended not only upon the the stability constant of the organo-metal complex, but also on its mode of retention within the soil. / Graduation date: 1993

Gas inFusion? is a novel remedial technology that dissolves CO₂ into water under pressure for NAPL recovery. As the supersaturated liquid flows through the porous medium gas evolution occurs in situ as the system returns to thermodynamic equilibrium. The evolution of gas bubbles leads to NAPL recovery by two mechanisms: 1) volatilization and 2) mobilization by the NAPL spreading in a film around the rising bubbles. Laboratory experiments by Li demonstrated that injecting the supersaturated water into a porous medium minimized the buoyancy driven flow of gas and the fingering phenomena that limit typical gas sparging. The distribution of carbon dioxide at partial pressures (p_CO2) above the applicable hydrostatic pressure and the evolved gas phase were determined in two field experiments conducted in the relatively homogeneous fine to medium sand at CFB Borden. First, CO₂-supersaturated water was injected into a single point located approximately 4 metres below ground surface. Then this injection was repeated with pumping of two nearby wells to see if the lateral distribution of CO₂ gas could be controlled hydraulically. Groundwater monitoring of p_CO2 above the hydrostatic pressure and geophysical surveys (neutron measurements, surface ground penetrating radar (GPR), and cross-borehole GPR) to find zones of induced gas content were supported by hydraulic monitoring and physical observations of gas bubble distribution at the water table. <br /><br /> Based on the results of these tests, enhanced CO₂ levels above the hydrostatic pressure were observed up to 5. 5-7. 0 m from the injection point and the gas phase up to ~5. 3 m. It was not possible to determine the impact hydraulic control had on the lateral distribution of CO₂ due to problems with the experiment. The distribution of the gas phase was heterogeneous with CO₂ gas pockets forming below low permeability layers, as evidenced by surface GPR, permeameter tests, and grain size analyses. These gas pockets accumulated until sufficient pressure built up to overcome the displacement pressure of these lower permeability layers. At this point there is evidence of CO₂ breakthrough in the cross-borehole GPR data and physical observations of gas bubbles at the water table. These observations are consistent with previous investigations, which indicate that although the Borden aquifer is homogeneous, distinct horizontal layering is present with sufficient variations in permeability/displacement pressure to trap and cause some lateral spreading of a gas phase. The evidence of channeling and the impact of heterogeneities on gas distribution are consistent with air sparging studies.

Sites where 2-chlorobutadiene-1,3 (chloroprene) and 2,3-dichlorobutadiene-1,3 (DCBD) are synthesized for use in chlorobutyl rubber have the potential to release a mixture of at least five chlorinated butenes and butadienes including trans-1,4-dichlorobutene-2 (1,4-DCB-2), 3,4-dichlorobutene-1 (3,4-DCB-1), 2,3,4-trichlorobutene-1 (2,3,4-TCB-1), chloroprene and DCBD into the groundwater environment. Granular iron has been shown to be effective in the remediation of groundwater contaminated with chlorinated organic compounds by reductive dechlorination. To evaluate the possibility of using granular iron in the remediation of the above contaminants a series of batch and column experiments were conducted at the laboratory scale. Chlorine mass balance calculations showed that each compound, with the exception of DCBD, could be fully dechlorinated by the use of granular iron. Kinetic data and proposed reaction pathways, however, suggest that DCBD can also be fully dechlorinated by granular iron. Normalization of observed pseudo-first-order reaction half-lives indicated that compounds were degrading much slower in batch experiments than in column experiments. This, along with the observation that temperature did not affect degradation in batch experiments, led to the conclusion that mass transport to the iron surfaces was limiting degradation rates in batch experiments. Results showed that the three chlorinated butenes degraded much faster (normalized column half-lives ranged from 1.6 to 5.2 min) than the two chlorinated butadienes (normalized column half-lives ranged from 115 to 197 min). Chlorinated and non-chlorinated intermediates were identified. It was determined that all contaminants degrade to 1,3-butadiene as a reaction intermediate which then degraded to a mixture of non-harmful end products consisting of 1-butene, cis-2-butene, trans-2-butene and n-butane. The reaction pathway from 1,4-DCB-2 to 1,3-butadiene was proposed to be a reductive elimination similar to reductive β-elimination. 3,4-DCB-1 and 2,3,4-TCB-1 were proposed to undergo reductive β-elimination reactions resulting in 1,3-butadiene and chloroprene intermediates, respectively. Degradation of chloroprene and DCBD occurred via hydrogenolysis pathways while 1,3-butadiene underwent catalytic hydrogenation resulting in the observed end products. The results suggest that granular iron may be an effective treatment for groundwater contaminated with these compounds.

An emplaced source of coal tar creosote within the sandy Borden research aquifer has provided an opportunity to document the long term (5140 days) natural attenuation for this complex mixture. Plumes of dissolved chemicals were produced by the essentially horizontal groundwater flowing at about 9 cm/day. Eleven chemicals were extensively sampled seven times using a monitoring network of ~280 14-point multilevel samplers. A model of source dissolution using Raoult’s Law adequately predicted the dissolution of nine of eleven compounds analysed. Mass transformation has limited the extent of the plumes as groundwater flowed more than 500 m yet the plumes are no longer than 50 m. Phenol and xylenes were removed and naphthalene was attenuated from its maximum extent on day 1357. Some compound plumes reached an apparent steady state and the plumes of other compounds (dibenzofuran and phenanthrene) are expected to continue to expand due to an increasing mass flux and limited degradation potential. Biotransformation is the major process controlling natural attenuation at the site. The greatest organic mass loss is associated with the high solubility compounds. However, the majority of the mass loss for most compounds has occurred in the source zone. Oxygen is the main electron acceptor yet the amount of organics lost cannot be accounted for by aerobic mineralization or partial mineralization alone. After 10 years the source zone was treated with permanganate in situ to reduce the flux of contaminants into the dissolved plume and to permit natural attenuation to further reduce the plume extent. A sufficient mass of permanganate was injected to oxidize ~10% of the residual source. Laboratory experiments demonstrated that eight of ten of the study compounds were readily oxidized by permanganate. Once treated oxidized compounds displayed a reduced plume mass and mass discharge while they migrated through the monitoring network. Once beyond the monitoring network the mass discharge and plume mass of these compounds returned to pre-treatment trends. Non-reactive compounds displayed no significant decrease in mass discharge or plume mass. Overall the partial in situ chemical oxidation of the coal tar creosote source produced no long-term effect on the dissolved plumes emanating from the source.

Air sparging is a technique used to remediate gasoline contamination. In sparging, air is injected below the target zone and removes contamination via two separate mechanisms; volatilization and biodegradation. In volatilization, the air contacts the contamination as it moves upward. The contaminant will partition to the vapor phase based on its volatility and will be removed as the air reaches the atmosphere. For biodegradation, the oxygen in the airstream is used for microbial activity. Pulsed air sparging, otherwise known as pulsed biosparging, has been found to be more effective than continuous air sparging. Pulsed biosparging enhances treatment because it induces groundwater movement and mixing. The general mechanisms for treatment of gasoline sources using air sparging are relatively well characterized. However, air flow through the subsurface and the total hydrocarbon mass lost are difficult to predict and quantify. This project was intended to quantify the mass lost through volatilization and through biodegradation at the E10 gasoline source using pulsed biosparging, and to determine the effect of the source zone removal on downgradient dissolved BTEX concentrations. The remedial system consisted of two major components: the air sparging system, with three injection points; and a soil gas collection system. The soil gas collection system was comprised of an airtight box that covered the source area and the monitoring wells upgradient and downgradient of the source. Off-gas from the soil gas collection system was monitored continuously using a PID. The off-gas was also sampled frequently for BTEX, pentane, and hexane to determine the hydrocarbon mass removed; and for O2 and CO2 to determine biodegradation rates. The remedial system ran for approximately 280 hours over 33 days. Of the estimated 22.3 kg of gasoline residual in the source zone, 4.6 kg or 21% of the residual was removed via volatilization and 4.9 kg or 22% of the residual was removed via biodegradation. Leakage outside the system was estimated at less than 0.1% of the total mass. Groundwater samples were collected when the last sparged air was calculated to arrive at the row 2 downgradient fence. The average BTEX groundwater concentration after sparging was 40% of the pre-sparging concentration. The benzene mass discharge decreased 27%, the ethylbenzene mass discharge decreased 65%, the p/m-xylene mass discharge decreased 6%, and the o-xylene mass discharge decreased 5%. The mass discharge for naphthalene and TMB isomers increased 19%. However, these values fit in with long-term groundwater concentration trends. Additional sampling is recommended to determine if the sparging made a significant impact on mass discharge leaving the source.

Gas inFusion? is a novel remedial technology that dissolves CO₂ into water under pressure for NAPL recovery. As the supersaturated liquid flows through the porous medium gas evolution occurs in situ as the system returns to thermodynamic equilibrium. The evolution of gas bubbles leads to NAPL recovery by two mechanisms: 1) volatilization and 2) mobilization by the NAPL spreading in a film around the rising bubbles. Laboratory experiments by Li demonstrated that injecting the supersaturated water into a porous medium minimized the buoyancy driven flow of gas and the fingering phenomena that limit typical gas sparging. The distribution of carbon dioxide at partial pressures (p_CO2) above the applicable hydrostatic pressure and the evolved gas phase were determined in two field experiments conducted in the relatively homogeneous fine to medium sand at CFB Borden. First, CO₂-supersaturated water was injected into a single point located approximately 4 metres below ground surface. Then this injection was repeated with pumping of two nearby wells to see if the lateral distribution of CO₂ gas could be controlled hydraulically. Groundwater monitoring of p_CO2 above the hydrostatic pressure and geophysical surveys (neutron measurements, surface ground penetrating radar (GPR), and cross-borehole GPR) to find zones of induced gas content were supported by hydraulic monitoring and physical observations of gas bubble distribution at the water table. <br /><br /> Based on the results of these tests, enhanced CO₂ levels above the hydrostatic pressure were observed up to 5. 5-7. 0 m from the injection point and the gas phase up to ~5. 3 m. It was not possible to determine the impact hydraulic control had on the lateral distribution of CO₂ due to problems with the experiment. The distribution of the gas phase was heterogeneous with CO₂ gas pockets forming below low permeability layers, as evidenced by surface GPR, permeameter tests, and grain size analyses. These gas pockets accumulated until sufficient pressure built up to overcome the displacement pressure of these lower permeability layers. At this point there is evidence of CO₂ breakthrough in the cross-borehole GPR data and physical observations of gas bubbles at the water table. These observations are consistent with previous investigations, which indicate that although the Borden aquifer is homogeneous, distinct horizontal layering is present with sufficient variations in permeability/displacement pressure to trap and cause some lateral spreading of a gas phase. The evidence of channeling and the impact of heterogeneities on gas distribution are consistent with air sparging studies.

Sites where 2-chlorobutadiene-1,3 (chloroprene) and 2,3-dichlorobutadiene-1,3 (DCBD) are synthesized for use in chlorobutyl rubber have the potential to release a mixture of at least five chlorinated butenes and butadienes including trans-1,4-dichlorobutene-2 (1,4-DCB-2), 3,4-dichlorobutene-1 (3,4-DCB-1), 2,3,4-trichlorobutene-1 (2,3,4-TCB-1), chloroprene and DCBD into the groundwater environment. Granular iron has been shown to be effective in the remediation of groundwater contaminated with chlorinated organic compounds by reductive dechlorination. To evaluate the possibility of using granular iron in the remediation of the above contaminants a series of batch and column experiments were conducted at the laboratory scale. Chlorine mass balance calculations showed that each compound, with the exception of DCBD, could be fully dechlorinated by the use of granular iron. Kinetic data and proposed reaction pathways, however, suggest that DCBD can also be fully dechlorinated by granular iron. Normalization of observed pseudo-first-order reaction half-lives indicated that compounds were degrading much slower in batch experiments than in column experiments. This, along with the observation that temperature did not affect degradation in batch experiments, led to the conclusion that mass transport to the iron surfaces was limiting degradation rates in batch experiments. Results showed that the three chlorinated butenes degraded much faster (normalized column half-lives ranged from 1.6 to 5.2 min) than the two chlorinated butadienes (normalized column half-lives ranged from 115 to 197 min). Chlorinated and non-chlorinated intermediates were identified. It was determined that all contaminants degrade to 1,3-butadiene as a reaction intermediate which then degraded to a mixture of non-harmful end products consisting of 1-butene, cis-2-butene, trans-2-butene and n-butane. The reaction pathway from 1,4-DCB-2 to 1,3-butadiene was proposed to be a reductive elimination similar to reductive β-elimination. 3,4-DCB-1 and 2,3,4-TCB-1 were proposed to undergo reductive β-elimination reactions resulting in 1,3-butadiene and chloroprene intermediates, respectively. Degradation of chloroprene and DCBD occurred via hydrogenolysis pathways while 1,3-butadiene underwent catalytic hydrogenation resulting in the observed end products. The results suggest that granular iron may be an effective treatment for groundwater contaminated with these compounds.

An emplaced source of coal tar creosote within the sandy Borden research aquifer has provided an opportunity to document the long term (5140 days) natural attenuation for this complex mixture. Plumes of dissolved chemicals were produced by the essentially horizontal groundwater flowing at about 9 cm/day. Eleven chemicals were extensively sampled seven times using a monitoring network of ~280 14-point multilevel samplers. A model of source dissolution using Raoult’s Law adequately predicted the dissolution of nine of eleven compounds analysed. Mass transformation has limited the extent of the plumes as groundwater flowed more than 500 m yet the plumes are no longer than 50 m. Phenol and xylenes were removed and naphthalene was attenuated from its maximum extent on day 1357. Some compound plumes reached an apparent steady state and the plumes of other compounds (dibenzofuran and phenanthrene) are expected to continue to expand due to an increasing mass flux and limited degradation potential. Biotransformation is the major process controlling natural attenuation at the site. The greatest organic mass loss is associated with the high solubility compounds. However, the majority of the mass loss for most compounds has occurred in the source zone. Oxygen is the main electron acceptor yet the amount of organics lost cannot be accounted for by aerobic mineralization or partial mineralization alone. After 10 years the source zone was treated with permanganate in situ to reduce the flux of contaminants into the dissolved plume and to permit natural attenuation to further reduce the plume extent. A sufficient mass of permanganate was injected to oxidize ~10% of the residual source. Laboratory experiments demonstrated that eight of ten of the study compounds were readily oxidized by permanganate. Once treated oxidized compounds displayed a reduced plume mass and mass discharge while they migrated through the monitoring network. Once beyond the monitoring network the mass discharge and plume mass of these compounds returned to pre-treatment trends. Non-reactive compounds displayed no significant decrease in mass discharge or plume mass. Overall the partial in situ chemical oxidation of the coal tar creosote source produced no long-term effect on the dissolved plumes emanating from the source.

Air sparging is a technique used to remediate gasoline contamination. In sparging, air is injected below the target zone and removes contamination via two separate mechanisms; volatilization and biodegradation. In volatilization, the air contacts the contamination as it moves upward. The contaminant will partition to the vapor phase based on its volatility and will be removed as the air reaches the atmosphere. For biodegradation, the oxygen in the airstream is used for microbial activity. Pulsed air sparging, otherwise known as pulsed biosparging, has been found to be more effective than continuous air sparging. Pulsed biosparging enhances treatment because it induces groundwater movement and mixing. The general mechanisms for treatment of gasoline sources using air sparging are relatively well characterized. However, air flow through the subsurface and the total hydrocarbon mass lost are difficult to predict and quantify. This project was intended to quantify the mass lost through volatilization and through biodegradation at the E10 gasoline source using pulsed biosparging, and to determine the effect of the source zone removal on downgradient dissolved BTEX concentrations. The remedial system consisted of two major components: the air sparging system, with three injection points; and a soil gas collection system. The soil gas collection system was comprised of an airtight box that covered the source area and the monitoring wells upgradient and downgradient of the source. Off-gas from the soil gas collection system was monitored continuously using a PID. The off-gas was also sampled frequently for BTEX, pentane, and hexane to determine the hydrocarbon mass removed; and for O2 and CO2 to determine biodegradation rates. The remedial system ran for approximately 280 hours over 33 days. Of the estimated 22.3 kg of gasoline residual in the source zone, 4.6 kg or 21% of the residual was removed via volatilization and 4.9 kg or 22% of the residual was removed via biodegradation. Leakage outside the system was estimated at less than 0.1% of the total mass. Groundwater samples were collected when the last sparged air was calculated to arrive at the row 2 downgradient fence. The average BTEX groundwater concentration after sparging was 40% of the pre-sparging concentration. The benzene mass discharge decreased 27%, the ethylbenzene mass discharge decreased 65%, the p/m-xylene mass discharge decreased 6%, and the o-xylene mass discharge decreased 5%. The mass discharge for naphthalene and TMB isomers increased 19%. However, these values fit in with long-term groundwater concentration trends. Additional sampling is recommended to determine if the sparging made a significant impact on mass discharge leaving the source.

The purpose of this study was two-fold. First the researcher set out to determine if phonemic awareness skills improved for first grade students of teachers who used the Lindamood Phoneme Sequencing Program (LiPS; Lindamood & Lindamood, 1998). Second, an attempt was made to determine if there was a relationship between reading improvement in decoding and teacher level variables (i.e., perception of their knowledge of the LiPS program (Lindamood & Lindamood, 1998), and relevant demographic variables).<p>Students scores based on the Learning Disabilities Working Committee Kindergarten screening tool (LDWC, 2005) were compared to their respective scores on the Learning Disabilities Working Committee Grade One screening tool (LDWC, 2002). Comparison of progress for all students were evaluated as well as assessment of progress for students deemed at risk (below the 25th percentile) of reading failure compared to those not at risk (above the 25th percentile). Teachers perceptions of the critical elements of the LiPS program (Lindamood & Lindamood, 1998) and demographic information were collected. The teacher level variables gathered from this survey (i.e., teaching experience, formal training, knowledge, or skill level in program delivery) were correlated to students scores on the screening tools.<p>Results revealed that teacher demographics, such as teaching experience, specialized training, and intensity of instructional approach are related to student reading achievement in decoding; however, no clearly defined relationship was found between teachers perceptions of the LiPS program (Lindamood & Lindamood, 1998) and student achievement. Paired-sample t-tests were also used to determine if statistically significant differences existed between the means of phonemic identity, phonemic blending, and letter/sound identification between Kindergarten and Grade One. Even though statistically significant results were noted, consideration of the actual change in mean scores and effect size suggested if a practical significance existed. Results indicated that gains were made by students in phonemic awareness and letter/sound correspondence; however, greater gains were noted for students deemed at-risk whose teachers used the LiPS program (Lindamood & Lindamood, 1998).