Jeffrey W. Talley

Succession of Phenotypic, Genotypic, and Metabolic Community Characteristics during In Vitro Bioslurry Treatment of Polycyclic Aromatic Hydrocarbon-Contaminated Sediments

ABSTRACT Dredged harbor sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) was removed from the Milwaukee Confined Disposal Facility and examined for in situ biodegradative capacity. Molecular techniques were used to determine the successional characteristics of the indigenous microbiota during a 4-month bioslurry evaluation. Ester-linked phospholipid fatty acids (PLFA), multiplex PCR of targeted genes, and radiorespirometry techniques were used to define in situ microbial phenotypic, genotypic, and metabolic responses, respectively. Soxhlet extractions revealed a loss in total PAH concentrations of 52%. Individual PAHs showed reductions as great as 75% (i.e., acenapthene and fluorene). Rates of 14C-PAH mineralization (percent/day) were greatest for phenanthrene, followed by pyrene and then chrysene. There was no mineralization capacity for benzo[a]pyrene. Ester-linked phospholipid fatty acid analysis revealed a threefold increase in total microbial biomass and a dynamic microbial community composition that showed a strong correlation with observed changes in the PAH chemistry (canonicalr2 of 0.999). Nucleic acid analyses showed copies of genes encoding PAH-degrading enzymes (extradiol dioxygenases, hydroxylases, and meta-cleavage enzymes) to increase by as much as 4 orders of magnitude. Shifts in gene copy numbers showed strong correlations with shifts in specific subsets of the extant microbial community. Specifically, declines in the concentrations of three-ring PAH moieties (i.e., phenanthrene) correlated with PLFA indicative of certain gram-negative bacteria (i.e., Rhodococcus spp. and/or actinomycetes) and genes encoding for naphthalene-, biphenyl-, and catechol-2,3-dioxygenase degradative enzymes. The results of this study suggest that the intrinsic biodegradative potential of an environmental site can be derived from the polyphasic characterization of the in situ microbial community.

Effect of NOM on Arsenic Adsorption by TiO2 in Simulated As(III)-Contaminated Raw Waters

The effect of natural organic matter (NOM) on arsenic adsorption by a commercial available TiO(2) (Degussa P25) in various simulated As(III)-contaminated raw waters was examined. Five types of NOM that represent different environmental origins were tested. Batch adsorption experiments were conducted under anaerobic conditions and in the absence of light. Either with or without the presence of NOM, the arsenic adsorption reached steady-state within 1h. The presence of 8 mg/L NOM as C in the simulated raw water, however, significantly reduced the amount of arsenic adsorbed at the steady-state. Without NOM, the arsenic adsorption increased with increasing solution pH within the pH range of 4.0-9.4. With four of the NOMs tested, the arsenic adsorption firstly increased with increasing pH and then decreased after the adsorption reached the maximum at pH 7.4-8.7. An appreciable amount of arsenate (As(V)) was detected in the filtrate after the TiO(2) adsorption in the simulated raw waters that contained NOM. The absolute amount of As(V) in the filtrate after TiO(2) adsorption was pH dependent: more As(V) was presented at pH>7 than that at pH<7. The arsenic adsorption in the simulated raw waters with and without NOM were modelled by both Langmuir and Frendlich adsorption equations, with Frendlich adsorption equation giving a better fit for the water without NOM and Langmuir adsorption equation giving a better fit for the waters with NOM. The modelling implies that NOM can occupy some available binding sites for arsenic adsorption on TiO(2) surface. This study suggests that in an As(III)-contaminated raw water, NOM can hinder the uptake of arsenic by TiO(2), but can facilitate the As(III) oxidation to As(V) at TiO(2) surface under alkaline conditions and in the absence of O(2) and light. TiO(2) thus can be used in situ to convert As(III) to the less toxic As(V) in NOM-rich groundwaters.

Influence of ionic strength, electrolyte type, and NOM on As(V) adsorption onto TiO2.

As(V) adsorption onto a commercially available TiO2 (Degussa P25) in NaCl or NaClO4 at various concentrations (0.001–0.1 M) was investigated. The effect of natural organic matter (NOM) on As(V) removal through the adsorption by TiO2 was also examined. In either electrolyte, As(V) adsorption onto TiO2 increased with the increase of ionic strength under alkaline conditions (pH 7.0–11.0). Under acidic conditions (pH 4.0–6.0), the adsorption of As(V) onto TiO2 was insensitive to ionic strength in NaClO4 electrolyte but decreased with increasing ionic strength in NaCl electrolyte. The presence of 2–15 mg/L NOM as C significantly decreased the fraction of As(V) adsorbed onto TiO2 at pH 6.0 regardless of the initial As(V) concentration (1–15 μM). The measurement of zeta potential of TiO2 with and without As(V) suggests that the presence of As(V) can shift the point of zero charge (pHpzc) of TiO2 to a lower pH value. The overall data presented in this study suggest that As(V) can form both inner-sphere and outer-sphere complexes on TiO2 surface, and NOM is an important factor controlling As(V) adsorption onto TiO2.

Copper Doping Improves Hydroxyapatite Sorption for Arsenate in Simulated Groundwaters

Hydroxyapatite (HAP) has been widely used to immobilize many cationic heavy metals in water and soils. Compared with its strong sorption for metal cations, the abilities of HAP to sorb metal anions, such as arsenic, are less significant. Improving HAP sorption for anionic arsenic species is important for expanding its application potential because the presence of arsenic in the environment has raised serious health concerns and there is need for cost-effective remediation methods. In this work, we report an innovative method of copper doping to improve a synthetic HAP sorption for arsenate, which is a primary aqueous arsenic species, in simulated groundwaters. The undoped HAP and copper doped HAP (CuHAP) were characterized with XRD, FTIR, N(2) adsorption, and SEM, and then evaluated as sorbents for arsenate removal tests. The experimental results suggest that copper doping changed the morphology and increased the surface area of HAP. The CuHAP sorbed 1.6-9.1x more arsenate than the undoped HAP did in a simulated groundwater at pH of 7.7-8.0. The improved arsenate sorption is presumably due to the increase in surface area of HAP as a result of copper doping. In addition to the copper doping level, the arsenate sorption to HAP and CuHAP can also be increased with increasing water pH and calcium concentration. The experimental data indicate that sorbent dissolution is an important factor governing arsenate sorption to HAP and CuHAP.

Bioremediation of Recalcitrant Compounds

Introduction to Recalcitrant Compounds J.W. Talley Toxicological Exposure of Bound Recalcitrant Compounds H. Fredrickson, J.S. Furey, and J.W. Talley Roadblocks to the Implementation of Biotreatment Strategies J.W. Talley The Federal Integrated Biotreatment Research Consortium (Flask to Field) J.W. Talley Chlorinated Solvent Contaminated Soils and Groundwater: Field Application of the Solvent Extraction Residual Biotreatment Technology G. Sewell, S.C. Mravik, A.L. Wood, M. Annable, R. Sillan, and K. Warner Enhancing PCB Bioremediation J.M. Tiedje, T.V. Tsoi, K.D. Pennell, L.D. Hansen, A. Wani, and Desiree P. Howell Polycyclic Aromatic Hydrocarbons (PAHs): Improved Land Treatment with Bioaugmentation H. Prichard, J. Jones-Meehan, C. Nestler, Dr. Lance D. Hansen, William Straube, Dr. W. Jones, Dr. J. Hind, and J.W. Talley Future Needs for Research and Development J.W. Talley. Index

Model verification of thermal programmed desorption-mass spectrometry for estimation of release energy values for polycyclic aromatic hydrocarbons on mineral sorbents†

The physical availability of organic compounds in soil and sediment strongly influences their bioavailability and toxicity. Previous work has indicated that physical availability changes throughout the processes of aging and treatment and that it can be linked to the energy required to release the compound from its sorbent matrix, with a higher energy indicating a more tightly bound compound. This study focused on determining release energy values for various mineral geosorbents (glass beads, sand, and kaolin) contaminated with a 16 polycyclic aromatic hydrocarbon (PAH) mixture. The sorbents were analyzed using thermal program desorption/mass spectrometry (TPD/MS) and the release energy values were calculated from the resulting thermograms utilizing a nonlinear fit of the analytical solution to a simplified version of the Polanyi-Wigner equation. This solution method resulted in a series of combinations of values for the pre-exponential factor (v) and release energy (E) that produced desorption rate curves with similar errors when fit to actual data sets. These combinations can be viewed as an error surface, which clearly shows a valley of minimum error values spanning the range of both E and v. This indicates that this method may not provide a unique set of E- and v-values and suggests that the simplified version of the Polanyi-Wigner equation cannot be used to determine release energy based on TPD data alone.

Hydrolysis of the soluble fluorescent molecule carboxyumbelliferyl-beta-d-glucuronide by E. coli beta-glucuronidase as applied in a rugged, in situ optical sensor

Techniques utilizing β-glucuronidase (GUS) activity as an indicator of Escherichia coli (E. coli) presence use labeled glucuronides to produce optical signals. Carboxyumbelliferyl-β-d-glucuronide (CUGlcU) is a fluorescent labeled glucuronide that is soluble and highly fluorescent at natural water pHs and temperatures and, therefore, may be an ideal reagent for use in an in situ optical sensor. This paper reports for the first time the Michaelis-Menten kinetic parameters for the binding of E. coli GUS with CUGlcU as K(m)=910 μM, V(max)=41.0 μM min(-1), V(max)/K(m) 45.0 μmol L(-1)min(-1), the optimal pH as 6.5 ± 1.0, optimal temperature as 38°C, and the Gibbs free energy of activation as 61.40 kJ mol(-1). Additionally, it was found CUGlcU hydrolysis is not significantly affected by heavy solvents suggesting proton transfer and solvent addition that occur during hydrolysis are not limiting steps. Comparison studies were made with the more common fluorescent molecule methylumbelliferyl-β-d-glucuronide (MUGlcU). Experiments showed GUS preferentially binds to MUGlcU in comparison to CUGlcU. CUGlcU was also demonstrated in a prototype optical sensor for the detection of E. coli. Initial bench testing of the sensor produced detection of low concentrations of E. coli (1.00 × 10(3)CFU/100mL) in 230 ± 15.1 min and high concentrations (1.05×10(5)CFU/100mL) in 8.00 ± 1.01 min.