bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Nutrient Amendments on Indigenous Hydrocarbon Biodegradation in Oil‐Contaminated Beach Sediments
Authors: Xu Ran , Obbard Jeffrey P. 
Published: June 2010

ABSTRACTNutrient amendment to oil‐contaminated beach sediments is a critical factor for the enhancement of indigenous microbial activity and biodegradation of petroleum hydrocarbons in the intertidal marine environment. In this study, we investigated the stimulatory effect of the slow‐release fertilizers Osmocote (Os; Scotts, Marysville, OH) and Inipol EAP‐22 (Ip; ATOFINA Chemicals, Philadelphia, PA) combined with inorganic nutrients on the bioremediation of oil‐spiked beach sediments using an open irrigation system with artificial seawater over a 45‐d period. Osmocote is comprised of a semipermeable membrane surrounding water‐soluble inorganic N, P, and K. Inipol, which contains organic N and P, has been used for oil cleanup on beach substrate. Nutrient concentrations and microbial activity in sediments were monitored by analyzing sediment leachates and metabolic dehydrogenase activity of the microbial biomass, respectively. Loss of aliphatics (n‐C12 to n‐C33, pristane, and phytane) was significantly greater (total loss between 95 and 97%) in oil‐spiked sediments treated with Os alone or in combination with other nutrient amendments, compared with an unamended oil‐spiked control (26% loss) or sediments treated with the other nutrient amendments (28–65% loss). A combination of Os and soluble nutrients (SN) was favorable for the rapid metabolic stimulation of the indigenous microbial biomass, the sustained release of nutrients, and the enhanced biodegradation of petroleum hydrocarbons in leached, oil‐contaminated sediments.
RDX Loss in a Surface Soil under Saturated and Well Drained Conditions
Authors: Ringelberg D. B. , Reynolds C. M. , Walsh M. E. , Jenkins T. F. 
Published: June 2010

ABSTRACTOn military training ranges, low‐order, incomplete detonations deposit RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine) into surface soils. In this study, we evaluated RDX biodegradation in surface soils obtained from a military training range in Alaska. Two factors were compared: (i) soil water potential during the incubations; and (ii) the use of acetonitrile (ACN) as an RDX carrier to spike samples. Organic solvents have been used in laboratory studies to dissolve slightly water‐soluble contaminants before addition to soil. We added ACN to obtain final soil ACN concentrations of 0 mg kg−1 (0%), 1000 mg kg−1 (0.1%) and 10 000 mg kg−1 (1%). We then compared RDX attenuation in the soil under saturated and unsaturated conditions. RDX fell below the limit of detection within 3 wk of study initiation under the saturated condition. A maximum degradation rate of 0.15 mg RDX L−1 d−1 was measured. Under the unsaturated condition, 42% of the original RDX was still present at study termination (5 wk). The addition of acetonitrile at 0.1 or 1.0% had no affect on RDX loss in the saturated soil. In the unsaturated soil, however, ACN at 1.0% inhibited RDX loss by as much as 25%. These findings indicate that soil water potential and carrier solvent concentrations can impact the rate and extent to which RDX is attenuated in a surface soil.
Phosphogypsum Amendment Effect on Radionuclide Content in Drainage Water and Marsh Soils from Southwestern Spain
Authors: El‐Mrabet Rachid , Abril José‐María , Periáñez Raúl , Manjón Guillermo , García‐Tenorio Rafael , Delgado Antonio , Andreu Luis 
Published: June 2010

ABSTRACTPhosphogypsum (PG) is a residue of the phosphate fertilizer industry that has relatively high concentrations of 226Ra and other radionuclides. Thus, it is interesting to study the effect of PG applied as a Ca amendment on the levels and behavior of radionuclides in agricultural soils. A study involving treatments with 13 and 26 Mg ha−1 of PG and 30 Mg ha−1 of manure was performed, measuring 226Ra and U isotopes in drainage water, soil, and plant samples. The PG used in the treatment had 510 ± 40 Bq kg−1 of 226Ra. The 226Ra concentrations in drainage waters from PG‐amended plots were similar (between 2.6 and 7.2 mBq L−1) to that reported for noncontaminated waters. Although no significant effect due to PG was observed, the U concentrations in drainage waters (200 mBq L−1 for 238U) were one order of magnitude higher than those described in noncontaminated waters. This high content in U can be ascribed to desorption processes mainly related to the natural adsorbed pool in soil (25 Bq kg−1 of 238U). This is supported by the 234U to 238U isotopic ratio of 1.16 in drainage waters versus secular equilibrium in PG and P fertilizers. The progressive enrichment in 226Ra concentration in soils due to PG treatment cannot be concluded from our present data. This PG treatment does not determine any significant difference in 226Ra concentration in drainage waters or in plant material [cotton (Gossipium hirsutum L.) leaves]. No significant levels of radionuclides except 40K were found in the vegetal tissues.
Impact of Sample Preparation on Mineralogical Analysis of Zero‐Valent Iron Reactive Barrier Materials
Authors: Phillips D. H. , Gu B. , Watson D. B. , Roh Y. 
Published: June 2010

ABSTRACTPermeable reactive barriers (PRBs) of zero‐valent iron (Fe0) are increasingly being used to remediate contaminated ground water. Corrosion of Fe0 filings and the formation of precipitates can occur when the PRB material comes in contact with ground water and may reduce the lifespan and effectiveness of the barrier. At present, there are no routine procedures for preparing and analyzing the mineral precipitates from Fe0 PRB material. These procedures are needed because mineralogical composition of corrosion products used to interpret the barrier processes can change with iron oxidation and sample preparation. The objectives of this study were (i) to investigate a method of preparing Fe0 reactive barrier material for mineralogical analysis by X‐ray diffraction (XRD), and (ii) to identify Fe mineral phases and rates of transformations induced by different mineralogical preparation techniques. Materials from an in situ Fe0 PRB were collected by undisturbed coring and processed for XRD analysis after different times since sampling for three size fractions and by various drying treatments. We found that whole‐sample preparation for analysis was necessary because mineral precipitates occurred within the PRB material in different size fractions of the samples. Green rusts quickly disappeared from acetone‐dried samples and were not present in air‐dried and oven‐dried samples. Maghemite/magnetite content increased over time and in oven‐dried samples, especially after heating to 105°C. We conclude that care must be taken during sample preparation of Fe0 PRB material, especially for detection of green rusts, to ensure accurate identification of minerals present within the barrier system.
Treatment of Contaminated Soil with Phosphorus and Manganese Oxide Reduces Lead Absorption by Sprague–Dawley Rats
Authors: Hettiarachchi Ganga M. , Pierzynski Gary M. , Oehme Fredrick W. , Sonmez Osman , Ryan James A. 
Published: June 2010

ABSTRACTThis study was conducted to determine the extent of Pb absorption into young rats (Rattus norvegicus var. Sprague–Dawley) fed untreated Pb‐contaminated soil or Pb‐contaminated soil treated with two different sources of P and P + Mn oxide. Data were compared from an in vitro, physiologically based extraction test (PBET) with the animal data to support the validity of the in vitro test to assess bioavailable Pb from a treated Pb‐contaminated soil. Soil with a total Pb concentration of 2290 mg kg−1 was used. Rats were fed 19 different test diets for 21 consecutive days. The test diets represented 95 g AIN93G rat meal kg−1 diet with varying proportions of silica sand or soil to provide low, medium, or high doses of Pb from either Pb acetate, treated, or untreated soil. Blood, liver, kidney, and bone Pb concentrations were examined. For all four tissues, Pb concentrations for the Pb acetate groups were significantly higher than concentrations for all the soil groups. In general, either triple superphosphate (TSP) or phosphate rock (PR) treatments resulted in significant reductions in tissue Pb concentrations compared with untreated soil. Blood and kidney Pb concentrations for the PR + Mn oxide group were significantly lower than those of the PR group at the low and high doses. Relative bioavailability of Pb, as measured in all tissues, was significantly reduced when comparing untreated with amended soil. Correlation between the in vitro and in vivo tests, based on bone and liver tissue, showed that the in vitro test is successful at predicting Pb bioavailability.
Dissolved Organic Carbon Dynamics in a Riparian Aquifer
Authors: Jacinthe P.‐A. , Groffman P. M. , Gold A. J. 
Published: June 2010

ABSTRACTThe capacity of riparian soils to remove nitrate (NO−3) from ground water is well established, but the effects of ground water NO−3‐enrichment on C dynamics are not well studied. We incubated horizontal cores of aquifer material extracted from beneath moderately well‐drained (MWD) and poorly drained (PD) soils in a riparian forest in Rhode Island, USA for 132 d, and dosed (flow rate, 170 mL d−1; dissolved O2, 2 in PD and 5 mg L−1 in MWD cores) with ground water amended with either Br−, Br− + NO−3 (10 mg N L−1), or Br− + NO−3 + DOC (20 mg C L−1). The DOC was extracted from forest floor material and added during the first 56 d of the experiment. Addition of NO−3 had limited effect on CO2 production while DOC amendment had a significant effect in the PD but not in the MWD mesocosms. Total CO2 production (mg CO2–C kg−1 soil) was 6.3, 7.0, and 10.1 in the PD and 3.6, 4.0, and 4.5 in the MWD cores amended with Br−, Br− + NO−3, and Br− + NO−3 + DOC, respectively. Carbon balance (Cbal = DOCin − (DOCout + CO2–C) showed a net C retention of 8.0 mg C kg−1 soil in the DOC‐amended MWD cores (equivalent to 50% of the DOC added), and a net C loss of 8.3 mg C kg−1 soil in similarly treated PD cores. The lack of C retention in the PD cores was ascribed to reductive dissolution of minerals implicated in DOC sorption. These findings underscore that there is marked variation in C dynamics in riparian aquifers that has the potential to influence the fate of NO3− and DOC in the landscape.
Role of Active Floodplains for Nutrient Retention in the River Rhine
Authors: Venterink H. Olde , Wiegman F. , Van der Lee G. E. M. , Vermaat J. E. 
Published: June 2010

ABSTRACTWe evaluated the importance of floodplains for nutrient retention in two distributaries of the river Rhine (Waal and IJssel) by monitoring N and P retention in a body of water during downstream transport. We hypothesized that (i) retention of P is much larger than retention of N and (ii) nutrient retention increases with an increasing amount of the discharge flowing through floodplains (QF). The second hypothesis was tested by comparing retention between the rivers Waal (low QF) and IJssel (high QF), as well as at different discharges. Total nitrogen (TN) did not decrease significantly during downstream transport in both rivers, whereas 20 to 45% of total phosphorus (TP) disappeared during transport in the river IJssel. This difference between N and P retention—supporting the first hypothesis—was probably caused by differences in sedimentation through a much lower proportion of N adsorbed to particles than of P (2–3% of N vs. 50–70% of P). Phosphorus retention was only observed in the IJssel and not in the Waal, and absolute P retention (g P s−1 km−1) in the IJssel increased with increasing QF The second hypothesis was, nevertheless, not fully supported, because the percentage P retention (% of P load) decreased (instead of increased) with increasing QF. The percentage P retention increased with decreasing river depth and flow velocity; it seemed related to the efficiency of sediment trapping.
Nutrient and Sediment Removal by a Restored Wetland Receiving Agricultural Runoff
Authors: Jordan Thomas E. , Whigham Dennis F. , Hofmockel Kirsten H. , Pittek Mary A. 
Published: June 2010

ABSTRACTFew studies have measured removal of pollutants by restored wetlands that receive highly variable inflows. We used automated flow‐proportional sampling to monitor the removal of nutrients and suspended solids by a 1.3‐ha restored wetland receiving unregulated inflows from a 14‐ha agricultural watershed in Maryland, USA. Water entered the wetland mainly in brief pulses of runoff, which sometimes exceeded the 2500‐m3water holding capacity of the wetland. Half of the total water inflow occurred in only 24 days scattered throughout the two‐year study. Measured annual water gains were within 5% of balancing water losses. Annual removal of nutrients differed greatly between the two years of the study. The most removal occurred in the first year, which included a three‐month period of decreasing water level in the wetland. In that year, the wetland removed 59% of the total P, 38% of the total N, and 41% of the total organic C it received. However, in the second year, which lacked a drying period, there was no significant (p> 0.05) net removal of total N or P, although 30% of the total organic C input was removed. For the entire two‐year period, the wetland removed 25% of the ammonium, 52% of the nitrate, and 34% of the organic C it received, but there was no significant net removal of total suspended solids (TSS) or other forms of N and P. Although the variability of inflow may have decreased the capacity of the wetland to remove materials, the wetland still reduced nonpoint‐source pollution.
Growth and Yield Responses of Potato to Mixtures of Carbon Dioxide and Ozone
Authors: Heagle A. S. , Miller J. E. , Pursley W. A. 
Published: June 2010

ABSTRACTElevated carbon dioxide (CO2) concentrations in the atmosphere can stimulate plant growth and yield, whereas ground‐level ozone (O3) concentrations cause the opposite effect in many areas of the world. Recent experiments show that elevated CO2 can protect some plants from O3 stress, but this has not been tested for most crop species. Our objective was to determine if elevated CO2 protects Irish potato (Solanum tuberosum L.) from foliar injury and suppression of growth and yield caused by O3 An O3–resistant cultivar (Superior) and an O3–sensitive cultivar (Dark Red Norland) were exposed from within 10 d after emergence to maturity to mixtures of three CO2 and three O3 treatments in open‐top field chambers. The three CO2 treatments were ambient (370 μL L−1) and two treatments with CO2 added to ambient CO2 for 24 h d−1 (540 and 715 μL L−1). The O3 treatments were charcoal‐filtered air (15 nL L−1), nonfiltered air (45 nL L−1), and nonfiltered air with O3 added for 12 h d−1 (80 nL L−1). Elevated O3 and CO2 caused extensive foliar injury of Dark Red Norland, but caused only slight injury of Superior. Elevated CO2 increased growth and tuber yield of both cultivars, whereas elevated O3 generally suppressed growth and yield, mainly of Dark Red Norland. Elevated CO2 appeared to protect Dark Red Norland from O3–induced suppression of shoot, root, and tuber weight as measured at midseason but did not protect either cultivar from O3 stress at the final harvest. The results further illustrate the difficulty in predicting effects of O3 + CO2 mixtures based on the effects of the individual gases.
Removal of Selenate in Simulated Agricultural Drainage Water by a Rice Straw Bioreactor Channel System
Authors: Zhang Yiqiang , Frankenberger William T. 
Published: June 2010

ABSTRACTRemoval of selenium (Se) from agricultural drainage water is important in protecting wetland wildlife. Three flow‐through bioreactor channel systems (BCSs), each with three channels filled with rice (Oryza sativa L.) straw, were set in the laboratory to determine removal of selenate [Se(VI)] (1020 μg L−1) from drainage water with a salinity of 10.4 dS m−1, a pH of 8.1, and a nitrate NO−3 range of 0 to 100 mg L−1 Results showed that the rice straw effectively reduced Se(VI) during 122 to 165 d of the experiments. Calculation of Se mass in the three BCSs showed that 89.5 to 91.9% of the input Se(VI) was reduced to red elemental Se [Se(0)], where 96.6 to 98.2% was trapped in the BCSs. Losses of each gram of rice straw were almost equal to the removal of 1.66 mg of Se from the drainage water as a form of red Se(0), indicating that rice straw is a very effective organic source for removing Se(VI) from drainage water.
The Role of Nitrilotriacetate in Copper Uptake by Tobacco
Authors: Wenger K. , Gupta S. K. , Furrer G. , Schulin R. 
Published: June 2010

ABSTRACTIn growth chamber experiments we studied the effect of nitrilotriacetate (NTA) on Cu uptake by tobacco (Nicotiana tabacum L.). Plants were exposed for 6 d to 126 μM Cu and 500 μM NTA in nutrient solutions without and with 10 g L−1 montmorillonite. Approximately seven times less Cu was dissolved in the montmorillonite solutions than in the nutrient solutions alone. In the absence of NTA, montmorillonite effectively competed with plant roots for Cu, although Cu remained bound to the roots. Nitrilotriacetate increased Cu uptake and translocation into shoots of tobacco by a factor of 3.5 from the nutrient solution and by a factor of 26 from the montmorillonite nutrient solution. Neither growth reduction nor any other visible sign of Cu toxicity was found in the presence of NTA with Cu concentrations of 190 mg kg−1 in the shoots. In the absence of NTA, high Cu concentrations in root samples led to a brownish discoloration of the roots.
Assessing the Application of an Additive Model to Estimate Toxicity of a Complex Effluent
Authors: Ross Kirstin E. , Bidwell Joseph R. 
Published: June 2010

ABSTRACTA number of industries monitor levels of chemicals in their effluent, but few have undertaken prolonged biological monitoring of this wastewater. The focus of the present study was to determine whether past chemical data for effluent from a lead smelter could be used to estimate its past toxicity. Since the interactive effects of metals in effluents are often assumed to be additive, it was hypothesized that an additive model, 100/[Σ(metal concentration in effluent/EC50 for individual metal)], could be used to generate an EC50 from chemical data (where EC50 is the concentration of test material that affects 50% of the test organisms). To test the approach, a larval development toxicity test with the marine polychaete, Galeolaria caespitosa, was used to test 26 separate samples of effluent from a lead smelter, generating empirical EC50 values. EC50 values for each individual metal in the effluent were also generated using the larval development toxicity test. The concentrations of trace metals in each effluent sample were determined and, using the additive model, EC50 values were calculated. For the majority of effluent samples tested, the additive model underestimated toxicity, suggesting the presence of additional unidentified contaminants in the effluent samples. Additionally, a nonlinear rather than linear regression curve was found to best describe the relationship between the model and empirically derived EC50 values. This relationship was then used to estimate past trends in toxicity of the smelter effluent. Forty‐eight percent of the variability in measured toxicity was explained by the model, with the model underestimating toxicity in the majority of samples.
Sorption and Desorption of Cadmium by Different Fractions of Biosolids‐Amended Soils
Authors: Hettiarachchi Ganga M. , Ryan James A. , Chaney Rufus L. , La Fleur Cherie M. 
Published: June 2010

ABSTRACTTo evaluate the importance of both the inorganic and organic fractions in biosolids on Cd chemistry, a series of Cd sorption and desorption batch experiments (at pH 5.5) were conducted on different fractions of soils from a long‐term field experimental site. The slope of the Cd sorption isotherm increased with rate of biosolids and was different for the different biosolids. Removal of organic carbon (OC) reduced the slope of the Cd sorption isotherm but did not account for the observed differences between biosolids‐amended soils and a control soil, indicating that the increased adsorption associated with biosolids application was not limited to the increased OC from the addition of biosolids. Removal of both OC and Fe/Mn further reduced the slopes of Cd sorption isotherms and the sorption isotherm of the biosolids‐amended soil was the same as that of the control, indicating both OC and Fe/Mn fractions added by the biosolids were important to the increased sorption observed for the biosolids‐amended soil samples. Desorption experiments failed to remove from 60 to 90% of the sorbed Cd. This “apparent hysteresis” was higher for biosolids‐amended soil than the control soil. Removal of both OC and Fe/Mn fractions was more effective in removing the observed differences between the biosolids‐amended soil and the control than either alone. Results show that Cd added to biosolids‐amended soil behaves differently than Cd added to soils without biosolids and support the hypothesis that the addition of Fe and Mn in the biosolids increased the retention of Cd in biosolids‐amended soils.
Kerogen in Aquifer Material and Its Strong Sorption for Nonionic Organic Pollutants
Authors: Ran Yong , Xiao Baohua , Huang Weilin , Peng Ping'an , Liu Dehan , Fu Jiamo , Sheng Guoying 
Published: June 2010

ABSTRACTSorption of organic pollutants by subsurface materials has been found to not only correlate with the total organic carbon (TOC) content, but also depend on the types of soil and sediment organic matter (SOM). Characterization of geochemically heterogeneous SOM is key to elucidating sorption mechanisms and predicting pollutant transport in ground water systems. In this study, kerogen, a nonextractable organic material, was isolated with an acid demineralization procedure from a sandy aquifer material (Borden, Ontario, Canada) having a TOC content of approximately 0.021% (w/w). Petrographical examinations reveal that the kerogen has three major types of macerals including bituminite (Kerogen Type I and II), vitrinite (Type III), and fusinite (Type IV or charred kerogen). The solid‐state 13C nuclear magnetic resonance (NMR) spectrum shows two dominant peaks, aliphatic and aromatic carbons, for the isolated material. Sorption isotherms measured using phenanthrene, naphthalene, 1,3,5‐trichlorobenzene (TCB), and 1,2‐dichlorobenzene (DCB) as sorbates showed that both the isolated kerogen and the original sand exhibited nonlinear sorption and that the phenanthrene and TCB isotherms measured for the kerogen material are more nonlinear than the respective isotherms for the original sand. The single‐point organic carbon–normalized sorption capacity measured for the isolated kerogen can be several times greater than that measured for the original sand for a given sorbate. The study suggests that kerogen plays a major role in overall sorption isotherm nonlinearity and could yield higher‐than‐predicted sorption capacities for the subsurface material even though the content of this organic material is very low.