bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of Methods for Determining Elements in Solid Waste by Microwave Digestion
Authors: Binstock DA , Grohse PM , Gaskill A , Luk KK , Swift PL , Kingston HM , Sellers C
Published: March 2009

The techniques which are typically used to prepare RCRA wastes for analysis for metals and other elements are generally relatively time consuming, requiring several hours to several days to complete. They also often involve the use of acid digestions and thermal decomposition steps which may result in analyte losses, incomplete recoveries, or sample contamination. These limitations are well known to the analytical community and to the end users of these data in EPA, States, and industry. The resulting inefficiency of these techniques reduces laboratory sample throughput, drives up the cost of analytical testing, and impedes decision making. Given these concerns, the OSW Methods Section is interested in developing cost effective sample preparation techniques for metals and other elements in environmental and process waste samples. Once developed, these techniques can then be written as methods for inclusion in Test Methods for Evaluation of Solid Waste SW-846 and made available to the user community. This paper reports on the evaluation of a microwave assisted sample preparation method for determining elements in solid waste. The Method was evaluated for microwave digestion of sediments, sludges, soils, and oils.
Results of an Interlaboratory Study of ICP-AES Method 6010 with Digestion Method 3050
Authors: Hinners TA , Jones CL , Hodge VF , Schoengold DM , Biesiada JH , Starks TA , Campana JE
Published: March 2009

This interlaboratory study examined the application of inductively coupled plasma atomic emission spectroscopy (U.S. EPA Method 6010) for the determination of 23 elements in 7 solid wastes. The solid samples were digested using a nitric acid — hydrogen peroxide procedure (U.S. EPA Method 3050). The study design allowed the variability of sample preparation to be distinguished from the measurement variability. Precision and accuracy data are presented and discussed. Data obtained by inductively coupled plasma atomic emission are compared with data obtained by atomic absorption spectroscopy. Results obtained with and without the method of standard additions are subjected to statistical comparison.
Sample Preparation for the Analysis of Cyanides in Solid Wastes
Authors: Ritzert CJ
Published: March 2009

The management of cyanide bearing wastes in the environment is a major concern of both US EPA and industry. The measurement of cyanide forms in these wastes cannot be accomplished using methodology currently approved by EPA. This paper discusses cyanide measurements in terms of environmental significance with regard to decision making criteria. The recommendation is made to substitute a Weak Acid Dissociable method for the amenable cyanide by difference technology currently approved as SW846 Method 9010.
Preparation of Radioactive “Mixed” Waste Samples for Measurement of RCRA Organic Compounds
Authors: Tomkins BA , Caton JE
Published: March 2009

Radioactive “mixed” waste contains radionuclides and varying quantities of semivolatile and/or volatile organics, some or all of which may be named specifically by the RCRA. They are presently stored above-ground at great cost to the user. Analytical procedures which can identify the presence, or at least confirm the absence, of RCRA organics in radioactive waste are necessary for deciding the proper approaches for disposal.

Our general analytical strategy removes organic species in “mixed” wastes in such a way that transfer of activity is minimized. Analytical equipment and procedures listed in EPA-approved methods are used wherever possible; however, alternative procedures such as solid-phase extraction (for semivolatiles) have been evaluated as reasonable alternatives. Final quantitations are performed on the nonradioactive concentrated extract in conventional organic analytical laboratories using EPA-approved analytical methods.
Portable Test Method for the Detection of Halides in Used Oil
Authors: Minucci DA , Finch SR
Published: March 2009

EPA regulation 40 CFR 261 establishes that any used or waste oil containing greater than 1000 ppm organic chloride may have to be classified as a hazardous waste. EPA estimates that approximately 500 million gallons of used oil and 2 million tons of hazardous waste oil are burned yearly.

In response to the November 1985 rule prohibiting the burning of used oils containing greater than 1000 ppm total halogens in non-industrial burners, the Clor-D-Tect 1000™ kit was developed. This field portable test kit is based on the detection of the total amount of chlorine in an oil sample.

A complete test requires approximately 7 minutes and is ideal for on-the-spot checks by enforcement agencies as well as used oil generators, sellers, blenders and burners. This paper gives results from field studies and gives recommendations for use of the test method.
Development of an Environmental Monitoring Technique Using Synchronous Excitation (SE) Fluorescence Spectroscopy
Authors: Stainken DM , Frank U
Published: March 2009

Environmental monitoring of discharge plumes (surface and groundwater) and effluents generally involves extensive analyses which frequently employ GC, GC/MS, ICAP or AA techniques. These techniques usually require extraction procedures followed by analyses for specific analytes. When monitoring complex mixtures, these procedures can become more difficult, prone to error and limited by analytical thresholds to the ppb and ppm range. When environmental discharges occur, the dilution process exacerbates analytical problems by lowering concentrations. An alternative/supportive technique is the use of SE fluorescence spectroscopy. This technique can be used for fingerprinting effluents and contaminant mixtures in the ppt range.

An SE fluorescence technique was developed specifically for monitoring effluent from a facility manufacturing a variety of dyes and ancillary products. Prior to discharge, the effluent was treated in a biological and charcoal (PAC) waste treatment system. The effects of sampling (composite, grab), sample storage, fluorescence properties of the effluent (spectral fingerprint) and fluorescence characteristics of the effluent in ambient waters was determined. Consequently, a method was established which “fingerprints” effluent at dilutions of 1:1000, can identify effluent at dilutions of 1:4000, and has fingerprinted similar source material in a rivershed adjacent to the site. This rapid technique can be used to fingerprint and monitor a variety of environmental discharges or plumes when appropriate contaminants are present.
Establishing an Analytical Manual for Petroleum and Gasoline Products for New Jersey's Environmental Programs
Authors: Stainken DM , Miller MW
Published: March 2009

Eight New Jersey Department of Environmental Protection (DEP) Programs administer regulations concerning petroleum products. The analytical methodologies for these programs have not been codified within Federal Regulations, and several method variants exist. To assure the Department employs appropriate methods to achieve each Programs' objectives, a Committee was formed to establish a Department “Manual of Petroleum Product Analyses.” Phase I of the project determined the regulatory objectives and analytical needs of each program. In Phase II, an extensive review of currently existing or tentative methods was conducted. The methods/ standards reviewed included those of Federal and State Agency Departments, as well as American Society For Testing and Materials (ASTM), American Public Health Association (APHA), American Petroleum Institute (API), etc. Phase II consisted of a “distillation” of select methods/procedures for N.J. DEP programs and establishment of a draft “State” manual. Each method includes an introduction which details where to apply the method, and the advantages and limitations of the method. Where appropriate, additional research and development needs were identified. This manual will be included in the States' revised laboratory certification regulations which will also establish a certification category for petroleum and gasoline product analyses. Consequently, this manual will codify and standardize these procedures for New Jersey's Environmental Programs.
Direct J-R Curve Analysis: A Guide to the Methodology
Authors: Herrera R , Landes JD
Published: March 2009

A direct method for evaluating J-R curves from load displacement data is proposed. This method eliminates a need for automatic crack length monitoring equipment. The method uses the geometric normalization suggested by Ernst for deeply cracked bend specimens to develop calibration curves which relate load, displacement, and crack length. Given two of these parameters, the third can be determined from the calibration curves. These curves are developed by assuming a functional form with unknown constants and evaluating the unknowns at calibration points in the test. This method was previously proposed using a power law functional form. In this paper a more general functional form is proposed which combines a power law and straight line. The method is studied for a variety of materials and specimen sizes. From the results a recommendation is made on how to generally apply the method.
Magnetic Emission Detection of Crack Initiation
Authors: Winkler SR
Published: March 2009

A new technique has been developed to measure the onset of fracture events. Steel structures or fracture mechanics steel specimens emit magnetic signals during rapid mechanical loading and when material failure occurs. These signals can be utilized for the detection of the originating events. In particular, the initiation of crack propagation, which is of basic interest for the determination of critical material parameters in fracture mechanics, can be determined. Reported are first results and efforts to understand the origin of the signals by a comparison with fracture surface appearances from fracture mechanics specimens.
Effect of Biaxial Loading on A533B in Ductile-Brittle Transition
Authors: Garwood SJ , Davey TG , Wong YC
Published: March 2009

A series of large-scale wide plate tests have been carried out on the nuclear reactor pressure vessel steel A533B to investigate the effect of biaxial loading on fracture performance at temperatures towards the lower shelf of the ductile-brittle transition. These tests have been conducted using a purpose built test rig in which a cruciform specimen is loaded so that a central region (approximately 500 mm2) experienced uniform (equibiaxial) stressing. These tests are compared to the behavior of wide plates under uniaxial loading. Small-scale three-point-bend tests have also been performed to aid the interpretation of the large-scale test results. This paper describes the experimental method and draws the following conclusions from the test results: 1. Failure conditions toward the lower shelf of toughness for equibiaxial and uniaxial loadings may be safely predicted from full thickness three-point-bend specimens. 2. The stress intensity factor (Kc) at failure would appear to be lower under equibiaxial than under uniaxial conditions. In addition, much greater plasticity (as measured by CTOD and stretch zone width) occurs in the uniaxial case. 3. Under equibiaxial conditions, preloading at + 70°C to loads at K levels which could cause final fracture at -130°C would appear to have no significant effect on the fracture performance at the low temperature.
Evaluation of Elastic-Plastic Surface Flaw Behavior and Related Parameters Using Surface Displacement Measurements
Authors: Lloyd WR , Reuter WG
Published: March 2009

Surface displacement measurements on surface cracked plate specimens loaded in tension were recorded using geometric moiré. An algorithm based on the displacements predicted by HRR fields was developed by the authors and used to evaluate the value of the applied J-integral at the crack border/free surface intersection point at various levels of applied remote stress. The values of J calculated in this manner were found to be in good agreement with predictions by Parks obtained from a nonlinear three-dimensional finite element model (ABAQUS).
Microscopic Aspects of Ductile Tearing Resistance in AISI Type 303 Stainless Steel
Authors: Saxena A , Daly DC , Ernst HA , Banerji K
Published: March 2009

The initiation toughness (JIc) and the resistance to stable crack growth (JR-curve) of AISI Type 303 stainless steel were characterized using side-grooved compact-type specimens. The test material was produced by a hot extrusion process which resulted in long cylindrical MnS inclusions aligned in the longitudinal direction. In addition, several interrupted tests were conducted in which CT specimens were loaded monotonically to different levels of stable crack growth. These specimens were sectioned at mid-thickness for detailed metallography to observe the microscopic aspects of the ductile crack growth process and the evolution of damage ahead of the crack tip. Following is a summary of the results and the conclusions from the study.

Stable crack growth or ductile tearing occurs by nucleation, growth, and coalescence of voids which nucleate at the inclusions. Void growth appears to be most dominant during stable crack growth. At JIc the void closest to the initial crack tip coalesces with the crack. During this period, growth of voids further away from the crack tip also occurs. Thus the increment in J required to continue the crack growth process decreases progressively until a steady-state dJR/da is obtained.

Based on the observations of this study and the void growth model of Rice and Tracey, a simple model relating the microstructural parameters such as inclusion spacing and size to the stable crack growth resistance of the material is proposed. The model is capable of predicting the JR-curve. The predicted JR-curve for the test material agreed with the observed behavior.
Assessment of Influence Function for Elliptical Cracks Subjected to Uniform Tension and to Pure Bending
Authors: Oore M
Published: March 2009

A root mean square (RMS) type stress intensity factor, K, which is defined and used in [1] and [2] for crack growth and fracture calculations, is investigated in this study. Whereas the common K studies use approximate numerical integration of the influence function to analyze various configurations, in the present study the K definition is used analytically to derive accurate K values for various ellipticaljiracks subjected to uniform tensile stress and also to pure bending. The significance of these K results are explored via comparison with the exact classical maximum and minimum stress intensity factors along the front of the corresponding elliptical cracks.
Application of the CEGB Failure Assessment Procedure, R6, to Surface Flaws
Authors: Chell GG
Published: March 2009

The application of the R6 failure assessment procedure to surface flaws requires the definition of a plastic yield load that characterizes the crack tip deformation at both the deepest and surface points on the defect. In this paper the results of finite element computations of the J-integral are used to identify the most appropriate yield loads. This is achieved by assuming that the Option 2 failure assessment diagram (FAD), which is based on a reference stress approximation to J, provides a good approximation to the Option 3 FAD, which is derived from the computed J values. The finite element results for surface flaws in plates and cylinders are used in the investigation. It is demonstrated that global yield loads, which characterize the overall plastic deformation of the cracked structure, produce a better agreement between the R6 procedure, and the finite element solutions, than do local yield loads, which are usually chosen to characterize the plastic deformation at a specific location on the crack front.
Closure Measurements via a Generalized Threshold Concept
Authors: Marci G , Castro DE , Bachmann V
Published: March 2009

Fatigue thresholds have been determined for Inconel 617 and Ti-6Al-4V that are unaffected by any closure phenomenon. These results show that a nonpropagation condition exists between Kop and Kmax of unique amplitude ΔKT which is unaffected by the position between Kop and Kmax. This experimental fact opens up the possibility of measuring the dividing point Kop (fixing the ΔKeff) based on a propagation/nonpropagation criterion. Three such test methods are proposed. Results of these measurements are compared with Kop determinations via load-displacement curves made in parallel on Inconel 617. Comparison of both results show that they contradict each other.

It is concluded that the two different experimental procedures determine and characterize two independent phenomena affecting the fatigue crack growth process differently. Characterizing the two different phenomena by Kop is incorrect.
Load-Point Compliance for the Arc-Bend/Arc-Support Fracture Toughness Specimen
Authors: Baratta FI , Kapp JA , Saunders DS
Published: March 2009

The primary objective of this work is to provide the theoretical computation of load-point compliance for the arc-bend/arc-support specimen and some experimental verification of these predictions. This specimen is a segment of an annular disk loaded in three-point bending with the roller supports positioned at the inside surface.

Load-line compliance was determined principally by utilizing Irwin's equation that relates the compliance rate of change with crack length to the strain energy release rate. The strain energy release rate was determined from the stress intensity solution available in the literature for this sample. Corroboration was also provided by utilizing boundary collocation, boundary integral element (BIE), and finite element (FEM) methods. Representative cases were experimentally tested to confirm theoretical and numerical results. During the tests, it was also found that duplication of idealized support and fixture conditions was extremely important with regard to accurate measurement of load-point compliance.

Two statically equivalent models were used to calculate the load-line compliance using the numerical methods. The first we call Model 1, where the load point is fixed and the roller reactions are applied at the appropriate location. The second we call Model 2, where the load is applied at the load point and the roller reaction points are fixed in the appropriate manner. Although both models are statically equivalent, significantly different load-line compliances are obtained depending upon the model chosen.

Experimental results were also obtained. Specimens were tested with machined slots to simulate a crack and other specimens tested had fatigue cracks. The measured compliances were found to agree with Model 2 results in some cases, with Model 1 in others, and with neither in still others.
Practical Aspects of Evaluating the Chemical Compatibility of Geomembranes for Waste Containment Applications
Authors: White DF , Verschoor KL
Published: March 2009

Chemical compatibility testing (EPA Method 9090) has been applied to many combinations of natural and synthetic leachates and geomembranes. A number of commercial laboratories are currently performing the method, and significant experience has been gained in its application. This paper will describe some practical aspects of chemical compatibility testing which have implications for proper selection of materials for hazardous waste containment.
Accelerated Testing Methods for Evaluating Polyolefin Stability
Authors: Gray RL
Published: March 2009

Most polymeric materials are subject to oxidation; the rate of oxidation depends on the polymer, fabrication methods, and end use conditions. Oxidation of polyolefins can result in discoloration and loss of physical properties such as elongation, impact strength, tensile strength and flexibility. Antioxidants and light stabilizers protect polyolefins against oxidation by controlling molecular weight change and the ensuing loss of physical and mechanical properties.

Careful evaluation of the long-term performance of polyolefins is critical to the successful development of new stabilization systems. While real-time outdoor exposure of materials is desirable, it is usually not practical due to the exposure times required. Consequently, several accelerated aging methods have been developed. This paper will discuss and compare commonly used accelerated test methods.
Determining the Transport Through Geomembranes of Various Permeants in Different Applications
Authors: Haxo HE
Published: March 2009

The widely different uses of geomembranes as barriers to the transport and migration of different gases, vapors, and liquids under different service conditions require a determination of permeability by test methods appropriate to the service. Geomembranes are nonporous and homogeneous materials that permeate gases, vapors, and liquids on a molecular scale by dissolution in the geomembrane and diffusion through the geomembrane. The rate of transmission of a given species, whether as a single permeant or in mixtures, is driven by its chemical potential or concentration gradient. Various methods to assess the permeability of geomembranes to single component permeants, such as individual gases, vapors, and liquids are described and data are presented. In addition, various test methods for the measurement of permeation and transmission through geomembranes of individual species in complex mixtures such as waste liquids are described and data are presented.
Ductile-To-Brittle Transition Time in Polyethylene Geomembrane Sheet
Authors: Halse YH , Lord AE , Koerner RM
Published: March 2009

The susceptibility of polyethylene (PE) geomembranes to stress cracking was evaluated in the laboratory using an accelerated notched constant load testing (NCLT) method. The test specimens were subjected to various stress levels which ranged from 25% to 70% of the yield stress at 50°C. The ductile-to-brittle failure curves of five different geomembranes were obtained by plotting the logarithm of percent yield stress against the logarithm of average failure time. The stress cracking resistance (SCR) is quantified as the value of the ductile-to-brittle transition time. The results show that SCR of these geomembrane sheets vary over a wide range from a minimum of 4 hours to over 600 hours.
The High pH Chemical and Radiation Compatibility of Various Liner Materials
Authors: Whyatt GA , Farnsworth RK
Published: March 2009

A flexible membrane liner has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90°C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault.

The acceptance criteria for judging the compatibility of the liner with radiation should be different than those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates.
Solvent Swell of Polyethylene by Thermomechanical Analysis
Authors: Thomas RW , Cadwallader MW
Published: March 2009

An important property of high density polyethylene (HDPE) for lining waste management facilities is how it behaves when exposed to chemicals. A new method to study this has been developed with the use of a thermomechanical analyzer (TMA). The technique monitors the size of a sample as a function of time while it is exposed to a challenge chemical. The resulting absorption curve can be used to generate the coefficient of diffusivity and the percentage swell at equilibrium. Four different densities of PE were studied by this method. The results showed that the diffusivity, solubility and permeability of a PE resin are dramatically affected by the resin density.
Development of a Short Term Testing Method for Welded Liners
Authors: Schmachtenberg E , Bielefeldt KF
Published: March 2009

One of the critical areas of a sealing made of polymer liners is the seam. The difficult and often changing conditions during welding on the site are the reason for this. Since nondestructive testing methods do not control the adhesion of the junction, destructive testing of welded samples is necessary.With the control of the welding parameters during the welding process, constant quality can be guaranteed. Therefore it is of great interest, to find testing methods which allow to improve the quality of the seam in a short term testing procedure. This way, the parameters for the welding process and seam quality can be optimized on the site.

In a reseach project, sponsored by the German Department of the Environment and performed by the Süddeutsche Kunststoff Zentrum, several tests on welded samples were carried out, related to the different properties. To test the adhesive forces in the seam, peeling tensile tests at elevated temperatures and constant loads allow best distinction. Correlations between time to failure in the long-term peel test and geometry of the seam could be found. For correlations between ageing of the polymer material caused by the welding and internal stress in the seam, no simple test procedure could be found up to this day. The project will be continued.
Assessment of Current Chemical Compatibility Test Methods Used to Evaluate Geotextile, Geonets and Pipe
Authors: Verschoor KL , White DF , Allen SR
Published: March 2009

Chemical compatibility testing of geosynthetics material used in waste management facilities is necessary to assess the compatibility of these materials with the liquid they will contact. EPA Method 9090 only addresses specific test methods to be used for geomembranes. Geosynthetic testing laboratories have adapted this method to test geotextiles, geonets, and pipe. Current test practices for these materials are reviewed. Advantages and disadvantages to specific methods are discussed.
Leachate Compatibility of Polyester Needlepunched Nonwoven Geotextiles
Authors: Sprague CJ
Published: March 2009

The durability of geotextiles — that is, the ability of the geotextile microstructure to resist degradation — is an important criterion for geotextile selection. The durability of a geotextile is influenced by its unique characteristics, such as polymer type, additives used, processing history, bonding mechanism, fiber element geometry, and fabric construction. Therefore, product specific testing is the only dependable approach to characterize the durability of a given geotextile. This paper details chemical and leachate compatibility testing of polyester needlepunched nonwoven geotextiles.
Measuring In-Plane Hydraulic Conductivity of Geotextiles
Authors: Ling HI , Tatsuoka F , Wu JTH
Published: March 2009

An apparatus was developed to measure the in-plane hydraulic conductivity of geotextiles. The apparatus is capable of measuring geotextile transmissivities under specified constant hydraulic heads, subject to simulated stress conditions, and in the confinement of soil. Using the new apparatus, a nonwoven geotextile and a woven-nonwoven composite geotextile were tested to measure their in-plane hydraulic conductivities under various normal stresses. Excellent repeatability of the test results were obtained. Three means of confinement for the geotextile (namely, using rigid blocks, flexible membranes, and soil) were employed for simulation of the in-soil condition. In addition, geotextile specimens retrieved from a field embankment were tested to examine the changes in its transmissivities from those of fresh specimens.
Geotextile Filtration Performance Test
Authors: Montero CM , Overmann LK
Published: March 2009

A rapid test has been developed to observe the actual filtration performance of nonwoven geotextiles with site-specific soils. The test is a variation of the “Slurry Test” developed by Dr. James L. Sherard, and is performed by replacing the granular medium in Sherards' test with a geotextile. Several tests were performed with fine-grained soils and nonwoven geotextiles of different mass per unit area, thickness and apparent opening size (AOS). It was observed that the phenomena that occurred in the geotextile filtration test are similar to described by Sherard during his research. In successful tests, the initial outflow is turbid but clears within a short period of time and a “filter cake” forms at the geotextile-slurry interface. In unsuccessful tests, a large amount of soil passes through the geotextile and/or no “filter cake” forms.
Long-Term Clogging Behavior of Non-Woven Geotextiles with Silty and Gap-Graded Sands
Authors: Bhatia SK , Qureshi S , Kogler RM
Published: March 2009

Non-woven geotextiles are generally used for the protection of synthetic liners in sanitary landfills. In this application the geotextiles perform as a filter and drain for the leachate collection system. Since geotextiles play a major role in landfill design, they should be properly selected to obviate any clogging problems. Filtration criterion for the non-woven geotextiles are still evolving. The existing filter criteria are not applicable for silty and gap-graded soils. In this paper, the results are presented for six different nonwoven geotextiles which are tested with eighteen different gap-graded soils to evaluate long-term filtration behaviors. Microstructure analysis results are provided for a better understanding of the clogging mechanism of non-woven geotextiles.
Biological and Particulate Clogging of Geotextile/Soil Filter Systems
Authors: Rohde JR , Gribb MM
Published: March 2009

Despite the increasing use of geotextiles in leachate collection systems, the long-term filtration performance of these materials has yet to be determined. A laboratory testing program was undertaken to investigate biological and particulate clogging of a typical geotextile. Four permeameters modeling a leachate collection system were subjected to flow of municipal landfill leachate under anaerobic conditions. Poisons were utilized in half of the permeameters to inhibit biological activity, thus allowing comparisons to be made between biologically active and inactive systems. Volumetric flow rates decreased 92 to 97% in all permeameters despite increases in applied head from 6.5 to 35.5 cm. Large head losses were observed in the first several centimeters of soil immediately after the flow of leachate was initiated. Head losses over the geotextiles increased as the study progressed, with the unpoisoned geotextiles showing greater clogging.
Microstructural Analysis of a Polypropylene Geotextile After Long-Term Outdoor Exposure
Authors: Tisinger LG , Peggs ID , Dudzik BE , Winfree JP , Carraher CE
Published: March 2009

An investigation in two phases was conducted to characterize and evaluate the cause(s) of field deterioration of both black and white nonwoven polypropylene geotextiles in a municipal landfill. A preliminary determination was made in the first phase that the observed decay varied between the materials and was the result of damaging thermal effects and mechanical stress. Observational and analytical data supported but did not definitively establish the causal agents. The second test phase was designed to reproduce the failure mode; it involved thermal exposure of restrained (stressed) and unrestrained samples of black 270 g/m2 (8 oz/yd2) geotextile. An unexposed sample was used to obtain control values. After 72 days of exposure, degradation of the specimens was assessed by measurement of physical and mechanical properties and by scanning electron microscope and microstructural analytical techniques.
Examination of PVC in a ‘Top Cap’ Application
Authors: Levin SB , Hammond MD
Published: March 2009

The PVC liner installed over Phase I of the Dyer Boulevard Landfill provides us with an opportunity to examine the material after 5+ years of exposure to landfill gas and other environmental stresses in a top cap application. Test results for samples extracted from the cap are compared to test results obtained at the time of installation, to material properties included within the original material specification, and to material properties from a ‘control’ sample of excess PVC material from this closure project kept in a warehouse since 1983/84.
Development of Guidelines for Testing Pesticide Toxicity to Nontarget Plants for Canada
Authors: Freemark K , MacQuarrie P , Swanson S , Peterson H
Published: March 2009

Guidelines are currently being developed to outline requirements for nontarget plant testing for pesticide registration in Canada. The Saskatchewan Research Council (SRC), under contract to Environment Canada, evaluated international regulatory requirements and test protocols, identified research needs, and recommended guidelines for Canada, by reviewing the scientific literature and databases, and consulting with regulators and scientists involved in phytotoxicity testing. Highlights of the SRC reports and a review by a federal working committee are presented to stimulate additional research, and to solicit critical review from scientists and regulators prior to formal drafting of Canadian regulatory guidelines.
Use of Algae versus Vascular Plants to Test for Chemical Toxicity
Authors: Fletcher JS
Published: March 2009

The credibility of using an algal plant as a surrogate for vascular plants in chemical toxicity testing was evaluated. Data taken from the PHYTOTOX database were used to estimate what proportion of the chemicals reported to influence vascular plants would also influence algae. The relative sensitivity of algae versus vascular plants to common herbicides was also examined. Analysis of the data suggested that approximately 20% of the time an algal screening test for chemical toxicity may not detect chemicals that elicit a response unique to the growth and development of vascular plants. Another conclusion was that no single plant type (algal, monocotyledon, or dicotyledon plant) can always be viewed as the least or most sensitive test system.
Characterization of Xenobiotic Uptake Utilizing an Isolated Root Uptake Test (IRUT) and a Whole Plant Uptake Test (WPUT)
Authors: Krstich MA , Schwarz OJ
Published: March 2009

An isolated root uptake test (IRUT) and a whole plant uptake test (WPUT) were used to characterize the uptake and bioaccumulation of naphthol in two varieties of fescue (Festuca arundinaceae Schreb. var. KY-31 and var. Auburn) and one variety of clover (Trifolium pratense L. var. Redland). Whole plant uptake tests (WPUT) run for 24, 48, and 72 h revealed that the amount of radiolabel translocated to the shoots of both species was directly related to the length of exposure time. 14C-naphthol concentration in the roots of whole plants was directly proportional to naphthol concentration in solution between 0.1 and 0.3 μM. The transpiration stream concentration factor (TSCF) in both varieties of fescue decreased with increasing naphthol concentration in solution. 14C-naphthol elution from the apparent free space (AFS) was very rapid, occurring in less than 1 min. The AFS volume of clover and KY-31 fescue was determined to be approximately 10% of the total root volume. Isolated root tissue, incubated in 10 μM naphthol for 24 h, contained less than 1% of the radiolabel as recoverable parent compound.
A Bioindicator System Assessing Air Quality Within Minnesota
Authors: Kromroy KW , Olson MF , Grigal DF , Teng PS , French DR , Amundson GH
Published: March 2009

The Minnesota Bioindicator Study is a long-term field research project. It has three main objectives: (1) to develop a biological system to indicate the spatial and temporal distribution of air pollutants; (2) to determine the effects of air pollutants on important agronomic and forest species; and (3) to archive biological and environmental data, including samples of soil and plant material for future elemental analyses. Ten field plots were established throughout the state and planted with a variety of commercial and non-commercial plant species. Plants were grown in one or more of three different soil regimes. Plant growth and symptom data were collected during the growing seasons of 1983–1987. Air pollutant and weather data were obtained from local and national agencies. No symptoms of sulfur dioxide injury were confirmed, but symptoms of ozone injury were observed in all five years on milkweed, soybean, and/or potato. Preliminary analyses do not indicate statewide effects of ozone on alfalfa yield. About 2000 samples of soil and plant material are stored, and 1.75 million data points have been accumulated. Data from this study are to provide a baseline for documenting long-term changes in the quality of Minnesota's environment.
The Vicia Leaf Tip Cell-Micronucleus Bioassay and Air Pollution Monitoring
Authors: Guangrong C , Bo J , Ming L , Xingguo W
Published: March 2009

We study the Vicia faba leaf tip cell-micronucleus test (Vicia-LTMT) to expand the monitoring scope of the Vicia plant. The paper reports positive findings in detecting poisonous gas (xylene, hydrogen sulfide) by the utilization of Vicia-LTMT. The in situ monitoring of air pollution in Huangshi, an industrial area, was conducted at four locations, where seedlings were exposed for 4 h. The micronucleus (MCN) frequencies of the V. faba leaf tip cells in each location were obviously higher than the control (F > F0.01, P < 0.01) by statistical analysis. The results show various degrees of pollution in these industrial areas.
Survey of Rocky Mountain Arsenal for Phytotoxic Substances
Authors: Sirois DL
Published: March 2009

For some years, beginning in 1941, military and industrial wastes were disposed of at the Rocky Mountain Arsenal (RMA) located near Denver, Colorado. A comprehensive study of RMA supported by the United States Army was conducted several years ago. Efforts were made to identify suspected toxic substances within the confines of or possibly migrating from RMA. For this study, bioassays were made in the glasshouse on soil samples taken from RMA. The tests were patterned after tests routinely used to identify herbicidal activity. Inhibition of seed germination or retardation of growth and development of seedlings grown in the soils were major criteria for indicating the presence of substances toxic to plants. In addition, observations were made of chlorosis, foliar necrosis, formative effects, and other symptoms indicative of phytotoxicity. Test results showed evidence of toxicity on plants grown in soil samples from Section 36 in the center of RMA. The experimental approach proved appropriate. Influences due to test species, seasonal variation of the greenhouse environment, and data analysis were evaluated.
Protocol for Evaluating Soil Contaminated with Fuel or Herbicide
Authors: Lillie TH , Bartine RW
Published: March 2009

Sorghum and pinto bean plants were used as indicator organisms in a 14-day laboratory test to determine the impact of fuel and herbicide spills in agroecosystems. Plant survival and shoot length (from soil level to tip of highest leaf) were recorded and compared for plants grown in laboratory control soil and soil collected from the accident site. We also used soil from an uncontaminated area near the accident site as a control whenever possible. Chemical analysis was used to verify contaminants.
Use of Thalassia and Its Epiphytes for Toxicity Assessment: Effects of a Drilling Fluid and Tributyltin
Authors: Macauley JM , Clark JR , Pitts AR
Published: March 2009

Concurrent 12-week laboratory and field studies were conducted to determine toxicity of the suspended particulate phase (SPP) of drilling fluid to Thalassia testudinum and its epiphytes. Test systems were treated once per week to achieve nominal concentrations of 100 mg/L SPP. Chlorophyll content of Thalassia leaves and epiphyte biomass and chlorophyll content were monitored during each test. Laboratory exposures were conducted in 7-L, flow-through (7 L/h) microcosms consisting of Plexiglas cylinders containing intact cores of Thalassia from a local seagrass bed. Field exposures were conducted in water-tight Plexiglas chambers (2 by 2 by 1.5 m) placed over test plots in a seagrass bed for 24 h during SPP additions. The chamber base was buried several centimetres into the sediment to minimize water exchange. Drilling fluid exposure had no significant effect on chlorophyll a or b content of Thalassia leaves in laboratory or field tests. Epiphyte biomass was reduced after 6 weeks of intermittent exposure to SPP in laboratory and field tests. After 12 weeks, epiphyte biomass had increased to densities similar to control values.

Tributyltin chloride (TBT-Cl) was tested only in laboratory systems, using weekly treatments for 6 weeks. Nominal test concentrations ranged from 0.2 to 50 μg/L. Leaf protein and rhizome carbohydrate content of Thalassia were employed as effect measures in the TBT-Cl test. Leaf concentrations of chlorophyll a and b were not affected by exposure to TBT-Cl at nominal concentrations ⩽ 50 μg/L. Leaf protein and rhizome carbohydrate concentrations were reduced by exposure to 50 μg/L TBT-Cl. Epiphyte biomass was reduced after exposure to 50 μg/L TBT-Cl for 6 weeks; concentrations ⩽ 20 μg/L had no effect on epiphyte biomass.
A Plant Toxicity Test with the Moss Physcomitrella patens (Hedw.) B.S.G.
Authors: Morgan EL , Wu Y-CA , Young RC
Published: March 2009

A method for detecting toxicity to a representative primary producer was developed and tested using the moss Physcomitrella patens (Hedw.) B.S.G. Cultures of the moss were maintained on solid minimal medium in a growth chamber with a day length of 17 h and a temperature of 23 ± 1°C. Two stages of the moss life cycle (spore and gametophore) were cultured for five weeks in the laboratory while being exposed to various toxic treatments.

Cultures were exposed separately to six different salt solutions (aluminum sulfate, barium chloride, boric acid, cadmium chloride, cobalt chloride, and lead nitrate), a mineralized-acidic leachate, and a coal combustion fly ash leachate. After five weeks' exposure, morphological changes, dry weight, chlorophylls a and b, and total chlorophyll measurements were used as criteria to reflect dose-effect relationships.

Regenerating clones were frequently morphologically aberrant, and no regenerants were observed at higher concentrations of most treatments. Increasing toxicant concentrations generally reduced the dry weight and chlorophyll contents of moss cultures (P ⩽ 0.05). No significant differences in response variables between spore and gametophore cultures were found, and dose-linked changes in fresh weight were similar to those for dry weight.

Cadium chloride and aluminum sulfate treatments had the most negative influence on moss dry weight and chlorophyll content; boric acid and barium chloride concentrations were the least toxic. The fly ash leachate did not appear to be toxic, possibly due to antagonistic chemical interactions in the fly ash/limestone scrubber leachate treatments.
Millet Root Elongation in Toxicological Studies of Heavy Metals: A Mathematical Model
Authors: Wang W , Elseth G
Published: March 2009

Plant seed germination and root elongation, the first phase of plant development, are sensitive to adverse environmental stress. The objectives of this study were (1) to use a millet root elongation method for measuring phytotoxicity of heavy metals and (2) to develop a mathematical model to relate the phytotoxicity of the metals to the root elongation effect and also to provide a basis for linear transformation of the data. The results show that the order of decreasing phytotoxicity of the metals is Cu, Ni, Cd, Cr(VI), Zn, Mn, and Ba. The metal toxicity is on the same order of magnitude in the millet, fish, and duckweed tests.

A mathematical model was developed: P−PMPM =A[M] BK⁢+ [M]K⁢+ [M] where A, B, and K are constants under conditions where metal concentration M is the only experimental variable. PM is the root elongation in the presence of added metal ions and P is that in the control group.

A computer program has been developed to calculate the theoretical values of these metals. These values are in good agreement with experimental values. This model is likely to be applicable to other toxicity tests as well.
The Role of Chlorophyll Fluorescence as a Bioassay for Assessment of Toxicity in Plants
Authors: Miles D
Published: March 2009

The typical green terrestrial plant is well adapted to sensing and reporting significant changes in its environment. This allows native plants growing in natural settings to be used to assess changes that might be toxic to plant or animal tissue. The basis of this bioassay is the chlorophyll molecule, which serves as an intrinsic fluorescent probe of the performance and capacity of photosynthesis. Under normal conditions, 97% of the light energy absorbed by chlorophyll is converted to biochemical forms of energy in photosynthesis. Stress conditions can reduce the rate of photosynthesis, disturb the pigment-protein apparatus, or block the light-driven photosynthetic electron transport in the chloroplast. This results in an increased loss of absorbed light energy of 6 to 10% via chlorophyll fluorescence with a peak in emission at 683 nm at physiological temperatures. The inverse relationship between in vivo chlorophyll fluorescence and photosynthesis has long been known as the Kautsky Effect.

Light-induced chlorophyll fluorescence from dark-adapted leaves can be recorded with portable, sensitive instruments using intact leaves. This nondestructive method essentially monitors the physiological well-being of the plant. Any stress including disease, nutritional stress, water, temperature, radiation, and chemical stress can be quickly and accurately recorded. The overall photosynthetic process can be thought of as a series of sensitive sites connected to the fluorescent photosynthetic reaction center, which respond to a large number of different insults and report these effects as a change in fluorescence. Chlorophyll fluorescence in intact native plants can be used to assess toxicity in the environment or in a laboratory bioassay.
Activation of Promutagens by a Unicellular Green Alga
Authors: Sauser KR , Klaine SJ
Published: March 2009

Classic mutagenicity testing includes mammalian activation of promutagens. A relatively new approach to examining environmental mutagens involves the plant activation of promutagens. A plant system was developed using the aquatic unicellular green alga Selenastrum capricornutum as the activating mechanism. The genetic indicator organism used was the Ames strain TA98 of Salmonella typhimurium. Two treatment groups were examined: alga, TA98, and a test chemical incubated together; and TA98 and a test chemical incubated together without the alga. The test chemicals examined were m-phenylenediamine (MPD), aflatoxin B1, and atrazine. Differences in the number of revertants were compared between the reaction mixtures of the two treatment groups. For MPD and aflatoxin, there was a significant difference between the two treatment groups with the algal treatment group producing a higher number of revertants. There was no effect seen with the atrazine at the concentrations tested or with the TA98 strain. It was shown that the chemically treated alga does not act as an exogenous source of histidine for the TA98. Selenastrum demonstrated a consistent trend of weak activation of the promutagens MPD and aflatoxin B1.