bluuebunny/crossref_metadata_2025 huggingface dataset:
An Aquatic Toxicity Test Using the Moss Physcomitrella Patens (Hedw) B.S.G.
Authors: Morgan EL , Wu Y-CA , Swigert JP
Published: March 2009

A test method was developed for aquatic toxicity using an autotroph, the moss Physcomitrella patens (Hedw.) B.S.G. Regenerating moss clonal colonies were treated with various toxicants and incubated in liquid minimal medium in a growth chamber. Colonies were subjected to a test matrix of six different salt solutions (for example, aluminum sulfate, barium chloride, boric acid, cadmium chloride, cobalt chloride, and lead nitrate), an acidic leachate, and a coal combustion-limestone scrubber fly-ash leachate. After five weeks' exposure to various treatment concentrations of each substance, colony biomass (wet-dry weight) and chlorophyll (a, b, total) contents were used as criteria to judge concentration-effect relationships.

No regenerates were observed at the higher treatment levels of most toxicants. Generally, increased treatment concentrations reduced moss dry weight and chlorophyll contents (P ⩻0.05). Morphological changes were less distinct than those of cultures treated in previous studies on solid medium. Cadmium chloride, boric acid, and lead nitrate had a pronounced detrimental effect on moss dry weight and chlorophyll; fly ash and Anakeesta leachates and cobalt chloride were the least toxic at the concentrations tested according to the criteria observed. In summary, liquid-medium cultures have specific application to aquatic phytotox-icity testing because: (1) dry weight and chlorophyll-content measurements provide quantifiable response criteria for judging toxic effects; (2) colonies may be transferred to solid phase media at any time in the test period to promote vegetative stages of gametophores; (3) test systems are responsive to toxicants at small exposure volumes; (4) populations are clonal, being homogenous genetically and can be tested under transboundary states on liquid and/or solid medium; and (5) they can provide useful information on an important component of ecological communities at costs similar to those for other short-term tests.
Managing Ecological Risks of Contaminated Sediment
Authors: Peddicord RK
Published: March 2009

Much effort has gone into determining the extent of contamination of sediments. However, inadequate attention has been devoted to the implications of classifying a sediment as contaminated. Because sediments are usually addressed under water-oriented regulations, the typical response is to remove contaminated sediments from the waterway. This may or may not be appropriate. In water, most sediments are anoxic, reduced, and near neutral in pH; the resource at risk is the aquatic community. If a sediment is removed from the water, it will dry over time, oxidize, and often decline in pH; the resources at risk include ground water, air, and terrestrial communities. Inadequate consideration of physicochemical conditions and resources at risk associated with various management options can lead to relocating and exacerbating, rather than solving, contaminated sediment problems. Attention must not focus on “might this sediment be a problem in the waterway?” but rather “if this sediment warrants special attention, what is the most appropriate environmental management option?”
A Review of the Current Status of Marine Algal Toxicity Testing in the United States
Authors: Thursby GB , Anderson BS , Walsh GE , Steele RL
Published: March 2009

Algal toxicity testing is not new, but only within the past few years have data from such testing been used to help set standards for allowable contamination. Early toxicity testing with marine algae used a few planktonic species with inhibition of growth as the primary endpoint. Results obtained from these algal tests established a reputation for insen-sitivity to toxicants relative to animals. Work with vegetative growth of marine seaweeds from intertidal areas also led to conclusions of insensitivity to toxicants. Based on this reputation, marine algae as a group have been considered nonessential for assessing effects of pollutants on the marine environment. Within the past five years, tests with different species of microalgae and reproductive tests with marine macroalgae have come into wider use. These new species and test method endpoints have shown that plants can be more sensitive to toxicants than some of the most sensitive marine animals. It has been proposed recently that the saltwater “Criterion Continuous Concentration” for water quality criteria documents for thallium and acenaphthene be set with reproductive data from the kelp, Laminaria saccharina; which was the most chronically sensitive species tested for both chemicals. Plant tests also are now being required for some National Pollutant Discharge Elimination System permits for the marine environment.
Quality Control in Aquatic Toxicity Testing Programs: Evaluation of Copper and Hexavalent Chromium As Reference Toxicants
Authors: Jop KM , Askew AM , Texeira DJ , MacGregor J
Published: March 2009

Increased awareness of the value of effluent toxicity test data has stimulated regulatory agencies to develop and implement quality assurance (QA) programs for laboratories performing effluent toxicity tests. As part of a QA program, a standard reference toxicant program should be conducted to verify the health and acceptability of a particular population of test organisms. The recently issued EPA manual for the evaluation of laboratories performing aquatic testing, a pilot study in 1990 to evaluate performance of aquatic toxicology laboratories in New Jersey and North Carolina, and the first study (DMR-QA Study 11) involving laboratories from all states providing data for the National Pollutant Discharge Elimination System (NPDES) program represent examples of proposed practices that specify quality-control parameters to ensure the acceptability of biological data used in the permitting process.

Two reference toxicants, hexavalent chromium and copper, were tested extensively over a two year period in our laboratory. The mean 48-h LC50 for D. pulex was 188 μg Cr+6/L and 3 μg Cu/L, while the mean 96-hour LC50 for fathead minnows was 83 mg Cr+6/L and 180 μg Cu/L. The coefficient of variation (CV) of LCW values for daphnids were similar for both compounds. However, the CV for fathead minnows test results with copper was approximately three times greater than that for hexavalent chromium.

Comparable to multipoint calibration curves used to define the accuracy of a chemical method, results of toxicity tests conducted on a regular basis using reference toxicants can be used as criteria for accuracy and precision of biological effects studies. Because performance standards for testing laboratories are based on the results from reference tests, this study also provided an opportunity to evaluate current EPA criteria for acceptance. For this evaluation the results of 88 toxicity tests were selected (44 tests with chromium and 44 tests with copper using D. pulex). In our opinion, the results of this study indicated that both biological performance and the results from reference tests are equally important for the evaluation of the health of test organisms.
Elements of Automated Mechanical Testing
Authors: Ruth EA
Published: March 2009

For over 100 years, the words “automatic” and “automated” have been used to describe equipment that tests the mechanical properties of materials. This paper attempts to categorize the various levels of automation used in the past, present, and future. It focuses on the building blocks of automation in use, how to decide what level of automation is correct for an application, and how and what is necessary to integrate the entire system into your process.

This work is based on personal experience with several systems installed in different laboratories. The case cited is the automation of tensile tests in a production test laboratory of an aluminum manufacturer; however, much of the information can be universally applied to other types of tests.

This paper is intended as a primer for those interested or involved in increasing the level of automation in their laboratory.
Automated Data Acquisition and Analysis in a Mechanical Test Lab
Authors: Carter DH , Gibbs WS
Published: March 2009

Computers and enhanced control technology have made it possible to perform more sophisticated mechanical tests than ever before, as well as to allow routine tests to be run and analyzed with much greater efficiency. Automated data acquisition, storage, and analysis have become key ingredients in a mechanical test facility, especially in one which uses a wide variety of test equipment and techniques. This paper will discuss one such mechanical test facility where many different types of mechanical tests are performed using automated data acquisition, centralized data storage, and finally a complex system of automated data analysis. Various systems of data acquisition will be discussed, including those used on servohydraulic and screw-driven systems, as well as those used for higher-rate, formability, and creep tests. Methods for networking equipment used in such a facility will be described. Networking is an important criterion for establishing a centralized data base, and for eventually building a system of automated data analysis.
Event Criteria to Determine Bandwidth and Data Rate in Tensile Testing
Authors: Nicolson AM
Published: March 2009

Methods are presented to estimate the errors in estimating peak and slope values in tensile tests when there are limitations due to the electrical bandwidth of the measuring system and the finite data rate of the digital data acquisition system. Various “events” are defined that can occur along the measured stress-strain characteristic. By convolving with the impulse response of a typical low-pass filter, the effects on these waveform shapes is measured, and graphs are shown which relate the error in estimating the peak value or slope as a function of the bandwidth for a known “event” duration. It is shown that for most simple events a bandwidth of 3/(event-duration) is adequate for peak and slope measurements. For data rates it is shown that a rate of about 30 times minimum bandwidth is necessary for errors less than 1% in peak estimates. A simple method of estimating the actual system bandwidth is demonstrated.
Keynote Speech: A Brief Overview of Plant Toxicity Testing
Authors: Fletcher J
Published: March 2009

In 1962 Rachel Carson's book Silent Spring challenged the world to reevaluate the use and disposal of manmade chemicals. The initial reaction to this classic book was outrage by industry, bewilderment from government, and deep concern on the part of the general public. In the intervening years, attitudes of outrage and bewilderment have disappeared and a growing concern for protecting the environment has emerged among all factions of our society. Accompanying this concern has been an ever increasing trend towards cooperation and responsible action by involved parties. Fundamental to this trend is an awareness of potential hazard posed by manmade chemicals to the environment and agreement on measures which must be taken to avert deterioration of the environment.

Laboratory testing of new chemicals on selected biota has become the primary means for evaluating the potential threat of chemicals to the environment. Although the amount of plant testing has been minimal in the past, it is almost certain that more plant testing will be conducted in the future in an effort to curtail and avoid the decline of plant life in threatened habitats. Thus, it is very timely to examine plant tests in current use in an effort to ascertain if they are economically and scientifically sound and whether or not the laboratory data from these tests are being interpreted accurately for the purpose of environmental protection.
The Use of Soil-Based Plant Tests Based on the OECD Guidelines
Authors: Windeatt AJ , Tapp JF , Stanley RD
Published: March 2009

The European Community (EC) has been developing a plant bioassay within the Organization for Economic Cooperation and Development (OECD), Terrestrial Plants, Growth Test guidelines. The aim has been to obtain a relatively simple, reproducible test that is both flexible and economically viable. Over the past ten years, European government and contract laboratories, including the ICI Brixham Laboratory, have examined the suitability of a range of test species and pot sizes for use in plant tests. Other parameters assessed include the use of pregerminated seeds and the value of randomized experimental design. During this period, these establishments have taken part in two Ring Tests (interlaboratory comparative trials), and this has resulted in several refinements to the test. ICI Brixham Laboratory has adopted the basic guideline of this plant test and has used it, with slight modification, to assess the effect of a range of organic and inorganic chemicals on emergence and early plant growth of a number of plant species. The method is also suitable for adaption to assess the effect of volatile chemicals and of soils amended with sludges from treatment processes on plant growth.
Higher Plants (Common Duckweed, Lettuce, and Rice) for Effluent Toxicity Assessment
Authors: Wang W
Published: March 2009

The objective of this study was to evaluate effluent toxicity using phytotoxicity tests. Samples including receiving water, treated effluent, and pretreated industrial wastewaters were collected from three Illinoisian sanitary districts. These samples were tested as is, using duckweed, lettuce, and rice. The treated effluents from the three sources were not toxic in all tests. A pretreated industrial sample from a metal processing plant showed 98% inhibitory effect on duckweed. The same sample was not toxic to lettuce and rice germination. A sample from a transportation industry was toxic using duckweed, lettuce, and rice tests, having inhibitory effects of 45, 13, and 39%, in that order. A sample from a dairy plant was extremely toxic. The sample as received caused inhibitory effects of 100, 87, and 100%, in the same order of three species. The IC50 value and 95% confidence limit for this sample was 50% and 47 to 53% effluent concentration, respectively, using the duckweed toxicity test method.
Testing for Pesticide Toxicity to Aquatic Plants: Recommendations for Test Species
Authors: Swanson SM , Rickard CP , Freemark KE , MacQuarrie P
Published: March 2009

A literature review of pesticide toxicity to aquatic plants was conducted in order to arrive at a set of species for use in preregistration testing. Criteria used in the selection process were: (1) existing database; (2) interspecies variability in response to pesticides; (3) availability of well-characterized plant cultures; and (4) ease of culture. Freshwater and marine algae and freshwater and estuarine macrophytes were included in the study.

Results showed that the three practical criteria [1,3,4] all resulted in the selection of unicellular green algae (Chlorophyceae) for the freshwater algae tests. However, variability among freshwater species and classes was so great and so unpredictable that it became obvious that a species battery approach was required. The battery should consist of representatives of each of the major algal classes. Research into culture methods and alternative endpoints is required before species other than unicellular green algae can be routinely incorporated into species battery tests.

The studies in the marine algal database had much more consistent methodology; therefore, it was possible to include relative sensitivity and variability as well as practical considerations in the selection of marine tests species. The golden-brown algae (Chrysophyceae) were generally the most sensitive. However, because variability in response was still high, we recommend a species battery for marine algae as well. Four species of golden brown alga, two diatoms (Bacillariophyceae) and two green algae, were chosen based on the four criteria.

Macrophytes should be part of preregistration testing because they can be more sensitive than algae and because of their ecological importance. The database showed a great variety of test methods and very few laboratory methods. No species emerged as the most consistently sensitive among either freshwater or estuarine macrophytes. Lemna gibba and Lemna minor are fast growing, easy to culture, and available commercially; they are logical test species for effects of pesticide drift and surface films. However, they are not always very sensitive. Rooted macrophytes belong in a comprehensive test program; however, test methods have to be developed.

One criterion not included in this study was ecological importance. We recommend that ecological importance become part of any selection process in order to facilitate extrapolation to the field during hazard assessments.
Toxicity Testing Using a Chemostat-Grown Green Alga, Selenastrum Capricornutum
Authors: Peterson HG
Published: March 2009

Regulatory toxicity testing with algae commonly use 72- or 96-h inhibition of growth by the green algae Selenastrum, Chlorella, or Scenedesmus. The long incubation period is sufficient for the algae to change the composition of the test medium. Organism-induced changes include the release of organics and the uptake of nutrients with accompanying pH changes. Both the released organics and the variable pH can change the chemical speciation of the toxicants; this may alter their toxicity. In addition, the competitive interactions between hydrogen ions and toxicants can affect toxicity as the pH varies. It is shown here that cadmium (Cd) toxicity to Selenastrum capricornutum increases by up to eight times for every unit of pH increase. Copper (Cu) with its different speciation pattern does not vary as much as Cd, and the pattern is different. Because the toxicity of the two metals vary differently with pH, Cd is 500 times less toxic than Cu at pH 6, but Cd is twice as toxic as Cu at pH 10.

The present regulatory protocols call for nutrient-sufficient conditions, but algae are likely to be limited by either nitrogen (N) or phosphorus (P) in nature. Here, Selenastrum has been grown in chemostats with both N and P approaching limiting levels. Inhibition of N and P uptake, rather than growth, has been used to assess toxicity in short-term experiments. The advantage of chemostat, rather than batch cultivation (as used in present regulatory tests), is the ability to produce algae of known and well-defined physiological states.
The Effect of Dissolved H2S and CO2 on Short-Term Photosynthesis of Skeletonema Costatum, a Marine Diatom
Authors: Breteler RJ , Buhl RL , Maki AW
Published: March 2009

The planktonic diatom Skeletonema costatum was exposed during 4-h periods to dissolved forms of H2S and CO2. The experimental design permitted evaluation of the acute toxicity of these gases by measuring the reduction in photosynthesis using the 14C assimilation technique. Carbon dioxide gas, measured with a CO2-specific electrode, demonstrated a EC50 value of 0.69-mM molecular CO2. The inhibition in algal photosynthesis was largely attributed to the decrease in pH with increasing exposure concentrations (from pH 8.45 to 5.73). Hydrogen sulfide, measured colorimetrically, showed no adverse effects up to 24-μM total sulfide corresponding with 1.2-μM molecular H2S. The calculated EC50 value was 3.1-μM H2S. The toxicity tests yielded results useful for the assessment of potential harmful effects to marine diatoms of discharge of these gases into ocean waters by off-shore natural gas production platforms.
A Seedling Chlorophyll Fluorescence Toxicity Assay
Authors: Judy BM , Lower WR , Ireland FA , Krause GF
Published: March 2009

Changes in chlorophyll fluorescence yield are related to changes in the photosynthetic efficiency of plants. Under normal conditions, approximately 97% of the light energy absorbed by chlorophyll is converted to oxidation and reduction potential to drive electron transport in photosynthesis. Stress conditions such as those caused by toxic chemicals can reduce the efficiency of photosynthesis by disturbing the pigment protein apparatus or blocking the electron transport system in the chloroplast. The 6 to 10% loss of absorbed light energy due to stress conditions appears as chlorophyll fluorescence. A chlorophyll fluorescence assay can provide a simple, rapid method for measuring the effect of physical and chemical stress on the photosynthetic efficiency of plants. In this study, seedlings of soybean (Glycine max L. Merr.) and barley (Hordeum vulgare L.) were analyzed by chlorophyll fluorescence induction following treatment with three herbicides dissolved in water at three concentrations. The eluate of soil collected from a hazardous landfill was also tested. Several endpoints were measured; initial fluorescence (F0), variable fluorescence (Fv), maximum fluorescence (Fm), Fv/Fm ratio, and electron pool (EP). This study indicated that the decline of photosynthetic efficiency of plants exposed to toxic chemicals in water or soil eluate can be measured by the chlorophyll fluorescence assay method.
Detecting Ambient Cadmium Toxicity in an Ecosystem
Authors: Stewart-Pinkham SM
Published: March 2009

The threshold for a toxic effect from cadmium is close to its background levels. In experimental studies, chronic low-dose exposure does not necessarily increase body burden and causes effects associated with other stressors; therefore, low-dose effects from environmental sources are hard to establish using traditional approaches. The effects of ambient cadmium have increased with the precipitous drop in lead in the atmosphere. They are manifested by increased stress responses. In a community exposed to cadmium fumes from waste incineration, one can infer cadmium effects in such observed environmental stresses as increased seeding in trees, tree injuries, and learning and behavioral problems in children.

Biochemical effects of free cadmium, rather than the levels of cadmium burden or accumulation, need to be assessed in multiple biological systems, especially trees and humans. Environmentally bioavailable cadmium can be detected more accurately by assaying multiple metals in hair, leaves, lichens, and house dust. The hypothesis that cadmium is released with stress and/or mediates the stress response should be directly tested through carefully designed scientific studies.
A Comparative Study of the Bioconcentration and Toxicity of Chlorinated Hydrocarbons in Aquatic Macrophytes and Fish
Authors: Gobas FAPC , Lovett-Doust L , Haffner GD
Published: March 2009

This study reports the uptake and elimination kinetics, the bioconcentration, and the acute toxicity of a series of chlorinated benzenes and biphenyls in a submerged aquatic macrophyte (Myriophyllum spicatum) and in a fish (Poecilia reticulata) species. The objective of this study is to investigate the relationship between the acute lethality in fish and in aquatic plants. The study shows linear relationships between the plant-water and fish-water bioconcentration factors and the 1-octanol-water partition coefficient, indicating that plant-water and fish-water exchange are largely controlled by the chemical's tendency to partition between the lipids of the plants or fish and the water. The toxicokinetics in both the plants and the fish involve “passive” transport phenomena, which can be described by a lipid-water kinetic model. Toxicity data demonstrate that the acute lethality of chlorobenzene and chlorobiphenyl congeners in fish is associated with an internal concentration in the fish of approximately 6330 μmol/L. Based on the similarity of the lethal internal concentration among the chlorobenzene congeners and between various aquatic organisms, it is hypothesized that the acute lethal toxicity of chlorobenzenes in plants and fish are similar, which would provide a basis for the extrapolation of toxicity data between fish and aquatic plants.
Characterization of Eight Soil Types Using the Selenastrum Capricornutum Bioassay
Authors: Ireland FA , Judy BM , Lower WR , Thomas MW , Krause GF , Asfaw A , Sutton WW
Published: March 2009

A recently developed bioassay protocol was used to characterize seven different soil types and Promix BX. The green alga Selenastrum capricornutum was used as the test organism. A ruggedness test which altered seven variables was conducted to identify procedural stipulations that should be carefully controlled in the Selenastrum capricornutum bioassay. Stimulatory or inhibitory effects as measured by population growth were compared to a control using two different nutritional methods termed proportional amendment (PA) and complete amendment (CA). Population growth, calculated effect (CE) values, and EC50 values are given for each soil. A wide range of effects were documented indicating a substantial difference among soils with respect to their ability to stimulate or inhibit algal population growth.
The Influence of Test Length and Bacteria on the Results of Algal Bioassays with Monophenolic Acids
Authors: Larson LJ
Published: March 2009

Static bioassays lasting 11 to 16 days were conducted on Chlorella pyrenoidosa using vanillic acid, syringic acid, and 4-hydroxybenzoic acid. Vanillic and 4-hydroxybenzoic acid were initially inhibitory, then after 3 to 5 days became stimulatory compared to control. Bioassays with syringic acid were all stimulatory except higher concentrations, which resulted in 100% mortality. Bacteria-free cultures of C. pyrenoidosa were stimulated by vanillic acid at low concentration and inhibited at higher levels with no shift in response observed. It was concluded that degradation of test material was responsible for the shift from inhibition to stimulation. This work concludes that the length of tests, as well as whether or not careful monitoring for bacterial contamination was conducted, can have a significant impact on bioassay results.
Tissue Culture as a Method for Evaluating the Biotransformation of Xenobiotics by Plants
Authors: Wickliff C , Fletcher JS
Published: March 2009

Suspension cultures of Rosa cultivar (cv.) Paul's Scarlet were used as a model system to examine the metabolism of 1,3-dinitrobenzene (DNB), an industrial waste compound. In a 3-day period, 90% of the DNB supplied (96 nmol) was metabolized by approximately 12 g (fresh weight) of cells. The primary end product of DNB metabolism partitioned into the insoluble residue fraction of the extracted cells. This study demonstrates the usefulness of plant tissue cultures in evaluating the chemical influence of plants on xenobiotics.
Response of Sago Pondweed, a Submerged Aquatic Macrophyte, to Herbicides in Three Laboratory Culture Systems
Authors: Fleming WJ , Ailstock MS , Momot JJ , Norman CM
Published: March 2009

The phytotoxicity of atrazine, paraquat, glyphosate, and alachlor to sago pond-weed (Potamogeton pectinatus), a submerged aquatic macrophyte, was tested under three types of laboratory culture conditions. In each case, tests were conducted in static systems, the test period was four weeks, and herbicide exposure was chronic, resulting from a single addition of herbicide to the test vessels at the beginning of the test period. The three sets of test conditions employed were: (1) axenic cultures in 125-mL flasks containing a nutrient media and sucrose; (2) a microcosm system employing 18.9-L buckets containing a sand, shell, and peat substrate; and (3) an algae-free system employing 0.95-L jars containing reconstituted freshwater and a nutrient agar substrate. The primary variable measured was biomass production.

Plants grew well in all three test systems, with biomass of untreated plants increasing by a factor of about 5 to 6.5 during the four-week test period. Biomass production in response to herbicide exposure differed significantly among culture systems, which demonstrates the need for a standardized testing protocol for evaluating the effects of toxics on submerged aquatic plants.
X-Ray Microanalysis and Ultrastructure of Lichens from Polluted and Unpolluted Areas
Authors: Favali MA , Corradi MG , Fossati F
Published: March 2009

The thalli of 24 lichen species, collected from unpolluted and polluted suburban areas, were studied by light and electron microscopy in order to detect their morphological and physiological alterations due to air pollution. The effects on photosynthesis were determined by measuring the chlorophyll content of the algae using the autofluorescence test and by the ultrastructural observations of the thylakoid system. The element distribution in the thalli was analyzed by semiquantitative X-ray microanalysis applied to a scanning electron microscope. From our results, it seems that air pollution causes a remarkable drop in chlorophyll content as recorded by measuring the algal autofluorescence and appreciable alterations of the photosynthetic apparatus such as the swelling of the thylakoids observed by electron microscopy. Moreover, X-ray microanalysis shows that the elements always detected in significant amounts are: aluminium (A1), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and calcium (Ca). The element concentration varies in the different portions of the thalli: magnesium (Mg) is located mainly in the algal layers and A1 in the reproductive structures (apothecia) and in the cephalodia, where cyanobacteria are present. The amount of Mg and iron (Fe) is lower in the thalli of Cladonia from unpolluted areas than in those from polluted areas; Cladonia furcata and Dermatocarpon miniatum have a high Si content; Cladonia has also the highest amount of heavy metals and S. Among the techniques used in our research, electron microscopy is the most sensitive one for the documentation of cellular damages; X-ray microanalysis is indispensable to detect heavy metals, but the autofluorescence test seems to be the most useful for a rapid control of the effect of the air pollution on lichen morphology and physiology. Lecanora dispersa, Lecanora hagenii, Physcia adscendens, and Xanthoria parietina are the more tolerant lichens studied.
32P-Postlabeling for DNA Adduct Determination in Plants
Authors: Lower WR , Ireland FA , Judy BM
Published: March 2009

Barley (Hordeum vulgare L.) and Australian saltbush (Atriplex semibaccata)plants and deoxyribonucleic acid (DNA) isolated from barley were exposed to the known carcinogen/mutagen, N-methyl-N-nitrosourea (MNU). DNA was isolated, digested to a mixture of deoxyribonucleoside 5'-monophosphates, postlabeled with [γ-32P] ATP, and separated on polyethyleneimine (PEI)-cellulose thin layer chromatography plates. Autoradiograms of the chromatograms showed the presence of normal DNA constituents as well as additional spots not present on autoradiograms of untreated DNA. These data suggest that DNA adducts are formed in growing plants and in plant DNA exposed to a carcinogen. In addition, a discussion of the 32P-postlabeling procedure and similarities and differences encountered using plants and plant DNA are addressed.
Application of a Plant Test System in the Identification of Potential Genetic Hazards at Chemical Waste Sites
Authors: Gill BS , Sandhu SS , Backer LC , Casto BC
Published: March 2009

In situ evaluations of biological effects of chemicals from industrial waste sites provide an assessment of potential health hazards to humans under the complexities of natural environment. For such studies, plants, being cost effective and suitable for multimedia exposure, are ideal for preliminary investigations for hazard identification. Several native plant species have been used as biomonitors for providing an integrated response to the bioavailability of chemical toxicants in the real-world environment.

We have utilized the Tradescantia micronucleus (Trad-MCN) assay for evaluating genetic hazards at a chemical waste site contaminated with agricultural insecticides scheduled for cleanup under the Superfund program. The chemical analysis of soil samples from the site indicates presence of lindane, beta BHC, and heptachlor in the subsurface samples. Tradescantia plants were planted at five locations to evaluate the mutagenic effects of the total environment, i.e., soil, water, and air. In addition, stem cuttings were also placed at these locations to sample the genetic impact of vapor phase organics in the atmosphere. Surface and subsurface samples were obtained from these locations for chemical and biological analysis in the laboratory. Concurrent laboratory and field controls were maintained in Durham, NC.

Results of Tradescantia exposures at the site showed significantly higher frequencies of micronuclei from contaminated plots before remediation, but no genetic activity was detected after the remedial action. Plants exposed to soil samples in the laboratory yielded nonsignificant results except for one subsurface sample before remediation and two surface samples after remediation. From comparison of plants exposed in the laboratory and under natural conditions, we concluded that genetically effective levels of volatile organics were present at the site before remediation. This study demonstrates the utility of simple bioassays for detecting environmental hazards at chemical waste sites.
A Short-Term Bioassay for Whole Plant Toxicity
Authors: Pfleeger T , Mc Farlane C , Sherman R , Volk G
Published: March 2009

A five-day, whole plant toxicity test was developed and evaluated. The 18 chemicals tested were primarily substituted benzenes and phenols, although representative herbicides, surfactants, and other industrial chemicals were also tested. The test yields information on root and shoot growth as a function of toxic chemical concentration in the root environment and can also be used to determine the effect on transpiration. The measurement found to be the most sensitive indicator of toxicity was total plant growth. EC50 (effective concentration that reduced growth 50%) values were estimated for each compound using regression analysis. This simple bioassay gives a quick response to an acute exposure and can be used to screen chemicals at various concentrations. The beginning of a unique database comparing species, concentrations, and chemical toxicity are presented, and the results are discussed in relation to other phytotoxicity data.
A Comparison of Potentiodynamic Polarization Tests with Wet-Dry Mixed Salt-Spray Testing of Aluminum-Magnesium-Silicon Alloy
Authors: Baker SV , Lyon SB , Thompson GE , Wood GC , Lewis KG
Published: March 2009

Heat-treatable Al-Mg-Si alloy, in the form of all aluminum alloy conductor, (AAAC), has recently been introduced for overhead electrical supply in the United Kingdom. The material supplied to the industry in the United Kingdom may have differing corrosion resistance as a result of the different thermal histories of the alloy during manufacture. This paper presents data on the corrosion resistance of the aluminum alloy in a salt-spray test and compares this with the results of a potentiodynamic pitting test which has been proposed as a rapid assessment method for quality control of AAAC. Four batches of AAAC with differing thermal histories, were studied. The parameters measured include weight loss, loss in mechanical properties, and pitting data. The results indicated that the four alloys exhibit different corrosion characteristics in salt-spray accelerated corrosion tests. However, the potentiodynamic pitting test data failed to consistently rank the alloys in a discrete order. The data produced from both of the testing techniques are reviewed and contrasted. The results suggest that potentiodynamic tests are unable to characterize the atmospheric corrosion resistance of aluminum alloys. Thus, the adoption of such a test, as a quick screening technique, is not justifiable.
Time-Lapse Video Techniques in the Corrosion Testing of Aluminum Alloys
Authors: Newton CJ , Holroyd NJH
Published: March 2009

This paper describes the use of time-lapse video techniques for in situ observation during controlled and free corrosion of high-strength Al-Zn-Mg-Cu alloys 7075 and 7150 and two Al-Zn binary alloys. Direct observation of corroding 7075 in various tempers shows that, as a precursor to stable pit formation, a deformable gelatinous layer of corrosion product develops. Gas is evolved at the metal/hydrated oxide interface, which distorts the gel layer at potentials below those expected for pitting. During stress corrosion cracking of 7150 T6, time-lapse video images confirm that initial drying after total immersion of 0.6M NaCl solution leads to an acceleration in the apparent rate of crack growth from 5 × 10-7 m/s to 9 × 10-6 m/s. This rate is sustained for only a few minutes but could help explain the aggressive nature of alternate immersion testing.
Passivation in Rare Earth Metal Chlorides—A New Conversion Coating Process for Aluminum Alloys
Authors: Shih H , Mansfeld F
Published: March 2009

Investigations in this laboratory have shown that immersion of Al 6061-T6 and Al 7075-T6 in 1000 ppm CeCl3 produces very corrosion-resistant surfaces. For Al 6061-T6 that had been treated in 1000 ppm CeCl3 for one week, pitting did not occur in 0.5N NaCl for two months. Similar results have been obtained for immersion in NdCl3 and PrCl3, but not in LaCl3 and YCl3. The effects of the concentration of the passivation solutions, the length of exposure time and type of surface preparation have been investigated in more detail using electrochemical impedance spectroscopy (EIS) and d-c techniques. EIS data and d-c polarization curves have been determined during the passivation process and during subsequent exposure to NaCl. In addition, surface analysis has been performed using scanning electron microscopy with energy-dispersive X-ray analysis (SEM/EDAX) and scanning Auger electron spectroscopy (AES). More recent efforts have concentrated on shortening the passivation time. Comparisons with the corrosion behavior of chromate conversion coated aluminum alloys suggest that passivation in rare earth metal chlorides can produce surface films with a corrosion resistance similar to that provided by chromate conversion coatings.
A History of ASTM Accomplishments in Low Temperature Engine Oil Rheology: 1966–1991
Authors: Shaub H
Published: March 2009

A great deal of effort has been expended and many accomplishments realized over the past 25 years in ASTM in the area of low temperature engine oil rheology. One major topic of research and development has been that of low temperature engine oil pumpability. This area has gained at least equal prominence and importance to low temperature (SAE “W” grade) engine oil requirements in SAE J 300, as engine cranking. In addition, a worldwide roundrobin on the Cold Cranking Simulator (CCS) at multiple use temperature was recently completed. This round robin provided a useful precision statement for the Multi-temperature CCS Method in SAE J 300 for establishing meaningful cranking limits for “W” graded oils. This paper will trace the history of these pertinent developments and their timely importance to the automotive industry.
Pumping Viscosity by Mini-Rotary Viscometer: Critical Aspects
Authors: Henderson KO
Published: March 2009

The current ASTM Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low Temperature (D4684-89) was designed to cool an engine oil at a rate that will maximize its tendency to form a flow limiting structure. The cooling program development work with the Pumpability Reference Oils (PRO) demonstrated that temperature control and cooling rate could greatly effect the observed viscosity of the test oil. By utilizing this method, all oils with known field problems are identified by exhibition of a yield stress greater than 35 Pa, and/or excessive viscosity at the appropriate test temperature. During the evaluation of cooling rates, it was found that small differences in test temperature resulted in large differences in observed viscosity of temperature sensitive engine oils. This paper shows the importance of closely monitoring and controlling the cooling rate as well as the final test temperature. Inaccuracy of temperature measurement was the largest contributor to measurement error in determining pumping viscosity.
Passenger Car and Heavy Truck Cold Cranking Studies - Effects of Oil Viscosity and Vehicle Type
Authors: Alexander AG , MacAlpine GA , May CJ , Smith CR
Published: March 2009

In the 1960's and 1970's, engine cold cranking studies on reference oils served as a basis for the development of a standardized laboratory test which measured an oil's viscosity under the appropriate temperature and shear rate conditions (the Cold Cranking Simulator or CCS). However, when the original CCS method (Apparent Viscosity of Engine Oils at Low Temperature Using the Cold-Cranking Simulator, D 2602) was modified to reflect a change from single temperature determinations (-18°C) to a multi-temperature method, concerns regarding test precision and the response of viscoelastic oils prevented the revision of the method to an ASTM standard. The recent development of modified CCS procedures to address these concerns has been somewhat hindered by the lack of available reference oils with supporting engine cranking data. To address this need, Esso Petroleum Canada initiated a limited study of engine cold cranking on four test oils, in 1987. Five different late model passenger cars equipped with 4- and 6-cylinder gasoline engines were subjected to repeated cold starts at temperatures between -15°C and -25°C in an All-Weather Chassis Dynamometer facility. The vehicle cranking results and samples of the test oils were forwarded to the CCS task force in 1987. More recently, Esso Petroleum Canada has undertaken a detailed cold start/pumpability evaluation of multigrade engine oils in three different heavy duty trucks. Cold cranking data from these diesel engines, in addition to the previous gasoline engine studies are discussed with respect to oil viscosity, operating temperature and vehicle effects.
Engine Oil Viscosity Classification Low-Temperature Requirements - Current Status and Future Needs
Authors: Spearot JA
Published: March 2009

The evolution of low-temperature viscosity requirements in the Engine Oil Viscosity Classification, SAE J300, began in 1923 with the introduction of simple limits on the pour point of selected viscosity grades. Since then, low-temperature requirements have evolved into a complex specification system that includes a separate designation (i.e., the “W-grades”), laboratory “cranking” and “pumping” simulators, and complex cooling cycles to which an oil must be subjected prior to measurement. These requirements have been incorporated into SAE J300 with the objective of improving its ability to specify the oil properties necessary for good engine starting and operation at low-temperatures. The current lack of field problems related to low-temperature operation of both light- and heavy-duty vehicles provides one indication of the success with which SAE J300 meets this objective. However, the last decade has witnessed significant changes in engine design to meet more stringent emissions and fuel economy regulations. For this reason, it is time for the industry to re-evaluate the low-temperature viscosity specifications in J300 to determine if they represent the optimum values needed for modern engine designs.
Economical Design of Shelf Angles
Authors: Tide RHR , Krogstad NV
Published: March 2009

General guidelines for the design and construction of shelf angles supporting masonry veneers in high-rise buildings can be found in several published documents. Examples of shelf angles in service have been found, however, where failures did not occur even though many of these guidelines were not followed. In one such case, no significant yielding or excessive deflection was observed even though the stresses in the steel predicted by traditional analysis greatly exceeded yield stresses and the computed deflection of the angle exceeded the expansion joint width.

This paper reviews the performance of shelf angles taking into account several boundary conditions and factors that are commonly overlooked in design but that have substantial effect on the actual performance. A procedure is outlined for the economical and rational design of shelf angles. Included are procedures for the sizing of shelf angles, for determining the spacing of connections, and for designing and detailing connections to the building structure. Examples are given to show how the procedure would be used in the design process.
Frictional Characteristics of Clay Brick Pavers
Authors: Trimble BE , Kulakowski BT
Published: March 2009

The use of brick as a paving material has a long history. Over the past few years brick has again been specified in vehicular areas. Engineers are now requesting information on the skid resistance properties of brick. A research project was undertaken to determine brick's skid resistance, as well as to compare brick's frictional characteristics with those of other paving materials. It was also desired to determine if skid resistance correlated with other physical properties of brick.

Tests using the British Pendulum Tester confirmed that these brick have excellent frictional characteristics. It was also determined that skid resistance does not correlate with brick's compressive strength, abrasion index nor cold water absorption.
A Comparative Review of Various Test Meteods for Evaluating the Water Penetration Resistance of Concrete Masonry Wall Units
Authors: Driscoll ME , Gates RE
Published: March 2009

Water damage to masonry either directly or indirectly as a result of freeze-thaw action has long been a concern to the construction industry. Over the years, the industry has developed a number of tests to measure leakage in masonry walls. However, little attention has been given to the correlation between these tests and the factors that contribute to water penetration and leakage. The forces that compel liquid water from the outside of a masonry wall into the interior of the building are: capillary forces - the propensity for water to “wick” in porous materials or through hairline cracks kinetic forces - the kinetic energy of a wind-driven rain will force it into the depth of the wall pressure differential - net pressure differentials caused by ventilation and air conditioning systems may cause the water to pass through small defects in the wall gravity - under gravity water can drip in through imperfections in flashing and parapet walls surface tension - water will tend to follow an easily wet surface, even turning around corners and edges such as in soffits, shelf angles, and loose laid metal flashing.

This paper reviews the effectiveness of existing water penetration and leakage tests such as the ASTM E 514 Test Method for Water Permeance of Masonry, RILEM tube test, AAMA 501.2-83 and other similar tests in predicting the resistance of masonry walls to water penetration caused by one or more of these forces. The authors further suggest a simple test method to complement the existing ones. A theoretical treatment of these forces and their effects upon water penetration is discussed in a separate paper.
Comparison of Laboratory Freeze-Thaw Procedures
Authors: Vickers MA
Published: March 2009

The failure modes of three laboratory freeze-thaw procedures are compared with field failures. Sets of fifteen plant-fired brick were selected. Five brick from each set were subjected to each procedure.

Two omni-directional procedures were used: The Standard Method as set forth in ASTM C67, Standard Methods of Sampling and Testing Brick and Structural Clay Tile (with a 4-h cold water saturation), and a modified ASTM (with a 5-h boil saturation).

One uni-directional method was used: The Face Freeze-Thaw Procedure. This procedure was developed in the Acme Brick Company Research Laboratory, Denton, Texas, and utilizes the 5-h boil saturation. After each freeze cycle, only the face of the brick is thawed while the body remains frozen. The test specimens are withdrawn after 100 cycles, or when a specimen has failed. A sample is considered to have failed when a laminar crack develops parallel to the brick face. The crack usually develops 10–15 cycles before the face comes off.