bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Evaluation of Experimental Nonwoven Breathable Barrier Fabrics
Authors: Wadsworth LC , Salamie LM
Published: March 2009

In this study more effective methods of applying a fluorochemical finish to relatively inexpensive melt blown/spunbond (MB/SB) nonwoven laminates developed in the Textiles and Nonwovens Development Center (TANDEC) at The University of Tennessee, Knoxville (UTK) were investigated with respect to improved performance and lower cost. The two possible end-uses for the MB/SB laminates are operating room drapes and gowns and apparel for agricultural workers, such as, pesticide applicators. In addition to comparing finishing techniques, the thermal bonding sequence of a MB/SB laminate before and after finishing also was studied to determine the effects on repellency, barrier properties, laminate bonding strength, air permeability and hand.

Polypropylene melt blown webs produced on the 20-inch (0.51 m) Exxon melt blown pilot line at UTK were laminated with an experimental point bonded spunbond polypropylene fabric. Polypropylene melt blown and spunbond laminate samples were thermally bonded with a smooth roll calender both before and after fluorochemical (FC) finishing by the more conventional padding technique and by two low wet pickup methods, foam finishing and kiss roll applications. Repellency (oil, alcohol and water repellency), barrier properties (water impact resistance and air permeability), and bonding strengths were examined.

Surprisingly, the MB/SB laminates, which were thermally bonded prior to finishing, picked up substantially less finish due to decreased porosity, but had much improved oil and alcohol repellency. The foam finished laminates had the highest oil and alcohol repellency values followed by those prepared by kiss roll and finally the padding techniques. Although all of the finished MB/SB laminates had excellent water spray ratings and water impact penetration resistance (due to the barrier properties of the melt blown component), the key to oil and alcohol repellency appears to be the concentration of FC finish deposited on the outer surface of the laminate.

As would be expected, the thermally bonded laminates had lower air permeability, as compared to the unbonded laminates. The melt blown and the spunbond components separately had appreciably higher air permeability. However, the air permeability values of the MB/SB laminates, which were thermally bonded before FC finishing were generally greater than a slightly lower weight commercial spunbond/melt blown/spunbond (SMS) fabric, which had been thermally point bonded. Laminate bonding strengths were much lower than the commercial point bonded SMS fabric, but were believed to be suitable for some protective clothing applications.
Comparative Responses to Exercise-Heat Stress of Two Chemical Protective Garments
Authors: Santee WR , Cadarette BS , Schamber DW , Gonzalez RR
Published: March 2009

Rectal (Tre) temperatures, heart rates and other physiological parameters of twelve volunteer subjects were measured while walking in environmental chambers on a level treadmill at 1.34 m·s-1 for a maximum of 100 min. Subjects replicated the testing while wearing two different chemical protective (CP) garments; the US issue Battledress Overgarment (BDO) and a candidate light-weight garment (LWG). The subjects wore the garments in three environments: 18°C (65°F), 70% rh; 32°C (90°F), 50% rh; and 32°C (90°F), 80% rh. The wind speed was constant at 1.1 m·s-1 (2.5 mph). In addition to the CP garment, subjects wore an M17Al mask with M6A2 hood, underwear, socks, combat boots, and CP vinyl rubber overshoes and gloves with all closures fastened. Prior to testing, subjects drank 600 ml H2O, dressed and were weighed, then entered the chamber for a 20 min baseline prior to walking. Exercise was continuous with no scheduled breaks. Test limits for subjects were a Tre of 39°C (102°F) or a sustained heart rate of 180 bpm. Subjects also terminated voluntarily or were withdrawn by test observers. Dependent variables were total time walked (ET), δTre and Esw (evaporative water loss). Differences between uniforms were significant for ET and Esw (32°C environments only), and for δTre in all environments. In the 18°C (65°F) environment, in both garments, all subjects completed 100 min of walking. In all significant cases, subjects demonstrated less physiological strain during exercise while wearing the LWG garment relative to the BDO.
Evaluation of Carbonaceous Adsorbent Coated Fabric as a Barrier to Pesticide Penetration for Dermal Exposure Reduction in Pesticide Application
Authors: Easter EP , Koals MA
Published: March 2009

The purpose of the research was to assess the barrier protection of carbonaceous adsorbent coated fabrics to pesticide penetration using three pesticides at three levels of exposure. The fabric helsasafe® was a three component, textile/adhesive/adsorber structure, employing Ambersorb® adsorbent, a patented synthetic adsorbent resulting from pyrolysis of macroreticular polymer beads. A pesticide spray chamber delivered a controlled amount of pesticide solution to the fabric samples. The analysis was completed by extracting the pesticide residue from the fabric with hexane. High performance liquid chromotography (HPLC) analysis enabled the detection of pesticides at the ppm level. The results showed that helsasafe® 503045 and 502666 provided complete barrier protection for one pass exposure levels for all three pesticides. These two fabrics also provided complete barrier protection for two and three pass exposures of the pesticide Chlorobenzilate®. In addition, the same two fabrics provided complete barrier protection in the majority of replications for the other two pesticides at two and three pass exposures. Also, all three helsasafe® fabrics provided better barrier protection to the pesticide Terrazole® than the six denim fabrics used for comparison.
Clothing Insulation Prediction in Hypobaric Environments
Authors: Chang SKW , Gonzalez RR
Published: March 2009

An experimentally determined and theoretically derived relationship between convective heat transfer coefficient (hc) and barometric pressure (Pb) is applied to predict the clothing insulation property at hypobaric environments. The U.S. Army Research Institute of Environmental Medicine hypobaric chamber was used to simulate five environmental conditions: at elevations of 0, 1520 m, 3050 m, 4570 m, and 6100 m. Under constant wind speed and temperature in the chamber, hc was determined using the naphthalene sublimation technique. Circular naphthalene disks were placed at six body sites on a stationary, copper manikin, which models the human body anthropometrically. Naphthalene weight loss was then translated to hc using the Chilton-Colburn heat and mass transfer analogy. We found that as Pb decreased, hc decreased accordingly, pointing to a diminished convective transfer process. However, our data also showed that hc varied linearly with Pb. Previously, hc and Pb were thought to be related through a nonlinear power function. A linear hc-Pb dependency was also theoretically derived. Consequently, in hypobaric environments, the previously employed nonlinear function would overestimate hc when compared to a linear relationship. Overestimation of hc means an overestimation of the potential convective heat transfer, and thus a probable underestimation of clothing insulation. For the four hypobaric environments examined in this study, overestimations in hc translate to potential clothing insulation underestimations of 6.72%, 11.2%, 14.1%, and 16.1%. The degree of underestimation worsens in order of decreasing barometric pressure (or ascending terrestrial elevation). Hence, an exercising person dressed according to the conventional predictive model, may well be overdressed and suffer from too much heat storage rather than from the inherent cold of high altitude.
Effect of Fabric Finish on the Adhesion of Molten Metal to Wool
Authors: Proctor TD , Thompson H
Published: March 2009

The influence of the finishing of wool fabrics on the adhesion of molten zinc and molten aluminium has been determined. The factors considered were: chrome dyeing, zirpro treatment and fluorocarbon treatment. It was concluded that chrome dyeing and zirpro treatment both increase the amount of adhesion of molten zinc and aluminium, whilst the fluorocarbon treatment has the opposite effect. These findings have important implications on the design of protective clothing for use in the primary metal industries.
New Developments in the Design and Evaluation of Flame Retardant Clothing for Protection Against Molten Aluminum Splash Hazards
Authors: Sharkey R
Published: March 2009

Alcoa produces and handles millions of pounds of molten aluminum every day. Protecting employees against burns and setting their clothing on fire is a major responsibility. A number of years ago, Alcoa set out to find secondary protective clothing to prevent these potentially serious injuries. To date, many fabrics and coatings have been tested by splashing with molten aluminum and bath on the sample; After all the testing, Alcoa has decided to use a fabric where the warp is treated with a flame retardant chemical before the weaving. The fill is 100% untreated cotton. This fabric has been field tested and has performed very well. In addition, al employees that have tested the clothing have stated the clothinj is comfortable.
Instrumented Mannequin Evaluation of Thermal Protective Clothing
Authors: Dale JD , Crown EM , Ackerman MY , Leung E , Rigakis KB
Published: March 2009

An instrumented mannequin has been constructed for testing the thermal protective qualities of garments when subjected to short duration flash fires. To measure the rate of heat transfer to the mannequin surface 110 skin simulant sensors are used. The flash fires are produced with propane diffusion flames. A computer controlled data acquisition system is used to run the experiment, record and store the data, calculate the extent and nature of skin damage and display the results. The sampling rate of the system is 800 Hz. The heat fluxes used in the study were varied from 67 kW/m2 to 84 kW/m2 (1.6 cal/cm2· s to 2 cal/cm2· s), while burn durations were limited to 3 and 4 seconds.

Six different fibre/fire retardant/fabric weight combinations were tested. The results show that increasing the fabric weight for a particular fibre reduces the extent of skin burning. However some materials are more effective than others so that a general correlation of this form does not hold. Increasing the heat flux level and duration increased the predicted amount of skin burning with all the garments tested. There was a good correlation with TPP results at the low heat fluxes and durations, but not at the high values for each.
Robotic Mannequin Technology for Enhanced Product Testing
Authors: Fecht BA , Bennett DW
Published: March 2009

Engineers at Pacific Northwest Laboratory (PNL) have developed several articulated robotic mannequin systems which closely simulate human anthropometric shape, complex motion and physiological function. These systems provide highly reproducible and realistic tests which aid in the evaluation of high performance clothing, consumer products, and human comfort.
Evaluating Textiles and Apparel for Controlling Contamination in Cleanrooms
Authors: Mehta S , Hersh SP , Tucker PA , Bullerwell AG
Published: March 2009

Fabrics used in cleanroom garments must have certain characteristics. First, the fabric should not release particles into the environment; second, the fabric should contain particles shed by the body yet still be comfortable to the wearer; and third, the cost of the fabric should be as low as possible. A test method developed to evaluate some of the factors influencing the first of these characteristics is described. The number of particles generated and released from fabrics as a result of flex abrasion was measured. The flexing action was provided by a Gelbo Flex Tester which simulates to some extent the type of motion which takes place on a sleeve bent repeatedly at the elbow. The fabric sample held in the flexing portion of the tester was enclosed in an acrylic housing, and the entire system was placed in a class 10 clean air work station. The housing was then purged of ambient air before starting fabric flexing. A number of woven and nonwoven cleanroom fabrics were evaluated by counting the number of particles generated as a function of time with two aerosol particle counters. Testing to date has shown that a woven men's suiting fabric generates approximately five times as many particles as woven cleanroom fabrics. A single ply of cotton gauze generates about 20 times as many and four plies generate approximately 50 times as many particles as a typical woven cleanroom fabric.
Wash Durability of FR Cotton
Authors: Baitinger WF
Published: March 2009

Flame resistant cotton fabrics are among the most widely used fabrics for secondary protective clothing for flame and thermal exposure in the industrial work place. Technological improvements in the treating processes employed over the past ten years have yielded treated fabrics with wash durability under actual conditions that significantly outlasts the garment itself. With this paper we will provide guidelines to accurately assess factors that relate to garment service life. This paper summarizes the laboratory determination of durability, then considers actual use conditions and other parameters that may not be adequately addressed by laboratory methods. Finally practices are proposed that relate to when garments should be replaced.
Repellent Treatments on Stretchable and/or Inherently Flame Retardant Fabrics
Authors: Dix JK , DeLong BA
Published: March 2009

Five materials that were either stretchable, inherently flame retardant, or both were selected for repellent treatment. A Kermel/viscose blend, a flame retardant viscose/pbi blend, a Nomex/Kevlar blend, a Lycra/polycotton blend and a Lycra/cotton blend all exhibited excellent repellent properties (oil, water, phosphate) after treatment. Laundering of treated materials only reduced the oil repellency somewhat and had no effect on the phosphate or water repellencies. The flame retardancy was not degraded by the repellent treatment.
Protective Clothing Use in the Lawn Care Industry
Authors: Nelson CN , Lefton JL , Scott DE
Published: March 2009

In June of 1991, The State of Indiana implemented posting of lawns to which pesticides had been commercially applied. Implementation of the regulation provided a unique opportunity to track the attitudes and practices of individuals involved in the lawn care industry through a period of public policy change. This study reports the results of a survey which established a baseline of data for use in determining future changes in attitudes and practices.
Estimation of the Cost of Using Chemical Protective Clothing
Authors: Schwope AD , Renard EP
Published: March 2009

The U.S. Environmental Protection Agency, either directly or through its Superfund contractors, is a major user of chemical protective clothing. The purpose of this study was to develop estimates for the cost of using this clothing. These estimates can be used to guide purchase decisions and use practices. For example, economic guidelines would assist in decisions pertinent to single-use versus reusable clothing. Eight cost elements were considered: 1) purchase cost, 2) the number of times an item is used, 3) the number of items used per day, 4) cost of decontamination, 5) cost of inspection, 6) cost of maintenance, 7) cost of storage, and 8) cost of disposal. Estimates or assumed inputs for each of these elements were developed based on labor costs, fixed costs, and recurring costs. The cost elements were combined into an economic (mathematical) model having the single output of cost/use. By comparing cost/use for various use scenarios, conclusions are readily reached as to the optimum economics for purchase, use, and reuse of the clothing. In general, clothing should be considered disposable if its purchase cost is less than its average cost per use for the anticipated number of times it will be reused.
European Standardization of Protective Clothing
Authors: Heffels PW , Ziegenfu\ BG
Published: March 2009

European standards are required for protective clothing for the free trade of these products in the European internal market. The procedure is explained how to produce a European standard as well as the structure of the technical committee CEN/TC 162 standardizing protective clothing and gloves. Following is a detailed survey of the standard program in this committee. Preliminary results are presented concerning completed drafts, sizing, marking etc. Furthermore it is shown how the results of ISO standardization are adopted in European standardization of protective clothing.
Assessing Ecological Hazard Under TSCA: Methods and Evaluation of Data
Authors: Smrchek J , Clements R , Morcock R , Rabert W
Published: March 2009

The Environmental Effects Branch (EEB) of the United States Environmental Protection Agency (USEPA) evaluates data to assess the potential effects, inherent toxicity, and hazard posed by industrial chemicals to the environment for the Office of Pollution Prevention and Toxics or OPPT (formerly the Office of Toxic Substances or OTS) under the Toxic Substances Control Act (TSCA). The regulatory framework of TSCA focuses on data submitted by industry and reviewed by EEB. The review process is critical to assessing the ecotoxicological hazard of existing chemicals (TSCA Section 4), new or Pre-manufacture notice (PMN) chemicals (Section 5), and other potentially hazardous existing chemicals (Sections 6 and 8). EEB developed methods for hazard assessment using a tiered testing scheme, test guidelines, environmental endpoints of concern, and assessment factors. The OPPT testing scheme provides a unified, orderly, consistent, economical, and flexible strategy. It is organized into four tiers, each with several toxicity tests. Tiers increase progressively in complexity, testing costs, and duration of the tests. Decision criteria occur at intervals in the scheme and serve to facilitate making choices on whether to proceed with additional testing or to discontinue testing. OPPT test guidelines are state-of-the-art aquatic and terrestrial test methods used to measure toxicity of industrial chemicals. New guidelines (sediment toxicity tests) are promulgated in response to developments in ecotoxicity research, interest in new testing areas, and Agency needs. The testing scheme and test guidelines are used to assess the possible environmental hazard of existing chemicals and new chemicals. Available toxicity data on existing chemicals range from a moderate to a large amount, while limited data usually are available for PMN chemicals. Results of available testing are validated by EEB and incorporated into the hazard assessment. This evaluation identifies qualitative and quantitative effects that may occur from chemical exposure, reports environmental concentrations at which toxic effects may begin to occur, and marshalls arguments to support the analysis. These toxic effect concentrations are used to derive environmental concern levels. For PMN chemicals, assessment factors are used to adjust toxicity data to arrive at environmental concern levels, and to require additional testing to better assess hazard. Concern levels are then compared to predicted exposure concentrations to determine the risk of actually incurring harm, and to obtain a decision on possible regulatory action.
Environmental Risk Assessment of New Chemicals Under the Toxic Substances Control Act TSCA Section Five
Authors: Nabholz JV , Miller P , Zeeman M
Published: March 2009

The Toxic Substances Control Act (TSCA) allows for the regulation of new industrial chemicals if a chemical may present an unreasonable risk toward the environment, or if a chemical has significant exposure toward the environment. Risk assessment under TSCA Section 5 consists of the integration of the hazard assessment for a chemical with the chemical's exposure assessment.

The environmental-hazard assessment consists of identifying all of the effects of a chemical toward organisms in the environment, and toward the populations, communities, and ecosystems to which those organisms belong. Toxicity data for a chemical consists of effective concentrations (EC), which indicate the type of effect and the seriousness of that effect on a given organism at a known concentration of chemical. Effective concentrations can be based on test data or predicted using structure activity relationships (SAR). A collection of all of the ECs for a chemical is called a hazard profile or a toxicity profile.

Environmental factors which reduce the inherent toxicity of a chemical (that is, mitigation factors), as well as, enhancement factors that increase toxicity are taken into account when the hazard profile is developed.

The environmental-exposure assessment consists of predicting the environmental concentrations of a chemical from releases due to its production, processing, uses, and disposal. There are two types of exposure assessment most frequently used under TSCA: the Percen-tile Stream Flow Method and the Probability Dilution Model (PDM) Method.

Environmental-risk assessment is done by using the quotient method. This method simply compares an EC or a concern concentration (CC) to the actual or predicted environmental concentrations (PEC). If the PEC is greater than the EC or CC, then you have a potential risk.

Case studies for several types of chemicals will be presented: neutral organic chemicals; organic chemicals with excess toxicity; anionic surfactants; nonionic surfactants; cationic surfactants; amphoteric surfactants; anionic polymers; nonionic polymers; poly cationic polymers; amphoteric polymers; acid dyes; neutral dyes; cationic dyes; amphoteric dyes; polyanionic monomers; and compounds which hydrolyze (for example, acid chlorides and alkyloxysilanes); and metals.
The Use and Application of QSARs in the Office of Toxic Substances for Ecological Hazard Assessment of New Chemicals
Authors: Clements RG , Nabholz JV , Johnson DW , Zeeman M
Published: March 2009

The Office of Toxic Substances (OTS), United States Environmental Protection Agency (USEPA), is responsible for administering the Toxic Substances Control Act of 1976 (TSCA). Under Section 5 of TSCA, all new chemicals must be submitted to the USEPA for review and evaluation before entering commerce. The Environmental Effects Branch (EEB) of the Health and Environmental Review Division (HERD) is responsible for the ecological-hazard assessment of new chemicals. Submitters of new chemicals are not required to provide any ecotoxicological data. To date, less than 10% of Sec. 5 submissions contain environmental toxicity data. In the early years, the EEB used analogs, chemical class similarities and literature searches to evaluate the potential ecological hazards of new chemicals. The use of Quantitative Structure Activity Relationships (QSARs) was added to the hazard assessment process in 1981. These QSARs were applied to three broad categories of organic chemicals: (1) neutral organics that are nonreactive and nonionizable, (2) neutral organics that are reactive or ionizable organics (for example, anilines), which show excess toxicity in addition to narcosis, and (3) surface-active compounds such as surfactants and polycationic polymers. Currently, over 50 QSARs are available to estimate the toxicity of new chemicals to fish, aquatic invertebrates and algae. These QSARs can be applied to about 40 classes and subclasses of organic chemicals.

This paper describes the development and application of QSARs by the OTS in the hazard assessment of new chemicals under TSCA.
Assessment of Genetically Engineered Microorganisms Under TSCA: Considerations Prior to Use in Fermentors or Small-Scale Field Release
Authors: Sayre PG , Kough JL
Published: March 2009

The Toxic Substances Control Act (TSCA) gives the EPA Office of Toxic Substances (OTS) jurisdiction over the manufacture, processing, distribution, use, and disposal of all microbial biotechnology products intended for, or already in, commerce not specifically subject to other federal regulatory authorities. OTS reviews biotechnology products for two classes of microorganisms: those for use in closed systems, such as fermentors and those for intentional environmental release. Examples of products reviewed in OTS include enzymes, such as proteases produced by bacteria in fermentation systems and re-combinant rhizobia for enhanced nitrogen fixation in legumes. Hazard and exposure analyses are combined with other considerations into an overall risk assessment for each product. Hazard analyses focus on potential adverse human and environmental effects. Exposure analyses examine the exposure to and fate of the microbe in the environment. The elements of a risk assessment are reviewed, and specific recombinant microorganism risk assessments are discussed.
The Quotient Method of Ecological Risk Assessment and Modeling under TSCA: A Review
Authors: Rodier DJ , Mauriello DA
Published: March 2009

For regulatory purposes, ecological risk assessments should have clear and meaningful objectives. In U.S. EPA's Office of Toxic Substances (OTS), the focus of ecological risk assessments is on natural resources, which are valued by society for one or more reasons. Biotic resources can be affected by toxic substances through adverse effects on mortality, growth and development, and reproduction and by bioaccumulating through the food chain. Effects on growth and development, mortality, and reproduction are presumed to occur at the population level of organization.

In OTS, the Quotient Method of ecological-risk assessment is used. The method compares toxicological-effect concentrations with predicted or measured exposure concentrations of a toxic substance. If the ratio of the two equals or exceeds 1, a risk is inferred; below 1 there is less likelihood of a risk. The advantages of the method are that it is simple to use, is compatible with the hazard and exposure assessments conducted in OTS, and has been used extensively to regulate toxic substances. The limitations are that it cannot address taxonomic or life-stage sensitivity to a toxic substance, cannot objectively address risks at intermediate quotients (near 1), and does not articulate the consequences of certain risks such as indirect toxic effects.

Computer-simulation models can be useful tools in describing the consequences of direct and indirect toxic effects. A conceptual framework model for ecological risk assessment is presented. The use of population models such as the Risk Analysis & Management Alternatives System (RAMAS) and ecosystem modeling approaches such as the Ecosystem Uncertainty Analysis is discussed. These models are still under consideration and their mention does not constitute endorsement or recommendation.

The results of a risk assessment must be communicated clearly. The Tripartite Decision Methodology, which graphically presents the results of one or more analyses is discussed.
Effects of Acidic Growth Conditions on Systematic Characters in the Conjugating Green Algae (Zygnemataceae, Chlorophyta)
Authors: Clayton KL , Hoshaw RW , McCourt RM
Published: March 2009

Many years of acid rain have caused countless lakes throughout the world to reach a pH too low to support any animal life and often only limited types of plant life. In this report, a new acidic algal culture medium, KC-1, was developed to simulate acid lake conditions in the laboratory. This medium has the ability to maintain a pH in the range 4.0 to 5.5 by the use of ammonium sulfate (NH4)2SO4 as its primary buffer. Three filamentous strains from two genera of the green algal family Zygnemataceae (Spirogyra communis and Mougeotia transeaui) were grown in KC-1 medium to observe their morphology at low pH levels (range 4.0 to 5.5). Morphology differed markedly for all three strains, when compared to morphology of these same strains that had been maintained in nonacidic culture for up to 30 years. Differences included variations in cell width, cell length, and the structure of cell walls and the chloroplasts. These characters are critically important in species-level taxonomy, which may be complicated by effects of acid rain on phenotype.
Developmental Stability: A Sensitive Indicator of Populations Under Stress
Authors: Graham JH , Freeman DC , Emlen JM
Published: March 2009

Developmental stability can be a sensitive indicator of the physiological state of individuals in natural populations. As such, it has potential as an indicator of stress, and is inexpensive and easily measured. Moreover, it can be estimated from museum specimens or from tree cores that span the time period of the disturbance. Thus, one can identify stressed populations and monitor their recovery.

The most widely used measure of developmental stability is fluctuating asymmetry, the variance in random deviations from perfect bilateral symmetry. Fluctuating asymmetry is an outstanding measure of developmental stability because bilateral symmetry is an aspect of the individual that does not change during development (that is, a developmental invariant). We are therefore proposing three additional developmental invariants as new measures of developmental stability: phyllotaxy in plants, the equiangular spiral in snails, and the fractal dimension in both plants and animals.

The arrangement of leaves on the stem of a plant is called phyllotaxis. In many plants, leaves or leaflets are arranged opposite one another on the stem or petiole. In plants with such an arrangement, we propose that deviation from an opposite arrangement be used as a measure of developmental stability.

Many snails possess a self similar developmental invariance, the equiangular spiral. As the snail grows, the whorl of the shell increases at a constant rate. We propose that deviations from a perfect equiangular spiral be used as a measure of developmental stability.

A fractal is an object that is invariant with regard to scaling. It appears the same at both high and low magnification. Fractals are common in living organisms, and represent a form of symmetry. The branching patterns of trees, blood vessels, and nerves are all fractals, as are skull sutures in vertebrates. Growth rings of trees and fish otoliths are fractals in time. In plants and other organisms, the fractal dimension of branching describes architectural complexity. For plants, the fractal dimension is the slope of the log of branch diameter or branch length regressed on the log of branch order. Assuming that the fractal dimension is indeed a developmental invariant, then the standard error of the regression can be used as the individual asymmetry measure. These measures allow one to assess the effects of stress on both natural and artificial populations, and to establish the history of stress within the impacted area.

We present data from our own research on the effects of stress on the developmental stability of fish and plants.
Evaluation of the Ability of Alcaligenes denitrificans denitrificans CR-1 to Degrade the Riot Control Agent CR Using the Standardized Aquatic Microcosm
Authors: Landis WG , Chester NA , Haley MV
Published: March 2009

An in-depth biological and physiochemical evaluation of the utility of the Standardized Aquatic Microcosm (SAM) in the evaluation of degradative organisms has been completed. The bacterium, Alcaligenes denitrificans denitrificans, CR-1, ATCC 53957, has the ability to degrade the riot control material 1,4 dibenz oxazepine (CR) and was used as the test organism. The genus Alcaligenes is a diverse and widespread group found in various types of aquatic and terrestrial environments. In this study the microcosm system used was the SAM as developed by Taub with modifications for the purposes of this study. Four groups of treatments were used: (1) controls; (2) microcosms containing the bacteria A. denitrificans CR-1; (3) microcosms containing the toxicant CR; and (4) microcosms containing CR and A. denitrificans CR-1. Separate probes and sampling equipment were used to sample the A. denitrificans CR-1 containing bacteria and the microcosms without bacteria. The initial concentration of CR, initially 6.5 mg/L, was measured using HPLC. The population density of A. denitrificans CR-1 was followed by plating samples onto a selective CR medium. A. denitrificans CR-1 rapidly colonized the microcosms, even those without CR. CR was rapidly degraded to below the EC50/IC50 levels and detectable concentrations (1 mg/ L) within 18 days. Algal populations recovered. However, the daphnid populations did not recover before the end of the test period. The patterns of nitrogen and oxygen metabolism within the CR dosed microcosms was significantly altered. Species diversity was a poor indicator of toxicant impacts. Replicability in the SAM system was comparable to past experiments containing only toxicant. Airborne cross contamination was a significant problem due to the numerous samples taken during the course of the experiment. However, the SAM has potential as a multispecies test system for following the interactions and impacts of toxicant and degradative bacteria and for the risk assessment of novel organisms.
An Aquatic/Terrestrial Foodweb Model for Polychlorinated Biphenyls (PCBs)
Authors: Ram RN , Gillett JW
Published: March 2009

Prediction of PCB-residue distributions in biota near hazardous-waste sites and other polluted ecosystems is presently limited and may ignore food-web relationships, relies on theoretical considerations not readily extended to real systems, or fails to represent temporal/spatial variation in residues or both. A model has been developed to predict PCB exposure of different parts of an aquatic/terrestrial food web of the Erie/Ontario Lake Plain biogeographic region and its output compared to data from the GM-Akwesasne Superfund site on the St. Lawrence River.

A one-compartment pharmacokinetic model of individual species, taxa, or guilds was linked to a mass-based food web to estimate the residues over time for each element therein. Ranges of pharmacokinetic parameters (or suitable surrogates) and feeding rates from the literature or calculated from published empirical and theoretical relationships for over 300 species of vertebrates and invertebrates of the biogeographic region were used to characterize the uncertainty of estimates.

As a primary simplification, plants and invertebrates were assigned to 14 food item categories linked to abiotic PCB concentrations or to 10 guilds feeding upon these items. Vertebrates (269 species) were clustered into 110 guilds using a subroutine based on dietary overlap, habitat, feeding rate and seasonal presence. Separate summer and winter food webs were thus established for four sets of linked guilds with uncertainty defined by ranges of parameters of species included therein. Monte Carlo simulation of monthly distributions of residues in a food item were used as input to consumers. Model outputs were means and standard deviations of lognormal distributions of simulated PCB residues within guilds over a 2-year period.

The model was validated against site-specific data by using lognormally distributed abiotic PCB residues as initial values. The 95% confidence intervals of the outputs covered 89% and 100%, respectively, of measured values in 40 and 36 of 45 spp. at the site. Exceptions were largely migratory or long-lived species or samples represented by a single item.

Simulations for human beings (for example, Mohawk Indians) subsisting off this food web inferred that they are expected to develop excessive residues. Simulations of mink (largely extirpated from this biogeographic region) indicate that if 50 to 100% of their food supply comes from the system, >20% would carry lethal residues and the majority would have residues associated with reproductive failure.
Suspected Tolerance to Benzo(a)pyrene Using Chromosomal Puffing inChironomus tentans
Authors: Bentivegna CS , Cooper KR
Published: March 2009

The biomarker in this study was chromosomal puffing in the salivary glands of larval Chironomus tentans. Reduced puff size was considered an indication of decreased RNA synthesis. Larvae (third or fourth instar) were exposed to test chemicals in artificial substrate for 24 or 48 h. Chromosomes from glands of individual larva were stained with methyl green-pyronin Y. Diameters of Balbiani Rings I and II (large puffs on chromosome IV) were measured using a micrometer at 400 magnification. Experiments with benzo(a)pyrene (B(a)P) have determined a lowest observable effect level (LOEL) of 0.5 nmole; however, applied doses several orders of magnitude higher (100 nmole) did not affect puffing in approximately 40% of the larvae. The degree of response varied with the individual, and puffing was seldom inhibited completely. Actinomycin D (Act D), a known RNA synthesis inhibitor, had a LOEL of 6 nmole. Exposure to 12 nmole Act D stopped puffing completely in one hundred percent of the larvae. Therefore, this novel biomarker identified a subpopulation of individuals suspected to be tolerant to B(a)P but not Act D. Responding larvae were affected in a dose-related manner with increasing applied doses corresponding to greater reduction in puff size. Individual variation was not due to differences in uptake of H3-B(a)P equivalents or bioactivation as measured by protein bound metabolites. Interaction experiments showed that the effects of B(a)P and Act D were additive. This suggested that the compounds were inhibiting RNA synthesis through a common mode of action. Varied data found in laboratory and field studies using biomarkers could inpart be due to chemical-specific tolerance.
From Research to Routine: A Review of Toxicity Testing with Marine Molluscs
Authors: Hunt JW , Anderson BS
Published: March 2009

From the numerous and diverse studies of pollution effects on marine molluscs, a few species and techniques have emerged as suitable for routine effluent toxicity measurement. As marine mollusc toxicity testing evolves from research to routine application, it has become increasingly important to determine the reliability and repeatability of toxicity measurement, and to evaluate the degree of protection that regulations based on such measures provide for organisms that inhabit receiving waters. This paper reviews recent studies of standard mollusc protocols to estimate their inter- and intralaboratory precision, relative sensitivity, and the degree to which they currently meet proposed criteria for toxicity tests that can be used effectively in regulating effluent discharges.
A Method for Conducting Acute Toxicity Tests with the Early Life Stages of Freshwater Mussels
Authors: Johnson IC , Keller AE , Zam SG
Published: March 2009

Testing techniques to assess the acute effects of pesticides to sensitive life stages of freshwater mussels have been developed for the Ecological Effects Branch (EEB), Office of Pesticide Programs (OPP), U.S. Environmental Protection Agency (EPA). The objective of this research was to define techniques for testing freshwater mussels, and not to promote or endorse the mussel species used. The techniques developed include testing of the following early life stages: mature glochidia, recently transformed juveniles, and older juveniles.

Anodonta imbecilis was amenable to acute testing methods development for the following reasons: it is reproductively active throughout most of the year; it is easily collected in the field and maintained in the laboratory; it adapts well to artificial conditions; and the transformed juveniles do not require feeding or special conditions for short-term laboratory maintenance and testing. The acute sensitivity of these young mussels was evaluated using three pesticides. The A. imbecillis acute toxicity data obtained through these 48-h exposures show that the life stages tested are less sensitive to Cyhalothrin,® Carbaryl,® and Atrazine® than the commonly used freshwater cladoceran Daphnia magna.
A Case Study: Linking an Automated Tension Testing Machine to a Laboratory Information Management System
Authors: Heberling DT
Published: March 2009

A number of issues and problems were encountered in the course of installing an automated tension testing machine and linking it to a Laboratory Information Management System (LIMS).

Difficulty was encountered in having software written to correctly calculate certain mechanical properties of steels, for which no rigorous mathematical definitions have been standardized. Additionally, it was difficult for equipment supplier and end-user to agree on how to analyze stress-strain curves having features not addressed by existing ASTM standards.

Interlaboratory comparison studies conducted with other labs in the steel industry to verify the results of the automated test machine revealed that labs are collecting data over significantly different strain ranges for their automated determinations of n values. As a result, n values do not compare well from lab to lab.

Also discussed are other details of the automation project, benefits that have been realized, and some of the laboratory's plans for the future.

It is concluded that ASTM standards require significant revision to support automated testing—not only to address the many issues that are being brought to light by automation, but also to specify automated procedures for the determination of mechanical properties.
Data Interpretation Issues in Automated Mechanical Testing
Authors: Khan RN
Published: March 2009

Sources of errors in mechanical testing attributable to the test instrument and transducers are generally well-understood. ASTM and other standards organizations have well-defined procedures for the calibration of load, strain, and displacement transducers, and the technology for improving the accuracy of these transducers has improved greatly in recent years. However, the calculation of mechanical properties is still highly dependent on the interpretation of stress-strain curves by humans, and the variation in human judgment leads to errors which in many cases are considerably greater than the errors in the transducers used for acquiring stress-strain curves. The problem is further compounded by the fact that ASTM test procedures poorly define mechanical properties, and most of these definitions are qualitative rather than quantitative. The lack of good definitions becomes most apparent when the definitions are translated into numerical algorithms for computerized systems that try to compute mechanical properties without the benefit of human judgment. This paper presents examples of these poor definitions and explains how they can lead to substantial errors in computing mechanical properties even if the stress-strain curve is highly accurate. Definition errors in the calculation of Modulus, Yield Point, Proportional Limit, Break Point, and other commonly used mechanical properties are described. The paper concludes by presenting some computer algorithms to improve the quality and consistency of computing mechanical properties from stress-strain curves.
A Comparison of Automated Versus Manual Measurement of Total Elongation-Tension Testing
Authors: Scherrer DK
Published: March 2009

A study was conducted to compare two methods of determining the total percent elongation from standard tension tests. For each test, total percent elongation was measured by two methods: the conventional manually “measured” method where the broken specimen halves are fitted back together after the test, and the automated “extensometer” method where elongation to fracture is determined by an extensometer that is left on the specimen up to the moment of fracture.

Comparison of “measured” and “extensometer” elongation results reveals excellent agreement between the two methods. The difference between the two elongation values is generally less than 1% elongation, with the measured value normally being higher.

A model was developed that could be used to predict the “measured” elongation from the “extensometer” elongation to within 1% to 1.5% of the actual “measured” value.
A Technique for Determining Yield Point Elongation
Authors: Young JJ
Published: March 2009

A method capable of calculating the Yield Point Elongation (YPE) in an automated testing system was investigated and an algorithm for determining YPE was developed. One problem that had to be resolved before a YPE algorithm could be developed was that the definition of YPE as presented in ASTM E 6, Definitions of Terms Relating to Methods of Mechanical Testing, was based upon an informal definition of discontinuous yielding. Automation of the YPE calculation required a formal definition. Discontinuous yielding was formalized to be the region over which the stress-strain diagram exhibited points of inflection (i.e., points where the second derivative of the stress-strain diagram is equal to zero). The definition of YPE then became “the difference between the elongation at the yield point and the last inflection point.”

Given the formalized definition of discontinuous yielding, it became necessary to develop an algorithm for the calculation of first and second derivatives. This investigation centered on the use of difference equations and the use of third order polynomial approximations (cubic splines) to the sampled data. Since derivative calculations inherently increase any noise that is present in the system, the susceptibility of each of these algorithms to noise was examined by impressing a gaussian noise source onto a sinusoid. The cubic spline method was selected since it caused the least amount of noise amplification. The amount of noise rejected by the cubic spline increased with the size of the region that was fitted. However, this caused an increase in the error of the polynomial approximation. When applied to actual test data, the error in the polynomial approximation resulted in increased error in the location of the inflection points. This put a limit on the amount of noise that could be rejected.

Since the noise could not be completely eliminated, false inflection points were exhibited.Therefore it was necessary to identify and ignore these false inflections. This was accomplished by calculating the slopes at successive inflection points and comparing them to the slope of the line intersecting the origin and the point of ultimate load (i.e., the point at which the maximum load occurred after lower yield). If the slope at the inflection point was within certain bounds, specified as a percentage of the ultimate load line slope, then the inflection point was considered to be valid; otherwise, it was rejected. Once the false inflection points were eliminated, the location of the last inflection was identified and the yield point elongation was calculated.
Role of Plant Bioassays in FDA Review: Scenarios for Terrestrial Exposures
Authors: Harrass MC , Eirkson CE , Nowell LH
Published: March 2009

Plant bioassays are used to predict the effects of chemicals on terrestrial systems. However, in tiered-testing schemes, plants are tested only when introduction and fate information suggest that terrestrial exposure is probable. In this paper we discuss how information on chemical introduction and fate may trigger the need for plant toxicity tests, and how terrestrial exposure estimates are obtained and used at the U.S. Food and Drug Administration (FDA). FDA regulates chemicals used for food additives, food packaging and processing, and animal drugs and feed additives. These materials may be introduced into the environment as a result of their manufacture, use, or disposal. Information on introduction rates, environmental partitioning, and transformation is used to estimate the potential for terrestrial exposure. Described in detail are two scenarios for terrestrial exposure from application of wastewater treatment plant sludges to soils and one scenario for direct introductions of animal wastes to soils.