Management and cleanup of legacy radium-contaminated sites in the United States.

The hazards associated with radium-containing materials were largely unknown when they were first introduced into household and other products over a century ago. Radium was also originally thought to have beneficial health properties, leading to confusion amongst the public about the safety of radium in household products and food items. When the adverse health effects associated with radium were discovered and became well known, radium products became unpopular and were prohibited in some countries. In the United States, after the hazards associated with radium became known, radium was first regulated by individual states in the late 1920s and early 1930s. Later, the US Nuclear Regulatory Commission (NRC) was given a role in the regulation of discrete sources of radium with the passage of the Energy Policy Act of 2005. After passage of the Act, the NRC began to systematically identify sites around the country where radium was used and reached out to site owners to determine whether existing radium contamination could pose a risk to public health and safety and the environment. The NRC devised a graded approach in response to its new regulatory responsibilities to address potential public health and safety issues at legacy radium sites. By September 2019, the NRC had dispositioned all the sites that were identified as having potential contamination from historical radium within its regulatory purview in non-Agreement States. The staff worked with site owners and federal, state and local officials, as needed, to properly disposition the sites to ensure that each site either meets the applicable criteria for unrestricted use or has controls in place to limit access during remediation so that no site poses an unacceptable risk to public health and safety and the environment.

Extending KIDs to the Mid-IR for Future Space and Suborbital Observatories.

The galaxy evolution probe (GEP) is a concept for a probe-class space observatory to study the physical processes related to star formation over cosmic time. To do so, the mid- and far-infrared (IR) spectra of galaxies must be studied. These mid- and far-IR observations require large multi-frequency arrays, sensitive detectors. Our goal is to develop low NEP aluminum kinetic inductance detectors (KIDs) for wavelengths of 10-400  µ m for the GEP and a pathfinder long-duration balloon (GEP-B) that will perform precursor GEP science. KIDs for the lower wavelength range (10-100  µ m ) have not been previously implemented. We present an absorber design for KIDs sensitive to wavelengths of 10 µ m shown to have around 75-80% absorption efficiency through ANSYS HFSS (high-frequency structure simulator) simulations, challenges that come with optimizing our design to increase the wavelength range, initial tests on our design of fabricated 10 µ m KIDs, and theoretical NEP calculations.

Millimeter-Wave Polarimeters Using Kinetic Inductance Detectors for TolTEC and Beyond.

Microwave Kinetic Inductance Detectors (MKIDs) provide a compelling path forward to the large-format polarimeter, imaging, and spectrometer arrays needed for next-generation experiments in millimeter-wave cosmology and astronomy. We describe the development of feedhorn-coupled MKID detectors for the TolTEC millimeter-wave imaging polarimeter being constructed for the 50-meter Large Millimeter Telescope (LMT). Observations with TolTEC are planned to begin in early 2019. TolTEC will comprise ∼7,000 polarization sensitive MKIDs and will represent the first MKID arrays fabricated and deployed on monolithic 150 mm diameter silicon wafers - a critical step towards future large-scale experiments with over 105 detectors. TolTEC will operate in observational bands at 1.1, 1.4, and 2.0 mm and will use dichroic filters to define a physically independent focal plane for each passband, thus allowing the polarimeters to use simple, direct-absorption inductive structures that are impedance matched to incident radiation. This work is part of a larger program at NIST-Boulder to develop MKID-based detector technologies for use over a wide range of photon energies spanning millimeter-waves to X-rays. We present the detailed pixel layout and describe the methods, tools, and flexible design parameters that allow this solution to be optimized for use anywhere in the millimeter and sub-millimeter bands. We also present measurements of prototype devices operating in the 1.1 mm band and compare the observed optical performance to that predicted from models and simulations.

Paenibacillus larvae Phage Tripp Genome Has 378-Base-Pair Terminal Repeats.

Paenibacillus larvae bacteriophage Tripp was isolated from an American foulbrood diseased honey bee hive in North Carolina, USA. The 54,439-bp genome is 48.3% G+C, encodes 92 proteins, no tRNAs, and has 378-bp direct terminal repeats. It is currently unique in Genbank.

ICRP PUBLICATION 122: radiological protection in geological disposal of long-lived solid radioactive waste.

This report updates and consolidates previous recommendations of the International Commission on Radiological Protection (ICRP) related to solid waste disposal (ICRP, 1985, 1997b, 1998). The recommendations given apply specifically to geological disposal of long-lived solid radioactive waste. The report explains how the ICRP system of radiological protection described in Publication 103 (ICRP, 2007) can be applied in the context of the geological disposal of long-lived solid radioactive waste. Although the report is written as a standalone document, previous ICRP recommendations not dealt with in depth in the report are still valid. The 2007 ICRP system of radiological protection evolves from the previous process-based protection approach relying on the distinction between practices and interventions by moving to an approach based on the distinction between three types of exposure situation: planned, emergency and existing. The Recommendations maintains the Commission's three fundamental principles of radiological protection namely: justification, optimisation of protection and the application of dose limits. They also maintain the current individual dose limits for effective dose and equivalent dose from all regulated sources in planned exposure situations. They re-enforce the principle of optimisation of radiological protection, which applies in a similar way to all exposure situations, subject to restrictions on individual doses: constraints for planned exposure situations, and reference levels for emergency and existing exposure situations. The Recommendations also include an approach for developing a framework to demonstrate radiological protection of the environment. This report describes the different stages in the life time of a geological disposal facility, and addresses the application of relevant radiological protection principles for each stage depending on the various exposure situations that can be encountered. In particular, the crucial factor that influences the application of the protection system over the different phases in the life time of a disposal facility is the level of oversight or 'watchful care' that is present. The level of oversight affects the capability to control the source, i.e. the waste and the repository, and to avoid or reduce potential exposures. Three main time frames are considered: time of direct oversight, when the disposal facility is being implemented and is under active supervision; time of indirect oversight, when the disposal facility is sealed and oversight is being exercised by regulators or special administrative bodies or society at large to provide additional assurance on behalf of society; and time of no oversight, when oversight is no longer exercised in case memory of the disposal facility is lost.

Web-based training course for evaluating radiological dose assessment in NRC's license termination process.

As part of the requirement for terminating the licenses of nuclear power plants or other nuclear facilities, license termination plans or decommissioning plans are submitted by the licensee to the U.S. Nuclear Regulatory Commission (NRC) for review and approval. Decommissioning plans generally refer to the decommissioning of nonreactor facilities, while license termination plans specifically refer to the decommissioning of nuclear reactor facilities. To provide a uniform and consistent review of dose modeling aspects of these plans and to address NRC-wide knowledge management issues, the NRC, in 2006, commissioned Argonne National Laboratory to develop a Web-based training course on reviewing radiological dose assessments for license termination. The course, which had first been developed in 2005 to target specific aspects of the review processes for license termination plans and decommissioning plans, evolved from a live classroom course into a Web-based training course in 2006. The objective of the Web-based training course is to train NRC staff members (who have various relevant job functions and are located at headquarters, regional offices, and site locations) to conduct an effective review of dose modeling in accordance with the latest NRC guidance, including NUREG-1757, Volumes 1 and 2. The exact size of the staff population who will receive the training has not yet been accurately determined but will depend on various factors such as the decommissioning activities at the NRC. This Web-based training course is designed to give NRC staff members modern, flexible access to training. To this end, the course is divided into 16 modules: 9 core modules that deal with basic topics, and 7 advanced modules that deal with complex issues or job-specific topics. The core and advanced modules are tailored to various NRC staff members with different job functions. The Web-based system uses the commercially available software Articulate, which incorporates audio, video, and animation in slide presentations and has glossary, document search, and Internet connectivity features. The training course has been implemented on an NRC system that allows staff members to register, select courses, track records, and self-administer quizzes.

The use of bioaccumulation, biomarkers and histopathology diseases in Procambarus clarkii to establish bioavailability of Cd and Zn after a mining spill.

Individuals of the crayfish Procambarus clarkii (males and females) were exposed simultaneously to cadmium and zinc during 21 days. Exposure concentrations were those determined at the Guadiamar river after the Aznalcóllar mining spill (SW, Spain): 10 and 30 microg L(-1) of cadmium and 1000 and 3000 microg L(-1) of zinc. Three biomarkers (MT: metallothioneins like proteins, VTG: vitellogenin/vitellin like proteins and histopathology) together with heavy metal bioaccumulation were determined in soft tissues of male and female P. clarkii. At the concentrations tested, increasing cadmium exposure resulted in increasing cadmium bioaccumulation and increasing subletal effects (induction of MT, VTG and histopathological damage in tissues). Nevertheless, although increasing zinc exposure showed increasing VTG induction and histopathological damages, not a positive relationship was determined with MT induction. Concerning to responses determined in male and female crayfishes only differences were found between sexes at the highest cadmium exposure concentration related to bioaccumulation in hepatopancreas tissues. Biomarkers responses to heavy metal contamination in this crayfish, even VTG induction not before tested in heavy metal contamination assessment in crustaceans resulted potential tools for the monitoring of heavy metal environmental contamination.

Use of contaminated well water, example reference biospheres 1 and 2A.

The BIOMASS programme's Theme 1 evaluated a number of scenarios, which assisted in the development of practical guidance. A total of four Example Reference Biospheres were fully developed, with the assumptions, data, and models thoroughly documented. These Examples display both the practicality and the transparency available through the use of the Reference Biosphere Methodology. While the methodology is designed to promote transparency and traceability, proper documentation and justification is still the responsibility of the user. The Examples can also be used as generic analyses in some situations. Although it is anticipated that each of the Reference Biospheres explored within BIOMASS Theme 1 should be a useful practical example, the quantitative results of the model calculations are not intended to be understood as prescribed biosphere 'conversion factors'. In choosing to implement an Example, careful consideration would need to be given to their relevance (including associated data) to the particular assessment context at hand. In general, the more complex the model is, the more limited applicability it has for generic purposes. For example, ERB1A (direct use of well water for drinking) can be used straightforwardly, with minor or no adjustments, at a number of generic sites. Example 2A, however, for which climatic conditions and agricultural practices need to be specified, would need to be implemented for each specific situation.

Comparative embryonic and larval developmental responses of estuarine shrimp (Palaemonetes pugio) to the juvenile hormone agonist fenoxycarb.

Grass shrimp (Palaemonetes pugio) were reared separately through both embryonic and total larval development during exposure to fenoxycarb at measured concentrations of <2.2 to 888 microg L(-1). A fenoxycarb concentration of 888 microg L(-1) significantly (p < 0.05) inhibited embryonic development to larval hatching and extended the embryonic developmental period from 11.9 to 12.7 days. Exposure to fenoxycarb concentrations < or = 502 microg L(-1) had no significant (p > 0.05) effect on complete embryonic development. Significantly fewer shrimp successfully metamorphosed to postlarvae when exposed through complete larval development to fenoxycarb concentrations > or = 4 microg L(-1). Larval development of grass shrimp was therefore >2 orders of magnitude more sensitive to this juvenile hormone agonist than was embryonic development. Viability of larvae developing in fenoxycarb was concentration dependent. Development beyond third zoeal stage was significantly inhibited at fenoxycarb concentrations > or = 190 microg L(-1), whereas development beyond fourth zoeal stage was inhibited by a concentration of > or = 45 microg L(-1). Fenoxycarb exposure of developing larvae did not alter either the duration of total larval development or the total number of larval stages before metamorphosis. Rearing of fenoxycarb-exposed embryos through larval development without further exposure had no significant effect on number of larval stages, larval development rate, or metamorphic success of larvae. Similarities in the sensitivity of grass shrimp larvae and mosquito larvae to fenoxycarb suggests that the use of a bioassay protocol measuring the metamorphic success of crustacean larvae would be a valuable adjunct to the hazard assessment of newly developed pesticides that target endocrine control of metamorphosis in insects and possibly other endocrine-disrupting xenobiotics as well.

Effects of fenoxycarb exposure on complete larval development of the xanthid crab, Rhithropanopeus harrisii.

Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 microg fenoxycarb/l and in megalopae exposed to 48 microg fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments 48 microg/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to >/=48 microg/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary.

Effects of fractions from biodegraded Alaska North Slope crude oil on embryonic inland silversides, Menidia beryllina.

Embryonic inland silversides, Meinida beryllina, were exposed to neutral, water-soluble fractions (WSFs) resulting from microbial degradation of artificially weathered Alaska North Slope (ANS) crude oil. Three individual microbes obtained from Prince William Sound, Alaska, and designated Phe#6 (enriched on phenanthrene), Hexaco#2 (enriched on the straight-chain alkane, hexacosane), and EI2V (grown by enrichment on Bushnell-Haas medium containing 0.2% pristane, a branched alkane) were used to individually biodegrade weathered ANS crude oil for 14 days in darkness in 20-L glass carboys containing nutrient enriched, sterilized 20% salinity sea water at 20 +/- 1 degrees C. Neutral WSFs resulting from biodegradation of ANS (lot 521) by each microbe were recovered and weighted. Neutral WSFs recovered were: 1.76 mg/L for Phe#6, 1.85 mg/L for Hexaco#2, and 13.02 mg/L for the EI2V microbe. Embryo toxicity and teratogenicity tests revealed that exposure of embryos to the WSFs from the EI2V incubation (with a total recovered neutral fraction approximately seven times greater than the Phe#6 and Hexaco#2 incubations) resulted in the most severe responses in craniofacial, cardiovascular, and skeletal organ systems. The total neutral WSFs recovered from the EI2V biodegradation of weathered ANS 521 were subfractionated into saturated (eluted with hexane), aromatic (eluted with CH2Cl2), polar (eluted with ethyl ether), and recombined (saturated + aromatic + polar) fractions. Developing fish embryos were then exposed to each subfraction and the recombined subfractions. The polar subfraction and recombined subfractions proved to be the most embryo toxic and teratogenic. They resulted in statistically significant (p < or = 0.05) responses (compared to controls) for craniofacial, cardiovascular, skeletal, and total severity effects in one or both tests with these subfractions.

Tracheostomy: a risk factor for mediastinitis after cardiac operation.

BACKGROUND: We studied whether tracheostomy after coronary artery bypass grafting (CABG) is associated with higher incidence of mediastinitis and mortality, and whether shorter intervals between median sternotomy and tracheotomy are associated with higher incidence of mediastinitis. METHODS: Patients (n = 6,057) undergoing CABG since March 1977 were reviewed. Patients requiring tracheostomy and those developing mediastinitis were identified. Mediastinitis diagnosis required positive culture of mediastinal tissue or fluid. RESULTS: After CABG, 88 patients had tracheostomy performed (1.45%). Seven patients receiving tracheostomy after developing mediastinitis were excluded. Of the remaining 81 patients, 7 developed mediastinitis (8.6%) compared with 44 of 5,969 (0.7%) who did not require tracheostomy (p < 0.001). Mortality in tracheostomy patients was 24.7% (20 of 81) compared with 5.2% in patients not requiring tracheostomy (316 of 5,969; p < 0.001). Patients not developing mediastinitis had tracheostomy placement an average of 25 days after CABG compared with 18.7 days for those developing mediastinitis (p = 0.141). CONCLUSIONS: Tracheostomy after CABG is associated with increased incidence of mediastinitis and mortality. In this review, the time interval between CABG and tracheostomy was not predictive of mediastinitis. A larger sample size would be required to be confident that there is no correlation.

Ontogenetic changes in biochemical composition during larval and early postlarval development of Lepidophthalmus louisianensis, a ghost shrimp with abbreviated development.

Changes in growth and biochemical composition during the transition from egg through zoea to decapodid in the ghost shrimp, Lepidophthalmus louisianensis (Schmitt, 1935), were documented in terms of dry weight, lipid classes, fatty acid composition, and carbon to nitrogen (C:N) ratios. Larvae of the ghost shrimp were mass-reared in the laboratory (28 degrees C; 20% S) from hatching to the decapodid stage. latroscan lipid class analysis revealed that major lipid classes in recently produced eggs were phospholipids (80.8 +/- 1.3%) and triglycerides (16.0 +/- 1.1%), which decreased during the incubation period. Polar lipids (zoea 1: 77.4 +/- 1.7%; zoea II: 77.5 +/- 2.1%; decapodid: 80.0 +/- 1.7%) and neutral lipids, of which free fatty acids (zoea I: 10.5 +/- 2.7%; zoea II: 13.1 +/- 5.2%; decapodid: 7.8 +/- 2.1%) were dominant, represented the major lipid classes in the zoeal and decapodid stages. Triglycerides were present in small amounts. The predominant fatty acids of L. louisianensis eggs, zoeae and decapodids were palmitic (16:0), stearic (18:0), eicosapentaenoic (20:5omega3), oleic (18:1omega9), and arachidonic (20:4omega6). Elemental composition of eggs, larvae, and the decapodid stage revealed conspicuous changes in the C:N ratio, with N being relatively stable during larval development but C decreasing during the decapodid stage. These data suggest independence of newly hatched L. louisianensis on external energy resources. This combined with the ability to incorporate saturated fatty acids into polar lipids provides a selective advantage for fast development of new tissue and growth, characteristic of decapod crustacean larvae with lecithotrophic development.

Growth, lipid class and fatty acid composition in juvenile mud crabs (Rhithropanopeus harrisii ) following larval exposure to Fenoxycarb, insect juvenile hormone analog.

This study examines the effects of Fenoxycarb on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations from 1 to 100 microg/l. In first crabs of R. harrisii, dry weight (microg) decreased significantly (P < 0.05) from 228.8+/-38.2 microg (n = 9) in the controls to 131.8+/-10.1 microg (n = 4) in animals exposed throughout larval development to 100 microg/l. A significant (P < 0.05) reduction was found between total lipid content in the controls and first crabs reared at concentrations greater than 50 microg/l. In relative terms (% dry weight), different lipid classes predominated in the controls and the various fenoxycarb exposure concentrations. There were no significant (P > 0.05) differences among the treatment groups in phospholipid level, while the triglyceride content was significantly lower in crabs exposed to 10 and 100 microg/l. No significant differences in the percent of free fatty acids were found in crabs exposed to 1-10 microg/l and the controls. Free sterols in crabs exposed to concentrations higher than 10 microg/l were below the detection limit. Control animal fatty acid profiles were dominated by palmitic, stearic, and oleic acid, accounting for 48% of total fatty acids (TFA). The fatty acid composition of crabs exposed to 100 microg/l significantly (P < 0.05) differed from the controls. The results suggest that fenoxycarb has substantial effects on growth, lipid class and fatty acid composition in developing larvae of R. harrisii at water concentrations greater than 10 microg/l.

Centrifugal pumps: description of devices and surgical techniques.

BACKGROUND: Because of simplicity of application, universal access, and low cost, centrifugal pumps are commonly used for short-term mechanical cardiac assist. Indications and techniques for application of this technology continue to evolve. METHODS: The clinical experience with 151 patients undergoing centrifugal mechanical cardiac assist at the University of Missouri-Columbia has been reviewed. We have compared commonly available centrifugal pumping systems in vitro and in vivo for characteristics that might distinguish them. RESULTS: Centrifugal pumps have been found to be well suited for use in surgery on the thoracic aorta, for extracorporeal membrane oxygenation and for postcardiotomy cardiac mechanical assist. Complications associated with centrifugal mechanical assist are predictable and common but potentially can be reduced by improved surgical techniques and anticoagulation strategies. In vitro and in vivo experimentation with available centrifugal pumps reveals nuances characteristic of each of the devices. CONCLUSIONS: All centrifugal pumps presently available are less destructive to blood cellular elements compared with roller pumps. With familiarity, all can function satisfactorily for short-term mechanical assist with no compelling evidence that favors any particular centrifugal pump system clinically available. Centrifugal pumps are ideally suited for left heart bypass during surgery on a thoracic aorta and for short-term application as may be required for postcardiotomy mechanical assist. Centrifugal pump technology should be part of the armamentarium of all cardiothoracic surgeons.

Tear mixing under a soft contact lens: effects of lens diameter.

PURPOSE: Tear exchange under a soft contact lens is modest, and higher exchange rates may be necessary to reduce extended-wear complications; what is not known is the optimal soft lens design to increase tear mixing. We explored the effect of lens diameter on tear mixing. METHODS: Twenty-three subjects wore four different soft contact lenses with diameters of 12.0, 12.5, 13.0, and 13.5 mm. Tear mixing was quantified by placing fluorescein isothiocyanate-dextran on the posterior lens surface, inserting the lens, and monitoring the changes in fluorescence intensity in the postlens tear film. Tear mixing, expressed as the percentage decrease in fluorescence intensity per blink, was estimated using an exponential model. Lens movement was videotaped and lens comfort was graded on a 50-point scale (50 = excellent comfort). Subjects reporting a comfort level of less than 35 were excluded. RESULTS: The mean +/- SE tear mixing rates were 1.82% +/- 0.17%, 1.61% +/- 0.16%, 1.34% +/- 0.17%, and 1.24% +/- 0.17% per blink for the 12.0-, 12.5-, 13.0-, and 13.5-mm diameter lenses, respectively. By regression analysis we found that, on average, mixing under the 12.0-mm lens was 0.59% per blink greater than with the 13.5-mm lens (P = .0024). Lens diameter was a significant predictor of lens comfort, and adjusting for the effects of comfort weakened the relationship between diameter and tear replenishment rate, although the mean rate under the 12.0-mm lens was still 0.43% per blink greater than with the 13.5-mm lens (P = .0468). CONCLUSIONS: These data suggest that smaller-diameter soft lenses provide substantially better tear mixing than larger lenses; however, even small lenses provide modest tear mixing compared with rigid contact lenses.

Effects of hypoxia on corneal epithelial permeability.

PURPOSE: Epithelial permeability to fluorescein (Pdc) increases with closed-eye soft contact lens wear. Possible mechanisms responsible for this change include corneal hypoxia (and acidosis) during overnight wear and interference of the lens with normal tear exchange. In this study we used a local environmental chamber to examine the effects of hypoxia on Pdc. METHODS: After baseline slit-lamp examination, autofluorescence, and central corneal thickness measurements, 35 subjects were fitted with a pair of airtight swimming goggles. One eye was exposed to a humidified gas mixture containing 95% nitrogen (N2) and 5% carbon dioxide (CO2), and the fellow (control) eye was exposed to air. The experimental eye and the eye measured first were assigned using a randomized block design. After the subjects wore the goggles for 1 hour, corneal thickness measurements were repeated and Pdc was assessed as previously described. A final slit-lamp examination was performed by a masked examiner to assess epithelial integrity. RESULTS: There was no significant difference in the mean ln(Pdc) (95% confidence interval) for eyes exposed to N2/CO2 when compared with paired eyes exposed to air (-2.70 [-2.99, -2.41] vs -2.51 [-2.72, -2.30] ln[nm/sec], P = .272). Although there was also no substantial difference in the slit-lamp appearance of the experimental and control eyes, the mean (95% confidence interval) change in corneal thickness for the hypoxic eyes was 19.78 (15.72, 23.84) microm compared with 3.40 (-0.67, 7.47) microm (P < .0001) in the control eyes. CONCLUSION: One hour of hypoxia caused a significant increase in corneal thickness with no apparent change in Pdc. This suggests that other factors, either alone or in combination with hypoxia, may be responsible for increased Pdc during closed-eye contact lens wear.

Altered growth and metabolism of an estuarine shrimp (Palaemonetes pugio) during and after metamorphosis onto fenvalerate-laden sediment.

Dry weight (W), carbon (C), nitrogen (N), and energy (E) (calculated) accumulation were measured in the estuarine grass shrimp, Palaemonetes pugio, throughout larval development and during the first 2 weeks as postlarvae in seawater over sediment containing the pyrethroid insecticide fenvalerate (SCF; nominal concentrations of 1, 10, and 100 microgram fenvalerate kg-1 sediment). The influence of fenvalerate-laden sediment on shrimp growth and utilization patterns of C, N, and E was dependent on fenvalerate concentration, age of shrimp, and whether shrimp were premetamorphic or postmetamorphic in development. The fenvalerate concentration in the sediment, which ultimately inhibited larval metamorphosis (100 microgram fenvalerate kg-1 sediment), significantly reduced W accumulation in developing larvae and in postlarvae growing on the sediment for an equivalent time. Accumulation of C, N, and E varied not only with concentration of SCF, but differed between pelagic larvae developing in water above SCF and newly settled postlarvae growing in direct contact with SCF. Larvae developing above >/=10 microgram kg-1 SCF contained significantly less N, while postlarval shrimp settling onto >/=10 microgram kg-1 SCF accumulated significantly less C and E. Measurable variations in growth and energy reserves of toxicant-sensitive life stages in response to environmentally realistic insecticide exposures have a direct link to ecological consequences of toxic stress and may be useful as biomarkers to diagnose early damage in estuarine populations.

Day to day variations in ocular surface staining of the bulbar conjunctiva.

PURPOSE: The purpose of this study was to characterize the variability of bulbar conjunctival staining over time in response to a single application of fluorescein. METHODS: Sixteen subjects were stained Monday through Friday for a 2-week period. Appointments were scheduled from 9:00 a.m. to 12:00 p.m. to minimize variance due to diurnal variation. Fluorescein stain was applied by touching a separate Ful-Glo strip wetted with nonpreserved saline to the lower palpebral conjunctiva of each eye, with the right eye being stained first. Immediately after application of the fluorescein, conjunctival staining was graded in a randomized order by two examiners, using cobalt blue illumination and a no. 15 Wratten enhancement filter. Conjunctival staining was assessed based upon a 0 to 4 grading scale with 0.5 grade increments. By evaluating the variability in staining over time for each subject, a representation of overall fluctuation for the group was obtained. RESULTS: The average duration for an episode of staining graded higher than the group median (grade 0.5) was found to be 2.0 +/- 2.4 days. Overall, a mean staining grade of 0.5 for the right eye and 0.6 for the left eye was found. Right and left eyes were found to correlate well (r = 0.67, p < 0.01, Spearman's correlation) and the mean difference was not statistically significant [p = 0.73, multi-way, repeated measures analysis of variance (ANOVA)]. The mean difference in grading between the two examiners was 0.1 grades (p = 0.67, multi-way, repeated measures ANOVA), with a correlation coefficient of r = 0.68 (p < 0.01, Spearman's correlation). CONCLUSIONS: Characterization of conjunctival staining over time may be useful in evaluating clinically suspect staining, and in determining its potential duration. The appearance and variability of the conjunctival staining patterns noted in this study indicate a potential relationship to normal physiological processes, such as desquamation. This study also demonstrated a low amount of variability between right and left eyes, supporting the use of contralateral studies in the assessment of conjunctival staining. It also demonstrated a good consistency between separate examiners despite not being standardized.

Preliminary observations on responses of embryonic and larval Pacific herring, Clupea pallasi, to neutral fraction biodegradation products of weathered Alaska North Slope oil.

Weathered Alaska North Slope crude oil (ANS 521) was subjected to biodegradation in vigorously stirred incubations for 14 days at 15 +/- 1 degrees C in 20/1000 salinity sterilized seawater, amended with nutrients and inoculated with a hydrocarbon-degrading microorganism (EI2V) isolated from an oil-contaminated beach in Prince William Sound, Alaska. A total of 13.7 mg/L water-soluble neutral fraction (WSF) was recovered from the incubation of weathered ANS 521. Toxicity/ teratogenicity tests were conducted with WSF recovered from the biodegradation system using embryonic and larval Pacific herring, Clupea pallasi. Exposures were begun at 4, 48, and 96 h postfertilization of herring eggs. Exposure concentrations were 1, 10, and 100% of the original concentration of WSF recovered from incubations (redissolved in 20/1000 salinity sterile seawater at 15 +/- 1 degrees C). Sterile 20/1000 salinity seawater without the addition of redissolved neutral fraction was used as a control. Significant (p < or = 0.05) embryo mortality or teratogenic responses were observed at WSF concentrations of 10 and 100%. On days 5 through 8 of embryogenesis, counts of heart contraction rates were significantly lower (p < or = 0.05) at the 100% WSF concentration for embryos exposed beginning at 4 and 48 h postfertilization. Grow-out of larvae from selected exposures was conducted. High mortality was noted in larvae exposed to the 10% WSF concentration beginning at 4 and 48 h postfertilization. Most of these larvae died 5 to 8 days after hatching when they elicited vertebral displacements at a time concurrent with the onset of feeding behavior.