Time-resolved X-ray diffraction diagnostic development for the National Ignition Facility.

We present the development of an experimental platform that can collect four frames of x-ray diffraction data along a single line of sight during laser-driven, dynamic-compression experiments at the National Ignition Facility. The platform is comprised of a diagnostic imager built around ultrafast sensors with a 2-ns integration time, a custom target assembly that serves also to shield the imager, and a 10-ns duration, quasi-monochromatic x-ray source produced by laser-generated plasma. We demonstrate the performance with diffraction data for Pb ramp compressed to 150 GPa and illuminated by a Ge x-ray source that produces ∼7 × 1011, 10.25-keV photons/ns at the 400 µm diameter sample.

Crystal response measurement of the x-ray transmission crystals used by the Imaging Spectroscopy Snout at the National Ignition Facility.

The Imaging Spectroscopy Snout (ISS) used at the National Ignition Facility is able to simultaneously collect neutron pinhole images, 1D spatially resolved x-ray spectra, and time resolved x-ray pinhole images. To measure the x-ray spectra, the ISS can be equipped with up to four different transmission crystals, each offering different energy ranges from ∼7.5 to ∼12 keV and different resolutions. Characterizing and calibrating such instruments is of paramount importance in order to extract meaningful results from experiments. More specifically, we characterized different ISS transmission-type alpha-Quartz crystals by measuring their responses as a function of photon energy, from which we inferred the angle-integrated reflectivity for each crystal's working reflections. These measurements were made at the Lawrence Livermore National Laboratory calibration station dedicated to the characterization of x-ray spectrometers. The sources used covered a wide x-ray range-from a few to 30 keV; the source diameter was ∼0.6 mm. The experimental results are discussed alongside theoretical calculations using the pyTTE model.

Comparison of a novel passive sampler to standard water-column sampling for organic contaminants associated with wastewater effluents entering a New Jersey stream.

Four water samples collected using standard depth and width water-column sampling methodology were compared to an innovative passive, in situ, sampler (the polar organic chemical integrative sampler or POCIS) for the detection of 96 organic wastewater-related contaminants (OWCs) in a stream that receives agricultural, municipal, and industrial wastewaters. Thirty-two OWCs were identified in POCIS extracts whereas 9-24 were identified in individual water-column samples demonstrating the utility of POCIS for identifying contaminants whose occurrence are transient or whose concentrations are below routine analytical detection limits. Overall, 10 OWCs were identified exclusively in the POCIS extracts and only six solely identified in the water-column samples, however, repetitive water samples taken using the standard method during the POCIS deployment period required multiple trips to the sampling site and an increased number of samples to store, process, and analyze. Due to the greater number of OWCs detected in the POCIS extracts as compared to individual water-column samples, the ease of performing a single deployment as compared to collecting and processing multiple water samples, the greater mass of chemical residues sequestered, and the ability to detect chemicals which dissipate quickly, the passive sampling technique offers an efficient and effective alternative for detecting OWCs in our waterways for wastewater contaminants.

Polar organic chemical integrative sampling and liquid chromatography-electrospray/ion-trap mass spectrometry for assessing selected prescription and illicit drugs in treated sewage effluents.

The purpose of the research presented in this paper was twofold: (1) to demonstrate the coupling of two state-of-the-art techniques: a time-weighted polar organic chemical integrative sampler (POCIS) and microliquid chromatography-electrospray/ion-trap mass spectrometry and (2) to assess the ability of these methodologies to detect six drugs (azithromycin, fluoxetine, omeprazole, levothyroxine, methamphetamine, methylenedioxymethamphetamine [MDMA]) in a real-world environment, e.g., waste water effluent. In the effluent from three wastewater treatment plants (WWTPs), azithromycin was detected at concentrations ranging from 15 to 66 ng/L, which is equivalent to a total annual release of 1 to 4 kg into receiving waters. Detected and confirmed in the effluent from two WWTPs were two illicit drugs, methamphetamine and MDMA, at 2 and 0.5 ng/L, respectively. Although the ecotoxicologic significance of drugs in environmental matrices, particularly water, has not been closely examined, it can only be surmised that these substances have the potential to adversely affect biota that are continuously exposed to them even at very low levels. The potential for chronic effects on human health is also unknown but of increasing concern because of the multiuse character of water, particularly in densely populated, arid areas.

A holistic passive integrative sampling approach for assessing the presence and potential impacts of waterborne environmental contaminants.

As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipermeable membrane device has gained widespread use for sampling hydrophobic chemicals from water and air, the polar organic chemical integrative sampler is applicable for sequestering waterborne hydrophilic organic chemicals, the stabilized liquid membrane device is used to integratively sample waterborne ionic metals, and the passive integrative mercury sampler is applicable for sampling vapor phase or dissolved neutral mercury species. This suite of integrative samplers forms the basis for a new passive sampling approach for assessing the presence and potential toxicological significance of a broad spectrum of environmental contaminants. In a proof-of-concept study, three of our four passive integrative samplers were used to assess the presence of a wide variety of contaminants in the waters of a constructed wetland, and to determine the effectiveness of the constructed wetland in removing contaminants. The wetland is used for final polishing of secondary-treatment municipal wastewater and the effluent is used as a source of water for a state wildlife area. Numerous contaminants, including organochlorine pesticides, polycyclic aromatic hydrocarbons, organophosphate pesticides, and pharmaceutical chemicals (e.g., ibuprofen, oxindole, etc.) were detected in the wastewater. Herein we summarize the results of the analysis of the field-deployed samplers and demonstrate the utility of this holistic approach.

Purification of triolein for use in semipermeable membrane devices (SPMDs).

Analyses of triolein-containing semipermeable membrane devices (SPMDs) have sometimes been impeded by interferences caused by impurities endemic to triolein that codialyze with the analytes. Oleic acid and methyl oleate have been the most troublesome of these impurities because of their relatively high concentrations in triolein and because significant residues of both can persist even after size exclusion chromatographic (SEC) fractionation. These residues have also been blamed for false-positive signals during bioindicator testing of SPMD dialysates. To prevent these problems, a simple, cost-effective procedure was developed for purifying triolein destined for use in SPMDs: the bulk triolein is repeatedly (6x) partitioned against methanol. Tests of the procedure show that 14C-oleic acid is completely removed from the triolein. After SEC fractionation, dialysates of standard-size SPMDs made with the purified triolein contain less than 5 microg of methyl oleate as compared to sometimes more than 500 microg for dialysates (also after SEC) of SPMDs made with unpurified triolein. Gas chromatographic analyses with flame ionization and electron capture detection show that the purification treatment also greatly reduces the number and size of peaks caused by unidentified contaminants in the triolein. Microtox basic assay of dialysates of SPMDs shows that those made with the purified triolein have lower acute toxicities than dialysates of SPMDs made with unpurified triolein. Yeast estrogen screen (YES) testing of SPMDs fabricated with unpurified and purified triolein demonstrates that the purification process removes all background estrogenic activity.

Comparisons of coarse and fine versions of two carbons for reducing the bioavailabilities of sediment-bound hydrophobic organic contaminants.

Coarse (whole) and finely ground Ambersorb 1500 and coarse and fine coconut charcoal were compared as to their efficiencies in scavenging organic contaminants desorbed from sediment. Aqueous slurries of a test sediment spiked (1 ppm) with p,p(')-DDE (DDE), 2,2('),5,5(')-tetrachlorobiphenyl (TCB), naphthalene (NAP), or phenanthrene (PHEN), and containing 1% levels of the test carbons were treated by shaking at 35 degrees C while exposed to clusters of low-density polyethylene membrane (detox spiders). Controls consisted of spiked sediments and detox spiders but no added carbon of any kind and thus represented unimpeded bioavailabilities (to the spiders). After the treatments--agitation periods from 2.5 to 60 h, depending on contaminant hydrophobicity--the exposed detox spiders were analyzed. The fine carbon of either type was more effective than its coarser variant in obstructing contaminant bioavailabilities. The finer variants of both carbons obstructed the bioavailabilities of NAP and PHEN equally well as did the coarser variants of both. Whole Ambersorb 1500 and coarse coconut charcoal were similarly ineffective in intercepting TCB and DDE. Ground Ambersorb 1500 obstructed virtually all bioavailability of all four contaminants and was far more effective than fine coconut charcoal in intercepting DDE and TCB. An additional experiment compared the effectiveness of ground Ambersorb 1500 and fine coconut charcoal in obstructing the bioavailabilities from sediment of a broad array of spiked organochlorine pesticides. The performance of ground Ambersorb 1500 was again found to be superior; the bioavailable levels of each of the 27 pesticides were markedly lower in the presence of ground Ambersorb 1500 than in the presence of fine coconut charcoal.

An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests.

As an integral part of our continued development of water quality assessment approaches, we combined integrative sampling, instrumental analysis of widely occurring anthropogenic contaminants, and the application of a suite of bioindicator tests as a specific part of a broader survey of ecological conditions, species diversity, and habitat quality in the Santa Cruz River in Arizona, USA. Lipid-containing semipermeable membrane devices (SPMDs) were employed to sequester waterborne hydrophobic chemicals. Instrumental analysis and a suite of bioindicator tests were used to determine the presence and potential toxicological relevance of mixtures of bioavailable chemicals in two major water sources of the Santa Cruz River. The SPMDs were deployed at two sites; the effluent weir of the International Wastewater Treatment Plant (IWWTP) and the Nogales Wash. Both of these systems empty into the Santa Cruz River and the IWWTP effluent is a potential source of water for a constructed wetland complex. Analysis of the SPMD sample extracts revealed the presence of organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The bioindicator tests demonstrated increased liver enzyme activity, perturbation of neurotransmitter systems and potential endocrine disrupting effects (vitellogenin induction) in fish exposed to the extracts. With increasing global demands on limited water resources, the approach described herein provides an assessment paradigm applicable to determining the quality of water in a broad range of aquatic systems.

Considerations involved with the use of semipermeable membrane devices for monitoring environmental contaminants.

Semipermeable membrane devices (SPMDs) are used with increasing frequency, and throughout the world as samplers of organic contaminants. The devices can be used to detect a variety of lipophilic chemicals in water, sediment/soil, and air. SPMDs are designed to sample nonpolar, hydrophobic chemicals. The maximum concentration factor achievable for a particular chemical is proportional to its octanol-water partition coefficient. Techniques used for cleanup of SPMD extracts for targeted analytes and for general screening by full-scan mass spectrometry do not differ greatly from techniques used for extracts of other matrices. However, SPMD extracts contain potential interferences that are specific to the membrane-lipid matrix. Procedures have been developed or modified to alleviate these potential interferences. The SPMD approach has been demonstrated to be applicable to sequestering and analyzing a wide array of environmental contaminants including organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polychlorinated dioxins and dibenzofurans, selected organophosphate pesticides and pyrethroid insecticides, and other nonpolar organic chemicals. We present herein an overview of effective procedural steps for analyzing exposed SPMDs for trace to ultra-trace levels of contaminants sequestered from environmental matrices.

Selective removal of organic contaminants from sediments: a methodology for toxicity identification evaluations (TIEs).

Aqueous slurries of a test sediment spiked with dibenz[a,h]anthracene, 2,4,5,2',4',5'-hexachlorobiphenyl, p,p'-DDE, or phenanthrene were subjected to decontamination experimentation. The spiked sediments were agitated at elevated temperatures for at least 96 h in the presence of either of the two contaminant-absorbing media: clusters of polyethylene membrane or lipid-containing semipermeable membrane devices (SPMDs). The effects of treatment temperature and surface area of media on the removal of contaminants were explored. This work is part of a larger methodology for whole-sediment toxicity identification evaluation (TIE). A method is being sought that is capable of detoxifying sediments with respect to organic contaminants while leaving toxicity attributable to inorganic contaminants unaffected.

Aquatic hazard assessment of the organophosphate insecticide fonofos.

This study determined the acute and chronic toxicity of the organophosphate insecticide fonofos to standard freshwater aquatic organisms under laboratory conditions. Fonofos was acutely toxic to bluegill (Lepomis macrochirus), Daphnia (D. magna), and midge (Chironomous riparius) at 5.3, 2.7, and 39 micrograms/L, respectively. Three fonofos formulations (technical, 94.8% A.I.; 20G, field granular 20% A.I.; and 4E, field liquid 4#/gal A.I.) exhibited similar acute toxicities to bluegill. Exposure to fonofos delayed reproduction and decreased the intrinsic rate of increase of Daphnia during 21-d chronic exposure at the lowest tested concentration (0.08 micrograms/L). The no observable effect concentration (NOEC) for Daphnia survival was 0.42 micrograms/L; 0% survival occurred at the lowest observable effect concentration (LOEC) of 1.45 micrograms/L. The NOEC for midge emergence was 3.42 micrograms/L; only 34% emergence occurred at the LOEC of 8.24 micrograms/L. Chronic 30-d exposure of juvenile bluegills decreased growth and survival at 5.65 micrograms/L (LOEC), but no effects occurred at 2.33 micrograms/L (NOEC). The relative hazard of fonofos to aquatic life is similar to other carbamate and organophosphate corn insecticides.

Role of exposure mode in the bioavailability of triphenyl phosphate to aquatic organisms.

A laboratory study was conducted to investigate the role of the route of triphenyl phosphate (TPP) entry on its aquatic bioavailability and acute biological effects. Three TPP treatments were used for exposures of fish and invertebrates. These consisted of TPP dosed directly into water with and without clean sediment and TPP spiked onto sediment prior to aqueous exposures. Results of static acute toxicity tests (no sediment) were 0.78 mg/L (96-h LC50) for bluegill, 0.36 mg/L (48-h EC50) for midge, and 0.25 mg/L (96-h EC50) for scud. At 24 h, the sediment (1.1% organic carbon)/water partition coefficient (Kp) for TPP was 112. Use of this partition coefficient model to predict the sediment-mediated reduction of TPP concentration in water during toxicity tests resulted in a value that was only 10% less than the nominal value. However, the required nominal concentration of TPP to cause acute toxicity responses in test organisms was significantly higher than the predicted value by the model for both clay and soil-derived sediment. Direct spiking of TPP to soil minimized TPP bioavailability. Data from parallel experiments designed to track TPP residues in water through time suggest that sorption kinetics control residue bioavailability in the initial 24 h of exposure and may account for observed differences in LC50 and EC50 values from the sediment treatments.

Distribution and bioaccumulation of selenium in aquatic microcosms.

Closed-system microcosms were used to study factors affecting the fate of selenium (Se) in aquatic systems. Distribution and bioaccumulation of Se varied among sediment types and Se species. A mixture of dissolved (75)Se species (selenate, selenite and selenomethionine) was sorbed more rapidly to fine-textured, highly organic pond sediments than to sandy riverine sediments. Sulfate did not affect the distribution and bioaccumulation of (75)Se over the range 80-180 mg SO(4) liter(-1). When each Se species was labeled separately, selenomethionine was lost from the water column more rapidly than selenate or selenite. Selenium lost from the water column accumulated primarily in sediments, but volatilization was also an important pathway for loss of Se added as selenomethionine. Loss rates of dissolved Se residues were more rapid than rates reported from mesocosm and field studies, suggesting that sediment: water interactions are more important in microcosms than in larger test systems. Daphnids accumulated highest concentrations of Se, followed by periphyton and macrophytes. Selenium added as selenomethionine was bioaccumulated preferentially compared to that added as selenite or selenate. Organoselenium compounds such as selenomethione may thus contribute disproportionately to Se bioaccumulation and toxicity in aquatic organisms.

Structure-activity relationships of chlorinated benzenes as inducers of different forms of cytochrome P-450 in rat liver.

Hexachlorobenzene (HCB) produced increases in ethoxyresorufin (ERR) O-deethylase, aryl hydrocarbon hydroxylase (AHH) and aminopyrine N-demethylase activities in rat liver phenobarbital which were intermediate between those produced by phenobarbital and 3,4-benzpyrene (BP), alpha-Naphthoflavone (ANF) selectivity inhibited ERR activity in BP and HCB-induced microsomes (94% and 88%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of liver microsomes indicated that HCB did not produce a detectable increase in a polypeptide with electrophoretic properties similar to those of purified cytochrome P-448 (Mr = 56,000). However, HCB did induce a polypeptide with Mr = 53,000 corresponding to one of two polypeptide bands induced by BP. This polypeptide may represent a second form of cytochrome P-448. Purification of HCB to remove possible dibenzo-p-dioxin impurities did not alter the 'mixed-type' induction produced by HCB. In contrast to HCB, all other chlorinated benzenes tested resembled phenobarbital as inducers.

Biological effects of kepone and mirex in freshwater invertebrates.

Acute and chronic toxicity studies of Kepone (chlordecone) and mirex were conducted with daphnids (Daphnia magna), amphipods (Gammarus pseudolimnaeus), and larvae of a midge (Chironomus plumosus). Acute toxicities of Kepone ranged from a 48-hr EC50 of 350 microgram/L for midges to a 96-hr LC50 of 180 microgram/L for amphipods, whereas the acute toxicities of mirex to all three taxa exceeded 1000 microgram/L. Maximum acceptable toxicant concentrations (MATC's) for Kepone and mirex were estimated by measuring reproduction of daphnids, growth of amphipods, emergence of midges, and survival of all organisms. MATC for Kepone was estimated to be between 9 and 18 microgram/L for daphnids, between 1 and 2 microgram/L for amphipods, and between 8.4 and 18 microgram/L for midges; MATC for mirex exceeded 34 microgram/L for daphnids and midges, but less than 2.4 microgram/L for amphipods. The concentration of Kepone and mirex accumulated by daphnids was 760 and 8025 times, respectively, the concentration in water. Estimated times for elimination of 50% of the residues by daphnids were 141 hr for Kepone and 12 hr for mirex.