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Professional training development, whether for a classroom, work environment, or other setting, typically follows a validated instructional design model that includes an assessment of learner needs before the development of a training. This foundational principle is integrated into federal guidance documents for emergency preparedness training. That said, local preparedness resources are sometimes in misalignment with this principle. Funding tends to favor nationally defined priorities as a proxy for the assessment of local needs. This letter explores this dynamic in the context of the response to Superstorm Sandy, and proposes a revised funding paradigm to support training development.

Adsorption of hydrophobic organic contaminants (HOCs) to black carbon is a well-studied phenomenon. One emerging class of engineered black carbon materials are single-walled carbon nanotubes (SWNTs). Little research has investigated the potential of SWNT to adsorb and sequester HOCs in complex environmental systems. This study addressed the capacity of SWNT, amended to polychlorinated biphenyl (PCB)-contaminated New Bedford Harbor (NBH) sediment, to reduce the toxicity and bioaccumulation of these HOCs to benthic organisms. Overall, SWNT amendments increased the survival of two benthic estuarine invertebrates, Americamysis bahia and Ampelisca abdita, and reduced the accumulation of PCBs to the benthic polychaete, Nereis virens. Reduction in PCB bioaccumulation by SWNT was independent of Kow. Further, passive sampling-based estimates of interstitial water concentrations indicated that SWNT reduced PCB bioavailability. Results from this study suggest that SWNT are a good adsorbent for PCBs and might be useful for remediation in the future once SWNT manufacturing technology improves and costs decrease.

Silver nanomaterials are the major components of healthcare products largely because of their antimicrobial effects. However, their unintended toxicity to biological organisms and its mechanism are not well understood. Using medaka fish embryo model, the toxic effects and corresponding mechanisms of silver nanocolloids (SNC, particle size 3.8 ± 1.0-diameter nm) were investigated. SNC caused morphological changes in embryos including cardiovascular malformations, ischemia, underdeveloped central nervous system and eyes, and kyphosis at exposures of 0.5 mg/L. Interestingly, SNC were observed inside the eggs at a level of 786.1 ± 32.5 pg/mg egg weight, and TEM analysis showed that SNC adhered to the surface and inside of the chorion. Meanwhile, medaka oligo DNA microarray and qRT-PCR were used for gene expression analysis in the embryos exposed to 0.05 mg/L SNC for 48 h. As a result, expressions of six of the oxidative stress-, embryogenesis- and morphogenesis-related genes, ctsL, tpm1, rbp, mt, atp2a1, and hox6b6, were affected by the SNC exposure, and these genes' involvement in those malformations was implied. Thus, SNC could potentially cause malformations in the cardiovascular and central nervous systems in developing medaka embryo through SNC-induced differential expression of the genes related to oxidative stress, embryonic cellular proliferation, and morphological development.

The marine copepod, Amphiascus tenuiremis (A. tenuiremis), is a well characterized invertebrate model for the screening and evaluation of endocrine and reproductive toxins using life-cycle assays. These tests evaluate phenotypic endpoints related to development and reproduction, which are utilized to predict population outcomes. Some of these endpoints in arthropods, including sexual maturation and molting, are controlled by the hormone ecdysone which acts through its cognate receptor, the ecdysone receptor. The purpose of this research was to obtain and characterize sequence information for the A. tenuiremis ecdysone receptor and investigate modulation of expression levels by fipronil, an insecticide that causes infertility in males and reduced egg extrusion in female copepods, and ponasterone, a natural ecdysone receptor agonist. Results show successful cloning and phylogenetic analysis of the ecdysone receptor for A. tenuiremis, providing the first genetic information for a hormone receptor in this species. Exposure of copepodites to fipronil for 1, 2, 4, 18 and 30 h caused a significant increase in ecdysone receptor transcriptional expression at 30 h compared to control unexposed animals. This work illustrates a potential mechanism whereby exposure to fipronil, and potentially other endocrine disrupting compounds, results in impacted reproduction. Furthermore, this exemplifies the potential utility of ecdysone receptor transcriptional measurement as a sensitive and rapid biomarker of ecological relevance when linked to traditional A. tenuiremis bioassays.

This article presents the development of a program and results of a study to evaluate an online distancebased learning (DBL) program for competency-based, basic emergency preparedness training for employees of local health departments nationwide. The program was developed and implemented beginning in May 2003 by Columbia University’s Center for Public Health Preparedness (CU-CPHP), and was designed to be delivered in two parts. The first part was an online training program, providing the basic knowledge required for public health preparedness. The second part was a downloadable template, which the student could use to guide learning and subsequent demonstration of the core emergency preparedness competencies to his or her supervisor. The student could return this documentation to the CU-CPHP to receive a certificate of completion, which would be e-mailed to the recipient. Evaluation findings indicate that this course resulted in a high degree of participant satisfaction along with an increased level of participant understanding of the basic emergency preparedness core competencies.

Several of the most disconcerting and compelling news events of the 21st century pertain to natural and human-caused disasters. However, these themes are generally absent in the social studies, civics, science, or mathematics curricula of most U.S. K-12 schools. Similarly, discussions about ways to incorporate new digital tools, such as mobile tablet computers and apps into such discussions are also overlooked. This chapter provides a roadmap for considering disaster-oriented themes in the K-12 curriculum and then provides several examples of apps that can be included in classroom lessons along with guidelines for incorporating these digital tools into pedagogical practices. The authors have framed their analysis within the context of mLearning as a way to address cross-disciplinary themes via mobile technologies.

Acute toxicities of crude oil and crude oil water accommodated hydrocarbon fraction (WAF) are relatively well documented, but data on the biological effects of chronic exposures to WAF on species and populations are scarce. South Louisiana Sweet crude oil was used to assess the effects of crude oil WAF on the copepod Amphiascus tenuiremis’ survival, development and reproduction. Effects were evaluated using a 96-well microplate full life-cycle toxicity test, a test that allows tracking of individuals from the nauplius stage to sexual maturation and reproduction. Briefly, 24-h hatched nauplii were followed to adulthood (ni=z120 nauplii/treatment) in individual glass-coated microplate wells containing 200 AL of seawater solution. Treatments consisted of 10%, 30%, 50% and 100% Louisiana WAF, with seawater used as control. Nauplii were monitored through development to adulthood, and sexually mature virgin copepods were mated pairwise in wells containing original rearing treatments. Nauplius-tocopepodite survival was reduced by 57% in exposures to 100% WAF, relative to controls (88F3%), and copepodite-to-adult survival was reduced by 18% in the 50% WAF, relative to controls (98F3%). Analysis of development curves showed that nauplii in the 10% WAF developed significantly faster into copepodites, while nauplii in the 50% WAF developed significantly slower than controls. Although the naupliar developmental rate in the 100% WAF was not significantly different from the control, these nauplii showed an average 1.4 day delay in development into copepodites. Similarly, copepodite development into mature females and males was significantly enhanced by 1.2 to 1.8 days and delayed by 1.9 to 2.2 days (pb0.05) in the 10% and 50% WAFs, respectively, compared to controls. Although the copepodite developmental rate in the 100% WAF was not significantly different from the control, these copepodites still showed an average 1.5 and 2.1 day delay in development into females and males, respectively. Analysis of reproductive endpoints showed that fertility was the only endpoint negatively affected by WAFs; reproductive failure increased by 30% and 41% in exposures to 30% and 100% WAF, respectively, compared to controls (3.33F4.71%). Leslie matrix population projections based on empirical microplate data indicated lower production rates through three generations of exposure to WAFs. Furthermore, a comparison between NIST and Louisiana crude oil WAFs using the same life-cycle approach indicated a greater chronic toxicity for the Louisiana WAF and an overall developmental delay in exposures to high WAFs (50% and 100% WAFs) from both crude oil types. D 2005 Elsevier B.V. All rights reserved.

Trace/minor element signatures ( D Cd , D Ba , D Mg , and D Sr ) were measured in the tests (shells) of benthic foraminifera cultured in a trace-metal-concentration-controlled system. The culture system was constructed of inert materials and designed to limit microhabitat effects. This system ensured that variation observed in cultured foraminiferal element:calcium (TE/Ca) signatures was due to biologically mediated (vital) effects only. Two species, Bulimina aculeata and Rosalina vilardeboana , reproduced prolifically during two 4-to-8-month culture periods. In every case (i.e., for both species and each element), the inter-individual variability was larger than the analytical precision. Mean (±1 standard deviation) D E signatures for B. aculeata were: D Cd : 1.5 ± 0.4, D Ba × 10: 2.1 ± 0.7, D Mg × 1000: 0.62 ± 0.15, and D Sr × 10: 1.5 ± 0.1. Cultured B. aculeata D Mg , calibrated from culture and core-top (live) field specimens, predicted temperatures within ±2.0 °C. The observed inter-individual variability from culture specimens was as large or larger than comparable results from core-top investigations. R. vilardeboana D Cd signatures were significantly lower, while D Ba , D Mg , and D Sr signatures were significantly higher than B. aculeata values. Since our culture system minimizes microhabitat variability, the variation in measured TE/Ca ratios suggests that biological processes are a significant factor in inter-individual and inter-species variability. Comparison of cultured and field-collected foraminiferal D Ba signatures supports previous findings that pore-water chemistry is a major environmental influence on foraminiferal test chemistry.

Ontogenetic (developmental stage) measurements of Mg/Ca and Sr/Ca were made on the benthic foraminifer Bulimina aculeata , which were cultured under controlled physicochemical conditions of temperature, pH, alkalinity, salinity, and trace- and minor-element concentrations. We utilized two methods of ontogenetic sampling—whole specimens progressively increasing in length and laser microdissection of a single specimen with subsequent analysis of dissected portions. A novel high-resolution laser-microdissection (HRLM) method allowed for precise (10 μm) cuts of the foraminiferal tests (shells) along the geometrically complex sutures distinguishing individual chambers. This new microdissection method limited sample loss and cross-contamination between foraminiferal chambers. Little or no variation in D Sr was observed at different foraminiferal developmental stages. Conversely, D Mg was enriched during a mid-developmental stage of whole-specimen samples (150–225 μm D Mg = 1.6 × 10 −3 ) compared to earlier and later stages ( 225 μm D Mg = 8.3 × 10 −4 ). Further analysis of HRLM ontogenetic samples showed a larger, age-dependent D Mg signature variation. This increase in shell Mg/Ca may contribute substantially to the measured inter-individual variability in Mg/Ca temperature prediction for cultured B. aculeata . Due to relatively large Mg/Ca inter- and intra-individual variability, measuring similar-size foraminiferal samples may improve the precision of paleotemperature prediction. Additionally, partial dissolution of the highest ontogenetically Mg-enriched calcite ( D Mg = 1.3 × 10 −2 –1.6 × 10 −2 ) may occur in undersaturated bottom-water environments or during reductive cleaning procedures. Thus, the calcite phases remaining after partial dissolution by either natural or laboratory cleaning processes may not accurately represent the calcification environment.

Atrazine is a widely used herbicide in the US found at levels ranging from10 ng/L to 62.5 microg/L in estuaries throughout the southeast. Effects of atrazine on estuarine meiobenthic assemblages chronically exposed to environmentally relevant concentrations are unknown. The purpose of our research was to assess effects of atrazine on meiobenthos at concentrations near the proposed USEPA SWQC (26 microg/L) using modular estuarine salt marsh mesocosms as a field surrogate. Indigenous copepod and nematode densities were assessed after 28 days of exposure in transplanted colonization chambers. Cluster analysis showed a group characterized by low copepod densities, mostly atrazine exposed chambers, and a group containing all but one control chamber. The later group included chambers with high densities of the copepods Paronychocamptus wilsoni and Enhydrosoma baruchi. Compared to controls, copepod densities was approximately 70% lower in atrazine chambers, with three of the most common copepod species (E. baruchi, Onychocamptus sp. and P. wilsoni) showing an average of 50-70% reduction in population densities (p0.05). Although nematode density did not differ between atrazine and control chambers, the nematode-to-copepod ratio was significantly higher in atrazine (9.95+/-7.61; p=0.011) than in control chambers (0.61+/-0.35). Our findings suggest that chronic exposures over multiple generations to atrazine at concentrations near the proposed USEPA SWQC could have significant effects on the abundance and composition of estuarine meiobenthic copepod assemblages.

Dissolved organic matter (DOM) is comprised of a myriad of macromolecules with specific physical and chemical properties that may influence the bioavailability of hydrophobic pesticides to animals. This study was conducted to assess the role of various forms of DOM on the uptake and bioconcentration of the organophosphate insecticide chlorpyrifos (CHPY) to the bivalve Mercenaria mercenaria. Bivalves were exposed to DOM-free seawater (30 per thousand) or to seawater containing a single form of DOM. DOM forms included two filtrate fractions of natural salt-marsh sediment DOM (DOM-(0.45 mum) and DOM-(3 kDa)); natural purified humic (HA) and fulvic (FA) acids; and water soluble cyclic oligosaccharides alpha and beta cyclodextrins (CD-alpha and CD-beta). In (14)C-CHPY uptake and elimination experiments, juvenile bivalves were exposed to uniformly-labeled (14)C-CHPY and collected at time intervals during 48 h. The remaining bivalves were transferred to (14)C-CHPY-free elimination chambers with bivalve collection at time intervals over 144 h. Total uptake of (14)C-CHPY by bivalves in DOM-free seawater was40% greater than in bivalves exposed to (14)C-CHPY in the presence of most DOM forms. These results are consistent with much faster (14)C-CHPY uptake rates estimated using a simple two parameter model. After the elimination period, bivalves exposed to DOM-free seawater had (14)C-CHPY body residue concentrations between 25% and 86% greater than bivalves in the presence of DOM forms. Experiments with larger bivalves showed that pulse-chase exposures with a 1.5 h exposure period to (14)C-CHPY was not long enough to detect differences in (14)C-CHPY tissue accumulation efficiencies across treatments. Our findings suggest that natural forms of DOM, at environmentally realistic organic carbon concentrations, reduced pesticide uptake and bioconcentration, consistent with much lower uptake rates relative to bivalves exposed to (14)C-CHPY in the absence of DOM. Interestingly, at the tested organic carbon concentrations CD-alpha and CD-beta did not reduce (14)C-CHPY bioconcentration in M. mercenaria.

Dissolved organic matter (DOM) represents an important carbon phase in coastal environments and influences the partitioning of organic contaminants. In this study, we evaluated the role of salt-marsh sediment-derived DOM vs. DOM-free seawater on the acute and chronic toxicity of three pesticides (chlorothalonil—CHTH, chlorpyrifos—CHPYand fipronil—FIP) to the meiobenthic copepod Amphiascus tenuiremis. Acute toxicity was evaluated via standard 96-h median lethal concentration (LC50), while chronic toxicity was evaluated for 16 days using a 96-well microplate life-cycle bioassay. DOM significantly reduced (pb0.05) acute toxicity of CHTH and CHPY to male and female copepods relative to copepods exposed in DOM-free seawater. In contrast, DOM elevated the acute toxicity of FIP to male copepods. In chronic exposures with/without DOM, CHTH and CHPY did not significantly affect copepodite-to-adult development. In these treatments, plus controls, the majority (95%) of copepodites developed into adults by 8 days. Individuals exposed to FIP in the presence of DOM showed a slower development rate than FIP individuals in DOM-free seawater. Overall, FIP exposed copepodites developed into adult copepods 4 days later than controls. CHTH, CHPY and FIP significantly reduced reproductive success by 33%, 31% and 89%, respectively. DOM, however, mitigated 30% (p=0.006) and 20% (p=0.05) of the reproductive failure attributed to CHTH and CHPY. FIP-induced reproductive failure was high (~80%) in all exposures regardless of DOM presence/absence. An exponential growth model predicted that exposure to CHTH, CHPY and FIP in the absence of DOM significantly reduced (z38%) projected naupliar production relative to DOM-free controls. In the presence of DOM, naupliar production under CHTH and CHPYexposures was not significantly different (pN0.05) from control projections. These results indicate that DOM generally reduced the acute and chronic toxicity of CHTH and CHPY to A. tenuiremis, while certain compound-specific pesticide (FIP): organic associations may enhance acute toxicity of FIP, particularly to male copepods. D 2005 Elsevier B.V. All rights reserved.

The predominant data used in ecological risk assessment today are individual-based rather than population-based; yet environmental policies are usually designed to protect populations of threatened species or communities. Most current methods in ecotoxicology are limited by largely logistic/ technology-driven requirements that yield data for a relatively small number of test species and end points that focus on acute lethality or sublethal nonproduction-based parameters (e.g., biomarkers, mutagenesis, genetic change, physiological condition). A contrasting example is presented here showing the predictive ability of meiobenthos-based full life cycle toxicity testing to extrapolate multi-generational effects of chemicals on variables of import to population growth and maintenance. Less than 24-h-old larvae of a meiobenthic copepod were reared individually in 96-well microplate exposures to parent and degradates of the phenylpyrazole insecticide fipronil. Survival, development rates, sex ratio change, fertility, fecundity, and hatching success were tracked daily for 32 d through mating and production of three broods in spiked seawater. These data were then inserted in a Leslie (Lefkovitch) matrix stage-based population growth model to predict relative rates of population increase (lambda) and changes in net population growth with time and toxicant concentration. Field-reported test concentrations produced strong reproductive (52-88%) and net production (40-80%) depressions for parent (at 0.25 and 0.5 microg/L), desthionyl (0.25 and 0.5 microg/L), and sulfide (0.15 microg/L) moieties as compared to controls. Spiked sediment exposures of 65-300 ng of fipronil/g of dry sediment yielded significantly reduced production rates per female that were 67-50% of control production. The consistent reproductively linked impacts of fipronil and its degradation products at the population maintenance levels suggest risks to sediment-dwelling crustaceans at concentrations well below noneffects for most aquatic test species based on risk assessment data from primarily acute and sub-life cycle toxicity tests.

Coastal urbanization supplies surrounding estuarine environments with urban-related contaminants such as polycyclic aromatic hydrocarbons (PAHs), metals and pesticide mixtures. In our study, adult female and male copepods (Amphiascus tenuiremis) were chronically exposed to 18 sediment samples collected from sites influenced by different land-uses. Sediment samples were collected from three major suburban areas (Hilton Head, Kiawah Island and the Okatee River watershed) and a pristine site (North Inlet) in coastal South Carolina. Three-sediment bioassays (six sites per bioassay) were conducted by culturing copepods for 14 days in quadruplicate test sediments under flow-through conditions at 20 � C and 12:12 LD cycles. Adult survival and copepod reproductive output were quantified. Sediment samples were also analyzed by GC–MS for low and high molecular weight PAHs. Minimal adult mortality was observed in most sediment samples. However, sediments from Hilton Head Island and the Okatee River showed significant effects on copepod reproductive output (i.e., nauplii, copepodites and clutch size). Thus, we determined that reproductive endpoints rather than adult copepod survivorship were more sensitive to effects of contaminated sediments on A. tenuiremis. Furthermore, six (33%) of the 18 sites had a >25% reduction in copepod bioassay endpoints relative to controls, suggesting a high risk to long term A. tenuiremis population maintenance. � 2004 Elsevier Ltd. All rights reserved.

We present an apparatus and procedure for culturing deep-sea (i.e., bathyal) benthic foraminifera under physicochemically constrained conditions. A 1600-L recirculating culture system was constructed to contribute negligible trace metal contamination; the system was housed in an environmental room maintained near in situ temperatures but at atmospheric pressure. Peristaltic pumps continuously circulated 3 mL seawater min−1 from the reservoir to 9 to 12 culture chambers. A 2-mm-thick layer of high-purity clay-sized silica substrate was used to minimize the impact of sedimentary microhabitats. Physicochemical parameters (salinity, alkalinity, pH, temperature) varied 200 d in each experiment and produced up to 2,800 individuals per culture. The growth and reproduction of benthic foraminifera in a physicochemically constrained culture provide a new method for the experimentation and validation of geochemical proxies.

We describe a novel application of the fluorescent compound calcein (Bis[N,N-bis(carboxymethyl)aminomethyl]-fluorescein), which was used to fluorescently label foraminiferal calcite. Foraminifers that were incubated in a 10 mg L−1 solution of calcein and seawater precipitated normal-looking chambers during and after calcein incubation, which lasted up to three weeks. The survival rate of specimens incubated in calcein was similar to that of control specimens; some specimens reproduced during or after calcein exposure. Thus, this calcein-tagging method is non-lethal. Chambers precipitated during calcein incubation fluoresced a yellow-green when viewed with epifluorescence or laser scanning confocal microscopy (470 nm excitation, 500 nm emission). When viewed alternatively with reflected light, chambers formed after calcein incubation were easily distinguished from calcein-marked chambers, because calcite precipitated after calcein exposure does not fluoresce. Fluorescence is retained through fixation and air drying, thus the signal can be viewed in archived specimens. The method was executed on specimens from 15 species collected from three habitats with diferent environmental conditions. Results indicate that calcein is incorporated by all 15 species. The method has a number of potential applications, including experiments aimed at identifying benthic foraminifers that are faithful recorders of paleoceanographic proxies, as well as field studies to assess locations and chronology of foraminiferal calcification.

Although much is known regarding photoperiodic effects on crustacean egg production, the effects of ultraviolet (UV) light on reproduction has not been investigated. Likewise, little is known concerning the interaction between UV and xenobiotic exposure on crustacean reproductive cycles. In this study, male and female grass shrimp, Palaemonetes pugio, were exposed to sublethal concentrations of endosulfan (200 ng/l and 400 ng/l ES) under both white fluorescent (WF) and UV-A (315-400 nm) light conditions for 50 days in laboratory bioassays. Female endocrine (vitellogenin, ecdysteroids, and cholesterol), reproductive (percent gravid, clutch size), and embryo (days to hatch, hatching success, and hatching survival) responses were assessed. UV-exposure alone caused a significant (>4-fold) increase in total Palaemonetes pugio female egg production over the course of 50 days. Exposure to ES and UV significantly lowered the percentage of gravid females relative to UV controls, whereas ES-exposed shrimp under WF lighting did not exhibit these trends. Although higher vitellogenin concentrations and lower ecdysteroid titers were correlated with increased female egg production, cholesterol titers only exhibited a dose-dependent change when exposed to ES. Embryos from females exposed to UV had significantly lower ecdysteroid titers and shorter hatching times but there were no differences in embryo vitellogenin concentrations, hatching success, or hatching survival. These results indicate that UV-A exposure has a pronounced effect on grass shrimp (Palaemonetes pugio) reproduction and is likely mediated through 5-hydroxytrptamine (5-HT)-related neuroendocrine pathways. The implications for decapod aquaculture and evaluating chronic contaminant effects are discussed.

†University of South Carolina, Norman J. Arnold School of Public Health, Department of Environmental Health Sciences, Columbia,South Carolina, USA 29208‡State University of New York–Stony Brook, Marine Sciences Research Center, Stony Brook, New York, USA 11794(Received 10 September 2001; Accepted 11 April 2002)Abstract—Microtechniques for polycyclic aromatic hydrocarbon (PAH) body burden and total lipid analysis were developed andapplied to determine the first lipid-normalized bioaccumulation factors for a hydrophobic organic toxicant in a meiobenthicorganism(0.063–0.500 mm) living in field-contaminated sediments. The total lipid microtechnique combines the standard Bligh–Dyer ex-traction method with a colorimetric quantification method for analysis of samples containing 1 to 50mg lipid. The microtechniquefor body burden analysis quantifies PAHs from tissue samples containing as little as 10 pg PAH. Fluoranthene, benz[a]anthracene,and benzo[a]pyrene biota-sediment accumulation factors (BSAFs) were determined for the meiobenthic copepodMicroarthridionlittorale living in an estuarine U.S. Environmental Protection Agency Superfund site. Gravid female, nongravid female, and maleBSAFs were 0.82, 0.54, and 0.36, respectively, for fluoranthene; 0.50, 0.44, and 0.40, respectively, for benz[a]anthracene; and0.09, 0.12, and 0.15, respectively, for benzo[a]pyrene. Comparison of nonlipid-normalized bioaccumulation factors (BAFs) toBSAFs indicates that M. littorale bioaccumulated PAHs on a gram lipid basis. The BSAFs declined consistently with increasingPAH log K

The harpacticoid copepod Microarthridion littorale (Poppe) was tested for interaction effects between salinity change and acute pesticide exposure on the survival and genotypic composition of a South Carolina population. Previous data suggested a significant link between a combined exposure to chlorpyrifos (CHPY) and dichloro-diphenyl-trichloroethane (DDT) and mitochondrial haplotype in the cytochrome b apoenzyme for this euryhaline species when exposed at 12-ppt salinity seawater. Our tests demonstrate a significant non-linear survival response for M. littorale to short-term immersion (24 h) in 3-, 12- and 35-ppt seawater, with copepods transferred to 12-ppt seawater having the lowest survival. There was significant statistical interaction between salinity and pesticide exposure for the dependent variable “survival.” However, changes in genetic composition of survivors were not significant, and they were complicated by extremely low survival in the pesticide/3 ppt and pesticide/36 ppt treatments. As noted for many studies of harpacticoids, males faired worse than females in all treatments, with none surviving pesticide exposure at 45 μg/l CHPY and 6 μg/l DDT.

Little is known about environmental biodegradability or biotransformations of single-walled carbon nanotubes (SWNT). Because of their strong association with aquatic organic matter, detailed knowledge of the ultimate fate and persistence of SWNT requires investigation of possible biotransformations (i.e., biodegradation) in environmental media. In the present study, [(14)C]SWNT were utilized to track biodegradation over 6 mo by pure liquid culture of the fungus Trametes versicolor and mixed bacterial isolates from field-collected sediment or aerated wastewater treatment plant sludge. The mixed cultures were chosen as more environmentally relevant media where SWNT will likely be deposited under both aerobic and anaerobic conditions. Activity of [(14)C] was assessed in solid, aqueous, and (14)CO2 gaseous phases to determine amounts of intact SWNT, partially soluble SWNT degradation products, and mineralized SWNT, respectively, during the 6 mo of the experiment. Mass balances based on radiocarbon activity were approximately 100% over 6 mo, and no significant degradation of SWNT was observed. Approximately 99% of the [(14)C] activity remained in the solid phase, 0.8% in the aqueous phase, and less than 0.1% was mineralized to (14)CO2, regardless of culture type. These results suggest that SWNT are not readily biodegraded by pure fungal cultures or environmental microbial communities, and are likely persistent in environmental media.

Systems thinking provides a powerful cognitive and pedagogical tool for considering problems related to sustainability. This chapter pays particular attention to critical conceptual aspects of systems thinking as manifest in the use of a curriculum guide addressing Hurricane Katrina called Teaching the Levees: A Curriculum for Democratic Dialogue and Civic Engagement. The three educators in this study used the Teaching the Levees curriculum guide in order to focus on a specific disciplinary aspect of social studies education. The educators also integrated a variety of social, ecological, economic, and political issues in their lessons. The inclusion of these disciplines supports the perspective that the educators were engaged in systems thinking, particularly in how they conceived of the patterns in which events emerged, the interconnectedness of discrete elements, and the impact of feedback loops within the system. The chapter also addresses ramifications of systems thinking within social studies education.

We present the first trace metal partition coefficients obtained from reproducing cultures of deep-sea benthic foraminifera. Paleoceanographically important species, including juvenile Bulimina marginata , Cibicidoides pachyderma , and Uvigerina peregrina , were maintained in sediment microcosms at 10°C, 35 psu, and pH 8 for 1–3 years. Juvenile foraminifera were separated, cleaned, and dissolved under clean conditions for determination of trace metal partition coefficients on recently deposited (1–3 months) foraminiferal calcite. In addition to the deep-sea species, we analyzed a shallow water benthic foraminifer, Ammonia beccarii . Overlying water samples were collected from the microcosms concurrent to the period of calcification (3 months prior to separation). Ba/Ca partition coefficients ( D Ba ) were measured in replicate for benthic foraminifera species Bulimina marginata (0.24 ± 0.07), Uvigerina peregrina (0.24 ± 0.06, Ammonia beccarii (0.20 ± 0.04). The D Ba for Bulimina marginata and Uvigerina peregrina were found to closely match the range from the Ontong Java Plateau. Sample size limitations allowed for only one analysis of D Ba for Cibicidoides pachyderma . However, our nonreplicated D Ba of 0.5 ± 0.1 falls within the accepted range of core top samples (0.37 ± 0.06). We report a D Cd for Ammonia of 1.0 ± 0.5, for Cibicidoides of 4 ± 2, for Bulimina of 3 ± 1, and for Uvigerina 2 ± 1 which all fall within the ranges reported for core top calibrations. The large uncertainties in D Cd reflect variation in dissolved Cd concentration in the artificial seawater reservoir due to loss and replacement of Cd during the course of the experiment. The variability between species is probably the result of variability in pore water Cd in the sediment culture system and may reflect habitat effects.

In chronic bioassays of sediment organic compounds, toxicant exposures often decline through time, such that the beginning of a test yields disproportionately higher exposures than the end. Thus, those life stages initiating a test often are exposed to the highest concentrations, and for rapidly maturing test fauna, this may lead to varying conclusions regarding compound toxicities depending on the initial life stage chosen. This problem can be addressed by comparative full life-cycle tests initiated with different test-organism life stages. Thus, a full life stage-to-life stage toxicity test was developed for the rapidly maturing meiobenthic copepod Amphiascus tenuiremis to assess the importance of developmental stage at the onset of sediment toxicant exposure relative to reproduction, net population growth, and sex and age structure. Tests were conducted with a model spiked-sediment insecticide, chlorpyrifos, for each of the major life stages (P1) of A. tenuiremis (nauplius, copepodite, and adult). Each P1 stage was allowed to mature and reproduce in low chlorpyrifos concentrations (6–33% of stage-specific 96-h LC50s; 4–22 ng chlorpyrifos/g dry sediment) for 26 d. Test endpoints were numbers of surviving adult females, males, eggs per female (clutch), first generation (F1) nauplii, F1 copepodites, F1 total production, and realized F1 production per surviving female. Only the copepodite P1 test showed a significant decline in survival of an adult age class: females declined by 28% at 22 ng/g. Reductions in total production ranged from 33–96% of controls from nauplius to adult. The P1 naupliar stage was most sensitive, with F1 production being 33–47% of that in controls. However, on a realized production per female basis, both the copepodite and naupliar P1 yielded significantly reduced F1S of 23 and 40% of controls at 11 and 22 ng/g.

Meiobenthic copepod populations ( Microarthridion littorale) were collected from three South Carolina, USA, estuaries having different pollution stress histories (i.e., pristine sediments, high polycyclic aromatic hydrocarbon (PAH) sediments, high metals/moderate PAH sediments) and then assayed for survival and reproductive output in 14-d exposures to pristine and heavily PAH/metals-contaminated sediments. Whole-sediment reproduction bioassays were used to determine whether copepods exposed to a highly contaminated sediment mixture exhibited differential survival and reproductive outputs as a function of previous environmental histories and whether genetic relatedness among populations measured as DNA sequences of the mitochondrial gene, cytochrome apoenzyme b, were linked to copepod contaminant tolerance. Overall, adult survival and reproductive success in contaminated sediments were significantly reduced relative to controls for all three populations irrespective of environmental histories. Differential resistance to sediment-contaminant mixtures by the two copepod populations inhabiting the contaminated sites was not found, despite their previous exposures to mixed contaminants at SPAH and SMetal concentrations of 7,287 to 2,467 ng/g dry wt and 461 to 3,497 mg/g, respectively. Significant genetic differentiation, however, was found between copepod populations from the control and the two contaminated sites. Generally, cross-population survival and reproductive outputs were not significantly different and could not be linked to genetic differentiation at the population level.

We conducted experiments to determine effects of particle type on assimilatory metal bioavailability to Leptocheirus plumulosus,an infaunal, estuarine amphipod that is commonly used in sediment toxicity tests. The following particles were used to represent natural food items encountered by this surface-deposit and suspension-feeding amphipod: bacterial exopolymeric sediment coatings, polymeric coatings made from Spartina alterniflora extract, amorphous iron oxide coatings, the diatom Phaeodactylum tricornutum, the chlorophyte Dunaliella tertiolecta, processed estuarine sediment, and fresh estuarine sediment. Bioavailability of the gamma-emitting radioisotopes 110m Ag, 109 Cd, and 65 Zn was measured as the efficiency with whichL. plumulosus assimilated metals from particles using pulse-chase methods. Ag and Cd assimilation efficiencies were highest from bacterial exopolymeric coatings. Zn assimilation efficiency exhibited considerable interexperimental variation; the highest Zn assimilation efficiencies were measured from phytoplankton and processed sediment. In general, Ag and Cd assimilation efficiencies from phytoplankton were low and not related to the proportion of metal associated with cell cytosol or cytoplasm, a phenomenon reported for other particle-ingesting invertebrates. Amphipod digestive processes explain differences in Ag and Cd assimilation efficiencies between exopolymeric coatings and phytoplankton. Results highlight the importance of labile polymeric organic carbon sediment coatings in dietary metals uptake by this benthic invertebrate, rather than recalcitrant organic carbon, mineralogical features such as iron oxides, or phytoplankton.

We compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would better simulate chronic exposures to copepods and provide more sensitive and realistic information about contaminant effects on growth of copepod populations. Copepods were exposed to sediments from two sites, non-contaminated North Inlet Estuary (NIE), SC (USA), and highly contaminated Shipyard Creek (SYC), SC, and measured for lethal and sublethal test points. Fourteen and 21 day bioassays showed similar negative effects in SYC sediments for both species. Survival and reproductive success were higher in the 14 day than in the 21 day bioassay for both species, in both sediment types. The lower 21 day overall response was not indicative of enhanced bioassay sensitivity. The 14 day bioassay provides sufficient f 1 generation information to detect negative population level responses to contaminant mixtures.

Agricultural nonpoint source (NPS) runoff may result in significant discharges of pesticides, suspended sediments, and fertilizers into estuarine habitats adjacent to agricultural areas or downstream from agricultural watersheds. Exposure of estuarine fin fish and shellfish to toxic levels of pesticides may occur, resulting in significant declines in field populations. Integrated pest management (IPM), best management practices (BMP), and retention ponds (RP) are risk management tools that have been proposed to reduce the contaminant risk from agricultural NPS runoff into estuarine ecosystems. Field studies were conducted at three sites within coastal estuarine ecosystems of South Carolina (SC) from 1985 to 1990 that varied in terms of the amount and degree of risk reduction strategies employed. An intensively managed (IPM, BMP, and RP) agricultural treatment site (TRT) was studied for pesticide runoff impacts. From 1985 to 1987, there were minimal (some IPM and BMP) management activities at TRT, but from 1988 to 1990, TRT was managed using an intensive risk reduction strategy. A second unmanaged agricultural growing area, Kiawah (KWA), was also studied and compared with TRT in terms of pesticide runoff and the resulting impacts on grass shrimp ( Palaemonetes pugio) and mummichogs ( Fundulus heteroclitus). A third, non-agricultural, reference site (CTL) was used for comparing results from the managed and unmanaged agricultural sites. In situ toxicity tests and field samples of the grass shrimp populations were conducted at each site and compared in terms of survival and the effectiveness of current risk reduction strategies. Significant runoff of insecticides (azinphosmethyl, endosulfan, and fenvalerate) along with several fish kills were observed at TRT prior to the implementation of rigorous risk reduction methods. A significant reduction of in stream pesticide concentrations (up to 90%) was observed at TRT following the implementation of strict NPS runoff controls, which greatly reduced impacts on estuarine fish and shellfish. At the unmanaged KWA, continued impacts due to the runoff of these insecticides were observed, along with several fish kills. Additional monitoring indicated that gravid female grass shrimp populations from KWA had elevated levels of P-glycoprotein (P-gp), a multidrug resistance protein, which may transport various pesticides across cellular membranes. Comparison of field results with laboratory toxicity tests established that pesticide exposure was the primary cause of observed field impacts at each site. These findings clearly indicate the value of an integrated risk reduction strategy (BMP, IPM, and RP) for minimizing impacts from NPS agricultural pesticide runoff.

Microbial extracellular polymeric substances (EPS) are ubiquitous features in aquatic environments. Produced by surface-adherent bacteria and microalgae. EPS are often present as coatings on surfaces of sediment particles and exhibit high affinities for divalent cationic metals. Thus, EPS sediment coatings may participate in the fate of potentially toxic metals. We coated particulate silica (8-10 μm) with EPS produced by NISCI, a bacterium isolated from estuarine sediments, in order to measure the metal binding characteristics of these coatings. We used the radioisotope 109 Cd to measure effects of salinity (salinity = 2.5, 7.5, and 25‰). Cd concentration ([Cd] = 0.038, 5, and 50 mg/L). and pH (pH = 5, 6, 7, 8, and 9) on Cd sorption to EPS-coated (EPS-silica) silica and to noncoated silica (NC-silica). Also, Cd sorption by NISCI EPS coatings was compared to coatings of polymers formed by the bacterium Alteromonas atlantica and the alga Macrocystis porifera. Under all circumstances. EPS coatings increased the affinity of silica for Cd. Extracellular polymeric substance-particulate aggregates rapidly sorbed up to 90% of Cd from aqueous solution. Extracellular polymeric substance sediment coatings exhibited a maximum log distribution coefficient (K d ) of 6.5 at 2.5‰. Sorption of Cd to NC-silica was affected by salinity and metal concentration, whereas sorption of Cd to EPS-silica was only affected by salinity under high metal concentrations. Changes in pH had a dramatic effect on Cd sorption, with the proportion of free Cd to sorbed Cd changing from approximately 90% at pH 5 to 5% at pH 9. Desorption of Cd from EPS-silica was enhanced with increasing salinity. These experiments suggest that EPS coatings actively participate in binding dissolved overlying and pore-water metals in estuarine sediments.

Stable carbon isotopes (δ13C) were determined for autotrophic producers and animals from Lake Baikal (eastern Siberia), the deepest, the oldest and largest body of fresh water in the world. The extensive survey shows that the mean carbon isotope compositions of planktonic and benthic autotrophs differ in Lake Baikal by 21.5 ‰ the largest difference ever observed for lakes, thus giving an easy means to distinguish between pelagic and inshore carbon flows. Furthermore, our data give evidence that inshore macrofauna, which contributes greatly to the diversity within Baikalian animals, is supported by less abundant but highly diversified benthic flora, rather than by phytoplankton or terrigenous organic matter that dominate in the global carbon cycle of the lake.

Polycyclic aromatic hydrocarbon (PAH) bioaccumulation by the polychaete worm Streblospio benedicti (Webster) was measured under exposure to PAH-contaminated sediments in the field and for 28 d in the laboratory. Streblospio benedicti collected from field sediments contaminated at 2.94, 1.07, and l.52 μg g −1 fluoranthene (FLU), benz[a]anthracene (BAA), and benzo[a]pyrene (BAP), bioaccumulated those PAHs at 1.53, 0.215, and 0.332 μg g −1 , while worms isolated from less contaminated field sediments (0.399, 0.228, 0.288 μg g −1 FLU, BAA, and BAP) had FLU, BAA, and BAP body burdens of 0.543, 0.236, and 0.083 μg g −1 . Worms incubated for 28 d in PAH-spiked sediments (1.52, 0.991, 0.504 μg g −1 FLU, BAA, and BAP) bioaccumulated those PAHs at 0.382, 0.966, and 0.602 μg g −1 , respectively. Data normalization to organism lipid and sediment organic carbon (biota-sediment accumulation factors [BSAFs] strongly suggest that Streblospio PAH bioaccumulation was directly related to percent sediment organic carbon, but BSAFs were substantially lower than predicted by equilibrium partitioning theory. BSAFs decreased with increasing PAH log K ow , in worms collected from field sediments, but in spiked sediments BSAFs increased with increasing PAH hydrophobicity. This disparity may have been caused by insufficient spiked-sediment equilibration time (1.5h) in the case of the laboratory test sediments.

Meiofauna are a major food source for estuarine juvenile fish despite the fact that meiofauna often live in close contact with sediment-associated contaminants. Although there is laboratory evidence that fish feeding on contaminated meiofauna can build up significant contaminant body burdens, whether or not fish predation on meiofauna is affected by sediment contamination in the field has not been well established. To answer thls question, the number and taxa of meiobenthic prey items consumed by fish were compared between contaminated and uncontaminated habitats. A model predator, luvenile spot Leiostomus xanthurus (Pisces) was allowed to feed on natural meiobenthic communities in experimental sediment microcosn~s. Significantly more meiofauna were observed in the uncontaminated reference site (1060 nematodes per 10 cm2, 177 copepods per 10 cm2) than in the contaminated site (278 nematodes per 10 cm2. 97.5 copepods per 10 cm2). Although harpacticoid copepods were found in the foreguts of spot from both contaminated (mean 22.1 prey per fish) and uncontaminated (mean 13.7 prey per fish) sediments, there were few, if any, significant reductions in meiofauna abundance due to predation. There were differences between contaminated and uncontaminated sediments in taxa eaten by spot, but these differences were most likely due to differences between the meiofauna communities from the 2 sites, not differences in fish feeding behavior. Despite the potential adverse effects of eating meiofauna from contaminated sediments, juvenile spot do not avoid them.

Miobenthos occur at densities of >106/m2 in almost every uncontaminated estuarine sediment of the world, yet few studies have explored their utility for a multiple-species chronic bioassay of sediment contaminant effects. A new approach using laboratory-reared, whole-sediment meiobenthic microcosms was developed to holistically test the sublethal effects of chlorpyrifos on benthic copepod survival, age structure, and reproduction. Entire sediment-dwelling meiofaunal communities from a pristine estuarine preserve were cultured (i.e., net population gains were achieved in controls) for at least a full generation to the known 96-h copepod adult 25% lethal concentration and larval 50% lethal concentration of sediment-associated chlorpyrifos (21–33 μg/kg sediment). As an internal bioassay control, we added and cultured 100 gravid benthic copepods (Amphiascus tenuiremis) in each microcosm to assess the exact rather than relative effects of chlorpyrifos on population growth and dynamics. All but one copepod species reproduced and was cultured successfully for at least 21 d using these techniques. We found no chlorpyrifos effects on total meiobenthic copepod densities, but the predominant naturally occurring copepod Microarthridion littorale, known to be a major prey item of many juvenile fish, was significantly reduced in some chlorpyrifos-spiked microcosms. Other naturally occurring copepods were either unaffected or their growth was enhanced in the presence of chlorpyrifos. Amphiascus tenuiremis, known to be adversely affected at this concentration in 96-h static bioassays, increased dramatically in every microcosm. Species-specific responses of endemic copepods were masked when combined into the more commonly used coarse taxonomic category of total copepods.

Macrobenthos of the pristine North Inlet, SC, USA and urbanized Murrell's Inlet, SC, estuaries are predominated by the cosmopolitan spionid polychaete Streblospio benedicti. (Webster) Laboratory experiments were conducted to measure larval settlement and metamorphosis, and sub-adult bioaccumulation/growth rates of S. benedicti when exposed to controlled concentrations of sediment-associated polynuclear aromatic hydrocarbons. Larval settlement/metamorphosis was reduced, but not significantly affected (relative to controls) by IX, 5X and 10X background PAH mixture concentrations of the six most abundant sediment-associated PAHs found in urbanized Murrell's Inlet (1X = 0.9 μg PAH per g dry sediment). Bioaccumulation of the most abundant sediment-associated PAH, fluoranthene (FL), was very high in this PAH tolerant species—9.5–13.7X FL sediment concentrations after 28-day exposures. 28-day exposures to 0.26 and 2.4 μg FL · g−1 caused no significant mortality, and significantly effected positive average weight gains in S. benedicti up to 18 days exposure. However, dramatic and significant weight declines occurred from days 18–28 in both FL treatments. Such a strong tolerance of PAH may explain why these polychaetes are not limited to pristine geographic areas, but can, as numerous field studies have shown, recruit well into hydrocarbon-contaminated and organically enriched sediments.

The life-stage-specific acute toxicity of sediment-associated chlorpyrifos to the marine, infaunal copepod, Amphiascus tenuiremis, was assessed. Chlorpyrifos is a common-use, high K ow , organophosphate pesticide. Duplicate 96-h tests were conducted with each major life stage of the copepod (adult, copepodite, and nauplius) exposed to sediments spiked with chlorpyrifos. Calculated median lethal concentrations (LC50s) were 66, 74, and 40 μg chlorpyrifos per kilogram sediment for the adult, copepodite, and nauplius stages, respectively. Analysis of covariance and logistical regression analysis on the mortality data revealed significant (α = 0.05) sensitivity differences for the life stages. The nauplius stage was significantly more sensitive than either the adult or copepodite stages. However, the copepodite stage showed no significant sensitivity difference versus the adult stage. The lowest-observed-effect concentrations (LOECs) also showed these relationships, with the naupliar LOEC being almost three times lower than that of either the adult or copepodite stages. A predicted sediment quality criterion (SQC) based on the equilibrium partitioning theory (EqPT) for chlorpyrifos was calculated to be 38 μg chlorpyrifos per kilogram sediment. This calculated criterion, supposedly protective of most sediment-dwelling invertebrates, was only 2 μg/g lower than the LC50 for the nauplius life stage and far above the LOEC. An EqPT-derived SQC for chlorpyrifos clearly would not be protective of this meiobenthic copepod.

Environmentally controlled sedimentary microcosms were used to experimentally determine temperature, salinity, and depth-horizon effects on 613C DIC profiles of dissolved inorganic carbon (DIC) in sediment pore water (PW) and near-bottom water (BW). Simultaneously, benthic foraminifera1 populations of Ammonia beccarii were cultured and assayed for calcite 613C to establish how accurately foraminifera1 shells recorded BW-PW 813CDIC. One treatment population was restricted to the O-l -cm sediment depth; in another treatment, the population could freely "roam" up and down in the sediment microcosm. Pore-water DIC between the uppermost O-0.5-cm sediment layer and the overlying BW (i.e. 3 cm above the sediment-water interface) showed steep gradients of core-top AS13Cpw averaging -3.6-11.6Ym at 25°C and -2.6+0.5% at 20°C. Cor- respondingly, shell calcite 613C for A. beccarii collected from sediment microhabitats recorded a strong PW influence; V3C shell values averaged 1.1+0.8% lighter than BW V3C,, but 1.6 -L 0.6% enriched relative to average O-5-mm PW 613CDIC. Foraminifera restricted to the uppermost l-cm sediment depth throughout their lives exhibited shell calcite AV3C values not significantly different from foraminifera allowed to free- roam through the sediment column.

The effect of the dilational surface elasticity e on coating was investigated in two-layer slide coatings and single-layer slot and curtain coating experiments, respectively, up to 2 m/s. In the slide experiments both the surfactant concentration and e were varied in the lower layer. While the position of the static contact line (SCL) is a function of the elasticity modulus e, the dynamic contact line (DCL) position is insensitive to this variable. Also, the vacuum range increases with increasing the modulus e. Best correlations were obtained when e was measured at 1−2 Hz with a longitudinal wave generator. In curtain coating, the curtain edges can be stabilized and the wet thickness decreased by increasing the elasticity e. Also, in slot coating experiments the minimum wet thickness correlates with e as well. The modulus that best characterizes these coating techniques was determined at 0.1−0.2 Hz by means of a Langmuir trough.

Environmental context Studies of manufactured nanoparticles (NPs) in the environment have been performed almost exclusively at high NP concentrations. These data lead to misunderstandings related to NP fate and effects at relevant environmental concentrations, which are expected to be low. A better understanding of the concentration-dependent behaviour of NPs will improve our understanding of their fate and effects under environmentally realistic conditions. Abstract This rapid communication highlights the importance of nanoparticle concentration in determining their environmental fate and behaviour. Notably, two fate processes have been considered: dissolution and aggregation. The decrease in nanoparticle concentration results in increased dissolution and decreased aggregate sizes, inferring higher potential for environmental transport of nanoparticles.

Near infrared fluorescence (NIRF) spectroscopy is capable of sensitive and selective detection of semiconductive, single-walled carbon nanotubes (SWNT) using the unique electronic bandgap properties of these carbon allotropes. We reported here the first detection and quantitation of SWNT in sediment and biota at environmentally relevant concentrations using NIRF spectroscopy. In addition, we utilized this technique to qualitatively characterize SWNT samples before and after ecotoxicity, bioavailability and fate studies in the aquatic environment. Sample preparation prior to NIRF analysis consisted of surfactant-assisted high power ultrasonication. The bile salt sodium deoxycholate (SDC) enabled efficient extraction and disaggregation of SWNT prior to NIRF analysis. The method was validated using standard-addition experiments in two types of estuarine sediments, yielding recoveries between 66 ± 7% and 103 ± 10% depending on SWNT type and coating used, demonstrating the ability to isolate SWNT from complex sediment matrices. Instrument detection limits were determined to be 15 ng mL(-1) SWNT in 2% SDC solution and method detection limits (including a concentration step) were 62 ng g(-1) for estuarine sediment, and 1.0 μg L(-1) for water. Our work has shown that NIRF spectroscopy is highly sensitive and selective for SWNT and that this technique can be applied to track the environmental and biological fate of this important class of carbon nanomaterial in the aquatic environment.

As the use of single-walled carbon nanotubes (SWNTs) increases over time, so does the potential for environmental release. This research aimed to determine the toxicity, bioavailability, and bioaccumulation of SWNTs in marine benthic organisms at the base of the food chain. The toxicity of SWNTs was tested in a whole sediment exposure with the amphipod Ampelisca abdita and the mysid Americamysis bahia. In addition, SWNTs were amended to sediment and/or food matrices to determine their bioavailability and bioaccumulation through these routes in A. abdita, A. bahia, and the estuarine amphipod Leptocheirus plumulosus. No significant mortality to any species via sediment or food matrices was observed at concentrations up to 100 ppm. A novel near-infrared fluorescence spectroscopic method was utilized to measure and characterize the body burdens of pristine SWNTs in nondepurated and depurated organisms. We did not detect SWNTs in depurated organisms but quantified them in nondepurated A. abdita fed SWNT-amended algae. After a 28-d exposure to [(14) C]SWNT-amended sediment (100 µg/g) and algae (100 µg/g), [(14) C]SWNT was detected in depurated and nondepurated L. plumulosus amphipods at 0.50 µg/g and 5.38 µg/g, respectively. The results indicate that SWNTs are bioaccessible to marine benthic organisms but do not appear to accumulate or cause toxicity.

A study was undertaken to measure Aroclor 1254 body burdens in two benthic marine copepods, Amphiascus tenuiremis and Microarthridion littorale. A microextraction technique was developed which utilizes 100 μL of total extraction volume and as few as 20 copepods (approximately 25 μg of dry tissue mass). Copepods were homogenized and extracted in a 100-μL closed vial with alkaline media (4 M NaOH, 50 μL) and isooctane (50 μL) spiked with an internal standard (hexachlorobenzene), creating a colloidal suspension. After centrifugation, Aroclor 1254 quantification by GC-ECD was directly determined from the organic solvent phase

Two experiments were conducted using laboratory cultured meiofauna to measure bioturbation effects on cadmium partitioning. The benthic harpacticoid copepod, Amphiascus tenuiremis cf. Mielke, and the foraminiferan, Ammonia beccarii cf. Linne' served as bioturbators. The first experiment utilized single and combined species treatments which were compared to controls having no fauna. All treatments and controls used sediment spiked with Cd at the concentration at which 5% mortality occurs in the copepods (LC 5 ). Cadmium concentrations were measured in the overlying water, pore water, and sediment after 96 h to see if bioturbation altered the partitioning of cadmium. The second experiment employed the same design as the first except that the number of organisms used was tripled to simulate reported field densities. Results from the first experiment revealed significantly higher amounts of Cd in the pore waters of all treatments relative to the controls. There were also between treatment differences showing that copepod-only treatments resulted in the highest concentration of pore water Cd. With the second experiment, it was assumed that this bioturbation effect would be even greater due to the increased number of organisms used. However, this was not seen. Treatment pore water Cd concentrations of Experiment 2 were not significantly higher than like treatments from Experiment 1. Both experiments demonstrated that meiofaunal bioturbation has a significant effect on the partitioning of Cd in muddy sediments.

Estuarine sediments sequester heavy metals and non-ionic pollutants at concentrations manyfold greater than those in the water column. Sediment-associated pollutants probably have a greater impact on the wholly sediment-dependent meiobenthos than any other invertebrate group. In this study we compared acute effects of a highly lipophilic synthetic pyrethroid pesticide, fenvalerate (i.e. FV, log Kow = 6·20), on survival of a sediment-cultured meiobenthic copepod, Amphiascus tenuiremis, exposed to aqueous and sediment-associated FV phases. Empirical results were compared to predictions generated by the equilibrium partitioning approach to sediment quality criteria. Additionally, sediment-associated FV effects on a generic group of marine nematodes and one other species of field-collected benthic copepod, Paronychocamptus wilsoni, were tested. For sediment-associated FV, nematodes showed the highest acute sensitivity (96-h LC50 = 26·1 < 33·2 < 40·5 μg-FV g−1 carbon), followed by the field-collected copepod. Paronychocamptus wilsoni (96-h LC50: 61·9 < 73·9 < 91·7), and cultured copepod Amphiascus tenuiremis (96-h LC25: 56·2 < 84·2 < 147·4). In a major departure from equilibrium partitioning theory (EqPT) predictions, A. tenuiremis exposed to aqueous FV concentrations 7300 x higher than EqPT porewater values (i.e. 0·017 to 0·068 μg-FV liter−1) exhibited only 1–27% higher mean mortalities than in sediment-associated FV exposures. Based on EqPT, the high sediment-carbon (3·8%) particulate phase probably reduced porewater FV concentrations. However, the particulate phase in this study appeared a more important FV exposure route to the sediment-ingesting A. tenuiremis than porewater or even direct aqueous exposures.

Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose–response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10 µg L−1), delayed copepodite development (at 0.85 µg L−1), decreased reproductive success (at ≥ 0.39 µg L−1), and decreased offspring production (at 0.85 µg L−1). A reproductive median effective concentration (EC50) of 0.16 µg L−1 (95% CI: 0.12–0.21 µg L−1) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38 pg FS · µg−1 dry weight (95% CI: 0.27–0.52 pg FS · µg−1) or 2.8 pg FS · µg−1 lipid (95% CI: 2.2–3.6 pg FS · µg−1), respectively. Copepod log bioconcentration factor (BCF) = 4.11 ± 0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85 µg FS · L−1 (i.e., 9.6–10.2 µg FS · µg−1 lipid), and 50% population suppression at a CBR of 1.6 pg FS · µg−1 lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint—fertility rate. Environ. Toxicol. Chem. 2012; 31: 1076–1082. © 2012 SETAC