bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying pollution hot spots from polychlorinated biphenyl residues in birds of prey
Authors: Broughton Richard K. , Osborn Daniel , Shore Richard F. , Wienburg Claire L. , Wadsworth Richard A.
Published: November 2004

Techniques for determining whether patterns of points are random, clustered, or dispersed are well established; however, when the magnitude of the attribute at each location is also important, the situation is more problematic. The concentration of polychlorinated biphenyls (PCBs) in the livers of Eurasian sparrowhawks Accipiter nisus and common kestrels Falco tinnunculus has been determined for birds from all over Great Britain for several decades and forms a unique database. When mapped, there appears to be clusters of high values in some parts of the country. If these clusters are truly significant, then they may indicate pollution hot spots and possibly help identify undocumented sources of contamination. What constitutes a cluster is open to debate. We know something about the foraging behavior of birds of prey, but we do not know how many pollution sources (hot spots) there are, how long they persist, or over what area they may disperse PCBs. We used a Monte Carlo simulation approach to determine whether the visually prominent clusters of high PCB residues were significant features or merely illusions. The five largest nonoverlapping clusters (defined in terms of the total PCB concentration) were identified at a range of spatial scales. In addition to the total concentration and the number of observations, the weighted centroid of the clusters and which individual birds were involved were also recorded. This enabled us to determine the scale over which the candidate hot spot was stable. Comparing the magnitude of the observed clusters with those from the trial simulations determined the probability of nonrandomness in the original data set (at each spatial scale). Results showed that some clusters do exist but, in the majority of cases, apparent clusters identified by eye could not be considered an actual aggregation of high concentrations following spatial analysis.
Population-level ecological risk assessment of planar polychlorinated aromatic hydrocarbons in great cormorant (Phalacrocorax carbo) around Tokyo Bay, Japan
Authors: Murata Mariko , Masunaga Shigeki , Nakanishi Junko
Published: November 2004

Assessment of population-level ecological risk posed by planar polychlorinated aromatic hydrocarbons (p-PCAHs; including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxinlike polychlorinated biphenyls) in sediment of Tokyo Bay (Japan) and rivers via fish ingestion to the great cormorant (Phalacrocorax carbo) population was conducted by means of a probabilistic approach. Population decline risk was used as an indicator of population-level effects and compared with other indicators of effects. The increment of egg mortality risk posed by current p-PCAH levels was estimated to be 11.7%. This risk was interpreted in terms of both the increase of the risk of population decline in a 10-year period on a recently abundant cormorant population, and the reduction in population growth rate (r). Population decline risks of 20% and below were estimated to be 16% for the reference population and 32% for the exposed population, whereas the reduction in r was estimated to be 10%. The risk expressed in terms of population viability is a more susceptible measure and a more easily understandable indicator than both egg mortality risk as an individual-level risk and the reduction in r. Translating the effects due to pollutants into the risk on population viability will make ecological risk assessment more conducive to risk management.
Examination of reproductive endpoints in goldfish (Carassius auratus) exposed in situ to municipal sewage treatment plant effluent discharges in Michigan, USA
Authors: Giesy John P. G , Snyder Erin M. , Nichols Krista M. , Snyder Shane A. , Villalobos Sergio A. , Jones Paul D. , Fitzgerald Scott D.
Published: November 2004

Effects of representative mid-Michigan (USA) wastewater treatment plant (WWTP) effluents on the reproductive physiology of common goldfish (Carassius auratus) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17β-estradiol (E2), and testosterone (T), and evaluating gonad histology. Caged adult male and female goldfish were exposed for six weeks to WWTP effluents. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. There was differential growth and gonadal development among locations, which confounded the interpretation of biomarker responses. A linear contrast model was developed by analysis of covariance, and adjusted values were developed for concentrations of VTG, E2, and T in the plasma of both male and female fish. In general, VTG concentrations were significantly less in male than in female goldfish. Most concentrations of VTG in male goldfish were less than the method detection limit. There were no significant differences in plasma VTG of either male or female goldfish among locations or between sites at WWTPs and reference sites. Concentrations of E2 in the plasma of female goldfish were similar among WWTP sites, all of which were less than in females at a pond reference location. Concentrations of E2 in the plasma of male goldfish were similar at all WWTP locations, except for one, where they were greater. No consistent trends in hormone concentrations or gonadal histology could be attributed to putative endocrine disrupter exposure in WWTP effluents. The results indicate that the risk for estrogen agonist exposure below these mid-Michigan WWTPs is small.
Identification of toxic products of anthracene photomodification in simulated sunlight
Authors: Brack Werner , Altenburger Rolf , Küster Eberhard , Meissner Bettina , Wenzel Klaus-Dieter , Schüürmann Gerrit
Published: November 2004

Currently, the evidence of a rapid photomodification of anthracene under sunlight resulting in enhanced toxicity exists; however, the chemical causes of toxicity are still unknown. The present study aimed at filling this gap by irradiation of an anthracene suspension with simulated sunlight and subsequent effect-directed fractionation and analysis of toxic products with respect to the inhibition of bacterial energy metabolism of Vibrio fischeri, reproduction of the green algae Scenedesmus vacuolatus, and genotoxicity in the umuC test. Algal toxicity of anthracene was hardly modified by irradiation prior to testing and distributed over all fractions with emphasis on the fractions containing anthracene-9,10-dione and a photometabolite suggested to be 10-hydroxyanthrone. Bacterial toxicity and genotoxicity in contrast emerged only when anthracene was irradiated. Anthracene-1,4-dione, a sofar-unknown trace photometabolite, was identified as a very potent toxicant dominating the toxicity of photomodified anthracene to V. fischeri. In genotoxic fractions, 1-hydroxyanthracene-9,10-dione and 1,4-dihydroxyanthracene-9,10-dione were identified and confirmed as genotoxicants. The results stress the potential of effect-directed analysis approaches in contrast to mere chemical analysis in studies aiming at toxicologically relevant photomodified substances.
Dynamics of lipids and polychlorinated biphenyls in a baltic amphipod (Monoporeia affinis): A field study
Authors: Wiklund Ann-Kristin Eriksson , Wiklund Stig Johan , Axelman Johan , Sundelin Brita
Published: November 2004

Processes such as accumulation and elimination, which control tissue concentration of polychlorinated biphenyls (PCBs), were examined over time in an in situ study of the amphipod Monoporeia affinis. These processes were studied with respect to individual PCB congeners, percentage lipid and composition, and body weight. A secondary objective was to examine the impact of seasonal variability in percentage lipids and lipid composition on PCB concentration in two coexisting Baltic amphipods, M. affinis and Pontoporeia femorata. Polychlorinated biphenyl concentrations tended to be higher in P. femorata than in M. affinis, possibly because of P. femorata's lower respiration rate and larger size. The net accumulation of PCBs was congener dependent and negatively correlated to lipid concentration. The relation between the net concentration change rate of 16 PCB congeners over time and log Kow was not significant during the spring and summer months, a time when lipid accumulation and strong growth occur. In contrast, the net concentration change rate of the corresponding PCB congeners over time during autumn and early winter, that is, from the period before gonad maturation to the period after mating and early embryogenesis, showed a significant relation to log Kow (r2 = 0.62, p < 0.001, n = 16). During the latter period, amphipod lipid weight was reduced while the PCB body burden increased. Results strongly indicate that elimination rather than accumulation is the main process controlling amphipod body burden. This pattern results in a transfer of PCBs from the female to the developing embryos, which is reflected in high PCB body burden in newly released offspring.
Enantiomer-specific biomagnification of α-Hexachlorocyclohexane and selected chiral chlordane-related compounds within an arctic marine food web
Authors: Hoekstra Paul F. , Hara Todd M. O , Karlsson Heidi , Solomon Keith R. , Muir Derek C. G.
Published: November 2004

Concentrations of achiral and chiral organochlorine contaminants (OCs), including hexachlorocyclohexane isomers (HCH), chlordane congeners (cis- and trans-chlordane, cis- and trans-nonachlor, MC5, MC7, and U82), and related metabolites (oxychlordane [OXY] and heptachlor exo-epoxide [HEPX]), were quantified in seawater (100 L; n = 6) and biota from the coastal Beaufort–Chukchi Seas food web near Barrow (AK, USA). The biota included zooplankton (Calanus spp.; n = 5), fish species such as arctic cod (Boreogadus saida; n = 10), arctic char (Salvelinus alpinus; n = 3), and marine mammals including bowhead whales (Balaena mysticetus; liver: n = 23; blubber: n = 40), beluga whales (Delphinapterus leucas; blubber: n = 20), ringed seals (Phoca hispida; blubber: n = 20), and bearded seals (Erignathus barbatus; blubber: n = 7). The food web magnification factors (FWMFs) for HCHs and chlordane compounds ranged from 0.5 (γ-HCH) to 6.5 (HEPX) and were expected based on known recalcitrance and biotransformation of OCs. The enantiomer fractions (EFs) of all chiral OCs were near racemic (EF = 0.50) in seawater, zooplankton, and all fish analyzed. In contrast, the EFs for most OCs analyzed were nonracemic (EF ≠ 0.50) in the marine mammals blubber (range: 0.09–0.79) because of enantiomer-specific biotransformation and (or) accumulation. However, EF values were not significantly correlated with isotopically determined trophic level. The EFs for all chiral OCs (except α-HCH) in bowhead whale liver closely approximated the values in zooplankton, suggesting that the accumulation of chiral OCs from prey into this cetacean is not enantiomer specific. However, the modification of EFs from bowhead liver to blubber suggests that this species has the ability to enantioselectively biotransform and accumulate several chiral OC compounds.
Quantifying population recovery rates for ecological risk assessment
Authors: Barnthouse Lawrence W.
Published: November 2004

Ecological effects of modern agrochemicals are typically limited to brief episodes of increased mortality or reduced growth that are qualitatively similar to natural disturbance regimes. The long-term ecological consequences of agrochemical exposures depend on the intensity and frequency of the exposures relative to the rates of recovery of the exposed populations. This paper explores the feasibility of using readily available life history information to quantify recovery rates of aquatic populations. A simple modeling framework based on the logistic population growth model is used to compare population recovery rates for different types of organisms and to evaluate the influence of life history, initial percent reduction, disturbance frequency, and immigration on the time required for populations to recover from simulated agrochemical exposures. Recovery models are developed for aquatic biota ranging in size and longevity from unicellular algae to fish and turtles. Population growth rates and recovery times derived from life history data are consistent with measured recovery times reported in mesocosm and enclosure experiments, thus supporting the use of the models for quantifying population recovery rates for ecological risk assessment.
Effects of 25 pharmaceutical compounds to Lemna gibba using a seven-day static-renewal test
Authors: Brain Richard A. , Johnson David J. , Richards Sean M. , Sanderson Hans , Sibley Paul K. , Solomon Keith R.
Published: November 2004

Antibiotics are known to have antichloroplastic properties, but their effects on aquatic higher plants are virtually unknown. In order to address this issue, 25 pharmaceuticals, including 22 antibiotics, were assessed for phytotoxicity to the aquatic higher plant Lemna gibba. A 7-d static-renewal test was used, and plants were treated with 0, 10, 30, 100, 300, and 1,000 μg/L of pharmaceutical-containing growth media. Phytotoxicity was assessed using multiple growth and biochemical endpoints. Effective concentration (EC)50, EC25, and EC10 values as well as tests for significant differences between treatments and controls lowest-observed-effect concentration (LOECs) were calculated for each endpoint. Twelve different classes of antibiotics were assessed; however, only members of the fluoroquinolone, sulfonamide, and tetracycline classes of antibiotics displayed significant phytotoxicity. The most toxic members of each of these classes tested were lomefloxacin, sulfamethoxazole, and chlortetracycline, with wet weight EC25 values of 38, 37, and 114 μg/L, respectively. Injury symptoms were comparatively uniform and consistent among chemical classes while degree of phytotoxicity varied considerably. Both of these criteria varied markedly between classes. Wet mass was consistently the most sensitive endpoint above 100 μg/L; conversely, frond number was the most sensitive below 100 μg/L. Pigment endpoints were significantly less sensitive than growth endpoints.
Posidonia oceanica as a biomonitor of trace elements in the gulf of naples: Temporal trends by lepidochronology
Authors: Ancora Stefania , Bianchi Nicola , Butini Angela , Buia Maria Cristina , Gambi Maria Cristina , Leonzio Claudio
Published: November 2004

Levels of Hg, Cd, Pb, Cu, Zn, Fe, and Mn were assessed by using Posidonia oceanica as a bioindicator in the Gulf of Naples (southern Italy). Lepidochronology, which enables retroactive dating of scales and rhizomes of this seagrass, was combined with atomic spectrometry to assess temporal trends of trace elements in dated scales and rhizomes over a 10-year period. Lepidochronology occasionally has been used to monitor Hg in dated scales, but never has been used to determine concentrations of other trace elements in dated rhizomes. Data were compared between various structural parts of seagrass and between sampling sites. Concentrations of some elements found in dated scales or rhizomes showed a similar trend in most of the sites; increasing for Hg and Cu and decreasing for Pb, Fe, and Zn. Contaminant levels indicated by seagrass meadows varied from metal to metal. Concentrations of Hg, Cd, and Pb fell within the ranges measured in other areas considered to have low levels of heavy metal pollution, whereas Cu, Mn, and Zn had higher concentrations only in some years. However, on the basis of other studies, none of the sampling sites are considered to have high contamination levels.
Development of freshwater water-quality criteria for perchlorate
Authors: Dean Kirk E. , Palachek Randy M. , Noel Jill M. , Warbritton Ryan , Aufderheide John , Wireman Jody
Published: November 2004

The anion perchlorate (ClO4−) is an oxidizing component commonly used in solid propellants for rockets and missiles; in explosives, flares, fireworks, chemical processes, and automobile air-bag inflators; and for other assorted uses. With recent advances in analytical detection capability, perchlorate has been found in a variety of ground and surface waters throughout the United States. Because perchlorate has been associated with thyroid problems in humans and may have similar effects on wildlife, it is desirable to develop a water-quality criterion to assist in identifying concentrations of perchlorate in water likely to pose an ecological health risk. In the present study, we compiled all available data regarding the effects of perchlorate to aquatic organisms, and we performed additional toxicity and bioconcentration tests as required by the U.S. Environmental Protection Agency (U.S. EPA) for the development of water-quality criteria for aquatic life. A criterion maximum concentration of 20 mg/L and a criterion continuous concentration of 9.3 mg/L were calculated based on the test results. Although these are not formal Clean Water Act Section 304(a) criteria, which must be published by the U.S. EPA, these criteria may be useful in the determination of remedial action levels for contaminated sites, for National Pollutant Discharge Elimination System permit limits, and other water-quality management practices.
Elk exposure to arsenic in geothermal watersheds of Yellowstone National Park, USA
Authors: Kocar Benjamin D. , Garrott Robert A. , Inskeep William P.
Published: November 2004

Geothermal activity in Yellowstone National Park (WY, USA) (YNP) results in elevated levels of arsenic in surface waters, aquatic vegetation, and sediments in the Upper Madison River Basin. This study was conducted to determine concentrations of arsenic in the tissues, feces, and rumen contents of elk (Cervus elaphus) residing in the Madison—Firehole (MF) River basin, and to evaluate potential arsenic exposure pathways. Concentrations of total arsenic in MF elk were significantly higher than in control elk populations, and analysis of arsenic in surface waters, elk forage, sediments, and soils suggests that the predominant arsenic exposure pathways are forage species found in aquatic and riparian habitats. Analysis of arsenic species in selected plant and elk samples indicated that the ingested forms of arsenic are predominantly inorganic, while the appearance of dimethylarsonate in elk rumen and feces suggests that arsenic is subject to methylation reactions after ingestion, potentially contributing to arsenic detoxification. Arsenic:creatinine ratios of elk urine samples analyzed across three different winters increased during winter progression and were correlated with total snow water equivalent as an index of winter severity. Exposure to arsenic and other trace elements (fluorine) may contribute to the previously observed decreased life expectancy of MF elk relative to control populations.
Influence of soil moisture on linear alkylbenzene sulfonate-induced toxicity in ammonia-oxidizing bacteria
Authors: Nielsen Klaus B. , Brandt Kristian K. , Jacobsen Anne-Marie , Mortensen Gerda K. , Sørensen Jan
Published: November 2004

Moisture affects bioavailability and fate of pollutants in soil, but very little is known about moisture-induced effects on pollutant toxicity. We here report on a modifying effect of moisture on degradation of linear alkylbenzene sulfonates (LASs) and on their toxicity towards ammonia-oxidizing bacteria (AOB) in agricultural soil. In soil spiked with two LAS levels (250 or 1,000 mg/kg) and incubated at four different moisture levels (9–100% of water-holding capacity), degradation was strongly affected by both soil moisture and initial LAS concentration, resulting in degradation half-lives ranging from 13 to more than 160 d. Toxicity towards AOB assessed by a novel Nitrosomonas europaea luxAB-reporter assay was correlated to total LAS concentration, indicating that LAS remained bioavailable over time without accumulation of toxic intermediates. Toxicity towards indigenous AOB increased with increasing soil moisture. The results indicate that dry soil conditions inhibit LAS degradation and provide protection against toxicity within the indigenous AOB, thus allowing for a rapid recovery of this population when LAS degradation is resumed and completed after rewetting. We propose that the protection of microbial populations against toxicity in dry soil may be a general phenomenon caused primarily by limited diffusion and thus a low bioavailability of the toxicant.
Aquatic ecotoxicological indicators in life-cycle assessment
Authors: Pennington David W. , Payet Jerome , Hauschild Michael
Published: November 2004

This paper compares available options for the aquatic ecotoxicological effect factor component in life-cycle assessment (LCA). The effect factor is expressed here as the change in risk per unit change in cumulative exposure, Δeffect/Δexposure. The comparison is restricted to approaches linked, implicitly as well as explicitly, to species-sensitivity distributions (SSDs). This draws on recent insights for chemical mixtures and identifies the implications of different model choices. In spite of the many options, assumptions, and areas for further research, it is concluded that a single effect factor basis represents the best available practice for use in LCA at this time, ΔPAFms/ΔC = 0.5/HC50, where ΔPAFms is the change in the (potentially affected) fraction (PAF) of species that experiences an increase in exposure above a specified effect level, accounting for the presence of complex background mixtures (ms), ΔC is the change in cumulative exposure concentration of the chemical of interest, and HC50 is the median, chronic hazardous concentration for regional, multiple-species systems. The resultant aquatic effect factors are risk-based and can be estimated readily for many chemicals using available methods, without the need to describe the entire SSDs and without the need for additional data. For example, the octanol–water partitioning coefficient provides a sufficient estimation basis for about 50% of existing chemicals that have a narcosis mode of action. This also is relevant in LCA for chemicals that are at low concentrations in the environment, concentrations below the biological thresholds at which more specific modes of action would be of relevance.
Potency and characterization of estrogen-receptor agonists in United Kingdom estuarine sediments
Authors: Thomas Kevin V. , Balaam Jan , Hurst Mark , Nedyalkova Zoya , Mekenyan Ovanes
Published: November 2004

The activity of estrogen-receptor (ER) agonists in sediments collected from the United Kingdom (UK) estuaries was assessed using the in vitro recombinant yeast estrogen screen (YES assay). The YES assay was successfully used to determine the in vitro ER agonist potency of pore waters and solvent extracts of sediments collected from UK estuaries. Estrogen-receptor agonists were detected in 66% of the pore water samples and in 91% of the sediment solvent extracts tested. The pore waters tested had ER agonist potencies from less than 2 to 68 ng 17β-estradiol (E2) L−1, whereas sediment extracts had potencies from less than 0.2 to 13 μg E2 kg−1. A toxicity identification evaluation approach using bioassay-directed fractionation was used in an attempt to identify the ER agonists in extracts of sediments collected from the Tyne and Tees estuaries (UK). Gas chromatography—mass spectrometry was used to provide lists of compounds in the fractions obtained that were evaluated for known ER agonist activity using published data and an ER quantitative structure-activity relationship model. Toxicity identification evaluation characterization failed to identify any ER agonists in pore water extracts; however, three compounds in sediment solvent extracts were identified as ER agonists. Nonylphenol, cinnarizine, and cholesta-4,6-dien-3-one were identified in the sample collected from the Tyne estuary. Important ER agonist substances that contaminate marine sediments remain unidentified. The present study as well as previous work on effluents point toward the involvement of natural products in the estrogenic burdens of marine sediments. Further work is required to establish the relative contribution of natural products and anthropogenic chemicals to current environmental impacts in the context of the Oslo and Paris Commission strategy to eliminate hazardous substances by 2020.
Competition effects for copper between soil, soil solution, and yeast in a bioassay for Folsomia candida Willem
Authors: van der Zee Sjoerd E. A. T. M. , Temminghoff Erwin J. M. , Marinussen Mari P. J. C.
Published: November 2004

We investigated the accumulation of copper (Cu) by the springtail Folsomia candida Willem, if exposed to Cu-con-taminated sandy soil with yeast as a food source. Commonly, the dissolved and the easily desorbed Cu fractions are assumed to be available for uptake, and as both fractions depend on pH, a pH dependency of copper uptake and accumulation is expected. In recent studies with springtails this dependency was not observed. To explain this, we show that both the adsorption of copper by yeast and by soil is indeed pH dependent; however, these dependencies differ. Addition of yeast as a food source to copper-contaminated soil leads to competition for copper by yeast and soil that suppresses the pH dependency of copper adsorption by yeast. This may cause a pH dependency not to be observed in copper accumulation by springtails if they predominantly feed on yeast in bioassays. We conclude that the addition of artificial food sources in bioassays may affect the cause–effect relationships that are investigated. A combination of (soil) chemical experimentation and modeling and ecotoxicological studies may help in identifying such bias and, therefore, with interpreting bioassays.
A relationship between gill silver accumulation and acute silver toxicity in the freshwater rainbow trout: Support for the acute silver biotic ligand model
Authors: Morgan Tammie P. , Wood Chris M.
Published: November 2004

Rainbow trout were exposed to a range of silver concentrations (as AgNO3) in flowing synthetic soft water (0.05 mM Na+, 0.05 mM Cl−, 0.05 mM Ca2+, 0.02 mM Mg2+, 0.02 mM K+, pH 7.0, approximately 0.7 mg C/L dissolved organic carbon, 10 mg CaCO3/L, 10 ± 2°C) to investigate a possible relationship between short-term gill silver accumulation (3 h or 24 h) and acute silver toxicity (96-h mortality). We also investigated potential relationships between gill silver accumulation and inhibition of Na+ uptake plus inhibition of gill Na+K+-adenosine triphosphatase (ATPase) activity. The 96-h median lethal concentration (LC50) values were 13.3 μg total Ag L−1 and 3.3 μg dissolved Ag L−1. A relationship was demonstrated between 3-h and 24-h gill silver accumulation and 96-h mortality. A relationship also was demonstrated between gill silver accumulation and inhibition of Na+ uptake at 24 h of exposure. No relationship between gill silver accumulation and inhibition of gill Na+K+-ATPase activity was found. The 96-h median lethal gill accumulation (LA50) values of 129 (at 3 h) and 191 ng g−1 (at 24 h) and a conditional equilibrium binding constant of 8.0 for Ag+ binding to the gills were calculated. These observations support use of the silver biotic ligand model (BLM) as a regulatory tool to predict acute silver toxicity.
Enhancing the attenuation of explosives in surface soils at military facilities: Sorption-desorption isotherms
Authors: Hatzinger Paul B. , Fuller Mark E. , Rungmakol Darin , Schuster Rachel L. , Steffan Robert J.
Published: November 2004

The primary objective of the present study was to develop inexpensive soil amendments that can be applied to enhance the adsorption of energetic compounds on military training ranges, thus limiting the potential for these compounds to migrate to groundwater. Adsorption and desorption isotherms were determined for 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine with a wide variety of natural and man-made adsorbents, including wheat straw, sawdust, peat moss, ground rubber tires, and clays. Among the various adsorbents tested, peat moss proved to be the most effective sorbent for the three explosives. The adsorption coefficients (Ksd) for TNT and RDX with peat (310 and 87 L/kg, respectively) were at least two orders of magnitude higher than that determined for adsorption of these energetics with two surface soils. The adsorption-desorption isotherms for the explosives showed considerable hysteresis (Ksd < Kdd) with some of the solid adsorbents, suggesting that the sorption process is not readily reversible but, rather, that some fraction of the adsorbed contaminant is either irreversibly bound or present as a slowly desorbed fraction. The data indicate that the application of specific adsorbents to soils at military impact ranges may significantly improve the protection of local groundwater resources.
Influences of sedimentary organic matter quality on the bioaccumulation of 4-nonylphenol by estuarine amphipods
Authors: Hecht Scott A. , Gunnarsson Jonas S. , Boese Bruce L. , Lamberson Janet O. , Schaffner Christian , Giger Walter , Jepson Paul C
Published: November 2004

Nonylphenol (NP) is a moderately persistent, hydrophobic chemical with endocrine-disrupting and acute narcotic effects in aquatic biota. Concern exists about the ultimate fate of NP in aquatic ecosystems and the potential for bioaccumulation by benthic biota from the sediment with the potential for further transfer to higher trophic levels. Our goals were to determine if benthic amphipods bioaccumulate significant amounts of NP from sediment and to determine how additions of organic matter influence NP bioaccumulation by amphipods. Estuarine sediment was spiked with 14C-NP and enriched with two types of organic carbon (OC) sources of different nutritional qualities. Macrophytic algae (Ulva species) were used as a labile and nutritious OC source. Wood lignins were used as a refractory and low-nutrition OC source. Nonylphenol bioaccumulation was measured in Eohaustorius estuarius, Grandidierella japonica, and Corophium salmonis after 16 d of exposure. Nonylphenol accumulation was inversely proportional to OC quantity, but was unaffected by OC nutritional quality. Significant differences were found in the accumulation patterns between the three amphipod species. Mean biota-sediment accumulation factors ranged from 8.1 to 33.9 in E. estuarius, from 4.6 to 17.2 in G. japonica, and averaged 7.1 in male C. salmonis and 16.0 in female C. salmonis. These accumulation factors indicate that estuarine amphipods could constitute an important source of NP to higher trophic levels, such as juvenile fish.
Assessing behavioral toxicity with Caenorhabditis elegans
Authors: Anderson Gary L. , Cole Russell D. , Williams Phillip L.
Published: November 2004

Behavior, even in simple metazoans, depends upon integrated processesat the subcellular, cellular, and organismal level, and thus is susceptible to disruption by a broad spectrum of chemicals. Locomotor behavior (movement) of the small free-living nematode Caenorhabditis elegans has proven to be useful in assessing toxicity. Recently reported observations suggest that behavioral change (reduced movement) occurs after 4 h of exposure to heavy metals, and that with abbreviated exposure, the concentration-response relationship for Pb (a known neurotoxic metal) differs from that for Cu. In this study, movement was evaluated after 4-h exposures for nine compounds from three chemical classes: organic pesticides, organic solvents, and heavy metals. Concentration-dependent reduction of movement was observed for all test compounds with the exception of mebendazole, for which test concentrations were limited by solubility. Within each chemical class, movement was more sensitive to the neurotoxic compounds than to substances not believed to be neurotoxic, as evidenced by behavioral effective concentration to reduce average worm movement to 50% of the control movement values (e.g., levamisole and chlorpyrifos < mebendazole, ethanol and acetone < dimethylsulfoxide, and Pb and Al < Cu). These observations are discussed as they relate to the use of acute behavioral tests in assessing general chemical toxicity, and the enhanced value of 4-h testing for the detection of neural toxicants.
Acute and chronic toxicity of five selective serotonin reuptake inhibitors in Ceriodaphnia dubia
Authors: Henry Theodore B. , Kwon Jeong-Wook , Armbrust Kevin L. , Black Marsha C
Published: November 2004

Contamination of surface waters by pharmaceutical chemicals has raised concern among environmental scientists because of the potential for negative effects on aquatic organisms. Of particular importance are pharmaceutical compounds that affect the nervous or endocrine systems because effects on aquatic organisms are possible at low environmental concentrations. Selective serotonin reuptake inhibitors (SSRIs) are drugs used to treat clinical depression in humans, and have been detected in low concentrations in surface waters. In this investigation, the acute and chronic toxicity of five SSRIs (fluoxetine, Prozac®; fluvoxamine, Luvox®; paroxetine, Paxil®; citalopram, Celexa®; and sertraline, Zoloft®) were evaluated in the daphnid Ceriodaphnia dubia. For each SSRI, the 48-h median lethal concentration (LC50) was determined in three static tests with neonate C. dubia, and chronic (8-d) tests were conducted to determine no-observable-effect concentrations (NOEC) and lowest-observable-effect concentrations (LOEC) for reproduction endpoints. The 48-h LC50 for the SSRIs ranged from 0.12 to 3.90 mg/L and the order of toxicity of the compounds was (lowest to highest): Citalopram, fluvoxamine, paroxetine, fluoxetine, sertraline. Mortality data for the 8-d chronic tests were similar to the 48-h acute data. The SSRIs negatively affected C. dubia reproduction by reducing the number of neonates per female, and for some SSRIs, by reducing the number of broods per female. For sertraline, the most toxic SSRI, the LOEC for the number of neonates per female was 0.045 mg/L and the NOEC was 0.009 mg/L. Results indicate that SSRIs can impact survival and reproduction of C. dubia; however, only at concentrations that are considerably higher than those expected in the environment.
Maternal transfer efficiency and transgenerational toxicity of methylmercury in Daphnia magna
Authors: Tsui Martin T.K. , Wang Wen-Xiong
Published: November 2004

We examined maternal transfer efficiency, retention by subsequent generations, and transgenerational toxicity of methylmercury (CH3Hg or MeHg) in a population of freshwater zooplankton (Daphnia magna). The effect of dietary MeHg residence time in the daphnids on the efflux system also was quantified. After ingesting a relatively high dosage of MeHg, D. magna exhibited a reduction of live neonates and an increase of undeveloped eggs (or embryos), which reflected the sublethal toxicity of MeHg. The daily maternal transfer efficiency of MeHg to both reproductive outputs ranged from 0.42 to 4.9% over different ages of the parental daphnids, which was dependent on the daily reproductive output. During the lifetime of D. magna, reproduction contributed to 10.8% ± 1.74% (n = 3) SD of total MeHg loss from the parental daphnids. The percentage of MeHg retention by the second generation (F1) of D. magna (40–60%) was generally higher than that by the parental generation (F0; ˜25%) after 20 d of depuration. Methylmercury imposed sublethal toxicity to the F0 and F1 generations, but a smaller effect was observed on the F2 generation. Because of the very low MeHg body burden in the subsequent generations, we hypothesized that factors other than MeHg, such as nutritional deficiency in the offspring contributed to the transgenerational toxicity. Different MeHg residence times did not significantly affect the efflux rate of MeHg but did significantly affect the relative importance of reproduction as the elimination pathway for MeHg. Based on the MeHg body burden of neonates, we estimated that MeHg took 2.5 to 3.0 d to be optimally transferred from assimilation (e.g., gut) to the site of egg development (e.g., brood chamber) in D. magna. Our study demonstrated that maternal transfer of MeHg in freshwater zooplankton is an important predictor of MeHg concentration in their offspring and is a time-dependent and highly dynamic process.
In situ reproduction, abundance, and growth of young-of-year and adult largemouth bass in a population exposed to polychlorinated biphenyls
Authors: Reiser Dudley W. , Greenberg Emily S. , Helser Thomas E. , Branton Margaret , Jenkins Kenneth D.
Published: November 2004

We conducted a two-year field study (2000–2001) in the Housatonic River, Massachusetts (USA) to determine if we could detect in situ population-level effects on largemouth bass (Micropterus salmoides) exposed to elevated levels of polychlorinated biphenyls (PCBs). Calculated whole-body PCB concentrations in adult bass in 2002 averaged 121 mg/kg (range = 34–556 mg/kg). Polychlorinated biphenyl concentrations in young-of-year (YOY) composites in 2000 and 2002 averaged 28 mg/kg (range = 21–41 mg/kg) and 19 mg/kg (range = 16–24 mg/kg), respectively. Laboratory studies of fish have reported PCB toxicity at exposure levels below and within the range of those found in the Housatonic River. We evaluated five field-derived metrics: reproductive activity, relative abundance of YOY, YOY growth rates, adult growth, and adult condition to determine whether we could detect effects of PCBs in the largemouth bass population. These computed metrics, when compared with data sets assembled for numerous largemouth bass populations in North America, provided no evidence of population-level impairment. Results of this study suggest that PCB tissue concentrations associated with effects in laboratory studies do not necessarily translate to detectable effects on largemouth bass populations in their natural environment.
Evaluation of the protective effects of reactive sulfide on the acute toxicity of silver to rainbow trout (Oncorhynchus mykiss)
Authors: Mann Reinier M. , Ernste Mike J. , Bell Russell A. , Kramer James R. , Wood Chris M.
Published: November 2004

Acute 96-h toxicity tests were performed with juvenile rainbow trout (Oncorhynchus mykiss) exposed to AgNO3 in either the absence or the presence of 100 nM reactive sulfide to evaluate the protective effect of aqueous sulfides against ionic Ag toxicity. The sulfide was presented in the form of zinc sulfide (ZnS) clusters under oxic conditions. Silver was lost from the water column during the course of the experiment, so mean measured Ag concentrations were used to generate all median lethal concentration (LC50) data. The system was complicated in that Ag2S precipitated because of the need for large amounts of Ag to obtain lethal effects in the presence of ZnS. Some of the losses of Ag could be explained by complexation with ZnS and formation of solid Ag2S. Other losses were probably the result of partial adsorption to exposure-chamber walls or to complexation with ligands or functional groups within organic material produced by the fish. The LC50 (95% confidence interval) values generated using measured concentrations for total Ag were 139 (122-162) nM in the absence of sulfide and 377 (340-455) nM in the presence of 100 nM sulfide. The LC50 values generated using measured concentrations from filtered (pore size, 0.45 μm) water samples were 122 (105-145) nM in the absence of sulfide and 225 (192-239) nM in the presence of 100 nM sulfide. These results suggest a stoichiometric protection of sulfides up to a 2:1 ratio of Ag:sulfide. Greater accumulation of Ag at the gills was measured in fish exposed to AgNO3 in the presence of sulfide.
Ecological risk assessment of persistent toxic substances for the clam Tapes philipinarum in the lagoon of venice, italy
Authors: Micheletti Christian , Critto Andrea , Carlon Claudio , Marcomini Antonio
Published: November 2004

Because of contamination of sediments of the Lagoon of Venice, Italy, by inorganic pollutants (e.g., arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc) and organic pollutants (e.g., polychlorobiphenyls), as well as the ecological and economical relevance of the edible clam Tapes philipinarum, an ecological risk assessment was undertaken to ascertain the extent of bioaccumulation that would pose a significant risk. Risk was estimated by means of toxic units and hazard quotient approaches, by comparing the exposure concentration with the effect concentration. Clam exposure was estimated by applying previous results based on bioaccumulation spatial regression models. In addition, a comparison was made between sum of dioxin-like polychlorinated biphenyl (PCB) congeners and total PCB bioaccumulation provided by spatial regression models and by a partitioning model. The effect concentrations were calculated as tissue screening concentrations, as the product of pollutant sediment quality criteria and the bioaccumulation factor. Finally, the cumulative risk posed by selected inorganic pollutants and total PCBs was estimated and a map of risk was drawn. The resulting chemicals of potential ecological concern were mercury, cadmium, arsenic, and nickel, as well as, to a lesser extent, total PCBs.
Universal predictive models on octanol-air partition coefficients at different temperatures for persistent organic pollutants
Authors: Chen Jingwen , Harner Tom , Ding Guanghui , Quan Xie , Schramm Karl-Werner , Kettrup Antonius
Published: November 2004

Owing to the importance of octanol-air partition coefficients (KOA) in describing the partition of organic pollutants from air to environmental organic phases, the paucity of KOA data at different environmental temperatures, and the difficulty or high expenditures involved in experimental determination, the development of predictive models for KOA is necessary. Approaches such as this are greatly needed to evaluate the environmental fate of the ever-increasing list of production chemicals. Partial least squares (PLS) regression with 18 molecular structural descriptors was used to develop predictive models based on directly measured KOA values of selected chlorobenzenes, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes, polychlorinated dibenzo-p-dioxins/dibenzofurans, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, and organochlorine pesticides (OPs). An optimization procedure resulted in two temperature-dependent universal predictive models that explained at least 91% of the variance of log KOA. Model 1 was the more general of the two models that could be used for all the persistent organic pollutant (POP) classes investigated. Although model 1 performed poorly for select OPs, this was attributed to wide variability in structural types within this subset of POPs and their diversity compared to the other POP classes that were investigated. The exclusion of the structurally complex OP subset resulted in a more precise model, model 5. Intermolecular dispersive interactions (induced dipole-induced dipole forces) between octanol and solute molecules play a decisive role in governing KOA and its temperature dependence. Further investigations are needed to better characterize the steric structures of the POPs under study, especially of OPs.
Sorption of 2,4′-dichlorobiphenyl and fluoranthene to a marine sediment amended with different types of black carbon
Authors: Burgess Robert M. , Ryba Stephan A. , Perron Monique M. , Tien Rex , Thibodeau Laura M. , Cantwell Mark G.
Published: November 2004

Recents studies demonstrate that sedimentary black carbon (BC) affects the sorption of some hydrophobic organic contaminants (HOCs) to a greater extent than sedimentary organic carbon (OC). Among HOC, polycyclic aromatic hydrocarbons (PAHs) are known to interact extensively with BC. Currently, data on the sorption of various kinds of HOCs to different types of BC are limited. In this study, we amended a marine sediment with BC from several different sources, humic acid, and inert sand. Equilibration studies with 14C fluoranthene and the polychlorinated biphenyl (PCB) 3H 2,4′-dichlorinated biphenyl were performed to determine the magnitude of sorption as a function of contaminant and BC type. The magnitude of sorption to the BC-amended sediments was greater for the PAH than the PCB as compared to the sediment alone, humic acid, and sand. For example, differences between the log partition coefficient (KP) for the PAH and PCB ranged from 0.41 to 0.69 log units for humic acid and sand treatments, while differences ranged from 0.88 to 1.57 log units for the BC-amended sediments. As a result, BC-normalized partition coefficients (log KBC) for the PAH averaged 6.41, whereas the PCB log KBC values averaged 5.33. These results demonstrate that PAH sorption and most likely bioavailability are influenced strongly by the presence of BC of different types, while sorption of a nonplanar PCB was affected to a lesser degree.
Relationship between metabolism and bioaccumulation of benzo[α]pyrene in benthic invertebrates
Authors: Rust Aaron J. , Burgess Robert M. , Brownawell Bruce J. , McElroy Anne E.
Published: November 2004

The potential influence of polycyclic aromatic hydrocarbon (PAH) metabolism on bioaccumulation is well accepted, but rarely has been examined in many species of benthic invertebrates that commonly are found in contaminated sediments, or used in bioaccumulation or toxicity tests. In this study, the relative ability of 11 species of near-shore benthic invertebrates to metabolize and bioaccumulate a model PAH, benzo[α]pyrene (BαP), was evaluated. Species examined included six polychaetes (Clymenella torquata, Nereis virens, Nereis succinea, Nephtys incisa, Spio setosa and Cirriformia grandis), three bivalves, (Macoma balthica, Mya arenaria, and Mulinia lateralis), and two amphipods (Ampelisca abdita and Leptocheirus plumulosus). After 7 d of exposure to sediments spiked with radiolabeled BαP, metabolites comprised between 6.1% (Clymenella torquata) to 85.7% (Nereis succinea) of total accumulated BαP, with individual species from the same phylogenetic groups showing large differences in their ability to metabolize this PAH. Bioaccumulation factors (BαP in tissue/BαP in sediment) were inversely related to the species' ability to metabolize PAH, highlighting the importance of considering metabolism when interpreting bioaccumulation across several species. These data argue strongly against the continued use of the large polychaete Nereis virens, one of the species showing the greatest ability to metabolize BαP, for bioaccumulation testing when PAHs are being considered. Other commonly used test species had relatively low levels of metabolism (Ampelisca abdita, Leptocheirus plumulosus, and Macoma balthica), supporting their use in evaluation of potential PAH impact on the environment.
Oil spill impact modeling: Development and validation
Authors: French-McCay Deborah P.
Published: November 2004

A coupled oil fate and effects model has been developed for the estimation of impacts to habitats, wildlife, and aquatic organisms resulting from acute exposure to spilled oil. The physical fates model estimates the distribution of oil (as mass and concentrations) on the water surface, on shorelines, in the water column, and in the sediments, accounting for spreading, evaporation, transport, dispersion, emulsification, entrainment, dissolution, volatilization, partitioning, sedimentation, and degradation. The biological effects model estimates exposure of biota of various behavior types to floating oil and subsurface contamination, resulting percent mortality, and sublethal effects on production (somatic growth). Impacts are summarized as areas or volumes affected, percent of populations lost, and production foregone because of a spill's effects. This paper summarizes existing information and data used to develop the model, model algorithms and assumptions, validation studies, and research needs. Simulation of the Exxon Valdez oil spill is presented as a case study and validation of the model.