bluuebunny/crossref_metadata_2025 huggingface dataset:
Biotransformation of 2,4,6–trinitrotoluene in Anabaena sp. cultures
Authors: Pavlostathis Spyros G , Jackson Gardner H
Published: March 2010

The transformation of 2,4,6-trinitrotoluene (TNT) was investigated in cultures of the cyanobacterium Anabaena sp. by conducting a series of batch assays. 2,4,6-Trinitrotoluene was added to Anabaena sp. cultures in single and consecutive additions, at various initial concentrations, to determine its transformation kinetics, to identify products formed, to evaluate potential toxicity, and to determine the effect of light deprivation on the TNT transformation process. 2,4,6-Trinitrotoluene disappearance occurred only in the presence of Anabaena sp. cultures maintained under a normal 16-h photoperiod. Toxicity leading to culture chlorosis and death was observed in batch systems with an initial TNT concentration greater than 10 mg/L. A low rate and extent of TNT disappearance was observed in light-deprived cultures, which were inhibited even at low TNT concentrations (i.e., <4 mg/L). At pH values between 7.5 and 8.5, azoxy-tetranitrotoluene isomers were detected in both the culture medium and solvent extracts of biomass and accounted for only 20 and 4.4% of the initially added TNT moles, respectively. At a culture pH range between 5.6 and 5.9, achieved by aeration with a 5% CO2/air mixture, hydroxylaminodinitrotoluene equimolar to the TNT addition was produced and then depleted from the culture medium with prolonged incubation. Although TNT reduction in Anabaena sp. cultures occurred, yielding low levels of azoxy-tetranitrotoluene isomers or hydroxylaminodinitrotoluene (depending on the culture pH conditions), uptake and other transformation reactions of TNT and/or its transformation products by Anabaena sp. may have taken place. Based on a less than 15% observed increase of biomass concentration over the relatively short incubation periods (usually <6 h) and by considering the mean biomass concentration constant, the TNT disappearance rate followed pseudo-first-order kinetics. The biomass carbon-normalized TNT disappearance rates in Anabaena sp. cultures were about three orders of magnitude higher than previously reported TNT disappearance rates obtained in batch cultures of aquatic plants.
Comparison of organochlorine contaminants among sea otter (Enhydra lutris) populations in California and Alaska
Authors: Bacon Corinne E , Jarman Walter M , Estes James A , Simon Mary , Norstrom Ross J
Published: March 2010

Organochlorine pesticides, polychlorinated biphenyls (PCBs) including non-ortho PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were measured in sea otter liver tissue from California, southeast Alaska, and the western Aleutian archipelago collected between 1988 and 1992. Average total dichlorodiphenyltrichloroethane concentrations for California otters (850 μg/kg wet weight) were over 20 times higher than in Aleutian otters (40 μg/kg) and over 800 times higher than otters from southeast Alaska (1 μg/kg). Levels for total PCBs in Aleutian otters (310 μg/kg) were 1.7 times higher than levels in California otters (190 μg/kg) and 38 times higher than otters from southeast Alaska (8 μg/kg). Levels for PCDD and PCDF were extremely low in all otter populations. Levels of PCBs in Aleutian and Californian otters are abnormally high when compared with southeast Alaskan otters. The source of PCBs to the Aleutian Islands remains unclear and vital to understanding the potential impacts to sea otters.
Cytochrome P4501A induction, benzo[a]pyrene metabolism, and nucleotide adduct formation in fish hepatoma cells: Effect of preexposure to 3,3′,4,4′,5-pentachlorobiphenyl
Authors: Smeets Jean M W , Voormolen Adriaan , Tillitt Donald E , Everaarts Jan M , Seinen Willem , van den Berg Martin
Published: March 2010

In PLHC-1 hepatoma cells, benzo[a]pyrene (B[a]P) caused a maximum induction of cytochrome P4501A (CYP1A) activity, measured as ethoxyresorufin O-deethylation (EROD), after 4 to 8 h of exposure, depending on the B[a]P concentration. The decline of EROD activity at longer exposure times was probably caused by the rapid metabolism of B[a]P in this system (57% metabolism within 4 h incubation). In subsequent experiments, PLHC-1 cells were preinduced with PCB 126 for 24 h and then received a dose of 10, 100, or 1,000 nM 3H-B[a]P. A 1-nM concentration of PCB 126 caused an 80-fold induction of CYP1A activity, resulting in an increase in B[a]P metabolism of less than 10%, except at the highest concentration of B[a]P (1,000 nM), where a 50% increase was observed. In another experiment, an 80-fold induction of CYP1A activity caused a 20% increase in the metabolism of B[a]P (100 nM), and RNA adduct formation was increased approximately twofold. These results indicate that, at exposure concentrations up to 100 nM B[a]P, CYP1A activity is not rate limiting for B[a]P metabolism. Furthermore, CYP1A seems to also be specifically involved in B[a]P activation in PLHC-1 cells. However, CYP1A induction causes only a relatively small increase in activation, probably because of the action of other enzymes involved in B[a]P activation and deactivation.
Ecological risk assessment in a large river-reservoir: 4. Piscivorous wildlife
Authors: Sample Bradley E , Suter Glenn W
Published: March 2010

Over 50 years of operations of facilities on the Oak Ridge Reservation (ORR), Tennessee, has resulted in the release of contaminants into the water, sediment, and biota of the Clinch River and Poplar Creek, downstream of the ORR. An iterative, weight-of-evidence approach was employed to assess risks these contaminants present to four piscivorous wildlife species (osprey [Pandion haliaetus], great blue heron [Ardea herodias], mink [Mustela vison], and river otter [Lutra canadensis]) in the Clinch River/Poplar Creek (CR/PC) watershed. Available data consisted of literature-derived NOAELs and LOAELs, field surveys, and toxicity tests. Contaminants of potential ecological concern (COPECs) were identified by comparing point estimates of exposure to NOAELs and included mercury and PCBs. Exposure to COPECs was reestimated using Monte Carlo methods, first at individual locations, then over ecologically relevant spatial scales. These exposure distributions were compared to LOAELs. Estimated exposure for mink was not sufficient to present a risk from any COPEC. Mercury and PCBs presented a significant risk to river otter at one location each. Exposure of osprey and great blue herons to mercury represented a significant risk at one and two locations, respectively. Field surveys of heron rookeries and osprey nests indicated no adverse effects on reproduction. Mink fed fish from the Clinch River displayed reduced reproduction only in the most contaminated of five toxicity test diets; this reduction was not statistically significant, however. The maximum mercury and PCB exposures estimated for mink along the Clinch River were significantly lower than the toxicity test exposures associated with adverse effects The weight of evidence indicates that contaminants from the ORR do not present a risk to mink, great blue heron, or osprey along the Clinch River; river otter, however, may be at risk from mercury and PCBs.
Modeling of residue stabilization
Authors: Velasco-Arjona Alfredo , Izquierdo Andrés , de Castro María Dolores Luque
Published: March 2010

A study was made on the decrease in toxicity of various contaminated residues when treated with three different stabilizers. General criteria of the requirements for stabilization were also established, which depended on both the toxicity and nature of the toxic substances. The modeling of the stabilization process will allow nonspecialized personnel to carry out the operations and will also standardize the modus operandi of such enterprises.
Effects of soil organic matter content and temperature on toxicity of dimethoate to Folsomia fimetaria (Collembola: Isotomiidae)
Authors: Martikainen Esko Anssi Tapio , Krogh Paul Henning
Published: March 2010

The purpose of these experiments was to study the effects of two major environmental factors, soil organic matter content (1.4–8.6%) and temperature (10–20°C), on chemical toxicity to a soil-dwelling collembolan Folsomia fimetaria. Dimethoate was used as a reference chemical. Effects on survival, reproduction, and juvenile size were investigated. Increasing soil organic matter content reduced toxicity significantly, but the differences disappeared when results were recalculated and expressed as soil pore-water concentrations. This supported the soil pore-water hypothesis. The effects of soil temperature were not so clear, because temperature affects not only the growth and reproduction of the collembolan but also the chemical degradation. In general, decreasing temperature seemed to increase toxic effects. The procedure for toxicity testing with F. fimetaria was further improved by using adults at stage 7 to 8, when males and females could reliably be distinguished by size. Furthermore, image processing was applied for the first time in the counting and size measurements of the collembolans.
Chromosomal aberrancy in white-footed mice (Peromyscus leucopus) collected on abandoned coal strip mines, Oklahoma, USA
Authors: Husby Michael P , Hausbeck John S , McBee Karen
Published: March 2010

This study was undertaken to determine the genetic consequences to small mammals of long-term exposure to heavy metal pollution. A secondary goal was to continue the process of validation of chromosomal aberration analysis as an in situ biological monitoring tool. During the spring, summer, and fall of 1992, white-footed mice (Peromyscus leucopus) were collected from four metal-polluted, abandoned coal strip mines and three uncontaminated reference sites in eastern Oklahoma, USA. Chromosomal aberrations were scored from standard bone marrow metaphase chromosome spreads. Seasonal differences were detected for aberrant cells (cells containing one or more chromosomal lesions) per individual (p = 0.0004), but there were no differences among sites or between sexes. Males and females were tested separately for lesions per individual, and neither sex showed a significant difference among sites but both showed seasonal differences across sites. Finally, a chi-square analysis showed that the difference between total lesions and aberrant cells was not significantly different among sites (p = 0.635), indicating that lesions were distributed among cells in approximately the same way among all sites.
Estrogenic potency of effluent from two sewage treatment works in the United Kingdom
Authors: Harries Jule E , Janbakhsh Afsaneh , Jobling Susan , Matthiessen Peter , Sumpter John P , Tyler Charles R
Published: March 2010

Rainbow trout were exposed for 3 weeks (in a flow-through system) to various dilutions of treated effluent (25, 50, 75, and 100%) from Harpenden and Chelmsford sewage treatment works (STW) during November 1994 and August 1996, respectively, and the induction of plasma vitellogenin was measured. Significant (p < 0.05) increases in plasma vitellogenin concentrations occurred in fish held in effluent from Harpenden STW at concentrations of 50% and above. At Chelmsford STW, the effluent appeared to be more potent, causing induction of vitellogenin in fish at concentrations as low as 25% (compared with 50% for the Harpenden effluent). Exposure to lower concentrations of effluent emanating from Chelmsford in April of the following year indicated that estrogenic activity was diluted to no-effect levels at this STW at concentrations between 12 and 25%.
Developmental toxicity of copper chloride, methylene chloride, and 6-aminonicotinamide to embryos of the grass shrimp Palaemonetes pugio
Authors: Rayburn James R , Fisher William S
Published: March 2010

Embryos of estuarine grass shrimp Palaemonetes pugio have demonstrated sensitivity to various solvents and petroleum products, indicating utility for evaluating estuarine contamination. Testing was performed to establish concentration-response curves for methylene chloride, copper chloride, and 6-aminonicotinamide, three known teratogenic chemicals. Two exposure periods were used, 4 d and 12 d, and both periods extended through hatching. The average 4-d LC50 values for methylene chloride, copper chloride, and 6-aminonicotinamide were 0.071% v/v, 1.82 mg/L, and 0.21 mg/ml, respectively. The average 12-d LC50 values for methylene chloride, copper chloride, and 6-aminonicotinamide were 0.031% v/v, 1.44 mg/L, and 0.057 mg/ml, respectively. Eye malformations were observed with embryos exposed to concentrations greater than 3 mg/L copper chloride or greater than 0.07% v/v methylene chloride. Very few abnormalities were observed in embryos exposed to 6-aminonicotinamide. Abnormal larval development was found with exposure to copper chloride at concentrations greater than 1 mg/L. The sensitivity and low variability found here further supports the development of these relatively simple methods using grass shrimp embryos. Establishment of sublethal developmental endpoints warrants further investigation because of their potential correspondence to mechanisms of toxic action.
Acute toxicity of the insecticides endosulfan, chlorpyrifos, and malathion to the epibenthic estuarine amphipod Gammarus palustris (Bousfield)
Authors: Leight Andrew K , Van Dolah Robert F
Published: March 2010

The acute effects of three commonly used pesticides were evaluated using the epibenthic, estuarine amphipod Gammarus palustris. This species is most abundant in intertidal salt marshes and has a cosmopolitan distribution. Laboratory bioassays were conducted under static and static-renewal conditions. Median lethal concentrations of endosulfan and chlorpyrifos were much lower at all exposure time points than malathion in the static exposures (e.g., 96-h LC50 = 0.43 μg/L for endosulfan, 0.30 μg/L for chlorpyrifos, and 4.65 μg/L for malathion). A similar pattern of toxicity was noted in the static-renewal exposures, with statistically significant differences in toxicity observed between the static versus static-renewal exposures for endosulfan at the 48-h time point, at none of the time points for chlorpyrifos, and at all three time points (48, 72, and 96 h) for malathion. The sensitivity of G. palustris was generally comparable to LC50 values found in the literature for other crustaceans, particularly for the 96-h exposures. Evaluation of field contaminant data, compared with the laboratory toxicity data, indicated that this species could serve as a useful bioindicator of contaminant stress in salt marsh habitats.
Do amphipods have the same concentration-response to contaminated sediment in situ as in vitro?
Authors: Dewitt Theodore H , Hickey Christopher W , Morrisey Donald J , Nipper Marion G , Roper David S , Williamson R Bruce , Dam Lawrence Van , Williams Erica K
Published: March 2010

An underlying assumption of laboratory-based toxicity tests is that the sensitivity of organisms in the laboratory (in vitro) is comparable to that in the field (in situ). We tested this assumption by exposing estuarine amphipods (Chaetocorophium cf. lucasi) to a concentration series of cadmium-spiked sediments in vitro and in situ for 10 d. In situ exposures were conducted within plastic-mesh cages on an intertidal mudflat. To characterize exposure, we measured interstitial water cadmium concentrations (IWCd), acid volatile sulfide (AVS), and simultaneously extracted Cd (SEMCd) at the beginning and end of the exposures. Between day 0 and day 10, AVS decreased in both in vitro and in situ exposures, while IWCd levels declined less in vitro (median 27%) than in situ (median 76%). Despite more extreme conditions of temperature (10–36°C) and salinity (18–22%o) in situ, in vitro and in situ exposures showed comparable survival responses based on SEMCd/AVS (LC50 [95% CI]: 1.6 [1.46–1.78] and 1.8 [1.76–1.83], respectively), with the onset of marked mortality above a SEMCd/AVS value of about one and minimal survival (<5%) above a value of two. Based on IWCd concentrations, however, sensitivity was significantly greater in vitro (LC50 = 0.41 μg Cd/L [0.171–0.959], in situ LC50 = 1.6 μg Cd/L [1.15–2.16]). We concluded that, in our tests, amphipod sensitivity in vitro was equal to or greater than its sensitivity in situ.
Toxicity of trifluoroacetate to aquatic organisms
Authors: Berends Albert G , Boutonnet Jean Charles , Rooij Christ G De , Thompson Roy S
Published: March 2010

As a result of the atmospheric degradation of several hydrofluorocarbons and hydrochlorofluorocarbons, trifluoroacetate (TFA) will be formed. Through precipitation, TFA will enter aquatic ecosystems. To evaluate the impact on the aquatic environment, an aquatic toxicity testing program was carried out with sodium trifluoroacetate (NaTFA). During acute toxicity tests, no effects of NaTFA on water fleas (Daphnia magna) and zebra fish (Danio rerio) were found at a concentration of 1,200 mg/L. A 7-d study with duckweed (Lemna gibba G3) revealed a NOEC of 300 mg/L. On the basis of the results of five toxicity tests with Selenastrum capricornutum, we determined a NOEC of 0.12 mg/L. However, algal toxicity tests with NaTFA and Chlorella vulgaris, Scenedesmus subspicatus, Chlamydomonas reinhardtii, Dunaliella tertiolecta, Euglena gracilis, Phaeodactylum tricornutum, Navicula pelliculosa, Skeletonema costatum, Anabaena flos-aquae, and Microcystis aeruginosa resulted in EC50 values that were all higher than 100 mg/L. The toxicity of TFA to S. capricornutum could be due to metabolic defluorination to monofluoroacetate (MFA), which is known to inhibit the citric acid cycle. A toxicity test with MFA and S. capricornutum revealed it to be about three orders of magnitude more toxic than TFA. However, a bioactivation study revealed that defluorination of TFA was less than 4%. On the other hand, S. capricornutum exposed to a toxic concentration of NaTFA showed a recovery of growth when citric acid was added, suggesting that TFA (or a metabolite of TFA) interferes with the citric acid cycle. A recovery of the growth of S. capricornutum was also found when TFA was removed from the test solutions. Therefore, TFA should be considered algistatic and not algicidic for S. capricornutum. On the basis of the combined results of the laboratory tests and a previously reported semi-field study, we can consider a TFA concentration of 0.10 mg/L as safe for the aquatic ecosystem.
Implications of gut purging for tissue residues determined in bioaccumulation testing of sediment with Lumbriculus variegatus
Authors: Mount David R , Dawson Timothy D , Burkhard Lawrence P
Published: March 2010

Bioaccumulation test procedures using the oligochaete Lumbriculus variegatus have been developed as a means of evaluating the accumulation of chemicals from freshwater sediments. To avoid including chemicals associated with gut contents as part of the measured tissue residue, a 24-h period of purging in clean water after the uptake phase of the test has been recommended. While purging acts to reduce bias from gut contents, it also has the potential to introduce bias caused by depuration of chemicals from tissues. In this paper, a series of model calculations are used to assess the expected sensitivity of measured residues of nonionic organic chemicals to the presence of sediment in the gut and to varying lengths of purging. If organisms are not purged, the predicted influence of gut contents on measured residue is not large (generally <20%) when a biota-sediment accumulation factor (BSAF) of one is assumed. However, if BSAFs substantially less than one apply, projected errors increase to 30-fold or more. To derive a better estimate of the time required for L. variegatus to clear the gut of sediment, a sediment purging experiment was conducted; results indicate that >98% of sediment had cleared the gut in 6 h (half-life = 0.98 h). Based on these results and model analyses, a much shorter purging period of 6 h, rather than 24 h, is suggested as a reasonable guideline for many test applications.
Facilitated transport in European soils from the Euro-soil project
Authors: Dolfing Jan , Scheltens Stieneke D
Published: March 2010

We studied the response of five reference soils from the European Union (a vertic cambisol, rendzina, dystric cambisol, orthic luvisol, and orthic podzol, also known as Euro-soils 1 to 5) to the addition of HCl and NaOH. For all soils, which were incubated as soil slurries, the amount of organic carbon in solution remained essentially constant upon addition of HCl but increased upon addition of NaOH; that is, it was not the pH of the soil that determined changes in the solubilization of dissolved organic carbon but ΔpH. This observation has implications for the design of active soil management strategies, because increased amounts of dissolved organic carbon in the soil solution pose a risk for leaching of contaminants to deeper soil layers and eventually to the groundwater. In the past, much attention has been paid to the reaction of soils to acidification and changing land use as practiced when agricultural land is taken out of production. The observations reported here indicate that soil alkalization is not necessarily without environmental and toxicological risks.
Reproductive ecology of tree swallows (Tachycineta bicolor) with high levels of polychlorinated biphenyl contamination
Authors: McCarty John P , Secord Anne L
Published: March 2010

Tree swallows (Tachycineta bicolor) breeding along the Hudson River forage extensively on PCB-contaminated insects that emerge from the river. We studied the reproductive ecology and behavior of tree swallows breeding at several sites along the Hudson River. Related work has shown that PCB levels in both eggs and chicks were among the highest ever reported in this species, with concentrations comparable to those found in aquatic organisms in the Hudson River. In 1994, reproductive success at PCB-contaminated sites was significantly impaired relative to other sites in New York. Reduced reproductive success was largely due to high levels of nest abandonment during incubation and reduced hatchability of eggs. In 1995, reproductive output was normal, but higher than expected rates of abandonment and supernormal clutches persisted. Growth and development of nestlings was not significantly impaired. Given the levels of contamination in this population, the success of most Hudson River tree swallows reinforces the importance of understanding interspecific differences in the effects of contaminants.
Individual and demographic responses of the gray-tailed vole to vinclozolin
Authors: Caslin Tracie M , Wolff Jerry O
Published: March 2010

We tested the hypothesis that vinclozolin, a fungicide that has been demonstrated in the laboratory to disrupt hormonal activity of rats and mice, would have adverse effects on a field population of voles. We conducted two field experiments to determine whether exposure to vinclozolin following a standard application rate of Curalanr̀ fungicide had adverse effects on the reproductive development and demography of the gray-tailed vole, Microtus canicaudus. In one experiment conducted during the rainy season, mean lengths of testes and seminal vesicles were smaller (p ≤ 0.08), levels of plasma testosterone were lower (p = 0.025), and proportion of pregnant females was lower (p = 0.05) in treatment than in control animals; however, this difference was not sufficient to affect juvenile recruitment, sex ratio, or population growth. In a second experiment conducted under drier conditions, no differences occurred in measurements of reproductive organs or demography of treatment and control populations. The results suggest that precipitation may have increased the potency of the chemical by washing it down to ground level and (or) by increasing the uptake of toxic metabolites by the plants, resulting in greater dietary exposure to the voles. Although our results revealed no biologically significant effects of vinclozolin at the population level under the conditions of our experiments, they do suggest that multiple applications or a higher application rate of a vinclozolin product may have negative effects on male reproductive development and demography in wild populations.
Ecotoxicological and analytical assessment of hydrocarbon-contaminated soils and application to ecological risk assessment
Authors: Saterbak Ann , Toy Robin J , Wong Diana C L , McMain Bruce J , Williams M Patty , Dorn Philip B , Brzuzy Louis P , Chai Eric Y , Salanitro Joseph P
Published: March 2010

Ecotoxicological assessments of contaminated soil aim to understand the effect of introduced chemicals on the soil flora and fauna. Ecotoxicity test methods were developed and conducted on hydrocarbon-contaminated soils (<5,000–30,000 mg/kg total petroleum hydrocarbon) and on adjacent uncontaminated control soils from eight field locations. Tests included 7-d, 14-d, and chronic survival tests and reproduction assays for the earthworm (Eisenia fetida) and seed germination, root length, and plant growth assays for corn, lettuce, mustard, and wheat. Species-specific responses were observed with no-observed effect concentrations (NOECs) ranging from <1 to 100% contaminated soil. The 14-d earthworm survival NOEC was equal to or greater than the reproduction NOEC values for numbers of cocoons and juveniles, which were similar to one another. Cocoon and juvenile production varied among the control soils. Germination and root length NOECs for mustard and lettuce were less than NOECs for corn and wheat. Root length NOECs were similar to or less than seed germination NOECs. Statistically significant correlations (p < 0.05) for earthworm survival and seed germination as a function of hydrocarbon measurements were found. The 14-d earthworm survival and the seed germination tests are recommended for use in the context of a risk-based framework for the ecological assessment of contaminated sites.
Two-region linear/nonlinear sorption modeling: Batch and column experiments
Authors: Young Dirk F , Ball William P
Published: March 2010

Batch and column experiments were conducted to assist in elucidation of the mechanism and rates of slow diffusion of 1,2,4-trichlorobenzene into Borden sand. Batch rate experiments were conducted at three concentration levels, and a full isotherm was developed over 550 d. The equilibrium isotherm showed significant nonlinearity (Freundlich exponent = 0.75). Three column experiments were conducted—two at low velocity (each at a different input concentration) and one at high velocity. The data were analyzed with four different models; the two most successful are described in detail here. These two models divided sorption between instantaneously equilibrating and diffusion-limited domains, with either a linear or nonlinear sorption isotherm assumed for the instantaneously equilibrating fraction of sorption sites. Either model could simulate any single data set by adjustment of two parameters; however, no single parameter set could simulate all data sets. The model with a linearly sorbing instantaneous fraction described the batch data better than the model with a nonlinearly sorbing instantaneous fraction; however, a nonlinearly sorbing instantaneous fraction described the slow column experiments much better than a linearly sorbing instantaneous fraction. The high-flow-rate column experiment indicated that the assumed instantaneous fraction is actually influenced by rate limitations, suggesting that more complex models are needed in order to simulate this shorter time scale behavior. Overall, our work illustrates how one needs to include a wide variety of experimental conditions in order to fully test the complex set of sorption equilibrium and rate mechanisms that are present in natural solids.
Survey of estrogenic activity in United Kingdom estuarine and coastal waters and its effects on gonadal development of the flounder Platichthys flesus
Authors: Allen Yvonne , Scott Alexander P , Matthiessen Peter , Haworth Sarah , Thain John E , Feist Steve
Published: March 2010

Estrogenic discharges are known or suspected to be present in many United Kingdom estuaries and are also occurring from offshore oil and gas installations. The aim of this study was to establish whether estrogens and their mimics are present in marine waters at concentrations that can produce biological responses in fish and, if so, to discover whether the effects are likely to be harmful to populations and communities through changes in reproductive and other physiological processes. Laboratory studies and extensive field surveys were carried out with the euryhaline flounder (Platichthys flesus), using the amount of yolk protein vitellogenin in the blood of free-living male fish as an indicator of exposure to estrogens. Exposure to the synthetic estrogen ethynylestradiol for 3 weeks confirmed that the vitellogenin response was made and showed that this species is about one order of magnitude less sensitive than the freshwater species rainbow trout. The fish did not respond to the estrogen mimic nonylphenol at concentrations of 30 μg/L. Wild male flounder were sampled from four contaminated United Kingdom estuaries: the Tyne, Crouch, Thames, and Mersey. Fish from one or more sites in each estuary had significantly elevated concentrations of vitellogenin in their blood when compared to concentrations in fish from the clean control estuary (Alde River). Vitellogenin concentrations in the Tyne and Mersey fish were four and six orders of magnitude greater, respectively, than control concentrations. Elevated vitellogenin concentrations were also seen in some male flounder caught in coastal areas. Approximately 20% of male fish from the Mersey estuary contained oocytes in their testes, but this intersex condition was not seen elsewhere. The implications of these findings for fish populations are discussed.
Organic chloramines in disinfected wastewaters: Rates of reduction by sulfite and toxicity
Authors: Jameel Rubina H , Helz George R
Published: March 2010

Peptides and protein fragments that have been monochlorinated at terminal amino-N sites are known to react sluggishly with S(IV) dechlorinating agents in wastewater treatment plants. Persistence of these chloramines may imperil downstream aquatic organisms. Reactivity of sidechain amino-N is explored in this paper, and previous kinetic information on chloramine reduction by S(IV) is summarized. Much like other chloramines, side-chain chlorinated N-chloroacetyllysine reacts with SO1/2- in borate buffer at 25°C according to the law rate = [SO2−3 [chloramine](520[H3BO3] + 5.7 × 1010[H3O+] + 4.1) (time in s, concentration in M). Apparently because of their greater basicity, aliphatic monochloramines such as Nchloroacetyllysine are reduced rapidly at near-neutral pH, in contrast to terminally chlorinated peptides. At pH > 10, all monochloramines will be reduced at nearly the same, quite slow rate (t1/2 ≈ 0.1/[SO2−3]; time in s, SO2−3 in M). Microtox™ (Azur Environmental, Carlsbad, CA, USA) bioassays indicate that two terminally chlorinated N-chloropeptides as well as side-chain chlorinated N-chloroacetyllysine are much less toxic to Vibrio fisheri than NH2Cl, N-chloroglycine, and N-chloropiperidine. An astonishingly simple relationship describes the bioassay results at 5 min exposure as In(EC50) = −3.684 + 0.0221 (MW) (EC50 in mg/L as C12; molecular weight [MW] in Daltons). These exploratory data offer a basis for optimism that S(IV)-surviving N-chloropeptides will prove less toxic in natural ecosystems than rapidly reduced chloramines, but further investigations are needed.
Applicability of Tedlar™ bags to aqueous sampling for ambient toxicity testing: Adsorption of trace metals
Authors: deBruyn Adrian M H , Rasmussen Joseph B
Published: March 2010

Many materials commonly used to collect and store samples for ambient toxicity testing will readily sorb and/or leach contaminants. Previous work indicates that Tedlar™ (polyvinylfluoride) sampling bags are largely inert toward organics; we report here that this material is similarly inert to Co2+, Cu2+, Zn2+, Sb3+, Pb2+, and Cd2+ in neutral solution. We found no trace metal adsorption at low pH and only slight adsorption (mean loss = 2.1 ppb) at neutral pH from 100-ppb solutions held in Tedlar bags for 24 h.
Subcellular distribution and translocation of radionuclides in plants
Authors: Gouthu Satyanarayana , Weginwar Rajiv , Arie Tsutomu , Ambe Shizuko , Ozaki Takuo , Enomoto Shuichi , Ambe Fumitoshi , Yamaguchi Isamu
Published: March 2010

The subcellular distribution of radionuclides in Glycine max Merr. (soybean) and Cucumis sativus L. (cucumber) and translocation of plant absorbed radionuclides with growth in soybean were studied. More than 60% of cellular incorporated Rb, Sr, Mn, Co, Nb, and Se remained in the supernatant fraction; 55% and 20% of Cr was bound to soybean and cucumber cell wall fractions, respectively; 70% or more of Be, Y, and Fe was fixed in the chloroplast fraction; and approx. 10% of Sc, Fe, V, and As were fixed in the mitochondrial fraction. Translocation of nuclides within the soybean plant at different stages of growth has been determined. Vanadium, Y, Be, Se, Nb, Sc, Cr, and Zr were predominantly accumulated in the root. Although the total percentage of plant uptake of Sc, Zr, Nb, and Cr was high, because of low mobility and translocation to shoot, their accumulation in the fruit fraction was negligible. The translocation of mobile nuclides in plants was demonstrated clearly by Rb, Zn, and Fe. Data on the nuclide fraction mobilized from vegetative parts into edible parts was used to assess the percentage of accumulated radionuclides in plants that may reach humans through beans.
Accumulation and effects of aluminum smelter—generated polycyclic aromatic hydrocarbons on soft—bottom invertebrates and fish
Authors: NÆae, Kristoffer , Hylland Ketil , Oug Eivind , Föourlin Lars , Ericson Gunilla
Published: March 2010

An integrated study involving measurements of polycyclic aromatic hydrocarbon (PAH) levels in bottom sediments, assessments of resident soft—bottom communities, the accumulation of PAHs in soft—bottom invertebrates, and biomarker responses in invertebrates and fish was conducted to assess the impact of an aluminum reduction plant in a Norwegian fjord. The fjord sediments were heavily contaminated by PAHs in the inner reaches near the aluminum smelter, where concentrations were well above levels elsewhere reported to induce biological effects. Nevertheless, the PAH contamination in the fjord did not seem to have severe effects on the benthic biota. This conclusion can be drawn from the soft—bottom communities as well as from biomarker analyses. Presumably, contaminant speciation is important for explaining the restricted biological effects. The results support the assumption that PAHs associated with soot—like structures have limited bioavailability. They also point to the need to link various single—species approaches to measurements of effects on higher levels of organization and with an understanding of the speciation of the chemical contaminant.
Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (river Lot, France): II. Metallothionein response to metal exposure
Authors: Baudrimont Magalie , Andrès Sandrine , Metivaud Jacqueline , Lapaquellerie Yvon , Ribeyre Francis , Maillet Noelle , Latouche Claude , Boudou Alain
Published: March 2010

Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic pollution gradient in the river Lot, France, downstream from an old Zn ore treatment facility (see Part I). From April to September 1996, we studied Cd and Zn bioaccumulation and the metallothionein-like metal-binding protein (MT) concentrations by subsampling the cages at t = 0, 21, 49, 85, 120, and 150 d. Marked differences were observed among the four stations. At the most polluted station Riou-Mort, MT concentrations did not increase despite very rapid metal accumulation; all mollusks died between days 49 and 85, suggesting that the metal detoxification mechanisms were overwhelmed at this station. At the next station downstream, the final levels of bioaccumulated metal after 150 d were as high as those at the Riou-Mort station (t = 21 d), but in this case the MT concentrations also increased progressively with positive correlations between MT and metal concentrations; no mortality was observed, but a significant growth inhibition was revealed in comparison to the reference site, with a lack of correlation between MT (as a stress response) and reduced growth. Subcellular metal partitioning, as determined by size-exclusion chromatography, revealed that most of the Cd was sequestered by MT (70% of cytosolic Cd). In contrast, most of the Zn was bound to low molecular weight proteins (70%, ≤ 6.5 kD), the MT fraction representing only 12% of cytosolic Zn. These data show the marked role of MT toward Cd bioaccumulation and toxic effects on this freshwater bivalve species.
Biological implications of sulfide in sediment—a review focusing on sediment toxicity
Authors: Wang Feiyue , Chapman Peter M
Published: March 2010

The biological implications of sulfide in sediment are poorly understood and all too often ignored despite the fact that sulfide can be extremely important in determining sediment toxicity to resident biota. Sulfide influences sediment toxicity in three major ways, which are reviewed in detail: as a toxicant in its own right; by reducing metal toxicity by forming insoluble metal sulfide solids and/or by forming metal sulfide complexes; and by affecting animal behavior, which in turn can alter the toxicity of not just the sulfide but also other sediment contaminants. Our present limited understanding of sulfide in sediments represents two major problems related to determining the toxicity of sediments, both in the laboratory and the field, and the causative agents of such toxicity. First, we do not know how important sulfide toxicity is to resident populations. Second, by not adequately considering sulfide toxicity, we risk underestimating toxicity and misidentifying the causative agents. Generic and specific recommendations related to resolving these problems are provided, including appropriate measurement and monitoring of sulfide in the laboratory and the field, determination of toxicity thresholds and tolerances for a wide range of sediment-dwelling organisms, further development of toxicity identification evaluation procedures, further research into sulfide effects on metal toxicity, and determination of the influence of sulfide on bioirrigation.
Hydrolysis of tert-butyl formate: Kinetics, products, and implications for the environmental impact of methyl tert-butyl ether
Authors: Church Clinton D , Pankow James F , Tratnyek Paul G
Published: March 2010

Asessing the environmental fate of methyl tert-butyl ether (MTBE) has become a subject of renewed interest because of the large quantities of this compound that are being used as an oxygenated additive in gasoline. Various studies on the fate of MTBE have shown that it can be degraded to tert-butyl formate (TBF), particularly in the atmosphere. Although it is generally recognized that TBF is subject to hydrolysis, the kinetics and products of this reaction under environmentally relevant conditions have not been described previously. In this study, we determined the kinetics of TBF hydrolysis as a function of pH and temperature. Over the pH range of 5 to 7, the neutral hydrolysis pathway predominates, with kN = (1.0 ± 0.2) × 10−6/s. Outside this range, strong pH effects were observed because of acidic and basic hydrolyses, from which we determined that kA = (2.7 ± 0.5) × 10−3/(M·s) and kB = 1.7 ± 0.3/(M·s). Buffered and unbuffered systems gave the same hydrolysis rates for a given pH, indicating that buffer catalysis was not significant under the conditions tested. The activation energies corresponding to kN, kA, and kB were determined to be 78 ± 5, 59 ± 4, and 88 ±11 kJ/mol, respectively. In all experiments, tert-butyl alcohol was found at concentrations corresponding to stoichiometric formation from TBF. Based on our kinetics data, the expected half-life for hydrolysis of TBF at pH = 2 and 4°C (as per some standard preservation protocols for water sampling) is 6 h. At neutral pH and 22°C, the estimated half-life is 5 d, and at pH = 11 and 22°C, the value is only 8 min.
Effects of a pulsed treatment with the herbicide afalon (active ingredient linuron) on macrophyte-dominated mesocosms. I. Responses of ecosystem metabolism
Authors: Kersting Kees , Van Wijngaarden René P.A.
Published: March 2010

Experimental drainage ditches used as mesocosms were treated with linuron three times, at 4-week intervals, at nominal concentrations of 0, 0.5, 5, 15, and 50 μg/L. After each treatment, the mesocosms were kept static for 1 week. They were then flushed with noncontaminated surface water, with a residence time of 5 d, until the next treatment. Structural and functional measurements were made. A companion paper discusses the structural aspects. Dissolved oxygen concentrations and pH were measured continuously at 15-min intervals. Both variables declined during the static periods, and a lowest-observed-effect concentration (LOEC) of 5 μg/L was noted for both response variables. All mesocosms recovered during the flushing periods. Diurnal oxygen curves were used to calculate ecosystem gross primary production (GPP) and ecosystem oxygen consumption. Ecosystem oxygen consumption was not affected by the linuron treatments, but GPP had an EC50 of 21 μg/L during the static period after the first treatment. The EC50 for GPP increased to 36 μg/L after the second treatment and to 80 μg/L after the third treatment. This increase in EC50 is interpreted as an adaptation of the ecosystem, the mechanism of which could not be identified. The LOEC was 15 μg/L for all treatments and did not change over time. Between treatments, GPP recovered to the level of the controls. The LOEC for the long-term GPP was 50 μg/L.
What is the relationship between whole effluent toxicity and instream biological condition?
Authors: Diamond Jerome , Daley Christiana
Published: March 2010

We compileda data base of 250 dischargers across the United States and examined relationships between standardized Ceriodaphnia dubia and Pimephales promelas (fathead minnows), whole effluent toxicity (WET) test endpoints, and instream biological condition as measured by benthic macroinvertebrate assessments. Sites were included in the analysis if the effluents were not manipulated before testing (e.g., dechlorination), and standardized biological and physical habitat assessment methods were used upstream and directly downstream of the discharge. Several analyses indicated that fish endpoints were more related to instream biological condition than Ceriodaphnia WET endpoints. Dischargers that failed <25% of their tests had ≤15% chance of exhibiting instream impairment. Effluent dilution was the strongest factor affecting relationships between WET and observed biological conditions. Effluents that comprised >80% of the stream under low-flow conditions exhibited better relationships between WET and instream condition than effluents with greater dilution. Effluents that comprised <20% of the stream had a low probability of exhibiting impairment, even if several WET test failures were observed over a 1-year period. Fish acute and chronic WET information could predict instream biological conditions; however, WET compliance, based on 7Q10 stream flow, was consistently conservative. Our results indicate that WET was more predictive of instream biological condition if several tests were conducted, more than one type of test was conducted, and endpoints within a test were relatively consistent over time.
Uncertainty analysis for an equilibrium partitioning-based estimator of polynuclear aromatic hydrocarbon bioaccumulation potential in sediments
Authors: Clarke Joan U , McFarland Victor A
Published: March 2010

In regulatory evaluations of contaminated sediments, an equilibrium partitioning-based screening test called theoretical bioaccumulation potential (TBP) is often performed to estimate the probable concentrations of neutral organic contaminants that would eventually accumulate in aquatic organisms from continuous exposure to a sediment. The TBP is calculated from contaminant concentration and organic carbon content of the sediment, lipid content of target organisms, and a partition coefficient, usually the biota-sediment accumulation factor (BSAF). However, routine applications of TBP have not included analysis of uncertainty. This paper demonstrates two methods for uncertainty analysis of TBP: a computational method that incorporates random and systematic error and a simulation method using bootstrap resampling of replicated model input parameters to calculate statistical uncertainty measures. For prediction of polynuclear aromatic hydrocarbon (PAH) bioaccumulation in bivalves exposed to contaminated sediments, uncertainty as a factor of TBP ranged from 1.2 to 4.8 using the computational method and 0.5 to 1.9 based on bootstrap 95% confidence intervals. Sensitivity analysis indicated that BSAF parameters, especially tissue contaminant concentration and lipid content, contributed most to TBP uncertainty. In bootstrap tests of significance, TBP significantly over- or underestimated actual PAH bioaccumulation in bivalves in 41% and 10% of comparisons, respectively.
Multiple computer-automated structure evaluation study of aquatic toxicity II. Fathead minnow
Authors: Klopman Gilles , Saiakhov Roustem , Rosenkranz Herbert S
Published: March 2010

An acute toxicity model was constructed on the basis of experimental data for 685 chemicals tested for toxicity for fathead minnow. The multiple computer-automated structure evaluation (M-CASE) program was used for the construction of the model. Based on a comparison between our results and published results, we found that the methodology is able to describe acute toxicity for the fathead minnow with high accuracy. The model incorporates the concept of a baseline activity as one of the parameters for the correlation as well as others parameters such as the presence of biophores, hardness-softness parameters, and other characteristics determined from quantum mechanical calculations. By using its artificial intelligence algorithm, M-CASE chooses automatically the most suitable set of parameters for evaluating the minnow toxicity of any organic molecule. We found that M-CASE can correctly predict acute toxicity for minnow for 80% of organic compounds with an average error of only 0.4 log units of lethal dose. The main toxicophores, corresponding to polar narcosis and to other types of reactive chemicals, were identified.