bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the toxicity of metals in soils amended with sewage sludge using a chemical speciation technique and alux-based biosensor
Authors: McGrath Steve P , Knight Bruce , Killham Ken , Preston Sara , Paton Graeme I
Published: March 2010

Currently, regulations regarding the maximum permitted concentrations of metals in soils are based on measurements of the total concentration. However, a range of chemical and biological techniques are being developed to predict the bioavailable component of these pollutants. A lux-based biosensor was tested in soil solutions extracted from two field experiments at Braunschweig, Germany, that had the same metal inputs, but differed in pH. The bioluminescence response was found to decline as the free Zn2+ increased, and both soils fitted the same relationship with soil solution metal concentrations. The EC25 and EC50 derived from this curve were 1.9 and 6.1 mg/L, respectively. In contrast, the response to total Zn concentrations in the bulk soil showed distinct curves for each soil, further highlighting the appropriateness of free Zn2+ as a toxicity indicator. Other metals were present in the soil, but were unlikely to be toxic, because the observed concentrations were less than their individual toxic threshold values in solution. Bioluminescence-based biosensors were concluded to possibly offer an inexpensive and rapid technique to evaluate the bioavailability of metals in soil systems. The response of these biosensors can be related to soil solution speciation measurements, and this gives a common basis for expression of toxic thresholds in different soils.
Cholinesterase inhibition in tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) exposed to organophosphorus insecticides in apple orchards in Ontario, Canada
Authors: Burgess Neil M , Hunt Katherine A , Bishop Christine , Weseloh D V (Chip)
Published: March 2010

Apple orchards occupy approximately 12,565 ha of land in Ontario, Canada, and are treated with the greatest number and applications of pesticides among all agricultural crops within the province. The potential for exposure to wildlife from frequent organophosphorus (OP) spray applications is therefore considerable. This study investigated the impact of agricultural spray applications of azinphos-methyl, diazinon, phosalone, and phosmet in apple orchards on the cholinesterase (ChE) activity of wild birds nesting in orchards. These four OP pesticides ranked among the most widely used insecticides used on all fruit crops in Ontario in 1988. Tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) were chosen as monitor species because they commonly breed and forage within apple orchards, utilize different feeding strategies, and are readily attracted to nest boxes. Brain and plasma ChE activities were determined for nestling bluebirds and swallows, and plasma ChE was measured in adult swallows for comparison with nestling data. In adult tree swallows, mean plasma ChE levels were significantly inhibited 41% compared to controls 12 h after a second application of azinphos-methyl. Mean plasma ChE activity in another group of adult tree swallows dropped by 21 and 19% following a multiple phosmet application. In nestlings, brain ChE activities obtained postspray often fell below predicted activities calculated from control siblings. This trend was especially apparent in the younger nestlings, less than 6 d old. However, for bluebirds the rates of increase of brain ChE with age in nestlings from treated sites was significantly lower than in nestlings from control sites. Brain ChE activity of two nestlings found dead following a phosalone application gave no indication that insecticide exposure was responsible. No other dead or moribund birds were discovered during the course of the study. Sequential plasma sampling of siblings, before and after OP application, was beneficial in reducing the required number of nests sampled by one half, but plasma ChE was less reliable overall than brain ChE in indicating exposure. Results of depressed ChE levels in tree swallows and eastern bluebirds inhabiting apple orchards are consistent with avian species in other orchard monitoring studies. No indication was found that OP exposure due to agricultural spraying in apple orchards adversely affected the survival of the birds we monitored.
Biomarkers of exposure of brown bullheads (Ameiurus nebulosus) to contaminants in the lower Great Lakes, North America
Authors: Arcand-Hoy Lisa D , Metcalfe Chris D
Published: March 2010

Brown bullheads (Ameiurus nebulosus) from three contaminated sites (Detroit River, Hamilton Harbour, and Black River) and two relatively clean reference sites (Old Woman Creek and Bay of Quinte) in the lower Great Lakes were monitored for several biomarkers of exposure to chemical contaminants. Bullheads from the contaminated sites had elevated hepatosomatic indices, increased ethoxyresorufin-O-deethylase (EROD) activity, decreased hepatic retinoid stores, and a greater incidence of hepatic neoplasms. Fluorescent aromatic compounds (FACs) in the bile were also elevated in bullheads from the Black River and Hamilton Harbour in comparison to fish from reference sites. A correlation was found between reduction of hepatic retinoid stores and induction of hepatic EROD activity in bullheads. Principal component analysis of biomarker data demonstrated that biomarker patterns in Detroit River bullheads were different from those of Black River and Hamilton Harbour bullheads. Biomarkers in fish are useful monitoring tools for detecting contamination of the aquatic environment, but interpretation of results is limited by within-and between-site variability in the responses, some of which may be explained by mobility of the fish. In contaminated areas, bile fluorescent aromatic compounds appear to be the best indicator of recent exposure to polynuclear aromatic hydrocarbons, whereas responses to other biochemical biomarkers (e.g., EROD and retinoids) appear to be over a longer time period.
Fluorescent aromatic hydrocarbons in bile as a biomarker of exposure of brown bullheads (Ameiurus nebulosus) to contaminated sediments
Authors: Leadly Todd A , Arcand-Hoy Lisa D , Haffner G Doug , Metcalfe Chris D
Published: March 2010

Analysis of fluorescent aromatic compounds (FACs) in the bile of fish has been widely used as a biomarker of exposure to polynuclear aromatic hydrocarbon (PAH) contamination. However, bile FAC data for feral fish populations are typically highly variable, and in a few cases, elevation of FACs has not been observed in fish from contaminated areas. In this study, the bile FACs and hepatic ethoxyresorufin-O-deethylase activity in brown bullheads (Ameiurus nebulosus) exposed in the laboratory to contaminated sediments from Hamilton Harbour, Ontario, Canada, increased by 173-fold within 72 h of initial exposure and rapidly declined thereafter. In bullheads caged in the contaminated Trenton Channel area of the Detroit River, bile FACs also increased rapidly within 4 d of initial exposure to mean levels >3,000 ng of benzo[a]pyrene equivalents per milliliter of bile. Surprisingly, there was no difference in the mean-levels of bile FACs in fish caged above the sediment versus fish caged in direct contact with the sediment, indicating that water may be the major vector for uptake of PAHs. The lower bile FACs in bullheads caged in other regions of the Detroit River were consistent with the lower concentrations of PAHs in the sediments from these areas. These data indicate that bile FAC levels are a biomarker of recent exposure to aromatic hydrocarbons in sediments. However, FAC data were highly variable even in these studies, in which fish were relatively homogeneous in size, feeding status, and exposure history. Therefore, even higher variability in bile FAC data are expected in biomarker studies as a result of differences in reproductive status, size, diet, and mobility of the fish.
Effect of sediment type, feeding level, and larval density on growth and development of a midge (Chironomus riparius)
Authors: Ristola Tiina , Pellinen Jukka , Ruokolainen Minna , Kostamo Auli , Kukkonen Jussi V K
Published: March 2010

A 10-d growth test and an emergence test were performed with Chironomus riparius Meigen in four unpolluted lake sediments (organic carbon content 0.5–57%) using different feeding levels (Tetramin® at 0.03, 0.06, 0.12, or 0.33 mg/larva/d in the growth test and 0, 0.15, or 0.30 mg/larva/d in the emergence test) to study how sediment type and feeding level affect larval growth. To examine effects of larval density on growth, another growth test was performed using densities of one larva per 24, 12, 4.8, or 2.4 cm2 and a feeding level of Tetramin at 0.12 mg/larva/d. Regardless of sediment type, feeding was necessary in the experiments started with first-instar larvae. The effects of sediment physicochemical characteristics on larval growth and development could not be totally compensated for by food addition. When fed, larvae grew best in sandy sediment with low organic carbon content (0.5%). Acceptable survival was achieved with a very low food dose (0.03 mg/larva/d), but a somewhat higher dose (0.12 mg/larva/d) is recommended. Increment of feeding accelerated larval growth and development. Larval growth was correlated to the food dose per individual and to the density of food particles on the sediment surface.
Priority setting for existing chemicals: European Union risk ranking method
Authors: Hansen Bjorn G , van Haelst Anniek G , van Leeuwen Kees , van der Zandt Peter
Published: March 2010

In order to provide a legal framework within the European Union (EU) for the evaluation of existing chemicals (i.e., substances listed in the European Inventory of Existing Commercial Substances), Council Regulation (EEC) 793/93 was adopted, in which the evaluation of the existing chemicals is carried out by four steps, namely data collection, priority setting, risk assessment, and, if necessary, risk reduction. To fulfill the priority-setting step the EU Risk Ranking Method (EURAM) was developed to produce rankings that are the basis for drawing up lists of substances, used for priority setting, among the so-called high production volume chemicals appearing in the International Uniform Chemical Information database. The EURAM ranks substances on the basis of their potential risk to humans and the environment by using a simple exposure-effect model, containing both human health and environmental effect endpoints as well as exposure parameters. The EURAM fulfills criteria for a good chemical ranking scheme and has been applied and used as a basis for selecting substances for the second and the third list of priority substances as foreseen under Council Regulation (EEC) 793/93.
Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures
Authors: Swartz Richard C
Published: March 2010

Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges—low and—median, equilibrium partitioning concentrations, apparent effects threshold, ΣPAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the effects of mixtures. Polycyclic aromatic hydrocarbons virtually always occur in field-collected sediment as a complex mixture of covarying compounds. When expressed as a mixture concentration, that is, total PAH (TPAH), the guidelines form three clusters that were intended in their original derivations to represent threshold (TEC = 290 μg/g organic carbon [OC]), median (MEC = 1,800 μg/g OC), and extreme (EEC = 10,000 μg/g OC) effects concentrations. The TEC/MEC/EEC consensus guidelines provide a unifying synthesis of other SQGs, reflect causal rather than correlative effects, account for mixtures, and predict sediment toxicity and benthic community perturbations at sites of PAH contamination. The TEC offers the most useful SQG because PAH mixtures are unlikely to cause adverse effects on benthic ecosystems below the TEC.
Life-cycle framework for assessment of site remediation options: Method and generic survey
Authors: Diamond Mriam L , Page Cynthia A , Campbell Monica , McKenna Stephen , Lall Ronald
Published: March 2010

To address burdens associated with contaminated sites and issuing from remediation activities, a life-cycle framework (LCF) was developed, including an approach based on life-cycle management (LCM) and an adaptation of life-cycle assessment (LCA). Intended for application to a wide range of remediation options, the objective of the LCF is to broaden consideration of potential impacts beyond the contaminated site and over a prolonged time frame. The LCM approach is a qualitative method for investigating remediation activities from a life-cycle perspective. This adaptation of the more rigorous, quantitative LCA method has involved specifying appropriate life-cycle stages, a long-term time horizon, a spatial boundary encompassing the contaminated site and other affected locations, a process boundary containing the contaminated soil, and an impact assessment method that considers site- and process-related metrics. To assess the suitability of LCM as a decision-making tool, six generic site remediation options were investigated: no action, encapsulation, excavation and disposal, vapor extraction, in situ bioremediation, and soil washing. The analysis exemplified tradeoffs between the streamlined LCM, and comprehensive, quantitative LCA approaches, and highlighted potential environmental and human health impacts arising from the six technologies investigated.
Silicone-based polymers as oil spill treatment agents
Authors: Pelletier Éamilien , Siron Robert
Published: March 2010

A new family of oil-treatment agents was prepared by reacting polyoxyethylenic surfactants, alkyl alcohols, or carboxylic acids with alkylchlorosilanes in light hydrocarbon solvents. The treating solutions undergo rapid hydrolysis upon contact with the water surface and the reaction products can encapsulate and solidify oil slicks and other floating hydrocarbons. The removal of the resulting silicone—oil residues from the water surface can be performed by simple netting. Residues can be treated by washing with dichloromethane, leaving inert silicone polymers to be discarded and chemically unaltered hydrocarbons to be recycled. The noteworthy advantages in favor of these new oil-treating agents are the ease of synthesis using readily available chemicals, the very low environmental toxicity of silicones, the efficiency of the agents to solidify oil at a high oil to agent ratio, and the ease of recycling of the oil—silicone residues. Silicone treating agents could find their place in the toolbox of oil spill fighters in response to small accidental and intentional spills occurring frequently in marinas, harbors, along recreational beaches, navigation canals, industrial sites, or along highways. The practical problems to be addressed before any attempt at commercialization of these compounds are the use of highly flammable light hydrocarbons as carrier solvents, the production of corrosive HCl during the hydrolysis process, and the relatively high water content of silicone—oil residues to be recycled.
Fate of a new silicone-based oil-treating agent and its effects on marine microbial communities
Authors: Padrós Jaime , Pelletier Émilien , Siron Robert , Delille Daniel
Published: March 2010

A new silicone-based agent was developed to treat and recover oil slicks and various floating oily residues that are often observed in marinas and harbors. As part of its ecotoxicologic assessment, the fate of the treating agent alone or combined with crude oil, and the effects on natural microbial communities were studied in estuarine mesocosms (3.5 m3) over a 9-week period. The ability of the in situ formed silicone layer to trap an oil slick at the water surface was highlighted by a significative reduction in the volatilization, natural dispersion, and sedimentation of the treated oil. The treatment favored the dissolution of light aromatic hydrocarbons such as methyl-naphthalenes but these compounds were rapidly biodegraded in the water column. The agent alone, as well as the treated or untreated oil, had no effect on the biomass and photosynthetic ability of the phytoplankton community entrapped in the mesocosms. A significant stimulation of oil-degrading bacteria was noted in mesocosms containing treated and untreated oil slicks. On the basis of these results, we conclude that the use of a silicone-based treating agent could be an effective countermeasure to an oil spill, with neither deleterious effects to natural microbial communities nor to long-term biodegradation of the unrecovered oil residues.
Effect of kinetics of complexation by humic acid on toxicity of copper to Ceriodaphnia dubia
Authors: Ma Huizhong , Kim Sang Don , Cha Daniel K , Allen Herbert E
Published: March 2010

The rate of reaction of trace metal ions is an important consideration when studying the chemistry of trace metals in natural waters. The application of speciation models to natural water systems requires knowledge of kinetics if reactions are slow. Most bioassay and toxicity tests conducted in static and flow-through systems have not taken reaction kinetics into account. Therefore, results from these studies may overestimate the toxicity in the receiving waters. In the present study, the kinetics of the interaction of Cu(II) with humic acid (HA) and its influence on the toxicity of copper to Ceriodaphnia dubia were investigated by both chemical kinetic studies using a copper ion selective electrode and bioassay tests using a continuous flow-through bioassay system. A two-ligand site with first-order rate constants model gave a very good description of experimental kinetic data of the change of free Cu2+ concentration. Average k1 was 1.85/h and average k2 was 0.094/h. Bioassay tests indicated that different reaction times of copper with HA solution produced different toxic effects to organisms. We determined the hydrodynamic characteristics of the bioassay chambers to better describe the exposure of the organisms to free Cu2+. The bioassays supported the free ion activity model that the bioavailability and therefore toxicity of copper was directly correlated to the free Cu2+ concentration rather than to the total copper concentration. It was further shown that conventional chemical kinetics can be used to predict the toxicity of copper in these bioassays. This study supports the importance of considering reaction kinetics when studying the chemistry of trace metals in natural waters.
Short-term effects of tri-n-butyl-tin on marine sediment samples using nutrient fluxes as effect indicators
Authors: Dahllöf Ingela , Blanck Hans , Hall Per
Published: March 2010

Tri-n-b utyl-tin (TBT) was shown to affect fluxes of inorganic nutrients from incubated marine sediment samples at extremely low additions of TBTCl, 0.25 femtomol/g (fmol/g) dry sediment (∼80 fg/g). The sediment was incubated under both oxic and anoxic conditions in order to decouple processes in the nitrogen cycle. The fluxes of nitrate and ammonium were affected at an addition of 0.25 fmol TBT/g dry sediment in the oxic incubation. The nitrate flux was stimulated, probably due to stimulation of the autotrophic nitrifiers, causing the negative effect on the ammonium flux. This stimulation is consistent with one suggested mode of action of TBT, i.e., uncoupling of the proton gradient causing free electron flow without ATP production. All fluxes in the anoxic incubations were negatively affected, suggesting a reduced capability for mineralization of organic matter. Nitrate and ammonium fluxes in the anoxic incubations were affected at 2.5 and 8 fmol TBT/g dry sediment, respectively. The fluxes of phosphate and silicate in the anoxic incubation were affected at an addition of 0.25 fmol TBT/g dry sediment. The mode of action of TBT for the heterotrophic microorganisms in the anoxic case is likely to be direct inhibition of ATPase.
Bioaccumulation of 2,4,6-trinitrotoluene and polychlorinated biphenyls through two routes of exposure in a terrestrial amphibian: Is the dermal route significant?
Authors: Johnson Mark S , Franke Laura S , Lee Robyn B , Holladay Steven D
Published: March 2010

Tiger salamanders (Ambystoma tigrinum) were exposed via soil and/or food (earthworms) to 2,4,6-trinitrotoluene (TNT) and a PCB mixture (Aroclor 1260) at environmentally relevant concentrations. Four exposures were considered: (1) uncontaminated food + uncontaminated soil (control group); (2) contaminated soil + uncontaminated food (dermal group); (3) contaminated food + uncontaminated soil (oral group); and, (4) contaminated soil + contaminated food (dual-exposure group). The chemical exposure was estimated for each group by analysis of both soil and earthworms. Body burdens of TNT and its primary metabolites were highest in the dermal groups while PCB burdens were highest in the oral groups. Concentrations of the primary TNT metabolites evaluated, 2-amino-dinitrotoluene (DNT) and 4-amino-DNT, exceeded that of unmetabolized TNT and accumulated to 116 and 670 ng/g, respectively. These results provide evidence that dermal exposures to nitroaromatics in terrestrial salamanders may make an important contribution to total body burden and thus may be important when considering the health consequences of such exposures. Further, the demonstration of the accumulation of TNT and TNT metabolites in a primitive vertebrate may have food web modeling implications.
Higher fluctuating asymmetry as a measure of susceptibility to pesticides in fishes
Authors: Allenbach Dawn M , Sullivan Karen Brown , Lydy Michael J
Published: March 2010

Two species of fishes common to the Great Plains of North America (the western mosquitofish [Gambusia affinis] and the sand shiner [Notropis ludibundus]) were used to examine the relationship between individual time-to-death (TTD) in 96–h toxicity tests and average fluctuating asymmetry (FA). Previous studies have indicated that FA, the random deviation from bilateral symmetry in metric traits, is increased in organisms that develop in stressful and/or marginal environments. This association has led to the prediction that FA may be useful as a bioindicator. For example, if an individual's FA is negatively related to stress resistance, a population that has comparatively high values of FA may be more susceptible to further stressors. Adult fish used in these experiments were captured from natural populations in Kansas and acclimated to laboratory conditions for 1 month before use in toxicity tests. Each species was separately exposed to two insecticides: parathion, an organophosphate, and lindane, an organochlorine. For each TTD test, 200 individuals were exposed over a 96–h period to an LC70 concentration. Dead individuals were removed every 3 h. Individuals that survived the test were sacrificed for comparison to those that died. Measurements for seven external morphologic characters were obtained for each individual and used to estimate average FA. Three of four statistical tests showed a significant negative regression between TTD and average FA, indicating that individuals with smaller FA survived longer in the test conditions. These results support the use of FA as an indicator of susceptibility to pesticides.
Joint action of pollutant combinations (pesticides and metals) on survival (LC50 values) and acetylcholinesterase activity of Tigriopus brevicornis (Copepoda, Harpacticoida)
Authors: Forget Joëlle , Pavillon Jean-François , Beliaeff Benoǐt , Bocquené Gilles
Published: March 2010

The joint toxicity of nine binary mixtures of a metal (arsenic, copper, or cadmium) and a pesticide (carbofuran, dichlorvos, or malathion) was determined in the marine microcrustacean Tigriopus brevicornis (Müller) (Copepoda) by 96-h LC50 tests and measurement of acetylcholinesterase (AChE) inhibition. Acetylcholinesterase is used in the marine coastal environment as a biomarker to evaluate exposure to neurotoxic pollutants, including organophosphorous (OP) and carbamate (C) insecticides and most metals. A toxic unit (TU) approach was used to test the response addition model for mixtures of chemicals with different action modes. Studies of mixtures showed synergistic lethal effects in all cases (the strongest acute effects being observed in coppermalathion, cadmium-malathion, dichlorvos-malathion, and cadmium-dichlorvos combinations). At the sublethal level, the presence of the three metals tested seemed to enhance the inhibitory effects of certain OP and C insecticides.
Concentrations of selenium, mercury, and lead in blood of emperor geese in western Alaska
Authors: Franson J Christian , Schmutz Joel A , Creekmore Lynn H , Fowler Ada C
Published: March 2010

We found up to 10 ppm wet weight of selenium in blood samples collected from emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta in western Alaska, USA. Incubating adult females captured in late May through mid-June 1997 had significantly higher concentrations of selenium in their blood (mean = 5.60 ppm) than adult females captured during wing molt in late July 1996 (mean = 2.78 ppm). Females that nested early or were in good body condition had higher concentrations of selenium in their blood than did other nesting females. Blood samples from 4 of 29 goslings had detectable levels of selenium (mean = 0.14 ppm). Our findings suggest that emperor geese are exposed to more selenium in the marine environment of their wintering and staging areas on the Alaska Peninsula than on the breeding grounds. The highest concentration of mercury found in the blood of emperor geese was 0.24 ppm. One bird had a blood lead concentration of 0.67 ppm, but 82% had no detectable lead in their blood, suggesting that lead exposure from the ingestion of lead shot poses little threat for emperor geese in western Alaska, contrary to findings reported for sympatric spectacled eiders (Somateria fischeri).
Effect of high aluminum consumption on mechanics and composition of furculae of free-ranging coots
Authors: Hui Clifford A , Ellers Olaf
Published: March 2010

High levels of ingested Al can affect mechanical properties of bones. Because of the spring action of the furcula during the wingbeat, small changes in the mechanical properties of this bone may have measurable impacts on long-distance flight. We examined the furculae and ingesta of free-ranging American coots (Fulica americana) in San Francisco Bay (California, USA), where they consume a diet high in Al. We measured the spring stiffness and phase angle (δ) of the furculae and the concentrations of Al, Ca, F, Mg, and P in both the furculae and ingesta. The ingesta had mean Al concentrations (2,384 μg/g, dry weight) and Al:P molar ratios (6.4:1) predicted to affect bone integrity but the bone concentrations of Al were near the normal range and the furcula stiffness did not change with Al concentration. The tan δ of the furculae changed with Al concentration but the relationship was weak. The chemical speciation of the ingested Al may have affected its physiologic role and the high mean levels of ingested calcium (71,283 μg/g, dry weight) very likely neutralized the activity of the Al. Controlled feeding studies have shown that F strengthens avian bones. The bones in our study had molar concentrations of F more than two orders of magnitude greater than Al (170:1) but F appears to have insignificant influence on bone mechanics. The coots in San Francisco Bay apparently are not suffering furcula impairment despite a diet high in Al.
Biochemicall and ultrastructural changes in the liver of baltic salmon SAC FRY suffering from high mortality (M74)
Authors: Pesonen Maija , Andersson Tommy B , Sorri Virpi , Korkalainen Merja
Published: March 2010

A high percentage of feral Baltic salmon suffers from an abnormal type of sac fry mortality, designated as the M74 syndrome. Although the cause of the mortality is not known, it has been proposed that a high burden of lipophilic xenobiotics is a contributing factor. The objective of the present study was to investigate hepatocyte ultrastructure and liver biochemical anomalies that could be related to exposure to lipophilic xenobiotics in feral Baltic salmon sac fry. Electron microscopy of M74 sac fry liver revealed a dilatation of endoplasmic reticulum, numerous myelin figures, some swelling mitochondria, and an accumulation of lipid droplets. The ratio of reduced glutathione to oxidized glutathione content in M74 sac fry liver was about 60% of that found in the control sac fry liver. Glutathione reductase, an enzyme responsible for reducing oxidized glutathione to reduced glutathione (GSH), was elevated in the M74 sac fry liver, indicating an adaptive response to an increased demand for GSH. Hepatic glutathione S-transferase activity was significantly higher in the M74-affected sac fry liver compared with that of the normally developing sac fry liver, whereas glutathione peroxidase activity was at about the same level in the two groups. Hepatic cytochrome P4501A (CYP1A) activity and protein content and NADPH cytochrome c reductase activity were higher in the liver of M74 sac fry than in the liver of normally developing sac fry. Anti-trout LMC2 (CYP2K1) recognized two protein bands, one of which was elevated in the M74 sac fry liver. In conclusion, the damage and biochemical changes recorded here, in combination with poor vitamin status in the M74 sac fry, may contribute substantially to the mortality.
Chronic effects of atrazine on tolerance of a benthic diatom
Authors: Nelson Karen J , Hoagland Kyle D , Siegfried Blair D
Published: March 2010

The effects of prior chronic exposure to atrazine on responses to subsequent acute exposures were investigated using a common benthic diatom. Clonal, axenic cultures of Craticula cuspidata were established from the Platte River (Nebraska) and obtained from a culture collection (unlikely prior exposure to atrazine). All cultures received a chronic 67-d treatment of 1 μg/L atrazine, and growth was monitored using fluorometric detection of chlorophyll a. Chronic atrazine exposure significantly reduced growth rate only during the first day of treatment (p = 0.0001); no significant effect was detected throughout the remainder of the 67-d period. Following the chronic treatment, clones were exposed to six atrazine concentrations (83, 188, 402, 860, 1,782, and 3,250 μg/L) to ascertain whether prior exposure influenced the tolerance of this diatom. Prior chronic exposure had a negative effect on growth following subsequent exposures to higher concentrations. A significant decline in growth was detected on days 7, 9, and 12 between previously exposed and control clones at 83 μg/L of atrazine. The lack of increased tolerance in C. cuspidata after a realistic chronic exposure indicates that the levels of atrazine presently found in many lotic systems may inhibit the growth of periphyton during periods of higher pulses of atrazine characteristic of spring runoff events.
Effects of 3,3′,4,4′,5,5′-hexachlorobiphenyl on cytochrome P4501A and estrogen-induced vitellogenesis in rainbow trout (Oncorhynchus mykiss)
Authors: Donohoe Regina M , Wang-Buhler Jun-Lan , Buhler Donald R , Curtis Lawrence R
Published: March 2010

Estrogen-regulated synthesis of vitellogenin (Vg), a yolk-protein equired for reproduction, was monitored to explore the potential antiestrogenic effects of the coplanar polychlorinated biphenyl (PCB), 3,3′,4,4′,5,5′-hexachlorobiphenyl (3,4,5-HCB), in juvenile rainbow trout (Oncorhynchus mykiss). The effects of 17β-estradiol on 3,4,5-HCB induction of cytochrome P4501A (CYP1A) were also examined. Trout were injected with 3,4,5-HCB (0.25, 2.5, 25, 50, or 100 mg/kg) or a vehicle control, and after 10 weeks, they were sampled or injected with 17β-estradiol (0.1 mg/kg). Markers of vitellogenesis, such as liver somatic index, hepatic estrogen-binding sites, and plasma Vg concentrations, in 17β-estradiol-treated fish were not affected by 3,4,5-HCB. Maximal induction of CYP1A protein and mRNA occurred at doses above 2.5 mg/kg, and 17β-estradiol reduced CYP1A protein content at a single dose (0.25 μg 3,4,5-HCB/kg). Ethoxyresorufin-O-deethylase (EROD) activity was induced by 3,4,5-HCB doses of between 0.25 and 2.5 mg/kg, but induction was reduced at higher doses, indicating that 3,4,5-HCB suppressed CYP1A catalytic activity. In 3,4,5-HCB/17β-estradiol—treated fish, plasma estradiol was significantly reduced at 100 mg 3,4,5-HCB/kg, but the depression was not associated with CYP1A induction or with other antiestrogenic effects. Although CYP1A was induced, 3,4,5- HCB did not interfere with vitellogenesis, which suggests that the PCB congener is not a potent antiestrogen in rainbow trout.
Remediating hexahydro-1,3,5-trinitro-1,2,5-trazine-contaminated water and soil by fenton oxidation
Authors: Bier Eleanor L , Singh Jasbir , Li Zhengming , Comfort Steve D , Shea Patrick J
Published: March 2010

Soils surrounding the former Nebraska Ordnance Plant (NOP) and other military installations are highly contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Because RDX is mobile in soil and recalcitrant at high concentrations, soil remediation is needed to reduce environmental hazards. Conventional treatment by incineration is costly and often creates strong public opposition. We propose an alternative treatment using the Fenton reagent (Fe2 + H2O2) to remediate RDX-contaminated water and soil. Treating an aqueous solution of RDX with the Fenton reagent resulted in complete RDX destruction within 24 h. Ultraviolet irradiation in combination with Fenton reagent enhanced both RDX transformation and mineralization. Mass balance experiments with 14C-RDX indicated that, within 12 h of Fenton oxidation, 76% of the initial 14C activity was lost from solution, the majority of which (68%) was recovered as 14CO2. Additional products resulting from Fenton oxidation of RDX included NH+4, NO−3, and formic acid; we also present evidence that methylene dinitramine is formed. The U.S. EPA remediation goal (5.8 mg RDX/kg) for the NOP site was achieved when the Fenton reagent was added incrementally to RDX-contaminated soil slurries at elevated temperature (45°C). These results support the use of the Fenton reaction for remediating RDX-contaminated water and soil.
Aqueous solubility, octanol solubility, and octanol/water partition coefficient of nine hydrophobic dyes
Authors: Sijm Dick T H M , Schüürmann Gerrit , de Vries Pieter J , Opperhuizen Antoon
Published: March 2010

The aqueous solubilities (Sw), the octanol/water partition coefficients (Kow), and the solubilities in octanol (Soct) of a series of nine hydrophobic anthraquinone and azo dyes have been experimentally determined. Some dyes show more than one aqueous solubility, which is probably due to their polymorphic crystalline forms. Sw ranged from 1 μg/L to 1 mg/L, the log Kow ranged from 3.6 to > 5.8, and Soct ranged from 10 to 3,000 mg/L. The dyes are not only hydrophobic but lipophobic as well. The most important finding is that there is a discrepancy between the Kow and the ratio Soct/Sw for the dyes, while there is a relatively good relationship between either Sw or Soct and the ratio Soct/Sw. The discrepancy probably explains why estimated values of Sw and Kow generally underestimated the experimental ones and that none of the calculated molecular properties (molecular weight, surface area, and volume) was highly correlated to either Sw or Kow. The results show that insufficient knowledge is available to understand and predict the magnitude of the physicochemical properties of the dyes. Therefore, these properties should be preferably experimentally determined.
Fate of a metal-resistant inoculum in contaminated and pristine soils assessed by denaturing gradient gel electrophoresis
Authors: Stephen John R , Chang Yun-Juan , Macnaughton Sarah J , Whitaker S Leigh , Hicks Christopher L , Leung Kam T , Flemming Cecily A , White David C.
Published: March 2010

Cesium, cadmium, cobalt, and strontium are four contaminants frequently found in soils at biotoxic levels. Introduction of certain nongenetically modified bacteria has been frequently suggested as a method for the immobilization of heavy metal contaminants in soil, thereby reducing runoff and bioavailability. In this study, we have used the polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) to track the survival of five bacterial species added to soil microcosms with and without the addition of a mixture of these metals. The PCR primers targeted conserved regions of the 16S rDNA molecule present in all bacteria. The reaction products were shown to reflect the relative abundance of the bacteria both in mixtures of pure cultures and against a background of all the eubacterial species present in the soil following inoculation. Three of the species (Pseudomonas aeruginosa FRD-1, Shewanella putrifaciens 200, and Desulfovibrio vulgaris Hildenborough) decreased rapidly following inoculation into both soils. The proportion of Alcaligenes eutrophus CH34 remained at a constant level throughout the 8-week experiment in both soil treatments. Sphingomonas aromaticivorans B0695 showed toxic metal-dependent survival in that its relative abundance dropped rapidly in pristine soil but remained at approximately inoculation levels throughout the experiment in contaminated microcosms.
Genotoxicity of two polycyclic aromatic hydrocarbons declines as they age in soil
Authors: Alexander Renee R , Alexander Martin
Published: March 2010

Rifampicin-resistant mutations were induced in Pseudomonas putida A11rUV growing in soil containing 9,10-dimethyl-1,2-benzanthracene and benzo[a]pyrene. Aging of the compounds for 7 d caused a marked decrease in the mutation rates, and the number of mutants was further reduced after 15 d of aging. Longer persistence of the compound in soil did not further diminish the number of mutants. Vigorous solvent extraction showed that the concentration of the compounds had not diminished with the marked decline in genotoxicity. The data demonstrate that genotoxicity of such compounds aged in soil declines with little or no loss of the compound.
Three-phase modeling of polycyclic aromatic hydrocarbon association with pore-water-dissolved organic carbon
Authors: Mitra Siddhartha , Dickhut Rebecca M
Published: March 2010

Log–log plots of measured organic carbon-normalized sediment pore-water distribution coefficients (K′OCS) for several polycyclic aromatic hydrocarbons (PAHs) versus their octanol-water partition coefficients (K′owS) at two sites in the Elizabeth River, Virginia, show large deviations from linearity. Organic-carbon normalized distribution coefficients for these PAHs between sediments and pore waters decreased by more than two orders of magnitude with depth as well. To determine to what extent pore water dissolved and colloidal organic carbon (DOC) was responsible for the observed nonlinearity and decrease in K′OC, a three-phase model was used to estimate pore-water PAH-DOC binding coefficients (KDOC). Partitioning of PAHs to pore-water DOC (i.e., KDOC) enhances the observed “dissolved” phase PAH concentration, especially for high-Kow compounds, contributing to the nonlinearity in K′OC-Kow plots. However, our application of the three-phase partitioning model to these data indicate that, at most, pore-water PAH-DOC binding accounts for one order of magnitude of the observed decrease in K′OC with depth in the sediment bed. The results of this study are consistent with three-phase partitioning theory for hydrophobic organic compounds between sediment organic matter, pore-water DOC, and freely dissolved aqueous phases in natural systems.
Organochlorine pesticides and polychlorinated biphenyls in household composts and earthworms (Eisenia foetida)
Authors: Wågman Nadja , Strandberg Bo , van Bavel Bert , Bergqvist Per-Anders , Öberg Lars , Rappe Christoffer
Published: March 2010

Three indoor, household composts and the earthworms living in them were analyzed for their congener-specific content of polychlorinated biphenyls (PCBs) and organochlorine pesticides, including DDTs, chlordanes, dieldrin, and penta- and hexachlorobenzene. The concentrations of the chlordanes were 0.01 to 0.2 ng/g dry weight (dw) in compost and 0.03 to 0.06 ng/g wet weight (ww) in the worms. Of all the pesticides, the DDTs and chlorobenzenes were found in the highest concentrations. The levels of PCBs found in the composts were 32 to 440 ng sum PCB/g dw and 23 to 290 ng/g ww in the worms. These observations are in strong agreement with reported data from studies of outdoor composts. The PCB congener pattern was similar to that of commercial technical mixtures (dominated by tetrachlorinated PCBs) in contrast with data reported from outdoor composts.
Long-term bioconcentration kinetics of hydrophobic chemicals inSelenastrum capricornutumandMicrocystis aeruginosa
Authors: Koelmans Albert A , van der Woude Hannelore , Hattink Jasper , Niesten Dominique J M
Published: March 2010

The bioconcentration of two chlorobenzenes (CBs) and of seven polychlorobiphenyls (PCBs) to Selenastrum capricornutum and Microcystis aeruginosa was studied with accumulation experiments followed by gas purge elimination experiments. Henry's law constants at 10°C were needed to interpret the gas purge results and were measured in control experiments. For the M. aeruginosa culture, steady-state uptake was reached within days, whereas uptake by S. capricornutum took several weeks. The relationships between the log bioconcentration factors (BCF) and log octanol–water partition coefficients (Kow) were nonlinear, with relatively low values for the more hydrophobic PCBs. Rate constants for the elimination of CBs and PCBs from the algal cells were shown to be larger than 1 per day when calculated with a one-compartment model. With such large rate constants, it is unlikely that the curvature observed for these species is caused by slow kinetics or that algal growth affects BCF by dilution of CB or PCB concentrations. The log BCF–log Kow relationships could be described by a simple three-phase model that accounted for the binding of CBs and PCBs to dissolved organic carbon (DOC). Modeling bioconcentration of hydrophobic chemicals in phytoplankton should account for the binding to DOC.
Toxicity of copper-spiked sediments to Tubifex tubifex (oligochaeta, tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay
Authors: Vecchi Martina , Reynoldson Trefor B , Pasteris Andrea , Bonomi Giuliano
Published: March 2010

Two sediment bioassay methods using Tubifex tubifex (Müller, 1774) as the test species were compared. The first was an adult reproduction test, the second an early-life-stage survival test. The duration of both bioassays is 28 d and the amount of work required was similar; they may be useful alternatives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bioassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used; five separate, nonsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a food supplement. In the adult bioassay, there were large differences in the production of cocoons, eggs, and young among the control treatments of the five experiments. There were also major differences in the NOEC (no-observed-effect concentration) and LOEC (lowest-observed-effect concentration) for copper between the tested substrates. The early life stage bioassay appears to be less sensitive to copper toxicity than the adult reproductive bioassay since NOECs and LOECs are higher for early survival than for the most sensitive endpoints of the adult bioassay in three experiments out of five.
Copper binding affinity of rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) gills: Implications for assessing bioavailable metal
Authors: MacRae Russell K , Smith Darren E , Swoboda-Colberg Norbert , Meyer Joeseph S , Bergman Harold L
Published: March 2010

In this study, we determined the conditional stability constant (log K′) of copper for the gills of rainbow trout (Oncorhynchus mykiss; RBT) and brook trout (Salvelinus fontinalis; BT). Using toxicity-based complexation bioassays, which measure the effect of competing organic ligands on copper toxicity, the RBT gill copper log K′ range was 6.4 to 7.2. Using a Scatchard analysis of gill Cu accumulation, the RBT log K′ was 7.50 and the BT log K′ was 7.25. The close agreement in RBT log K′ values between these two methods suggests that measurement of gill copper accumulation is an acceptable alternative for determining a toxicity-based gill copper binding affinity. Our results also suggest that there is either a single gill copper binding component or, more realistically, multiple components with similar binding properties that function collectively to define a single toxicologically relevant copper conditional stability constant. These results suggest analytical approaches to measuring bioavailable metal concentrations, such as geochemical modeling where biological ligands are included in speciation calculations, may adequately simulate complex biological ligands. A method to convert gill copper accumulation to a bioavailable water criterion is also discussed.
Lead exposure in passerines inhabiting lead-contaminated floodplains in the Coeur D'Alene River Basin, Idaho, USA
Authors: Johnson Gregory D , Audet Daniel J , Kern John W , LeCaptain Leonard J , Strickland M Dale , Hoffman David J , McDonald Lyman L
Published: March 2010

Blood collected from song sparrows (Melospiza melodia) and American robins (Turdus migratorius) captured with mist nets in a lead-contaminated (assessment) area and nearby uncontaminated (reference) areas within the Coeur d'Alene Basin in northern Idaho was analyzed for δ-aminolevulinic acid dehydratase activity (ALAD) and hematocrit levels, and livers were analyzed for lead. Mean ALAD inhibition in the assessment area was 51% in song sparrows and 75% in American robins. The proportion of the sampled population with ALAD inhibition >50% was calculated to be 43% for song sparrows and 83% for American robins. Assessment area hematocrit values for song sparrows (x = 39.9) and American robins (x = 39.5) were lower than in reference areas (x = 42.4 for song sparrows and 40.2 for American robins); however, differences were not statistically significant (p > 0.05). Significantly higher levels of lead (wet weight) were found in livers from song sparrows captured on the assessment area (x = 1.93 ppm) than on reference areas (x = 0.10 ppm) (p = 0.0079). Study results indicate that 43% (95% confidence interval [CI] = 12.9-77.5%) of the song sparrows and 83% (95% CI = 41.8-99.2%) of the American robins inhabiting the floodplain along the Coeur d'Alene River in the assessment area are being exposed to lead at levels sufficient to inhibit ALAD by > 50%. Variability in lead exposure indicators was attributed to high variability in environmental lead concentrations in the Coeur d'Alene River Basin.