bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the computer-automated structure evaluation (CASE) program to the study of structure-biodegradation relationships of miscellaneous chemicals
Authors: Klopman Gilles , Balthasar D. M. , Rosenkranz H. S.
Published: March 2010

The computer-automated structure evaluation (CASE) methodology has been used to investigate the correlation between chemical structure and rate of biodegradation. A training set consisting of 283 diverse organic chemicals of known biodegradation activity was evaluated. Computer-automated structure evaluation identified six major activating fragments that contained oxygen in a carbonyl or hydroxyl group, suggesting that the presence of oxygen plays a significant role in biodegradation. The training set predicts the biodegradation categories correctly 74% of the time for an independent validation set of 27 chemicals. By also using a data base of diverse chemicals whose activity was based on acclimated inocula, two prediction results were obtained for each of the 27 chemicals of an independent validation set. Analysis of the results showed that the chemicals could be grouped into five prediction categories. Two of these categories included chemicals for which both data bases predicted exactly the same activity, whereas a third category contained two chemicals for which no conclusion was made. The other two categories include chemicals of intermediate activity, that is, chemicals that can undergo slow or fast biodegradation, depending on the conditions. In addition, the identification of activating structural fragments has provided information on mechanisms for biodegradation in the environment.
Lead and cadmium accumulation in eggs and fledgling seabirds in the New York bight
Authors: Burger Joanna , Gochfeld Michael
Published: March 2010

We measured lead and cadmium concentrations in eggs and in the breast feathers of fledglings of common tern (Sterna hirundo), roseate tern (S. dougallii), Forster's tern (S. forsteri), black skimmer (Rynchops niger), and herring gull (Larus argentatus) nesting in mixed-species colonies in the New York Bight in 1989. Metal concentrations in fledgling feathers represent in part metals sequestered in the egg by females and accumulation from food brought back to chicks by parents, and thus may be a measure of local metal acquisition. There were significant interspecific differences in lead in eggs, and lead and cadmium in fledgling feathers. Herring gulls had the most lead in eggs (up to means of 6,740 ng/g, dry weight), whereas the terns had the least (mean of 318 ng/g, dry weight). Cadmium concentrations were generally low in all examined eggs (<22 ng/g, dry weight). Lead concentrations were high in fledgling feathers (up to 4,090 ng/g, dry weight) in some populations of all species. Cadmium was highest in fledgling feathers of herring gull and skimmers. Among fledgling terns, the roseate tern (a federally endangered species) had the highest concentrations. For all species except herring gull, the feathers of fledglings had higher levels of metals than did eggs.
Aqatic toxicity equivalency factors for chlorinated phenolic compounds present in pulp mill effluents
Authors: Kovacs T. G. , Martel P. H. , Voss R. H. , Wrist P. E. , Willes R. F.
Published: March 2010

Aquatic toxicity equivalency factors (TEFs) for chlorinated phenolic compounds present in blached kraft mill effluents were estimated using published chronic toxicity data for fathead minnows, rainbow trout, zebra fish, American flagfish, and sea urchins. To provide the most consistent and reliable approach for estimating relative toxicity, each set of toxicity data employed for TEF determination encompassed only data relating to a common toxic end point, a single aquatic test species, and a common method of testing and of statistical analysis. The TEF values were determined as a ratio of the chronic threshold values for the mono-to pentachloro-substituted phenolics to that for pentachlorophenol, where the threshold values were obtained from linear regression equations relating chronic toxicity to the number of chlorine substituents for a given chlorinated phenolic. Using this approach, the TEF values for monochloro-, dichloro-, trichloro-, tetrachloro-, and pentachloro-substituted phenolic compounds were determined to be 0.04, 0.1, 0.2, 0.5, and 1.0, respectively.
Identification of methyl parathion toxicity in colusa basin drain water
Authors: Finlayson B. J. , Harrington J. A. , Fujimura R. , Isaac G.
Published: March 2010

The cause of toxicity to young striped bass Morone saxatilis and mysids Neomysis mercedis from an agricultural drain (Colusa Basin Drain, Sacramento River Valley, CA) containing tail water from rice fields was investigated. Previous studies had postulated that toxicity was due to one or more of the insecticides carbofuran, malathion, and methyl parathion used on rice in California. The discharge of insecticide-tainted agricultural drain water into the Sacramento River may have contributed to the decline of the striped bass population in the Sacramento-San Joaquin Estuary, either directly by mortality or indirectly by reducing food items such as mysids. Trace metals cadmium, copper, and zinc from abandoned mining operations may also have contributed toxicity. Water samples were collected from the Colusa Basin Drain and upstream and downstream from the Sacramento River, analyzed for insecticides and trace metals, and tested for toxicity. No significant toxicity to striped bass was observed for either water body, and no significant toxicity to Neomysis mercedis was observed for the Sacramento River sites. However, Colusa Basin Drain water was significantly toxic to Neomysis mercedis, which was attributed to lethal (up to three times the 96-h LC50 value) concentrations of methyl parathion. The trace metals, carbofuran, and malathion were present at less than acutely toxic concentrations. The addition of 2 ppt salinity appeared to increase survival of both test organisms. This study clearly demonstrates the need for reducing environmental levels of methyl parathion.
Measurement of tributyltin contamination of sediments and Crassostrea virginica in the southern chesapeake bay
Authors: Espourteille Francois A. , Greaves John , Huggett Robert J.
Published: March 2010

Tributyltin concentrations in sediments and American oysters, Crassostrea virginica, from the southern Chesapeake Bay have been determined. Concentrations in both sediments and oysters were correlated with commercial shipping and recreational boating activity. Sediment concentrations as high as 4,000 μg kg−1 dry weight were observed in a marina. Detection limits in sediment were 1 to 14 μg kg−1, depending on sediment type. Tributyltin was found in all Crassostrea virginica, including [those from] locations where the compound could not be detected in sediment. Concentrations in Crassostrea virginica ranged from < 10 μg kg−1 dry weight on the Atlantic Coast of Virginia to 5,600 μg kg−1 in the Elizabeth River, Virginia.
Predicting the acute toxicity of copper in freshwater sediments: Evaluation of the role of acid-volatile sulfide
Authors: Ankley Gerald T. , Mattson Vincent R. , Leonard Edward N. , West Corlis W. , Bennett Jon L.
Published: March 2010

Acid-volatile sulfide (AVS) has been proposed as an important partitioning phase determining the bioavailability of cationic metals in sediments. The objective of this research was to evaluate the role of AVS in determining copper toxicity in sediments from two sites heavily contaminated with copper: Steilacoom Lake, Washington, and the Keweenaw Watershed, Michigan. Sediments from the two sites were used in 10-d toxicity tests with the amphipod Hyalella azteca, and results of the toxicity tests were compared to bioavailability predictions based on copper and AVS concentrations in the test sediments, as well as copper concentrations in the sediment interstitial (pore) water. Normalization of sediment copper concentrations to AVS accurately predicted sediments that were nontoxic when molar copper-to-AVS ratios were less than one; however, toxicity also was frequently not observed in samples with molar copper-to-AVS ratios significantly greater than one. In contrast, measurement of pore-water copper concentrations and subsequent comparison of these concentrations to water-only copper toxicity data for Hyalella azteca resulted in accurate predictions of the presence and extent of copper toxicity in the test sediments. These results indicate that AVS alone is not an appropriate partitioning phase for predicting copper bioavailability in freshwater sediments.
Effects of chemical contaminants on blood chemistry of teleost fish: A bibliography and synopsis of selected effects
Authors: Folmar Leroy C.
Published: March 2010

The purpose of this article is to provide a bibliography of publications that describe the effects of organic and inorganic chemical contaminants on serum chemistry and hematology of teleost fish with a brief synopsis of those effects. Also included is a review of “normal” or “reference” values for various blood chemistry parameters and hormones measurable in a number of fish species.
Use of gleams to predict insecticide losses from pine seed orchards
Authors: Nutter W.L. , Knisel W.G. , Bush P.B. , Taylor J.W.
Published: March 2010

Intensive pine forest management practiced in the southern United States relies heavily on seed orchards to produce genetically improved seedlings to achieve high productivity. One of the most critical problems is the control of seed and cone insects requiring heavy and frequent applications of insecticides. Hydrologic modeling of insecticide fate in surface water and ground water is a useful technique for evaluating the environmental fate of the applied insecticides. The GLEAMS (groundwater loading effects of agricultural management systems) model was used to evaluate the differences between fate of insecticides at four pine seed orchard sites in different physiographic regions of the southern United States. A 50-year simulation period was used. Insecticides selected for simulation were carbofuran, azinphosmethyl, fenvalerate, and permethrin. The simulations of insecticide losses in storm flow and percolate at each of the seed orchards demonstrated the importance of the time of application relative to precipitation occurrence, effective rooting depth, and soil-water conditions. Although the absolute insecticide losses may not be accurately simulated by GLEAMS, the model can predict the seasonal patterns of loss and relative loss among different insecticides likely to occur under actual seed orchard conditions.
Lethal and sublethal impacts of pyrethroid insecticides on amphibian embryos and tadpoles
Authors: Berrill Michael , Bertram Susan , Wilson Anne , Louis Sharon , Brigham Deneen , Stromberg Christina
Published: March 2010

Amphibian populations are potentially sensitive to aquatic contaminants such as pesticides. We exposed embryos and larvae of five amphibians (the frogs Rana sylvatica, Rana pipiens, Rana clamitans; the toad Bufo americanus; the salamander Ambystoma maculatum) to one or both of the pyrethroid pesticides permethrin and fenvalerate. Concentrations ranged from 0.01 ppm to 2 ppm, and exposures lasted 22 or 96 h. No significant mortality of embryos, anuran tadpoles, or salamander larvae occurred during or following exposure to pyrethroids. However, tadpole growth was delayed following exposure, and tadpoles and salamander larvae responded to prodding not by darting away but by twisting abnormally. Both effects may result in greater vulnerability to predation. Recovery of normal avoidance behavior occurred more rapidly at 20 than at 15°C and following exposure to lower concentrations of the pesticides, indicating both temperature and dose effects. Tadpoles exposed later in development did not feed for a period of days following exposure but were still capable of metamorphosis. Of the five tested species, Ambystoma maculatum, a tadpole predator, was particularly sensitive. An amphibian community is therefore likely to be sensitive to low-level contamination events.
Application of passive samplers (pisces) to locating a source of PCBs on the Black River, New York
Authors: Litten Simon , Mead Berton , Hassett John
Published: March 2010

Dissolved hydrophobic chemicals can be concentrated with a passive, in situ concentration-extraction sampler (PISCES), an inexpensive and easy-to-use device made from plumbing parts and polyethylene film. PISCES is intended to mimic the direct uptake of chemicals from water by fish without the complications of metabolism and the uncertainty of location of exposure. This report examines the practical application of PISCES to a problem in identifying the source of PCBs to the Black River (NY). PISCES were deployed on three occasions at stations throughout the length of the river. Solvent recovered from the PISCES was analyzed for polychlorinated biphenyl (PCB) congeners. Relative homolog abundances and absolute amount of recovered PCBs pointed to a particular river reach as a possible source. A fourth set of samples taken in the city of Carthage (NY) defined a plausible source. Conventional sampling methods would not have been effective in this situation.
Derivation of site-specific ammonia criteria for an effluent-dominated headwater stream
Authors: Diamond Jerome M. , MacKler Donald G. , Rasnake William J. , Gruber David
Published: March 2010

The present study was designed to derive appropriate ammonia standards for a freshwater, wooded stream on the Delmarva Peninsula (eastern shore of the United States) composed almost entirely of wastewater effluent for at least four months of the year. Representative species acute and chronic toxicity tests were performed at 20° (summer) and 12°C (winter) to obtain seasonal standards. Acute toxicity tests using fathead minnow and Daphnia magna suggested that the site water had no effect on un-ionized ammonia toxicity. However, resident species appeared to be relatively insensitive to acute exposures of un-ionized ammonia. Warm-water LC50s adjusted for pH = 8.0 and 20°C ranged between 1.02 and 2.73 mg/L for those tests in which an LC50 could be calculated. If acute no-observed-effect concentrations (NOECs) (approximately LC25) were used, bluegill was most sensitive (NOEC = 0.295 mg/L), followed by Crangonyx (amphipod) and Menidia (silverside). Warm-water chronic testing indicated that Rana (leopard frog) was most sensitive, followed by bluegill and amphipod. Cold-water acute tests yielded definitive LC50s between 0.53 (bluegill) and 1.91 mg/L (amphipod). Hyla crucifer (spring peeper) and juvenile bluegill were most sensitive in chronic cold-water testing. Final acute values (FAVs) of 0.62 and 0.30 mg/L NH3 were obtained for 20 and 12°C, respectively. The geometric mean of acute-to-chronic ratios (ACR) based on unionized ammonia were 7.2 and 5.7, for 20 and 12°C, respectively. The final chronic values (FCVs) or maximum 4-d average concentrations at 20 and 12°C were 0.09 and 0.05 mg/L NH3, respectively. Un-ionized ammonia acute toxicity to vertebrate freshwater species (fish and tadpoles) was inversely related to temperature, whereas invertebrates often exhibited the opposite trend. Chronic testing, however, suggested that most species were more sensitive to NH3 at 20 than 12°C. This study suggests that the ACR developed by the U.S. Environmental Protection Agency (EPA) for warm-water streams may be overly conservative for very small streams in which species diversity is naturally low.
Multivariate quantitative structure-activity relationships for polychlorinated dibenzo-p-dioxins and dibenzofurans
Authors: Tysklind Mats , Lundgren Kjell , Rappe Christoffer , Eriksson Lennart , Jonsson Jörgen , Sjöström Michael
Published: March 2010

A multivariate characterization of the 136 tetra- to octa-chloro-substituted dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) is reported. By principal component analysis (PCA) of a battery of physicochemical descriptors, an overview of similarities and differences between congener groups and substitution patterns is obtained. Available data for two biochemical end points, the induction of the enzymes aryl hydrocarbon hydroxylase (AHH) and ethoxy resorufin O-deethylase (EROD), were used to construct quantitative structure-activity relationships (QSARs) using partial least-squares projections with latent variables (PLS). By applying the principles of statistical experimental design to the orthogonal scores from the PCA, a set of PCDD and PCDF congeners is proposed for further biological and toxicological evaluations.
Selective accumulation of polychlorocamphenes in aquatic biota from the canadian Arctic
Authors: Bidleman T. F. , Walla M. D. , Muir D. C. G. , Stern G. A.
Published: March 2010

Polychlorocamphenes (PCCs; e.g., toxaphene) are major organochlorine contaminants in fish, marine mammals, and other aquatic life from the Arctic. Because PCCs yield complex GC patterns that are often greatly altered in environmental samples compared to a toxaphene standard, identification by GC with electron-capture detection is problematic. We examined PCC profiles in the blubber of narwhal (Monodon monoceros) and the liver of freshwater burbot (Lota lota) from the Canadian Arctic by GC-negative ion mass spectrometry (GC-NIMS). Chromatograms of these specimens showed that certain PCCs were greatly enriched, compared to a toxaphene standard. Mass spectra of accumulated PCCs were consistent with octachloro- and nonachlorobornanes, with possible contribution from chlorinated bornenes. Corresponding GC peaks in the toxaphene standard appeared to be mixtures of seven- and eight-chlorine or eight- and nine-chlorine PCCs. The same peaks in biological samples showed selective accumulation of the more highly chlorinated components. To properly characterize the levels and biological effects of PCCs in arctic food chains will require isolation or synthesis of pure PCC congeners and an evaluation of their physicochemical and toxicological properties.
The effects of low pH and elevated aluminum on yellowstone cutthroat trout (Oncorhynchus clarki bouvieri)
Authors: Farag Aïda M. , Woodward Daniel F. , Little Edward E. , Steadman Bryan , Vertucci Frank A.
Published: March 2010

Although acid deposition is not considered a problem in the western United States, surface waters in high elevations and fish inhabiting these waters may be vulnerable to acidification. This study examined the sensitivity of a western salmonid to acid and aluminum stress. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri; YSC) were exposed for 7 d during each of four early life stages, or continuously from fertilization to 40 d post-hatch, to decreased pH and elevated Al. We monitored survival, growth, whole-body ion content, and behavior of the exposed fish. Sensitivity of early life stages of YSC may be expressed by survival or by survival and sublethal effects. In our study, eggs were the most sensitive life stage of YSC to low pH if survival alone was considered. However, the sublethal effects on growth, tissue ion content, and behavior revealed the alevins and swim-up larvae were more sensitive to reduced pH and increased Al than eggs or eyed embryos. We also observed that survival was significantly decreased if YSC were exposed to pH 6.0 and 50 μg Al per liter continuously from fertilization to 40 d post-hatch.
Effects of previous zinc exposure on pH tolerance of periphyton communities
Authors: Niederlehner B. R. , Cairns John
Published: March 2010

The community-level effects of previous chemical exposure on resistance to a dissimilar subsequent stress were evaluated. Naturally derived periphytic communities on polyurethane-foam artificial substrates provided colonists for development of new communities under controlled stress conditions in the laboratory. Communities were colonized under three levels of Zn stress: control, low (73 μg/L), and high (172 μg/L). After 21 d, laboratory-colonized communities were exposed to 5 pH levels (control, 4.5, 4.0, 3.5, 3.0) for 48 h. No significant differences occurred between Zn treatments in response to pH for total biomass, assimilation ratio, respiration to biomass ratio, and net daily metabolism. Response to pH was dependent on Zn treatment for number of protozoan species, algal biomass, gross primary productivity, and community respiration. Number of protozoan species in high Zn was impaired in absence of pH stress. Primary production and community respiration were impaired in absence of pH stress in both low and high Zn. For these three end points, outcome for Zn treatments converged with increasing secondary stress; no differences between Zn treatment groups were observed at pH < 4.0. For several end points, Zn-stressed communities changed less, relative to their initial state, with subsequent acid shock.
Comparative toxicity of selenate, selenite, seleno-DL-methionine and seleno-DL-cystine to Daphnia magna
Authors: Maier Kurt J. , Foe Christopher G. , Knight Allen W.
Published: March 2010

Elevated concentrations of the trace element selenium (Se) have resulted in the degradation of several aquatic ecosystems. This study evaluated the comparative toxicity of several aqueous chemical species of selenium to an aquatic cladoceran, Daphnia magna. Responses to mixtures of these selenium forms, varying the sulfate concentration, were also examined. Initial experiments compared the toxicity of aqueous forms of selenate, selenite, seleno-DL-methionine, and seleno-DL-cystine to neonate Daphnia magna, resulting in 48-h LC50 values of 2.84, 0.55, 0.31, and 2.01 mg Se per liter, respectively. Immobilization was an acute sublethal response observed during exposure to the organic selenium forms only. The 48-h IC50 values were 0.045 and 0.52 mg Se per liter for seleno-DL-methionine and seleno-DL-cystine, respectively. Evaluation of the invertebrate response to various combinations of selenate, selenite, and seleno-DL-methionine demonstrated that the toxicities of these forms of selenium are additive. Increasing the concentration of sulfate decreased, varied, and left unaffected the toxicities of selenate, selenite, and seleno-DL-methionine, respectively. These results indicate that both the chemical form of selenium and the sulfate concentration can influence the toxicity of selenium.
Bile fluorescence and some early biological effects in fish as indicators of pollution by xenobiotics
Authors: Britvić Smiljana , Lucić Davor , Kurelec Branko
Published: March 2010

Simple measurement of bile fluorescence in fish has been proposed as a means for determining exposure to certain waterborne chemicals. This proposal was based on the data obtained by chemical determination of metabolites of compounds to which fish were exposed. Because exposures to most of these compounds cause some profound biological effects in fish, we studied the correlation between the increase in bile fluorescence, the induction of liver benzo[a]pyrene mono-oxygenase (BaPMO) activity, and the increase in the potential of liver to bioactivate promutagenic benzo[a]pyrene to Salmonella typhimurium TA100 mutagens. Carp exposed to diesel-2 oil, crude oil, or to a flow of polluted river water simultaneously increased severalfold the levels of all three parameters in a dose-and time-dependent manner. During the recovery from exposure, the levels of bile fluorescence and the BaPMO activity declined and by day 15 reached their natural, preexposure levels. The level of bioactivation potential, however, remained at the higher, induced level throughout the recovery period of 15 d. Seven fish species living in polluted Sava River (near Zagreb, Croatia) revealed severalfold increased levels of these parameters, as compared to their levels in fish living in the reference Korana River (near Karlovac, Croatia) or to their levels in control carp. These results give qualitatively new support to the idea of using simple measurements of fluorescence of diluted bile as a rapid and cheap complementary investigative tool for monitoring and assessment studies.
Selenium accumulation and loss in mallard eggs
Authors: Heinz Gary H.
Published: March 2010

Five female mallards (Anas platyrhynchos) that had just started egg laying were first fed a diet containing 15 ppm selenium in the form of selenomethionine for 20 d and then an untreated diet for 20 d. Selenium levels in eggs peaked (to about 13-20 ppm) in about two weeks on the treated diet and leveled off at a low level (< 5 ppm) after about 10 d back on the untreated diet. Selenium levels in egg whites responded faster than levels in yolks to the females' consumption of treated and untreated diets.
Biodegradation of sucralose, a chlorinated carbohydrate, in samples of natural environments
Authors: Labare Michael P. , Alexander Martin
Published: March 2010

Measurements were made of the biodegradation of 4-chloro-4-deoxy-α, D-galactopyranosyl-1,6-dichloro-1,6-dideoxy-β, D-fructofuranoside (sucralose) in samples of several natural environments. This chlorinated carbohydrate, which represents a new class of artificial sweeteners, was extensively transformed to CO2 in four mineral soils with pH values of 4.9 to 7.2. Mineralization occurred at concentrations of 0.01 to 1,000 mg of sucralose per kilogram of soil, and the initial rates were a direct function of substrate concentration. At the lower concentrations, mineralization was initiated with no detectable acclimation period. Mineralization was not evident in soil under anaerobiosis. Mineralization occurred in lake sediments, sewage, and estuarine water but at lower rates and lesser extents than in soils. Little mineralization was evident in samples from oligotrophic, mesotrophic, and eutrophic lakes, the extent of mineralization being often less than the contamination level of the sucralose preparation. Sucralose degradation resulted from microbial activity because mineralization did not occur in sterilized environmental samples, and the addition of cycloheximide or streptomycin to soil significantly reduced mineralization. No bacterium could be isolated that was capable of utilizing sucralose as the sole carbon source. The data suggest that the biodegradation of sucralose is a cometabolic process.
Studies on the occurrence and distribution of wood smoke marker compounds in foggy atmospheres
Authors: Sagebiel John C. , Seiber James N.
Published: March 2010

Fog water and interstitial air samples were collected simultaneously and analyzed for methoxylated phenols, which have been previously reported as incomplete combustion products from wood lignin. The purposes of this study were to ascertain if these methoxylated phenols could be detected in fog sampled in residential areas and to determine the distribution of the compounds between fog droplets and interstitial air. The fog water was collected with a Teflon® filament fog collector and filtered through a 0.2-μm filter before extraction and GC analysis. Vapor samples were collected using a dichotomous sampler to separate fog droplets from interstitial air; the organic vapors were collected on polyurethane foam. Guaiacol, 4-methylguaiacol, and syringol were the most commonly found among the 16 methoxylated phenols confirmed in fog samples. The distributions between air and water approximately followed Henry's law, suggesting that previously reported enrichments into fog water are related to analyte hydrophobicity, described by either the octanol/water partition coefficient or the water solubility.
Bioaccumulation of PCBs by algae: Kinetics versus equilibrium
Authors: Swackhamer Deborah L. , Skoglund R.S.
Published: March 2010

The objectives of this study were to test the hypothesis that bioaccumulation of hydrophobic organic compounds (HOCs) by phytoplankton is correlated to the compound's octanol/water partition coefficient (Kow) in a predictive relationship in laboratory experiments, and to confirm these findings with field observations. In laboratory experiments we measured the uptake of 40 representative polychlorinated biphenyl (PCB) congeners over time under conditions that inhibited and allowed phytoplankton growth. Results indicated that the bioaccumulation process is consistent with partitioning from water into cell lipids but is slower than previously thought. The uptake of PCBs was slow relative to growth of phytoplankton, preventing the chemical from reaching thermodynamic equilibrium in algal cells under conditions promoting growth (nonwinter). Thus under non-winter field conditions, many PCB congeners never reach equilibrium concentrations. Food-chain models that assume equilibrium between HOCs and the primary trophic level could be inaccurate and may need to use a kinetic framework.
In vitro red blood cell assay for oxidant toxicity of petroleum oil
Authors: Couillard C.M. , Leighton F.A.
Published: March 2010

Petroleum oil has caused hemolytic anemia in birds and mammals. In birds, an oxidant damage on circulating red cells has been identified as the primary toxic effect of ingested petroleum oils. An in vitro red blood cell assay was developed to discriminate among the oxidant activities of different petroleum oils. The assay used rabbit red blood cells with a rat liver enzyme system and formation of methemoglobin was measured as an indicator of oxidant damage to the red cells. The assay was applied to five different petroleum oils and to naphthalene, a petroleum hydrocarbon known to cause hemolytic anemia. Different petroleum oils differed in their capacity to induce methemoglobin formation. Methemoglobin levels varied from 2.9% with Arabian light crude oil to 6.2% with South Louisiana crude oil. Naphthalene induced formation of up to 37% methemoglobin. Naphthalene and the five petroleum oils generated methemoglobin only in the presence of liver enzymes.
Toxicity of sediments containing atrazine and carbofuran to larvae of the midge Chironomus tentans
Authors: Douglas W. Scott , McIntosh Alan , Clausen John C.
Published: March 2010

Field and laboratory tests were conducted to determine the 10-d toxicity of atrazine and carbofuran to larvae of the midge Chironomus tentans. The pesticides were first spiked onto a clean control sediment, and the midges were exposed to atrazine, carbofuran, or mixtures of both compounds. Laboratory toxicity tests with carbofuran yielded LC50s of 20.5 μg/kg bound to sediment and 11.8 μg/L dissolved in interstitial water. Slight but statistically significant toxicity was detected at the highest tested concentration of atrazine (9,000 μg/kg, bound). Toxic interaction between the two pesticides was assessed using all possible combinations of four concentrations of both pesticides spiked onto clean sediments. Analysis of variance was used to determine if greater than or less than additive effects occurred when both pesticides were present. No toxic interaction between atrazine and carbofuran was detected. Based on laboratory findings, it was predicted that edge-of-field runoff could be toxic to midge larvae if concentrations of carbofuran exceeded 5 μg/kg. To test these predictions, actual edge-of-field runoff was collected from a cornfield receiving atrazine and carbofuran at recommended rates and the suspended sediments used in a toxicity test. Edge-of-field runoff containing carbofuran at 186 μg/kg was acutely toxic to midge larvae.
Cellular biomarkers for measuring toxicity of xenobiotics: Effects of polychlorinated biphenyls on earthworm Lumbricus terrestris coelomocytes
Authors: Goven Arthur J. , Fitzpatrick Lloyd C. , Eyambe George S. , Venables Barney J. , Cooper Edwin L.
Published: March 2010

Acute toxicity in earthworms (Lumbricus terrestris) was assayed immediately after 5-d filter paper exposure to the polychlorinated biphenyl (PCB) Aroclor 1254, using coelomocyte viability, total extruded cell counts (ECC), differential cell counts (DCC), and formation of erythrocyte (ER) and secretory rosettes (SR) with, and phagocytosis of, antigenic rabbit red blood cells (RRBC). Chronic toxicity was assayed using rates by which earthworms replaced viable immunoactive coelomocytes, removed noninvasively immediately after exposure, over an 18-week depuration period. All cytological parameters, except ECC, were acutely affected immediately after exposure, when tissue concentrations were (X ± se) 91.2 ± 8.19 μg PCB per gram dry mass. Replacement of viable immunoactive coelomocytes occurred within six weeks in unexposed control earthworms. Exposed earthworms showed significant alteration in viability, ECC, DCC, ER, and SR formation, and phagocytosis at 6 and 12 weeks when PCB tissue concentrations were 41 ± 0.31 and 30.2 ± 0.88 μg/g dry mass, respectively. Replacement of extruded coelomocytes with normal DCC of viable immunocompetent cells was not observed until week 18, when PCB had decreased to 15.7 ± 0.83 μg/g dry mass. Low inherent natural variability in coelomocyte viability, ECC, DCC, rosette formation, and phagocytosis, and their sensitivity to sublethal PCB body burdens, indicated that earthworm coelomocytes have potential as nonmammalian biomarkers for assaying acute and chronic sublethal toxicity of xenobiotics.
Caged and wild fish: Induction of hepatic cytochrome P-450 (CYP1A1) as an environmental biomonitor
Authors: Haasch Mary L. , Lech John J. , Prince Ruth , Cooper Keith R. , Wejksnora Peter J.
Published: March 2010

Hepatic monooxygenase activity can be induced by many different environmental chemical contaminants, and measurement of this activity has been proposed as an environmental biomonitor. Using in situ caged catfish and largemouth bass, and collected wild killifish, environmental induction of hepatic CYP1A1 was investigated using catalytic enzyme assays, regiospecific metabolism, immunodetection, and nucleic acid hybridization. The purpose of these studies was to evaluate these techniques for detection of CYP1A1 induction as a potential environmental biomonitor of environmental chemical contamination. Exposure of catfish in cages to polyaromatic hydrocarbon- (PAH-) and polychlorinated biphenyl- (PCB-) contaminated river water for two, four, or six weeks resulted in fourfold increases in ethoxyresorufin-O-deethylase (EROD) activity and three- and fivefold increases in immunoreactive CYP1A1 protein and hybridizable CYP1A1 mRNA, respectively, when compared to laboratory water control values. Hybridizable CYP1A1 mRNA in caged largemouth bass increased 5.1-fold at 1 d of exposure. Caged largemouth bass had 5-, 1.4-, and 0.8-fold increases at 3 d and 6-, 2.4-, 0.4-fold increases at 7 d of river water exposure in EROD, immunoreactive CYP1A1 protein, and CYP1A1 mRNA, respectively, when compared to laboratory water control values. Livers of killifish from a 2,3,7,8-tetrachlorodibenzo-p-dioxin-contaminated area had threefold higher EROD activity and similarly elevated immunoreactive CYP1A1 protein, a two- to fourfold increase in CYP1A1 mRNA, and a four- to eightfold increase in 6β-hydroxyprogesterone activity, when compared to killifish livers sampled from a “clean” site. These results indicate that catalytic activity measurements, immunodetection, and nucleic acid hybridization may be used to detect environmental hepatic CYP1A1 induction in fish, and may be useful for the biomonitoring or screening of selected environments for chemical contamination.
Benzo[a]pyrene metabolism and excretion in white suckers with chronic liver diseases
Authors: Smith Ian R. , Kirby Gordon M. , Ferguson Hugh W. , Hayes M. Anthony
Published: March 2010

Wild white suckers (Catostomus commersoni) with diseased bile ducts excreted an oral dose of benzo[a]pyrene (BaP) into their bile as glucuronide, glutathione, and sulfo-conjugates at twice the rate (16.76 nmol/h) of an unaffected reference population (7.52 nmol/h). BaP-hydroxylase (10% higher in the diseased population), glutathione-S-transferase (similar), or uridine-5′-diphos-phoglucuronic acid transferase (50% lower) levels did not correlate with these excretion rates. Metabolite levels were 57% higher in the liver of affected suckers than those in the liver of reference suckers, which might be due to bile retention within the diseased bile ducts. The bile duct disease affecting white suckers does not appear to restrict the metabolism and excretion of BaP.
Synthesis and accumulation of stress proteins in tissues of arsenite-exposed fathead minnows (Pimephales promelas)
Authors: Dyer Scott D. , Brooks G. Lance , Dickson Kenneth L. , Zimmerman Earl G. , Sanders Brenda M.
Published: March 2010

The stress protein response (SPR) is a ubiquitous, protective, and defensive mechanism that enables cells to tolerate environmental perturbations. Induction of the SPR involves the increased transcription of stress protein genes, the products of which function in protein folding, multimeric protein assembly, receptor interactions, and heme catabolism, and so forth. The potential of this response as an indicator of water quality was evaluated in gill and striated muscle tissues of fathead minnows (Pimephales promelas) exposed to a wide range of concentrations of sodium arsenite for various lengths of time.

The SPR in gill was elicited rapidly, occurring by 2 h exposure at 25 mg/L. The response was tissue specific. In gill, synthesis and accumulation rates of 20-, 40-, 70-, 72-, and 74-kD proteins were significantly increased, compared to controls. In muscle, 20-, 30-, 68-, 70-, and 90-kD proteins also showed significantly increased syntheses and accumulations. Synthesis and accumulation rates of arsenite-induced proteins 20-, 70-, 72-, and 74-kD in gill were significantly correlated with mortality. However, in striated muscle, only the 70-kD was significantly correlated with mortality.
An evaluation of the toxicity of various forms of chlorine to Ceriodaphnia dubia
Authors: Taylor P.A.
Published: March 2010

Ambient toxicity tests at 15 sites on five small streams that receive discharges from Oak Ridge National Laboratory (TN) showed that chlorine (mostly from once-through cooling water) was an important toxicant; however, there was not a good correlation between chlorine concentration and toxicity to Ceriodaphnia dubia in the ambient tests. To better understand the toxicity of chlorine, its various forms (hypochlorite ion, hypochlorous acid, monochloramine, and dichloramine) were tested individually. Standard Ceriodaphnia dubia acute toxicity tests (static, 24 h, with added food) showed that the chloramines were very toxic (LC50 < 0.02 mg/L) but that free chlorine (hypochlorous acid and hypochlorite ion) was much less toxic (LC50s of 0.14 and 0.08 mg/L, respectively). Chlorine decay measurements in the toxicity test solutions showed that free chlorine reacts very rapidly (<1 min) with the Ceriodaphnia dubia food (a mixture of digested trout chow, yeast, and Cerophylř) added to the solutions, so the standard toxicity test measured the toxicity of chlorinated food rather than the toxicity of free chlorine. Static tests without food showed LC50s of 0.012 mg/L for monochloramine, 0.016 mg/L for dichloramine, 0.035 mg/L for hypochlorous acid, and 0.048 mg/L for hypochlorite ion; however, the free chlorine still decayed rapidly (< 7 h) in the test solution. Continuous-flow toxicity tests showed that free chlorine is more toxic than the chloramines, with LC50s of 0.005 mg/L for hypochlorous acid, 0.006 mg/L for hypochlorite ion, 0.016 for monochloramine, and 0.027 mg/L for dichloramine. The LC50s for hypochlorous acid and hypochlorite ion are substantially below the U.S. Environmental Protection Agency's 4-d average water-quality criterion for chlorine of 0.011 mg/L
Sublethal narcosis and population persistence: A modeling study on growth effects
Authors: Hallam Thomas G. , Canziani Graciela Ana , Lassiter Ray R.
Published: March 2010

This study of a Daphnia population model suggests that sublethal effects of nonpolar narcotics on growth of individual organisms can result in ultimate extinction of the population at chronic chemical concentrations near the effect concentration that leads to a 50% reduction in individual growth (the 16-d EC50 for growth). A quantitative dose-response relationship (QDRR)—a population extinction threshold, relating the minimal chronic chemical concentration that yields population persistence and the octanol/water partition coefficient (Kow)—is generated from numerical simulation studies of a Daphnia population model. The transition from population persistence to extinction is examined in terms of density functions in the lipid, structure, and age variables associated with models of individual daphnids. The densities of populations undergoing transition from persistence to extinction due to increased toxicity suggest that critically stressed populations are age-bimodal with a component of old, large individuals and a component of small, nonreproductive individuals. The populations that persist near the threshold for extinction are unexpectedly diverse in age density and consist of relatively small individuals.
Induction of cytochrome P450 1A in fish treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin or chemically contaminated sediment
Authors: van der Weiden Martine E.J. , Seinen Willem , van Den Berg Martin , Celander Malin , Föurlin Lars , Goksøsyr Anders
Published: March 2010

Mirror carp were exposed to Rotterdam Harbor sediment, highly contaminated with polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and polychlorobiphenyls (PCBs) (0.5 μg 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] equivalents per kilogram dry weight). In two additional separate experiments rainbow trout (Oncorhynchus mykiss) and mirror carp (Cyprinus carpio) received a single intraperitoneal injection of approximately 0.01, 0.03, 0.06, 0.3, 0.6, or 3.0 μg TCDD per kilogram body weight. In all three experiments induction of hepatic P450 1A was measured with immunochemical and enzymatic methods. The polyclonal antibodies anticod (Gadus morhua), anti-perch (Perca fluviatilis), and anti-rainbow trout P450 1A all cross-reacted with the P450 1A orthologue of the carp and rainbow trout. In most cases high correlations were found between 7-ethoxyresorufin O-deethylation (EROD) activity and cytochrome P450 1A protein contents, the latter measured by the enzyme-linked immunosorbent assay (ELISA) and protein blot methods. However, the correlations between EROD activity and P450 1A protein levels were higher within the separate sampling periods (i.e., 3, 6, and 12 weeks after dosage) than with the total data set, especially in the dose-effect study with the rainbow trout. This was probably caused by a difference in time-dependent relationships between P450 1A protein content and EROD enzyme activity: 12 weeks after dosage the P450 1A protein was still increased, although EROD activity had returned to background level. In addition, there were higher correlations of the EROD activity and P450 1A protein content with total P450 content in rainbow trout and carp treated with a single dose of TCDD, than with total P450 content in carp exposed to contaminated sediment. In our study, the ELISA method appeared to be more useful than the protein blot technique, because the ELISA is faster and has higher reproducibility. In addition, in all our experiments EROD activity showed a higher induction than the P450 1A protein, indicating a higher sensitivity of the EROD assay. Our results strongly indicated that determination of the P450 1A protein content and EROD activity provides complementary information. Thus we recommended the use of both the ELISA and the EROD activity assay in order to understand the nature of P450 1A induction.
Reductive dechlorination of aroclor 1242 in anaerobic sediments: Pattern, rate and concentration dependence
Authors: Rhee G.-Yull , Bush B. , Sokol R.C. , Bethoney C.M. , DeNucci A. , Oh H.-M.
Published: March 2010

Anaerobic biotransformation of polychlorinated biphenyls of Hudson River sediment microorganisms was investigated using the commercial mixture Aroclor 1242 in the laboratory at six different concentrations: 120, 300, 500, 800, 1,000, and 1,500 μg/g (on a sediment dry-weight basis). Dechlorination was concentration dependent. No change in congener composition was found at 1,000 and 1,500 μg/g during seven months of incubation, but significant shifts were observed in sediments with concentrations below 800 μg/g. A mass balance of the transformation indicated that, despite the shifts, the total molar concentration remained the same. An optimum concentration, based on the decrease of Cl per biphenyl, was 500 μg/g, but based on Cl removed per gram sediment it had a range from 500 to 800 μg/g. Dechlorination (total Cl removed per biphenyl) at 300 and 500 μg/g appeared to be first order, with rate constants of —0.039 and —0.059 per month, respectively. The rate also varied with the substitution position; it was faster for m-Cl, followed by p-Cl, but no o-Cl was removed. However, the faster rate of m-dechlorination in Aroclor 1242 was probably due to a high concentration of congeners in the Aroclor with Cl substitution patterns favoring its removal, rather than the meta-position itself.
Toxicokinetics of halogenated benzenes in fish: Lethal body burden as a toxicological end point
Authors: Sum Dick T.H.M. , Schipper Maria , Opperhuizen Antoon
Published: March 2010

The lethal body burden (LBB), the whole-body concentration in millimoles per kilogram at time of death or immobilization, and the LC50 of dihalogenated (F, Cl, Br) benzenes were measured. Except for 1,4-difluorobenzene in guppy (28 mmol kg−1), LBBs varied between 2 and 8 mmol kg−1. The LBBs of the chemicals in guppies were not significantly different from those in fathead minnows. LC50 values varied between 0.54 and 41 μmol L−1 and were inversely related to the octanol/water partition coefficient, Kow. To estimate the risk of a compound to fish, the LBB requires the exposure concentration in combination with a first-order one-compartment bioaccumulation model. Therefore, the time of death or the time of immobility, and bioconcentration parameters such as the uptake rate constant (k1) and the elimination rate constant (k2), were determined. For both species, k1 values of the chlorinated benzenes were smaller than those of the brominated compounds and k2 values decreased with increasing hydrophobicity. The lipid-normalized bioaccumulation factors (KL's) were linearly related to Kow.
Regression analysis of log-transformed data: Statistical bias and its correction
Authors: Newman Michael C.
Published: March 2010

Power and exponential models are used frequently in environmental chemistry and toxicology. Such models can generate biased predictions if derived with least-squares, linear regression of log-transformed variables. An easily calculated but seldom used estimate of bias can enhance the accuracy of subsequent predictions. This prediction bias and means of correcting it are presented, along with several examples.