bluuebunny/crossref_metadata_2025 huggingface dataset:
Diazinon dissipation from vegetation, occurrence in earthworms, and presence in avian gastrointestinal tracts collected from apple orchards following D-Z-N® 50W application
Authors: Cobb George P , Mellott Ron , Brewer Larry W , Bens Catherine M , Kendall Ronald J
Published: March 2010

Comprehensive residue determinations weremade in biota inhabiting orchards receiving diazinon application as part of ecotoxicology studies in the United States. The states of Washington and Pennsylvania served as study areas representing different climatic and agricultural practices. Mean diazinon application was 3.0 to 3.1 kg a.i./ha in the orchards, and a subsequent exponential reduction in concentrations occurred on vegetation. Diazinon was present in earthworms following application, and 23 of 25 avian species evaluated in treatment orchards contained diazinon in their gastrointestinal (GI) tracts. Diazinon residues were present in 18 of the 20 avian species that were represented by more than one sample. Quantifiable residues were present in 17 of the bird species. Earthworms from Pennsylvania orchards contained more frequent and higher diazinon concentrations than did earthworms from Washington orchards (p < 0.005). Passerine exposure to diazinon was not different when comparing diazinon concentrations in individual species between the two geographic regions (0.23 < p < 0.06). Exposures were different for American robins and European starlings (p = 0.03) in Washington and for Northern cardinals and European starlings (p = 0.03) in Pennsylvania. Residues in GI tracts suggest that lethal exposures were limited to the day of application and the 4 d following application. Data indicate that, under conditions of repeated diazinon application, ingestion of earthworms poses risks to passerines.
Effect of irradiance spectra on the photoinduced toxicity of three polycyclic aromatic hydrocarbons
Authors: Diamond Stephen A , Mount David R , Burkhard Lawrence P , Ankley Gerald T , Makynen Elizabeth A , Leonard Edward N
Published: March 2010

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events underlying phototoxicity. This suggests that variation in light spectra present in natural waters, arising from variation in dissolved organic carbon composition, is an important determinant of phototoxicity risk in specific, PAH-contaminated waterbodies. To quantify the effect of environmentally realistic variation in light spectra on toxicity, brine shrimp (Artemia salina) assays were conducted under various light spectra and with three PAHs (pyrene, fluoranthene, and anthracene) of known phototoxicity potential. In these spectral assays, the total ultraviolet light present was equivalent; only the spectral characteristics varied. Based on the absorbance spectra of these PAHs, it was predicted that toxicity, quantified using immobilization as the endpoint, would vary significantly among light spectra in pyrene assays, but not in anthracene assays, and that variation in toxicity in fluoranthene assays would be intermediate. The results supported these assumptions. In the pyrene exposures, the glass filter time to 50% population immobilization (IT50) (39.5 min) was 117% longer than the KCr filter IT50 (18.2 min). In the fluoranthene exposures, the glass filter IT50 (49.5 min) was 27% longer than the KCr filter IT50 (39.1 min). In the anthracene exposures, the glass filter IT50 (62.2 min) was not statistically different from the KCr filter IT50 (63.8 min). Comparison of these results with the results of assays conducted under neutral-density filters (that change intensity but not spectral distribution) demonstrate that multiplying spectral intensity by wavelength-specific absorbance accurately predicts relative photoinduced toxicity among the experimental treatments. These results indicate that quantifying the spectral characteristics of PAH-contaminated aquatic environments may be an important component of risk assessment at these sites.
Genotype and toxicity relationships amongHyalella azteca: I. Acute exposure to metals or low pH
Authors: Duan Yihao , Guttman Sheldon I , Oris James T , Bailer A John
Published: March 2010

Comparative genotype and toxin interactions at three polymorphic enzyme loci were examined in a laboratory population of amphipods (Hyalella azteca) during acute exposure to cadmium, zinc, copper, lead, or low pH. Significant toxin-genotype interactions were observed using logistic regression to model mortality in ten of 15 analyses. Both stressor-specific and nonspecific modes of selection were observed. In general, low pH selected for different genotypes than those selected by metals, especially zinc. Different modes of selection were also observed when amphipods were exposed to different metals. These results suggest that exposure to low pH would significantly reduce the ability of H. azteca to survive subsequent contamination by metals; exposure to stressors in the reverse order would also compromise a population's chance of survival. A genetic distance analysis showed that the magnitude of genetic differentiation consistently increased among survivors compared with that of the initial populations. These increases in genetic divergence estimates suggest that acute exposure to metals or low pH may have an evolutionarily significant impact on the species. They also suggest that both genotype frequency and genetic distance measures (based on allozyme data) may be used as bioindicators for environmental monitoring programs. Validation of such bioindicators requires an understanding of the population's genetic background, genetic structure, and history.
Multimedia level-III partitioning and residence times of xenobiotics in water-rich and water-poor environments
Authors: Breitkopf Cornelia , Kühne Ralph , Schüürmann Gerrit
Published: March 2010

The environmental fate of 10 compounds covering a wide range of intrinsic persistence and volatility is studied with a multimedia level-III fugacity model at two system temperatures (293 and 282 K) using water-rich and water-poor model environments and standard emission scenarios to air and water, respectively. The resultant level-III partitionings depend significantly on the entry mode and on the relative compartment sizes, and the variation with system temperature is more pronounced for polar compounds and when air is the primary discharge compartment. For example, the steady-state portion in soil of airborne phenol varies from 21 to 89%, whereas waterborne phenol resides in water at a rate of 100% in both water-rich and water-poor environments. For some compounds, the residence time (considering both advection and degradation) is substantially affected by intermedia transport processes such as rainfall. With airborne atrazine, the regional residence time is comparable to that of DDT and significantly greater than the ones of hexachlorobenzene, polychlorinated biphenyl 28, and lindane, although the latter have much longer media-specific half-lives and much greater hydrophobicity. The discussion includes detailed analyses of the compound properties and their impact on the level-III environmental fate.
Multivariate modeling of polychlorinated biphenyl–induced CYP1A activity in hepatocytes from three different species: Ranking scales and species differences
Authors: Andersson Patrik L , van der Burght Aafje S.A.M. , van den Berg Martin , Tysklind Mats
Published: March 2010

Cytochrome P4501A–induced activity of 20 selected polychlorinated biphenyls (PCBs) was evaluated by measuring ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase activities induced in the hepatocytes of cynomolgus monkeys, male castrated pigs, and chicken embryos. Quantitative structure-activity relationships have been established, including 52 physi-cochemical parameters and different measures of the dose-response curves. Relative effect potencies are predicted for the 154 tetra-to hepta-PCBs and reported for the most potent congeners according to both EC50 and maximal response values. Important physicochemical parameters of the PCBs as related to the modeled activity are parts of their ultraviolet absorption spectra, the Henry's law constant, the ionization potential, and the octanol-water partition coefficient. Interspecies differences were found in terms of varied sensitivity to different structural subgroups of the compounds. The chicken hepatocyte assay showed the most specific structure-activity relationship, with high activity for the non-ortho PCBs, whereas the pig hepatocytes responded even for some di- to tetra-ortho PCBs. An interspecies response, the principal induction potency, is presented for the 41 most potent PCBs. These responses showed strong correlation with the toxic equivalency factors and are likely to be useful in risk assessment of the compounds.
Comparative measures of the toxicity of component chemicals in aircraft deicing fluid
Authors: Cornell Jeffrey S , Pillard David A , Hernandez Mark T
Published: March 2010

Acraft deicingoperationsarea necessarypart of safe air travel, but release large quantities of aircraft deicing fluids (ADFs) to the environment. Effective measures to mitigate the environmental impacts of deicing operations are hindered because of the negative effects some ADF chemicals have on treatment systems and because of the poorly characterized toxicity of ADF components. This research investigated the contributions of environmentally significant concentrations of selected ADF components to the toxicity of ADF-containing waste streams, and to the inhibition of biodegradation of propylene glycol (PG), the most important component of ADF. The component chemicals studied were PG, the corrosion inhibitor 4(5)-methylbenzotriazole (MeBT; common name: tolyltriazole), and proprietary mixes of corrosion inhibitors, buffers, and surfactants referred to as the additive package or AdPack. Relative to PG alone, the different additives increased the toxicity of ADF and decreased PG biodegradation rates. In enrichments of soil microorganisms acclimated to ADF, the MeBT component significantly decreased cell growth rates and yields, and inhibited PG biodegradation to a greater extent than the AdPack. Microtox® tests indicated that MeBT is the ADF component most toxic to microorganisms. However, acute aquatic toxicity tests indicated that the AdPack components were more toxic than MeBT to Ceriodaphnia dubia and Pimephales promelas, although both components were more toxic than PG alone.
Apportionment of polycyclic aromatic hydrocarbon sources in lower Fox River, USA, sediments by a chemical mass balance model
Authors: Su Ming-Chien , Christensen Erik R , Karls Jay F , Kosuru Sailaja , Imamoglu Ipek
Published: March 2010

Four sediment cores were collected from the lower Fox River, Wisconsin, USA, to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) using a chemical mass balance model. The cores, which were obtained in 1995 from areas close to Green Bay, Wisconsin, USA, had total PAH concentrations between 19.3 and 0.34 ppm. To determine historical trends of PAH inputs, 210Pb and 137Cs dating was used, and elemental carbon particle analysis was done to characterize particles from the combustion of coal, wood, and petroleum. Source fingerprints were taken from the literature. Our results indicate that coke oven emissions, highway dust, coal gasification, and wood burning are likely sources of PAHs in the lower Fox River. Coke oven emissions are in the range of 40 to 90% of total PAHs, and this fraction decreases from 1930 to 1990, except in core Fox River–A (FR-A). The overall highway dust (HWY) contribution is between 10 and 75%, and this fraction increases from 1930 to present, except in core FR-A. The wood burning (WB) contribution (i.e., wood burning or coal gasification) is less than 7% in cores FR-B, FR-C, and FR-D. In core FR-A, a maximum (≈23%) is found around 1960. The contribution of wood burning has changed from less than 6% in 1950 to between 3 and 10% in 1995. Evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene, with a half-life of approximately 0.5 years has been found at the site of core FR-D, which is the shallowest (1.1 m) of the four core sites.
Long-term fate and bioavailability of sediment-associated 2,3,7,8-tetrachlorodibenzofuran in littoral enclosures
Authors: Currie Robert S , Fairchild Wayne L , Holoka Morris H , Muir Derek C G
Published: March 2010

The fate and bioavailability of 2,3,7,8-tetrachlorodibenzofuran (TCDF; 4,6-tritium labeled) was examined over a 3-year (852-d) period in littoral enclosures (34 m3) in a small oligotrophic lake in the Experimental Lakes Area. Tetrachlorodibenzofuran was added as a single dose (10.4 g/34 m3) or as five small multiple additions over a 5-d period in a sediment slurry. Tetrachlorodibenzofuran was rapidly redistributed, mainly to bottom sediments (water column t½ ∼1.8 d), reflecting removal on settling particles. Between 0 and 120 d, 80 to 90% of TCDF in the water column was associated with particles (>1 μm). The highest concentration of TCDF in suspended particles was consistently observed in the smallest size fraction (0.22–1 μm) at 326 to 464 d posttreatment. Mode of addition had no effect on TCDF concentrations in water (unfiltered) or surficial sediments (0–2 cm) or pore waters throughout the experiment. Mean TCDF concentrations in surficial sediment (0–120 d) were 1,830 ± 1,180 pg/g (organic carbon [OC] basis), whereas they averaged 1,260 ± 596 pg/g OC from 318 to 851 d posttreatment. Increasing concentrations of TCDF in lower sediment layers at 852 d suggests that TCDF was either diffusing into the sediment or undergoing burial. Fugacity (f) calculations indicated that the TCDF in enclosures shifted from disequilibrium favoring the water column (days 0–9) to a disequilibrium with respect to bottom sediments (fwate/fsediment = 0.06–0.003) from day 21 onward. Initially, TCDF was more bioavailable to filtering and deposit feeders (mussels, Chironomidae, Hexagenia sp., and zooplankton) in enclosures receiving multiple additions; however, differences were rarely statistically significant. Concentrations of TCDF in all organisms were initially high, and they decreased in later sampling periods. Biota–sediment-accumulation factors (BSAFs) in mussels and crayfish were >1 in the early sampling periods, which reflected greater bioavailability of the added particle-borne TCDF. By 851 d, BSAFs had declined to 0.02 to 0.04, reflecting removal of TCDF from the water column and from surficial sediments.
A new method for measuring carbonate radical reactivity toward pesticides
Authors: Huang Jiping , Mabury Scott A
Published: March 2010

The carbonate radical is produced from the scavenging of the hydroxyl radical by carbonate/bicarbonate and is strongly electrophilic toward electron-rich compounds such as aromatic amine and sulfur-containing compounds. Carbonate radical reactivity (CO3⋅−) was measured by setting up a competition between a chemical of known reactivity and a compound with unknown reactivity toward CO3⋅−. The carbonate radical was produced using a novel method whereby KOONO (potassium peroxonitrite) was dissolved into 0.01 NaHCO3 solution initially producing a HO⋅, which was rapidly scavenged by HCO3⋅−, yielding CO3⋅− CO3⋅− production was monitored using a stopped-flow spectrometer at the absorption band for CO3⋅− of 600 nm. Results using this competition kinetic method indicated the second-order rate constants for substituted anilines corresponded to reference values with a relative error less than 10%. Using σpara+ values, the rate constants of substituted anilines at pH 9.0 correlated well (R2 = 0.98) with the Hammett equation yielding ρ = −0.89. To measure the reactivity of pesticides toward the carbonate radical, p-nitroaniline (PNA) was selected as the standard competitor. Of the nine pesticides tested, fenthion was the most reactive, followed by phorate, with rate constants above 107/M/s. Fluometuron and atrazine were of intermediate reactivity, and methyl parathion was one of the least reactive.
Dietary accumulation and quantitative structure-activity relationships for depuration and biotransformation of short (C10), medium (C14), and long (C18) carbon-chain polychlorinated alkanes by juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Fisk Aaron T , Tomy Gregg T , Cymbalisty Chris D , Muir Derek C G
Published: March 2010

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three [14C]-polychlorinated alkanes (PCAs) (C10H15.3Cl6.7, C14H23.3Cl6.7, and C18H31.4Cl6.6) at nominal concentrations of 1.5 and 15 μg/g for 40 d, followed by 160 d of clean food, to measure bioaccumulation parameters and biotransformation. These PCAs are identical in carbon-chain length and chlorine content to industrial chlorinated paraffin products, although their method of synthesis differs from that of chlorinated paraffin products. Half-lives ranged from 26 to 91 d, biomagnification factors ranged from 0.9 to 2.8, and both exhibited increasing trends with increasing carbon-chain length. Data from this work and others on PCAs were used to determine biotransformation rates and to examine quantitative structure-activity relationships for bioaccumulation and biotransformation. Quantitative structure-activity relationships developed for half-life and biomagnification factor showed positive linear relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log Kow. The PCA biotransformation rates (per day) ranged from −0.00028 to 8.4 and exhibited negative relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log Kow. Results suggest that PCAs with a total number of carbon and chlorine atoms between 22 and 30 are slowly, or are not, biotransformed in juvenile rainbow trout. Increasing carbon-chain length and chlorine content result in greater bioaccumulation of PCAs by reducing partition-based (i.e., diffusion) and metabolic (i.e., biotransformation) elimination processes. High bioaccumulation potential and low biotransformation rates of medium (C14-18) and long (C18-30) carbon-chain PCAs and highly chlorinated PCAs indicate that information is needed regarding the environmental concentrations of these PCAs in aquatic food chains.
Teeth as biomonitors of soft tissue mercury concentrations in beluga, Delphinapterus leucas
Authors: Outridge Peter M , Wagemann Rudolph , McNeely Roger
Published: March 2010

This paper reports relationships between bulk Hg concentrations in the tooth cementum and soft tssues of fee-living beluga (Delphinapterus leucas). Total Hg levels were determined in slivers of cementum using a solid-sample Hg analyzer, a recent advance in Hg analysis that avoids acid predigestion. Tooth Hg concentrations ranged up to about 350 ng/g dry weight and were significantly correlated with Hg levels in kidneys, liver, muscle, and muktuk (skin) and with the age of the animals. The Hg/Se ratio in liver, the organ with the highest Hg concentrations, may have been an important determinant of tooth Hg. At hepatic Hg/Se molar ratios ≥0.6, tooth Hg increased steeply, suggesting that Hg in teeth may reflect physiologically available Hg that was not bound in the liver and that was circulating in the bloodstream. This Hg/Se ratio was exceeded in most beluga aged ≥20 years. The results indicate that teeth can be used as biomonitors to reconstruct temporal and geographic trends in the soft tissue Hg concentrations of beluga, provided that the age structures of the different populations are known.
Slowly and very slowly desorbing organic compounds in sediments exhibit langmuir-type sorption
Authors: Cornelissen Gerard , Rigterink Henk , van Noort Paul C M , Govers Harrie A J
Published: March 2010

Desorption kinetics were determined for 1 2,4-trichlorobenzene (TCB), 13-dichlorobenzene (DCB), and trichloroeth-ylene (TCE) in a sediment at various concentrations. The desorption data were interpreted with a (nonmechanistic) first-order three-compartment model. In this way, separate sorption isotherms could be constructed for rapidly, slowly, and very slowly desorbing sorbate, respectively. Slowly desorbing (rate constant k ∼10−3/h) and very slowly desorbing (k = 10−4 to 10−5/h) sorbate exhibited nonlinear Langmuir-type sorption, with capacities on the order of 4.6 to 19 and 0.54 to 1.5 mmol/kg organic carbon (OC) and affinity constants of 0.18 to 41 and 32 to 272 L/mmol, respectively. The affinity constants increased with increasing sorbate hydrophobicity. Rapidly desorbing (k = 10−1/h) sorbate showed linear sorption isotherms, with log Koc (octanol–water partition coefficients) of 1.59 ± 0.12 (TCE), 2.03 ± 0.13 (DCB), and 3.13 ± 0.03 (TCB), respectively. These results confirm the hypothesis that desorption is rapid from linearly sorbing organic matter, whereas it is slow and very slow from nonlinearly sorbing sites. Furthermore, the results also demonstrate the applicability of the desorption kinetic method in terms of experimentally separating an overall Freundlich-like isotherm in linear and nonlinear isotherms.
Riverine endosulfan concentrations in the Namoi River, Australia: Link to cotton field runoff and macroinvertebrate population densities
Authors: Leonard Alex W , Hyne Ross V , Lim Richard P , Pablo Fleur , Van den Brink Paul J
Published: March 2010

Population densities of six dominant macroinvertebrate taxa (mayfly nymphs Jappa kutera, Atalophlebia sp., Tasma-nocoenis sp., Baetis sp. and the caddisfly larvae Cheumatopsyche sp. and Ecnomus sp.) were negatively correlated to total endosulfan concentrations in the Namoi River (New South Wales, Australia) in the 1995/96 and 1997/98 cotton growing seasons (November-March). Total endosulfan concentrations measured in solvent-filled polyethylene bags (passive samplers) at the exposed sites correlated with rainfall, suggesting that endosulfan entered the riverine environment in runoff from land. At the start of both surveys, in November 1995 and November 1997, there was no significant difference (p < 0.05) between the reference and exposed sites for both total endosulfan concentrations and mean population densities of the combined study taxa. This indicates distance downstream, which was negatively correlated with exposure, was not an important variable in explaining the significantly higher population densities in other months at the reference sites compared with those at sites subsequently exposed to increased (10–25-fold) total endosulfan concentrations. The multivariate analysis of the 1997/98 data with the principal response curves (PRC) method indicated that endosulfan explained a significant proportion (25%) of the variation in the total macroinvertebrate community. Principal components analysis (PCA) indicated other covariables were involved, including river discharge. River discharge was positively correlated to increased densities of the mayfly taxa at the reference sites in the 1995/96 survey, but these correlations were reduced to near zero, except for Baetis sp., in the 1997/98 survey.
Polychlorinated biphenyls, organochlorine pesticides, tris(4-chlorophenyl)methane, and tris(4-chlorophenyl)methanol in livers of small cetaceans stranded along Florida coastal waters, USA
Authors: Watanabe Mafumi , Kannan Kurunthachalam , Takahashi Atsushi , Loganathan Bommanna G , Odell Daniel K , Tanabe Shinsuke , Giesy John P
Published: March 2010

Concentrations of polychlorinated biphenyl congeners (PCBs) and organochlorine pesticides were determined in the livers of bottlenose dolphins, Atlantic spotted dolphins, and pygmy sperm whales found stranded along the coastal waters of Florida, USA, during 1989 to 1994. The PCBs were the most predominant contaminants followed in order by DDTs, chlordanes, tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMOH), hexachlorobenzene, and hexachlorocyclohexane isomers. Among the cetaceans analyzed, organochlorine concentrations were greatest in bottlenose dolphins followed by Atlantic spotted dolphins and pygmy sperm whales. Hexa- and heptachlorobiphenyls were the predominant PCB congeners found in the livers of dolphins. Patterns of relative concentrations of PCB congeners varied among individual bottlenose dolphins. A few individuals contained predominant concentrations of octa- (CB-199, 196/201) and nonachlorobiphenyl (CB-206, 208) congeners, which suggested exposure to the highly chlorinated PCB formulation, Aroclor® 1268, a contaminant at a coastal site in Georgia bordering northern Florida. The estimated 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) of coplanar PCBs in bottlenose dolphins were 170 to 18,000 pg/g, lipid weight (mean: 5,400 pg/g) with mono-ortho congeners 118, 105, and 156 contributing more than 80% of the TEQs. The ratios of CB-169 to CB-126 in cetacean livers were linearly related to total PCB concentrations, which suggested a strong induction of microsomal monooxygenase enzymes in the liver. The hepatic concentrations of TCPMe and TCPMOH in bottlenose dolphins and Atlantic spotted dolphins were greater than those in the blubber of marine mammals of various regions, which suggested the presence of sources for these chemicals along the Atlantic coast of Florida.
Early life-stage mortality in zebrafish (Danio rerio) following maternal exposure to polychlorinated biphenyls and estrogen
Authors: Westerlund Liselotte , Billsson Karin , Andersson Patrik L , Tysklind Mats , Olsson Per-Erik
Published: March 2010

In the present study, specific polychlorinated biphenyl (PCB) congeners were examined for embryo and early life stage mortality in zebrafish (Danio rerio). A set of eight PCBs and two hydroxylated PCBs and 17β-estradiol were tested. Of the compounds tested, 4′-OH-PCB30 (hydroxylated polychlorinated biphenyl) and PCB104 were found to be highly toxic to embryos following maternal exposure and transfer to the oocyte. It was also observed that 17β-estradiol exposure resulted in a high incidence of embryo mortality. Analysis of estrogen receptor levels during embryonic development showed increased mRNA (ribonucleic acid) levels from the 1K stage to 50% epiboly. Following injection of the different compounds, the estrogen receptor mRNA levels were also analyzed in adult male fish to determine if there was a correlation between embryo mortality and estrogenicity of the studied PCBs. The two PCBs that were highly embryo toxic were observed to be estrogenic.
Problems associated with an environmental assessment of organotins: Application to the organic polluted saladillo harbor (southern Spain)
Authors: Gómez-Ariza José Luis , Giraldez Inmaculada , Morales Emilio
Published: March 2010

Problems associated with assessing the environmental effects of organotin (OT) include extraction efficiency, whether to filter the water samples, effect of grain size of sediments, and mobility characteristics of OT species from sediments. This study considered these effects on the six OT species tributyltin, dibutyltin, monobutyltin, triphenyltin, diphenyltin, and monophenyltin in seawater and sediments collected from Saladillo Harbor, a representative enclosed area in southern Spain that receives inputs of both OTs and organic matter. Yields of organotin extracted from sediments with a high organic content by using dichloromethane were higher than those obtained by using pentane. Concentrations of butyltins were higher than those of phenyltins. A gradient was observed of decreasing butyltin concentrations in sediments from 280 ng Sn/g in the inner stations to 0.5 ng/g in the outer stations of the harbor. No dissolved organotin compounds were detected in the overlying seawater. Because OTs are related to the presence of organic matter, iron oxyhydroxides, and phylosilicates, they were strongly adsorbed onto particulate matter in both sediment and suspended matter. Low percentages of butyltins, ranging from undetectable to 0.54%, were released by extracting in unpolluted seawater at pH 8 and 5. Higher concentrations were found in finer sediments.
Evaluation of water-effect ratio methodology for establishing site-specific water quality criteria
Authors: Welsh Paul G , Lipton Joshua , Chapman Gary A
Published: March 2010

One approach outlined by the U.S. Environmental Protection Agency (U.S. EPA) for derivation of site-specific water quality criteria for metals in natural surface waters involves the development of water-effect ratios (WERs). This approach entails multiplying national water quality criteria by an experimentally derived WER, where the WER is defined as the ratio of the toxicity of the metal in the site water to the toxicity of the same metal in standard laboratory water. We discuss technical issues associated with test methods described in the U.S. EPA WER guidance document that may lead to inappropriate WERs. Critical issues include accounting for differences in calcium and magnesium concentrations (Ca:Mg ratios), alkalinity, and pH between site and laboratory waters; ensuring appropriate fish acclimation; and accounting for interspecies variability, multiple metals interactions, end-point variability, and temporal and spatial variability in the derivation of the WER. Failure to address these issues may have the unintended effect of deriving site-specific water quality criteria that are underprotective of aquatic life. We recommend that WER testing and future regulatory guidance for derivation of site-specific water quality criteria incorporate consideration of these potential confounding variables so that site-specific criteria can be established with greater confidence.
Chlorinated pesticide concentrations, with an emphasis on polychlorinated camphenes (toxaphenes), in relation to cytochrome P450 enzyme activities in harp seals (Phoca groenlandica) from the Barents Sea
Authors: Wolkers Hans , Burkow Ivan C , Lydersen Christian , Witkamp Renger F
Published: March 2010

Harp seals (Phoca groenlandica) from the Barents Sea were analyzed for blubber levels of polychlorinated biphenyls (PCBs), polychlorinated camphenes (PCCs; toxaphenes), DDT and its metabolites, hexachlorobenzene (HCB), hexachlorocyclo-hexanes (HCHs), and the cyclodiene pesticides, including dieldrin, endrin, and the chlordanes. Also, the hepatic cytochrome P450 (CYP) enzyme activities were measured to assess a possible relation between CYP activities and pesticide levels. Furthermore, the bioaccumulation potential and persistency of these compounds were evaluated. PCCs were the dominant contaminants, exceeding the PCB concentrations. Individual PCC congener levels (Tox 26 and 50) were fourfold greater than those in the Canadian Arctic and 20-fold greater than those in seals from the west coast of Svalbard, suggesting that the Barents Sea is exposed to PCCs by a local source. The biomagnification factor and the metabolic index were greatest for p,p-DDT, HCB, β-HCH, and the chlordanes trans-nonachlor and U82. The other pesticides showed lesser values, suggesting metabolism. The ethoxyresorufin-O-deethylation activity (CYP1A) was high and not correlated with any of the pesticides, whereas a high correlation (r2 adjusted > 50%) was found between the PCCs and testosterone 6-β hydroxylation activities (CYP3A). This suggests an induction of CYP3A-like activity by PCC exposure.
Dynamics of mercury in blood and feathers of great skuas
Authors: Bearhop Stuart , Ruxton Graeme D , Furness Robert W
Published: March 2010

Mercury dynamics in the blood and feathers of captive great skuas, Catharacta skua, were monitored over 56 weeks. Prior to the onset of molt, mercury intake was solely from their maintenance ration of sprats, Sprattus sprattus. For the first half of molt, in addition to mercury intake from sprats, birds were fed different doses of methylmercuric chloride weekly for 20 weeks. During the second half of molt, dosing was stopped and mercury intake was solely from sprats. Blood was sampled throughout the study and feather growth was monitored. Prior to the onset of molt, mercury concentrations increased over the first 51 to 71 d and appeared to level off after this period. Repeated dosing models based on mammalian pharmacokinetics were, in general, too simplistic to be applicable to the birds in the study. During molt, the elimination of mercury from the blood is probably best described by a three-compartment model. Mercury concentrations in feathers were significantly correlated with those in blood at the time of their growth, suggesting that blood and feathers reflect mercury intake over the same time period. Individuals varied in their ability to excrete ingested mercury into the feathers.
Frequencies of micronuclei in bank voles from zones of high radiation at Chornobyl, Ukraine
Authors: Rodgers Brenda E , Baker Robert J
Published: March 2010

A population of Clethrionomys glareolus (bank vole) from a highly radioactive area within the Chornobyl, Ukraine exclusion zone was sampled in June 1997 and in June and October 1998. Internal radiation doses from radiocesium were estimated to be as high as 8 rads/d. Total dose, which takes into account the internal dose from radiostrontium and the surrounding environment, was estimated to be 15 to 20 rads/d. In contrast, individuals from a reference population lying outside of the exclusion zone registered negligible levels of contamination. We used the micronucleus test in a double-blind study to analyze blood samples from 58 individuals. We scored more than 600,000 polychromatic erythrocytes (PCEs) but could not reject the null hypothesis that the frequency of micronucleated PCEs in voles exposed to radiation was equal to the frequency in unexposed voles. Results of our study stand in sharp contrast to earlier reports of increased frequencies of micronuclei in rodents exposed to fallout of the Chornobyl accident, but with radiation doses that were orders of magnitude lower than those reported here. Radioresistance and experimental methods are possible explanations for these differences in the results.
Exposure of pacific herring to weathered crude oil: Assessing effects on ova
Authors: Carls Mark G , Hose Jo Ellen , Thomas Robert E , Rice Stanley D
Published: March 2010

In order to determine if exposure to Exxon Valdez oil would adversely affect progeny, reproductively mature Pacific herring were confined in water contaminated with weathered crude oil. Progeny were generally not affected by a 16-d parental exposure to initial aqueous concentrations of ≤58 μg/L total polynuclear aromatic hydrocarbons (PAHs), yielding concentrations of up to 9.7 μg/g in ova. In contrast, previous research indicated that a 16-d direct exposure of herring eggs to similarly weathered oil was detrimental to developing embryos at total initial PAH concentrations of 9 μg/L. Progeny of exposed fish could have been insulated from toxic effects for two reasons. First, as an apparent result of partitioning and metabolism in parental tissues, lower concentrations and less toxic PAHs were preferentially accumulated by ova (primarily naphthalenes; 84–92%). Second, peak exposure concentrations occurred before cell differentiation. The opposite was true for directly exposed eggs; the more toxic multi-ring PAHs (e.g., phenanthrenes and chrysenes) and alkyl-substituted homologues were accumulated, and internal concentrations increased during cell division, differentiation, and organ development. Thus, Pacific herring embryos are more critically sensitive to oil pollution than are gametes.
Uncertainty factors in screening ecological risk assessments
Authors: Duke L Donald , Taggart Mitzy
Published: March 2010

The hazard quotient (HQ) method is commonly used in screening ecological risk assessments (ERAs) to estimate risk to wildlife at contaminated sites. Many ERAs use uncertainty factors (UFs) in the HQ calculation to incorporate uncertainty associated with predicting wildlife responses to contaminant exposure using laboratory toxicity data. The overall objective was to evaluate the current UF methodology as applied to screening ERAs in California, USA. Specific objectives included characterizing current UF methodology, evaluating the degree of conservatism in UFs as applied, and identifying limitations to the current approach. Twenty-four of 29 evaluated ERAs used the HQ approach; 23 of these used UFs in the HQ calculation. All 24 made interspecies extrapolations, and 21 compensated for its uncertainty, most using allometric adjustments and some using UFs. Most also incorporated uncertainty for same-species extrapolations. Twenty-one ERAs used UFs extrapolating from lowest observed adverse effect level (LOAEL) to no observed adverse effect level (NOAEL), and 18 used UFs extrapolating from subchronic to chronic exposure. Values and application of all UF types were inconsistent. Maximum cumulative UFs ranged from 10 to 3,000. Results suggest UF methodology is widely used but inconsistently applied and is not uniformly conservative relative to UFs recommended in regulatory guidelines and academic literature. The method is limited by lack of consensus among scientists, regulators, and practitioners about magnitudes, types, and conceptual underpinnings of the UF methodology.
Evaluation of the dutch environmental risk limits for metals by application of the added risk approach
Authors: Crommentuijn Trudie , Polder Marieke , Sijm Dick , de Bruijn Jack , van de Plassche Erik
Published: March 2010

Recently, environmental quality standards (EQSs) that include background concentrations for metals have been set in The Netherlands. These EQSs are based on environmental risk limits and applying the added risk approach. The added risk approach was developed to incorporate the background concentration of naturally occurring substances such as metals in environmental risk limits. The original approach discriminates between the bioavailable and unavailable fraction and calculates a permissible concentration that can be added to a background concentration, i.e., the maximum permissible addition (MPA). This MPA includes the effects caused by the bioavailable fraction of the background concentration. The new EQSs in The Netherlands assume the bioavailable fraction of background metals is mathematically equal to zero. The rationale for this assumption is that, from an environmental policy perspective, background-related effects that in reality do exist, are desirable because they may in theory lead to increased ecosystem variability or biodiversity. Moreover, there is little information on the bioavailability of background concentrations of metals. This paper presents a theoretical exercise in which the effects of varying background bioavailability on MPA values for cadmium, copper, lead, and zinc in water and soil are evaluated. The results show that, for these metals, bioavailability does not affect or only slightly affects the MPAs. Only the terrestrial MPAs for copper, lead, and zinc are sensitive to bioavailability. This minor influence of assumed percentage bioavailability on the MPAs, coupled with a policy-driven assumption that effects of background concentrations should be ignored, explain the current policy in The Netherlands that the bioavailability of background concentrations of metals should be assumed to be zero.
Thermodynamic estimation of vapor pressure for organophosphorus pesticides
Authors: Tsuzuki Manabu
Published: March 2010

A mthod was developed to estimate vapor pressure of organophosphorus compounds having various functional groups or bond types. The method requires only information on chemical structure of the compounds. The thermodynamic approach using the modified Watson equation was successfully applied to estimate the vapor pressures of organophosphorus pesticides, including phosphorothionates, phosphorodithioates, phosphoramidothioates, phosphates, phosphorothiolates, and phosphorodithiolates. The optimization of the Watson method was found essential for correctly estimating the vapor pressures of organophosphorus compounds, as were the adequate molar refraction of phosphorus atoms in the Eisenlohr correlation and the introduction of an empirical constant for the nitro group in Meissner's equation. The number of possible hydrogen bond sites was found to improve the accuracy of estimated vapor pressures, especially for pesticides possessing the P=O moiety. Our modified Watson equation was used to successfully elucidate the vapor pressure of pesticides ranging from 10−5 to 101 Pa at 298 K and could be used to correctly predict the vapor pressures of other organophosphorus pesticides not utilized in the analysis.
Release of polycyclic aromatic hydrocarbons from contaminated soils by surfactant and remediation of this effluent byPenicilliumspp
Authors: Pinto Linda J , Moore Margo M
Published: March 2010

Studies in which surfactants have been employed to increase the bioavailability of soil-bound polycyclic aromatic hydrocarbons (PAHs) have not yielded consistent results. Surfactant mobilization of high molecular weight (MW) PAHs from contaminated soils has not been extensively studied; therefore, the purpose of this research was to compare the extent of release of freshly added high MW 14C-PAH with aged PAH from four different PAH-contaminated soils using a nonionic detergent, Tween 80, and to determine whether Tween 80-solubilized 14C-PAH in soil washings could be degraded by indigenous microorganisms or by added Penicillium spp. Only very high concentrations of Tween 80 (>1,000 times the critical micelle concentration [CMC] for 3 of 4 soils) were able to mobilize bound 14C-pyrene, -chrysene, and -benzo[a]pyrene. The concentration of surfactant required to release 50% of bound 14C-PAH (the SC50 value) ranged from 5 to 30 g/L depending on soil type; a modest correlation was found (0.512) between the fraction of organic carbon in the soil and the SC50 value. At 104 × CMC, Tween 80 released an average of 75% of bound 14C-PAH and 64% of the aged PAH, indicating that the 14C-PAH release only slightly overestimated PAH mobilization from weathered soil. An exception was one soil that had been previously remediated in which <30% of the PAHs were released. The PAH structure had a negligible effect on the mobilization by surfactant because the solubilization curves for all three PAHs were very similar. Tween 80-solubilized 14C-pyrene readsorbed to soil when the surfactant concentration dropped below 103 × CMC. Greater than 90% of the 14C-pyrene in the soil washing effluent could be removed by the addition of spores of active PAH-oxidizing Penicillium spp. plus nutrients. In contrast, <10% of 14C-pyrene was oxidized by the indigenous soil bacteria under the same conditions.
Correlation of measures of ambient toxicity and fish community diversity in a Chesapeake Bay Tributary, Maryland, USA: A biological, chemical, and geological assessment
Authors: Hartwell S Ian , Alden Ray W , Wright David A , Ailstock Steven , Kerhin Randy
Published: March 2010

A battery of water column and sediment toxicity bioassays measuring lethal and sublethal endpoints were employed with fish, invertebrates, vascular plants, and bacteria. Monthly water column bioassays were conducted with water from three stations in the South River, Maryland, USA, and from a reference station in the Wicomico River (Maryland, USA). Sediment bioassays were conducted with five discrete samples taken from each station. Water column assays indicated low-level effects at the upstream stations in the South River. Animal species demonstrated higher responses than did plants. Chemical analyses revealed only trace levels of heavy metals. Sediment in the upper stations of the South River demonstrated significant toxicity to animal but not plant test species. Sediment chemistry indicated elevated levels of heavy metals and polycyclic aromatic hydrocarbons. The sediments are enriched with chromium, copper, iron, manganese, cadmium, and lead—above normalized background geochemical ratios. The toxicological risk ranking model identified a strong gradient from upstream to downstream. Toxicological risk scores for the downstream station in the South River were comparable to those for the reference station. The major source of contaminants in the South River is probably derived from a multitude of non–point sources associated with urbanization within the watershed. The upper stations are in a zone of deposition of riverine material, whereas the downstream station is dominated by open Chesapeake Bay dynamics.
Chronic toxicity of energetic compounds in soil determined using the earthworm (Eisenia andrei) reproduction test
Authors: Robidoux Pierre Yves , Svendsen Claus , Caumartin Jean , Hawari Jalal , Ampleman Guy , Thiboutot Sonia , Weeks Jason M , Sunahara Geoffrey I
Published: March 2010

Earthworm survival tests are commonly used in terrestrial ecotoxicology to assess the toxicity of compounds in soil. Earthworm (Eisenia andrei) reproduction tests were used to assess the sublethal and chronic effects of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5,7-triazacyclohexane (RDX). Effects on reproduction parameters (total number of cocoons, number of hatched cocoons, number of juveniles, juvenile biomass, and hatchability) were measured in TNT- and RDX-spiked artificial soil. For TNT, the lowest-observed-effect concentration (LOEC) was 110 mg/kg dry soil, and the no-observed-effect concentration (NOEC) was 55 mg/kg. For the RDX-spiked soil, the LOEC was 95 mg/kg dry soil, and the NOEC was <95 mg/kg. The growth of adult worms was also reduced when exposed to TNT-spiked soil at the highest tested concentration (881 mg/kg dry soil). Taken together, data analysis showed that the number of juveniles was strongly correlated with the number of cocoons but poorly correlated with the growth of adults. This information could permit one to optimize the application of the Eisenia sp. reproduction assay when used as a sublethal effect assessment tool for TNT- or RDX-contaminated soils.
Field assessment of toxic effects on reproduction in the earthworms Aporrectodea longa and Aporrectodea rosea
Authors: Holmstrup Martin
Published: March 2010

The aim of the present study was to estimate the in situ cocoon production in grassland of two earthworm species, Aporrectodea longa and A. rosea, in relation to application dose of Benomyl. The method used to estimate cocoon production was based on a detailed knowledge of the influence of temperature on development [R(T)] of earthworm cocoons, including the two species in this study. Soil temperature was measured throughout the study (May 5-June 6, 1997), and on June 6, the density of cocoons was estimated. The sampled cocoons were incubated in the laboratory and their hatching distribution was recorded. Based on R(T), the average development time in the field of cocoons produced on May 5 was predicted, and the hatched cocoons could thus be scored as either produced during the study period or before. This made it possible to estimate the density of cocoons produced during the study. The density of adults was also estimated by soil sampling during the study, and finally the reproductive rate could be calculated as density of cocoons divided by density of adults. In control plots, the reproduction of A. longa was estimated to be 2.5 ± 0.7 (mean ± SEM; n = 4) viable cocoons/adult during the 32-d study. In plots treated with 0.5 and 1.0 kg Benomyl (active ingredient [AI])/ha, a 70% reduction of the reproductive rate was observed, but this was only statistically significant at the highest dose. In control plots, the reproductive rate of A. rosea was estimated to be 6.05 ± 0.8 cocoons/adult during the study. Also in this species, there was a drastic decrease in reproduction, about 40% at both doses, due to Benomyl application. The results obtained in this field study were compared with results from laboratory reproduction tests with other earthworm species. There was good agreement between effects of Benomyl on reproduction in the laboratory and in the field. These results therefore suggest that standardized laboratory tests provide a reasonable prediction of the effect in the field.