bluuebunny/crossref_metadata_2025 huggingface dataset:
Feeding the mummichog (Fundulus heteroclitus) a diet spiked with non-ortho- and mono-ortho-substituted Polychlorinated biphenyls: Accumulation and effects
Authors: Gutjahr-Gobell Ruth E , Black Dianne E , Mills Lesley J , Pruell Richard J , Taplin Bryan K , Jayaraman Saroja
Published: March 2010

A laboratory model was developed to predict exposure effects in the field. Accumulation of non-ortho- and mono-ortho-substituted PCBs in liver tissue and their effects on mummichogs (Fundulus heteroclitus) were investigated. An artificial diet spiked with a mixture of eight PCB congeners was fed to mummichogs in the laboratory. Ratios of the congeners were similar to those measured in livers of mummichogs indigenous to the PCB Superfund site, New Bedford Harbor, Massachusetts, USA. Nominal dietary concentrations were high (54.3 μg/g wet body weight), medium (10.9 μg/g), low (2.2 μg/g), and a control. Accumulation of PCBs was consistent with exposure; however, lower levels of congener 77 were detected in liver tissue (0.2–0.8% of total PCBs) than in the spiked diets (3.3–4.6%). Significant (p ≤ 0.05) mortality occurred in mummichogs fed high and medium doses relative to the control. Mortality was higher and growth was lower with increasing toxic equivalent concentration of dietary PCB concentration and accumulation of PCBs in liver tissue. Mummichogs exhibited an exposure response in congener accumulation and biological effects with increasing dietary PCB concentration. Unlike fish from New Bedford Harbor, clean fish exposed to PCBs appear to have either slower uptake or higher metabolism of congener 77, indicating possible adaptation of mummichogs inhabiting polluted environments.
Bird response to grit and pesticide granule characteristics: Implications for risk assessment and risk reduction
Authors: Stafford Tamara R , Best Louis B
Published: March 2010

Granular pesticides (insecticides and nematicides) pose a hazard for birds because of the potential for birds to ingest the granules. Avian risk from granular pesticides is currently assessed by using a U.S. Environmental Protection Agency risk index based on the acute toxicity of the pesticide, the pesticide concentration on the granules, and the number of granules available on the soil surface after application (LD50/ft2). Recent evaluations have demonstrated that avian response to pesticide granules as a source of grit also can influence exposure to pesticide granules; such information should be included in the risk assessment process. Herein we review the limitations of the current risk assessment process and summarize the extant information regarding bird response to grit and granule characteristics (i.e., granule carrier type, color, size, shape, and surface texture) and pesticide load per granule. Suggestions are made for assessing and reducing avian risk from granular pesticides by testing granular formulations against standards for various granule characteristics and by using frequency distributions of avian responses to granules. Granule characteristics selected as standards should be similar to grit used by free-ranging birds (e.g., silica particles, earth-tone hues). Comparisons of granular formulations against the standards would demonstrate the potential for birds to consume pesticide granules as grit, relative to naturally occurring particles. Frequency distributions constructed for grit sizes used by birds and gizzard grit counts can be used to estimate the effect of granule size and pesticide load per granule, respectively, on avian risk. Because bird response to pesticide granules is highly variable, we recommend using probabilistic approaches when assessing avian risk from pesticide granules to account for the ranges of response.
Mercury contamination in free-ranging great egret nestlings (Ardea albus) from Southern Florida, USA
Authors: Sepúlveda María S , Frederick Peter C , Spalding Marilyn G , Williams Gary E
Published: March 2010

Between March and June of 1994 and 1995, mercury (Hg) concentrations were determined from 393 blood and 164 growing scapular feathers from 252 great egret nestlings (Ardea albus). Nestlings came from eight colonies located in Water Conservation Area 3 in the Everglades region in southern Florida. The ages of these birds ranged from 1 to 44 d (bill length 1.1 to 10.2 cm). Mercury concentrations in blood and feathers of first-hatched great egret nestlings sampled during 1994 averaged 1.2 μg/g (range = 0.07–3.9) wet weight and 16 μg/g (4.5–40) dry weight, respectively. During 1995, first-hatched chicks had blood and feather Hg concentrations that averaged 0.8 μg/g (0.2–1.7) and 9.7 μg/g (2.3–26), respectively. In both years, Hg concentrations in blood and feathers were significantly correlated, and a significant correlation also was found between Hg in blood and age of the chicks. Blood and feather Hg concentrations differed significantly between years, with higher concentrations during 1994. Birds from JW1 and L67 colonies had the highest concentrations of Hg in blood and feathers. Mercury concentrations did not differ between chicks of different hatch order. Mercury in feathers of great egret nestlings from southern Florida are approximately six times higher when compared to feather Hg concentrations of nestling wading birds sampled elsewhere.
Effects of resin acids on hepatocyte pH in rainbow trout (Oncorhynchus mykiss)
Authors: Nikinmaa Mikko , Wickström Charlotta , Lilius Henrik , Isomaa Boris , Råbergh Christina
Published: March 2010

We investigated the effects of two resin acids, isopimaric acid and dehydroabietic acid, which are both important components of wood industry effluents, on the intracellular pH of rainbow trout (Oncorhynchus mykiss) hepatocytes. In HEPES-buffered medium, at an extracellular pH of 7.7, the intracellular pH of untreated hepatocytes was 7.84 ± 0.043 (mean ± SEM, n = 40). The major pathway for pH regulation was calcium-activated sodium/proton exchange, as indicated by the facts that the pH decreased when sodium was removed from the medium, when the cells were incubated in the medium containing 5-(N,N-methyl isobutyl)-amiloride (MIA, a potent inhibitor of the sodium/proton exchange), and when the cells were treated with a membranepermeant calcium ion chelator but not when the cells were treated with an inhibitor of the sodium-dependent anion exchanger. Exposure of hepatocytes to sublytic concentrations of isopimaric and dehydroabietic acid caused a pronounced decrease in intracellular pH, by 0.8 units during exposure to 50 μM isopimaric acid and by 0.5 pH units during exposure to 50 μM dehydroabietic acid. Resin acids decreased the intracellular pH mainly by acting as proton carriers across the cell membrane, because the decrease in pH also occurred in situations in which the activity of the sodium/proton exchange was inhibited either by removing calcium from the medium or by carrying out the experiments in sodium-free medium or in medium containing MIA.
Dechlorination of chloromethanes on iron and palladium-iron bimetallic surface in aqueous systems
Authors: Wan Chuhua , Chen Yong Hong , Wei Robert
Published: March 2010

Iron granules (< 10 μ) (Fe°-H2O) and palladium-treated iron granules (Pd/Fe°-H2O) in contact with water have been tested as a potential means to dechlorinate chloromethanes (CCl4, CHCl3, and CH2Cl2) that are commonly generated in teaching chemistry laboratories. Palladium treatment enhanced the rate of dechlorination of CCl4 by a factor of about seven compared to the untreated Fe°-H2O, but the potential toxic effect of palladium remains a concern. Oxygen in the aqueous solution reduced the dechlorination rates of CCl4 with both Fe°-H2O and Pd/Fe°-H2O by at least a factor of three. Nevertheless, from the consideration of remediating solvent wastes, both systems appear suitable for treating CCl4 and possibly CHCl3 wastes, even in the presence of oxygen. The reactivities of the three chloromethanes toward the Fe°-H2O were vastly different. The dechlorination rate of CCl4 was by far the highest, followed by that of CHCl3, and CH2Cl2 was virtually unreactive toward the Fe°-H2O system. Dechlorination reactions of CCl4 and CHCl3 were systematically examined on both Fe°-H2O and Pd/Fe°-H2O. On the basis of the data, it appears that CCl4 is successively dechlorinated to form CH4 via the formation of partially dechlorinated intermediates. Proton transfer to various intermediates produces the chloromethanes: CHCl3, CH2Cl2, and CH3Cl. Furthermore, CH4 formation, independent of the proton-transferring reactions, appears to be selectively stimulated by palladium (Pd/Fe°-H2O).
Development of small outdoor microcosms for studying contaminant transformation rates and mechanisms under various water column conditions
Authors: Graham David W , Miles David , deNoyelles Frank , Smith Val H
Published: March 2010

Three outdoor microcosm treatments were developed to simulate aerobic (aerobic), thermally stratified (stratified), and anaerobic (anaerobic) water columns for assessing contaminant transformation rates under controlled, quasi-natural conditions. Twelve 3.2-m-diameter by 1.4-m-deep fiberglass tanks (11.3 m3 water volume) were used in the study, four for each treatment. The tanks were variably manipulated both physically (with internal frames and plastic layers) and chemically (with sediment trays and grass supplements) to facilitate the three environments. The manipulations successfully created three different and reproducible (both between tanks with common treatments and over time) aquatic systems for further study. The aerobic treatment produced a good simulation of a P-limited, mesotrophic water column. Alternately, both the stratified and anaerobic treatments developed eutrophic to hypereutrophic water conditions and had nutritionally balanced total nitrogen (TN) and total phosphorus (TP) levels (approximately 14:1 mg N/mg P). Mild thermal stratification was achieved in the stratified units and low-oxygen conditions were established in the anaerobic units. A trial study, using the herbicide alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], was performed to test the utility of the three microcosm designs for assessing comparative in situ contaminant transformation rates. This experiment was initiated by adding alachlor to all tanks to a final concentration of 50 μg/L. Alachlor levels and other chemical parameters were then monitored for 36 d. The estimated first-order alachlor decay coefficients and half-lives for the aerobic, stratified, and anaerobic treatments were 0.011/d (63 d), 0.024/d (29 d), and 0.020/d (35 d), respectively. Subsequent analyses showed that the highest rates of alachlor decay occurred in units with grass supplements, low DO and pH levels, and comparatively high TP levels. These results suggest that lower nutrient (i.e., low TP levels), photosynthesis-dominated aquatic systems produce lower alachlor decay rates, whereas higher nutrient, decomposition-dominated systems produce higher decay rates. This project shows that diverse physical and chemical environments can be created in small outdoor microcosms and that these systems can be used successfully to assess contaminant decay rates in natural systems.
Molt-independent growth inhibition of Daphnia magna by a vertebrate antiandrogen
Authors: Leblanc Gerald A , Mclachlan James B
Published: March 2010

The objective of this study was to identify specific physiologic parameters in crustaceans that are targeted by chemicals known to be antiandrogenic in vertebrates. We hypothesized that chemicals capable of binding to the vertebrate androgen receptor would also elicit toxicity to crustaceans by binding to specific steroid hormone receptors in an antagonistic manner. This hypothesis was tested by evaluating the effects of the antiandrogen cyproterone acetate on growth, molting, sexual differentiation, and reproduction of Daphnia magna. Exposure of daphnids to concentrations of cyproterone acetate appreciably below those that elicited mortality reduced growth but had no effect on molting. These concentrations of cyproterone acetate had no effect on various developmental and maturation parameters. Cyproterone acetate also reduced the number of offspring produced by parthenogenetically reproducing daphnids, but this effect appeared to be a consequence of the reduced size of the daphnids and their inability to accommodate a brood of more than approximately 10 eggs. These results indicate that the antiandrogen cyproterone acetate specifically targets a process critical to growth of daphnids that is independent of molting. Additional studies are warranted to established whether this is an endocrine-related toxicity to crustaceans that is associated with environmental antiandrogens such as some pesticide metabolites.
The effect of temperature on the potency of carbaryl for survival of tadpoles of the green frog (Rana clamitans)
Authors: Boone Michelle D , Bridges Christine M
Published: March 2010

This study assessed the effect of temperature on the potency of carbaryl using tadpoles of Rana clamitans. Temperature, chemical concentration, and the interaction of temperature and chemical significantly affected survival. Generally, increased temperature resulted in lower survival. This study suggests a range of temperatures realistic for a species should be used in toxicity tests.
Inventories and fluxes of polychlorinated biphenyls from a contaminated industrial site
Authors: Axelman Johan , Broman Dag
Published: March 2010

Örserum Bay is a semienclosed small bay on the Swedish east coast. A paper mill for recycled paper, situated by the bay, has released several hundred kilograms of polychlorinated biphenyls (PCBs) into the bay. A large part of the sediment was later dredged and placed in a deposit site on land. In the present investigation, the inventories of PCBs in the sediments outside the mill and various other matrices on the estate have been estimated. The release of PCBs to the surrounding environment via air, water in the bay, and groundwater was also assessed. The two major processes were volatilization from the deposit of contaminated sediments and release from bay sediments with subsequent advective water transport and volatilization. Estimates of the rate of removal in percent per year for different homolog groups clearly demonstrated that fluxes rather than concentrations should be considered in risk assessments of contaminated sites. The properties and location of the contaminated matrix governed the magnitude of the PCB leakage. In addition, the impact of physicochemical properties of the different PCB homolog groups on their environmental behavior was clear. The rate of removal from the deposit reached a maximum for tetrachlorobiphenyls (tetra-CBs), for which the rate was 0.03%/year. Measured volatilization transfer velocities in the soil at the deposit ranged from 3 × 10−11 to 1 × 10−8 cm/s. In the bay, the PCBs were much more mobile, even though there were smaller differences between the homolog groups. The dichlorobiphenyls (di-CBs) showed a rate of removal from the bay of 1.6 %/year. The rate decreased with increasing degree of chlorination up to pentachlorobiphenyls (penta-CBs). Pentachlorobiphenyls to octachlorobiphenyls (octa-CBs) were removed from the bay at a rate of 0.4 to 0.6%/year.
Mineralization of dimethylsilanediol by microorganisms isolated from soil
Authors: Sabourin Cheryl L , Carpenter John C , Leib Terry K , Spivack James L
Published: March 2010

Previous studies have shown that polydimethylsiloxane is hydrolyzed in soil to dimethylsilanediol and that dimethylsilanediol is biodegraded in soil. Previously, two soil microorganisms capable of biodegrading dimethylsilanediol were isolated and identified. In this paper, the extent of [14C]dimethylsilanediol biodegradation by these two soil microorganisms, Fusarium oxysporum Schlechtendahl and an Arthrobacter species, is investigated. The silicon-containing products of dimethylsilanediol biodegradation in liquid culture were identified by high-performance liquid chromatography coupled to argon plasma emission spectrometry (HPLC-ICP). The biodegradation of [14C]methylsilanetriol was investigated in liquid cultures and in soil by monitoring the production of 14CO2. The sorption coefficient of [14C]methylsilanetriol was determined, and the sorption coefficient of [14C]dimethylsilanediol was estimated, by measuring the amount of 14C counts in the water phase of a water-soil mixture. Methylsilanetriol was found to be mineralized in liquid cultures of F. oxysporum Schlecht. and the Arthrobacter sp. that were supplied with a primary carbon source. However, the production of 14CO2 from [14C]methylsilanetriol in soil experiments never exceeded the level of possible [14C]-containing impurities in the methylsilanetriol. Methylsilanetriol was found to be more strongly sorbed to soil, which might have reduced its bioavailability. Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer dimethylsilanediol, which is biodegraded in soil. Now mineralization of dimethylsilanediol to inorganic silicate has been demonstrated.
Effects of exposure to municipal wastewater in situ on the reproductive physiology of the fathead minnow (Pimephales promelas)
Authors: Nichols Krista M , Miles-Richardson Stephanie R , Snyder Erin M , Giesy John P
Published: March 2010

Effects of representative central Michigan wastewater treatment plant (WWTP) effluents on the reproductive physiology of fathead minnows (Pimephales promelas) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17β-estradiol (E2), and testosterone (T), and evaluating gonad histology and male secondary sex characteristics. Caged adult male and female fathead minnows were exposed for 3 weeks to WWTP effluent. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. Plasma concentrations of VTG, E2, and T in female fish, quantified by enzyme-linked immunosorbent assay (ELISA), were greater at the lacustrine site than the riverine site or WWTP sites. None of the male fish had mean plasma VTG concentrations similar to that observed in females. Most VTG concentrations in male fish were less than the VTG ELISA detection limit. Female plasma concentrations of E2 were similar among riverine and WWTP sites. Plasma concentrations of E2 in male fish were greater than the riverine site at all WWTP sites except the Williamston site, but were not significantly different from the lacustrine site. Concentrations of T in female and male fish were similar among riverine and exposure sites. No trends in hormone concentrations, male secondary sex characteristics, or gonad histology could be attributed to putative endocrine disrupter exposure in WWTP effluent. The results indicate that the risk for estrogen agonist exposure below these central Michigan WWTPs is small.
Bioaccumulation of 2,2′,5,5′-tetrachlorobiphenyl and pyrene by picoplankton (Synechococcus leopoliensis, cyanophyceae): Influence of variable humic acid concentrations and pH
Authors: Twiss Michael R , Granier Laurent , Lafrance Pierre , Campbell Peter G C
Published: March 2010

Natural dissolved organic matter (DOM) controls the aqueous phase partitioning of hydrophobic organic contaminants (HOCs), where the sum of aqueous HOCs is distributed between the bound and free forms of HOCs, that is [HOC-DOM]↔[HOC] + [DOM]. The hypothesis that the bioavailability of aqueous HOCs can be attributed solely to the concentration of the free form of HOCs was tested. Bioavailability was measured as accumulation of [14C]-PCB (IUPAC 52) and [14 C]-pyrene over 48 h by the phytoplanktonic cyanobacterium Synechococcus leopoliensis. The phytoplankton were exposed within dialysis sacs to freely dissolved HOC at concentrations that were similar in all sacs (freely dissolved PCB ∼ 125 ng/L, freely dissolved pyrene ∼55 ng/L). However, humic acid concentrations were varied among the sacs (Suwannee River humic acid [HA] = 0, 2, 5, or 20 mg/L). The experiment was designed to vary the concentrations of HOC-HA and HA while keeping the concentration of freely dissolved HOCs at the same levels in all the sacs. Sorption mechanisms were probed by manipulating the pH of the exposure medium; the hydrophobicities of the cell surface and the humic acid are pH-sensitive, whereas the freely dissolved concentration of HOCs is pH-invariant. Bioaccumulation was predominantly controlled by the freely dissolved concentration of HOC and was greater at pH 4.3 than at pH 7.3. Although sorption of the PCB-HA and pyrene-HA complexes by S. leopoliensis occurred, this mechanism did not contribute significantly to the total accumulation of PCB or pyrene. These results suggest that the accumulation of HOCs by planktonic microorganisms can be predicted on the basis of the concentration of freely dissolved HOC molecules.
Exposure of northern leopard frogs in the green bay ecosystem to polychlorinated biphenyls, polychlorinated dibenzo—p-dioxins, and polychlorinated dibenzofurans is measured by direct chemistry but not hepatic ethoxyresorufin—o-deethylase activity
Authors: Huang, Yue—Wern , Karasov, William H , Patnode, Kathleen A , Jefcoate Colin R
Published: March 2010

We measured concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in northern leopard frogs collected from the Green Bay ecosystem and explored the catalytic activity of hepatic cytochrome P450-associated monooxygenase (P450 enzyme) as a biomarker for exposure to aryl hydrocarbon receptor (AhR) agonists. The two hypotheses tested were PCH concentrations in northern leopard frogs would be positively correlated with sediment polychlorinated hydrocarbon (PCH) levels in wetland habitats along a contamination gradient and hepatic ethoxyresorufin-O-deethylase (EROD) activity of northern leopard frogs, which is presumably mediated by aryl hydrocarbon receptor (AhR), would be positively correlated with PCH concentrations in frog carcasses (whole body minus liver) from different collection sites. In 1994 to 1995, frogs from seven sites along the lower Fox River and Green Bay, USA, were assayed for hepatic EROD activities and whole carcass concentrations of PCBs, PCDDs, and PCDFs. Tissue total PCB concentrations ranging from 3 to 154 ng/g were significantly correlated with sediment PCB levels. Only one PCDD and two PCDFs at concentrations of 6 to 8 pg/g were found in the frogs collected from one of the sites. The EROD activity in frogs ranging from 186 to 270 pmol/min/mg protein was not significantly correlated with frog body weight and was similar among sites except for Peter's Marsh. No significant correlation was found between EROD activity and carcass PCB concentration. This result was consistent with the fact that the frogs collected from the Green Bay ecosystem had relatively low PCB concentrations compared with what was required for induction in the laboratory (ED50 for EROD is between 700 and 2,300 ng/g).
Effects of pond water, sediment, and sediment extracts from minnesota and vermont, USA, on early development and metamorphosis of xenopus
Authors: Fort Douglas J , Propst Timothy L , Stover Enos L , Helgen Judy C , Levey Rick B , Gallagher Kathryn , Burkhart James G
Published: March 2010

In recent studies, a high incidence of amphibian mortality and malformation has been reported in the field, suggesting that toxic and/or bioactive agents are present in the environment of the affected amphibians. This study provides evidence for this hypothesis, because it applies to several affected ponds in Minnesota and Vermont, USA. Three developmental bioassays were carried out on samples from three reference and three test sites in Minnesota and one reference and three test sites, in Vermont. The bioassays utilized Xenopus as a model system, measuring altered developmental patterns during the first 4 d of development (frog embryo teratogenesis assay-Xenopus [FETAX]), hind—limb development over a 30-d period, and tail length resorption over a 14-d period. Strong correlations were observed among the results for all three in vitro bioassays, as well as between adverse developmental effects in vitro and in the field.
Biocide testing using particles with controlled surface properties (artificial sediments)
Authors: Davies Nicola A , Edwards Paul A , Lawrence Monique AM , Simkiss Ken , Taylor Marina G
Published: March 2010

Sediments may play an important role in the accumulation of contaminants by benthic organisms. This work uses artificial particles to model natural systems and to provide a way of predicting bioavailability from sediment/contaminant interactions. The artificial particles used were a range of high performance liquid chromatography resins and a dimethylditallow ammoniumexchanged clay. The bioavailability of 2,4-dichlorophenol on these particles to the midge larva Chironomus riparius was compared with that from sand and a natural sediment. The experiments were designed so that water uptake and accumulation due to the ingestion of particles could be distinguished. The results show that very strong or very weak electrostatic interactions of the contaminant with the particles results in little accumulation of the contaminant via ingestion. When the contaminant is weakly bound to the particles by van der Waals forces, the contaminant can be released from the ingested particles. In these experiments, this occurred when the contaminant–particle interaction was hydrophobic, and it is under these conditions that 2,4-dichlorophenol was most bioavailable.
Bioaccumulation and toxicity of tributyltin to a burrowing heart urchin and an amphipod in spiked, silty marine sediments
Authors: Stronkhorst Joost , van Hattum Bert , Bowmer Tim
Published: March 2010

The presence of tributyltin (TBT) in silty sediments is regarded as a long—term threat to marine and estuarine environments due to its persistence. The bioaccumulation kinetics and toxicity of TBT in the deposit—feeding heart urchin Echinocardium cordatum was studied in silty sediment spiked with TBT and equilibrated prior to the 28-d exposure. An additional 10-d acute toxicity test was carried out with the burrowing amphipod Corophium volutator in the same sediment. Because E. cordatum has a low lipid content and apparently high elimination and metabolic rates, only a moderate degree of TBT bioaccumulation was observed, with biota—sediment accumulation factors (BASFs) of 0.09 to 0.21 (dry weight basis) and biota accumulation factors (BAFs) of 180 to 843 (wet weight basis). The lethal body residue in E. cordatum (soft tissue and skeleton) was 0.8 to 3.4 nmol TBT+/g wet weight which, considering the differences in lipid content, is comparable to data on other taxonomic groups. For E. cordatum and C. volutator, the LC50s for pore water (222 and 329 ng Sn/L) were also close to reported values for aquatic and benthic organisms. The TBT concentrations in the pore water of the silty sediment were much lower than might be expected from the octanol—water partition coefficient. The measured sediment—water partitioning coefficient Kp was 8,700 L/kg dry weight. Consequently, toxicity was observed at a relatively high TBT concentration in the bulk sediment with LC50s for E. cordatum and C. volutator of 1,594 and 2,185 ng Sn/g dry weight, respectively. The results show that TBT is highly toxic to the benthic species investigated and sorption in the silty sediment strongly reduced the bioavailability of the compound.
Comparison of the toxicity of dimethoate and cypermethrin in the laboratory and the field when applying the same bioassay
Authors: Akkerhuis Gerard A.J.M. Jagersop , Damgaard Christian , Kjær Christian , Elmegaard Niels
Published: March 2010

The present paper studies the relationship between laboratory- and field—based survival data of beetle larvae sprayed with either dimethoate or cypermethrin. The comparison for dimethoate was based on an earlier constructed pesticide—effect model derived from greenhouse data. To predict field effects, the model was supplied with field data for temperatures, the insecticide concentrations on the plants, and the control mortality rate of the beetles. The same model structure was unable to predict greenhouse mortality from cypermethrin treatment, for which reason the differences between laboratory and field for this compound are discussed on the basis of direct observations. For best comparison, the same bioassay method was used in both the greenhouse and the field in the present study. Tests were based on Gastrophysa polygoni larvae dwelling on the undersides of leaves of Fallopia convolvulus plants. Dietary uptake was regarded as the main source of exposure. The simulation results for dimethoate underestimated the field mortality even after accounting for the higher control mortality in the field in the model. It was shown that an additional increase of the toxicant—induced death rate by more than a factor of five was required for the model to fit the field data. This indicated a relatively severe impact of dimethoate under field conditions. For cypermethrin, the effects in the field increased with time, pointing at increasing exposure of and/or effects on the larvae. Contributions of the present results toward the bridging of the gap between laboratory and field are discussed.
Lead effects on the predictability of reproductive behavior in fathead minnows (Pimephales promelas): A mathematical model
Authors: Alados Concepción L , Weber Daniel N
Published: March 2010

Lead (Pb) has been shown to affect the behavior of a wide variety of vertebrates, including fish, amphibians, and mammals. This article re—examines previous data on the effect of short—term, sublethal levels of waterborne Pb on the reproductive behavior of fathead minnows (Pimephales promelas). Previous research has found that Pb decreased the time spent in displaying specific reproductive behaviors in male minnows. Because each activity performed within a sequence depends upon previous parts of the sequence, the reproductive behavior of fish is not randomly distributed but is presented as a long—range self—similar correlation. By treating these data as a fractal dimension, it is now possible to determine changes in the long—term correlation of different behavioral sequences involved in nest maintenance owing to Pb exposure (0.5 ppm Pb as Pb acetate), both before and after adult males attain reproductive maturity. We hypothesized that the scaling exponent of this fluctuation varies in relation with environmental contaminants. Known Pb—induced changes in hormonal activity may account for changes in observed reproductive and nest maintenance behaviors. Pb—exposed fish exhibited higher levels of predictability (less complexity) in their behavioral sequences, i.e., they demonstrated an increase in the scaling parameter of the fluctuation a. However, if Pb was introduced after sexual maturity was observed, there was no significant difference in the scaling component a. Thus, the use of fractal dimension may provide a useful tool to analyze the effects of environmental contaminants and other stresses.
Accumulation of polycyclic aromatic hydrocarbons in semipermeable membrane devices and caged mussels (Mytilus edulis L.) in relation to water column phase distribution
Authors: Axelman Johan , Næs Kristoffer , Näf Carina , Broman Dag
Published: March 2010

Semipermeable membrane devices (SPMDs) and blue mussels (Mytilus edulis L.) were deployed at a site contaminated by discharges of polycyclic aromatic hydrocarbons (PAHs) from an aluminium reduction plant, and at a reference site. The accumulation of PAHs in SPMDs versus mussels, along with the ability of the two matrices to predict contaminant concentrations in the ambient environment, were evaluated through concurrent measurements of particulate, dissolved, and colloidal PAHs in the water column. Analysis of the results showed that blue mussels were more efficient at sequestering PAHs than were SPMDs. The PAH profile (i.e., the relative abundance of individual PAHs) in the two matrices were similar, but differed significantly from the profile in the dissolved phase. Further, back-calculation of the ambient dissolved concentrations from SPMDs indicated systematic overtrapping with increasing hydrophobicity. Calculation of in situ bioconcentration factors (BCFs) for the blue mussels at the smelter site indicated that uptake via particles (>0.7 μm) or from colloids dominated over direct uptake from the dissolved phase, as opposed to the reference site. The in situ BCFs differed markedly from literature values, which implies that the use of mussels to predict ambient concentrations would require that site-specific BCFs be applied.
Exposure modeling of detergent surfactants—prediction of 90th-percentile concentrations in the Netherlands
Authors: Feijtel Tom C J , Struijs Jaap , Matthijs Eddy
Published: March 2010

The exposure assessment portion of an environmental risk assessment involves developing an understanding of the potential fate of materials in the environment and the use of this information to determine a predicted environmental concentration (PEC). The aquatic risk assessment for detergents in the Netherlands is based on the comparison of the 90th percentile of PECs—calculated at 1,000 m downstream the sewage outfall—to the predicted no-effect concentration (PNEC) for ecosystems or maximum permissible concentration (MPC). The 90th-percentile surfactant concentrations at 1,000 m downstream the sewage outfall can be calculated using information on release, in-sewer removal, treatment efficiency, dilution, and in-stream removal. Predicted average removals for linear alkyl benzene sulfonate (LAS), alcohol ethoxylates (AE), alcohol ethoxylated sulfates (AES), and soap were high (98–99%) and not significantly different, using the specified model input. This implies that—within the limitations of the model—only 1 to 2% of total mass entering the wastewater system will be discharged to the receiving surface waters. The monitoring data confirm the effective removal and degradation of the four major detergent surfactants during treatment in activated sludge plants and indicate that the model predictions on removal are conservative. Average measured removal ranged from 99.1% for soap to 99.8% for alcohol ethoxylates. Predicted 90th-percentile surfactant concentrations at 1,000 m downstream the sewage outfall—based on actual measured raw sewage concentrations, measured mean wastewater removal figures, and predicted in-stream removal rates—ranged from 0.5 μg/L for AE to 20 μg/L for soap.
Determination of silver speciation in wastewater and receiving waters by competitive ligand equilibration/solvent extraction
Authors: Adams Nicholas W H , Kramer James R
Published: March 2010

A competitive ligand equilibration/solvent extraction (CLE/SE) technique was used to examines silver complexation in the particulate (>0.45 μm), colloidal (<0.45 μm), and dissolved (<10 kDa) states of wastewater effluent and receiving waters. Additions of silver at near ambient levels (0.1–10 nM), followed by CLE/SE, allowed the determination of complexation sites with large stability constants (log KAgL = 11–12) responsible for silver binding. Good agreement between these constants and formation constants of well-characterized silver sulfide complexes suggests that silver in wastewater effluents and receiving waters is likely to be complexed to sulfur(—II). This is supported by previously collected data on silver and sulfide concentrations in these waters, which showed that inorganic sulfide concentrations are 200 to 300 times in excess of silver concentrations. Organic ligands appear to be insignificant in comparison to the contribution of inorganic ligands to silver binding. These inorganic ligands probably consist of metal sulfides, which are stable for hours and days in oxic waters. When complexed to these strong-affinity ligands, silver(I) is protected from photoreduction to zero-valent silver.
Acclimation-induced changes in the toxicity of zinc and cadmium to rainbow trout
Authors: Stubblefield William A , Steadman Bryan L , La Point Thomas W , Bergman Harold L
Published: March 2010

Adults and juvenile rainbow trout exposed for 21 d to sublethal levels of zinc or cadmium exhibited significant changes in their respective incipient lethal levels (ILL). Acclimation resulted in exposure-dependent changes in both tolerance (ILL concentration) and resistance (time to ILL) in both size classes of fish for each metal. The ILLs for adult rainbow trout exposed to zinc increased from 695 μg/L at 131 h for nonacclimated fish to 2,025 μ/L at 168 h for fish previously exposed to 0.5 ILL (324 μg/L zinc). The ILLs for cadmium-exposed fish increased from 6 μg/L at 187 h for nonacclimated fish to 122 μg/L at 266 h for fish acclimated to 0.5 ILL (10.2 μg/L cadmium). Similar, although somewhat less dramatic, acclimation responses were observed for juveniles with both zinc and cadmium. Juveniles were found to be approximately three times less sensitive to the toxic effects of the metals than were adult fish.
Bill malformations in double-crested cormorants with low exposure to organochlorines
Authors: Kuiken Thijs , Fox Glen A , Danesik Karen L
Published: March 2010

Eight of 20 newly hatched double-crested cormorants (Phalacrocorax auritus), captured at Doré Lake (Saskatchewan, Canada) and raised in captivity, developed malformed bills when they were 2 to 3 weeks old. Malformation was characterized by abnormal flexure and rotation of the maxilla and mandible, resulting in a crossed bill. By radiography, the premaxillary and dental bones were misshapen. Morphologically similar malformed bills in free-living cormorants have been attributed to exposure to polyhalogenated aromatic hydrocarbons. However, the concentrations of total PCBs in the livers of these captive cormorants with malformed bills and in their diet were lower than have been previously associated with such malformations and were considered too low to have been the cause. The bill malformations may have been caused by deficiency of vitamin D3, because the cormorants were kept indoors without exposure to ultraviolet light and were fed frozen fish that may have been deficient in this vitamin.
Application of whole effluent toxicity test procedures to ambient water quality assessment
Authors: de Vlaming Victor , Connor Valerie , DiGiorgio Carol , Bailey Howard C , Deanovic Linda A , Hinton David E
Published: March 2010

The U.S. Environmental Protection Agency (U.S. EPA) protocols for conducting freshwater toxicity tests have been used in California, USA, to evaluate ambient water quality since 1986. Testing evolved from conducting broad watershed surveys for assessing the distribution of toxicity to conducting detailed studies for identifying chemical causes and sources. Using Cerio-daphnia dubia tests, pulses of diazinon toxicity have been detected over a 10-year period throughout California's Central Valley in waters receiving drainage from dormant orchards. In the 1980s, toxicity to C. dubia, caused by methyl parathion and carbofuran in drainage from rice fields, was detected in the Sacramento River. Rice drainage also was toxic to two important local species, larval striped bass and Neomysis. Throughout the state, diazinon and chlorpyrifos toxicity to C. dubia occurs year-round in waters receiving drainage from urban areas. Several years of monitoring the Alamo River in Imperial County with C. dubia demonstrated a recurring seasonal toxicity pattern. Toxicity during a 3-month autumn period was caused by chlorpyrifos and diazinon and during a 2-month spring period by diazinon and carbofuran. Although most toxicity has been detected with C. dubia and linked to insecticides, other examples of toxicity have been identified. Toxicity to Selenastrum has been linked to copper and zinc from mines and to the herbicide diuron in waters receiving agricultural or urban runoff. Ammonia-caused toxicity, originating from dairies and wastewater treatment plants, to fathead minnows has also been identified. Taken together, the results reveal that the three whole effluent toxicity (WET) testing procedures, in association with toxicity identification evaluations (TIEs) and chemical analyses, can be effective for the identification of an array of toxicants originating from several land use practices. In several cases, alternative land use practices or management strategies have resulted in improved water quality as demonstrated by continued toxicity testing.
Diazinon and chlorpyrifos in urban waterways in Northern California, USA
Authors: Bailey Howard C , Deanovic Linda , Reyes Emilie , Kimball Tom , Larson Karen , Cortright Kristi , Connor Valerie , Hinton David E
Published: March 2010

Samples collected from urban streams in the cities of Sacramento and Stockton, California, USA, during the precipitation season were analyzed for diazinon and chlorpyrifos. Concentrations were determined with enzyme-linked immunosorbent assays specific for each pesticide. Two hundred thirty-one samples from the two cities were analyzed for diazinon; 85% exceeded California Department of Fish and Game water-quality criteria for this pesticide. Chlorpyrifos was measured in 90 of the samples collected from Sacramento and Stockton; 80% exceeded the California Department of Fish and Game criterion for this pesticide. Thirty-six of 47 samples (76.6%) tested for toxicity produced total mortality within 72 h with Ceriodaphnia dubia. Toxicity identification evaluations on selected samples confirmed that toxicity was primarily due to one or both of these pesticides. Uses of diazinon and chlorpyrifos in urban areas include dormant sprays on fruit trees, professional landscape and maintenance uses, and structural pest control. Pesticide concentrations were lower in a catchment favoring commercial and industrial activities compared with a catchment receiving largely residential inputs. Aerial drift from agricultural applications may play a role in storm-water concentrations.
Burrowing owls and agricultural pesticides: Evaluation of residues and risks for three populations in California, USA
Authors: Gervais Jennifer A , Rosenberg Daniel K , Fry D Michael , Trulio Lynne , Sturm Kenneth K
Published: March 2010

We examined selenium, organophosphorus, and organochlorine pesticide residues in egg, footwash, and feather samples from burrowing owls in three populations in central and southern California. Eggs from all sites contained detectable levels of p,p′-dichlorodiphenyldichloroethylene, with the San Joaquin Valley site containing up to 33 μg/g (geometric mean x¯ = 7.52). Only low levels of polychlorinated biphenyls were detected, however (geometric mean x¯ = 1.98, n = 2). Selenuim concentrations were low in all samples (geometric mean x¯ = 0.426, n = 20). Eggshells collected in 1996 were 22% thinner than eggs collected prior to 1937. In addition, feather samples contained low levels of dichlorodiphenyldichloroethylene, and footwash samples indicated exposure to the pesticide chlorpyrifos. Pesticide-use records indicated that one population might also be at risk from applications of aldicarb near nests during the breeding season.
Pollution-induced tolerance to copper of nematode communities in the severely contaminated restronguet creek and adjacent estuaries, Cornwall, United Kingdom
Authors: Millward Rod N , Grant Alastair
Published: March 2010

Pollution-induced community tolerance (PICT) has been proposed as an indicator of the deleterious effects of pollutants on communities in the field. Nematode assemblages were sampled at 10 estuarine sites that ranged from uncontaminated to grossly contaminated with metals. Relative tolerance of these assemblages to Cu was quantified using acute toxicity tests. There were large differences between sites in tolerance to Cu, and copper tolerance was strongly correlated with severity of contamination. Enhanced Cu tolerance occurred at two sites where Cu concentration in sediment was around 180 μg/g but not at a third site, where Cu concentration was 214 μg/g. This implies a threshold of effects on these nematode communities at ∼200 μg/g Cu. Comparison with studies of nematode community composition in these same estuaries indicates that PICT is at least as sensitive as the best available ecological monitoring methods. It is, however, faster to carry out and requires much less taxonomic expertise. The PICT appears to be a sensitive indicator of ecological effects of pollution and has considerable promise as a monitoring tool.
A case study of integrated risk assessment mapping in the Southland Region of New Zealand
Authors: Hutchinson Gary , McIntosh Peter
Published: March 2010

Risk assessment at the regional level requires quality resource information on critical factors for sustainable land-use decisions. This paper describes a major community initiative underway in the Southland Region of New Zealand involving geographic information systems mapping of 850,000 ha at a 1:50,000 scale. At a southerly latitude of 46° in the southern part of the South Island of New Zealand, the critical factors affecting plant growth are soil quality and air temperature. Air temperature is being measured with a network of 900 automatic data loggers positioned to represent key features of the landscape and recording maximum and minimum temperatures every hour for a full year. Data are then differentially adjusted using the nearest long-term weather station to the site to generate a 30-year normal temperature record and consequent growing-degree-day value for each site. Isocontour maps are then generated to identify microclimates of interest within the landscape. Soils of the area are being mapped at the same time and to the same scale to allow integrated development of the critical information for sustainable land-use decisions. Basic soil attributes will be interpreted to produce maps for crop suitability, vulnerability to structural degradation, and leaching risk. High-class soils will also be identified. An Internet site and a bureau service will be established. This will provide technical support and interpretation of the data for clients to encourage wide use of the information produced by the project. The project is being supported and funded by the local community in the belief that the provision of high-quality resource information will lead to significant employment opportunities in the region.