bluuebunny/crossref_metadata_2025 huggingface dataset:
Sediment quality in Los Angeles Harbor, USA: A triad assessment
Authors: Anderson, Brian S , Hunt John W , Phillips Bryn M , Fairey Russell , Roberts Cassandra A , Oakden James M , Puckett H Max , Stephenson Mark , Tjeerdema Ronald S , Long Edward R , Wilson Craig J , Lyons J Michael
Published: March 2010

Sediment quality in the Los Angeles and Long Beach Harbor area of southern California, USA, was assessed from 1992 to 1997 as part of the California State Water Resources Control Board's Bay Protection and Toxic Cleanup Program and the National Oceanic and Atmospheric Administration's National Status and Trends Program. The assessment strategy relied on application of various components of the sediment quality triad, combined with bioaccumulation measures, in a weight-of-evidence approach to sediment quality investigations. Results of bulk-phase chemical measurements, solid-phase amphipod toxicity tests, pore-water toxicity tests with invertebrate embryos, benthic community analyses (presented as a relative benthic index), and bioaccumulation measures indicated that inner harbor areas of this system are polluted by high concentrations of a mixture of sediment-associated contaminants and that this pollution is highly correlated with toxicity in laboratory experiments and degradation of benthic community structure. While 29% of sediment samples from this system were toxic to amphipods (Rhepoxynius abronius or Eohaustorius estuarius), 79% were toxic to abalone embryos (Haliotis rufescens) exposed to 100% pore-water concentrations. Statistical analyses indicated that amphipod survival in laboratory toxicity tests was significantly correlated with the number of crustacean species and the total number of species measured in the benthos at these stations. Triad measures were incorporated into a decision matrix designed to classify stations based on degree of sediment pollution, toxicity, benthic community degradation, and, where applicable, tissue concentrations in laboratory-exposed bivalves and feral fish.
Fatty acid composition of tomato leaves as biomarkers of metal-contaminated soils
Authors: Verdoni Nicole , Mench Michel , Cassagne Claude , Bessoule Jean-Jacques
Published: March 2010

The aim of this study was to determine whether fatty acid composition of leaves, cotyledons or roots could be used as an indicator of the bioavailability and of the adverse effects of heavy metals on plants. Tomato seedlings were grown on soils obtained by mixing increasing amounts of a highly metal-contaminated soil with an uncontaminated sandy soil, and the fatty acid composition of plant tissues was analyzed. The fatty acid composition of roots and cotyledons of plants grown on contaminated soils was mostly the same as in the control plants. In contrast, significant changes in the fatty acid composition of primary leaves occurred. Our results clearly indicate a relationship between metal accumulation (Cd, Pb, Zn, and Cu) and the fatty acid composition of primary leaves, with the contribution of 18 C atom fatty acids (as 18:3 fatty acid and precursors) being more closely correlated with the availability of heavy metals in soils.
Effectiveness of the sulfur(IV) compound, sodium bisulfite, in reducing chlorine, chlorine dioxide, and chlorite toxicity toDaphnia magnain well water and pond water
Authors: Yonkos Lance T , Fisher Daniel J , Burton Dennis T , Whitekettle Wilson K , Petrille Joseph C
Published: March 2010

Flow-through toxicity tests were conducted with Daphnia magna to determine the residual toxicity of chlorine, chlorine dioxide, and chlorite after treatment with the sulfur(IV) compound sodium bisulfite. Daphnids were exposed separately to 0.5-mg/L concentrations of each of the three compounds without the addition of sodium bisulfite, with a low stoichiometric dose of sodium bisulfite, and with a high stoichiometric dose of sodium bisulfite. Tests were performed in well water with a low total organic carbon (TOC) content and pond water with a high TOC content. Analysis of results indicated that sodium bisulfite did not eliminate the toxicity of chlorine dioxide or chlorite to D. magna. Total residual oxidant (TRO) concentrations were reduced and survival times were extended, but acute toxicity persisted even with a SIV concentration 10.0 times the stoichiometric ratio of oxidant. Mortality occurred in chlorine dioxide treatments in which no TRO was detected, indicating that standard analytical (amperometric) techniques may be inadequate to detect toxicity. Sodium bisulfite did succeed in eliminating chlorine toxicity except in pond water receiving a low (3.0×) sodium bisulfite dose. Oxidant reactions with organic substrates may have produced chlorinated residuals that were resistant to SIV dechlorination.
Sea urchin fertilization assay: An evaluation of assumptions related to sample salinity adjustment and use of natural and synthetic marine waters for testing
Authors: Jonczyk Emilia , Gilron Guy , Zajdlik Barry
Published: March 2010

Most industrial effluents discharged into the marine coastal environment are freshwater in nature and therefore require manipulation prior to testing with marine organisms. The sea urchin fertilization test is a common marine bioassay used for routine environmental monitoring, investigative evaluations, and/or regulatory testing of effluents and sediment pore waters. The existing Canadian and U.S. Environmental Protection Agencies test procedures using sea urchin (and sand dollar) gametes allow for sample salinity adjustment using either brine or dry salts. Moreover, these procedures also allow for the use of either natural or synthetic marine water for culturing/holding test organisms and for full-scale testing. At present, it is unclear to what extent these variables affect test results for whole effluents. The test methods simply state that there are no data available and that the use of artificial dry sea salts should be considered provisional. We conducted a series of concurrent experiments aimed at comparing the two different treatments of sample salinity adjustment and the use of natural versus synthetic seawater in order to test these assumptions and evaluate effects on the estimated end points generated by the sea urchin fertilization sublethal toxicity test. Results from these experiments indicated that there is no significant difference in test end points when dry salts or brine are used for sample salinity adjustment. Similarly, results obtained from parallel (split-sample) industrial effluent tests with natural and artificial seawater suggest that both dilution waters produce similar test results. However, data obtained from concurrent tests with the reference toxicant, copper sulfate, showed higher variability and greater sensitivity when using natural seawater as control/dilution water.
Effects of natural organic matter source on reducing metal toxicity to rainbow trout (Oncorhynchus mykiss) and on metal binding to their gills
Authors: Richards Jeff G , Curtis P Jeff , Burnison B Kent , Playle Richard C
Published: March 2010

Juvenile rainbow trout (Oncorhynchus mykiss, 3 g) were exposed for 74 h in ion-poor (soft) water to a mixed-metal solution in the presence of 4, 6, and 10 mg C/L natural organic matter (NOM). The metals were 0.2 μM Pb, 0.1 μM Hg, 0.1 μM Cd, 1.3 μM Cu, 0.05 μM Ag, and 3.5 μM Co, and the natural organic matter was isolated by reverse osmosis from three sources in southern Ontario, Canada. The six-metal solution alone was extremely toxic to the fish. Increasing concentrations of each NOM increased trout survival, but the NOM having the most allochthonous properties (from Luther Marsh) increased fish survival most, while the NOM having the most autochthonous properties (from Sanctuary Pond, Point Pelee) increased fish survival least. This pattern was reflected in the degree of reduction of Pb and Cu accumulation by the gills. Relatively simple chemical characterization of NOM, such as protein-to-carbohydrate ratios, or optical characterization, such as absorbance-to-fluorescence ratios (e.g., representing aromaticity), may adequately reflect these biologically relevant differences in organic matter quality.
Simultaneous experimental study of direct and direct plus trophic contamination of the crayfish astacus astacus by inorganic mercury and methylmercury
Authors: Simon Olivier , Boudou Alain
Published: March 2010

An experimental study was carried out to investigate direct and direct plus trophic contamination routes of the crayfish Astacus astacus by inorganic mercury (Hg(II)) or methylmercury (MeHg). Direct exposure was based on low contamination conditions, 300 and 30 ng/L in the dissolved phase, respectively, during 30 d at 20°C. Trophic exposure was based on daily consumption of the Asiatic clam Corbicula fluminea, previously contaminated during 40 d with similar exposure conditions. The Hg concentrations in the bivalves were very similar: 1,451 ± 287 ng/g for Hg(II) and 1,346 ± 143 ng/g for MeHg. In the crustaceans, Hg bioaccumulation was analyzed at the whole-organism level and in eight organs (gills, stomach, intestine, hepatopancreas, tail muscle, green gland, carapace, and hemolymph), after 15 and 30 d of exposure. Analysis of the results showed marked differences between Hg(II) and MeHg accumulation in favor of MeHg: for the direct route, the ratio between metal concentrations was close to 8; for the trophic route, no significant increase in Hg accumulation was observed for Hg(II) even when the ratio between Hg concentration in the direct plus trophic contamination route and Hg concentration in the direct contamination route was 1.6 for MeHg, with an estimated trophic transfer rate close to 20%. Mercury organotropism was also specifically connected to the exposure conditions, especially at the biological barrier level according to the route of exposure: gills and carapace for the direct route and digestive tract including hepatopancreas for the trophic route.
Comparison of laboratory and in situ sediment bioassays using Corophium volutator
Authors: Kater Belinda J , Postma Jaap F , Dubbeldam Marco , Prins Jeannot T. H J
Published: March 2010

Bioassays with the marine amphipod Corophium volutator were performed simultaneously in situ and in the laboratory using sediments sampled from the in situ locations. In most cases, the in situ response was significantly higher compared to the laboratory response. This difference was not caused by direct influence of the use of the field chamber on Corophium sp., nor was the difference caused by the overlying water used. Experiments showed homogenization can affect the toxicity of a sediment, but not in such a way that it can completely explain the difference between the response in situ and in the laboratory. Possible explanatory factors are harbor activity, storms, and temperature. To reduce the influence of some of these factors, the best period of the year to perform in situ bioassays with C. volutator is May, June, or September.
Heritability of resistance to individual contaminants and to contaminant mixtures in the sheepshead minnow (Cyprinodon variegatus)
Authors: Klerks Paul L , Moreau Casey J
Published: March 2010

Resistance heritability (the additive genetic variance out of the total phenotypic variance, signifying a population's potential to genetically adapt to detrimental levels of contamination) was quantified in the sheepshead minnow (Cyprinodon variegatus). Heritability was estimated for tolerance to individual contaminants (phenanthrene, zinc) and to contaminant mixtures (phenanthrene plus zinc, and a complex mixture with three metals and three polycyclic aromatic hydrocarbons). Estimates were obtained from resemblances between relatives, both parent–offspring pairs, and families of sibs and half-sibs. Heritabilities determined from parent–offspring regressions averaged only 0.08 (scale, 0—1), whereas resemblance among full sibs yielded heritabilities averaging 0.85. The half-sib analysis yielded heritabilities of −0.01 (sire component) and 0.77 (dam component). This pattern in the magnitude of heritabilities indicates that heritabilities for the resistance of C. variegatus to these chemicals are low (with the high resemblances among sibs being due to common environmental and dominance genetic variation rather than additive genetic variation). The parent–offspring regressions provide evidence that heritabilities may be lower if more contaminants are involved. Our results mean, then, that C. variegatus in contaminated environments is not likely to become resistant to these contaminants very rapidly, and that resistance may develop even more slowly as more contaminants become involved.
An assessment of the toxicity of phthalate esters to freshwater benthos. 2. Sediment exposures
Authors: Call Daniel J , Cox Dean A , Geiger Dianne L , Genisot Kristen I , Markee Thomas P , Brooke Larry T , Polkinghorne Christine N , VandeVenter Fred A , Gorsuch Joseph W , Robillard Kenneth A , Parkerton Thomas F , Reiley Mary C , Ankley Gerald T , Mount David R
Published: March 2010

Seven phthalate esters were evaluated for their 10-d toxicity to the freshwater invertebrates Hyalella azteca and Chironomus tentans in sediment. The esters were diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-n-hexyl phthalate (DHP), di-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and a commercial mixture of C7, C9, and C11 isophthalate esters (711P). All seven esters were tested in a sediment containing 4.80% total organic carbon (TOC), and DBP alone was tested in two additional sediments with 2.45 and 14.1% TOC. Sediment spiking concentrations for DEP and DBP were based on LC50 (lethal concentration for 50% of the population) values from water-only toxicity tests, sediment organic carbon concentration, and equilibrium partitioning (EqP) theory. The five higher molecular weight phthalate esters (DHP, DEHP, DINP, DIDP, 711P), two of which were tested and found to be nontoxic in water-only tests (i.e., DHP and DEHP), were tested at single concentrations between 2,100 and 3,200 mg/kg dry weight. Preliminary spiking studies were performed to assess phthalate ester stability under test conditions. The five higher molecular weight phthalate esters in sediment had no effect on survival or growth of either C. tentans or H. azteca, consistent with predictions based on water-only tests and EqP theory. The 10-d LC50 values for DBP and H. azteca were >17,400, >29,500, and >71,900 mg/kg dry weight for the low, medium, and high TOC sediments, respectively. These values are more than 30× greater than predicted by EqP theory and may reflect the fact that H. azteca is an epibenthic species and not an obligative burrower. The 10-d LC50 values for DBP and C. tentans were 826, 1,664, and 4,730 mg/kg dry weight for the low, medium, and high TOC sediments, respectively. These values are within a factor of two of the values predicted by EqP theory. Pore-water 10-d LC50 values for DBP (dissolved fraction) and C. tentans in the three sediments were 0.65, 0.89, and 0.66 of the water-only LC50 value of 2.64 mg/L, thereby agreeing with EqP theory predictions to within a factor of 1.5. The LC50 value for DEP and C. tentans was >3,100 mg/kg dry weight, which is approximately 10× that predicted by EqP theory. It is postulated that test chemical loss and reduced organism exposure to pore water may have accounted for the observed discrepancies with EqP calculations for DEP.
Distribution, speciation, and bioavailability of lanthanides in the Rhine-Meuse estuary, The Netherlands
Authors: Moermond Caroline T A , Tijink Jakolien , van Wezel Annemarie P , Koelmans Albert A
Published: March 2010

Changing environmental conditions may influence the fate and bioavailability of lanthanides (part of the rare earth elements [Ln]) in estuaries. The aim of this study was to quantify the variation in estuarine lanthanide solid/water distribution, speciation, and bioaccumulation. The latter was studied in the amphipod Corophium volutator under field and laboratory conditions. Calculations with the chemical equilibrium model MINEQL+ indicate that dissolved lanthanides are complexed mainly to carbonates and dissolved organic matter. In the water phase, the relative abundance of the free ion, LnCO3, and humic complexes decreases from lanthanum to lutetium, whereas the relative abundance of Ln(CO3)2 increases. Cerium and europium anomalies were found in the water. Europium anomalies were also found in some biota. The biota sediment accumulation factors (BSAFs) decreased across the series from lanthanum to lutetium. Regression analysis revealed that alkalinity correlated negatively with lanthanide uptake. This suggests that increasing complexation reduced bioavailability under the prevailing conditions. The BSAFs did not depend on salinity or pH, which may simplify sediment-quality criteria for fresh versus saline waters. Field BSAFs were significantly lower than laboratory values for the same sediments, which is explained by adaptation of the organisms to lanthanides.
Experimental exposure of naive bank voles (Clethrionomys glareolus) to the Chornobyl, Ukraine, environment: A test of radioresistance
Authors: Rodgers Brenda E , Wickliffe Jeffrey K , Phillips Carleton J , Chesser Ronald K , Baker Robert J
Published: March 2010

Previous studies have demonstrated no difference in micronucleus (MN) frequencies between wild rodents chronically exposed to the environmental radiation contamination of the Chornobyl (Ukraine) exclusion zone and those inhabiting reference populations. The aim of the present study was to test the hypothesis that a population of bank voles (Clethrionomys glareolus) has developed radioresistance as a result of 14 years of chronic, low-dose radiation exposure. Naive voles were placed in environmental enclosures in the Red Forest region of the exclusion zone for 30 d. Blood samples were obtained at regular intervals, and the MN assay was used to assess chromosomal damage. Additionally, radionuclide uptake was monitored throughout the study, and dose was documented for each individual as well as for their offspring. Total dose for the voles experimentally exposed in this environment averaged 1.09 Gy (36.20 mGy d−1) for the 30-d study period. Our results indicate that exposure to radiation levels well above regulatory statutes did not result in an increased MN frequency. Furthermore, our results do not support the hypothesis that voles chronically exposed to these radiation levels have developed a genetic basis for radioresistance that is unique from that present in naive populations. The use of C. glareolus as a sentinel species for environmental studies of radiation contamination and the question of whether the MN assay is an appropriate endpoint for studies of low-dose, chronic radiation exposure are also discussed.
How water oxygenation level influences cadmium accumulation pattern in the Asiatic clam Corbicula fluminea: A laboratory and field study
Authors: Tran Damien , Boudou Alain , Massabuau Jean-Charles
Published: March 2010

The level of O2 in water is highly variable in the aquatic environment and is a major ventilatory drive in all animals breathing water. Low O2 partial pressure (Po2) strongly stimulates ventilatory activity compared to air-equilibrated or O2-enriched water. We studied the influence of ventilatory activity on the bioaccumulation rate of Cd in the freshwater Asiatic clam Corbicula fluminea for Po2 ranging from 4 to 40 kPa (2–20 mg/L at 15°C) during steady-state exposure to controlled concentrations of Cd of approximately 2 or 0.5 μg/L under both laboratory and field conditions. The concentration of Cd in the expired water and its apparent extraction coefficient (Ewcd) from the ventilated water were calculated. Results show that a low Po2 strongly enhanced Cd bioaccumulation rate in the whole soft body and modified the distribution pattern and the relative burden in the organs. Whatever the water Po2, values for the concentration of Cd in the expired water remained close to the Cd concentration in the inspired water and Ewcd varied from 2 to 12%. Because the field results conformed to the laboratory analysis, the suggestion is made that the influence of O2 on bioaccumulation patterns of metals in water-breathers should be classified as of primary importance.
An interlaboratory study on the use of steroid hormones in examining endocrine disruption
Authors: McMaster Mark E , Jardine Janet J , Ankley Gerald T , Benson William H , Greeley Mark S , Gross Timothy S , Guillette Louis J , MacLatchy Deborah L , Orlando Edward F , Van Der Kraak Glen J , Munkittrick Kelly R
Published: March 2010

In recent years, there has been an increased use of the measurement of sex steroid hormone levels in the blood of animals exposed to chemicals as an indicator of reproductive impairment or an alteration in endocrine function. Although levels of hormones are often compared among animals and laboratories, there has been no study to examine the between-laboratory variability in actual steroid measurements. Therefore, we initiated a study with white sucker collected from a site receiving pulp mill effluent, previously documented as having reduced steroid levels, to address this issue. Samples of plasma and media from in vitro gonadal incubations were delivered to eight outside laboratories with the ability to measure steroid hormones. These laboratories ranged from well-established fish endocrine laboratories to wildlife toxicology laboratories, which have recently implemented the methods to measure steroid hormones. In this study, we have considered both the absolute measure of steroid content between laboratories as well as the ability to discriminate between reference and exposed populations as important criteria when evaluating the utility of these measures. Of the eight outside laboratories conducting the analyses, six detected identical site differences in circulating levels of testosterone and 17β-estradiol to those documented by our Burlington laboratory (ON, Canada). However, the absolute value of the steroid hormones measured in the plasma varied significantly (plasma testosterone 0.6–23.1 ng/ml, 17β-estradiol 77.6–1782.7 pg/ml) with coefficients of variation of 70.4% and 60.3% respectively. Similar results were demonstrated for the measurement of steroid hormones in media following in vitro gonadal incubation. Although there was a fair amount of variability in the absolute measure of steroid hormone levels, we would predict a far greater coherence of interlaboratory results through the sharing of reagents and the use of a common methodology between laboratories. These results are very promising, providing evidence for the inclusion of steroid hormones in monitoring endocrine disruption in wildlife species.
Naturalized salmonid populations occur in the presence of elevated trace element concentrations and temperatures in the firehole river, Yellowstone National Park, Wyoming, USA
Authors: Goldstein Jack N , Hubert Wayne A , Woodward Daniel F , Farag Aïda M , Meyer Joseph S
Published: March 2010

We investigated the effects of geothermally influenced waters on the distribution of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta, in the Firehole River and its tributaries in Yellowstone National Park (WY, USA) from June 1997 to June 1998. Geothermal features in the Firehole River basin elevate mineral content and temperature in portions of the river and its tributaries. We found concentrations of boron and arsenic to be elevated in geothermally influenced areas compared with upstream sites. Boron concentrations occasionally exceeded 1,000 μg/L, a proposed limit for the protection of aquatic organisms. Arsenic concentrations occasionally exceeded 190 μg/L, the chronic ambient water quality criterion. Temperatures in geothermally influenced sites ranged up to 30°C and were consistently 5 to 10°C higher than upstream sites unaffected by geothermal inputs. Rainbow trout occurred at sites with elevated concentrations of boron, arsenic, and other trace elements and elevated water temperatures. Rainbow trout inhabited and spawned at sites with the most elevated trace element concentrations and temperatures; however, brown trout were absent from these sites. Water temperature may be the major factor determining brown trout distributions, but we cannot exclude the possibility that brown trout are more sensitive than rainbow trout to boron, arsenic, or other trace elements. Further investigations are needed to determine species-specific tolerances of boron, arsenic, and other trace elements among salmonids.
Altered distribution of lipid-soluble antioxidant vitamins in juvenile sturgeon exposed to waterborne ethynylestradiol
Authors: Palace Vincr P. , Evans Robert E , Wautier Kerry , Baron Christopher L , Werner Julieta , Klaverkamp Jack F , Kidd Karen A , Dick Terry A
Published: March 2010

Studies in mammals have shown that exposure to estrogenic compounds can affect lipid metabolism and plasma concentrations of lipid-soluble vitamins. However, the potential for estrogenic contaminants to induce these effects in fish has not yet been examined. The ability of the estrogen analog ethynylestradiol (EE2) to alter concentrations of the lipid-soluble vitamins A and E in plasma, liver, and kidney was investigated in juvenile lake sturgeon (430 ± 20 g). The EE2 was delivered to the sturgeon in the tank water at nominal concentrations of 0 (control), 15, 60, or 125 ng EE2/L for a period of 25 d. Concentrations of the egg yolk precursor, vitellogenin, increased dose dependently in plasma. Plasma vitamin E (tocopherol), A1 (retinol), and A2 (dehydroretinol) were elevated by the two highest EE2 treatments compared with the controls. Esterified storage forms of vitamin A were marginally lower in the livers of fish from the highest EE2 dose group, but vitamin E levels in the liver were not significantly affected. Concentrations of vitamin E and vitamin A were significantly depleted in the kidney of fish from the two highest EE2 dose groups. Total lipid content was elevated in the gonad of fish treated with the highest dose of EE2 compared with the controls. Altered lipid and vitamin distribution may be induced by estrogen to facilitate gonadal maturation in sturgeon. Results from these studies indicate that an examination of the implications for vitamin depletion by estrogenic contaminants in juvenile fish is warranted.
Testing of metal bioaccumulation models with measured body burdens in mice
Authors: Torres Kevin C , Johnson Michael L
Published: March 2010

Estimates of chemical accumulation in prey organisms can contribute considerable uncertainty to predictive ecological risk assessments. Comparing body burdens calculated in food web models with measured tissue concentrations provides essential information about the expected accuracy of risk indices. Estimates of arsenic, cadmium, copper, lead, and nickel body burdens in house mice (Mus musculus) inhabiting a seasonal wetland were generated with two small mammal bioaccumulation models. Published soil-to-small mammal bioaccumulation regression models produced accurate estimates of arsenic and lead body burdens but failed to adequately predict copper and nickel levels in mice. Incorporating conservative prediction intervals in the regression models shows potential for successful applications in screening-level risk assessments. A simple mechanistic cumulative ingestion bioaccumulation model overpredicted lead levels in mice generally by less than one order of magnitude but greatly overpredicted concentrations of arsenic, copper, and nickel. Better estimates of absorption and elimination of ingested metals and knowledge of specific arthropod taxa in house mouse diets are likely to improve the accuracy of the cumulative ingestion model. Applying Monte Carlo simulations to the soil–small mammal regression models generated probabilistic estimates of body burdens that were consistent with deterministic results. However, deterministic minimum and maximum predictions of the ingestion model were excessively conservative (widely spaced) relative to lower and upper probabilistic percentiles. Metal levels predicted in individual mice on the basis of mouse-specific parameter values and exposures were not significantly more accurate than bioaccumulation predictions for the sitewide population.
Toxicity of cadmium to Caenorhabditis elegans (Nematoda) in whole sediment and pore water—the ambiguous role of organic matter
Authors: Höss Sebastian , Henschel Thomas , Haitzer Markus , Traunspurger Walter , Steinberg Christian E W
Published: March 2010

A bioassay using the nematode Caenorhabditis elegans was performed with natural sediment that had been spiked with organic matter (36–117 g total organic carbon/kg dry wt) and cadmium (Cd; 10–1,200 mg/kg wet wt). Whole sediment and pore water were tested to study the influence of particulate organic matter (POM) and dissolved organic matter (DOM) on Cd toxicity and to compare the toxicity of the two sediment phases. Toxicity was measured with nematode growth as test parameter. No toxicity was observed if sediment concentrations of Cd were below concentrations of acid-volatile sulfides (AVS). At higher Cd concentrations, toxicity in whole sediment and pore water increased with increasing organic content. This phenomenon was explained by an increase of DOM concentrations in organically enriched treatments and a resulting solubilization of Cd due to Cd complexation by DOM. Because DOM did not alter the bioavailability of Cd for the nematodes, bacteria, serving as food, might have functioned as vectors for Cd-DOM complexes, so that Cd could have become available in the gut of the nematodes. A higher toxicity in whole sediment compared to in pore water in the organically enriched treatments indicated that POM-bound Cd may have contributed to the toxicity of Cd to C. elegans.
Lead poisoning in the globally threatened marbled teal and white-headed duck in Spain
Authors: Mateo Rafael , Green Andy J , Jeske Clinton W , Urios Vicente , Gerique Cati
Published: March 2010

Marbled teal (Marmaronetta angustirostris) and white-headed duck (Oxyura leucocephala) are the two European ducks threatened with global extinction. We investigated lead (Pb) poisoning in stifftails (Oxyura spp., n = 83) and marbled teal (n = 80) shot or found dead or moribund in Spanish wetlands via gizzard examination and liver, bone, and blood Pb analysis. Ingested Pb shot was present in 32% of shot stifftails and 70 and 43% of dead or moribund stifftails and marbled teal, respectively. Lead-shot ingestion was more frequent in Valencia (eastern Spain), where Pb-shot densities were higher and grit scarcer. Selection of larger grit similar in size to Pb shot may explain the higher rate of Pb-shot ingestion observed in stifftails. Ingested shot was found more frequently in juvenile stifftails than in adults. Lead bone concentrations were higher in ducklings <9 d old than in fully grown teal and were also higher in adult than in juvenile teal. Our results show the need for a ban of Pb shot for waterfowl hunting in Spain and the cleanup of spent shot at major wetlands.
Persistence and retention of active ingredients in four granular cholinesterase-inhibiting insecticides in agricultural soils of the lower Fraser River valley, British Columbia, Canada, with implications for wildlife poisoning
Authors: Wilson Laurie K. , Elliott John E. , Vernon Robert S. , Smith Barry D. , Szeto Sunny Y.
Published: March 2010

The persistence and retention of active ingredients in granules of Thimet 15G (phorate 15% by weight), Dyfonate 10G (fonofos 10% by weight), Counter 15G (terbufos 15% by weight), and Furadan 10G (carbofuran 10% by weight) were determined in silt loam and organic muck agricultural soils typical of the lower Fraser River valley (BC, Canada). In June 1995, treatment bags made of polyester cloth (7.5 × 7.5 cm) containing granules of a single insecticide, either alone or with soil, were placed during spring planting in the bottom of the furrow and retrieved periodically until April 1996. The parent component of each insecticide declined monotonically except for carbofuran (logistic decline). In the silt loam (organic muck) soil, the average June-to-October first-order rate constants and half-lives were 0.009 (0.010)/d and 80 (71) d for fonofos, 0.012 (0.009)/d and 58 (82) d for phorate, and 0.032 (0.015)/d and 21 (47) d for terbufos; the half-life of carbofuran was 129 (97) d. By December, the average amounts of fonofos and phorate in silt loam (organic muck) were 26% (range: 17–40%; 14% [range: 3.4–21%]) and 21% (range: 15–30%; 10% [range: 5.0–24%]) of the initial amounts of active ingredients measured at time zero, respectively. By April, the percentages dropped to 16% (range: 7.8–24%; 2.3% [range: 0–7.7%]) and 7.3% (range: 1.9–25%; 0.6% [range: 0–1.9%]). During this period, about 95% of the active ingredients were granule bound, the rest remaining in the bag. Only low levels of terbufos and carbofuran persisted in both soils from December to April of the following year. Results indicate an enhanced probability for poisoning of waterfowl and raptors because of the high levels of active ingredients retained on granules of all four insecticides in both soils in the fall. The risk of acute poisoning by phorate and fonofos continued though the winter.
Developmental disorders in embryos of the frog Xenopus laevis induced by chloroacetanilide herbicides and their degradation products
Authors: Osano Odipo , Admiraal Wim , Otieno Dismas
Published: March 2010

Pesticides are known to transform in the environment, but so far the study of their effects in the environment has concentrated on the parent compounds, thereby neglecting the effects of the degradation products. The embryotoxic, developmental, and teratogenic effects of chloroacetanilide herbicides and their environmentally stable aniline degradation products were investigated in this study in view of the massive application of alachlor and metolachlor. Embryos at midblastula to early gastrula stages of a locally abundant African clawed frog Xenopus laevis were used as test organisms. The embryos were exposed to the test chemicals for 96 h in each experiment. Alachlor is more embryotoxic (the concentration causing 50% embryo lethality, 96-h LC50 = 23 μM [6.1 mg/L]) and teratogenic (teratogenic index [TI] = 1.7) than metolachlor (96-h LC50 5 48 μM [13.6 mg/L], TI = 0.2). The degradation products of alachlor and metolachlor, respectively, 2,6-diethylaniline (96-h LC50 = 13 μM [19.4 mg/L], TI = 2.1) and 2-ethyl-6-methyaniline (96-h LC50 = 509 μM [68.8 mg/L], TI 5 2.7), are less embryotoxic but more teratogenic than their parent compounds. The most common teratogenic effects observed were edema for alachlor as opposed to axial flexures and eye abnormalities for 2,6-diethylaniline and 2-ethyl-6-methylaniline. Metolachlor is found to be an example of a nonteratogenic herbicide that upon degradation loses toxicity but gains teratogenicity, and both the herbicides, metolachlor and alachlor, are potential sources of teratogenic transformation products.
Combined effects of lowered oxygen and toxicants (copper and diazinon) on the mayfly Ephoron virgo
Authors: Van Der Geest Harm G. , Soppe Walter J. , Greve Gerdit D. , Krono Alice , Kraak Michiel H. S.
Published: March 2010

In many large European rivers, the number of typical riverine insect species, such as mayflies, stoneflies, and caddisflies, is greatly reduced compared to historic records. This can no longer be explained by high concentrations of a relatively small number of dominant toxicants since many rivers have changed from heavily contaminated systems with a few selected key toxicants to systems with a complex contamination. This contamination consists of many substances in low concentrations coinciding with other unfavorable conditions, such as low oxygen concentrations. It was hypothesized that the joint adverse effects of such multiple stressors may be a steering factor in the distribution of riverine insect species. The aim of this study was therefore to determine the combined effects of toxicants and oxygen depletion. To this purpose, larvae of the indigenous riverine mayfly Ephoron virgo were exposed to two different model toxicants, copper and diazinon, under normoxia and hypoxia (50% air saturation) conditions. The median effective concentrations for mortality for copper were significantly lower in the hypoxia treatments than in the normoxia treatments. For diazinon, no differences were observed between two treatments differing in dissolved oxygen levels, and therefore we argue that interactions between multiple stressors may be compound specific. It is concluded that the combination of toxicants and lowered oxygen may have a stronger impact than can be expected based on the adverse effects of the individual factors and that standard toxicity tests may be insufficient alone to determine the impact of human activities on the ecological state of riverine communities. Instead, attention needs to be paid to more environmentally realistic nonoptimal conditions in toxicity testing to adequately fulfill the needs of ecological recovery programs.
A cautionary note on the use of species presence and absence data in deriving sediment criteria
Authors: Von Stackelberg Katherine , Menzie Charles A.
Published: March 2010

In recent years, a variety of approaches to deriving sediment quality guidelines have been developed. One approach relies on establishing an empirical relationship between the concentration of a contaminant in sediment and the condition of some biological indicator, for example, combining measured sediment concentrations of contaminants combined with data on colocated benthic species to measure in situ community effects of contamination. Biological threshold concentrations derived in this manner are being considered or have already been adopted by some regulatory agencies as a means for deriving sediment guidelines (e.g., Canada's Provincial Sediment Quality Guidelines). In order to test the validity of this method, we constructed several Monte Carlo simulations to illustrate that the methodology used to develop these guidelines is flawed by the effects of sampling and statistical artifacts that emerge from undersampling a lognormal density function. As a case study, this paper will present the screening level concentration method used by the Ontario Ministry of the Environment (Toronto, ON, Canada) and provide the results of several probabilistic exercises highlighting these issues. We present a word of caution on the applicability of methods that rely exclusively on statistical and mathematical relationships between invertebrate data and sediment concentrations to derive sediment quality guidelines.
Response of the amphibian tadpole (Xenopus laevis) to atrazine during sexual differentiation of the testis
Authors: Tavera-Mendoza Luz , Ruby Sylvia , Brousseau Pauline , Fournier Michel , Cyr Daniel , Marcogliese David
Published: March 2010

Xenopus laevis tadpoles were exposed for 48 h during sexual differentiation to atrazine at 21 μg/L under static laboratory conditions at 21 ± 0.5°C. After this exposure period, tadpoles were fixed and the kidney-gonad complex was microdissected. Quantitative histological analysis of the gonad revealed a 57% reduction in testicular volume among atrazine-exposed tadpoles. In addition, primary spermatogonial cell nests that represent germ cells for the life of the organism were reduced by 70%. Nursing cells, which provide nutritive support for the developing germ cells, had declined by 74%. Testicular resorption was observed among 70% and aplasia or failure of full development of the testis was recorded in 10% of the atrazine-exposed tadpoles. Because cell nests represent the pool of primordial germ cells for the reproductive life of the organism, the combined reduction in spermatogonial cell nests and nursing cells suggest that a pulse exposure to 21 μg/L of atrazine during sexual differentiation could significantly reduce reproduction during the reproductive life of these animals.
Responses of biofilms to combined nutrient and metal exposure
Authors: Ivorra Núria , Hettelaar Jenny , Kraak Michiel H. S. , Sabater Sergi , Admiraal Wim
Published: March 2010

Numerous studies have reported marked sensitivities of diatom species to phosphate and organic pollution but have ignored interactions with other common contaminants. The aim of the present study was to investigate the single and joint effects of increased phosphate and metal (cadmium, zinc) concentrations on benthic diatom communities. Microalgal biofilms from a relatively unpolluted stream were exposed in the laboratory to Zn, Cd, and P, separately and in combination, in concentrations found at a polluted stream in the same catchment. The Zn concentration reduced algal growth in biofilms more than the Cd concentration. Phosphate compensated for the single effect of each metal but not for their combined effects. Diatom community changes were evaluated using water quality indices based on the empirical sensitivities of taxa to nutrients (TDI) and organic pollution (%PTV). Phosphate exposure resulted in an increase of the eutrophy rank and presumed pollution-tolerant taxa. In contrast, exposure to Zn, Zn + Cd, and Zn + Cd + P caused a marked reduction of the TDI and %PTV community values. The successional trends in the laboratory matched the observed differences in microphyte communities in the reference and polluted river stations. However, the autoecology of the species present also revealed that the resulting composition of diatom communities cannot be attributed solely to the direct toxic effects of metal and nutrients and their interaction. Observed changes in the relative abundance of species are also determined by their growth form and microdistribution in biofilms.
Copper toxicity to larvalMercenaria mercenaria(hard clam)
Authors: LaBreche Timothy M. C. , Dietrich Andrea M. , Gallagher Daniel L. , Shepherd Natalie
Published: March 2010

Preset larval Mercenaria mercenaria were exposed to nominal concentrations of 1 (control) to 495 μg Cu/L in artificial seawater and monitored for mortality, activity, development, and metamorphosis in sealed 30-mm plastic petri plates containing 1.5 ml of artificial seawater or toxicant solution. The plastic petri plates sorbed only about 2.6 μg/L at any dose and allowed direct observation of larval clams under a light microscope for a period of two weeks; control survivorship was in excess of 60% at 400 h. The dose-response curve for mortality for clams exposed to copper and fed Isochrysis galbana was characterized by survival similar to or better than controls at doses of 5 and 14 μg Cu/L, while doses of 7 and ≥29 μg Cu/L exhibited mortality greater than controls. Values of lowest concentration at which 50% of the organisms died (LC50) were 62.4, 21.2, and 11.7 μg Cu/L, and the lowest observed adverse effect concentration values of 57, 29, and 29 μg Cu/L were determined at 48, 96, and 192 h, respectively. In contrast, activity, as judged by swimming, exhibited a typical exponentially decreasing response at these same concentrations. Experiments on the uptake of dissolved copper by I. galbana confirmed literature reports that these algae concentrate copper. Ingesting copper-containing algae was demonstrated to be a source of copper toxicity for larval clams.
Xenoestrogenic gene exression: Structural features of active polycyclic aromatic hydrocarbons
Authors: Schultz T. Wayne , Sinks Glendon D.
Published: March 2010

Estrogenicity was assessed using the Saccharomyces cerevisiae-based Lac-Z reporter assay and was reported as the logarithm of the inverse of the 50% molar β-galactosidase activity (log[EC50−1]). In an effort to quantify the relationship between molecular structure of polycyclic aromatic hydrocarbons (PAHs) and estrogenic gene expression, a series of PAHs were evaluated. With noted exceptions, the results of these studies indicate that the initial two-dimensional structural warning for estrogenicity, the superpositioning of a hydroxylated aromatic system on the phenolic A-ring of 17-β-estradiol, can be extended to the PAHs. This two-dimensional-alignment criterion correctly identified estrogenicity of 22 of the 29 PAHs evaluated. Moreover, the estrogenic potency of these compounds was directly related to the size of the hydrophobic backbone. The seven compounds classified incorrectly by this structural feature were either dihydroxylated naphthalenes or aromatic nitrogen-heterocyclic compounds; all such compounds were false positives. Results with dihydroxylated naphthalenes reveal derivatives that were nonestrogenic when superimposed on the phenolic A-ring of 17-β-estradiol had the second hydroxyl group in the position of the C-ring or were catechol-like in structure. Structural alerts for nitrogen-heterocyclic compounds must take into account the position of the hydroxyl group and the in-ring nitrogen atom; compounds with the hydroxyl group and nitrogen atom involved with the same ring were observed to be nonactive.
Methods for toxicity assessment of contaminated soil by oral or dermal uptake in land snails: Metal bioavailability and bioaccumulation
Authors: Vaufleury Annette Gomot-de , Pihan François
Published: March 2010

Using two biological characteristics of the land snail (subspecies Helix aspersa aspersa and Helix aspersa maxima), i.e., soil eating and crawling on wet surfaces, methods were developed to assess the bioavailability of heavy metals (Cd, Cr, Pb, and Zn) from soil and aqueous leachates of soil. Measurement of heavy-metal concentrations in soil, leachates, and soft tissues of snails showed that contamination from ingested soil is the major route for metal uptake. Generally, the concentrations of metals were greater in the viscera than in the foot and rose with the proportion of spiked soil (S1) in the diet. After ingestion of soil, bioaccumulation factors in the viscera were over two for Cd (3.5–27) and Zn (1.7–4.4) for both subspecies but were below one for Cr(0.04–0.6, exceptfor H. aspersa maxima: 1.21) and Pb(0.02–0.23). Contamination by leachate S1 mainly caused accumulation of Cr in the tissues. Determining the metal burden per snail enables an estimation to be made of the risk of secondary poisoning encountered by predators. The present study provides data on the bioavailability of metals in soils and on the relationships between bioaccumulation and sublethal effects.
A logical starting point for developing priorities for lizard and snake ecotoxicology: A review of available data
Authors: Campbell Kym Rouse , Campbell Todd S.
Published: March 2010

Reptiles, specifically lizards and snakes, usually are excluded from environmental contamination studies and ecological risk assessments. This brief summary of available lizard and snake environmental contaminant data is presented to assist in the development of priorities for lizard and snake ecotoxicology. Most contaminant studies were not conducted recently, list animals found dead or dying after pesticide application, report residue concentrations after pesticide exposure, compare contaminant concentrations in animals from different areas, compare residue concentrations found in different tissues and organs, or compare changes in concentrations over time. The biological significance of the contaminant concentrations is rarely studied. A few recent studies, especially those conducted on modern pesticides, link the contaminant effects with exposure concentrations. Nondestructive sampling techniques for determining organic and inorganic contaminant concentrations in lizards and snakes recently have been developed. Studies that relate exposure, concentration, and effects of all types of environmental contaminants on lizards and snakes are needed. Because most lizards eat insects, studies on the exposure, effects, and accumulation of insecticides in lizards, and their predators, should be a top priority. Because all snakes are upper-trophic-level carnivores, studies on the accumulation and effects of contaminants that are known to bioaccumulate or biomagnify up the food chain should be the top priority.