bluuebunny/crossref_metadata_2025 huggingface dataset:
Aluminum bioconcentration at the gill surface of juvenile Atlantic salmon in acidic media
Authors: Wilkinson Kevin J. , Campbell Peter G. C.
Published: March 2010

Aluminum uptake by Atlantic salmon was examined in the laboratory at pH 4.5, under conditions similar to those found in running waters on the Canadian Precambrian Shield during spring snowmelt. Gill uptake of Al was slow, approaching steady state only after 3 d of exposure. The greatest fraction of gill-associated Al was sorbed not to the gill surface itself, but to the gill mucus. Mucus appears to retard Al transport from solution to the membrane surface, thus delaying the acute biological response of the fish. Strongly associated gill [Al] was never greater than 10% of total gill Al in the early stages (<3 d) of the experiment; however, longer experiments (7 d) indicated that this Al fraction could eventually exceed 50% of the total gill Al. In contrast to uptake, depuration of Al was extremely rapid; total gill [Al] of fish exposed to Al (pH 4.5) for 2 d decreased by 60% after only 2 h in an Al-free medium (t1/2 = 0.9 h). The effect of fluoride complexation on Al bio-concentration was also examined. For equivalent Al3+ concentrations, sorption of Al to the gill surface was higher in the presence of fluoride than in its absence, which suggests the formation of mixed ligand [F-Al-L-gill] complexes at the gill surface.
Pesticide inputs and risks in coastal wetlands
Authors: Clark James R. , Lewis Michael A. , Pait Anthony S.
Published: March 2010

Coastal wetland habitats may receive pesticide inputs indirectly from agricultural and forest control of weeds and insects in upland drainage areas; indirectly or directly from weed, insect, and biofouling control from development of adjacent lands for agricultural, recreational, or residential uses; and directly from control activities practiced within wetlands for protection of public health or for nuisance abatement. Persistent and bioaccumulative pesticides used at upland sites have threatened coastal wetland biota. For more biodegradable contemporary pesticides, concerns for ecological impact are more a function of the proximity of the site of application relative to the wetland, and time available for degradation and sorption. In addition, the rate and extent of localized mixing, flushing, and stratification within the wetland can greatly affect exposure concentrations and durations for wetland biota. The short-term, direct toxic effects of pesticides on aquatic biota inhabiting coastal wetlands have been characterized in laboratory and field studies; however, assessment of the cumulative and indirect effects of repeated exposures to multiple chemicals at sublethal concentrations is a major research need.
Inhibition of glucosephosphate isomerase allozymes of the mosquitofish, Gambusia holbrooki, by Mercury
Authors: Kramer Vincent J. , Newman Michael C.
Published: March 2010

Frequencies of allozyme genotypes are being used as population-level indicators of environmental heavy-metal contamination. A genotype of glucose phosphate isomerase, Gpi-238/38, of mosquitofish (Gambusia holbrooki) has been identified as “mercury-sensitive” in an acute toxicity assay. Partially purified preparations of GPI-2 38/38 and GPI-2 100/100 were assayed to determine differences in maximum gluconeogenic reaction velocity at seven mercury (added as HgCl2) concentrations, 15 to 960 nM Hg. Log-Probit analysis of the inhibition curves indicated that the log(IC50) (log10 of the Hg concentration causing a 50% reduction in reaction velocity) for GPI-2 100/100 was significantly lower than that for GPI-2 38/38, even though GPI-2 100/100 initial uninhibited reaction velocity was greater than that of GPI-2 38/38. Although the mechanism of inhibition was not experimentally determined, under the assumption of noncompetitive interaction between Hg and GPI-2, the inhibitor dissociation constants (95% asymptotic C.I.) for GPI-2 100/100 and GPI-2 38/38 were estimated from the log (IC50) as 204 nM Hg (155-269 nM Hg) and 479 nM Hg (363-617 nM Hg), respectively. These results suggested that Hg susceptibility related to the Gpi-238/38 genotype in acute toxicity assays was likely not due to enhanced Hg inhibition of GPI-2 38/38.
Chemical fate and transport in a domestic septic system: Biodegradation of linear alkylbenzene sulfonate (LAS) and nitrilotriacetic acid (NTA)
Authors: Shimp R.J. , Lapsins E.V. , Ventullo R.M.
Published: March 2010

The biodegradation of linear alkylbenzene sulfonate (LAS) and nitrilotriacetic acid (NTA) was assessed in an established septic tank system and an adjoining shallow sand aquifer (located near Cambridge, Ontario). Studies were conducted on soil, aquifer sediment, and groundwater samples from a transect of the septic tank effluent plume. LAS and NTA were readily biodegraded in the vicinity of the discharge, with mineralization half-lives in soil and sediment samples collected near the tile field ranging from 9 to 17 d and 1 to 3 d, respectively. Similar results were obtained for ground water. Adaptation was a key process in the system, as illustrated by the rapid biodegradation near the tile field and limited biodegradation at locations far downgradient or ungradient of the system, where little or no LAS or NTA loading occurred. The results demonstrate that properly functioning septic tank systems can effectively remove synthetic organic chemicals such as LAS and NTA.
Carbofuran residues in grasshoppers and vegetation from aerially sprayed prairie pastures: Potential effects on wildlife
Authors: Forsyth Douglas J. , Westcott Neil D.
Published: March 2010

Deposition and persistence of carbofuran in vegetation and grasshoppers of two prairie pastures were measured after single aerial applications at 134 g a.i per hectare in 1987 and 1988. Mean depositions on horizontal filter paper samplers were 43 1 and 64 9% of the nominal rate in the two applications Variability of deposits, measured as C V.s, were 76 4% and 86 9% Carbofuran residues in vegetation and grasshoppers were less variable than those in deposit samplers, with C V s of 40 6 and 70 6% in vegetation and 58 6 and 32 5% in grasshoppers for 1987 and 1988, respectively. Residues declined by 50% in 24 h both years from initial concentrations (3 h postspray) in vegetation of 13 3 and 10 8 μg/g Initial residues in grasshoppers averaged 2 2 μg/g in 1987 and 3.9 μg/g in 1988; the mean for both years was 2.5 μg/g Grasshoppers contained the same concentration of carbofuran 3 h after spraying, whether collected live or dead Maximum residues of 5 7 μg/g were found in grasshoppers from two of the 40 sites sampled in both years A model fitted to the data indicated that there may have been about a 24 to 44% loss of residues from vegetation, probably due to volatilization and other processes, before samples were collected at 3 h There was a decline in residues per grasshopper of 30% in 24 h both years, which was not evident when expressed as micrograms per gram because of desiccation of the dead insects The concentrations of carbofuran in the vegetation and grasshoppers were typical of aerial spraying, hence, they may be used as baseline values for estimating exposure of herbivores and msectivores to insecticide deposits from similar spray events by adjusting for rate of application Deposits measured on filter papers were positively related to concentrations in vegetation and grasshoppers Calculations of the potential effects on wildlife of ingesting sprayed grasshoppers, combined with other routes of exposure, indicated a relatively low hazard for herbivorous rodents but a relatively high hazard for insectivorous adult passerines and their young Monitoring passerines in a related field study did, however, not reveal any effects on survival within 3 d of spraying carbofuran.
Sublethal responses to pesticides of several species of australian freshwater fish and crustaceans and rainbow trout
Authors: Davies P.E. , Cook L.S.J. , Goenarso D.
Published: March 2010

Sublethal responses of the fish Oncorhynchus mykiss, Galaxias maculatus, Pseudaphritis urvillii, and the crustacean Paratya australiensis to short-term exposures to low concentrations of seven pesticides were compared under identical conditions. Parameters examined were hematocrit, leucocrit, plasma glucose, plasma protein, plasma chloride, muscle RNA and DNA, brain and muscle acetylcholinesterase activity, hepatic glutathione-S-transferase activity, hepatic glutathione, and somatic growth. The organisms were exposed to the following materials–the organophosphate insecticides acephate and fenitrothion; the phenoxyacetate herbicide MCPA-Na; the triazine herbicides atrazine and cyanazine; the fungicide chlorothalonil, and the pyrethroid insecticide cypermethrin–as purified active ingredients in continuous flow through at constant temperature (12–15°C) for 10 or 20 d, with feeding, at five concentrations. Oncorhynchus mykiss was marginally the most sensitive fish species studied in terms of the number of responses to pesticide exposure, but not in terms of the LOECs. Interspecies comparisons indicated that water quality criteria based on juvenile Oncorhynchus mykiss toxicity data alone would not be suitable for the protection of juvenile and adult Galaxias maculatus and Pseudaphritis urvillii from physiological stress in at least three of seven cases. Four of seven maximum acceptable toxicant concentrations (MATCs) derived from physiological responses of fish species resulted from data on Galaxias maculatus and Pseudaphritis urvillii alone. In the case of organophosphates, the decapod crustaceans Paratya australiensis and Astacopsis gouldi were by far the most sensitive. Tentative water quality criteria for the protection of study species from short-term stress are proposed.
Anaerobic biodegradation of halogenated and nonhalogenated N-, s-, and o-heterocyclic compounds in aquifer slurries
Authors: Adrian Neal R. , Suflita Joseph M.
Published: March 2010

The fate of several halogenated and nonhalogenated heterocyclic compounds in anoxic aquifer slurries was investigated Substrate depletion and methane formation were monitored in serum bottle incubations by HPLC and GC, respectively Pyridine, pyrimidine, thiophene, and furan were not mineralized following an 11-month incubation, but the corresponding carboxylated or oxygenated compounds were That is, >74% of the theoretically expected amount of methane was recovered from nicotinic acid, uracil, or 2-furoic acid Chlorinated derivatives, like 2 chloro- or 6-chloronicotinic acid, as well as 4 chloro- and 5-chlorouracil resisted mineralization However, 5-bromouracil was reductively dehalogenated to stoichiometric amounts of uracil, whereas 2-chloropyrimidine was metabolized to a more polar unidentified compound that resisted further anaerobic biodegradation Microorganisms acclimated to 5-bromouracil were unable to transform 4 chloro or 5 chlorouracil These findings illustrate how the structure of heterocyclic contaminants influences their susceptibility to anaerobic decay
Predation of ducks poisoned by white phosphorus: Exposure and risk to predators
Authors: Roebuck B.D. , Nam Sae-Im , Walsh Marianne E. , Racine Charles H. , Reitsma Leonard , Steele Ben
Published: March 2010

White phosphorus (P4) has been identified as the cause of mortality for dabbling ducks and swans at an estuanne salt marsh in Alaska Predation of ducks poisoned by P4 was monitored to assess the extent and range of predator exposures to P4 Avian tissues were analyzed for P4 by gas chromatography We observed that both sick and dead dabbling ducks were common prey of bald eagles (Hahaeetus leucocephalus), herring gulls (Larus argentatus), and common ravens (Corvus corax) Frank signs of P4 intoxication attracted predators and rendered the ducks easy prey White phosphorus was found in the tis sue remains of ducks that had been preyed upon, thus providing positive evidence that predators were exposed to P4 Although P4 varied widely among individuals, P4 was generally highest in the gizzard contents followed by fatty tissues such as fat depots and the skin White phosphorus was identified in fatty tissues of one eagle and in one herring gull egg, thus providing direct evidence of absorption of P4 by predators
Fate of silicone degradation products (silanols) in soil
Authors: Lehmann R.G. , Varaprath S. , Frye C.L.
Published: March 2010

Silicone (polydimethylsiloxane, or PDMS) fluids are widely used in industrial and consumer products and may find their way into municipal sludges that are eventually applied to the land. Earlier studies showed that PDMS degrades in soil to low-molecular-weight, water-soluble silanols of the formula HO–[Si(CH3)2O]n–H. In this study, 200-cs [14C]PDMS (1, 10, 100 mg kg−1) was placed in 50 g Londo sandy clay loam, and the soil was dried to generate the desired silanols in situ. The soil was remoistened and incubated at 25°C, 12% moisture, and 21% O2. The ultimate PDMS degradation product was identified by GC-MS as dimethylsilanediol. During the next 4 months, from 25 to 50% of this substance was either volatilized from the soil, incorporated into the humus, or to a lesser extent oxidized to 14CO2. The latter two processes increased with addition of alfalfa to the soil. No trend was seen in the loss of dimethylsilanediol over different concentrations.
Toxicity of metal-contaminated sediments from the upper clark fork river, montana, to aquatic invertebrates and fish in laboratory exposures
Authors: Kemble Nile E. , Brumbaugh William G. , Brunson Eric L. , Dwyer F. James , Ingersoll Chris G. , Monda Dave P. , Woodward Dan F.
Published: March 2010

Sediments of the upper Clark Fork River, from the Butte and Anaconda area to Milltown Reservoir (230 km downstream), are contaminated with As, Cd, Cu, Pb, Mn, and Zn primarily from mining activities. The toxicity of pore water from these sediments was determined using Daphnia magna (48-h exposure), rainbow trout (96-h exposure), and Microtox®. However, pore-water data from these exposures were questionable because of changes in the toxicity of pore-water samples after 5 to 7 d of storage. Whole-sediment tests were conducted with Hyalella azteca (28-d exposure), Chironomus riparius (14-d exposure), rainbow trout (Oncorhynchus mykiss) 21- to 28-d exposure and Daphnia magna (2- to 22-d exposure). Sediment samples from Milltown Reservoir and the Clark Fork River were not generally lethal to test organisms. However, both reduced growth and delayed sexual maturation of amphipods were associated with exposure to elevated concentrations of metals in sediments from the reservoir and river. Relative sensitivity (most sensitive to least sensitive) of organisms in whole-sediment toxicity tests was: Hyalella azteca > Chironomus riparius > rainbow trout > Daphnia magna. Relative sensitivity (most sensitive to least sensitive) of the three end points evaluated with Hyalella azteca was: length > sexual maturation > survival. The lack of lethal effects on organisms may be related to temporal differences in sediment, acid-volatile sulfide, or organic carbon.
Genetic variation in the temperature dependence of liver microsomal cyp2e1 activity, within and between species of the viviparous fish Poeciliopsis
Authors: Crivello Joseph F , Schultz R Jack
Published: March 2010

The temperature dependence of liver microsomal CYP2E1 (cytochrome P450 2E1) activity was examined in selected genotypes of the viviparous fish Poeciliopsis Activity of this enzyme, as a function of incubation temperature, was determined by measuring 6 OH-chlorzoxazone formation from chlorzoxazone, a specific CYP2E1 substrate Chlorzoxazone 6 hydroxylase activity was examined among five species of Poeciliopsis, as well as among nine genotypes within a species, P monacha Among Poeciliopsis genotypes, P monacha contained the greatest activity, 9 5 ± 1 5 U (where 1 U is defined as 1 μg 6 OH chlorzoxazone produced/min/mg protein, n = 6) with a temperature optimum (To) of 25°C The lowest activity was in P occidentalis, 0 65 ± 0 11 U, with a To of 27 to 28°C, P prolifica, P fasciata, P lucida, and P viriosa had intermediate levels of activities, 1 1 to 5 5 U, and To from 25 to 31°C To determine if metabolic differences exist within species, enzyme activity was examined from nine genotypes of P monacha by comparing expression among P monacha-lucida hybrids These hybrids were given identical paternal genomes of lucida but retained the original maternal monacha genomes sampled from wild gene pools The greatest activity was found in genotype T70 3 P Cw, 3 6 ± 0 1 U, at a To of 29°C, and the lowest was in genotype SV73 7s, 0 40 ± 0 12 U, at a To of 27°C The other naturally occurring genotypes, M65 24, M65–26 SV73 7v, as well as the laboratory produced synthetic hybrids, Syn4 and Syn5, had intermediate activities, 0 73 ± 0 38 to 2 1 ± 0 69 U, and To of 25 to 27°C No hybrid had activity levels as high as the maternal parent, P monacha, and only one had a To as low as either parent Apparently the genes involved in xenobiotic activity vary widely among the closely related species of Poeciliopsis but also within species suggesting that these phenotypes can be acted upon by natural selection
Snapping turtles (Chelydra serpentina) as biomonitors of lead contamination of the big river in missouri's old lead belt
Authors: Overmann Stephen R. , Krajicek James J.
Published: March 2010

The usefulness of common snapping turtles (Chelydra serpentina) as biomonitors of lead (Pb) contamination of aquatic ecosystems was assessed. Thirty-seven snapping turtles were collected from three sites on the Big River, an Ozarkian stream contaminated with Pb mine tailings. Morphometric measurements, tissue Pb concentrations (muscle, blood, bone, carapace, brain, and liver), δ-aminolevulinic acid dehydratase (δ-ALAD) activity, hematocrit, hemoglobin, plasma glucose, osmolality, and chloride ion content were measured. The data showed no effects of Pb contamination on capture success or morphological measurements. Tissue Pb concentrations were related to capture location. Hematocrit, plasma osmolality, plasma glucose, and plasma chloride ion content were not significantly different with respect to capture location. The δ-ALAD activity levels were decreased in turtles taken from contaminated sites. Lead levels in the Big River do not appear to be adversely affecting the snapping turtles of the river. Chelydra serpentina is a useful species for biomonitoring of Pb-contaminated aquatic environments.
The effects of motorway runoff on freshwater ecosystems: 1. Field study
Authors: Maltby Lorraine , Forrow David M. , Boxall Alistair B.A. , Calow Peter , Betton Clifford I.
Published: March 2010

The effects of motorway runoff on the water quality, sediment quality, and biota of small streams were investigated over a 12-month period. Downstream of motorway runoff discharges there was an increase in the sediment concentrations of total hydrocarbons, aromatic hydrocarbons, and heavy metals and an increase in the water concentrations of heavy metals and selected anions. Hydrocarbon contamination of sediments was positively correlated with potential contaminant loading (i.e., length of road drained/stream size). The greatest effect was observed at Pigeon Bridge Brook, a small stream receiving drainage from a 1,500-m stretch of the Ml motorway. The dominant PAHs in contaminated sediment at this site were phenanthrene, pyrene, and fluoranthene, whereas the dominant metals were zinc, cadmium, chromium, and lead. Differences between the station upstream and downstream of discharges in the diversity and composition of the macroinvertebrate assemblages were detected in four out of the seven streams surveyed. However, there was no evidence of an effect on either the diversity or abundance of epilithic algae. The diversity of the aquatic hyphomycete assemblage was only affected at the most impacted site. Reductions in macroinvertebrate diversity were associated with reductions in the processing of leaf litter and a change from an assemblage based on benthic algae and coarse particulate organic matter to one dependent upon fine particulate organic matter.
The importance of the exposure route when testing the toxicity of pesticides to saprotrophic isopods
Authors: Vink Karen , Tompot Anouk , Hermans Maartje , van Straalen Nico M. , Dewi Istiana , Bedaux Jack
Published: March 2010

When effects of pesticides are tested on nontarget invertebrates, substrate exposure is mostly used. Routes of uptake of pesticides by saprotrophic invertebrates may, however, also occur through the food, since the litter layer will be their main food source. These organisms live in close contact with the soil surface and litter layer. The ecotoxicity of the pesticides benomyl, carbofuran, and diazinon was investigated in a series of experiments. The toxicity was tested in lethal concentrations (leading to LC50 estimations), and sublethal concentrations leading to no-observed-effect concentration (NOEC) estimations on growth. Both substrate and dietary exposure were used to evaluate the most critical exposure route for each case. For food exposure, the chemicals were offered in ground leaves, while for substrate exposure the test organisms were kept on treated sand. Experiments were done with the tropical isopod Porcellionides pruinosus. For all three pesticides, substrate exposure was more critical than dietary exposure. The LC50 values (active ingredient per dry mass of food or soil) for benomyl, carbofuran, and diazinon, when mixed with food, were >31,000, 485, and 74.15 μg/g, respectively, and when mixed with sand 1,221, 21.41, and 3.03 μg/g, respectively. Sublethal effects on body growth were found for benomyl (NOEC = 1,000 μg/g) and diazinon (NOEC = <8.71 μg/g) after dietary exposure, but no effects were found in the course of the experiment for substrate exposure. Based on the results, it is concluded that the exposure route is of great importance for determining lethal effects as well as sublethal effects of pesticides on nontarget invertebrates in soil. The most critical exposure route depends both on the mode of action of the chemical and on the toxicological end point considered.
Biomonitoring of heavy metals in the pacific basin using avian feathers
Authors: Burger Joanna , Gochfeld Michael
Published: March 2010

We used avian feathers to biomonitor heavy-metal distribution in several areas in the Pacific Basin including Papua New Guinea, Australia, New Zealand, China, Johnston Atoll, Hawaii, and Costa Rica. This paper is a preliminary synthesis of data gathered by the Pacific Basin Biomonitoring Project. We examined levels of mercury, lead, cadmium, selenium, chromium, and manganese. For sooty terns (Sterna fuscata) and brown noddy (Anous stolidus) mercury levels were lower in the Pacific than in Puerto Rico in the Atlantic, but this was reversed for lead and cadmium. Adult birds had higher metal levels in their feathers than did young birds of the same species from the same area. Cadmium levels were higher in terrestrial species; lead, chromium, and manganese were highest in coastal species; and mercury and selenium were highest in marine species. Mercury levels were lowest in forest species, intermediate in species that eat insects and small vertebrates, and highest in species that eat intermediate to large fish. Lead levels were highest in species feeding in industrialized estuaries of Hong Kong.
Potency of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), alone and in combination with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), to produce lake trout early life-stage mortality
Authors: Zabel Erik W. , Cook Philip M. , Peterson Richard E.
Published: March 2010

Newly fertilized lake trout (Salvelinus namaycush) eggs were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), or their combination, and sac fry mortality was used to determine toxic potencies. The toxic equivalency factor (TEF) for PCB 126 was 0.0030. The dose-response curve for the PCB 126/TCDD mixture based on TCDD toxic equivalents was not significantly different from that for TCDD alone, suggesting additivity between the two congeners in causing sac fry mortality.
Monoaromatic hydrocarbon transformation under anaerobic conditions at seal beach, California: Laboratory studies
Authors: Ball Harold A. , Reinhard Martin
Published: March 2010

Anaerobic biotransformation of several aromatic hydrocarbons found in gasoline including benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene (BTEX) was studied in batch anaerobic laboratory microcosms. Aquifer sediment and ground water were obtained from the site of a historic gasoline spill at Seal Beach, California. Sulfate is present in the site ground water at 80 mg/ L, and sulfate-reducing activity appears to be the dominant intrinsic BTEX bioremediation process where nitrate is absent. In the laboratory, the microcosms were set up with different electron acceptors (sulfate and nitrate) in site ground water and various defined anaerobic media to estimate intrinsic biodegradation rates and to suggest conditions under which anaerobic bioremediation could be enhanced. In unamended microcosms, anaerobic biotransformation of toluene and m+p-xylene (m-xylene and p-xylene were measured as a summed parameter) occurred at a rate of 7.2 and 4.1 μg L−1 h−1, respectively, with sulfate as the apparent electron acceptor. Addition of nitrate stimulated nitrate-reducing conditions and increased rates of toluene and m+p-xylene biotransformation to 30.1 and 5.4 μg L−1 h−1, respectively. The catabolic substrate range was altered to include ethylbenzene in the nitrate-amended microcosms, suggesting an apparent preferential use of different BTEX compounds depending on the electron acceptor available. Under all the conditions studied, more than twice the amount of nitrate or sulfate was used than could be accounted for by the observed BTEX degradation. Benzene transformation was not observed under the conditions studied. Although methane was detected in microcosms prepared with anaerobic media lacking nitrate and sulfate, methanogenic biotransformation of BTEX compounds was not observed. The results of these experiments indicate that indigenous microorganisms from the Seal Beach aquifer have significant capability to degrade BTEX hydrocarbons and that intrinsic processes in the Seal Beach aquifer may remediate a portion of the hydrocarbon contamination in situ without intervention. However, the data also suggest that intervention by nitrate addition would enhance the rate and extent of anaerobic BTEX biotransformation.
Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the san Joaquin River and tributaries, California
Authors: Pereira Wilfred E. , Domagalski Joseph L. , Hostettler Frances D. , Brown Larry R. , Rapp John B.
Published: March 2010

A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the bivalve Corbicula fluminea. Results indicated that this river system is affected by agricultural practices and urban runoff.

Sediments from Dry Creek contained elevated concentrations of polycyclic aromatic hydrocarbons (PAHs), possibly derived from urban runoff from the city of Modesto; suspended sediments contained elevated amounts of chlordane. Trace levels of triazine herbicides atrazine and simazine were present in water at most sites. Sediments, water, and bivalves from Orestimba Creek, a westside tributary draining agricultural areas, contained the greatest levels of DDT (1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane), and its degradates DDD (1,1-dichloro-2,2-bis[p-chlorophenyl]ethane), and DDE (1,1-dichloro-2,2-bis[p-chlorophenyl]ethylene). Sediment adsorption coefficients (Koc), and bioconcentration factors (BCF) in Corbicula of DDT, DDD, and DDE at Orestimba Creek were greater than predicted values. Streams of the western San Joaquin Valley can potentially transport significant amounts of chlorinated pesticides to the San Joaquin River, the delta, and San Francisco Bay. Organochlorine compounds accumulate in bivalves and sediment and may pose a problem to other biotic species in this watershed.
Effects of the insecticide dursban® 4E (active ingredient chlorpyrifos) in outdoor experimental ditches: II. Invertebrate community responses and recovery
Authors: van den Brink Paul J. , Van Wijngaarden René P. A. , Lucassen Wil G. H. , Brock Theo C. M. , Leeuwangh Peter
Published: March 2010

This article describes the long-term effects on the macro invertebrate and zooplankton community in outdoor experimental ditches after a single application of the insecticide chlorpyrifos. Nominal concentrations of 0.1, 0.9, 6, and 44 μg/L of chlorpyrifos were applied to two mesocosms each, while four served as controls. Both macroinvertebrates and zooplankton were sampled from 4 weeks before to 55 weeks after treatment. The macroinvertebrate and zooplankton data sets were combined into one data set and analyzed using the multivariate ordination technique “redundancy analysis.” The method provided a clear description of the effects on the invertebrate community in time while still showing the effects at the species level. Crustacea and Insecta showed a rapid, concentration-dependent decrease in numbers after insecticide application (direct effects). An increase in gastropods and Oligochaeta was found, suggesting indirect effects. The start of recovery of the invertebrate populations affected was found to depend not only on the susceptibility of the taxa but also on ecological characteristics, such as the length of the life cycle. A no-observed-effect concentration of 0.1 μg/L could be derived both at the species and the community level. Safe concentrations, based on no-observed-short-term-effect levels for some characteristic indigenous taxa susceptible to chlorpyrifos, also appeared to protect the total invertebrate community in the long term. The invertebrate community at all treatment levels was considered to have recovered after 24 weeks posttreatment.
The natural petroleum hydrocarbon background in subtidal sediments of prince william sound, Alaska, USA
Authors: Page David S. , Boehm Paul D. , Douglas Gregory S. , Bence A. Edward , Burns William A. , Mankiewicz Paul J.
Published: March 2010

A natural regional petroleum hydrocarbon background has been identified in the subtidal sediments of Prince William Sound that is readily distinguished from Exxon Valdez spill oil by chemical fingerprinting methods. This hydrocarbon background is derived from natural petroleum seeps in the eastern Gulf of Alaska. The Alaska Coastal Current carries fine-grained sediments and associated hydrocarbons from seep areas to the east into Prince William Sound, where they are deposited on the seafloor. The analysis of age-dated sediment cores indicates that this process has been going on for the past 160 years, and probably for many thousands of years. In addition, results of a stratified random study of nearshore subtidal sediments conducted in 1990 show that this is a general phenomenon throughout the sound and is significant even in shallow water (3 to 30 m). For example, oleanane, a saturate petroleum biomarker found in Prince William Sound prespill background petroleum and seep sources but not in Exxon Valdez petroleum, is present in subtidal sediment samples from locations throughout the sound. This supports the conclusion that seep areas to the east are major sediment sources for the sound. Moreover, polycyclic aromatic hydrocarbon mixing model calculations show that, although Exxon Valdez spill-oil residues are present in nearshore subtidal sediments, they generally form a small increment on the natural background. The recognition of preexisting natural and anthropogenic hydrocarbon sources in a spill area is a fundamentally important component of any natural resource damage assessment.
Uptake of zinc by the midge larvae Chironomus riparius at different salinities: Role of speciation, acclimation, and calcium
Authors: Bervoets Lieven , Verheyen Rudolf , Blust Ronny
Published: March 2010

The uptake of zinc by the freshwater midge larvae Chironomus riparius was studied as a function of salinity. Fourth instar larvae were exposed to a salinity range up to 10‰ by diluting chemically defined seawater with chemically defined river water. The effect of prior acclimation at five different salinities on zinc uptake rate was examined. Solutions of different composition were tested to discriminate between the effect of the free zinc ion concentration, the free zinc ion activity, and the free calcium ion activity. Zinc uptake rate decreased with increasing salinity in all exposure solutions. Prior acclimation at salinities up to 10% did not influence zinc uptake rate. Changes in the free zinc ion activity explained most of the observed variation (58%). Changes in calcium ion activity had only a minor effect on zinc uptake (1%). Besides these effects the salinity of the exposure also influences the physiology of the larvae, altering zinc uptake when larvae are transferred from one salinity to another (6%). The combination of the different effects explained 65% of the total variation in zinc uptake by midge larvae. The remaining variation could not be explained by the experimental design and was attributed to natural variation in zinc uptake among midge larvae.
Assessment of chemical fate in the environment using evaluative, regional and local-scale models: Illustrative application to chlorobenzene and linear alkylbenzene sulfonates
Authors: Mackay Donald , Di Guardo Antonio , Paterson Sally , Kicsi Gabriel , Cowan Christina E. , Kane David M.
Published: March 2010

Evaluation of chemical fate in the environment has been suggested to be best accomplished using a five-stage process in which a sequence of increasing site-specific multimedia mass balance models is applied. This approach is illustrated for chlorobenzene and linear alkylbenzene sulfonates (LAS). The first two stages involve classifying the chemical and quantifying the emissions into each environmental compartment. In the third stage, the characteristics of the chemical are determined using the evaluative equilibrium criterion model, which is capable of treating a variety of chemicals including those that are involatile and insoluble in water. This evaluation is conducted in three steps using levels I, II, and III versions of the model, which introduce increasing complexity and more realistic representations of the environment. In the fourth stage, ChemCAN, which is a level III model for specific regions of Canada, is used to predict the chemical's fate in southern Ontario. The final stage is to apply local environmental models to predict environmental exposure concentrations. For chlorobenzene, the local model was the SoilFug model, which predicts the fate of agro-chemicals, and for LAS the WW-TREAT, GRiDS, and ROUT models were used to predict the fate of LAS in a sewage treatment plant and in riverine receiving waters. It is concluded that this systematic approach provides a comprehensive assessment of chemical fate, revealing the broad characteristics of chemical behavior and quantifying the likely local and regional exposure levels.
Predicting the toxicity of metal-spiked laboratory sediments using acid-volatile sulfide and interstitial water normalizations
Authors: Berry W.J. , Hansen D.J. , Boothman W.S. , Mahony J.D. , Robson D.L. , Di Toro D.M. , Shipley B.P. , Rogers B. , Corbin J.M.
Published: March 2010

Numerous studies have shown that dry weight concentrations of metals in sediments cannot be used to predict toxicity across sediments. However, several studies using sediments from both freshwater and saltwater have shown that interstitial water concentration or normalizations involving acid-volatile sulfide (AVS) can be used to predict toxicity in sediments contaminated with cadmium, copper, nickel, lead, or zinc across a wide range of sediment types. Six separate experiments were conducted in which two or three sediments of varying AVS concentration were spiked with a series of concentrations of cadmium, copper, lead, nickel, or zinc or a mixture of four of these metals. The amphipod Ampelisca abdita was then exposed to the sediments in 10-d toxicity tests. Amphipod mortality was sediment dependent when plotted against dry weight metals concentration but was not sediment dependent when plotted against simultaneously extracted metal (SEM)/AVS or interstitial water toxic units (IWTUs). Sediments with SEM/AVS ratios <1.0 were seldom (2.3%) toxic (i.e., caused <24% mortality), while sediments with SEM/AVS ratios >1.0 were frequently (80%) toxic. Similarly, sediments with <0.5 IWTU were seldom toxic (3.0%), while sediments with >0.5 IWTU were toxic 94.4% of the time. These results, coupled with results from related studies, demonstrate that an understanding of the fundamental chemical reactions which control the availability of cadmium, copper, lead, nickel, and zinc in sediments can be used to explain observed biological responses. We believe that using SEM/AVS ratios and IWTUs allows for more accurate predictions of acute mortality, with better causal linkage to metal concentration, than is possible with sediment evaluation tools which rely on dry weight metal concentrations.
Measurements of pesticide spray drift deposition into field boundaries and hedgerows: 2. Autumn applications
Authors: Longley Martin , Sotherton Nicolas W
Published: March 2010

Tractor spray applications of a pyrethroid insecticide combined with a fluorescent tracer were applied to cereal field edges on four separate occasions in the autumn. Spray drift measurements were made in field boundaries adjacent to conventionally sprayed and 6-m-wide unsprayed “Conservation Headlands,” which act as buffer zones designed to keep the outermost edge of the crop unsprayed with certain pesticide groups. The volume of drifting spray reaching field boundaries was dependent upon wind conditions and was significantly reduced by the use of these buffer zones. Comparisons of spray drift are made with comparable experiments carried out in summer cereals (reported in an accompanying paper). In a separate experiment, high mortalities of Spodoptera littoralis Boisd. larvae were recorded when they were exposed to grasses collected from hedge bottoms adjacent to conventionally sprayed headlands, and from additional spray applications made with a hand-held sprayer (used to simulate the levels of drift recorded in field trials). Larval mortalities were reduced, but still detectable, when grasses contaminated with drift adjacent to Conservation Headlands were bioassayed. In light of these findings, the current recommendation of these 6-m-wide buffer zones in cereals is discussed.
Calcium fluxes in juvenile tilapia, Oreochromis mossambicus, exposed to sublethal waterborne Cd, Cu or mixtures of these metals
Authors: Pelgrom Sylvia M G J , Lock Robert A C , Balm Paul H M , Bonga Sjoerd E Wendelaar
Published: March 2010

In juvenile tilapia the effects of waterborne Cu, Cd, and combinations of these metals on whole-body Ca fluxes were studied, using 45Ca as tracer. The maintenance of Ca homeostasis in fish is crucial throughout life but is especially important in young fish; Ca is also critical for growth. Single metal exposure had no effect on Ca fluxes after 6 d of exposure. In fish coexposed to 200 μg Cu L−1 + 70 μg Cd L−1 however, Ca influx was significantly decreased, whereas Ca efflux was not affected. As a result, the net flux was decreased. Because the effect on Ca fluxes observed in Cu/Cd-coexposed fish could not have been predicted from the effects of single metal exposures, this study underscores the impact of interactions between toxicants. Because natural freshwaters are commonly polluted by mixtures of metals, interactions between toxicants are important in risk assessment of heavy metals.
Toxic potencies of extracts of sediment and settling particulate matter collected in the recipient of a bleached pulp mill effluent before and after abandoning chlorine bleaching
Authors: Engwall Magnus , Broman Dag , Dencker Lennart , Näf Carina , Zebühr Yngve , Brunström Björn
Published: March 2010

Extracts of bottom sediment and settling particulate matter (SPM) samples collected in the recipient water body of a bleached pulp mill effluent were separated into three fractions: monoaromatic/aliphatic compounds, diaromatic compounds (e.g., polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans), and polyaromatic compounds (e.g., polycyclic aromatic hydrocarbons [PAHs]). The fractions were then tested for dioxinlike potency. The methods used for the assessment of dioxinlike potency were an in vitro assay, based on the induction of 7-ethoxyresorufin-O-deethylase (EROD) in chicken embryo livers, a test for EROD induction in ovo using chicken embryos, and an immunotoxicity test measuring inhibition of lymphoid cell development in cultured fetal mouse thymuses. The samples collected closest to the mill were the most potent. There was a time-dependent decrease in dioxinlike potency in the SPM samples collected near the mill, which coincided with the cessation of chlorine gas bleaching at the mill. The bioassays in general, and the in vitro chicken embryo liver bioassay in particular, proved useful in the assessment of dioxinlike compounds in the sediment and SPM samples. The polyaromatic fractions of the samples were generally more potent than the diaromatic fractions. Only a small part of the effects caused by the polyaromatic fractions could be explained by 15 analyzed PAHs, indicating the presence of unquantified polyaromatic compounds with dioxinlike effects. This investigation indicates that the cessation of chlorine bleaching in the pulp mill resulted in a reduced load of diaromatic dioxinlike compounds in the recipient water body.
Effects of embryonic and adult exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin on hepatic microsomal testosterone hydroxylase activities in great blue herons (Ardea herodias)
Authors: Sanderson J Thomas , Janz David M , Bellward Gail D , Giesy John P
Published: March 2010

In a continuing effort to evaluate biomarkers of exposure of great blue herons (Ardea herodias) to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related halogenated aromatic hydrocarbons, we examined the effect of TCDD on hepatic microsomal testosterone hydroxylase activities. Heron embryos were exposed in ovo to 2 μg TCDD/kg egg (or corn oil vehicle) and sacrificed at hatch or 7 d posthatch. Adult herons were exposed intraperitoneally to 20 μg TCDD/kg and sacrificed 2 weeks later. The sex of the birds was known for the adults only. Hepatic microsomes of herons of each age group were able to hydroxylate testosterone at the 2β, 6β, 15α, 16α, or 16β positions. In 7-d-old chicks, an additional unidentified compound was formed. The age of the untreated herons had a strong influence on the activities of the five hydroxylases, with changes of up to 17-fold. The TCDD significantly (p < 0.05) induced 2β-, 6β-, and 15α-testosterone hydroxylase activities in the adult females, 15α- in the adult males, and 6β-testosterone hydroxylase activity in the hatchlings. In the 7-d-old chicks, induction was no longer apparent. A significant correlation existed between hepatic microsomal ethoxyresorufin O-deethylase (EROD) and 6β-testosterone hydroxylase activity in hatchlings (r = 0.91; n = 12) and adult female herons (r = 1.0; n = 4). The TCDD-induced changes in testosterone hydroxylase activities occurred at doses that resulted in tissue concentrations and levels of EROD induction that were environmentally relevant, but did not result in overt toxicities.
Inability of bacteria to degrade low concentrations of toluene in water
Authors: Roch François , Alexander Martin
Published: March 2010

Microbial utilization of low concentrations of toluene in water was investigated. When bacteria that were not actively degrading toluene were incubated in solutions containing 2.1 to 11 μg of toluene/L, the concentrations remaining in solution after 8 d ranged from 0.69 to 0.99 μg/L. However, when the initial concentration was ≥31 μg/L, the concentration remaining was <0.2 μg/L. When bacteria actively degrading toluene were inoculated into solutions containing 0.9 μg of toluene/L, the concentration remaining after 8 d was 79 ng/L. We propose that the inability of some bacteria to maintain or attain high metabolic activity on a compound present at low concentrations may prevent its rapid degradation in natural environments.
Effects of triphenyltin and pH on the growth and development ofRana lessonaeandRana esculentatadpoles
Authors: Fioramonti Ennio , Semlitsch Raymond D , Reyer Heinz-Ulrich , Fent Karl
Published: March 2010

We tested the s sceptibility of parental (Rana lessonae) and hemiclonal hybrid tadpoles of the R. esculenta complex to triphenyltin (TPT), a fungicide commonly used in agriculture, at renewed concentrations of 0.11, 0.81, and 1.87 μg/L over the entire larval period. Because habitats of R. lessonae are often characterized by a low pH and disturbed habitats such as gravel pits by high pH, we also tested whether pH 6.4 or pH 8.1 modifies their susceptibility to triphenyltin. We measured survival to metamorphosis, body mass at day 30, body mass at metamorphosis, and time to metamorphosis of individually reared tadpoles. Crosses of R. lessonae males with R. lessonae females and with two hemiclones of R. esculenta females produced tadpoles of R. lessonae, R. esculenta (GUT1) and R. esculenta (GUT2). At increasing triphenyltin concentrations, survival and growth rate decreased and time to metamorphosis increased. The GUT1 larvae of R. esculenta were the least and larvae of R. lessonae the most sensitive. The GUT2 larvae of R. esculenta were intermediate in sensitivity. The effect of pH also depended on the genotype. Tadpoles of R. lessonae had a higher growth rate and a shorter larval period at pH 6.4. The pH effect on tadpoles of R. esculenta was slight, but growth rate was lower and larval period longer at pH 6.4. Because TPT most strongly affected the larval period, exposure to TPT could decrease survival in natural ponds because of the increased risk of predation in permanent ponds or desiccation in drying ponds as well as the increased risk of additional chemical exposure. Our results indicate that the sexual parental species R. lessonae is more sensitive to environmental chemicals such as triphenyltin than is the hemiclonal hybrid R. esculenta.
Depuration and uptake kinetics of I, Cs, Mn, Zn and Cd by the earthworm (Lumbricus terrestris) in radiotracer-spiked litter
Authors: Sheppard Steve C , Evenden William G , Cornwell Teresa C
Published: March 2010

The relative depuration and uptake kinetics of contaminants should be known to interpret appropriately the use of organisms such as earthworms in environmental bioassays and monitoring. For example, 14-d earthworm bioassays should be interpreted with the knowledge that some contaminants will continue to accumulate in tissues for months. The radiotracers 125I, 134Cs, 54Mn, 65Zn, and 109Cd were applied to deciduous litter and specimens of Lumbricus terrestris were exposed, either to litter alone or to litter on the top of soil columns. Depuration was monitored for 120 d and uptake, in a separate experiment, for 20 d. Both depuration and uptake were described using two-phase, first-order statistical models. Gut clearance had a mean half-time of 1.4 d. The mean half-time for physiological depuration decreased from I (210 d) > Cd (150 d) > Zn (69 d) > Mn (40 d) > Cs (24 d). Both the depuration and the uptake experiments were necessary to resolve even partially the multiphase processes. Earthworm/soil dry weight concentration ratios decreased from Cd > Zn > I ≥ Cs ≥ Mn. The very slow kinetics indicate that tissue concentrations will increase continuously for a long time, with important implications for subsequent food-chain transfers.