Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| dna structures common for chironomid telomeres terminating with complex repeats. | tandem repeats, 340 bp long, have been shown to terminate the chromosomes in chironomus pallidivittatus and similar dna may be used for this purpose by related insects. in view of the importance of chironomus in telomere studies, representing in principle a third system after short repeats and drosophila telomeric retrotransposons, we have investigated the related chironomus dilutus, to learn what dna structures are conserved at the chromosome ends. interspersed subrepeats in the telomeric repea ... | 2000 | 10886419 |
| identifying primary stressors impacting macroinvertebrates in the salinas river (california, usa): relative effects of pesticides and suspended particles. | laboratory dose-response experiments with organophosphate and pyrethroid pesticides, and dose-response experiments with increasing particle loads were used to determine which of these stressors were likely responsible for the toxicity and macroinvertebrate impacts previously observed in the salinas river. experiments were conducted with the amphipod hyalella azteca, the baetid mayfly procloeon sp., and the midge chironomus dilutus (shobanov, formerly chironomus tentans). the results indicate the ... | 2006 | 16225973 |
| assessment of diazinon toxicity in sediment and water of constructed wetlands using deployed corbicula fluminea and laboratory testing. | constructed wetlands for mitigation of nonpoint agricultural runoff have been assessed for their ability to decrease potential toxicity from associated contaminants. after a simulated runoff event, constructed wetlands positioned in series were used to measure the effects of the organophosphate insecticide diazinon. water, sediment, and plant samples from five sites were analyzed for diazinon concentrations from 0.5 hours to 26 days; peak concentrations were measured in sediment after 0.5 hours ... | 2007 | 17549545 |
| effects of low dissolved oxygen on organisms used in freshwater sediment toxicity tests. | minimum dissolved oxygen requirements are part of standard guidelines for toxicity testing of freshwater sediments with several benthic invertebrates, but the data underlying these requirements are somewhat sparse. we exposed three common test organisms to ranges of dissolved oxygen concentrations to determine their responses in 10-d exposures, relative to published guidelines for sediment toxicity tests. the oligochaete, lumbriculus variegatus, showed 100% survival in all exposures down to the ... | 2008 | 17870143 |
| assessing caffeine as an emerging environmental concern using conventional approaches. | organic wastewater contaminants, including pharmaceuticals, caffeine, and nicotine, have received increased scrutiny because of their detection in water bodies receiving wastewater discharge. despite recent measurement in united states streams, caffeine's effect on freshwater organisms is not well documented. the present study measured caffeine's lethal and sublethal effects on the freshwater species, ceriodaphnia dubia, pimephales promelas, and chironomus dilutus. these organisms, which are use ... | 2008 | 17957400 |
| biological and chemical characterization of metal bioavailability in sediments from lake roosevelt, columbia river, washington, usa. | we studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from lake roosevelt (lr), a reservoir on the columbia river in washington, usa that receives inputs of metals from an upstream smelter facility. we characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the columbia river, six sites in the reservoir, and a reference site in an uncontaminated ... | 2008 | 18060524 |
| aquatic fate and effects of bacillus thuringiensis cry3bb1 protein: toward risk assessment. | genetically engineered crops expressing bacillus thuringiensis (bt) insecticidal crystalline (cry) proteins became commercially available in the united states in 1996. in 2006, 19 million ha of bt corn were planted worldwide, which represents a 10 million ha increase in 10 years. the sustainability of bt crops is important, because their use has significantly reduced the amount of chemical insecticides necessary to control agricultural pests. despite the high adoption rates of this novel insecti ... | 2008 | 18333682 |
| evaluation of a polyacrylamide soil additive to reduce agricultural-associated contamination. | polyacrylamide is an effective water treatment product used to reduce suspended sediment and associated contaminants. an anionic polyacrylamide-containing product was tested for sediment and associated contaminant reduction and potential toxicity in agricultural irrigation and rainfall runoff. the product effectively reduced turbidity, total suspended solids, and phosphate concentrations in the field when compared to the untreated runoff waters. acute survival of ceriodaphnia dubia and pimephale ... | 2008 | 18463774 |
| using the sediment quality triad to characterize baseline conditions in the anacostia river, washington, dc, usa. | the sediment quality triad (sqt) consists of complementary measures of sediment chemistry, benthic community structure, and sediment toxicity. we applied the sqt at 20 stations in the tidal portion of the anacostia river from bladensburg, md to washington, dc to establish a baseline of conditions to evaluate the effects of management actions. sediment toxicity was assessed using 10-day survival and growth tests with the freshwater amphipod, hyalella azteca and the midge, chironomus dilutus. trip ... | 2009 | 18677546 |
| temperature as a toxicity identification evaluation tool for pyrethroid insecticides: toxicokinetic confirmation. | toxicity identification evaluation (tie) methods can be used to identify toxic compounds in environmental samples using a variety of laboratory techniques. whereas ties exist for nonpolar organics, relatively few methods are established for individual contaminant classes. toxicity identification evaluations have shown pesticides to be the cause of toxicity in agricultural waters and effluents, and more recent studies have shown that the insecticide class of concern is pyrethroids. the primary ob ... | 2009 | 19071969 |
| toxicity of anionic polyacrylamide formulations when used for erosion control in agriculture. | addition of anionic polyacrylamide (pam) to agricultural irrigation water can dramatically reduce erosion of soils. however, the toxicity of pam to aquatic life, while often claimed to be low, has not been thoroughly evaluated. five pam formulations, including two oil-based products, one water-based product, one granular product and one tablet product, were evaluated for acute and/or chronic toxicity to five species commonly used for freshwater toxicity testing [hyalella azteca (saussure), chiro ... | 2010 | 19141814 |
| an inducible hsp70 gene from the midge chironomus dilutus: characterization and transcription profile under environmental stress. | in the present study, we identified and characterized an inducible heat shock protein 70 (hsp70) from the midge chironomus dilutus and investigated the transcriptional profile of the gene under baseline and environmentally stressful conditions. using real-time quantitative reverse transcriptase-polymerase chain reaction (qrt-pcr), we observed increased expression of cd-hsp70-1 in response to both heat shock and copper stress. we also investigated the expression of this gene during midge developm ... | 2009 | 19196349 |
| analysis of pyrethroid insecticides in chironomus dilutus using matrix solid phase dispersion extraction. | a matrix solid phase dispersion method was developed to detect eight pyrethroid insecticides in the aquatic invertebrate, chironomus dilutus. a mixture of silica gel, diatomaceous earth and primary/secondary amino solid absorbents were selected as the dispersion matrix, while 7% ethyl ether in hexane was used as the elution solvent. method detection limits for the target pyrethroids ranged from 0.46 to 4.4 microg kg(-1), and recoveries were 63.5%-124.0%, 43.7%-116.0% and 53.1%-93.1% at spiked le ... | 2009 | 19458879 |
| joint toxicity of fluoranthene and pentachlorobenzene to hyalella azteca and chironomus dilutus. | nonpolar organic chemicals such as polycyclic aromatic hydrocarbons and chlorobenzenes are expected to act additively when exposed as a mixture. the present study examined the toxicity of fluoranthene (flu) and pentachlorobenzene (pcbz) individually and in a binary mixture using the whole-body residue as the dose metric. body residues were based on the toxic equivalent body residue, which included the parent compound plus the organically extractable metabolites for flu and the parent compound on ... | 2009 | 19674768 |
| determining modifications to bifenthrin toxicity and sediment binding affinity from varying potassium chloride concentrations in overlying water. | bifenthrin, a current-use pyrethroid insecticide, has been repeatedly identified as a major contributor to toxicity in urban and residential stream sediment. within an urban stream multiple stressors exist. however, other than pesticides, the influence of secondary stressors on bifenthrin toxicity has not been studied. the goal of this project was to study how dissolved ions, based on the model salt kcl, influence bifenthrin toxicity. the presence of these dissolved ions could influence bifenthr ... | 2010 | 20403629 |
| chronic toxicity of fluorotelomer acids to daphnia magna and chironomus dilutus. | saturated and unsaturated fluorotelomer carboxylic acids (fluorotelomer acids: ftas) represent important intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (pfcas). recent studies have detected ftas at low concentrations (ng/l) in precipitation and surface waters; however, information regarding chronic toxicity is lacking. the present study assessed the chronic toxicity of the 8:2 saturated fluorotelomer carboxylic acid (8:2 ftca) to chironomus dilutus ... | 2010 | 20821548 |
| chronic toxicity of chloride to freshwater species: effects of hardness and implications for water quality guidelines. | toxicity tests using nine freshwater species (ceriodaphnia dubia, daphnia magna, oncorhynchus mykiss, pimephales promelas, lumbriculus variegatus, tubifex tubifex, chironomus dilutus, hyallela azteca, and brachionus calyciflorus) were conducted to evaluate their sensitivity to chloride. acute-to-chronic ratios (acrs) from these tests indicate the acr of 7.59 employed by the united states environmental protection agency (u.s. epa) in deriving its water quality guideline for chloride may be conser ... | 2011 | 20872898 |
| toxicity of sediment-associated pesticides to chironomus dilutus and hyalella azteca. | two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated central valley of california, united states. pyrethroid insecticides were the main contributors to the observed toxicity. however, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. hundreds of pesticides are currently used in the central valley of california, but only a ... | 2011 | 21052987 |
| identifying the causes of sediment-associated toxicity in urban waterways of the pearl river delta, china. | twenty-one sediments collected in urban waterways of the pearl river delta (prd) in china were screened for acute toxicity using chironomus dilutus in addition to being examined for potential contributors of sediment toxicity, including 19 organochlorine, five organophosphate, and nine pyrethroid insecticides, 28 polycyclic aromatic hydrocarbons, 27 polychlorinated biphenyls, 15 polybrominated diphenyl ethers, 12 metals, and ammonia. fifteen of the 21 sediments exhibited acute toxicity to c. dil ... | 2011 | 21291230 |
| toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures. | silicon carbide nanowires (sicnw) are insoluble in water. when released into an aquatic environment, sicnw would likely accumulate in sediment. the objective of this study was to assess the toxicity of sicnw to four freshwater sediment-dwelling organisms: amphipods (hyalella azteca), midges (chironomus dilutus), oligochaetes (lumbriculus variegatus), and mussels (lampsilis siliquoidea). amphipods were exposed to either sonicated or nonsonicated sicnw in water (1.0 g/l) for 48 h. midges, mussels, ... | 2011 | 21305577 |
| effects of fluidized gas desulfurization (fgd) gypsum on non-target freshwater and sediment dwelling organisms. | fluidized gas desulfurization gypsum is a popular agricultural soil amendment used to increase calcium and sulfur contents, and reduce aluminum toxicity. due to its surface application in conservation tillage systems and high solubility, the soluble components of gypsum may be transferred with agricultural runoff into receiving waters. the current study measured toxicity of gypsum to ceriodaphnia dubia, pimephales promelas, chironomus dilutus, and hyalella azteca. solutions at 2,400 mg gypsum/l ... | 2011 | 21431885 |
| toxicity of uranium, molybdenum, nickel, and arsenic to hyalella azteca and chironomus dilutus in water-only and spiked-sediment toxicity tests. | a series of laboratory spiked-sediment toxicity tests with the amphipod hyalella azteca and the midge chironomus dilutus were undertaken to determine acute and chronic toxicity thresholds for uranium (u), molybdenum (mo), nickel (ni), and arsenic (as) based on both whole-sediment (total) and pore water exposure concentrations. water-only toxicity data were also generated from separate experiments to determine the toxicities of these metals/metalloids under our test conditions and to help evaluat ... | 2011 | 21529943 |
| pyrethroid insecticides in urban salmon streams of the pacific northwest. | urban streams of the pacific northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. sediments from oregon and washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. approximately one-third o ... | 2011 | 21592636 |
| examining the effects of metal mining mixtures on fathead minnow (pimephales promelas) using field-based multi-trophic artificial streams. | this study illustrates the use of a mesocosm approach for assessing the independent effects of three treated metal mine effluents (mme) discharging into a common receiving environment and regulated under the same regulation. a field-based, multi-trophic artificial stream study was conducted in august 2008 to assess the effects of three metal mining effluents on fathead minnow (pimephales promelas) in a 21-day reproduction bioassay. the nature of the approach allowed for assessment of both dietar ... | 2011 | 21621843 |
| selenium bioaccumulation and speciation in chironomus dilutus exposed to water-borne selenate, selenite, or seleno-dl-methionine. | the objective of the present study was to describe the uptake and elimination kinetics of selenium (se) administered in the forms of selenate, selenite, and selenomethionine (seleno-dl-methionine) in different life stages of the midge chironomus dilutus, and to determine the relationship between se bioavailability and se speciation using x-ray absorption spectroscopy (xas). midge larvae exposed to 4.3 µg/l as dissolved selenate for 10 d of had negligible accumulation of se (indistinguishable fro ... | 2011 | 21766323 |
| examining waterborne and dietborne routes of exposure and their contribution to biological response patterns in fathead minnow (pimephales promelas). | the objectives of the current study were: (i) to gain a better understanding of the relative importance of water and diet as routes of exposure causing toxicity in fathead minnow (fhm) exposed to metal mining effluents (mme) using a full factorial water/food experimental design (experiment 1), and (ii) to assess differences in the effects of food quality on toxicity by comparing fhm fed both a live and frozen diet of chironomus dilutus (experiment 2). the results showed significant increases in ... | 2011 | 21888872 |
| joint toxicity of a pyrethroid insecticide, cypermethrin, and a heavy metal, lead, to the benthic invertebrate chironomus dilutus. | insecticides and heavy metals are frequently detected in the environment, but few studies have assessed the joint toxicity of organic and inorganic contaminants. joint toxicity of a pyrethroid insecticide, cypermethrin, and a heavy metal, pb(2+), was evaluated in the present study. an antagonistic toxic response was observed when the benthic invertebrate chironomus dilutus was simultaneously exposed to the two contaminants in both water and sediment exposures. pre-exposure bioassays with midges ... | 2011 | 21935981 |
| effectiveness of ozonation treatment in eliminating toxicity of oil sands process-affected water to chironomus dilutus. | water soluble organic compounds (ocs), including naphthenic acids (nas), are potentially toxic constituents of oil sands process-affected water (ospw) that is generated during extraction of bitumen from alberta oil sands. ozonation can decrease concentrations of ocs in ospw. however, effects of ozonated-ospw on multicellular organisms are unknown. a 10-day and a chronic exposure of chironomus dilutus to ospw were conducted to assess effects on survival, growth, development, and behavior. two sep ... | 2012 | 21992611 |
| behaviour of pharmaceuticals in spiked lake sediments - effects and interactions with benthic invertebrates. | the behaviour and effects of atorvastatin (ato), carbamazepine (cbz), and 17α-ethinylestradiol (ee2) were investigated in spiked lake sediments, at concentrations up to 56.5 mg kg(-1)dry weight (dw), with the benthic invertebrates chironomus dilutus and hyalella azteca. desorption constants were calculated in the presence and absence of animals, using linear isotherms, yielding k(d) values of 28.2, 189.0 and 125.1 l kg(-1) (ato), 73.7, 201.7 and 263.2 l kg(-1) (cbz), and 114.9, 114.2 and 519.2 l ... | 2012 | 22154156 |
| toxicity of sediment-associated unresolved complex mixture and its impact on bioavailability of polycyclic aromatic hydrocarbons. | unresolved complex mixtures (ucms) and polycyclic aromatic hydrocarbons (pahs) are ubiquitous in sediment originating from oil leaks, shipping, and other human activities and thus it is necessary to understand the role of ucm on sediment toxicity and pah bioaccumulation. in the current study, lethal and sublethal effects of sediment-associated ucm were examined in two benthic invertebrates (chironomus dilutus and lumbriculus variegatus) using two spiked sediments. results showed that ucm alone w ... | 2011 | 22197560 |
| effects of exposure to oil sands process-affected water from experimental reclamation ponds on chironomus dilutus. | effective detoxification of oil sands process-affected water (ospw) is one issue associated with bitumen extraction in the alberta oil sands. it has been suggested that reclamation ponds can be used to passively treat ospw, potentially allowing for its safe return to the environment. in this study, ospw was sampled in two batches (a and b) from the syncrude canada ltd. west in-pit (wip) settling pond and from three experimental reclamation ponds - big pit, fe5, and tpw. acute (10 d) and chronic ... | 2012 | 22265614 |
| laboratory toxicity and benthic invertebrate field colonization of upper columbia river sediments: finding adverse effects using multiple lines of evidence. | from 1930 to 1995, the upper columbia river (ucr) of northeast washington state received approximately 12 million metric tons of smelter slag and associated effluents from a large smelter facility located in trail, british columbia, approximately 10 km north of the united states-canadian border. studies conducted during the past two decades have demonstrated the presence of toxic concentrations of heavy metals in slag-based sandy sediments, including cadmium, copper, zinc, and lead in the ucr ar ... | 2012 | 22402778 |
| selenium speciation and localization in chironomids from lakes receiving treated metal mine effluent. | a lake system in northern saskatchewan receiving treated metal mine and mill effluent contains elevated levels of selenium (se). an important step in the trophic transfer of se is the bioaccumulation of se by benthic invertebrates, especially primary consumers serving as a food source for higher trophic level organisms. chironomids, ubiquitous components of many northern aquatic ecosystems, were sampled at lakes downstream of the milling operation and were found to contain se concentrations rang ... | 2012 | 22608132 |
| toxicity of carbon nanotubes to freshwater aquatic invertebrates. | carbon nanotubes (cnts) are hydrophobic in nature and thus tend to accumulate in sediments if released into aquatic environments. as part of our overall effort to examine the toxicity of carbon-based nanomaterials to sediment-dwelling invertebrates, we have evaluated the toxicity of different types of cnts in 14-d water-only exposures to an amphipod (hyalella azteca), a midge (chironomus dilutus), an oligochaete (lumbriculus variegatus), and a mussel (villosa iris) in advance of conducting whole ... | 2012 | 22610786 |
| use of solid phase microextraction to estimate toxicity: relating fiber concentrations to toxicity--part i. | use of solid-phase microextraction (spme) fibers as a dose metric for toxicity testing was evaluated for hydrophobic pesticides to the midge chironomus dilutus and the amphipod hyalella azteca. test compounds included p,p'-dichlorodiphenyltrichloroethane (p,p'-ddt), p,p'-dichlorodiphenyldichloroethane (p,p'-ddd), p,p'-dichlorodiphenyldichloroethylene (p,p'-dde), permethrin, bifenthrin, tefluthrin, and chlorpyrifos. acute water toxicity tests were determined for 4- and 10-d exposures in both spec ... | 2012 | 22767390 |
| single versus combined lethal effects of three agricultural insecticides on larvae of the freshwater insect chironomus dilutus. | pesticides are currently regulated individually but are present in aquatic systems as mixtures of toxicants. in this study, the lethal effects of three agricultural insecticides--chlorpyrifos, imidacloprid and dimethoate--on chironomus dilutus larvae were examined. ninety-six-hour static bioassays were performed using single, binary, and ternary toxicant mixtures. the effects of the binary mixtures were investigated using the mixtox model to determine if the mixtures behaved additively, synergis ... | 2012 | 22772597 |
| use of solid phase microextraction to estimate toxicity: relating fiber concentrations to body residues--part ii. | in the companion paper, solid phase microextraction (spme) fiber concentrations were used as a dose metric to evaluate the toxicity of hydrophobic pesticides, and concentration-response relationships were found for the hydrophobic pesticides tested in the two test species. the present study extends the use of fiber concentrations to organism body residues to specifically address biotransformation and provide the link to toxic response. test compounds included the organochlorines p,p'-dichlorodip ... | 2012 | 22786796 |
| identifying the cause of sediment toxicity in agricultural sediments: the role of pyrethroids and nine seldom-measured hydrophobic pesticides. | few currently used agricultural pesticides are routinely monitored for in the environment. even if concentrations are known, sediment lc(50) values are often lacking for common sediment toxicity testing species. to help fill this data gap, sediments in california's central valley were tested for nine hydrophobic pesticides seldom analyzed: abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin. most were detected, but rarely at conc ... | 2013 | 22832339 |
| chronic toxicity of tire and road wear particles to water- and sediment-dwelling organisms. | tire and road wear particles (trwp) consist of a complex mixture of rubber, and pavement released from tires during use on road surfaces. subsequent transport of the trwp into freshwater sediments has raised some concern about the potential adverse effects on aquatic organisms. previous studies have shown some potential for toxicity for tread particles, however, toxicity studies of trwp collected from a road simulator system revealed no acute toxicity to green algae, daphnids, or fathead minnows ... | 2013 | 23001428 |
| toxicity of sediments potentially contaminated by coal mining and natural gas extraction to unionid mussels and commonly tested benthic invertebrates. | sediment toxicity tests were conducted to assess potential effects of contaminants associated with coal mining or natural gas extraction activities in the upper tennessee river basin and eastern cumberland river basin in the united states. test species included two unionid mussels (rainbow mussel, villosa iris, and wavy-rayed lampmussel, lampsilis fasciola, 28-d exposures), and the commonly tested amphipod, hyalella azteca (28-d exposure) and midge, chironomus dilutus (10-d exposure). sediments ... | 2013 | 23071077 |
| bioavailability-based toxicity endpoints of bifenthrin for hyalella azteca and chironomus dilutus. | recent studies have determined that techniques, such as solid phase microextraction (spme) fibers and tenax beads, can predict bioaccumulation and potentially could predict toxicity for several compounds and species. toxicity of bifenthrin was determined using two standard sediment toxicity tests with the benthic species hyalella azteca and chironomus dilutus in three reference sediments with different characteristics. the objectives of the current study were to establish bioavailability-based m ... | 2013 | 23084260 |
| assessing bioavailability and toxicity of permethrin and ddt in sediment using matrix solid phase microextraction. | matrix solid phase microextraction (matrix-spme) was evaluated as a surrogate for the absorbed dose in organisms to estimate bioavailability and toxicity of permethrin and dichlorodiphenyltrichloroethane (ddt) in laboratory-spiked sediment. sediments were incubated for 7, 28, and 90 days at room temperature to characterize the effect of aging on bioavailability and toxicity. sediment toxicity was assessed using two freshwater invertebrates, the midge chironomus dilutus and amphipod hyalella azte ... | 2013 | 23086182 |
| contaminants in stream sediments from seven united states metropolitan areas: part ii--sediment toxicity to the amphipod hyalella azteca and the midge chironomus dilutus. | relationships between sediment toxicity and sediment chemistry were evaluated for 98 samples collected from seven metropolitan study areas across the united states. sediment-toxicity tests were conducted with the amphipod hyalella azteca (28 day exposures) and with the midge chironomus dilutus (10 day exposures). overall, 33 % of the samples were toxic to amphipods and 12 % of the samples were toxic to midge based on comparisons with reference conditions within each study area. significant corre ... | 2013 | 23129064 |
| bioavailability, toxicity and biotransformation of selenium in midge (chironomus dilutus) larvae exposed via water or diet to elemental selenium particles, selenite, or selenized algae. | elemental selenium (se) is generally considered to be biologically inert due to its insolubility in water. it is a common form of se in sediment near uranium mining and milling operations in northern saskatchewan, canada. nanosized particles of many materials exhibit different properties compared with their bulk phases, in some cases posing health and ecological risks. here we investigated the bioavailability and toxicity of se nanoparticles (senps) using 10-day waterborne and dietary exposures ... | 2013 | 23234498 |
| sediment-associated pesticides in an urban stream in guangzhou, china: implication of a shift in pesticide use patterns. | pesticide use patterns in china have changed in recent years; however, the study of the environmental fate of current-use pesticides (cups) and their ecotoxicological significance in aquatic ecosystems is limited. in the present study, sediments were collected from an urban stream in the chinese city of guangzhou. sediment-associated legacy organochlorine pesticides and cups-including organophosphates, pyrethroids, fipronil, and abamectin-were analyzed. additionally, the relative toxicity of the ... | 2013 | 23377859 |
| bioavailability-based chronic toxicity measurements of permethrin to chironomus dilutus. | compared with acute toxicity, chronic exposures to low levels of contaminants are more environmentally relevant, but fewer data are available. in the present study, sediment toxicity of the pyrethoid permethrin to chironomus dilutus was determined. the whole-life-cycle toxicity testing was conducted with the endpoints covering survival, growth, emergence, and reproduction. permethrin caused 50% lethality in c. dilutus at 1.83 ± 1.13 µg/g organic carbon (oc) and 1.20 ± 0.55 µg/g oc after exposure ... | 2013 | 23424028 |
| the influence of food quantity on metal bioaccumulation and reproduction in fathead minnows (pimephales promelas) during chronic exposures to a metal mine effluent. | metal mine effluents can impact fish in the receiving environment via both direct effects from exposure as well as indirect effects via food web. the main objective of the present study was to assess whether an indirect effect such as reduced food (prey) availability could influence metal accumulation and reproductive capacity in fish during chronic exposure to a metal mine effluent. breeding pairs of fathead minnows (pimephales promelas) were exposed to either reference water (rw) or an environ ... | 2013 | 23453348 |
| chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments. | this study evaluated the chronic toxicity of ni-spiked freshwater sediments to benthic invertebrates. a 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (avs; 0.94-38 µmol/g) and total organic carbon (toc; 0.42-10%). chronic sediment toxicity tests were conducted with 8 invertebrates (hyalella azteca, gammarus pseudolimnaeus, chironomus ... | 2013 | 23657897 |
| influence of elevated alkalinity and natural organic matter (nom) on tissue-specific metal accumulation and reproductive performance in fathead minnows during chronic, multi-trophic exposures to a metal mine effluent. | metal bioavailability in aquatic organisms is known to be influenced by various water chemistry parameters. the present study examined the influence of alkalinity and natural organic matter (nom) on tissue-specific metal accumulation and reproductive performance of fathead minnows (pimephales promelas) during environmentally relevant chronic exposures to a metal mine effluent (mme). sodium bicarbonate (nahco3) or nom (as commercial humic acid) were added to a canadian mme [45 percent process wat ... | 2013 | 23790591 |
| effects of environmentally realistic daily temperature variation on pesticide toxicity to aquatic invertebrates. | the toxicity of several agricultural chemicals to aquatic invertebrates has been shown to be temperature-dependent, but the role of daily temperature variation has rarely been examined. the authors simulated a natural daily temperature pattern (a fluctuating cycle of 21 °c to 31 °c over a 24-h period) based on field-collected data from southern high plains wetlands (tx, usa) and conducted a series of experiments comparing responses from this exposure scenario to a constant exposure at 24 ± 1 °c. ... | 2013 | 23955707 |
| improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments. | within the framework of european union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. in the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (avs) and total organic carbon. the following species were tested: amphipods (hyalella azteca, gammarus pseudolimnaeus), mayflies (hexagenia ... | 2013 | 23983116 |
| an in situ assessment of selenium bioaccumulation from water-, sediment-, and dietary-exposure pathways using caged chironomus dilutus larvae. | an in situ caging study was conducted downstream of a metal mine in northern canada to determine the significance of surface water versus sediment exposure on selenium (se) bioaccumulation in the benthic invertebrate chironomus dilutus. laboratory-reared c. dilutus larvae were exposed to either site-specific whole-sediment and surface water or surface water only for 10 d at sites with differing sediment and se characteristics. results showed elevated whole-body se concentrations in c. dilutus la ... | 2013 | 23996699 |
| endocrine disruption and oxidative stress in larvae of chironomus dilutus following short-term exposure to fresh or aged oil sands process-affected water. | understanding the toxicity of oil sands process-affected water (ospw) is a significant issue associated with the production of oil from the alberta oil sands. ospw is acutely and chronically toxic to organisms, including larvae of chironomus dilutus. in this study, fresh ospw ('wip-ospw') was collected from the west in-pit settling pond and aged ospw ('fe5-ospw') was collected from the fe5 experimental reclamation pond, both of which are located on the syncrude canada ltd. lease site near fort m ... | 2013 | 24096237 |
| dissipation of insecticidal cry1ac protein and its toxicity to nontarget aquatic organisms. | the widespread cultivation of bacillus thuringiensis crops has raised public concerns on their risk to nontarget organisms. persistence of cry1ac protein in soil, sediment and water and its toxicity to nontarget aquatic organisms were determined. the dissipation of cry1ac toxin was well described using first order kinetics, with the half-lives (dt50) ranging from 0.8 to 3.2, 2.1 to 7.6 and 11.0 to 15.8 d in soil, sediment and water, respectively. microbial degradation played a key role in the di ... | 2013 | 24151928 |
| toxicity of the insecticide fipronil and its degradates to benthic macroinvertebrates of urban streams. | fipronil is a phenylpyrazole insecticide with increasing urban use. sixteen urban waterways and municipal wastewater were sampled for fipronil, its environmental degradates, and pyrethroid insecticides. because findings could not be interpreted with existing data on fipronil degradate toxicity, ec50s and lc50s for fipronil and its sulfide and sulfone derivatives were determined for 14 macroinvertebrate species. four species were more sensitive than any previously studied, indicating fipronil's t ... | 2014 | 24368023 |
| using hexagenia in sediment bioassays: methods, applicability, and relative sensitivity. | the majority of sediment toxicity and aquatic bioaccumulation assessments are conducted using standardized species, such as hyalella azteca, chironomus dilutus, and lumbriculus variegatus. the burrowing mayfly, hexagenia sp., may serve as an ideal supplemental organism for both toxicity and bioaccumulation studies for several reasons. hexagenia are recognized as sensitive species, have a long aquatic life stage (up to 2 yr), and have large bodies, which aid in retrieval from sediments and for re ... | 2014 | 24375636 |
| comparative effects of sediment versus aqueous polychlorinated biphenyl (pcb) exposure on benthic and planktonic invertebrates. | polychlorinated biphenyls (pcbs) are an environmental concern because of their adverse effects on humans and wildlife, and understanding the contribution of various matrices (i.e., sediment and water) to pcb exposure on aquatic communities is critical for successful remediation of impacted sites. the present study examined the toxicity of different routes of pcb exposure in aquatic invertebrates. in complementary laboratory and field experiments, the authors compared the effects of aqueous versu ... | 2014 | 24464368 |
| chronic toxicity thresholds for sediment-associated benzo[a]pyrene in the midge (chironomus dilutus). | polycyclic aromatic hydrocarbons (pahs) are ubiquitous in aquatic ecosystems and have been shown to be one of the causes of sediment toxicity to benthic invertebrates. benzo[a]pyrene (bap) was selected as a representative for the pah family of compounds for developing chronic sediment toxicity thresholds for chironomus dilutus. life-cycle toxicity testing was initiated using newly hatched midge larvae and terminated until hatch of the second generation. median lethal concentrations were 92.5 ± 1 ... | 2014 | 24553811 |
| species sensitivity and dependence on exposure conditions impacting the phototoxicity of tio₂ nanoparticles to benthic organisms. | toxicity of titanium dioxide nanoparticles (nano-tio2 ) to aquatic organisms can be greatly increased after exposure to ultraviolet (uv) radiation. this phenomenon has received some attention for water column species; however, investigations of nano-tio2 phototoxicity for benthic organisms are still limited. in the present study, bioassays of 3 representative benthic organisms (hyalella azteca, lumbriculus variegatus, and chironomus dilutus) were conducted to evaluate nano-tio2 phototoxicity. wh ... | 2014 | 24846372 |
| evaluation of metals, metalloids, and ash mixture toxicity using sediment toxicity testing. | in december 2008, a release of 4.1 million m(3) of coal ash from the tennessee valley authority kingston fossil plant occurred. ash washed into the emory river and migrated downstream into the clinch and tennessee rivers. a baseline ecological risk assessment evaluated risks to ecological receptors from ash in the river system post-dredging. this article describes the approach used and results from sediment toxicity tests, discussing any causal relationships between ash, metals, and toxicity. li ... | 2015 | 25125279 |
| occurrence and toxicity of sediment-associated contaminants in guangzhou college city and its adjacent areas: the relationship to urbanization. | guangzhou college city in the southeast of guangzhou, china, became a home to 10 universities in 2003 after a largely agricultural past. the city has since experienced rapid urbanization with limited development of adjacent areas. twenty-one sediment samples were collected in the city and its adjacent areas to evaluate the influence of urbanization in different functional zones on sediment quality in local waterways. sediment toxicity was assessed by 10-day toxicity tests using two benthic inver ... | 2015 | 25362564 |
| fate and effects of clothianidin in fields using conservation practices. | despite the extensive use of the neonicotinoid insecticide clothianidin, and its known toxicity to beneficial insects such as pollinators, little attention has been given to its fate under agricultural field conditions. the present study investigated the fate and toxicity of clothianidin applied every other year as a corn seed-coating at 2 different rates, 0.25 mg/seed and 0.50 mg/seed, in an agricultural field undergoing a corn-soybean annual rotation, and conservation tillage. concentrations w ... | 2015 | 25376402 |
| toxicity of sediments from lead-zinc mining areas to juvenile freshwater mussels (lampsilis siliquoidea) compared to standard test organisms. | sediment toxicity tests compared chronic effects on survival, growth, and biomass of juvenile freshwater mussels (28-d exposures with lampsilis siliquoidea) to the responses of standard test organisms-amphipods (28-d exposures with hyalella azteca) and midges (10-d exposures with chironomus dilutus)-in sediments from 2 lead-zinc mining areas: the tri-state mining district and southeast missouri mining district. mussel tests were conducted in sediments sieved to <0.25 mm to facilitate recovery of ... | 2015 | 25545632 |
| the use of growth and behavioral endpoints to assess the effects of pesticide mixtures upon aquatic organisms. | aquatic communities are often subject to complex contaminant mixtures, usually at sublethal concentrations, that can cause long-term detrimental effects. chemicals within mixtures can effectively interact, resulting in synergism, antagonism or additivity. we investigated the tertiary mixture effects of two pyrethroids, lambda-cyhalothrin and permethrin, and the organophosphate chlorpyrifos, evaluating sublethal endpoints; immobility and growth, on chironomus dilutus in 10-day exposures. we utili ... | 2015 | 25630500 |
| relative sensitivity of an amphipod hyalella azteca, a midge chironomus dilutus, and a unionid mussel lampsilis siliquoidea to a toxic sediment. | the objective of the present study was to evaluate the relative sensitivity of test organisms in exposures to dilutions of a highly toxic sediment contaminated with metals and organic compounds. one dilution series was prepared using control sand (low total organic carbon [toc; <0.1%, low binding capacity for contaminants]) and a second dilution series was prepared using control sediment from west bearskin lake, minnesota, usa (high toc [∼10% toc, higher binding capacity for contaminants]). test ... | 2015 | 25655578 |
| toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors. | the present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with hyalella azteca and oncorhynchus mykiss. chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. ... | 2015 | 25732700 |
| identifying the causes of sediment-associated toxicity in urban waterways in south china: incorporating bioavailabillity-based measurements into whole-sediment toxicity identification evaluation. | sediments in urban waterways of guangzhou, china, were contaminated by a variety of chemicals and showed prevalent toxicity to benthic organisms. a combination of whole-sediment toxicity identification evaluation (tie) and bioavailability-based extraction was used to identify the causes of sediment toxicity. of the 6 sediment samples collected, 4 caused 100% mortality to chironomus dilutus in 10-d bioassays, and the potential toxicants were assessed using tie in these sediments after dilution. t ... | 2015 | 25753920 |
| responses of lyngbya wollei to algaecide exposures and a risk characterization associated with their use. | to make informed decisions regarding management of noxious algal growths, water resource managers require information on responses of target and non-target species to algaecide exposures. periodic treatments of phycomycin®-scp (sodium carbonate peroxyhydrate) followed by algimycin®-pwf (gluconate and citrate chelated copper) to control lyngbya wollei growths for ten years provided an opportunity for a risk evaluation of treated coves in lay lake, al. abiotic sediment characteristics (acid solubl ... | 2015 | 25770656 |
| a comparison of the sublethal and lethal toxicity of four pesticides in hyalella azteca and chironomus dilutus. | laboratory toxicity testing is the primary tool used for surface water environmental risk assessment; however, there are critical information gaps regarding the sublethal effects of pesticides. in 10-day exposures, we assessed the lethal and sublethal (motility and growth) toxicities of four commonly used pesticides, bifenthrin, permethrin, cyfluthrin, and chlorpyrifos, on two freshwater invertebrates, chironomus dilutus and hyalella azteca. pyrethroids were more toxic than the organophosphate c ... | 2015 | 25804662 |
| stormwater-related transport of the insecticides bifenthrin, fipronil, imidacloprid, and chlorpyrifos into a tidal wetland, san francisco bay, california. | suisun marsh, in northern san francisco bay, is the largest brackish marsh in california, and provides critical habitat for many fish species. storm runoff enters the marsh through many creeks that drain agricultural uplands and the urban areas of fairfield and suisun city. five creeks were sampled throughout a major storm event in february 2014, and analyzed for representatives of several major insecticide classes. concentrations were greatest in creeks with urban influence, though sampling was ... | 2015 | 25956145 |
| assessment of sediment risk in the north end of tai lake, china: integrating chemical analysis and chronic toxicity testing with chironomus dilutus. | whole life-cycle bioassays with chironomus dilutus were performed to evaluate sediment toxicity in tai lake, a typical freshwater lake in china. meanwhile, contaminants of concern were analyzed in sediment. the sediments in tai lake showed no acute mortality in 10-day testing to c. dilutus. after chronic exposure to the sediments, however, adverse effects-including decreased survival and sublethal impairments of growth, emergence, and fecundity-were observed at most sites in tai lake. a variety ... | 2015 | 26003187 |
| integrated sediment quality assessment through biomarker responses and bioavailability measurements: application in tai lake, china. | a weight of evidence (woe) framework has been applied to assess sediment quality of a typical freshwater lake, tai lake in china, where the sediments were contaminated by various chemicals but showed no acute lethality to the benthic invertebrate, chironomus dilutus. a quantitative scoring method was employed to integrate three lines of evidence (loe), including adverse effects in life cycle bioassays, biomarker responses, and bioavailability-based chemical analysis. six biomarkers were determin ... | 2015 | 26004354 |
| acute and chronic toxicity of sodium sulfate to four freshwater organisms in water-only exposures. | the acute and chronic toxicity of sulfate (tested as sodium sulfate) was determined in diluted well water (hardness of 100 mg/l and ph 8.2) with a cladoceran (ceriodaphnia dubia; 2-d and 7-d exposures), a midge (chironomus dilutus; 4-d and 41-d exposures), a unionid mussel (pink mucket, lampsilis abrupta; 4-d and 28-d exposures), and a fish (fathead minnow, pimephales promelas; 4-d and 34-d exposures). among the 4 species, the cladoceran and mussel were acutely more sensitive to sulfate than the ... | 2016 | 26139383 |
| macroinvertebrate responses to nickel in multisystem exposures. | metals introduced to sediments undergo a variety of complexation and partitioning changes that affect metal bioavailability. using simultaneously extracted metal (sem)/acid volatile sulfide (avs) and organic carbon (f(oc)) models, the authors examined nickel (ni) toxicity and bioavailability in 2 field studies (using streamside mesocosm and in situ colonization) and 1 laboratory study. the streamside mesocosm experiments indicated that benthic communities (ephemeroptera, abundance, and taxa rich ... | 2016 | 26178528 |
| effects of clay minerals and organic matter in formulated sediments on the bioavailability of sediment-associated uranium to the freshwater midge, chironomus dilutus. | it is well established that bioavailability influences metal toxicity in aquatic ecosystems. however, the factors and mechanisms that influence uranium (u) bioavailability and toxicity in sediment have not been thoroughly evaluated, despite evidence that suggests different sediment components can influence the sorption and interaction of some metals. given that dissolved u is generally accepted as being the primary bioavailable fraction of u, it is hypothesized that adsorption and interaction of ... | 2015 | 26205073 |
| joint toxicity of sediment-associated permethrin and cadmium to chironomus dilutus: the role of bioavailability and enzymatic activities. | pyrethroid insecticides and metals commonly co-occurred in sediment and caused toxicity to benthic organisms jointly. to improve accuracy in assessing risk of the sediments contaminated by insecticides and metals, it is of great importance to understand interaction between the contaminants and reasons for the interaction. in the current study, permethrin and cadmium were chosen as representative contaminants to study joint toxicity of pyrethroids and metals to a benthic invertebrate chironomus d ... | 2015 | 26367707 |
| a long-term assessment of pesticide mixture effects on aquatic invertebrate communities. | to understand the potential effects of pesticide mixtures on aquatic ecosystems, studies that incorporate increased ecological relevance are crucial. using outdoor mesocosms, the authors examined long-term effects on aquatic invertebrate communities of tertiary mixtures of commonly used pesticides: 2 pyrethroids (permethrin, λ-cyhalothrin) and an organophosphate (chlorpyrifos). application scenarios were based on environmentally relevant concentrations and stepwise increases of lethal concentrat ... | 2016 | 26565581 |
| sediment properties influencing the bioavailability of uranium to chironomus dilutus larvae in spiked field sediments. | the partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. little research has been done examining the effects of sediment properties on the bioavailability of uranium (u) to freshwater benthic invertebrates. in the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) wer ... | 2016 | 26802266 |
| development and application of freshwater sediment-toxicity benchmarks for currently used pesticides. | sediment-toxicity benchmarks are needed to interpret the biological significance of currently used pesticides detected in whole sediments. two types of freshwater sediment benchmarks for pesticides were developed using spiked-sediment bioassay (ssb) data from the literature. these benchmarks can be used to interpret sediment-toxicity data or to assess the potential toxicity of pesticides in whole sediment. the likely effect benchmark (leb) defines a pesticide concentration in whole sediment abov ... | 2016 | 26851756 |
| comparative responses of freshwater organisms to exposures of a commercial naphthenic acid. | comparative toxicity studies using unconfounded exposures can prioritize the selection of sensitive sentinel test species and refine methods for evaluating ecological risks of complex mixtures like naphthenic acids (nas), a group of organic acids associated with crude oils and energy-derived waters that have been a source of aquatic toxicity. the objectives of this study were to compare responses of freshwater aquatic organisms (vertebrate, invertebrates, and a macrophyte; in terms of acute toxi ... | 0 | 27016812 |
| using a modified dredging elutriate testing approach to evaluate potential aquatic impacts associated with dredging a large freshwater industrial harbor. | potential adverse impacts to the aquatic environment should be minimized whenever possible during an environmental dredging project by selecting realistic and technically feasible environmental targets. these targets need to balance short term impacts with the longer term benefit of removing contaminated sediments from the environment. environmental dredging is part of the planned remediation of randle reef (a 60 hectare zone of mostly pah-contaminated sediments) in hamilton, ontario, canada. in ... | 2017 | 27144596 |
| bioswales reduce contaminants associated with toxicity in urban storm water. | contamination and toxicity associated with urban storm water runoff are a growing concern because of the potential impacts on receiving systems. california water regulators are mandating implementation of green infrastructure as part of new urban development projects to treat storm water and increase infiltration. parking lot bioswales are low impact development practices that promote filtering of runoff through plants and soil. studies have demonstrated that bioswales reduce concentrations of s ... | 2016 | 27145488 |
| comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to chironomus dilutus and estimation of toxic equivalency factors. | nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. in the present study, full life-cycle toxicity tests ... | 2017 | 27329202 |
| interactions between bt crops and aquatic ecosystems: a review. | the term bt crops collectively refers to crops that have been genetically modified to include a gene (or genes) sourced from bacillus thuringiensis (bt) bacteria. these genes confer the ability to produce proteins toxic to certain insect pests. the interaction between bt crops and adjacent aquatic ecosystems has received limited attention in research and risk assessment, despite the fact that some bt crops have been in commercial use for 20 yr. reports of effects on aquatic organisms such as dap ... | 2016 | 27530353 |
| does cadmium affect the toxicokinetics of permethrin in chironomus dilutus at sublethal level? evidence of enzymatic activity and gene expression. | pyrethroids and metals were simultaneously detected in aquatic environment and showed antagonistic lethality to the benthic invertebrate, chironomus dilutus. accelerated biotransformation of pyrethroids in organism by the presence of metals was proposed as the likely reason for the antagonism. mechanistic explanation for the role of toxicokinetics of pyrethroids in the antagonistic interaction would help better understanding the reasons for the joint toxicity. the goal was achieved in the curren ... | 2016 | 27567170 |
| evaluation of the effect of water type on the toxicity of nitrate to aquatic organisms. | a suite of acute and chronic toxicity tests were conducted to evaluate the sensitivity of freshwater organisms to nitrate (as sodium nitrate). acute exposures with rainbow trout (onchorhynchus mykiss) and amphipods (hyalella azteca), as well as chronic exposures with h. azteca (14-d survival and growth), midges (chironomus dilutus; 10-d survival and growth), daphnids (ceriodaphnia dubia; 7-d survival and reproduction), and fathead minnows (pimephales promelas; 7-d survival and growth) were used ... | 2017 | 27810544 |
| primary sources and toxicity of pahs in milwaukee-area streambed sediment. | high concentrations of polycyclic aromatic hydrocarbons (pahs) in streams can be a significant stressor to aquatic organisms. to understand the likely sources and toxicity of pahs in milwaukee-area streams, streambed sediment samples from 40 sites and parking lot dust samples from 6 sites were analyzed for 38 parent pahs and 25 alkylated pahs. diagnostic ratios, profile correlations, principal components analysis, source-receptor modeling, and mass fractions analysis were used to identify potent ... | 2017 | 27883232 |
| chronic toxicity of azoxystrobin to freshwater amphipods, midges, cladocerans, and mussels in water-only exposures. | understanding the effects of fungicides on nontarget organisms at realistic concentrations and exposure durations is vital for determining potential impacts on aquatic ecosystems. environmental concentrations of the fungicide azoxystrobin have been reported up to 4.6 μg/l in the united states and 30 μg/l in europe. the objective of the present study was to evaluate the chronic toxicity of azoxystrobin in water-only exposures with an amphipod (hyalella azteca; 42-d exposure), a midge (chironomus ... | 2017 | 28181697 |
| effect-directed analysis of toxicants in sediment with combined passive dosing and in vivo toxicity testing. | identifying key toxicants in sediment is a great challenge, particularly if nontarget toxicants are involved. to identify the contaminants responsible for sediment toxicity to chironomus dilutus in guangzhou reach of the pearl river in south china, passive dosing and in vivo toxicity testing were incorporated into effect-directed analysis (eda) to account for bioavailability. fractionation of sediment extracts was performed with gel permeation chromatography and reverse phase liquid chromatograp ... | 2017 | 28448143 |
| using chironomus dilutus to identify toxicants and evaluate the ecotoxicity of sediments in the haihe river basin. | to effectively manage a watershed and successfully restore a river system, it is very important to assess the toxicity of sediments and identify the substances causing the toxicity. seventy-six sediments collected in the haihe river basin (hrb) in china were screened for acute toxicity using chironomus dilutus. we found that sediments from more than 32% of sampling sites, distributed mainly in the ziya tributary and along the estuary, were acutely toxic to midges. a toxicity identification evalu ... | 2017 | 28469260 |
| influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the midwestern usa. | simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. these three measures were evaluated at 99 wadable stream sites across 11 states in the midwestern united states during the summer of 2013 to assess sediment pollution across a large agricultural landscape. this evaluation considers an extensive suite of sediment chemistry t ... | 2017 | 28531955 |
| cumulative toxicity of neonicotinoid insecticide mixtures to chironomus dilutus under acute exposure scenarios. | extensive agricultural use of neonicotinoid insecticide products has resulted in the presence of neonicotinoid mixtures in surface waters worldwide. although many aquatic insect species are known to be sensitive to neonicotinoids, the impact of neonicotinoid mixtures is poorly understood. in the present study, the cumulative toxicities of binary and ternary mixtures of select neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) were characterized under acute (96-h) exposure scenarios us ... | 2017 | 28636110 |
| estimation of vanadium water quality benchmarks for the protection of aquatic life with relevance to the athabasca oil sands region using species sensitivity distributions. | elevated vanadium (v) concentrations in oil sands coke, which is produced and stored on site of some major athabasca oil sands companies, could pose a risk to aquatic ecosystems in northern alberta, canada, depending on its future storage and utilization. in the present study, v toxicity was determined in reconstituted athabasca river water to various freshwater organisms, including 2 midge species (chironomus dilutus and chironomus riparius; 4-d and 30-d to 40-d exposures) and 2 freshwater fish ... | 2017 | 28636253 |
| contribution of pyrethroids in large urban rivers to sediment toxicity assessed with benthic invertebrates chironomus dilutus: a case study in south china. | the importance of pyrethroids as potential stressors to benthic organisms has gradually become evident in urban creeks; however, the occurrence and toxicity of sediment-associated pyrethroids are rarely studied in large rivers. in this context, 10 sediments from a large urban river (guangzhou reach of the pearl river in china) were assessed for pyrethroid occurrence and sediment toxicity to the benthic invertebrate chironomus dilutus. one half of the sediments exhibited lethality to c. dilutus i ... | 2017 | 28722781 |
| changing patterns in water toxicity associated with current use pesticides in three california agriculture regions. | regulation of agriculture irrigation water discharges in california, usa, is assessed and controlled by its 9 regional water quality control boards under the jurisdiction of the california state water resources control board. each regional water board has developed programs to control pesticides in runoff as part of the waste discharge requirements implemented through each region's irrigated lands regulatory program. the present study assessed how pesticide use patterns differ in the imperial (i ... | 2017 | 29139620 |
| predicting the bioavailability of sediment-bound uranium to the freshwater midge (chironomus dilutus) using physicochemical properties. | assessment of uranium (u)-contaminated sediment is often hindered by the inability to accurately account for the physicochemical properties of sediment that modify u bioavailability. the goal of this research was to determine whether sediment-associated u bioavailability could be predicted over a wide range of conditions and sediment properties using simple regressions and a geochemical speciation model, the windermere humic aqueous model (wham7). data from u-contaminated field sediment bioaccum ... | 2017 | 29236329 |
| acute toxicity of six neonicotinoid insecticides to freshwater invertebrates. | neonicotinoids are a group of insecticides commonly used in agriculture. due to their high water solubility, neonicotinoids can be transported to surface waters and have the potential to be toxic to aquatic life. the present study assessed and compared the acute (48 or 96 h) toxicity of 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) to 21 laboratory-cultured and field-collected aquatic invertebrates spanning 10 aquatic arthropod orders. tes ... | 2018 | 29336495 |