| an ultrastructural study of the larval integument of the midge, chironomus riparius meigen (diptera: chironomidae). | the larval integument of the midge, chironomus riparius mg., is unusually thin although it conforms with the normal insect pattern. the cuticle of the post-cephalic segments is about 3 micrometer thick and overlies an epidermis which has an irregular basal plasma membrane resulting in spaces occurring between it and the basement membrane. the ventral tubuli have a similar epidermis but the cuticle is somewhat thinner. the anal papillae have the thinnest cuticular covering with a uniquely folded ... | 1978 | 627023 |
| the ultrastructure of the non-neurosecretory components in the brain of the midge, chironomus riparious mg. (diptera: nematocera). | the ultrastruct of the neural sheath, glial cells and neurons in the brain of the neoimaginal male chironomus riparius is described. the neural sheath comprises a neural lamella and underlying perineurium. the neural lamella consists of an amorphous matrix in which fine fibrils occur. the perineurium is composed of two cell types forming a continuous layer around the brain. the subjacent cortical layer, composed of the cell bodies of neurons and glial cells, varies considerably in thickness and ... | 1978 | 630602 |
| a structural study of the anal papillae of the midge chironomus riparius meigen (diptera: chironomidae). | larvae of the midge, chironomus riparius mg., have four anal papillae arranged as two pairs, one dorsal to and the other ventral to the anus. structural study with light and electron microscopes has revealed that their integument consists of a thin cuticle overlaying a thick, syncytial epidermis which is specialised to facilitate ion transport. there is a distinct neck or collar region at the junction of each papilla with the rest of the body wall. although in many respects these structures rese ... | 1976 | 1253247 |
| toxicity of lindane to freshwater insect larvae in compartments of an experimental pond. | the acute and chronic toxicities of lindane to larvae of the freshwater insects chironomus riparius meigen, chaoborus flavicans (meigen), and sigara striata (l.) were investigated in mesocosm compartments of an experimental pond. the following median lethal concentrations (lc50s) were determined: 240-hr lc50 of 2.0 micrograms lindane liter-1 for second instar c. riparius, 72-hr lc50 of 6.5 micrograms lindane liter-1 for fourth instar c. riparius, and 96-hr lc50s of 4.0 and 3.9 micrograms lindane ... | 1992 | 1375150 |
| distribution and control of chironomus riparius (diptera: chironomidae) in a polluted creek. | mass emergences of adult chironomus riparius have been regularly occurring in late february near residential areas adjacent to a creek receiving municipal sewage effluent located in lexington, kentucky. prior to attempting control of this chironomid, the larval distribution of this species in the creek was investigated. although large numbers of larvae were being produced in this creek, the greatest larval density occurred downstream from an adjacent horse "muck" pile and an adjacent landfill. a ... | 1992 | 1431860 |
| toxicity of four common pollutants to the freshwater macroinvertebrates chironomus riparius meigen (insecta:diptera) and gammarus pulex (l.) (crustacea: amphipoda). | the lethal toxicities of the four pollutants 3,4-dichloroaniline (dca), atrazine, copper, and lindane were determined for the 2nd larval instar of the insect chironomus riparius meigen and the juvenile stage (2nd or 3rd moult) of the crustacean gammarus pulex (l.). median lethal concentrations (lc50s) were determined over a 240 h test period. the order of toxicity of the test chemicals is different for each species. for c. riparius, lindane was the most toxic, followed by copper, dca, and atrazi ... | 1991 | 1719943 |
| effect of sediment contact and uptake mechanisms on accumulation of three chlorinated hydrocarbons in the midge, chironomus riparius. | | 1990 | 2111718 |
| evidence for haemoglobins as common allergenic determinants in ige-mediated hypersensitivity to chironomids (non-biting midges). | chironomids (non-biting midges) are known to cause ige-mediated hypersensitivity in man. this study compares the cross-reactivity between the chironomid midge cladotanytarsus lewisi ('green nimitti'), a widespread cause of allergy in the sudan and chironomus riparius (= thummi, ctt) where larvae are used as pet fish food and where haemoglobins were previously shown to be major allergens. as with c. riparius, immature forms of c. lewisi also contain allergenic material since skin test responses t ... | 1985 | 2411447 |
| effects of ph on the toxicity and uptake of [14c]lindane in the midge, chironomus riparius. | the toxicity of the insecticide, lindane, was measured in the midge, chironomus riparius, at ph 4, 6, and 8 with the finding that lindane is significantly more toxic at ph 6 than at ph 4 and 8. the higher toxicity of lindane at ph 6 is a product of two factors. first the penetration of the compound into the midge is lower at ph 4 than at ph 6 and 8. second, a greater percentage of total radioactivity is contributed by parent compound at ph 6. | 1985 | 2417806 |
| effects of temperature on the acute toxicity of pcp in the midge chironomus riparius meigen. | | 1986 | 3708179 |
| accumulation of mercury in larvae and adults, chironomus riparius (meigen). | | 1986 | 3742100 |
| effect of cadmium on oviposition and egg viability in chironomus riparius (diptera: chironomidae). | | 1987 | 3814856 |
| effects of ph on the acute toxicity and uptake of [14c]pentachlorophenol in the midge, chironomus riparius. | the acute toxicity of pentachlorophenol (pcp) was determined at ph levels 4, 6, 9 to the midge, chironomus riparius, with the findings that pcp is of greatest toxicity at ph 4 and of least toxicity at ph 9. this differential toxicity is attributable to variations in uptake levels at the respective ph levels. at ph 4, pcp is fully protonated and therefore highly lipophilic. the amount of [14c]pcp present in the midges at 24 hr is thus highest at ph 4. conversely, at ph 9, the compound is complete ... | 1986 | 3956426 |
| the development of haemoglobins in chironomus riparius (meig.) (diptera: chironomidae). | | 1970 | 5448825 |
| the distribution of the midge chironomus riparius in a polluted river system and its environs. | | 1966 | 5917584 |
| organization of the cuticle of an aquatic fly larva. | the aquatic, apneustic larva of the midge, chironomus riparius, has a very thin (up to 5 micrometers), readily deformable, post-cephalic cuticle. the ultrastructure of this cuticle from newly moulted and older final instar animals, and exuvia shed at pupation, has been examined using routine methods and also after the extraction of proteins with formamide and acetic acid. from the results described, and using established criteria, it is inferred that an exocuticle is present and represents about ... | 1983 | 6612713 |
| kinetics and biotransformation of benzo(a)pyrene in chironomus riparius. | uptake and depuration kinetics for benzo(a)pyrene (b(a)p) were determined for the midge chironomus riparius (diptera) with one and two compartment models. nonfeeding animals were exposed to nominal 1.0 microgram.l-1 14c- b(a)p for eight hr. depuration over eight hr was determined in animals with and without substrate. the uptake rate constant was 214 +/- 20 hr-1 (x +/- se, n = 3), while elimination rate constants for the first four hr were 0.22 hr-1 (with substrate) and 0.06 hr-1 (without substr ... | 1982 | 7073316 |
| effects of 3,4-dichloroaniline on the growth of two freshwater macroinvertebrates in a stream mesocosm. | the growth of the freshwater macroinvertebrates gammarus pulex (l.) and chironomus riparius meigen exposed to 3,4-dichloroaniline in chambers within stream mesocosms was determined. dca significantly affected the growth of neonate g. pulex and third instar c. riparius over 25 and 12 days, respectively. the no-observed-effect concentrations (noecs) obtained in the tests were 0.08 mg dca liter-1 (g. pulex) and 0.76 mg dca liter-1 (c. riparius) and these are compared to toxicity data from other inv ... | 1994 | 7529166 |
| tolerance induction and life cycle changes in cadmium-exposed chironomus riparius (diptera) during consecutive generations. | cultures of chironomus riparius were exposed to cadmium during nine consecutive generations to determine whether cadmium tolerance could be induced. selection for cadmium tolerance was assumed to influence the population dynamics of this species. therefore, the responses and interactions of different population parameters (such as mortality, growth, and reproduction) were studied during the selection process. exposure to cadmium during consecutive generations caused increasing effects on some li ... | 1995 | 7539374 |
| chronic toxicity of cadmium to chironomus riparius (diptera: chironomidae) at different food levels. | the interacting effects of cadmium toxicity and food limitation on the midge, chironomus riparius, were studied during chronic exposure in laboratory experiments. if the food was supplied ad libitum, both larval developmental time and mortality of the larvae were negatively affected by cadmium concentrations of 2.0-16.2 micrograms/l. the number of eggs deposited per female and the mean life span of the imagines were not affected by cadmium. integration of these separate effects into a population ... | 1994 | 8311506 |
| tolerance of chironomus riparius larvae (diptera: chironomidae) to salinity. | | 1996 | 8791561 |
| characterization of lake ladoga sediments. i. toxicity to chironomus riparius and daphnia magna. | toxicity of surficial sediment of lake ladoga, russia, was studied using bioassays with a midge, chironomus riparius and daphnia magna. many lake ladoga sediments caused high mortality of midge larvae in 10-d growth and 40-d emergence tests. in most sediments the biomass production of chironomids was also lowered. however, no statistically significant effect on timing of emergence was observed. sediment elutriate or pore water tests did not exhibit toxicity to daphnia magna. the adverse effects ... | 1996 | 8920594 |
| uptake and metabolism of benzo(a)pyrene absorbed to sediment by the freshwater invertebrate species chironomus riparius and sphaerium corneum. | | 1997 | 8952940 |
| effect of temperature on cadmium and zinc uptake by the midge larvae chironomus riparius. | the effect of temperature (5 to 25 degrees c) was studied on the uptake of cadmium and zinc by larvae of the midge chironomus riparius, using artificial chemically defined solutions. the influence of prior acclimation of midge larvae at five temperatures on metal uptake was examined. at all acclimation temperatures metal uptake in organisms increased with increasing exposure temperature. among the different temperature exposure groups the effect of temperature acclimation on metal uptake is rath ... | 1996 | 8975823 |
| environmental health assessment of the benthic habitat adjacent to a pulp mill discharge. i. acute and chronic toxicity of sediments to benthic macroinvertebrates. | in this study, we assessed the acute and chronic toxicity of sediments contaminated by bleached kraft pulp mill effluent (bkme). sediments were collected in august 1991 and 1992, and may 1993 from eight stations exposed directly to the effluent and from four reference sites.acute toxicity was determined for five macroinvertebrates (hyalella azteca, daphnia magna, chironomus riparius, hexagenia spp., and tubifex tubifex) using pore water, elutriate, and bulk sediment exposures. chronic toxicity w ... | 1997 | 9096076 |
| recovery following pulsed exposure to organophosphorus and carbamate insecticides in the midge, chironomus riparius. | the importance of recovery following pulsed and continuous exposure was determined by measuring the acute toxicity of two organophosphorus (parathion and malathion) and four carbamate (aldicarb, carbaryl, carbofuran and propoxur) insecticides. two 1-h pulses caused significantly fewer symptoms of intoxication than 2 h of continuous exposure if at least 2 to 6 h in clean water were provided between doses for the four carbamates. two 1-h pulses were equally toxic as a single 2-h continuous exposur ... | 1997 | 9216867 |
| ecotoxicological hazard assessment of two polymers of distinctively different molecular weights. | assessment of ecological risks during manufacturing, use, transport, and disposal are becoming increasingly important as planning tools during development of new products. the objective of this study was to establish the potential ecotoxicological hazard associated with two polycarboxylate polymers in water, sludge, sediment, and soil. the concentrations of both polymers were quantified using 14c-radiolabeled synthesis and liquid scintillation counting (lsc). the program included water column ac ... | 1998 | 9469856 |
| effects of organophosphorus, carbamate, pyrethroid and organochlorine pesticides, and a heavy metal on survival and cholinesterase activity of chironomus riparius meigen. | | 1998 | 9528704 |
| bioassays using the midge chironomus riparius and the zebra mussel dreissena polymorpha for evaluation of river water quality. | to evaluate if the water quality of the river meuse affects macrofauna species, the impact of water from this river on two representative species was tested under controlled conditions. short-term bioassays with reference populations of the midge chironomus riparius and the zebra mussel dreissena polymorpha were performed simultaneously, using growth and filtration rate as sublethal parameters, respectively. filtration rates of mussels seemed to be slightly inhibited by meuse water in 1994 and 1 ... | 1998 | 9543505 |
| c band variation in polytene chromosomes of chironomus riparius (diptera, chironomidae) from a polluted piedmont station (italy). | c banding in polytene chromosomes of chironomus riparius from a santena polluted station of the river po, italy was described. a large variation in the appearance of c bands was established. the process involved the transformation of euchromatin into heterochromatin. activation of all chromosomes at telomeres was found. a structural modification of telomeric heterochromatin may exist. the centromeric heterochromatin was rarely observed. a high percentage of an amplification (88%) in arm f, b3h, ... | 1997 | 9547063 |
| experimental induction of morphological deformities in chironomus riparius larvae by chronic exposure to copper and lead | five consecutive generations of chironomus riparius meigen larvae were chronically exposed from egg to fourth instar to four sublethal concentrations of copper (0, 1, 10, 100 µg l-1) and lead (0, 5, 50, 500 µg l-1) in artificially spiked water (static with renewal), with diatomaceous earth as substrate and tetraphyl(r) as food, in order to test the induction of morphological deformities by these metals. the use of diatomaceous earth was suboptimal because it caused high mortalities (>60%), indep ... | 1998 | 9680517 |
| the toxicity of margosan-o, a product of neem seeds, to selected target and nontarget aquatic invertebrates | margosan-o, an insecticide formulated from extracts of neem tree (azadirachta indica) seed kernels, besides being toxic, also has feeding, oviposition-deterring, and growth-inhibitory effects on insects. this product, registered in the united states for ornamental plants, has been proposed for food crop use. however, little information exists on its effects on aquatic organisms. this study investigated toxicity of margosan-o to the mosquito culex spp., a possible target species, and to nontarget ... | 1998 | 9732473 |
| feeding activity of midge larvae (chironomus riparius meigen) in metal-polluted river sediments. | a method was developed for monitoring the feeding activity of larvae of the midge chironomus riparius. the egestion rate (mg dry wt feces/mg dry wt larva/h) of the deposit-feeding larvae was measured and used as an indication of the feeding activity. both the egestion rate and survival of several metal-adapted and reference larvae were measured in five test sediments with various cd and zn concentrations. the reference larvae suffered increased mortality in two contaminated sediments by comparis ... | 1998 | 9799576 |
| altered cholinesterase and monooxygenase levels in daphnia magna and chironomus riparius exposed to environmental pollutants. | biochemical indices were investigated for their potential use as variables of sublethal toxicity in daphnia (cholinesterase) and chironomus (cholinesterase and biotransformation enzymes). parathion, dichlorvos, and aldicarb caused dose-related inhibition of cholinesterase (che) in 24-h bioassays with both species. ratios of daphnia and chironomus che ic50 values to corresponding immotility ec50 values derived from the same experiment covered the range 0.26 to 1.2. estimates of the che inhibition ... | 1999 | 9931232 |
| detection of a p-glycoprotein related pump in chironomus larvae and its inhibition by verapamil and cyclosporin a. | a membrane associated atp-dependent efflux pump, similar in function to mammalian p-glycoprotein, was detected in anal papillae of chironomus riparius larvae. immunohistochemical analysis of larval tissues, using monoclonal antibodies against p-glycoprotein, was supplemented by functional in vivo and in vitro assays which confirmed the existence of a mechanism for transporting xenobiotic substances. the in vitro atpase activity of homogenate fractions increased in the presence of typical p-glyco ... | 1998 | 9972316 |
| formation and identification of azaarene transformation products from aquatic invertebrate and algal metabolism. | the metabolism of two azaarenes, viz. acridine and phenanthridine, by aquatic organisms was studied in short-term and chronic laboratory tests. the identity of metabolites observed in the test waters was investigated with different analytical methods, including hplc, gc and hyphenated lc- or gc-ms. the zebra mussel (dreissena polymorpha), one green alga species (selenastrum capricornutum) and periphyton or bacteria transformed acridine into 9[10h]-acridinone. phenanthridine was transformed into ... | 1999 | 10219667 |
| body residues and responses of the midge chironomus riparius to sediment-associated 2,4,5-trichlorophenol in subchronic and chronic exposures | subchronic and chronic toxicity of sediment-associated 2,4, 5-trichlorophenol to the midge chironomus riparius was determined by conducting a 10-day growth and a 50-day emergence tests with spiked lake sediment (nominal initial tcp concentrations were 25, 51, 101, 203, 304 and 405 &mgr;mol kg-1 dry weight in the growth test and 25, 76, 152 and 304 &mgr;mol kg-1 dry weight the emergence test). in addition, we measured the residue of chlorophenol in larval tissue and made an attempt to relate it w ... | 1999 | 10341041 |
| fluctuating life-history parameters indicating temporal variability in metal adaptation in riverine chironomids | adaptation to toxicants in animal populations is influenced primarily by two counteracting forces. first, the intensity and duration of peak concentrations of toxicants is responsible for the actual level of selection pressure on the population. second, the process of adaptation can be disrupted by gene flow as a result of crossings with nontolerant individuals. these counteracting forces were analyzed in riverine insects in which we expected that the level of metal adaptation is subject of cons ... | 1999 | 10398767 |
| characterization of superoxide dismutase activity in chironomus riparius mg. (diptera, chironomidae) larvae--a potential biomarker. | the activities of superoxide dismutase (sod) isoenzymes were measured in fourth instar larvae of chironomus riparius mg. three types of superoxide dismutase were identified: cu,zn-sod in hemolymph and postmitochondrial fraction; mn-sod in mitochondrial fraction and presumably fe-sod in postmitochondrial fraction. the latter could have an endosymbiotic or a parasitic origin. extracellular and cytosolic sod activities, especially cu,zn-sod, tended to increase in the last phase of larval developmen ... | 1999 | 10579651 |
| new artificial sediment for chironomus riparius toxicity testing. | | 1999 | 10594141 |
| development of methods for evaluating toxicity to freshwater ecosystems. | this article presents a summary of a collaborative research program involving five european research groups, that was partly funded by the european commission under its environmental research program. the objective of the program was to develop aquatic toxicity tests that could be used to obtain data for inclusion at level 2 of the risk evaluation scheme for the notification of substances as required by the 7th amendment to ec directive 79/831/eec. currently only a very limited number of test me ... | 2000 | 10648133 |
| identification of a putative ribosomal protein mrna in chironomus riparius and its response to cadmium, heat shock, and actinomycin d. | a putative ribosomal protein (rp) mrna in chironomus riparius has been found using differential display (dd). its sequence has 84.8% identity with mosquito rp l8, aedes albopictus, and is approximately 0.9 kb. studies were undertaken in order to evaluate rp as a control for environmentally relevant genes. responses of drosophila heat shock 70 gene (hsp70) were used to establish heat shock temperatures and cadmium (cd) concentrations for chironomus experiments and to validate dd. expression of hs ... | 2000 | 10789497 |
| effects of ph on cadmium and zinc uptake by the midge larvae chironomus riparius. | we studied the effect of ph on the uptake of cadmium and zinc by fourth instar larvae of the midge chironomus riparius within the ph range 5.5-10.0, using chemically defined solutions. the effect of prior acclimation on metal uptake was examined for four ph levels, i.e. ph 5.5, 7.0, 8.0 and 9.5. at least three factors were important in determining the effect of ph on the cadmium and zinc uptake by midge larvae. the effect of ph on metal uptake is the combined result of changes in free metal ion ... | 2000 | 10814813 |
| interacting effects of toxicants and organic matter on the midge chironomus riparius in polluted river water. | toxicants and organic matter in river water have contrasting impacts on macrofauna. through manipulations of both factors, their interactive effects on organisms were evaluated. this way, an attempt was made to clarify the presence or absence of pollution-"tolerant" and -"sensitive" species in rivers affected by mixed sources of pollution. under controlled conditions, larval growth of the "tolerant" midge chironomus riparius was measured in different types of river water containing varying level ... | 2000 | 10903833 |
| a comparative study of chironomus riparius meigen and chironomus tentans fabricius (diptera:chironomidae) in aquatic toxicity tests. | chironomus riparius meigen and chironomus tentans fabricius were examined under controlled conditions and exposed to the reference toxicants cadmium and lindane (gamma-hexachlorocyclohexane) to identify any differences that could have implications for their use in aquatic toxicity testing. preliminary studies showed that both species could be cultured in the laboratory using similar methodology, resulting in the typical bimodal emergence of adult males prior to females. however, adults of c. rip ... | 2000 | 10948279 |
| the toxicity of a neem insecticide to populations of culicidae and other aquatic invertebrates as assessed in in situ microcosms. | microcosm trials were conducted with the botanical insecticide margosan-o(r) to assess the potential hazards of the product to aquatic organisms. laboratory chronic bioassays with water from the treated microcosms were conducted to provide an estimate of the residual effect of margosan-o. results from chronic tests showed margosan-o toxicity to be greater in the laboratory exposures than in situ with culicidae larvae exposed to the same concentrations. residue analyses of the active ingredient, ... | 2000 | 10948283 |
| phenyl- and butyltin analysis in small biological samples by cold methanolic digestion and gc/ms. | a very efficient technique for the analysis of six butyl- and phenyltin compounds in biota samples has been developed. no special equipment is needed for sample preparation, which is based on cold methanolic digestion with subsequent aqueous ethylation and liquid-liquid extraction. for samples of only 40 mg of biological materials, method detection limits ranging from 4 to 52 ng/g were achieved using gas chromatography/mass spectrometry. relative recoveries for the individual butyl- and phenylti ... | 2000 | 11055739 |
| exposure of chironomus riparius larvae (diptera) to lead, mercury and beta-sitosterol: effects on mouthpart deformation and moulting. | mouthpart deformation in chironomid larvae is induced by exposure to chemical contaminants and is becoming an established bio-indicator in sediment assessment programmes. however, concentration-response relationships with causal agents have only been established occasionally and with varying success. in this laboratory study, instar ii and iii larvae were exposed to sub-lethal concentrations of lead, mercury and beta-sitosterol. a significant deformation response was induced in the pecten with l ... | 2000 | 11057685 |
| influence of uv radiation on four freshwater invertebrates. | laboratory tests confirmed a negative and variable response of the following four species to artificial uv radiation: cypridopsis vidua, an ostracode; chironomus riparius, a midge larvae; hyalella azteca, an amphipod; and daphnia magna, a daphnid. severe damage occurred at uv-b irradiance ranging from 50 to 80% of incident summer values. under constant exposure to uv and photosynthetically active radiation (par) the acute lethal response was recorded at 0.3, 0.8, 0.8 and 4.9 w m-2 uv-b for d. ma ... | 2000 | 11107851 |
| effect of environmental pollution on the chromosomal variability of chironomus riparius meigen 1804 (diptera, chironomidae) larvae from two piedmont stations. | different frequencies of chromosomal alterations in salivary gland polytene chromosomes ab, cd and ef were described in larvae of chironomus riparius (syn. chironomus thummi) from the trace metal-polluted station of santena on the river banna, near turin, and from the unpolluted station of corio (40 km from turin) which was taken as a reference area. in a sample of 56 larvae from santena, no specimen with the standard karyotype in all cells of the salivary glands was found. different types of ab ... | 2000 | 11138945 |
| the use of chironomid deformation in an in situ test for sediment toxicity. | an in situ bioassay using mouthpart deformities in chironomus riparius larvae was developed to monitor sediment toxicity. second-instar larvae, along with a standardized amount of food and sediment taken from the study locations, were enclosed in cages that were placed on the sediment surface of rivers. mouthpart deformities were screened after larval molting to the fourth instar (exposure time: 7-10 days). mouthpart deformities of caged and field larvae (when present) were related to the estima ... | 2000 | 11139175 |
| comparative metabolism of phenanthridine by carp (cyprinus carpio) and midge larvae (chironomus riparius). | abiotic transformation of azaarenes in the environment has been analysed extensively, but metabolism is less well described. to further elucidate preliminary observations of interspecific differences in azaarene metabolism by aquatic organisms, phenanthridine biotransformation by midge larvae and carp was studied. in both experiments, 6(5h)-phenanthridinone (phenanthridone) was found as an important metabolite. the fish were clearly capable of metabolising phenanthridine, but in the midge experi ... | 2001 | 11202649 |
| induction of mouthpart deformities in chironomus riparius larvae exposed to 4-n-nonylphenol. | chironomid mouthpart deformities have often been associated with sediment contamination and are, therefore, currently used to assess sediment quality. deformities were only occasionally induced in laboratory bioassays. mouthpart deformities results from a physiological disturbance during larval molting. in the past few years it has been shown that some chemicals can exert negative effects on both vertebrates and invertebrates at the level of endocrine regulation. as insect molting is hormonally ... | 2001 | 11202727 |
| identifying body residues of hcbp associated with 10-d mortality and partial life cycle effects in the midge, chironomus riparius. | the relationship between the body residue of 2,2',4,4',5,5'-hexachlorobiphenyl (hcbp) and its effects, including 10-d mortality and chronic sublethal effects on the midge, chironomus riparius, are examined in a partial life cycle assessment. the alga, chlorella vulgaris, was loaded with 14c-labeled hcbp and fed to midges as the method for delivery of the toxicant. in a 10-d bioassay, median lethal body residue (lr50) was 0.57 (95% ci: 0.49-0.66) mmol/kg. in the partial life cycle test, midges we ... | 2001 | 11239686 |
| exposure of chironomus riparius larvae to 17alpha-ethynylestradiol: effects on survival and mouthpart deformities. | evidence from field studies shows that mouthpart deformities in chironomid larvae are a sublethal response to pollution. interest has been shown to use this end-point in programs for monitoring sediment quality. during laboratory studies, however, deformities were induced in only a few single pollutant exposures. these deformities develop at the endocrine regulated molting stage and disruption of this complex process is likely at the base of their ontogeny. aiming to clarify the processes involv ... | 2001 | 11305336 |
| effects of the hormone mimetic insecticide tebufenozide on chironomus riparius larvae in two different exposure setups. | the effects of the molting-hormone agonistic insecticide tebufenozide on larvae of the midge chironomus riparius meigen were tested in two different exposure setups. after static contamination of first-instar larvae the noec, loec, and lc50 values were 13.2, 17.4, and 21.14 microg/l, respectively. semistatic exposure of fourth-instar larvae revealed a lower susceptibility of elder larvae (noec 30 microg/l, loec 60 microg/l, and lc50 81.94 microg/l). in both cases mortality was not immediate; the ... | 2001 | 11386731 |
| fate and effects of esfenvalerate in agricultural ponds. | the fate of esfenvalerate was investigated by sampling and chemical analysis after spraying of an artificial pond (25 g a.i./ha) and in the laboratory with [14c]esfenvalerate by trapping of 14co2 and fractionation of the sediment. the effects were investigated on pelagic communities in enclosures in a natural lake and in the laboratory on surface (cymatia coleoptrata) and sediment (chironomus riparius) insects. the latter were used in sediment-plus-water and in water-only tests, measuring effect ... | 2001 | 11434300 |
| comparison of acetylcholinesterase and glutathione s-transferase activity in chironomus riparius meigen exposed to chemical-spiked sediments. | | 2001 | 11443330 |
| toxicity of freshwater sediments in the vicinity of an old sawmill: application of three bioassays. | toxicity of contaminated sediments collected from an old sawmill area and the downstream river-lake system was assessed with three different bioassays. survival and growth were used as endpoints in subchronic (10-day) test with chironomus riparius and growth and reproduction in long-term (28-day) test with lumbriculus variegatus. a microbial bioluminescent direct contact assay, the flash test, was also included in the test set to measure acute toxicity. in every bioassay, sediment from a pool of ... | 2001 | 11443361 |
| short-term exposure to sub-lethal doses of lindane affects developmental parameters in chironomus riparius meigen, but has no effect on larval glutathione-s-transferase activity. | chironomus riparius meigen were exposed to 0, 0.01, 0.1, 0.5, 0.75 and 1.0 ppm lindane for 48 h as fourth instar larvae. exposure had no effect on glutathione-s-transferase (gst) activity in larvae snap-frozen immediately following exposure. in contrast, exposure had longer-term consequences affecting developmental parameters. concentrations above 0.5 ppm lindane affected larval behaviour, reduced adult body size and fecundity and delayed emergence times. the lack of significant change in gst ac ... | 2001 | 11482645 |
| the relationship of chironomus riparius larval se body burden and body concentration to larval dry mass and effects on sensitivity to selenium. | selenium as selenite was added to laboratory cultures of chironomus riparius. in two sets of cultures, substrate-bound se concentrations were typically 10(3) times dissolved se concentrations, while in the other set dissolved se concentrations were about 10 to 50 times substrate-bound se concentrations. body burdens of individual second-, third-, and fourth-instar larvae and eviscerated fourth-instar larvae were measured. regressions of se body burden on larval dry mass found evidence for separa ... | 2001 | 11491543 |
| variability in acetylcholinesterase and glutathione s-transferase activities in chironomus riparius meigen deployed in situ at uncontaminated field sites. | an in situ system was used to expose fourth instar chironomus riparius meigen larvae for 48-h at 13 uncontaminated river sites across southeast england. acetylcholinesterase (ache) and glutathione s-transferase (gst) activities were measured in individual larvae recovered from these sites. activities of both biomarkers varied almost twofold across the sites, with statistically significant differences detectable between sites. there were no clear relationships between biomarker activities and phy ... | 2001 | 11491555 |
| life-cycle effects of sediment-associated 2,4,5-trichlorophenol on two groups of the midge chironomus riparius with different exposure histories. | effects of 2,4,5-trichlorophenol (tcp) on life-cycle traits of the midge chironomus riparius and the ability of the midge to evolve tolerance to tcp were assessed using a reference group and a group preexposed to tcp during three generations, both originating from the same laboratory culture. f1 larvae of these groups were then exposed to nominal tcp concentrations of 51, 177, 355, and 532 micromol tcp/kg dry sediment and a control sediment in a life-cycle experiment. most studied life-cycle tra ... | 2001 | 11491561 |
| effect of short-term exposure to chlorpyrifos on developmental parameters and biochemical biomarkers in chironomus riparius meigen. | chironomus riparius meigen were exposed to sediment spiked with 0, 0.01, 0.05, and 0.10 mg chlorpyrifos/kg dry sediment for 48 h as late third-instar larvae. acetylcholinesterase activity, glutathione-s-transferase activity, burrowing behavior, emergence time, and adult dry weight were measured to determine which were the most sensitive biomarkers of exposure and effect for short-term sublethal exposures. there was a significant drop in acetylcholinesterase activity at the two highest concentrat ... | 2001 | 11534949 |
| hypoxia, hyperoxia and exposure to potassium dichromate or fenitrothion alter the energy metabolism in chironomus riparius mg. (diptera: chironomidae) larvae. | short-term (24 h) effects of four stressors (hypoxia, hyperoxia, potassium dichromate, fenitrothion) on the activity of the electron transport system (ets) and total lipid, glycogen and protein contents were assessed in 4th instar larvae of chironomus riparius. hypoxia and hyperoxia caused an increase in ets activity and protein content. glycogen content decreased when larvae were placed under hypoxic conditions. ets activity increased following exposure to 2 microg x l(-1) of fenitrothion. it d ... | 2001 | 11544139 |
| chronic exposure to 17 alpha-ethinylestradiol and bisphenol a-effects on development and reproduction in the freshwater invertebrate chironomus riparius (diptera: chironomidae). | the effect of 17 alpha-ethinylestradiol (ee) and bisphenol a (bpa) on development and reproduction in chironomus riparius was determined over two generations in chronic sediment exposure assays. a number of response criteria were examined in order to identify any chemical-related effects including median emergence times (emt50), the number and sex ratio of emerged adults, egg production and egg viability. the results showed that emergence time and percentage adult emergence were affected by ee a ... | 2001 | 11551626 |
| leucine transport in membrane vesicles from chironomus riparius larvae displays a mélange of crown-group features. | leucine uptake into membrane vesicles from larvae of the midge chironomus riparius was studied. the membrane preparation was highly enriched in typical brush border membrane enzymes and depleted of other membrane contaminants. in the absence of cations, there was a stereospecific uptake of l-leucine, which exhibited saturation kinetics. parameters were determined both at neutral (km 33 +/- 5 microm and vmax 22.6 +/- 6.8 pmol/7s/mg protein) and alkaline (km 46 +/- 5 microm and vmax 15.5 +/- 2.5 p ... | 2001 | 11568964 |
| the use of sediment analogues to study the uptake of pollutants by chironomid larvae. | a technique is described that uses artificial resin beads with known surface properties to investigate the factors influencing the bioaccumulation of pollutants from sediments. one advantage of this technique is that it provides a standard procedure against which it is possible to calibrate natural sediments with their diverse properties. the method has been used on third instar larvae of the midge chironomus riparius and the results are compared with previous studies on the worm lumbriculus var ... | 2001 | 11586776 |
| single and combined effects of sediment-associated pahs on three species of freshwater macroinvertebrates. | polycyclic aromatic hydrocarbons (pahs) are ubiquitous pollutants of sediments. sediment quality criteria often use toxicity data for individual pahs. however, pahs always occur in field sediments as a complex mixture of compounds. in this study, the toxicity of phenanthrene (p), fluoranthene (fla) and benzo(k)-fluoranthene (b), alone or in combination, was assessed using monospecific sediment tests of acute toxicity (between 24 h and 14 days). the test sediments were spiked formulated sediments ... | 2001 | 11759569 |
| evaluation of bioassays versus contaminant concentrations in explaining the macroinvertebrate community structure in the rhine-meuse delta, the netherlands. | it is often assumed that bioassays are better descriptors of sediment toxicity than toxicant concentrations and that ecological factors are more important than toxicants in structuring macroinvertebrate communities. in the period 1992 to 1995, data were collected in the enclosed rhine-meuse delta, the netherlands, on macroinvertebrates, sediment toxicity, sediment contaminant concentrations, and ecological factors. the effect of various groups of pollutants (polycyclic aromatic hydrocarbons, tra ... | 2001 | 11764175 |
| toxicity of 4-nonylphenol in spiked sediment to three populations of chironomus riparius. | nonylphenols (nps) are the primary stable metabolites of alkylphenol polyethoxylates (apes), a family of compounds widely used in industry and in some domestic products. as nps accumulate in sediments in aquatic environments, the risk to benthic organisms needs to be assessed. in this study 4np-spiked sediments were tested on larvae of the dipteran chironomus riparius. first instar larvae obtained from populations at three different sources were used. to spike the sediments, an equilibration pro ... | 2002 | 11827276 |
| biomimetic solid-phase microextraction to predict body residues and toxicity of chemicals that act by narcosis. | a biomimetic extraction technique using solid-phase microextraction (spme) fibers has been developed for the risk assessment of contaminants with a narcotic mode of action. our goal is to apply this technique in the future for the prediction of total baseline toxicity of environmental water and effluent samples. validation of this method requires establishing the relationship between contaminant accumulation and toxicity in biota and accumulation in the surrogate solid phase (the spme fiber coat ... | 2002 | 11837229 |
| dynamics of metal adaptation in riverine chironomids. | the ability of the non-biting midge chironomus riparius to survive and reproduce in metal polluted lowland rivers facilitates the opportunity to study micro-evolutionary processes in situ. however, due to larval drift, adapted midge populations are subject to regular immigration of non-adapted specimens from clean upstream river reaches. to examine the influence of non-adapted genes in adapted midge populations on the level of metal adaptation, an upstream and downstream chironomid population we ... | 2002 | 11858165 |
| evidence of differences in the biotransformation of organic contaminants in three species of freshwater invertebrates. | acute static bioassays were performed using three freshwater invertebrate species (the oligochaete lumbriculus variegatus, the fingernail clam sphaerium corneum and the larvae chironomus riparius) exposed separately to a variety of 14c radiolabelled contaminants. the aim of this work was to investigate if the chemicals remained as parent compounds after the treatments. chemicals used were 2,4-dichlorophenol; 2,4,5-trichlorophenol; pentachlorophenol; pyrene; fenpropidin, and trifluralin. homogena ... | 2002 | 11926182 |
| mouthpart deformities and nucleolus activity in field-collected chironomus riparius larvae. | chironomid mouthpart deformities and aberrations of their polytenic chromosomes are sublethal responses to toxic stress. these endpoints have been used in several cases as bioindications for sediment pollution. in the present study we aimed to establish whether there was an association between mouthpart deformities and nucleolus activity in the polytenic chromosomes. such information could be useful to gain insight into the mechanisms involved in the occurrence of mouthpart deformities and their ... | 2002 | 11994780 |
| ecdysteroid synthesis and imaginal disc development in the midge chironomus riparius as biomarkers for endocrine effects of tributyltin. | acute effects of the endocrine disruptor bis(tri-n-butyltin) oxide (tbto) on molting-hormone biosynthesis and imaginal-disc development were investigated in larvae of the midge chironomus riparius (meigen). ecdysteroid synthesis was measured by 24-h incubation of molting-hormone-synthesizing tissues (prothoracic glands) in vitro with or without the addition of tbto. the amount of ecdysteroids produced was analyzed by radioimmunoassay. developmental effects in vivo were investigated by determinin ... | 2002 | 12013127 |
| effect of temperature and pirimiphos methyl on biochemical biomarkers in chironomus riparius meigen. | fourth-instar chironomus riparius meigen larvae were exposed to the organophosphate (op) insecticide pirimiphos methyl (0, 0.1, 1.0, and 10 microg/l) for 48, 72, or 96 h at three temperatures (3, 12, or 22 degrees c). two biochemical biomarkers, acetylcholinesterase (ache) and glutathione s-transferase (gst), were measured in individual larvae from each treatment. ache activity was inhibited by the op in a dose-responsive fashion. this response remained similar at all three temperatures, demonst ... | 2002 | 12061829 |
| lethal body residue of chlorophenols and mixtures of chlorophenols in benthic organisms. | the lethal body residue (lbr) of a few chlorophenol congeners were measured in the oligochaete worm lumbriculus variegatus, and the lbr of pentachlorophenol was measured also in a midge, chironomus riparius larvae. lbr is defined as the concentration of the compound in the organism, on molar basis, to cause death, and the lbr(50) is defined as the calculated lbr value to cause a 50% mortality in population after a given time. groups of 30 or 40 organisms were exposed to different chlorophenol co ... | 2002 | 12115047 |
| comparative toxic and genotoxic effects of chloroacetanilides, formamidines and their degradation products on vibrio fischeri and chironomus riparius. | toxic and genotoxic effects of alachlor, metolachlor, amitraz, chlordimeform, their respective environmentally stable degradation products 2,6-diethylaniline, 2-ethyl-4-methylaniline, 2,4-dimethylaniline, and two other related compounds, 3,4-dichloroaniline and aniline were compared. acute toxicity tests with chironomus riparius (96 h) and vibrio fischeri (microtox) and genotoxicity tests with a dark mutant of v. fischeri (mutato) were carried out. our results demonstrate that toxicity and genot ... | 2002 | 12152826 |
| cadmium-induced production of a metallothioneinlike protein in tubifex tubifex (oligochaeta) and chironomus riparius (diptera): correlation with reproduction and growth. | laboratory-cultured chironomus riparius and tubifex tubifex were exposed to sediments artificially enriched with a range of cadmium (cd) concentrations. both species accumulated cd in a concentration-dependent manner. the concentration of a metallothioneinlike protein (mtlp), as measured by a mercury saturation assay, increased with increasing cd exposure. after reaching a threshold of cd exposure, the whole-body endpoints of reproductive output in t. tubifex and growth in c. riparius declined s ... | 2002 | 12206423 |
| advancing monosaccharides as biomarkers: part i. development of fluorophore-assisted carbohydrate-electrophoresis in chironomus riparius. | fluorophore-assisted carbohydrate-electrophoresis (face) was developed as a bioassay for environmental stressors in larval chironomus riparius. this quantitative technique involved acid hydrolysis and 2-aminoacridone labeling of monosaccharides followed by carbohydrate gel electrophoresis. methods for carbohydrate isolation from whole tissue homogenates as well as migration distances for 23 different monosaccharides and 4 disaccharides were established. sensitivity of the technique (5 microg/ml ... | 2002 | 12297374 |
| advancing monosaccharides as biomarkers: part ii. effects of starvation and cadmium in chironomus riparius as detected by fluorophore-assisted carbohydrate-electrophoresis. | saccharides were evaluated as biomarkers for cadmium (cd) and starvation using fluorophore-assisted carbohydrate-electrophoresis (face) in 4th instar chironomus riparius. face allowed different types of saccharides in whole larval homogenate to be analyzed simultaneously and in parallel with other larval samples. larval homogenates showed seven principle bands labeled a, b, c, d, e, f and g. previous work found that the migration patterns of bands a, c, d and f matched those of ribose, glucose, ... | 2002 | 12297375 |
| responses of benthic invertebrates to combined toxicant and food input in floodplain lake sediments. | benthic communities in floodplain lake ecosystems are often exposed to varying levels of both food and toxicants. inhibition through toxicants of sensitive species and stimulation through increased amounts of food of opportunistic species have been observed in separate studies. the aim of this study was therefore to assess the responses of benthic invertebrates to combined food and contamination input. hence, seven floodplain lakes located along the river waal, the netherlands, with different le ... | 2002 | 12371493 |
| a modeling approach to link food availability, growth, emergence, and reproduction for the midge chironomus riparius. | we present models to link feeding with growth, emergence, and reproduction of the midge chironomus riparius. these models are based on assumptions about the biology of this species and distinguish between males and females. the assumptions are the isomorphism of the chironomidae, the fact that much more energy is used for growth than for maintenance, and the existence of a maximum length for male and female larvae that does not depend on food availability. we supported our assumptions by experim ... | 2002 | 12389933 |
| nonrandom chromosomal distribution of spontaneous breakpoints and satellite dna clusters in two geographically distant populations of chironomus riparius (diptera: chironomidae). | two geographically distant populations of chimnomus riparius (syn. c. thummi) from two environmentally polluted sites (santena, italy and varna, bulgaria) show numerous somatic and inherited chromosomal aberrations (inversions, deletions and deficiencies). fifty-five percent of the observed breakpoints occurred in at least two larvae from both populations. breakpoints occurring twice or more were considered as 'common' structural chromosomal breakpoints. we tested whether such common breakpoints ... | 2002 | 12440567 |
| environmental chemicals with known endocrine potential affect yolk protein content in the aquatic insect chironomus riparius. | the use of vitellogenesis as a marker for possible effects of endocrine disrupting agents on insects was tested in the aquatic midge chironomus riparius. as test substances the synthetic ecdysoid tebufenozide, and the endocrine disruptors bisphenol a and 4-n-nonylphenol were applied in a semi-static manner. the yolk protein contents of freshly emerged (24 h) male and female midges were determined by an elisa procedure. in males, where always low amounts of immunoreactivity were apparent, yolk co ... | 2002 | 12442778 |
| multilevel effects of sublethal fenitrothion exposure in chironomus riparius mg. (diptera, chironomidae) larvae. | the effects of fenitrothion exposure on fourth-instar chimnomus riparius larvae were investigated on biochemical, physiological, and population-level parameters. biochemical effects were investigated through measurements of acetylcholinesterase and cytosolic superoxide dismutase activities. water content and dry weight of the larvae were used as physiological parameters, and the emergence rate of adults was used as a descriptor of population-level effects. results showed that the response of mos ... | 2002 | 12463571 |
| toxicity of 4-nonylphenol to tubifex tubifex and chironomus riparius in 28-day whole-sediment tests. | concern has been growing recently over the toxicity and the mimicking properties of 4-nonylphenol (4np), the most persistent breakdown product of the nonionic surfactant nonylphenol ethoxylates, broadly used in industrial cleaning processes. twenty-eight-day tests were performed to evaluate the toxicity and the effects on reproduction of 4np spiked sediment to the benthic invertebrates tubifex tubifex and chironomus riparius. 4np was directly added to the wet sediment, avoiding any solvent. the ... | 2002 | 12481866 |
| relationship between biomarker activity and developmental endpoints in chironomus riparius meigen exposed to an organophosphate insecticide. | the biomarkers acetylcholinesterase (ache) and glutathione s-transferase (gst) were measured in fourth-instar chironomus riparius meigen larvae exposed to the organophosphate insecticide pirimiphos methyl (0, 5, 10, and 50ng/g) for 48 or 96h, and at high or low food ration. larvae exposed to 50ng/g pirimiphos methyl died within 48h. the weight of larvae exposed to 10ng/g pirimiphos methyl was significantly lower than those exposed to 0 and 5ng/g. ache activity was significantly reduced in larvae ... | 2002 | 12485579 |
| the fate, distribution, and toxicity of lindane in tests with chironomus riparius: effects of bioturbation and sediment organic matter content. | in this laboratory study, we address the effect of chironomus bioturbation (0, 2,000, 6,000, and 18,000 ind/m2) and sediment organic matter content (10, 20, and 40%) on the fate, distribution, and bioavailability of 14c-lindane under standardized conditions in toxicity tests with artificial sediment. the results show that both chironomus burrowing activity and sediment organic matter strongly modify test conditions. larval mortality and development were inversely related with chironomus densitie ... | 2003 | 12503748 |
| statistical analysis of sediment toxicity by additive monotone regression splines. | modeling nonlinearity and thresholds in dose-effect relations is a major challenge, particularly in noisy data sets. here we show the utility of nonlinear regression with additive monotone regression splines. these splines lead almost automatically to the estimation of thresholds. we applied this novel method to explore the relation between the toxicity of aquatic sediments, as observed in bioassays with daphnia magna, chironomus riparius and vibrio fischeri, and the degree of contamination of t ... | 2002 | 12521140 |
| bioconcentration of organic chemicals: is a solid-phase microextraction fiber a good surrogate for biota? | when organic chemicals are extracted from a water sample with solid-phase microextraction (spme) fibers, the resulting concentrations in exposed fibers are proportional to the hydrophobicity of the compounds. this fiber accumulation is analogous to the bioconcentration of chemicals observed in aquatic organisms. the objective of this study was to investigate the prospect of measuring the total concentration in spme fibers to estimate the total body residue in biota for the purpose of risk assess ... | 2002 | 12521167 |
| assessing sediment toxicity and arsenite concentration with bacterial and traditional methods. | three sediment samples lp (pool where logs are stored), lf (brook through landfill area), kn (kaskesniemi) which is in lake pyhäselkä downstream from the mill, were taken from an old sawmill area and one from the unpolluted lake höytiäinen. the arsenite concentration was measured by gfaas and two arsenite biosensing bacterial strains pseudomonas fluorescens os8 (ptpt31) and escherichia coli mc1061 (ptoo31). the toxicity of sediment and pore water samples was determined by using luminescent bacte ... | 2003 | 12547530 |
| induction of cytochrome p-450 activity in individual chironomus riparius meigen larvae exposed to xenobiotics. | cytochrome p450 activity in individual chironomus riparius larvae was measured using a microtiter plate adaptation of the ethoxyresorufin-o-deethylase (erod) assay. the sensitivity of this biomarker was tested by exposing larvae to phenobarbital (0.5 and 1.0 mm) and permethrin (1 and 10 microg/g). both chemicals induced erod activity in c. riparius larvae by up to 1.58-fold with pb and 2.47-fold with permethrin. erod induction was more pronounced after 48 h. the initially high erod activity in t ... | 2003 | 12547628 |
| exposure to 17 alpha-ethinylestradiol and bisphenol a--effects on larval moulting and mouthpart structure of chironomus riparius. | the effects of the endocrine-disrupting chemicals 17alpha-ethinylestradiol (ee) and bisphenol a (bpa) on the development of the aquatic life-cycle stages (eggs to pupa) of chironomus riparius were investigated. the test species was exposed to sublethal concentrations of ee and bpa (10 ng/l-1mg/l) and effects on larval weight and moulting success were recorded. in addition, three mouthpart structures (mentum, mandibles, and pecten epipharyngis) present on the head capsules of fourth-instar larvae ... | 2003 | 12550099 |
| assessing the toxicity of dodecylbenzene sulfonate to the midge chironomus riparius using body residues as the dose metric. | dodecylbenzene sulfonate (dbs) is a component of linear alkylbenzene sulfonate (las), an anionic surfactant, mainly used in household detergents. due to the large quantity of dbs in use, there is concern over adverse environmental effects. this work examined the toxicokinetics and toxicity of the 2-phenyl isomer of dodecylbenzene sulfonate in 4-d, 10-d, and partial life-cycle tests on the midge, chironomus riparius, exposed to aqueous solutions. toxicokinetics were determined in 10-d uptake and ... | 2003 | 12558161 |
| functional and structural rearrangements of salivary gland polytene chromosomes of chironomus riparius mg. (diptera,chironomidae) in response to freshly neutralized aluminium. | although recent work has shown that environmentally relevant concentrations of freshly neutralized aluminium (ai) are bioavailable and toxic to freshwater invertebrates, the genotoxicity of al has not been examined. here we show that freshly neutralized al affects structure and function of the salivary gland polytene chromosomes of the ubiquitous chironomid larva chironomus riparius over three generations. exposure to 500 microg l-1 added al for 24-25 days resulted in a significantly higher freq ... | 2003 | 12628199 |
| identification of endocrine-disrupting effects in aquatic vertebrates and invertebrates: report from the european idea project. | the eu-funded project idea aimed to evaluate (a) what parameters and endpoints allow the detection of endocrine-mediated developmental and reproductive effects of (xeno)estrogens in life cycle- and life stage-specific toxicity tests with the zebrafish danio rerio, a small laboratory fish used in many ecotoxicity test guidelines, and (b) whether substances that act as estrogens in vertebrates may also adversely affect the development, differentiation, and reproduction of aquatic invertebrates. th ... | 2003 | 12651186 |
| the relative sensitivity of four benthic invertebrates to metals in spiked-sediment exposures and application to contaminated field sediment. | the relative sensitivity of four benthic invertebrates (hyalella azteca, chironomus riparius, hexagenia spp., and tubifex tubifex) was determined for cd, cu, and ni in water-only and in spiked-sediment exposures. survival (median lethal concentrations [lc50s] and the concentrations estimated to be lethal to 25% of test organisms [lc25s]), and endpoints for growth and reproduction (mean inhibitory concentrations [ic25s]) were compared. the sensitivities differed depending on the species and metal ... | 2003 | 12685721 |
| responses in sediment bioassays used in the netherlands: can observed toxicity be explained by routinely monitored priority pollutants? | in order to identify the cause of toxicity in sediments and suspended matter, a large number of samples with different degrees of contamination was taken at various locations in the netherlands. standard acute bioassays were carried out with the bacterium vibrio fischeri, the rotifer brachionus calyciflorus and the anostracan thamnocephalus platyurus. chronic standard tests were performed using the water flea daphnia magna and larvae of the midge chironomus riparius. some novel bioassays were pe ... | 2003 | 12697214 |