Lumbriculus variegatus
Lumbriculus variegatus (Muller) is the sediment dwelling oligochaete. L. variegatus is native to European and North American river and lake sediments, known to be moderate sensitive to xenobiotics. It feeds on micro-organisms and decomposing plant material. (ref. ID; 6707)
L. variegatu is a freshwater oligochaete that has been widely recommended and used as a standard bioindicator organism for toxicity tests to evaluate both water and sediment quality (American Society for Testing Materials [ASTM] 2010; United States Environmental Protection Agency [USEPA] 2000) (ref. ID; 7169)
[ref. ID; 1323]
Test system
Assimilation efficiencies
Toxicants
Lake Michigan sediments (approximately 8 km southwest from Grand Haven, MI (43.03 degrees N, 86.37 degrees W) at 45-m depth) + [3H]-benzo(a)pyrene (BaP), [14C]-2,2',4,4',5,5'-hexachlorobiphenyl (HCBP), [14C]-polydimethylsiloxane (PDMS).
Temperature
23+/-2 degrees C.
[ref. ID; 2166]
Test system
7-days toxicity assay & bioaccumulation assay
Test design
Lake Michigan sediments (about 8 km southwest of Grand Haven, Michigan (43 degrees 02.2'N, 86 degrees 21.9'W), 45 m depth) + pyrene (0.4 ng/g and 64, 132, 206, and 269 ug/g). Temperature 23+/-1 degrees C.
Measurements/observations
Pyrene concentration, body weight.
Evaluations
EC50 by probit analyses.
[ref. ID; 2169]
Test system
Bioaccumulation assay
Toxicants
[14C]polydimethylsiloxane, [H3]benzo(a)pyrene.
Test design
Lake Michigan sediments (approximately 8 km southwest from Grand Haven, Michigan, at 45-m depth) + Benzo[a]pyrene (about 190 pg/g) + PDMS (0, 50 and 150 ug/g).
[ref. ID; 2171]
Test system
10-day Flow-through toxicity test (effect of pH)
Strains
From in-house cultures, were mixed-age adults.
Toxicants
Total ammonia, un-ionized (NH3) ammonia.
Temperature
25 degrees C.
Test design
Lake Superior water (pH 7.8, hardness and alkalinity ca. 40 mg/L as CaCO3).
pH: 6.3, 7.2, 7.8, and 8.6.
Evaluations
LC50.
[ref. ID; 2172]
Test system
Effect of ultraviolet (UV) radiation (photoactivation of PAHs)
Strains
From cultures maintained in Lake Superior water (LSW) at the EPA-Duluth laboratory.
Toxicants
Sediments contaminated with polycyclic aromatic hydrocarbons (PAHs: Acenaphthalene, Anthracene, Chrysene, Fluoranthene, Fluorene, Naphthalene, Phenanthrene, Pyrene, Benzo[e]pyrene, Benzo[a]pyrene).
Test design
In situ exposure & laboratory exposure. Photoperiod 16L:8D UV-light.
Measurements/observations
Mortality.
Evaluations
Mann-Whitney U test (using SYSTAT statistical software).
[ref. ID; 4445]
Test system
48-hr Lethal Body Residue (LBR) assay
Strains
In the Aquatic Ecology and Ecotoxicology Laboratory at the University of Joensuu.
Toxicants
Chlorophenols (2,6-dichlorophenol, 2,4,5-trichlorophenol, pentachlorophenol; 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol).
Test design
Artificial freshwater: CaCl2/2H2O 58.8 mg/l, MgSO4/7H2O 24.7 mg/l, KCl 1.1 mg/l, NaCO3 13.0 mg/l (total Ca + Mg hardness 1.0 mmol/l), pH 6.5. Temperature 20+/-1 degrees C.
Measurements/observations
Mortality, body residue (umol/g wet weight organisms).
Evaluations
LC50 & LBR50.
[ref. ID; 4446]
Test system
28-day gamma scan assay
Strains
From the U.S. Environmental Protection Agency (U.S. EPA), Midcontinent Ecology Division (Duluth, MN).
Toxicants
Fluoranthene
Test design
Sediment (from the Little Scioto River (OH) at a site (40 degrees 35.55'N by 83 degrees 10.98'W) with very low concentrations PAHs (3.9 ug/g) + [14C]Fluoranthene concentration (0, 50, 100, 200, and 300 ug/g dry sediment).
Measurements/observations
Bioaccumulation rate, number, reworking rate.
[ref. ID; 4475]
Test system
Bioconcentration and 120-hr acute toxicity
Strains
Toxicants
Galaxolide, Tonalide.
Test design
- Bioconcentration factor: 4 individuals were exposed in 10-L aquaria to 9 L of solution in a flow-through system to maintain a constant nominal aqueous concentration of 12 ug/L.
- Acute toxicity: 10 worms were exposed in triplicate in 1.5-L bottles filled with 1 L of test solution in CFW (copper-free Utrecht tap water).
Measurements/observations
Mortality, cytochrome P450, isoenzyme activity.
Evaluations
BCFs, EC50.
[ref. ID; 4477]
Test system
Toxicokinetics (7 days and 1.5 years)
Strains
Adult.
Toxicants
Benzo[a]pyrene, hexachlorobiphenyl.
Test design
250-ml beakers (25 g spiked sediment + 200 ml overlying water), 16L:8D photoperiod. Temperature 20 degrees C.
Evaluations
Bioaccumulation factor (BAF).
[ref. ID; 4478]
Test system
Biota-sediments accumulation factors (BSAFs)
Strains
Mixed-age.
Toxicants
DDT and its metabolites (DDD, DDE), PAHs.
Test design
4-L glass beaker (1 L of whole sediments + 3 L of overlying well water), 16L:8D photoperiod at about 200 lux. Temperature 23 degrees C.
- Sediment contaminated with DDT and its metabolites was collected from Huntsville Spring Branch near Huntsville (AL, USA).
- Sediment contaminated with PAHs was collected from the Little Scioto River near Dayton (OH, USA).
- Control sediment was collected from the Pequaywan Lake (Mn, USA).
Measurements/observations
Wet weight, lipid content, concentration (PAHs, OCs, and PCBs) in L. variegatus.
[ref. ID; 4480]
Test system
Bioaccumulation test
Strains
Toxicants
Cadmium chloride, Copper chloride, Lead nitrate, Zinc chloride.
Temperature/light conditions
23+/-1 degrees C, 16L:8D photoperiod.
Test design/concentrations
300-ml-high form beaker: sediment 100-ml [uncontaminated natural sediment (West Bearskin Lake (Cook County, MN, USA; 48 degrees 3.86'N, 90 degrees 24.61'W)) + Cd (8 umol/g dry weight), Pb (8 umol/g dry weight), Cu (12.5 umol/g dry weight) and Zn (12 umol/g dry weight)] + dechlorinated Lake Superior tap water 170 ml (hardness 47 mg/L as CaCO3, alkalinity 49 mg/L as CaCO3), food (Aquatox flake fish food).
Measurements/observations
Metal concentration in L. variegatus.
[ref. ID; 6000]
Test system
Lethal and sublethal (behavioral test and electrophysiological test) test
Strains
Toxicants
Ivermectin (11.5 mM in 40% glycerol formal and 60% propylene glycol), picrotoxin (Cl- channel blocker).
Temperature
22+/-1 degrees C.
Test design
- Lethal test: Exposure was carried out in cover glass petri dishes (9 cm in diameter, 2 cm in depth) with one worm per container of 50 ml solution. Each level was replicated 10 to 21 times. Five concentration (180, 320, 560, 1000 and 1,800 nM), 10 worms per concentration, 24 and 72 hr exposure duration. Very high concentration (2,400 nM), 10 worms, 8 hr exposure duration.
- Behavioral test:
[Helical swimming and body reversal behaviors] Exposure was carried out in cover glass petri dishes (9 cm in diameter, 2 cm in depth) with one worm per container of 100 ml solution. Each level was replicated 10 to 21 times. Concentration levels (solvent (propylene glycol), 0.3, 3, 30, and 300 nM). In each test, a worm was touched 10 times with rubber probe alternately at its anterior or posterior end to evoke reversal and swimming, respectively. The interval between successive touches was 3 to 5sec.
[Swimming frequency and pattern] A worm was placed in the middle of a plastic petri dish) 14 cm in diameter, 2.5 cm in depth) containing 200 ml of distilled water. Swimming responses were evoked twice by tactile stimulation to the posterior end of the worm using a rubber probe. The worm was allowed to rest about 2 min after it was moved into the dish and between the two trials. Concentration levels (0, 0.03, 0.3, 3, and 30 nM).
[Crawling] In the crawling test, a worm was placed next to a smooth strip of Plexiglas (180x40x6 mm) that rested on a piece of thoroughly wetted filter paper (Whatman No.1, Bangkok, Thailand). A straight rubber band (5 mm long, 0.5 mm in diameter, attached to a wooden applicator stick) was used to brush the worm's tail so that the worm would crawl forward in a straight line along the Plexiglas. The frequency of brushing was 3.6+/-0.1 strokes/sec (n=20). This stimulation lasted 10 to 15 s, or until the worm had crawled 4 to 6 cm. Concentration level (0, 10, 30, 100, and 300 nM).
- Electrophysiological test: A worm was placed next to a smooth strip of Plexiglas (4x1 cm) on printed circuit board recording grid moistened with distilled water. The worms' medial and lateral giant fiber (MGF and LGF) systems were activated by tactile stimulation to the anterior and posterior ends of the worms, respectively.
Measurements/observations
- Lethal test: Mortality.
- Behavioral test: Swimming frequency, swimming ability, reversal ability, crawling speed, crawling frequency and escape reflex.
Evaluations
LC50, IC50.
[ref. ID; 6013]
Test system
The impact of sediment manuplication on bioaccumulation test
Sediment sampling sites
From the Little Scioto River in north-central Ohio, USA. Its location downstream from an abandoned railroad yard suspected to be a source of creosote contamination. Eckman grab samples of surficial sediment (0-5 cm) were homogenized and press-sieved gently by hand through a 1-mm screen to remove indigenous animals and large debris.
Toxicants
PAHs (Flourene, Phenanthrene, Anthracene, Flouranthene, Pyrene, Benzo[a]anthracene, Chrysene, Benzo[b]flouranthene, Benzo[e]pyrene, Benzo[a]pyrene, perylene, Indeno[1,2,3-cd]pyrene, Benzo[glu]perylene)
Test design
Sediment + [3H]pyrene and [14C]benzo[a]pyrene + animals, 3 replicates.
- Assay 1: Minimally mixed.
- Assay 2: Slurry mixed, aged 10 days.
- Assay 3: Slurry mixed, aged 42 days.
Measurements
Radionuclide analysis (PAHs concentration of body burden (ng/g, wet wt)).
[ref. ID; 6015]
Test system
Acute toxicity (96 hr LC50 and EC50), the effect on simple lotic food web (72-days)
Strains
From Bio-International (NJ Horn, The Netherlands).
Toxicants
Terbutryn
Temperature/light
15+/-1 degrees C, the daily sun rhythm.
Test design
- Acute toxicity: Using 24-well multiplates, terbutryn concentration 0, 14.5, 17.3, 20.8, 25.0, and 30 mg/L.
- Food web: The five artificial indoor streams were made of stainless steel (V2A-steel) and were set up in a greenhouse. The stream bed was divided lengthwise by a steel plate into two channels (A and B). Washed gravel from a gravel pit (size [% of overall composition]: 16-32 mm [18%], 8-16 mm [47%], and 2-8 mm [35%]), which contained neither clay nor organics, was used as sediment and distributed uniformly in each channels of the artificial stream. The streams were filled with approximately 500 L of tap water up to a water level of 100 mm in the stream bed. The water was circulated at 0.2 m/sec. Aufwuchs (primarily periphytic algae). Terbutryn concentration 0.6, 6, 60, 600 ug/L.
Measurements/observations
Dry weight of aufwuchs, number of segments and dry weight of worm.
Endpoints
Acute toxicity: Lethal (lysis, lack of blood circulation, and protrusion of coelomic fluid), sublethal (deformation and autotomy).
Evaluations
96 hr LC50 and EC50.
[ref. ID; 6705]
Test system
Effect of dissolved oxygen concentration on freshwater sediment toxicity tests
Strains
From in-house cultures, mixed age, 2-4 cm.
Test design
10 individuals/test beaker (working water volume about 250 ml, continuous flow system 25-30 ml min-1). Exposure period 10 days. 22.9+/-1 degrees C. 16:8 light:dark photoperiod from ambient fluorescent lighting.
Measurements/observations
Survival number.
Evaluations
EC50, EC20, EC10 by nonlinear regression analysis using TRAP Version 1.02 (USEPA, 2006).
[ref. ID; 6707]
Test system
Biomonitoring
Strains
NOAA/Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan, USA.
Toxicants
Atrazine
Test design
Sampling site:
- Spree River, a former industrial area directly bordering the river, known to have high amounts of residues of hexachlorcyclohexane (lindane), polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDT) in the soil, as well as sediment-bound heavy metal contamination especially zinc, lead and cadmium.
- Teltow Canal, a focal point of high contamination load with PAH's and several classes of chlorinated, brominated and mixed halogenated compounds and some of their metabolites in the sediments as well as charges in the free water column and particle bound compounds.
- New Wuhle, receiving sewage output until 2003.
- Old Wuhle, a semi-natural small river with possible marring influence from garden plots where the uncontrolled use of pesticides in common.
Water toxicity tests: The worm were exposed for 4 hr, 1, 3 and 7 days to 0.05, 0.5 and 5 mg l-1 atrazine dissolved in Dimethylsulfoxide (DMSO). Four replicates of 40 worms in 100 ml for each concentration and the control (0.01% DMSO).
Sediment toxicity test: Sediments were engraved with an Ekman-Birge bottom sampler three times at each sampling site (0-10 cm upper layer). Forty worms per replicate were exposed to 10 g of sediment from each sampling site for 1, 4 and 7 days. Artificial tank water (30 ml) was added.
Measurements/observations
- Enzyme activities.
- CAT (oxidative defense enzyme catalase) activity.
- Solbule and membrane bound GST (gultathione-S-transferase: sGST and mGST).
- Protein content.
Evaluations
One-way analysis of variance (ANOVA) followed by Duncan's Test, using p <0.05, 0.01 or 0.001.
[ref. ID; 6721]
Test system
Bioaccumulation
Strains
From the Great Lakes Environmental Research Laboratory (Ann arbor, MI, USA).
Toxicants
3,3',4,4'-Tetrachlorobiphenyl (PCB 77).
Test design
A 50-ml glass beaker with 30 g of wet spiked sediment (Lake Kuorinka and Lake Hoytiainen). Aerated artifical freshwater was added on top of the sediment to avoid sediment disturbance. Five midsize (5-7 mg), adult worms were placed in each beaker (triplicate). At room temperature (20+/-1 degrees C) with a 16:8-hr light:dark photoperiod under yellow fluorescent light (>500 nm).
Measurements/observations
PCB concentration in tissue of worm, lipid content.
[ref. ID; 6751]
Test system
Bioaccumulation and effects on biotransformation and antioxidant enzymes
Strains
NOAA/Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan, USA.
Toxicant/concentrations
Glyphosate, Rundup Ultra (0, 0.05, 0.1, 0.5, 2 and 5 mg L-1).
Test design
- Bioaccumulation: 500 mL glass bottles (266 ml [14]C-radiolabelled glyphosate medium + 40 worms), ground fish food 15 mg/day. 3 replicates. Exposure periods 4 days at 20 degrees C.
- Physiological response: Glass dish (100 ml glyphosate medium + 15 worms), ground fish food 5 mg/day. 4 replicates. Exposure periods 4 days at 20 degrees C.
Measurements/observations
- Bioaccumulation: Glyphosate and AMPA concentrations in the medium and worm body.
- Physiological response: Protein content and enzyme activity (glutathione S-transferase (soluble GST, membrane bound GST), catalase (CAT), and superoxide dismutase (SOD)) of the worm tissue.
Evaluations
Bioaccumulation: BCF.
One-way analysis of variance (ANOVA) followed by Duncan's Test, using p <0.05, 0.01 or 0.001.
[ref. ID; 6825]
Test system
Bioaccumulation
Strains
From in-house culture.
Toxicants
Radiolabelled synthetic steroid 17alpha-ethinylestradiol ([14]C-EE2).
Test design
Artificial sediment (75% fine quartz sand (average grain size 0.17 mm), 20% kaolinite clay and 4.5% sphagnum peat powder) + 0.5% fine powder of stinging nettle Urtica sp. water content approx. 46%. pH 7.0.
Lid-covered glass aquarium, which contained the test vessels, was installed in a climate chamber and kept at 20+/-2 degrees C. Each test vessel (100 ml glass tubes) for the uptake and elimination phase of the experiment was filled with 26 g wt spiked sediment and 60 ml reconstituted water as overlying medium, resulting in a sediment to water ratio of 1:4 (v/v). 10 warm per test vessel. Light intensity 100-300 lux at a 16:8 hr light-dark cycle. Exposure period 35 days. After 35 days, the elimination phase of the experiment was started by transferring the worms of the remaining 20 test vessels from spiked into uncontaminated sediment. Elimination period 10 days.
Measurements/observations
[14]C-EE2 concentrations in worm tissues.
[ref. ID; 6829]
Test system
Bioavailability
Strains
Toxicants
Pyrene.
Test design
Thirty glass jars (60 ml) were prepared by adding either 10 feeding (intact adult worms (5-10 mg wet weight/individual) with fully formed posterior and anterior ends) or non-feeding (worms removing the head end of the worm (2-4 mm) with a scalpel) worms to each jar. Aged spiked sediment (20+/-2 g) was added to each vessel covering the worms, followed by 30+/-1 ml of groudwater (NO2<1 mg/l, NO3<5 mg/l, NH4<1 mg/l, NH3<1 mg/l, Cl<10 mg/l, Ca=110 mg/l. Mg<20 mg/l, CaCO3=230 mg/l, pH=7.8). The vessels were then fitted to an aeration system and kept 20+/-2 degrees C. Experimental period 220 days.
Preparation of spiked sediment: Uncontaminated surface sediment was removed to a depth of 20 cm with a spade from a gravel pit at the ARC Study Centre, Milton Keynes, UK. Wet sediment (5+/-0.1 kg) was spiked with [14]C-pyrene dissolved in a methanol carrier.
Measurements/observations
Radioactivity.
[ref. ID; 6853]
Test system
Test methods (culturing procedure and test protocols) to assess the acute and chronic toxicity and the presence of bioaccumulatable compounds in contaminated sediments
Strains
Test design
For bulk sediment tests at the Environmental Research Laboratory-(ERL-)Duluth. Sediments: Contaminated sediments (Torch Lake, Keweenaw Waterway) and non-contaminated sediment (West Bearskin Lake).
Measurements/observations
Number of worms and total biomass.
[ref. ID; 6929]
Test system
Bioaccumulation
Strains
From a local aquatic pet supply store. 2 to 3 cm in length worm used.
Toxicant/concentrations
Triclocarban (TCC) 22.4 ppm.
Test design
Sediment: Pristine lake sediment obtained from Agvise Laboratories with nondetectable levels of TCC was utilized.
150-ml glass beaker was filled with ~40 g dry weight sediment. The beakers were held in a temperature-controlled waterbath (23+/-2 degrees C) on a 16:8 light:dark photoperiod.
The overlying water (synthetic freshwater) was maintained at approximately 2 cm to ensure adequate dissolved oxygen levels, at a rate of approximately 20 ml every other day. Triplicate beakers were prepared and terminated at each time point, which were days 0, 1, 3, 7, 10, 14, 21, 28, 35, 42, 49, and 56 for the uptake experiment and days 35 (Down day 0), 36, 38, 40, 42, 45, 49, and 56 for the elimination experiment.
Measurements/observations
Worm tissue concentration of TCC and 4,4'-Dichlorocarbanalide (DCC: potential transformation product of TCC).
Evaluations
Biota-sediment-accumulation factors (BSAFs).
[ref. ID; 6937]
Test system
Bioaccumulation
Strains
Native oligochaetes were collected from 23 navigational pools along the UMR and from the Saint Croix River.
Toxicants
Sediment in the upper Mississippi River (UMR) arose after the flood of 1993.
Test design
Laboratory testing: L. variegatus were exposed in 28-day sediment exposures following methods described in US EPA (1994) and ASTM (1998). Exposures of oligochaetes were conducted in 4-L glass Pyrex beakers containing 1 L of sediment and 3 L of overlying water. Four replicate chambers were tested for each of the 13 sediment samples. Beakers were held in a temperature-controlled waterbath (23+/-1 degrees C) on a 16:8 light:dark photoperiod at about 500 lux. Oligochaetes were no fed during the sediment exposure. Beakers received two volume additions (6 L +/- 10%) of overlying water per day.
Measurements/observations
Worm tissue concentration of PAHs (naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl, 2,6-dimethylnaphthalene, fluorene, 1,6,7-trimethylnaphthalene, phenanthrene, 1-methylphenanthrene, pyrene, fluoranthene, chrysene, benzo(a)anthracene, benzo(b,k)fluoranthene, perylene, benzo(e)pyrene).
Evaluations
Biota-sediment-accumulation factors (BSAFs).
[ref. ID; 6962]
Test system
Bioaccumulation routes
Strains
Toxicants
Radiolabeled pyrene-4,5,9,10-[14]C.
Test design
Architomic reproduction mode of L. variegatus induces worms of sufficient size to fragment into two parts approximately from the middle of the body. After fragmentaion, new individuals regenerates fresh segments for tail (former anterior end) and head/prostomium (former posterior end). During this process, worms do not ingest sediment, and this pause has been observed to last approximately 6-7 days with posterior end in lake Hortianen sediment. It is also quite common that the posterior part divides further, resulting in the pause in feeding to prolong 10-12 days with the new posterior part. Lumbriculus feeds in subsurface sediment and egests all ingested material on the sediment surface, which allows simultaneously both the quantification egestion rate and detection of onset of ingestion. These feature in reproduction and feeding behavior were used as a basis for experimental design.
Sediment: Pump-collected, fine-grained sediment from lake Hoytiainen (an unpolluted, oligotrophic lake in Eastern Finland).
A 50 ml beaker with 20 ml of spiked or control sediment containing one worm was used as an experimental unit.
- Group 1: The smallest worms (5-9 mg wet weight).
- Group 2: Large worms (12-21 mg wet weight) were selected and placed individually into beakers with clean, unspiked Lake Hoytianinen sediment. After 2 days, most of the worms had divided and the posterior ends were selected for the bioaccumulation test.
- Group 3: Worms were born during the accumulation test from group 2 posterior worms by architomy 5-7 days after the beginning of the exposure.
[ref. ID; 7021]
Test system
Review
Toxicants
Sediment-associated contaminants.
[ref. ID; 7028]
Test system
Bioaccumulation and Biotransformation
Strains
Toxicants/concentrations
Four [14]C-polychlorinated alkanes (PCAs): C12H20Cl6 [56% Cl by weight] 26.5 and 106 ng/g sediment dry weight, C12H16Cl10 [69% Cl] 124 and 442 ng/g, C16H31Cl3 [35% Cl] 47.1 and 135 ng/g, C16H21C13 [69% Cl] 264 ng/g.
Test design
Sediment were collected from Lake 468, an oligotrophic, nncontaminated lake at the Experimental Lakes Area (ELA), Ontario, Canada. For spiking, the sediment was added to a 6-L flask that contained ~5 L of distilled water, and the sediment-water slurry was mixed with a Teflon stir bar and mixer. [14]C-dichlorinated alkanes were added to the slurry in ~100 ul of acetone, and the sediment was mixed for 24 hr. After mixing, the sediment was allowed to settle and the water was decanted leaving 1 cm of overlying water.
60-ml glass jars were filled with sufficient sediment to provide a 100:1 organic carbon to lipid ratio for 15 oligochaetes (~100 mg). No food. Temperature 11.6+/-0.1 degrees C.
- Uptake phase: Sampling time 1, 3, 7, 10 and 14 day.
- Depuration phase: Sampling time 1, 3, 7, 10, 14, 28, and 42 day.
Measurements/observations
Lipid percentages (wet weight) of oligochaeta. [14]C in oligochaeta, sediment, and interstitial water.
Evaluations
BSAFs.
[ref. ID; 7029]
Test system
Influence of sediment purging period for bioaccumulation data
Strains
Toxicants
Test design
Approximately 600 adult oligochaetes (>3-cm length) were added to a 19-cm-diameter crystallizing dish containing 750 ml of sediment (a moisture content of 79%, 7.4% TOC, and particle size dominated by silt/sand (50.5% sand, 47.2% silt, 2.3% clay)) from West Bearskin Lake (Cook Country, MN, USA) (free of toxicologically significant contamination) with an overlying layer of 1.5L Lake Superior water. About 0.25 g of trout chow was added for food source. Temperature 23+/-1 degrees C. After 48 hr, Oligochaetes were sieve and placed in a shallow tray containing Lake Superior water, and then measured weight. 28 groups of 10 worms were placed in separate, 300-ml-high form beakers, which were subsequently placed in an intermittent water renewal system receiving Lake Superior water. Groups of four beakers were removed for weight analysis at 1, 2, 4, 6, 8, 12, and 24 hr after initial sieving. Automatic water renewal occurred during hours 2 and 14 of this purging period.
Measurements/observations
Total dry weight and ash weight.
[ref. ID; 7125]
Test system
Relationship between reproduction, sediment type, and feeding activity
Strains
From National Oceanic and Atmospheric Administration (NOAA)/Great Lakes Environmental Research Laboratory (Ann Arbor, MI, USA).
Test design
Sediment type: Sediments from Lake Hoytianen and Lake Mekrijarvi from eastern Finland. Both sediments are from unpolluted fine-grained depositional areas.
- Test I: Eighteen replicate beakers (volume 25 ml) were filled with test sediment (15 ml), quartz sand (a layer a few millimeters thick above the sediment), and artificial freshwater (17 ml, according to Suomen Standardisoimisliito except that pH was adjusted to 6.5 and hardness was increased to 10 mmol/L (Ca + Mg)). A single oligochaete (4-17 mg wet weight, dry matter content 10%) in each beaker. Light and temperature condition were 16 hr light:8 hr dark cycle at 20+/-2 degrees C. Exeprimental period 28 days.
- Test II: Ten animals, each >13 mg wet weight, were placed individually in beakers. Oligochaetes reproduced by dividing into two parts within 2 to 4 days. The newborn oligochaete fragments were sieved out and placed individually in new analogous beakers. After transfer, the egestion rate was recorded daily during the first 8 days and every 2nd or 3rd day thereafter until the 30th day. If reproduction was observed during the test, new oligochaete fragments were sieved out again, placed individually in new beakers, and the development of feeding was followed.
Measurements/observations
The egestion rate (= feeding activity, mg dry feces/mg dry worm/hr) of oligochaetes was followed by collecting fecal pellets on the quartz sand by pipette. Lipid content of dried oligochaetes. Worm weight.
[ref. ID; 7131]
Test system
Acute (96-hr) and chronic (28-days) toxicity
Strains
Adults were obtained from Aquatic Research Organisms.
Toxicants
Chloride
Test design
- Acute toxicity: American Society for Testing Material (1997).
- Chronic toxicity: U.S. EPA (2000).
Tests were conducted using four replicates per concentration in glass jar containing 100 ml of sediment (clean, a beach-collected sand) and filled to 275 ml with the test solutions. Food (digested yeast) were added. The exposure were conducted at 2 +/-1 degrees C with a 16:8 hr lgiht:dark photoperiod. Five worms per replicates.
Measurements/observations
- Acute toxicity: Mortality.
- Chronic toxicity: Biomass.
Evaluations
- Acute toxicity: LC50.
- Chronic toxicity: IC25, IC50.
[ref. ID; 7136]
Test system
Acute toxicity
Strains
Adults were obtained from laboratory culture at the U.S. Geological Survey Columbia Environmental Reseach Center (Columbia, MO).
Toxicants
Silicon carbide nanowires (SiCNW).
Test design
Water-only test: 30 mg of sonicated SiCNW was added to four replicates 50-ml glass beakers containing 30 ml test water (ASTM reconstituted hard water, hardness 160-180 mg/L as CaCO3, alkalinity 110-120 mg/L as CaCO3). Ten organisms were added. The exposure were conducted at 23 degrees C in a temperature-controlled water bath under a photoperiod of 16:8 hr light:dark with a intensity of about 200 lux. Exposure period 4 days. No food.
Measurements/observations
Survival.
[ref. ID; 7138]
Test system
Pyrene biotransformation
Strains
From the Great Lakes Environmental Reseach Laboratory (Ann Arbor, MI, USA). The worms to be used were removed from culture and kept in clean water to empty their guts for 24 hr before experiment.
Toxicants
Pyrene and radiolabeled pyrene.
Test design
Inhibition of cytochrome P450 (CYP) isozyme activity of piperonyl butoxide (PBO).
- Experiment 1: Water exposure treatment.
Pyrene (nominal concentration = 10 ug/L).
Pyrene (10 ug/L) + PBO (35.4 ug/L).
Pyrene (10 ug/L + PBO (354 ug/L).
Radiolabeled pyrene was additionally added to all the treatments to a nominal concentration of 0.15 ug/L.
The 400-ml beakers were filled with 350 experimental water, and 12 worms (~60 mg). All the experiments were carried out under yellow light (wave-length >500 nm), to avoid photodegradation of the pyrene.
Sampling time were 8, 24, 48, 72, 96, and 168 hr. Four replicates.
- Experiment 2: The nominal concentration of pyrene was 20 ug/L, and neither PBO nor ladiolabeled pyrene were present.
1-L beaker with 900 ml artificial water and approximately 400 mg worms without purging their gut. Sampling time was 168 hr. Constant aeration.
L. variegatus (~200 mg wet wt) were exposed to a nominal concentration of pyrene of 20 ug/L in water for approximately two months.
Measurements/observations
Pyrene and Pyrene derivatives in worm tissue.
[ref. ID; 7169]
Test system
Bioavailability and bioaccumulation
Strains
From Prof. Simkiss (Ecotoxicology Research Group, School of Animal and Microbial Sciences, University of Reading, Readng, UK). Adult (2.5+/-0.5 cm length).
Toxicants
As2O3
Test design
48 hr under static conditions at a temperature of 21+/-2 degrees C. No food.
- Uptake test: 10 organisms were placed in 25-ml scintillation glass containing 20 ml varying arsenic concentrations (0.0-5.0 mg As L-1). Triplicates.
- Elimination test: 5 sets of 10 worms each were exposed to 0.4 mg As L-1 for 48 hr. After the treatment, 1 set was immediately processed for metalloid analysis (t=0), whereas the other 4 sets were transferred to clean water for t=4, 6, 24, and 48 hr before arsenic determination. 3 replicates.
- Influence of HAs (commercial humic acids) on arsenic bioaccumulation: 10 organisms were exposed to aqueous solutions containing 0, 5, 20, or 60 mg HA L-1 plus 0.4 mg As L-1 for 48 hr.
- Uptake of arsenic from the particles: 10 worms were placed in glass vials containing 20 mL 0.4 mg As L-1 and 2 g solid phase. The solid phase consisted of either 2 g sand particles or 0.5 g each resin (Dowex 1 x 8400, an anionic exchanger; Toyopearl SP-650 M, a cationic exchanger; Toyopearl Butyl 650 M, a neutral material; Toyopearl Phenyl 650 M, neutral material) plus 1.5 g sand.
Measurements/observations
Arsenic concentrations in worm.