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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

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

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.

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

Measurements/observations

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.

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

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: 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

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

Measurements/observations

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.

[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.

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.

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

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

Evaluations

[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).

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.

Measurements/observations

Arsenic concentrations in worm.