Sublethal responses to endrin in sediment by Limnodrilus hoffmeisteri (Tubificidae), and in mixed-culture with Stylodrilus heringianus (Lumbriculidae)

Abstract

Sediment reworking by Limnodrilus hoffmeisteri (Tubificidae) alone, and with Stylodrilus heringianus (Lumbriculidae) were measured in sediments dosed with endrin by monitoring the burial of a 137cesium marker layer. Endrin concentrations ranged from 16.1 to 81 400 ng/g dry sediment weight. Alterations in reworking rates were observed at sediment concentrations two to five orders Of magnitude below LCso values. In single species experiments with L. hoffmeisteri at low endrin concentrations, marker layer burial rate data did not suggest stimulation of reworking, as had previously been found for S. heringianus. At higher concentrations, reworking rates were equal to or slower than control rates early in experiments, followed by dramatic decreases thereafter. Reworking rates with mixed species (1:1 species ratio) suggested that the presence of S. heringianus enhanced the reworking response of L. hoffmeisteri. Post-experimental worm dry weights were inversely related to high sediment concentrations for both species. Reductions in post-experimental L. hoffmeisteri mortalities and increases in L. hoffmeisteri dry weights in mixed species tests at high endrin concentrations implied that L. hoffmeisteri benefits from the presence of S. heringianus, although the reverse was not observed. High final sediment endrin concentrations in the upper three cm implied worm mediated upward contaminant transport. Bioaccumulation factors for S. heringianus ranged from 9.7 to 43.8 and were consistently three to four times greater than bioaccumulation factors for L. hoffmeisteri (1.7 to 13.6).

Toxicity of 4-Nonylphenol to Tubifex tubifex and Chironomus riparius in 28-Day Whole-Sediment Tests

“…Indications of these toxic e!ects were also obtained by the reduced burrowing activity of worms, already observed by Meller et al (1998) in a 72-h test with increasing concentrations of copper, lindane, and hexachlorobenzene. As pointed out by Keilty et al (1988) and then by Meller et al, (1998), the decreased burrowing activity was accompanied by a reduction of worm biomass which was not quantitatively determined in the present research. No autotomy of the caudal region was observed as a detoxi-"cation process; this mechanism, observed in several oligochaetes (Roberts and Dorough, 1984;RoK mbke and Knacker, 1989;Meller et al, 1998;Lucan-Bouche`et al, 1999), may protect the animals against the increase of internal concentrations of toxic substances (metals in particular).…”

Biological Responses of Lumbriculus variegatus Exposed to Fluoranthene-Spiked Sediment

“…Previous studies demonstrated reduced biological burial with increasing exposure to contaminants. For the oligochaetes Stylodrilius heringianus and Limnodrilius hofmeisteri, the biological burial rate was similar or lower than controls with increasing sediment concentrations of endrin in sediment (Keilty et al 1988a(Keilty et al , 1988b. Such reductions have also been observed with a marine polychaete, Heteromastus filiformis, exposed to DDT (Mulsow and Landrum 1995).…”

“…Of the bioassays used for assessing effects on oligochaetes, sediment-reworking rates (determined as biological burial rates of a marker layer) have proven to be a sensitive indicator of oligochaete response to contaminant concentrations in sediments (Keilty et al 1988b(Keilty et al , 1988cKeilty and Landrum 1990). The approach uses the conveyor-belt feeding activity of the oligochaete to bury a radiolabeled marker layer in sediment.…”

“…Several species have been investigated for application in freshwater sediment bioassays (Bailey and Liu 1980;Keilty et al 1988aKeilty et al , 1988bKeilty et al , 1988cReynoldson et al 1991). Currently, the oligochaete Lumbriculus variegatus is the recommended organism for determining bioaccumulation of sediment-associated contaminants in fresh water (US EPA 2000;ASTM 2000) and has been used as a toxicity bioassay organism (Bailey and Liu 1980;Ankley et al 1991;Kukkonen and Landrum 1994;Monson et al 1995;Drews 1997).…”

Short-Term Toxicity of Lindane, Hexachlorobenzene, and Copper Sulfate to Tubificid Sludgeworms (Oligochaeta) in Artificial Media

“…Additionally there is the risk of increased transmission of chemicals within the food chain if the animals accumulate the substances and are more easily preyed on because they are on the sediment surface. Keilty et al (1988b) noticed a change in the reworking behavior of tubificids during longterm studies, using a labor-intensive Cs marker layer burial technique, at concentrations three to five magnitudes lower than the LC (96 h). However, the experiments with lindane-or copper sulfate-contaminated sediment described here demonstrate that the reworking activity of the examined tubificids was already reduced within 72 h. Using this method, no complicated or costly equipment was necessary to assess changes in reworking activity.…”