Sublethal responses to endrin in sediment by Stylodrilus heringianus (Lumbriculidae) as measured by a 137cesium marker layer technique

Abstract

Sediment reworking rates of Stylodrilus heringianus (Oligochaeta: Lumbriculidae) were measured in microcosms containing sediments dosed with the chlorinated pesticide, endrin. Reworking rates were measured at 10°C by monitoring a ~37cesium marker layer burial in contaminated and uncontaminated microcosms. Endrin concentrations ranged from 3.1 to 42 000 ng/g dry sediment. Alterations in reworking rates were observed at sediment concentrations five and one half orders of magnitude below the LCs0 (1 650 #g/g). For the lower concentrations, marker layer burial rate data suggested possible stimulatory effects in the first 300 to 600 h, followed by significant rate decreases relative to controls. For higher concentrations, rates were equal to or slower than control rates in the first 600 h, followed by dramatic decreases in the last 600 h. High final surficial sediment endrin concentrations at the end of experiments implied worm mediated upward transport. Worm mortalities were 9.3 to 28% for the two highest concentrations (42 000 and 11 500 ng/g) and 0 to 6.7% for all other concentrations including controls. Post experimental worm dry weights were inversely related to high concentrations. Bioaccumulation factors ranged from 34 to 67 on a g dry organism to g dry sediment basis.

Biological mixing responses to sublethal concentrations of DDT in sediments by Heteromastus filiformis using a 137Cs marker layer technique

“…Rates at which sediments are ingested, deposited and subsequently re-buried have been mainly studied with freshwater invertebrates under both field and laboratory conditions , Krezoski 1981, Robbins et al 1984, Keilty et al 1988a. Most research on marine invertebrates involving chlorinated hydrocarbon contaminants has focused on contaminant bioaccumulation and depuration processes (Fowler et al 1978, Elder et al 1979, Schiff 1991.…”

Toxicology and Laboratory Studies

“…It is an important, ecologically relevant effect where oligochaete worms interact with sediments through pumping pore water and the active transport of particulate matter to surficial layers. The reworking activity by worms has been studied in relation to toxicity of chemicals sorbed to the sediment particles and was considered as the most sensitive endpoint because it is an integrated physiological response and incorporates toxicant bioavailability, organism compensatory mechanisms and organism function (Keilty et al 1988c). Oligochaete species ingest sediment particles from deep layers of sediment and deposit faeces on the surface, and rates at which sediments are transported to the surface have been determined under laboratory conditions.…”

Biological Responses of Lumbriculus variegatus Exposed to Fluoranthene-Spiked Sediment

“…With exposure to contaminants, sediment reworking rate will also be affected by the impact of the contaminants on the worms. When sediment reworking rates were used for the assessment of endrin-contaminated sediment, a reduction of the biological burial rate of a marker layer was observed at endrin sediment concentrations approximately four to five orders of magnitude lower than those required to produce mortality at 96 h and about 10-fold lower than concentrations that affect growth (Keilty et al 1988c). Sediment reworking rates have also proven useful for evaluating the impact of contaminants in field-collected samples (Keilty and Landrum 1990).…”

“…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).…”