P. Egeler et al., Bioaccumulation test with Tubificid Sludgeworms in artificial media - development of a standardisable method, HYDROBIOL, 406, 1999, pp. 271-280
Lipophilic chemicals entering aquatic ecosystems often tend to adsorb to se
diments. Although often not bioavailable to pelagic organisms, these compou
nds can be subject to bioaccumulation and thus pose a potential threat for
sediment-dwelling organisms. The assessment of bioaccumulation is currently
based on the extrapolation of fish bioconcentration data. Thus, measuring
the bioaccumulation in benthic organisms gives more detailed information on
the hazard of chemicals for aquatic ecosystems. The freshwater tubificids
Tubifex tubifex and Limnodrilus hoffmeisteri were chosen as test organisms.
Breeding of the oligochaetes as well as bioaccumulation studies were carri
ed out in a system consisting of artificial sediment and reconstituted wate
r. C-14-lindane (gamma-hexachlorocyclohexane, gamma-HCH) and C-14-hexachlor
obenzene (HCB) served as model substances. Additionally, C-14-3,4-dichloroa
niline (3,4-DCA) was tested. Uptake and elimination of lindane and HCB were
examined. Bioaccumulation factors (BAF) were determined from the ratio of
concentration in oligochaete tissue to concentration in sediment. The tubif
icids accumulated C-14-lindane, C-14-HCB, and C-14-3,4-DCA by factors of 4.
7 (mean value; n = 4), 6.6 (mean value; n = 4) and 13.2, respectively, base
d on wet weight and radioactive concentrations. No major metabolites were d
etected in worms, sediment and water. Elimination kinetics were examined fo
r C-14-lindane and C-14-HCB. When transferred to clean sediment, the worms
eliminated both test substances rapidly and nearly completely. The tubifici
d bioaccumulation factors are contrasted with corresponding fish bioconcent
ration factors from literature. The presented data indicate once more that
the assessment of bioaccumulation based exclusively on lipophilicity and on
the extrapolation of fish bioconcentration data to other organisms or envi
ronmental compartments is not appropriate.