Abstract. The effects of the antiepileptic drug carbamazepine
(CBZ) were studied in three freshwater invertebrate species
representing different taxonomic groups, life histories, and
habitats in aquatic ecosystems. The oligochaete Lumbriculus
variegatus was exposed bywayof CBZ-spiked sediments at
nominal concentrations between 0.625 and 10 mg/kg dry
weight (dw) for 28 days. At the end of the test, reproduction
and biomass were monitored as end points. The nonbiting
midge Chironomus riparius was exposed to CBZ in a series of
tests at nominal CBZ concentrations in sediment ranging from
0.16 to 100 mg/kg dw at 20C and 23C. Emergence and
gender ratio were monitored at the end of the test. The
freshwater snail Potamopyrgus antipodarum as the third test
species was used in a chronic reproduction test for 28 days at
aqueous CBZ concentrations from 0.4 to 250 mg/L. Whereas
for the oligochaete and the snail no effects were observed, C.
riparius exhibited a significant and concentration-dependent
decrease of emergence in all test series. No observed effect
concentrations and 10% effect concentrations were in the
range of 33 to 140 and 70 to 210 lg/kg dw, respectively, based
on measured CBZ concentrations in sediments. These low
values indicate that CBZ maypose a potential threat for the
survival of C. riparius and probablyalso for other aquatic
insect populations in the field.