Mouthpart Deformities of Chironomus plumosus Larvae Caused by Increased Concentrations of Copper in Sediment from Carp Fish Pond

Abstract

Elevated concentrations of heavy metals in water can cause deformities of the mouthparts in chironomid larvae reared on artificial sediment. This investigation is an attempt to study effects of increased copper concentrations on mouthparts deformities of Chironomus plumosus larvae reared on natural sediment obtained from carp pond. Since the bioavailability of heavy metals is greater in artificial substrates than in natural ones usage of carp pond sediment, especially due to its low heavy metals content according to sediment quality guidelines, should provide more realistic assessment of biomarker potential of chironomid mouthparts deformities in biomonitoring of copper sediment pollution. It is demonstrated in the experiment that an increase of copper concentration in sediment leads to progressive increase in the frequency and severity of deformities of the mentum in C. plumosus larvae. Thus, shortening of median teeth in 2.0 +/- 0.2% individuals was the only deformity recorded in control tanks (at 15 mu gg-1 Cu), at 30 mu gg-1 Cu its frequency increased to 16 +/- 2%, and shortening of median-lateral teeth appeared at the same frequency, while at 60 mu gg-1 Cu frequency of both deformities increased to 24 +/- 2% and 28 +/- 4%, respectively, in addition to the appearance of tooth loss in 16 +/- 3% of individuals.