인간의 인위적 활동으로 인해 발생하는 중금속 중 카드 뮴 (Cd)과 아연 (Zn)은 다양한 경로를 통해 하천으로 유입 되어 서식생물에게 유해 영향을 준다. 본 연구에서는 도심 하천에서 우점하는 장수깔따구 (Chironomus plumosus)를 이용하여 Cd와 Zn 노출에 따른 생태독성학적 반응을 연구 하였다. 생활사를 고려하여, 생존율, 성장율, 우화율, 성비와 하순기절 기형을 관찰하였다. 장수깔따구 생존율은 Cd 와 Zn 노출에 따라 시간, 농도의존적인 경향을 나타냈다. 성장율은 Cd 노출 후 Day 4와 Day 7, 농도의존적인 감소를 보였으며, 고농도인 50 mg L-1에서 대조군에 비해 급격한 감소를 나타냈다. 또한, 우화율은 10, 50 mg L-1 Cd에서 대조군에 비해 감소함을 관찰하였다. 성비 변화는 100 mg L-1 Zn에서 암컷의 비율이 증가였으나 농도가 높아짐에 따라 수컷의 비율이 높아짐을 보이며 성비불균형이 관찰되었다. 게다가, 장수깔따구의 하순기절에서는 대조군에 비해 Cd와 Zn 노출된 장수깔따구에서 기형이 관찰되었다. 이와 같은 결과는 수생태계로 유입되는 중금속이 하천의 하상저층에 서식하는 저서무척추동물에게 유해한 영향을 주며, 중금속 노출에 따른 생물학적 분석을 위한 현장 지표 종으로서의 가능성을 보여주었다.

Heavy metals resulted from the increase of human industrial activity are introduced into the environment through rainfall and wastewater, and have harmful effects on inhabitants. In this study, we investigated biological responses such as survival rate, growth rate, emergence rate and sex ratio, and morphological effects of mentum deformity in Chironomus plumosus, an indicator organism to evaluate pollutions on aquatic ecosystem. The survival rate of C. plumosus showed time- and dose-dependent decrease after chromium and copper exposures. Growth rate decreased at 4th day after chromium exposure and significantly reduced at exposure to relatively high concentration (copper 1000 mg L-1) for all exposure times. In addition, we observed that the emergence rate by exposure to copper 1000 mg L-1 was significantly lower than that of the control group. The imbalance of sex ratios showed at relatively low concentrations (chromium 10 and 50 mg L-1) with the high proportion of female and at the relative high concentration (copper 1000 mg L-1) with the high proportion of male. Furthermore, the morphological mentum deformities of C. plumosus observed in the exposed group according to chromium and copper exposure. These results suggest that the heavy metal exposure in environment may influence biosynthetic and morphological stresses of benthic invertebrate C. plumosus, and aquatic midge C. plumosus are potential indicators for toxicity assessment of heavy metals such as chromium and copper.

Chironomous is aquatic insect belonging to order Diptera, family Chironomidae. Their larval stage can be found mainly in aquatic benthic environment, hence good model organism to study environmental toxicology assessments and consider as useful bio indicators of contamination of the aquatic environment. In this study, Chironomus Heat Shock Proteins, Cytochrome 450, Glutathione S-transferase, Serine-type endopeptidase gene expressions were compared between polluted field areas (Chironomus plumosus) and under laboratory conditions (Chironomus riparious) to investigate molecular indicators for environmental contaminant stress assessment. Heavy metal (Al, Fe, Mn, Cu, Cr, Zn, Se, Pb, As, Cd) concentrations in sediments collected from three study areas exceeded the reference values. Moreover, HSPs, CYP450 and GST gene expression except SP for C. plumosus showed higher expression than C. riparious gene expression. Similar gene expression pattern was observed in C. riparious that exposed environment waters up to 96 h when compared to C. plumosus exposed to waters that grown in lab conditions. In summary, this comparative gene expression analysis in Chironomous between field and laboratory condition gave useful information to select candidate molecular indicators in heavy metal contaminations in the environment.