E171, a mixture of titanium dioxide, has been widely used as a food additive due to its whitening effect and low toxicity. However, it has been proven that E171 is no longer safe for public health. So far, there are insufficient studies on the toxic effects of E171 on organisms especially using standardized test methods. In this study, toxicity assessments of E171 to two aquatic species, water flea (Daphnia magna) and zebrafish (Danio rerio), were performed using modified standardized test methods based on the physicochemical properties of E171. The hydrodynamic diameter, polydispersity index, and turbiscan stability index (TSI) were measured to ensure the dispersion stability of E171 in exposure media during the test period. The EC50 for immobilization of water flea was 141.7 mg L-1 while zebrafish was not affected until 100 mg L-1 of E171. Measurements of reactive oxygen species (ROS) and antioxidant enzyme activities confirmed that E171 induced oxidative stress, leading to the activation of superoxide dismutase and catalase in both water flea and zebrafish, although the expression of antioxidant enzyme genes differed between species. These results suggested the potential risk of E171 to aquatic organisms and provided toxicological insights into the impacts of E171 on the environment.

Behavioral reaction can be measured as a sensitive endpoint for sublethal toxicity of copper, and can be used to obtain easily and quickly. Also behavioral endpoints may serve as a more insightful evaluation tool of the ecological effects of toxic chemicals. In this study, four invertebrates in freshwater which are usually used indicate species for water quality were selected as test species (Chironomus riparius, Heterocypris incongruens, Daphnia magna, and, Triops longicaudatus). Each test species was exposed to copper for 6 hours, and total distance, velocity, and, turn angle were measured for 1 hour using video analysis system (Ethovision : Noldus Information Technology) in laboratory condition. Each endpoints reflected effect of copper toxicity appropriately for all test species. These endpoint have possibility that can be used to identify characteristic behavioral responses to a metal toxicity. We viewed this study as a preliminary experiment for future research to investigate the significance of behavioral endpoints to various toxic chemicals.

Acetaminophen (CAS 103-90-2) is one of the most used pharmaceuticals around the world. In Korea, it was produced 1,069 tons in 2003. This chemical is not eliminated in wastewater treatment plant and may flow into the ecosystem through various routes. Therefore, there is a possibility that it can make an adverse effect on aquatic organisms. To examine its ecological toxicity, we used three native Korean aquatic invertebrate species, Daphnia sp., Chironomus yoshimatsui, and Ephemera orientalis. The acute toxicity on Daphnia sp. was moderately high, and its 48 hour median immobilization concentration (EC50-immobilization) was 51.7 mg/L. On the other side, the reproductive toxicity was very high, and its EC50 of 25 day reproduction test was 0.005 mg/L. In E. orientalis egg hatching test, the median egg hatching inhibition concentration was 0.199 mg/L. C. yoshimatsui was most tolerant to acetaminophen, in which 48 hour median lethal concentration (LC50) was 400.0 mg/L and 45 day median emergence inhibition concentration (EC50-emergence) was 45.27 mg/L. From this results, we concluded that acetaminophen is hazardous to freshwater macroinvertebrates, especially to water flea. Therefore we need to study more about pharmaceuticals' ecotoxicology including acetaminophen and to assess their potential ecological risk.

생태계를 평가하기 위한 평가법으로 주로 사용되는 이화학적 측정 평가법은 객관적인 측정치를 제시하는데는 용이하다. 그러나 단지 측정치의 단순한 평균이나 최고치만으로는 타 인자와의 복합 효과 또는 지속 시간에 의한 가중 효과 때문에 실상을 나타낼 수 없는 경우가 많다. 이에 따라 이화학적 측정치들을 객관적으로 종합하여 생태계의 상태를 파악할 필요성이 보다 중요하다. 즉 key factor나 trigger factor와 같은 생물체의 내성과 관련이 있는 인자