We evaluated the effect of water pH (6, 7, 8 and 9) and hardness (40mg/L and 160mg/L as CaCO3) on the growth of H. incongruens. Both water pH and hardness affected the growth parameter of H. incongruens such as head capsule width and maturity time. The head capsule width of the adults in the highest ph condition was 9.7% increased compared to the lowest ph condition. The maximum difference of the maturity time was 192 hours among the test conditions. Overall, as water ph level increase makes head capsule size of the test animal large, the inter-molt period and maturity time become shorter significantly. The effect of water hardness increasing showed a similar tendency with ph level. Especially, the difference of the growth parameter among the test conditions was increased by growing test animal. There are strong correlation between available amount of intake calcium and growth parameters of test animal. These results indicate that because of calcium demand for growth, water pH level and hardness are the important effect factor in life-cycle of the H. incongruens..

The use of insect growth regulators (IGRs) has been gaining popularity as an environmentally friendly option to improve existing integrated pest management (IPM) strategies. Although IGRs have a selective effect on target organisms, they may exert a more selective effect on non-target organisms. In this study, the toxic effects of teflubenzuron on biological traits of P. rosea, Collembola, were assessed in the OECD artificial soil under two different exposure conditions, one was exposed in the bulk soil, and the other was exposed in the compacted soil which unidirectional force was applied to the soil surface. After 28 days of exposure, the toxicity of teflubenzuron on the survival and juvenile production of P. rosea in the bulk system was more toxic than that of the compact system. Moreover, not only the egg production but also the hatching rate and molting frequency of P. roseas was decreased in a concentration dependent manner. These results suggest that the IGRs teflubenzuron exhibit significant impacts on the biological traits of non-target organisms P. rosea and its toxic effects are differently assessed depending on the exposure conditions.

Soil contamination can be one path for stream and groundwater contamination. In this study, the toxicity of soils sampled in the vicinity of the abandoned mine located in the Gyeonggi province was evaluated using freshwater organisms Heterocypris incongruens. Two different exposure scenarios, one is in the aqueous only exposure, and the other is in the aqueous + soil exposure. The seven different soil samples were tested depending on the contamination level; reference (1 soil), moderately contaminated (4 soils) and highly contaminated (2 soils). In the toxicity tests, H. incongruens were exposed to water extracts (aqueous only exposure) and soils (aqueous + soil exposure) which were serially two-fold diluted with either EPA moderate hardwater or clean sand, respectively. After 6 days of exposure, no significant impact on the survival was found in the both systems for reference soil, while only significant impact was found in the aqueous + soil system for moderately contaminated soil. And the survival of H. incongruens was dramatically decreased with decreasing dilution series for highly contaminated soils. Interestingly, the toxicity of aqueous + soil system was higher than that of aqueous only system, implying the exposure of chemicals to H. incongruens may be a consequence of its foraging behavior onto the surface of sediment. From the results of this study, the freshwater organism H. incongruens can be used as surrogate test species to assess the soil contamination.

Sedimentation of soil particles in water is perhaps the most significant pathway to contamination of aquatic ecosystems. In this scenario, the use of freshwater organisms for assessing sediment toxicity will be considered more ecologically relevant than tests that use aqueous soil extracts. To evaluate the toxicity of soils sampled in the vicinity of the abandoned mine located in the Gyeonggi province, Daphnia magna were exposed to a 1:4 of soil to water which soil samples were serially two-fold serially diluted with clean sand to concentrations ranging from 6.25 to 100 % % (w/w) for 24- and 48-h. Irrespective of exposure time, the survival of D. magna for reference soil was not decreased, while the survival of D. magna showed high sensitivity to the soils with moderate as well as high metal concentrations. Moreover, the heavy metal concentrations in the water samples increased with increasing the heavy metal concentrations in the soils, which indicates the increased sensitivity is the consequences of the bioavailable fraction of contaminants in soils. These results clearly showed that the freshwater organism D. magna can be used as test species to assess the potential impact of soil contaminants into aquatic ecosystems.