• Journal of Environmental Health Sciences
• /
• v.30 no.4
• /
• pp.347-351
• /
• 2004

A battery of sediment bioassays was performed for the sediments from the intertidal flat zone along the middle west coast of Korea to assess their potential toxicity. In the bioassays, three crustaceans, Daphnia magna, Nitocra spines, and Hyalella aztec a were exposed to $16\%$ sediments (wet weight) collected from 14 sites. Immobility($\%$) was checked as an endpoint after 24- and 48-h exposure of Daphnia magna and after 96-h exposure of Hyalella azteca and Nitocra spines. Among the three bioassays, the 48-h Daphnia bioassay showed the most distinct differential sensitivity in relation to sediment contamination, while the Nitocra and the Hyalella bioassays failed to show the differential sensitivity properly among the sites classified as polluted. Significantly different levels of immobility ($\%$) were obtained between the sites classified as chemical/nutrient polluted and the sites classified as non-polluted in the Daphnia bioassays, but not in the Nitocra bioassay and the Hyalella bioassay. Some differences of toxic response to the same sediments among bioassays were observed, suggesting that there may be a chemical specificity of response sensitivity to sediment toxicity, due to differences in bio-availability of sediment toxicants among test species.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2001.11a
• /
• pp.89-89
• /
• 2001

• Environmental Analysis Health and Toxicology
• /
• v.22 no.2 s.57
• /
• pp.157-163
• /
• 2007

Tetrabromobisphenol A (TBBPA) is the most widely used BFR (brominated flame retardants) as a reactive flame retardant in printed circuit boards, and as additive applications in several types of polymers. The purpose of this study is to assess the adverse effects of TBBPA on the benthic amphipod (Hyalella azteca). Results on the acute toxicity of TBBPA using Hyalella azteca showed that NOEC and LOEC are 100mg/kg and 200mg/kg, respectively. In addition, when chronic toxicity of TBBPA was investigated at the concentration ranges between 0.01 to 100mg/kg, it was found that NOECs are $10mg/kg(fecundity){\sim}100mg/kg(viability)$, respectively. Significant fecundity inhibition was appeared at 100mg/kg of TBBPA, however, this concentration did not show severe adverse effect on weight increment. The values of PNEC were determined as 0.1mg/kg (fecundity) and 1mg/kg (lethal effect), respectively, using a safety factor suggested by EU and OECD.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2001.11a
• /
• pp.90-90
• /
• 2001

• Journal of Soil and Groundwater Environment
• /
• v.17 no.4
• /
• pp.1-8
• /
• 2012

The success of stabilization treatment in heavy metal contaminated sediment depends on the heavy metal bioavailability reduction through the sequestration of the heavy metals. This study was performed to assess the changes in the bioavailability of Pb or Cd in the Pb or Cd contaminated sediments by using birnessite and hydroxyapatite as stabilizing agents. The toxicity tests were carried out using a microorganism (Vibrio fischeri), an amphipod (Hyalella azteca) and an earthworm (Eisenia foetida). With Vibrio fischeri, the toxicities of both Pb and Cd were reduced by more than ten times in the presence of birnessite and hydroxyapatite compared to that of in the absence of birnessite and hydroxyapatite. The concentrations of Pb and Cd in the contaminated sediments were lethal to Hyalella azteca, however, in the presence of birnessite and hydroxyapatite more than 90%, on average, of Hyalella azteca survived. With Eisenia foetida, the bioaccumulated concentrations of both Pb and Cd were reduced by more than 75%, on average, lower with the addition of birnessite and hydroxyapatite to the contaminated sediments. These results show that the addition of birnessite and hydroxyapatite can reduce the bioavailability of Pb and Cd in contaminated sediments. In addition, the in situ and ex situ performance of birnessite and hydroxyapatite as stabilizing agents can be verified using the toxicity tests with Hyalella azteca and Eisenia foetida, respectively.

• Environmental Analysis Health and Toxicology
• /
• v.22 no.3
• /
• pp.271-277
• /
• 2007

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are fully flurorinated organic compounds which are highly persistent in environment and accumulated in organism. These chemicals are released to the environment at their manufacture, during their use in industrial and consumer applications and from disposal after their use. The purpose of this study was to determine the effects of PFOA and PFOS on the freshwater flea (Moina macrocopa). Acute toxicity test and chronic toxicity test were performed for 2 days and 10 days, respectively. Acute toxicity was assessed on the basis of mortality, while chronic toxicity was assessed by fecundity as well as mortality. The acute toxicity studies on PFOA and PFOS showed that the values of $LC_{50}$ were $73.9\;mg/L\;and\;27.7\;mg/L$ respectively. In the chronic toxicity test, fecundity was reduced significantly at 24.1 mg/L of PFOA and 9.3 mg/L of PFOS, respectively. Conclusively, the results of this work suggest that Moina macrocopa could be a suitable model organism for screening and assessing of environmental pollutants in water.