• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.2
• /
• pp.198-205
• /
• 2005

This study was carried out to investigate the removal of TNT (2,4,6-trinitrotoluene) in the batch and continuous type microcosm systems consisting of marsh and pond. First, the batch reactor study showed that TNT (10 mg/L) was completely removed in the marsh and pond system within 20 days. The major reductive metabolites of TNT include 4-amino-2,6-dinitrotoluene (4-ADNT), 2-amino-4,6-dinitrotoluene (2-ADNT), 2,4-diamino-6-nitrotoluene (2,4-DANT), and 2,6-diamino-4-nitrotoluene (2,6-DANT). These metabolites concentration also decreased during further treatment. The continuous reactor systems combining marsh and pond indicated the similar pattern of TNT degadation and the metabolites production. Among the continuous reactor combinations, marsh-pond system showed more stable TNT removal and metabolites production. The toxicity of the effluent from the continuous system was examined by Microtox Assay using Vibrio fischeri. The result showed that the effluent toxicity was reduced below toxicity endpoint ($EC_{50}$) after continuous marsh pond system, indicating that metabolites of TNT are less toxic than TNT itself. Based on the results, TNT contaminated wastewater can be efficiently treated using marsh and pond wetland systems.

• Journal of Environmental Health Sciences
• /
• v.30 no.3
• /
• pp.185-190
• /
• 2004

Acute aquatic toxicity of effluents discharged from five dyeing plants in Gyeong-gi province were evaluated to assess whether the current Korean water quality standards(KWQS) could protect aquatic life. Chemical analyses of all parameters regulated under KWQS, except for E-coli, were also carried out to determine regulation compliance of the samples. All the effluent samples were satisfied with KWQS except for the color in only one sample. In acute Daphnia magna toxicity tests, significant mortality was observed in one of five samples and EC50 was 12.1%(95% confidence interval 9.1-16.2), which was in compliance with KWQS. The result of the Microtox assay indicated that acute microbial toxicity existed in effluents from three out of five plants, two of which were in compliance with KWQS. The agreement between regulation compliance of chemical concentrations of effluent and observed toxicity from various biological toxicity tests was very poor to fair (kappa = 0.194~0.250). The data presented suggest that exposure to dyeing wastewater which were in compliance with Korean water quality standards may not be safe to aquatic biota, and multiple tropical levels should be considered in aquatic toxicity monitoring of dyeing industry.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.2
• /
• pp.92-100
• /
• 2005

This study was conducted to find suitable methods for screening organic resources useful for compost. Twenty-seven industrial and domestic sludges were collected from various cities and industrial areas. Contents of organic matters in the sludges were in the range of 79.3-98.0%, and the contents were much higher than the regulation level (60%) for raw materials of compost. Contents of total nitrogen were in the range of 0.8-2.6%. Contents of Fe and Al were very high. Content of HEM was highest in textile sludge ($257mg\;kg^{-1}$) and the contents in the others were in the range of $12.6-90.3mg\;kg^{-1}$. Content of PAHs was lowest in food sludge ($739.1{\mu}g\;kg^{-1}$ and pulp-mill sludge had the highest PAHs content ($3461.8{\mu}g\;kg^{-1}$). $Microtox^{(R)}$ $EC_{50}$ values were higher in the sludges which were classified as a possible material in composting after analysis and investigation. Lettuce root elongation and $EC_{50}$ values were relatively lower in pulp-mill sludge, sewage sludge 3 (Large city), food sludge and leather sludge. Therefore, mineral nutrients, heavy metals, organic compounds (HEM, PAHs, PCBs), and bioassay ($Microtox^{(R)}$ $EC_{50}$, Relative root elongation test) are recommended to be included in the screening system of raw material of compost in addition to the current regulation with organic matter and 8 heavy metals.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2002.10a
• /
• pp.157-157
• /
• 2002

본 연구에서는 한강을 세 구간으로 구분하여 구간별 대표지점(의암호, 팔당호, 및 동호대교 정점)의 하상퇴적물을 grap으로 각각 채취한 후, Tandem Bioassays 을 적용하여 환경독성 수준을 평가하고 정점간 상호 비교하였다. Tandem Bioassays 이란 유해물질 오염에 의한 다양한 생태계 반응을 표현할 수 있는 최소한의 상호 보완적 환경독성 평가 체계를 의미한다. 본 연구에서 적용한 Tandem Bioassays 은 발광성미생물을 사용하는 Microtox 시험, 수서 물벼룩인 daphnia와 ceriodaphnia 시험, 그리고 개구리 배아를 이용하는 기형유발능 시험(최기형성 시험, FETAX)등으로 구성하였다.

• Korean Journal of Environmental Biology
• /
• v.23 no.2 s.58
• /
• pp.146-151
• /
• 2005

Recent studies indicated the utility of whole effluent assessment as a measure to control discharge of toxic effluents to receiving water in Korea. However, most studies have been focussed on acute lethal effects of toxic wastewater with little consideration of chronic sublethal impacts which are of growing concern in protecting aquatic ecosystem. We conducted acute and chronic toxicity tests with effluents discharged from five different dyeing plants in Gyeong-gi province using a marine bacterium Vibrio fischeri and a freshwater macroinvertebrate Daphnia magna to demonstrate the importance of assessing chronic sublethal effects. Various levels of acute and chronic toxicities were observed in many samples tested in this study. In 21-d chronic toxicity tests using D. magna all samples showed effects on reproduction and growth. Notable mortalities were also noted in three out of five effluents. The result of the Microtox assay indicated that acute microbial toxicity existed in effluents from two out of five plants and acute daphnid toxicity was observed in only one effluent. The result of this study clearly suggests chronic toxicity tests are more suitable to assess biological effects of effluents because it was shown from this study that even an effluent with no acute toxicity could cause chronically lethal and/or sublethal adverse effects on aquatic biota which may affect the population dynamics in aquatic ecosystem.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.04a
• /
• pp.108-113
• /
• 2000

Freshwater borne bacteria transformed with luxAB-containing plasmid were optimized for the toxicity tests of various organic carbons and heavy metals. The EC$\sub$50/ values obtained from tests using the most sensitive bacterium to toxicants, YH9-RC, revealed to be much less than those from the Microtox$\^$/. In addition, some physiological characteristics of this bacterium under the toxic stress conditions such as potential bioluminescence, specific growth rate, and intracellular ATP contents, reproducibly and reliably correlated to the toxicity of the chemicals exposed. The higher concentrations of COD in wastewater samples, the lower EC$\sub$50/ values, therefore the developed toxicity test was found to be easily applicable to the toxicity test for wastewater samples and effluents. The conditions for constructing 384-multiwell plate containing freeze-dried bacterium were also optimized through the addition of 0.16 M trehalose before freeze-drying. Consequently, the advanced test system featuring a continuous measurement of the toxicity, an automated real-time monitoring of its results, and an alerting function was designed and constructed in combination with the microbiological, mechanical, and electronic compartment.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.3
• /
• pp.373-381
• /
• 2012

Antibiotics have been issued recently in water environments because of potential impacts on ecosystem and public health. This study was aimed to investigating the degradation of antibiotics such as tetracycline, lincomycin, sulfamethazine and cephradine using gamma ray irradiation. And the toxicity before and after irradiation on antibiotics was tested in order to examine the aquatic eco-risk assessment by aquatic organisms. In addition, comparing tests on toxicity for gamma ray and UV irradiated antibiotics was conducted. Four different antibiotics were prepared by concentration of 30 mg/L with demi-water respectively. The absorption dose of gamma ray was ranged from 0.2 to 2 kGy. The concentration of four antibiotics was gradually decreased corresponding to the increase of the absorption dose. A method for toxicity assessment using Pseudokirchneriella subcapitata was evaluated to the most acceptable compared with methods by Daphnia magna and Microtox$^{(R)}$ in terms of sensibility. It showed that the reduction of toxicity on antibiotics treated by gamma ray was superior comparing to the test results obtained from UV treatment. By-products from antibiotics treated by gamma ray were easily decomposed by microorganism and their toxicity was also evaluated to low.

• Journal of Korean Society on Water Environment
• /
• v.30 no.4
• /
• pp.403-408
• /
• 2014

The toxicity of heavy metals (Zn, Pb) and diesel, in single and binary solution was investigated using the photobacterium Vibrio fischeri (Microtox test) as a test organism. In this experiment, the concentration of water soluble fraction of diesel was based on the total petroleum hydrocarbon (TPH). The toxicity of each single compound showed the following $EC_{50}$ (15min): Zn 1.90 mg/L, Pb 0.31 mg/L, TPH 2.09 mg/L. The observed toxicity of binary mixtures increased, depending on the concentration of the mixed substance. The effects were defined as synergistic, antagonistic, or additive, in accordance with the sign of difference between the predicted and observed toxicity at binary mixtures. The interactive effects between zinc and lead were synergistic, on the other hand, antagonistic and additive effects were found in each metal and TPH mixtures on the bioluminescence of V. fischeri.

• Membrane and Water Treatment
• /
• v.14 no.1
• /
• pp.19-25
• /
• 2023

The studies on the effect of different plastic properties (e.g., types, shapes, presence of additivies) on the sorption of contaminants in the agricultural environment are limited. In this study, Cu and Pb, the commonly found heavy metals in the environment, were used to investigate the sorption capacities of microplastics (MPs). The Pb sorption capacity increased in the order of polystyrene (PS)<polyethylene (PE)<polyvinyl chloride (PVC). The estimated Cu sorption capacity was greater for the PE films than the PE fragments, while the sorption strength was greater for the PE fragments. This suggests that the shapes of MPs can affect the contaminant sorption capacities. With the PE fragments, the Pb sorption capacity was greater than the Cu sorption capacity by 10-12 times. Also, the Pb and Cu sorption capacities were greater for the PE fragments with additives than the PE fragment without additives. After the sorption of Pb or Cu on MPs, the toxic effects of the Pb or Cu solutions were decreased, suggesting that the toxic effects of contaminants can be affected by the co-presence of MPs in the environment. Overall, the results show that different types and shapes of MPs and the presence of additives can affect the heavy metal sorption capacities of MPs.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.5
• /
• pp.82-88
• /
• 2017

Contaminated sediment can be treated in order to reuse the treated sediment. Even though the chemical criteria are satisfied, the treated sediment could still impose toxic effects. Therefore, this study investigated the changes in the ecological toxic effects of the contaminated sediment from the J region in Singapore after treatment. The contaminated sediment was subject to sequential soil washing and thermal treatment, followed by pH neutralization. Toxic effects of the contaminated and treated sediments were determined by using Vibrio fischeri ($Microtox^{(R)}$), Triticum aestivum (wheat), and Eisenia foetida (earthworm). After treatment, the concentrations of total petroleum hydrocarbons and heavy metals were decreased by 98% and 59-93%, respectively, and satisfied the Industrial Maximum Values of the Dutch Standard, which were used as the remedial goal. The bioluminescence reduction of V. fischeri decreased significantly, and the earthworm survival increased from 0% to 90% after treatment. The germination rate increased from $0{\pm}0%$ to $75{\pm}13%$ after treatment, but the treated sediment may need additional treatment such as nutrient addition for better plant growth. Overall, this study showed that the treatment of the contaminated sediment satisfactorily removed mixed contaminants, and this led to reduction in toxic effects, suggesting improved potentials for reuse of the treated sediment.