• Journal of Ecology and Environment
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• 제41권11호
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• pp.318-327
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• 2017

Background: A typical sewage treatment plant is designed for organic and nutrient removal from municipal sewage water and not targeted to eliminate micropollutants such as pesticides, pharmaceuticals, and nano-sized metals which become a big concern for sustainable human and ecological system and are mainly discharged from sewage treatment plant. Therefore, despite contaminant removal by wastewater treatment processes, there are still remaining environmental risks by untreated pollutants in STP (sewage treatment plant) effluents. This study performed aquatic toxicity tests of raw wastewater and treated effluents in two sewage treatment plants to evaluate toxicity reduction by wastewater treatment process and analyze concentration of contaminants to reveal potential toxic factors in STP effluents. Methods: Water samples were collected from each treatment steps of two STPs, and acute and chronic toxicity tests were conducted following USEPA (United States Environmental Protection Agency) and OECD (Organization for Economic Cooperation and Development) guidelines. Endpoints were immobility for mortality and reproduction effect for estrogenicity. Results: Acute $EC_{50}s$ (median effective concentration) of influents for Seungki (SK) and Jungnang (JN) STPs are $54.13{\pm}32.64%$ and $30.38{\pm}24.96%$, respectively, and reduced to $96.49{\pm}7.84%$ and 100%. Acute toxicity reduction was clearly correlated with SS (suspended solids) concentration because of filter feeding characteristics of test organisms. Chronic toxicity tests revealed that lethal effect was reduced and low concentration of influents showed higher number of neonates. However, toxicity reduction was not related to nutrient removal. Fecundity effect positively increased in treated wastewater compared to that in raw wastewater, and no significant differences were observed compared to the control group in JN final effluent implying potential effects of estrogenic compounds in the STP effluents. Conclusions: Conventional wastewater treatment process reduced some organics and nutritional compounds from wastewater, and it results in toxicity reduction in lethal effect and positive reproductive effect but not showing correlation. Unknown estrogenic compounds could be a reason causing the increase of brood size. This study suggests that pharmaceutical residues and nanoparticles in STP effluents are one of the major micropollutants and underline as one of estrogenic effect factors.

• Ocean Science Journal
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• 제40권2호
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• pp.91-100
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• 2005

Bioassay using the marine bacteria, Vibrio fischeri and rotifer, Brachionus plicatilis, and chemical analyses were conducted to assess the toxicity of the various sewage sludges, one of the major ocean dumped materials in the Yellow Sea of Korea. Sludge elutriates extracted by filtered seawater were used to estimate the ecotoxicity of the sludge. Chemical characterization included the analyses of organic contents, heavy metals, and persistent organic pollutants in sludge. Bacterial bioluminescent inhibition (15 min), rotifer mortality (24 hr) and rotifer population growth inhibition (48 hr) assay were conducted to estimate the sludge toxicity. EC50 15 min (inhibition concentration of bioluminescence after 15 minutes exposed) values by Microtox(R) bioassay clearly revealed different toxicity levels depending on the sludge sources. Highest toxicity for the bacteria was found with the sludge extract from dyeing waste and followed by industrial waste, livestock waste, and leather processing waste. Clear toxic effects on the bacteria were not found in the sludge extract from filtration bed sludge and rural sewage sludge. Consistent with Microtox(R) results, rotifer neonate mortality and population growth inhibition test also showed highest toxicity in dyeing waste and low in filtration bed and rural sewage sludge. High concentrations of persistent organic pollutants (POPs) and heavy metals were measured in the samples from the industrial wastes, leather processing plant waste sludge, and urban sewage sludge. However, there was no significant correlation between pollutant concentration levels and the toxicity values of the sludge. This suggests that the ecotoxicity in addition to the chemical analyses of various sludge samples must be estimated before release of potential harmful waste in the natural environment as part of an ecological risk assessment.

• 대한환경공학회지
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• 제27권2호
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• pp.191-197
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• 2005

Ceriodaphnia dubia를 이용한 새로운 독성시험법인 온도증가 단기독성평가법(ToxTemp, ToxCity test based on TEMPerature control)을 이용하여 농약성분에 대한 민감도를 조사하였다. BPMC, Diazinon, Fenitrothion등 하수의 생물학적 처리에 독성을 나타낼 수 있는 물질들에 대하여 기존의 실험방법인 표준 48시간 독성시험법과 비교했을 때 온도증가법은 $1{\sim}1.5$시간의 짧은 접촉시간에도 농약의 독성을 잘 감지할 수 있음을 알 수 있었다. 또한 중금속, 독성 유기화합물 그리고 농약성분을 비교, 평가했을 때 온도증가법은 1.25시간의 짱은 접촉시간 내에 48시간독성법의 결과와 높은 상관관계를 유지하며 독성을 감지하였다. 염색공단 폐수와 하수 등 실폐수에서의 독성평가능을 검토하기 위하여 활성슬러지를 이용한 질산화율, 산소이용율(OUR)과 C. dubia를 이용한 표준 48시간 독성시험법, 온도증가법을 비교하였다. 그 결과 OUR을 이용한 평가에서는 비교적 높은 질산화율 저해도를 보인 원수에 대해서도 독성민감도가 낮아 현장적용에 한계를 나타낸 반면 C. dubia를 이용한 표준 48시간 독성시험법과 온도증가법은 각기 다른 수준의 독성에 대해 민감하게 차이를 보였으며, 이 두 방법은 질산화율 저해도와 좋은 상관관계를 보였다. 온도증가법은 표준 48시간 독성시험법에 비해 1.5% 정도 민감도가 떨어지지만 현장에서의 신속한 감지가 가능하다는 점에서 현장에서의 질산화 독성진단에 대한 적용가능성이 높음을 보여주었다.

• 상하수도학회지
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• 제27권5호
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• pp.603-610
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• 2013

According to industrialization, increased toxic chemicals discharge has been causing water pollution. Especially domestic sewage is a major source of water pollution. Sixty percent of the total wastewater discharged is domestic sewage. Self-purification capacity of rivers and streams is drastically reduced by the emission of domestic sewage, industrial wastewater and livestock wastewater. Although domestic sewage is managed by implementing standards and regulations, toxicity effect of domestic sewage to humans and the environment is not yet clearly understood. In this study, by using daphnia magna, the ecotoxicity of domestic swage was assessed. Cl, Cu, Pb, COD, T-N, DO, pH and residual chlorine were investigated as background concentrations. The experiments were conducted with water samples obtained from three local sewage treatment plants. The experiment results indicated that higher level of toxicity corresponds to the higher pollution concentrations. The higher level of combinations of background concentrations such as heavy metals leads to the worse ecotoxicity. Especially, the Cu concentration affects the TU value.

• 한국환경농학회지
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• 제23권4호
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• pp.258-263
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• 2004

생물검정법에 의한 토양 내 독성평가의 유용성을 확인하기 위해 두 종류의 하수슬러지를 7년간 연용한 토양을 $Microtox^{(R)}$ 생물검정법과 상추종자 뿌리 신장법을 사용하여 독성을 평가하였다. 이 방법들은 하수오니의 종류나 시용량에 따른 토양의 독설 정도를 잘 평가 할 수 있었다. 상추종자 뿌리 신장법은 특별한 장비나 복잡한 처리 없이도 유의성 있는 결과를 구할 수 있었고 $Microtox^{(R)}$ 검정법은 전반적으로 재현성과 감도에서 유의성이 있었으며 또한 유기화합물에 대한 종합적인 평가도 가능하였다. 하수오니와 같이 다양한 화합뭍이 혼재되어 있는 유기성 자원의 토양 시용시 기존의 제한된 화학성분의 토양 분석법만으로는 독성평가에 한계가 있고 또 개별적으로는 별 영향이 없더라도 여러 화합물이 복합적으로 존재할 때 나타나는 독성작용에 대한 평가는 더욱이 어렵다. 그러므로 이러한 영향을 종합적으로 평가할 수 있는 생물검정법이 토양의 독성평가에서 화학분석법을 보완하는 평가방법으로서의 중요성은 충분하다고 할 수 있다. 그리고 생물독성법의 유용성을 높이기 위해서는 생물검정법의 시료 추출방법 개선과 실험의 재현성을 높이기 위한 노력이 필요하리라 생각된다. 따라서 이런 생뭍검정법의 많은 제약에도 불구하고 환경의 종합적인 평가에 있어서 생물검정법의 중요성은 대단히 크며 직접적으로 생물을 이용하는 방법뿐만 아니라 유전독성 평가방법 등 다양한 방법들이 환경독성 평가에 응용될 수 있을 것으로 판단된다.

• 한국환경과학회지
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• 제14권12호
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• pp.1129-1139
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• 2005

A series of experiments was conducted to identify the potential of five phytoplankton species as standard test species for marine ecotoxicological tests. The candidate phytoplankton species are Skeletonema costatum, Heterosigma akashiwo, Prorocentrum micans, Isochrysis galbana, and Tetraselmis suecica. Salinity tolerance and sensitivity on potassium dichromate as a reference material were identified. Toxicity of eleven ocean dumped sewage sludges and four red tide expellent extracts were estimated by the inhibition of population growth rates (PGR) of marine diatom S. costatum, While most species revealed relatively weak tolerance on salinity, T. suecica demonstrated the highest salinity tolerance ranged from $5\~35$ psu and the others $15\~35$ psu. H. akashiwo revealed the highest sensitivity as 72h $IC_{50}$=0.76mg/L and T. suecica the lowest as 72h $IC_{50}$=8.89mg/L on potassium dichromate. Sludge extracts from industrial waste, domestic sewage and livestock farm waste sludge showed high toxicity as 72h $IC_{50}$<$2\%$ and lowest toxicity from filtration bed sludge as 72h $IC_{50}$=$30.50\%$ NOEC (No Observed Effective Concentration) of sludge extract ranged from <$0.4\%$ to $1.6\%$ and this indicated high phytotoxicity of ocean dumped sewage sludge. The test sensitivity of phytoplankton PGR inhibition was much higher than those of marine rotifer Brachionus plicatilis mortality test and bioluminescent inhibition test by marine bacteria Vibrio fischeri, and comparable with the sea urchin (Strongylocentrotus intermedius) fertilization test. As a result the phytotoxicity test using phytoplankton PGR inhibition ($IC_{50}$) must be a useful tool for marine phyto-toxicological evaluation of ocean dumped materials.

• 한국물환경학회지
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• 제30권1호
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• pp.80-86
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• 2014

Unlike to natural organic matters (NOMs), effluent organic matters (EfOMs) are not well understood due to their complexity and heterogeneity. In this study, EfOMs from sewage and industrial wastewater treatment effluents and Suwannee River NOM (SRNOM) were isolated into hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) fractions. Specific ultraviolet absorbance (SUVA) and fluorescence excitation emission matrix (FEEM) analyses were used to characterize physicochemical properties. In addition, acute toxicity and oxidative stress to Daphnia magna were evaluated to characterize toxicological properties. EfOMs showed similar properties to microbially derived organic matters having low hydrophobicity, which are totally different from SRNOM having high hydrophobicity. Moreover, acute toxicity and antioxidant enzyme activity in D. magna was largely dependent on fraction types of EfOMs. These findings suggest that EfOMs have different physicochemical and toxicological properties compared with those of NOMs, which needs to be further identified with various sources of EfOMs.

• Environmental Analysis Health and Toxicology
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• 제25권1호
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• pp.11-18
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• 2010

Toxicity assessment of ocean dumping wastes (dye waste, urban sewage, food waste) were examined in the fertilization and embryo development rates of the Sea Urchin, Hemicentrotus pulcherrimus. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiments were began within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. The fertilization and embryo development rates in the control condition (not including ocean dumping wastes sludge elutriate) were greater than 90%, but suddenly decreased with increasing of ocean dumping waste sludge elutriate concentrations. The fertilization and normal embryogenesis rates were significantly inhibited in all waste sludge elutriate from dye waste ($EC_{50}$=4.37; $EC_{50}$=1.76), urban sewage ($EC_{50}$=5.79; $EC_{50}$=2.00) and food waste ($EC_{50}$=7.68; $EC_{50}$=2.16), respectively. The NOEC (<3.13) and LOEC (3.13) of fertiliztion and normal embryogenesis rates very similar in all waste sludge elutriate. These results suggest that biological assay using the fertilization and embryo development rates of H. pulcherrimus are very useful test method for the ecological toxicity assessment of ocean dumping wastes.

• Environmental Analysis Health and Toxicology
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• 제24권1호
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• pp.25-32
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• 2009

Toxicity of ocean dumping wastes(dye waste, urban sewage, food waste) were examined by observing fertilization and embryo development rates of the Sea Urchin, Strongylocentrotus nudus. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiments were began within 30 min after the collection of both gametes. The fertilization and embryo development rates tests were performed for 10 min and 48 h after fertilization, respectively. The fertilization and embryo development rates in the control condition(not including ocean dumping wastes sludge elutriate) were greater than 90%, but markedly decreased with increasing concentrations of ocean dumping waste sludge elutriate. The fertilization and normal embryogenesis rates were significantly inhibited in all waste sludge elutriate from dye waste($EC_{50}$=5.76; $EC_{50}$=4.53), urban sewage($EC_{50}$=9.82; $EC_{50}$=9.67) and food waste($EC_{50}$=3.90; $EC_{50}$=3.27), respectively. The NOEC(>3.13%) and LOEC(3.13%) of fertiliztion and normal embryogenesis rates very similar in all waste sludge elutriate. These results suggest biological assay using the fertilization and embryo development rates of S. nudus are very useful test method for the ecological toxicity assessment of ocean dumping wastes.

• 한국물환경학회지
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• 제18권2호
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• pp.189-199
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• 2002

Nitrogen, in its various forms, can deplete dissolved oxygen levels in receiving waters, stimulate aquatic growth, exhibit toxicity toward aquatic life and affect the suitability of sewage for reuse. Pilot-scale Rotating Biological Contactor(RBC) experiments were conducted to examine biological nitrification, respectively, of municipal sewage with five different internal recirculation ratios of 0, 1, 2, 3, and 4 using the constant hydraulic loading of $205L/m^2{\cdot}day$. The use of internal recirculation improved nitrification on account of the dilution of biodegradable organic carbon in influent sewage down to 15 mg/L of $SBOD_5$ or less. Ammonium nitrogen of $14.3{\pm}2.4%$ was consumed by cellular assimilation without the occurrence of denitrification. The thickness of biofilm didn't seem effect significantly the nitrification and denitrification. Nitrification with internal recirculation was found to occur using hydraulic loading rate of as high as $205L/m^2{\cdot}day$, which was beyond the generally known values of it.