• Environmental Analysis Health and Toxicology
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• 제23권2호
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• pp.67-77
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• 2008

It has been observed that the linear relationship between the logarithm of bioconcentration factor (log BCF) of highly hydrophobic chemicals and their log $K_{ow}$ breaks when log $K_{ow}$ becomes greater than 6.0. Consequently, super hydrophobic chemicals were not thought to cause baseline toxicity as a single compound. Researchers often call this phenomenon as "hydrophobicity cutoff" meaning that bioconcentration or corresponding baseline toxicity has a certain cutoff at high log $K_{ow}$ value of hydrophobic organic pollutants. The underlying assumption is that the increased molecular size with increasing hydrophobicity prohibits highly hydrophobic compounds from crossing biological membranes. However, there are debates among scientists about mechanisms and at which log $K_{ow}$ this phenomenon occurs. This paper reviews three hypotheses to explain observed "cutoff": steric effects, kinetic or physiological limitations, and chemical activity cutoff. Although the critical molecular size that makes biological membranes not permeable to hydrophobic organic chemicals is uncertain, size effects in combination with kinetic limitation would explain observed non-linearity between log BCF and log $K_{ow}$. Chemical activity of hydrophobic chemicals generally decreases with increasing melting point at their aqueous solubility. Thus, there may be a chemical activity cutoff of baseline toxicity if there is a critical chemical activity over which baseline effects can be observed.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권1호
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• pp.49-62
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• 2023

Phthalates are animal carcinogens. Potassium hydrogen phthalate (KHP), which has the least complicated structure among phthalates, is used for the analysis of total organic carbon and formaldehyde. However, its toxicity has not been confirmed. A 24-hour acute toxicity test was performed using Daphnia magna, a water flea used to evaluate aquatic toxicity owing to its high sensitivity. The lowest observed effect concentration of KHP was found to be 240 mg/L. The effects of phosphorus, nitrogen, and Cr(6+), which are able to be discharged along with KHP, were also confirmed using tests. At 240 mg/L KHP, toxicity increased as phosphorus, nitrogen, and Cr(6+) increased. In addition, tests were performed to confirm the half maximal effective concentration of KHP. Through 10 test repetitions, the average ecotoxicity value was found to be 0.3, the average half maximal effective concentration was 327.75 mg/L, and the coefficient of variation (%) was 3.16%; because the latter value is lower than 25%, which is what is generally suggested for the water pollution standard method, the reproducibility of the tests is sufficient to replace the existing standard reference toxicity test that uses potassium dichromate. In addition, the half maximum effective concentration of potassium hydrogen phthalate is approximately 218 times more than that of potassium dichromate; therefore, toxicity is relatively low. In conclusion, KHP is a feasible alternative to the highly toxic potassium dichromate for performing the standard reference toxicity test.

• 한국양봉학회지
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• 제34권4호
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• pp.315-323
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• 2019

Large amounts of sludge produced by paper mill industries represent one of the most serious environmental problems in the world. Recently, beekeepers living in the neighborhood of the paper mill in Hwasan County, Youngcheon city, GB, Korea, became alarmed that honey bee colonies were dying off suddenly across the neighborhood. A preliminary study was conducted to evaluate the toxicity (oral, fumigation, repellent) of recycled solid paper mill sludge (SPMS) and leachate paper mill sludge (LPMS) to honey bee workers under laboratory conditions, and to analyze the volatile organic compounds(VOC). The SPMS and LPMS were separately subjected to a liquid-liquid extraction (LLE) at three temperatures to extract VOC(highest VOC yields: 1.52% SPMS and 0.34% LPMS). A total of 70 chemicals were detected in the VOC of paper mill sludges, of which 49 and 21 volatile organic compounds from SPMS and LPMS, respectively. The SPMS was dominated by high degree presence of stanols (saturated sterols), such as cholestanol, cholestan-3-ol and also saturated hydrocarbons. However, LPMS was characterized by the absence of sterols. Both SPMS and LPMS showed an influence on the olfactory behavior of honey bee on Y-tube assay, with repulsion rates of 72 and 68%, respectively. Both SPMS and LPMS at concentration of 100mg/mL caused higher honey bee oral mortality than the untreated controls at 48, 72, 96 and 120 hours after treatment(highest oral mortality at 120 hr: 85.74%(SPMS); 93.51 % (LPMS)). A similar pattern was observed when honey bees were tested to fumigant toxicity. Both SPMS and LPMS caused significant higher mortality than the untreated control 24 hour after the exposure (highest fumigation mortality at 120 hr: 69.4% (SPMS); 56.8% (LPMS)). These preliminary results indicated that paper mill sludge could be partly responsible for sudden death and disappearance of honey bees, especially in hot humid summer days. With climate change, the risk of environmental chemical exposure to honey bee would pose greater attention.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.77-86
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• 2020

Persulfate-based advanced oxidation processes (AOPs) can oxidize various organic pollutants. In this study, persulfate/Fe(II) system was utilized in phenol removal, and the effect of various organic and inorganic chelators on Fe(II)-medicated persulfate activation was investigated. The feasibility of persulfate/Fe(II)/chelator in cleanup of phenol-contaminated sediment was confirmed through toxicity assessment. In persulfate/Fe(II) conditions, the rate and extent of phenol removal increased in proportion to persulfate concentration. In chelator injection condition, the rate of phenol removal was inversely proportional to chelator concentration when it was injected above optimum ratio. Thiosulfate showed greater chelation tendency with persulfate than citrate and interfered with persulfate access to Fe(II), making the latter a more suitable chelator for enhancing persulfate activation. In contaminated clay sediment condition, 100% phenol removal was obtained within an hour without chelator, with the removal rate increased up to four times as compared to the rate with chelator addition. A clay sediment toxicity assessment at persulfate:Fe(II):phenol 20:10:1 ratio indicated 71.3% toxicity reduction with 100% phenol removal efficiency. Therefore, persulfate/Fe(II) system demonstrated its potential utility in toxicity reduction and cleanup of organic contaminants in sediments.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.196-201
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• 2000

The influence of adsorption on cadmium toxicity to soil microorganisms in smectite-rich soils and sediments was quantified as a function of solution and sorbent characteristics. Adsorption and surface complexation experiments were conducted to infer Cd sorption mechanisms to a reference smectite and three fractions of a Veritsol soil, and to elucidate the effects of the surface complexation on Cd bioavailability and toxicity in soils and sediments. Cadmium adsorption isotherms conformed to the Langmuir adsorption model, with adsorptive capacities of the different samples dependent on their characteristics. Equilibrium geochemical modeling (MINTEQA2) was used to predict the speciation of Cd in the soil suspensions using Langmuir and Triple Layer surface complexation models. The influence of adsorption and surface complexation on cadmium toxicity to soil microorganisms was assessed indirectly through the relative change in microbial hydrolysis of fluorescein diacetate (FDA) as a function of total Cd concentration and sorbent characteristics. Adsorption decreased the toxicity of Cd to soil microorganisms. Inner-sphere complexation is more effective than outer-sphere complexation in reducing the bioavailability and toxicity of heavy metals in soils and sediments.

• 한국환경보건학회지
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• 제45권2호
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• pp.192-202
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• 2019

Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.

• 동의생리병리학회지
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• 제18권4호
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• pp.957-964
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• 2004

Herbal medicines are increasingly used to treat various diseases and lots of studies have been reported that they had benefits in treating and preventing of diseases. But organic toxicity is increasingly recognized as herbal medicines become more popular in industrialized countries. Some herbal products potentially benefit people with lots of diseases, however these benefits remain generally unproved in humans, and a greater awareness for potential adverse effects is required. A herb containing a wide variety of, mostly unknown, substances may well include some with unwanted effects. This review focuses on emerging organic toxicities that have been observed associated with various herbal preparations involving the liver, kidney, and heart, and patterns of organ injury, potential risk factors for organic toxicities. In addition to the potential for organic toxicities, drug drug interactions between herbal medicines and conventional agents may affect the efficacy and safety of concurrent medical therapy. Appropriate reporting and regulatory system to monitor herbal toxicity are required, in conjunction with ongoing scientific evaluation of the potential benefits of phytotherapy.

• Membrane and Water Treatment
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• 제14권3호
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• pp.141-146
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• 2023

Algal organic matters (AOMs) are challenging to remove using traditional water treatment methods. Additionally, they are recognized as disinfection by product (DBP) precursors during the chlorination process. These compounds have the potential to seriously harm aquatic creatures. Despite the fact that AOMs and DBPs formed from algae can harm aquatic species by impairing their cognitive function and causing behavioral problems, only a few studies on the effects of AOMs and associated DBPs have been conducted. To assess the impact of extracellular organic materials (EOMs) produced by three different hazardous algal species and the chlorinated EOMs on zebrafish, this study used fish acute embryo toxicity (FET) and cognitive function tests. With rising EOM concentrations, the embryo's survival rate and mental capacity both declined. Of the three algal species, the embryo exposed to Microcystis aeruginosa EOM exhibited the lowest survival rate. On the other hand, the embryo exposed to EOMs following chlorination demonstrated a drop in CT values in both the survival rate and cognitive ability. These findings imply that EOMs and EOMs treated with chlorine may have detrimental effects on aquatic life. Therefore, an effective EOM management is needed in aquatic environment.

• Environmental Analysis Health and Toxicology
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• 제22권3호
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• pp.271-277
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• 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.

• 농약과학회지
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• 제16권4호
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• pp.369-375
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• 2012

황토유황합제는 우리나라에서 농작물 생산에 살균살충작용을 가지는 것으로 알려져 친환경유기농자재로 널리 사용되고 있으나, 알칼리성이 강하여 작물에 약해를 보일 뿐 아니라 농업자의 피부 및 안점막에 자극성이 있는 것으로 보고되고 있어 제품으로서의 안전성에 대한 우려가 높다. 본 연구에서는 작물의 약해를 저감하기 위해 pH를 조정하여 제조한 황토유황합제 3종(pH 9, pH 10, pH 11)의 인축 급성독성시험을 시행하여 인체 안전성을 확인함으로써 친환경유기농자재 개발시 최적의 제품 선정에 기초자료로 활용하고자 하였다. 랫드를 이용한 급성경구독성시험 결과 황토유황합제는 $LD_{50}$이 2,000 mg/kg b.w. 이상이었으며, 급성경피독성시험 결과 또한 모두 4,000 mg/kg b.w. 이상인 저자극성으로 분류되었다. 피부 및 안점막자극성 시험 결과에서도 모두 저자극성으로 구분되었으며 pH 9~11 범위에서 제품간 독성분류의 차이는 나타나지 않았다.