• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.73-77
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• 2003

• Environmental Engineering Research
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• v.21 no.4
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• pp.373-383
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• 2016

Cheonsu Bay, one of the most important in Korea as a coastal fishery is a semi-enclosed bay that is surrounded by large farmlands and industrial areas. This coastal environment has been affected by anthropogenic pollutants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The objectives of this study were to investigate the distribution of PCBs and OCPs in sediment, Manila clams, and mussels from Cheonsu Bay; the accumulation pattern of these chemicals in these bivalves in relation to seasonal changes; and the ecological risk from sediments and the risk to the Korean population from the consumption of these bivalves. The levels of ${\Sigma}PCBs$, ${\Sigma}DDT$, and ${\Sigma}HCHs$ were 69.3-109, 40.3-49.3 and 6.25-17.8 ng/g lipid in Manila clams, and 70.6-159, 38.6-102 and 9.00-13.5 ng/g lipid in Mussels. Significant seasonal variations in PCBs and OCPs concentrations were observed in the two bivalves, suggesting that the accumulation of PCBs and OCPs in these species is related to their spawning times. The dietary intake of these two bivalves and the resulting lifetime cancer risk (LCR) and non-cancer risk were calculated for the human population. The consumption of these bivalves seemed to be safe in relation to human health with negligible LCR and non-cancer risk.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.274-278
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• 2021

Road structures play an important role in collisions involving vehicles and wildlife. Our study aimed to determine the effect of various types of road structures on the risk associated with roadkill. We surveyed 50 previously identified roadkill hotspots, ranked from one to five according to roadkill density. We collected nine types of road structure data on each hotspot road section. Structures with similar characteristics were grouped together, resulting in five categories, namely, median barrier, high edge barrier, low edge barrier, speed, and visibility. We examined the existence of each road structure category at each hotspot rank. The cumulative link model showed that the absence of bottom blocked median barrier increased the roadkill hotspot rank. Our study concluded that a visual obstacle in the middle of roads by the median barrier decreases wildlife road crossing attempts and roadkill risk. We suggest that future roadkill mitigation plans should be established considering these characteristics.

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.360-365
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• 2009

Over the last five years, we have conducted research on risk assessment of domestically developed genetically modified (GM) crops and found a number of factors which could delay risk assessment process. In this review, we described such cases and discussed the problem of transgene cassette integration, the lack of information on vectors, the poor quality control in seed production and absence of bioinformatic analysis on amino acid sequence homology before GM crop development. To solve these problems, we have suggested the introduction of the screening system of elite event before risk assessment process and quality control strategies for GM seed production. In addition, we suggested that the developers of GM crops should understand the importance of risk assessment and management for the commercialization of those crops and consider the biological and ecological characteristics of host plants. Consistent communications may need to be established between GM crop developers, risk assessors and risk managers at the initial stages of GM crop development to reduce trial-and-errors.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.128-135
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• 2012

The individual toxicity of lead (Pb) and zinc (Zn) has been investigated by using the sea urchin (Hemicentrotus pulcherrimus) germ cell and pluteus-larvae. The gametotoxic and embryotoxic effects of Pb and Zn on H. pulcherrimus were each investigated at 31, 63, 125, 250, 500 ppb and 16, 31, 63, 125, 250 ppb, respectively. Spawning was induced by 0.5 M KCl solution and the fertilization and normal embryogenesis rates test were performed for 10 min and 64 h after fertilization, respectively. In exposure to Pb, the fertilization rate was not significantly changed compared with control but normal embryogenesis rate was significantly decreased with concentration dependent manner. Fertilization and normal embryogenesis rates showed a significant decreased with concentration dependent manner in exposed to Zn. The normal embryogenesis rates were significantly inhibited in exposed to Pb ($EC_{50}$=45.13 ppb, 95% Cl=40.12~50.05 ppb) and Zn ($EC_{50}$=19.82 ppb, 95% Cl=18.26~21.31 ppb). In exposure to Pb and Zn, the NOEC of normal embryogenesis rate was <31.25 and <15.63 ppb, respectively. The LOEC showed each 31.25 and 15.63 ppb in exposed to Pb and Zn. These results suggest that the early embryo development of H. pulcherrimus is highly sensitive to heavy metals such as Pb and Zn, H. pulcherrimus can be used as a test organism for risk assessment in marine ecosystems.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.14-26
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• 2023

Background: An important consideration for the risk assessment of transgenic plants is their overwintering potential in a natural ecosystem, which allows the survival of the seed bank and may lead to seed reproduction. Here, we investigated the overwintering of sunflower (Helianthus annuus L.) seeds in the laboratory (temperatures: -5, -1, 5, and 10℃) and in the field (burial depth: 0, 5, 15, and 30 cm) as a case study to examine the invasiveness of transgenic crops. Results: Sunflower seeds germinated when incubated at 5℃ and 10℃ for 2, 4, 6, and 12 weeks but not when incubated at -5℃ or -1℃. However, the seeds incubated at -5℃ or -1℃ germinated when they were transferred to the optimal germination temperature (25℃). Up to 16.5% and 15.0% of seeds were dormant when cultured at sub-zero temperatures in a Petri dish containing filter paper and soil, respectively. In the field trial, soil temperature, moisture, and microbial communities differed significantly between soil depths. Germination-related microorganisms were more distributed on the soil surface. Seeds buried on the surface decayed rapidly from 4 weeks after burial, whereas those buried at depths of 15 cm and 30 cm germinated even 16 weeks after burial. No dormancy was detected for seeds buried at any depth. Conclusions: Although sunflower seeds did not overwinter in situ in this study, we cannot exclude the possibility that these seeds lie dormant at sub-zero temperatures and then germinate at optimal temperatures in nature.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.316-322
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• 2011

BACKGROUND: Pesticides concentration was monitored in 50 agricultural lakes, and ecological risk for aquatic organism was assessed using risk quotient (RQ) and probabilistic methods. METHODS AND RESULTS: Pesticides concentrations detected in 50 agricultural lakes during peak season (June and September) were in the range of $0.17{\sim}0.99{\mu}g/L$. The RQ for algae and the other species was estimated to be 0.25 and below 0.01, indicating medium risk and no risk. Oxadiazon predominantly contributed to RQ value of 99% for algae, fishes, and amphibians. In terms of hazardous concentration at 5% of species ($HC_5$), ecological risk quotients (ERQ) for oxadiazon ranged from 0.18~0.33, showing a medium risk level. Overall, the concentrations of pesticides were much lower than $HC_5$), value. Probability of combined ecological risk for pesticides ranged from 1.82% to 2.41%. CONCLUSION(s): Combined ecological risk probability did not exceed the acceptable level of 5%, indicating no ecological risk for selected aquatic species. This study suggests that regular ecological risk assessment (ERA) will be required to protect and manage an agricultural lake. Not only ERA at screening level by comparing exposure with toxic effects for aquatic species also advanced ERA technique considering species in indigenous to Korea, chronic toxicity, pulse dose, fate, and environmental factors should be required.

• Journal of Environmental Health Sciences
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• v.44 no.6
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• pp.548-555
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• 2018

Objectives: We conducted ecological risk assessment for cadmium, a heavy metal and carcinogen, to identify safety standards by environmental media and to determine its impact on ecosystems by estimating and evaluating exposure levels. Methods: Species sensitivity distributions (SSDs) were generated using ECOTOX DB. A hazardous concentration of 5% (HC5) protective of most species (95%) in the environment was estimated. Using this estimate, predicted no effect concentrations (PNECs) were calculated for aquatic organisms. Based on the calculated PNECs for aquatic organisms, PNEC values for soil and sediment were calculated using the partition coefficient. Predicted exposure concentrations (PECs) were also calculated from environmental monitoring data with hazard quotients (HQs) calculated using PNECs for environmental media. Results: Chronic toxicity data were categorized into four groups and 11 species. In species sensitivity distribution (SSD) analysis, HC5 was $0.340{\mu}g/L$. Based on this value, the PNEC value for aquatic organisms was calculated as $0.113{\mu}g/L$. PNEC values for soil and sediments using a partition coefficient were calculated as 15.02 mg/kg and 90.61 mg/kg, respectively. In an analysis of environmental monitoring data, PEC values were calculated as $0.017{\mu}g/L$ for water, 1.01 mg/kg for soil, and 0.521 mg/kg for sediment. Conclusions: HQs were 0.150, 0.067 and 0.006 for water, soil and sediment, respectively. HQs of secondary toxicity were 0.365 for birds and 0.024 for mammals. In principle, it is judged that an HQ above 1 indicates a high level of risk concern while an HQ less than 1 indicates an extremely low level of risk concern. Therefore, with HQs of cadmium in the environment being <1, its risk levels can be considered low for each media.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.390-398
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• 2021

In this study, the toxicity of chlorothalonil was investigated using survival rate and population growth rate of a marine rotifer, Brachionus plicatilis, typically used in live food in marine aquaculture systems. The survival rate of B. plicatilis was determined after 24 h of exposure to chlorothalonil (0.010-0.156 mg L^-1). Population growth rate of B. plicatilis was calculated after 72 h of exposure to chlorothalonil (0.078-1.250 mg L^-1). The survival rate and population growth rate of B. plicatilis exposed to chlorothalonil in single-dose toxicity assessment showed concentration-dependent reductions. Survival rates of B. plicatilis exposed to chlorothalonil had the following values: NOEC, 0.020mg L^-1; LOEC, 0.039 mg L^-1; and EC₅₀, 0.057 mg L^-1. Population growth rate of B. plicatilis exposed to chlorothalonil had the following values: NOEC, 0.156 mg L^-1; LOEC, 0.313 mg L^-1; and EC₅₀, 0.506 mg L^-1. When the residual concentration of chlorothalonil in the marine coastal area was more than 0.039 mg L^-1, it had a toxic effect on B. plicatilis, a zooplankton. This paper provides toxicity values that can be used as baseline data for organizing environmental standards of chlorothalonil. It also provides insight into toxic effects of chlorothalonil on other non-target organisms.

• Asian Journal of Atmospheric Environment
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• v.5 no.4
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• pp.205-215
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• 2011

Ozone ($O_3$) is a main component of photochemical oxidants and a phytotoxic air pollutant. Although the current levels of tropospheric $O_3$ in East Asia could adversely affect productivity of forest tree species, risk assessments of $O_3$ impact were limited. In this paper, we summarize the methodology of risk assessment of $O_3$ on forest tree species based on our two previous studies, risk assessments of $O_3$ impact on the growth of Fagus crenata by Watanabe et al. (2012) and on the annual carbon absorption of three representative conifers, Cryptomeria japonica, Pinus densiflora and Larix kaempferi by Watanabe et al. (2010). $O_3$ sensitivity of each tree species obtained from an experimental study, $O_3$ exposure and atmospheric N deposition based on field monitoring and vegetation survey were integrated by geographic information system method. Based on the results, we conclude that the area with high risk of $O_3$ impact does not necessarily correspond to the area with high $O_3$ exposure. The varieties of tree habitat, tree sensitivity to $O_3$ and annual carbon absorption among the tree species, and N deposition-induced change in the $O_3$ sensitivity of F. crenata are raised as the factors of discordance between areas with high risk and those with high $O_3$ exposure. In the last part of this paper, we discuss the present uncertainty and perspectives of risk assessment for the future studies on the impact of $O_3$ on forest tree species in East Asia.